Dr. Liu is as an Associate Professor of Otolaryngology, and by courtesy, of Plastic and Reconstructive Surgery at Stanford University School of Medicine. He is director of the Stanford Sleep Surgery Fellowship, and preceptor to the Stanford Oculoplastic Surgery Fellowship. He is a Stanford Biodesign Faculty Fellow Alumnus.

After graduating from Stanford University with a degree in Biology, Dr. Liu received medical and dental degrees from the University of California-San Francisco (UCSF). He was a former Howard Hughes Medical Institute (HHMI) Research Scholar and spent a year at the NIH. After oral and maxillofacial surgery residency at UCSF, he completed the Stanford sleep surgery fellowship in 2014 with the Department of Otolaryngology and sleep surgery pioneer Dr. Robert Riley.

Dr. Liu practices the full scope of sleep apnea surgery including nasal, palate, tongue base, hypoglossal nerve stimulation, genioglossus advancement, and maxillomandibular advancement (MMA). He introduced adult maxillary expansion (DOME) for OSA with Professor Christian Guilleminault in 2015, and has continued to update the comprehensive sleep surgery protocol at Stanford.

He is also routinely referred patients who need complex facial trauma reconstruction and orthognathic surgery.

Dr. Liu's active areas of research include clinical phenotyping to optimize sleep surgery outcome, virtual surgical planning for facial skeletal surgery, and neuromodulation of the upper airway. He has given keynote talks nationally and internationally at preeminent conferences across specialties. He has published over 90 scientific articles and medical texts, with original scientific work on sleep surgery.

Academic Appointments

Administrative Appointments

  • Member, Stanford Hospital Interventional Platform Medical Committee (former Operating Room Committee) (2020 - Present)
  • Director, Stanford Sleep Surgery Fellowship (2019 - Present)
  • Co-Director, Stanford Sleep Surgery Fellowship (2015 - 2019)
  • Preceptor, Oculoplastic Surgery Fellowship (2016 - Present)

Honors & Awards

  • Scholar, Howard Hughes Medical Institute (2005-06)

Boards, Advisory Committees, Professional Organizations

  • Consultant, Sleep Disorders Committee, American Academy of Otolaryngology-Head and Neck Surgery (2018 - Present)
  • Member, Sleep Disorders Committee, American Academy of Otolaryngology-Head and Neck Surgery (2016 - 2018)

Professional Education

  • Fellowship, Stanford University, Otolaryngology - Sleep Surgery (2014)
  • Residency, University of California - San Francisco (UCSF), Oral and Maxillofacial Surgery (2013)
  • MD, University of California - San Francisco (UCSF), Medicine (2011)
  • DDS, University of California - San Francisco (UCSF), Dentistry (2007)
  • BS, Stanford University, Biology (2000)

Clinical Trials

  • SPG Neurostimulation in Cluster Patients Not Recruiting

    We hypothesized that LF stimulation of the SPG would increase parasympathetic outflow, activate sensory afferents and provoke a cluster-like attack.

    Stanford is currently not accepting patients for this trial. For more information, please contact Spectrum Child Health, 650-724-1175.

    View full details


  • Applying 3D Upper Airway Ultrasound Imaging to Clinical Diagnosis of Obstructive Sleep Apnea, Stanford University

    To “see” the airway: how it collapses during snoring for our patients with obstructive sleep apnea remains a challenge. At Stanford, we started a study using ultrasound imaging to “see” your airway in a non-invasive manner without radiation.

    An FDA-approved ultrasound device build on artificial intelligence capability (AmCAD UO) is used to see your airway. It is then compared to traditional nasopharyngoscopy (i.e., a flexible tube is inserted into the nose to see the airway). Part of your routine clinic examination.

    We hope that in the future, ultrasound visualization may become a better and easier way for you and your physician to see the airway affected by snoring and obstructive sleep apnea.


    430 Broadway Street, Redwood City, CA


2023-24 Courses

All Publications

  • Association of Backscattered Ultrasonographic Imaging of the Tongue With Severity of Obstructive Sleep Apnea in Adults. JAMA otolaryngology-- head & neck surgery Liu, S. Y., Bosschieter, P. F., Abdelwahab, M., Chao, P., Chen, A., Kushida, C. 2023


    Importance: Determining interventions to manage obstructive sleep apnea (OSA) depends on clinical examination, polysomnography (PSG) results, and imaging analysis. There remains the need of a noninvasive and cost-effective way to correlate relevant upper airway anatomy with severity of OSA to direct treatment and optimize outcome.Objective: To determine whether backscattered ultrasonographic imaging (BUI) analysis of the tongue is associated with severity of OSA in adults.Design, Setting, and Participants: In this prospective, single-center, diagnostic study of a consecutive series of patients (aged ≥18 years) at a sleep surgery clinic, the 89 included patients had a PSG within 3 years at the time of ultrasonography and BUI analysis between July 2020 and March 2022. Patients were excluded if body mass index had changed more than 10% since time of PSG. A standardized submental ultrasonographic scan with laser alignment was used with B-mode and BUI analysis applied to the tongue. The B-mode and BUI intensity were associated with the apnea-hypopnea index (AHI), a measure of severity of apnea from normal (no OSA) to severe OSA.Exposures: Ultrasonography and PSG.Main Outcomes and Measures: The main outcomes were BUI parameters and their association with AHI value.Results: Eighty-nine patients were included between July 2020 and March 2022. A total of 70 (78.7%) male patients were included; and distribution by race and ethnicity was 46 (52%) White participants, 22 (25%) Asian participants, and 2 (2%) African American participants, and 19 (21%) others. Median (IQR) age was 37.0 (29.0-48.3) years; median (IQR) BMI was 25.3 (23.2-29.8); and median (IQR) AHI was 11.1 (5.6-23.1) events per hour. At the middle to posterior tongue region, the 4 OSA severity levels explained a significant portion of the BUI variance (eta2=0.153-0.236), and a significant difference in BUI values was found between the subgroups with AHI values of less than 15 (no OSA and mild OSA) and greater than or equal to 15 (moderate OSA and severe OSA) events per hour. The echo intensity showed no significant differences. The BUI values showed a positive association with AHI, with a Spearman correlation coefficient of up to 0.43. Higher BUI values remained associated with higher AHI after correction for the covariates of BMI and age.Conclusions and Relevance: In this prospective diagnostic study, standardized BUI analysis of the tongue was associated with OSA severity. With the practicality of ultrasonography, this analysis is pivotal in connecting anatomy with physiology in treatment planning for patients with OSA.

    View details for DOI 10.1001/jamaoto.2023.0589

    View details for PubMedID 37166815

  • Comparative Efficacy of Obstructive Sleep Apnea Patients Undergoing Multilevel Surgery Followed by Upper Airway Stimulation Versus Isolated Upper Airway Stimulation. Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons Chang, C. P., Poomkonsarn, S., Giannakopoulos, H., Ma, Y., Riley, R., Liu, S. Y. 2022


    Upper Airway Stimulation (UAS) of the hypoglossal nerve is a rapidly growing management option for patients with obstructive sleep apnea (OSA). Our study compares the treatment efficacy of UAS between those who were initially ineligible for UAS but subsequently met eligibility after multilevel surgery versus those who underwent isolated UAS for the treatment of moderate to severe OSA.The investigators implemented a retrospective single-center cohort study of patients aged 18+ years who presented for surgical evaluation of OSA from 2016-2019 and underwent UAS implantation. The predictor variable was eligibility status for UAS. Initially ineligible subjects were defined as having an apnea-hypopnea (AHI) > 65 events/hr, body mass index (BMI) > 32 kg/m2, or complete concentric collapse (CCC) on drug-induced sleep endoscopy. Eligible subjects were defined as having an AHI between 15 and 65, with no CCC on drug-induced sleep endoscopy. The primary outcome was change in AHI which was measured preoperatively and 6 months post UAS implantation. Secondary outcomes were change in Epworth sleepiness scale and Fatigue severity scale. Covariates were age, sex, and BMI. Data analysis involved descriptive statistics and multivariable statistical models; P < .05 was considered significant.Thirty six patients underwent UAS implantation from 2016-2019. Eighteen patients who were initially ineligible for UAS underwent multilevel surgery, including uvulopalatopharyngoplasty, distraction osteogenesis maxillary expansion, or maxillomandibular advancement. Mean age was 62.4 ± 9 years and BMI of 29.1 ± 4 kg/m2 with 5 female patients. The cohort of 17 patients who met criteria for UAS from the start had a mean age of 62.9 ± 14 years and mean BMI of 26.7 ± 4 kg/m2 with 2 female patients. Mean AHI reduction for the multilevel group was 37.6 ± 21.2 events per hour (P < .001). Mean AHI reduction for the UAS-only group was 31.5 ± 13 events per hour (P < .001). When adjusted for age, BMI, and sex, the multilevel group had a more significant reduction (18 AHI events) compared to the isolated group (P < .001).For patients who are ineligible for UAS due to severity of OSA or CCC of the velum, multilevel surgery including maxillomandibular advancement followed by UAS confers effective post-treatment results, which was superior to the UAS-only group.

    View details for DOI 10.1016/j.joms.2022.11.015

    View details for PubMedID 36539190

  • A Minimally Invasive Nasal Endoscopic Approach to Distraction Osteogenesis Maxillary Expansion to Restore Nasal Breathing for Adults with Narrow Maxilla. Facial plastic surgery & aesthetic medicine Liu, S. Y., Ibrahim, B., Abdelwahab, M., Chou, C., Capasso, R., Yoon, A. 2022


    Background: Patients with narrow high-arch palate present with limited response to standard septal, turbinate, and valve procedures for nasal obstruction. Objective: To measure the effectiveness of minimally invasive nasal endoscopic (MINE) Lefort I osteotomy among subjects with narrow high-arched palate in managing nasal obstruction. Methods: Prospective cohort study was performed where subjects with narrow high-arched palate underwent MINE distraction osteogenesis maxillary expansion (DOME) from August 2019 to January 2021. Nasal obstruction symptom evaluation (NOSE) score, mean time to opioid cessation, and mean duration of cranial nerve V2 hypoesthesia were evaluated. Results: Among 12 subjects, the. mean NOSE score decreased from 58.89 to 15.83 (p=0.004). There were no complaints of lip mobility or deformity. Conclusion: MINI-DOME can reduce nasal obstruction in a certain phenotype of patients and further improve patient-centric outcomes by limiting the approach to the Lefort I osteotomy to an endoscopic nasal approach.

    View details for DOI 10.1089/fpsam.2021.0154

    View details for PubMedID 35179990

  • A Comprehensive Strategy for Improving Nasal Outcomes after Large Maxillomandibular Advancement for Obstructive Sleep Apnea. Facial plastic surgery & aesthetic medicine Abdelwahab, M., Poomkonsarn, S., Ren, X., Awad, M., Capasso, R., Riley, R., Most, S., Liu, S. Y. 2021


    Background: Rate of corrective nasal surgery after maxillomandibular advancement (MMA) for obstructive sleep apnea (OSA) has been reported to be 18.7% for functional and aesthetic indications. Objective: Describe a comprehensive strategy to optimize nasal outcomes with MMA for OSA. Methods: A retrospective review of patients undergoing MMA for OSA in a tertiary referral center was performed, with a comprehensive perioperative intervention to optimize nasal outcomes from January 2014 to February 2018. Outcomes included the Apnea-Hypopnea Index (AHI), oxygen saturation (SpO2) nadir, corrective nasal surgery needed after MMA, and Nasal Obstruction Symptom Evaluation (NOSE) scores. Results: AHI after MMA showed significant reduction (-34.65, p<0.001), SpO2 nadir increased (+6.08, p<0.001), and NOSE scores decreased (-5.96, p<0.001). Corrective nasal surgery needed after MMA was reported in 6.5% (8 of 122) subjects at a mean of 8.5 months, ranging from 1 to 24.7 months. Six subjects underwent either septoplasty and/or valve stenosis repair, and two subjects underwent functional and aesthetic rhinoplasty. Conclusion: A perioperative strategy was applied since 2014 that showed effectiveness in reducing post-MMA corrective nasal surgery to 6.5%.

    View details for DOI 10.1089/fpsam.2020.0569

    View details for PubMedID 34287054

  • Palatopharyngoplasty Resolves Concentric Collapse in Patients Ineligible for Upper Airway Stimulation. The Laryngoscope Liu, S. Y., Hutz, M. J., Poomkonsarn, S., Chang, C. P., Awad, M., Capasso, R. 2020


    OBJECTIVE: To determine if a modified tissue-preserving palatopharyngoplasty could convert retropalatal concentric collapse to anteroposterior or lateral patterns of collapse on drug-induced sleep endoscopy (DISE) in patients who are not candidates for upper airway stimulation due to complete circumferential collapse at the velum.METHODS: A prospective, nonconsecutive, single-blinded cohort study was performed by two sleep surgeons at a tertiary care center from 2015 to 2018. Inclusion criteria included adults >18years of age with a diagnosis of obstructive sleep apnea with an Apnea-Hypopnea Index (AHI) >15, a body mass index (BMI) <32, and <25% central apneas on polysomnography. Twelve patients with complete circumferential collapse underwent a modified palatopharyngoplasty. Postoperatively, a repeat sleep study was performed. A repeat DISE was recommended for those with incomplete surgical response (clinically and/or AHI).RESULTS: Twelve patients with complete circumferential collapse were eligible for the study. Mean BMI was 30.5. Mean preoperative AHI was 54.0 events per hour. Following a modified palatopharyngoplasty, the mean AHI was reduced to 33.1 events per hour, and 100% (12 of 12) of the patients converted from a pattern of complete circumferential collapse to either no collapse at the level of the velum (3) or an anteroposterior pattern of collapse (9).CONCLUSION: We demonstrate that a modified palatopharyngoplasty can successfully convert collapse patterns in patients with complete circumferential collapse. Further studies are required to determine the outcome of these patients following upper airway stimulation implantation.LEVEL OF EVIDENCE: 1B Laryngoscope, 2020.

    View details for DOI 10.1002/lary.28595

    View details for PubMedID 32109324

  • Does the Lack of Gender-Specific Apnea-Hypopnea Index Cutoff for Obstructive Sleep Apnea Impact Surgical Selection? Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons Chang, C. P., Dierks, E. n., Cheng, A. n., Ma, Y. n., Liu, S. Y. 2020


    The apnea-hypopnea index (AHI) is the parameter on which the severity of obstructive sleep apnea (OSA) is based and is also the determinant for both clinicians and third-party payers for surgical procedures. The purpose of this retrospective cross-sectional chart review is to examine differences in symptoms and AHI between men and women with OSA and whether this may impact timing and selection of surgical care.Retrospective cross-sectional study of patients aged 18 years and older who presented at a single center for surgical evaluation of OSA from January 2017 to 2020. AHI, oxygen desaturation index, respiratory disturbance index, and lowest oxygen saturation were obtained from polysomnography. The predictor variable was gender, and the outcome variable was AHI. Unadjusted and multivariate adjusted linear regression models were used to compare differences in AHI between gender, controlling for age, body mass index (BMI), Epworth sleepiness scale, and fatigue severity scale. Poisson regression analysis with robust error was used to assess the relative risks of antidepressant and anxiolytic medication use between genders.A total of 408 consecutive new patients seen for surgical evaluation to treat OSA (248 men and 160 women) were included. Median patient age was 40 years for men and 41 years for women. Median AHI for men was 22.1 events per hour and 13.7 for women (P < .001). When adjusted for age and BMI, men have 33.2% higher AHI than women, with age contributing to 2% and BMI contributing to 6% of the difference. When controlling for age, BMI, Epworth sleepiness scale, and fatigue severity scale, women have a 2.2 increased relative risk of taking anxiolytic or antidepressant medications.Women with OSA seeking surgery in a dedicated sleep practice have 33% lower AHI than men when controlling for age, BMI, and symptoms. Based on our findings, non-gender-specific AHI may handicap the surgeon from offering the full range of available procedures to women with OSA.

    View details for DOI 10.1016/j.joms.2020.11.001

    View details for PubMedID 33271184

  • Maxillomandibular Advancement: Contemporary Approach at Stanford. Atlas of the oral and maxillofacial surgery clinics of North America Liu, S. Y., Awad, M., Riley, R. W. 2019; 27 (1): 29–36


    Maxillomandibular advancement (MMA) for the treatment of obstructive sleep apnea (OSA) has remained a reliable and highly effective surgical intervention since its introduction in 1989. Modifications have been made to maximize skeletal movement and upper airway stability without compromising facial balance. Contemporary indications of recommending MMA prior to other soft tissue surgery are described. MMA poses unique challenges to surgeons. There are patient-related factors, including OSA, a chronic inflammatory condition with associated cardiovascular and metabolic comorbidity. Perioperative management is more complex than routine orthognathic patients. Key details are shared from a 3-decade experience at Stanford.

    View details for PubMedID 30717921

  • Sleep Surgery in the Era of Precision Medicine. Atlas of the oral and maxillofacial surgery clinics of North America Liu, S. Y., Wayne Riley, R., Pogrel, A., Guilleminault, C. 2019; 27 (1): 1–5

    View details for PubMedID 30717917

  • Distraction Osteogenesis Maxillary Expansion (DOME) for Adult Obstructive Sleep Apnea Patients with High Arched Palate. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery Liu, S. Y., Guilleminault, C. n., Huon, L. K., Yoon, A. n. 2017; 157 (2): 345–48


    A narrow maxilla with high arched palate characterizes a phenotype of obstructive sleep apnea (OSA) patients that is associated with increased nasal resistance and posterior tongue displacement. Current maxillary expansion techniques for adults are designed to correct dentofacial deformity. We describe distraction osteogenesis maxillary expansion (DOME) tailored to adult patients with OSA with narrow nasal floor and high arched palate without soft tissue redundancy. DOME is performed with placement of maxillary expanders secured by mini-implants along the midpalatal suture. This minimizes the maxillary osteotomies necessary to re-create sutural separation for reliable expansion at the nasal floor and palatal vault. We report the safety and efficacy profile of the first 20 patients at Stanford who underwent DOME.

    View details for PubMedID 28675100

  • Efficacy of Maxillomandibular Advancement Examined with Drug-Induced Sleep Endoscopy and Computational Fluid Dynamics Airflow Modeling. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery Liu, S. Y., Huon, L., Iwasaki, T., Yoon, A., Riley, R., Powell, N., Torre, C., Capasso, R. 2016; 154 (1): 189-195


    To use drug-induced sedation endoscopy (DISE) and computational fluid dynamics (CFD) modeling to study dynamic airway and airflow changes after maxillomandibular advancement (MMA), and how the changes correlate with surgical success based on polysomnography parameters.Retrospective cohort study.University medical center.DISE was rated with the VOTE (velum, oropharynx, tongue, epiglottis) classification, and CFD was used to model airflow velocity and negative pressure exerted on pharyngeal wall. Changes in VOTE score by site and CFD measurements were correlated with perioperative polysomnography outcomes of apnea-hypopnea index (AHI), apnea index (AI), oxygenation desaturation index (ODI), and lowest oxygen saturation.After MMA, 20 subjects (17 males, 3 females) with a mean age of 44 ± 12 years and body mass index of 27.4 ± 4.6 kg/m(2) showed mean decreases in AHI (53.6 ± 26.6 to 9.5 ± 7.4 events/h) and ODI (38.7 ± 30.3 to 8.1 ± 9.2 events/h; P < .001). Improvement in lateral pharyngeal wall collapse during DISE based on VOTE score correlated with the most decrease in AHI (60.0 ± 25.6 to 7.5 ± 3.4 events/h) and ODI (46.7 ± 29.8 to 5.3 ± 2 events/h; P = .002). CFD modeling showed significant positive Pearson correlations between reduction of retropalatal airflow velocity and AHI (r = 0.617, P = .04) and ODI (r = 0.773, P = .005).AHI and ODI improvement after MMA is best correlated with (1) decreased retropalatal airflow velocity modeled by CFD and (2) increased lateral pharyngeal wall stability based on VOTE scoring from DISE.

    View details for DOI 10.1177/0194599815611603

    View details for PubMedID 26740522

  • Maxillomandibular Advancement Efficacy in Obstructive Sleep Apnea Patients With Class 2 Versus 3 Dentofacial Deformity. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery Abdelwahab, M., Taheri, N., Eltahir, L., Erdogan, C., Lee, K., Liu, S. Y. 2023


    To compare the efficacy of maxillomandibular advancement (MMA) for patients with obstructive sleep apnea (OSA) with class 2 versus 3 dentofacial deformities (DFDs).Retrospective chart review.Tertiary sleep surgery center.Patients with OSA and DFD class 2 versus 3 undergoing MMA at Stanford Sleep Surgery between 2014 and 2021 were matched by preoperative body mass index (BMI), age, and sex. Postoperative outcome was compared with polysomnography measures and patient-reported outcome measures (PROMs).Twenty-eight matched subjects, 14 in each deformity group were identified and assessed. The mean age (standard deviation) was 34.29 (10.21) and 33.86 (10.23) for classes 2 and 3, respectively. The apnea-hypopnea index (AHI) decreased from 43.42 (28.30) to 9.6 (5.29) (p < .001) and 37.17 (35.77) to 11.81 (15.74) (p = .042) in class 2 and 3 subjects, respectively. The oxygen desaturation index (ODI) changed from 30.48 (24.02) to 6.88 (3.39) (p = .024) and 11.43 (11.40) to 5.44 (7.96) (p = .85) in class 2 and 3 subjects, respectively. The Epworth sleepiness scale changed from 8.93 (5.28) to 3.91 (2.70) (p = .018) and 10.23 (4.38) to 4.22 (3.07) (p = .006) in class 2 and 3 subjects, respectively.Among age, sex, and BMI-matched subjects, MMA is equally effective in both dentofacial class 2 and 3 groups, both objectively and subjectively. Preoperatively, dentofacial class 2 patients with OSA presented with the more severe disease with higher AHI and ODI. Dentofacial class 3 patients with OSA may require additional attention to improve nasal function outcomes.

    View details for DOI 10.1002/ohn.379

    View details for PubMedID 37449410

  • A Roadmap of Craniofacial Growth Modification for Children with Sleep Disordered Breathing: A Multidisciplinary Proposal. Sleep Yoon, A., Gozal, D., Kushida, C., Pelayo, R., Liu, S., Faldu, J., Hong, C. 2023


    Craniofacial modification by orthodontic techniques is increasingly incorporated in the multidisciplinary management of sleep disordered breathing in children and adolescents. With increasing application of orthodontics to this clinical population it is important for healthcare providers, families, and patients to understand the wide range of available treatments. Orthodontists can guide craniofacial growth depending on age; therefore, it is important to work with other providers for a team-based approach to sleep-disordered breathing. From infancy to adulthood the dentition and craniofacial complex change with growth patterns that can be intercepted and targeted at critical timepoints. This article proposes a clinical guideline for application of multi-disciplinary care with emphasis on dentofacial interventions that target variable growth patterns. We also highlight how these guidelines serve as a roadmap for the key questions that will influence future research directions. Ultimately the appropriate application of these orthodontic techniques will not only provide an important therapeutic option for children and adolescents with symptomatic sleep disordered breathing but may help also mitigate or prevent its onset.

    View details for DOI 10.1093/sleep/zsad095

    View details for PubMedID 37014012

  • What changes in maxillary morphology from distraction osteogenesis maxillary expansion (DOME) correlate with subjective and objective OSA measures? Sleep & breathing = Schlaf & Atmung Yoon, A., Kim, T. K., Abdelwahab, M., Nguyen, M., Suh, H. Y., Park, J., Oh, H., Pirelli, P., Liu, S. Y. 2023


    To correlate skeletal and airway measures on imaging with polysomnographic and self-reported measures after distraction osteogenesis maxillary expansion (DOME), in the effort to identify clinically relevant sites of expansion to guide treatment for adult patients with obstructive sleep apnea (OSA).This is a retrospective study reviewing subjects who underwent DOME and had the complete set of the following data: peri-treatment cone-beam computed tomography (CBCT) scans, polysomnography (PSG), Epworth Sleepiness Scale (ESS), and nasal obstruction symptom (NOSE) scores.Of 132 subjects who underwent DOME, 35 met inclusion criteria (71% men, mean age 27.7 ± 6.5 years, mean BMI 26.0 ± 6.4 kg/m2) and were enrolled in the study. There was a significant reduction in the NOSE score from 11.4 ± 5.5 to 3.6 ± 3.1, in the ESS score from 12.0 ± 4.6 to 7.1 ± 4.7, and in the apnea-hypopnea index (AHI) from 17.1 ± 15.8 to 7.01 ± 6.2 (p < 0.0001), after DOME. Nasal floor width at the nasopalatine canal level showed a statistically significant correlation with AHI reduction (p < .0001).DOME is significantly associated with reduction of nasal obstruction, sleepiness, and severity of OSA. The findings suggest that expansion at the anterior third of the bony nasal passage, specifically where the nasopalatine canal is located predicts its clinical efficacy. This site may be a useful target anatomically via imaging.

    View details for DOI 10.1007/s11325-022-02761-5

    View details for PubMedID 36806968

    View details for PubMedCentralID 3826282

  • Changes in tongue morphology predict responses in pharyngeal patency to selective hypoglossal nerve stimulation. Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine Fleury Curado, T., Pham, L., Otvos, T., Klopfer, T., Freire, C., Amorim, M. R., Nishimura, Y., Sennes, L. U., Psoter, K. J., Abdelwahab, M., Huang, A., Dedhia, R., Liu, S., Capasso, R., Oliven, A., Polotsky, V., Eisele, D., Schwartz, A. 2023


    STUDY OBJECTIVES: The major goal of the study was to determine whether changes in tongue morphology under selective hypoglossal nerve therapy for OSA were associated with alterations in airway patency during sleep when specific portions of the hypoglossal nerve were stimulated.METHODS: This case series was conducted at the Johns Hopkins Sleep Disorders Center at Johns Hopkins Bayview Medical Center. Twelve apneic patients implanted with a multi-channel targeted hypoglossal nerve stimulating system underwent mid-sagittal ultrasound tongue imaging during wakefulness. Changes in tongue shape were characterized by measuring its vertical height and polar dimensions between tongue surface and genioglossi origin in the mandible. Changes in patency were characterized by comparing airflow responses between stimulated and adjacent unstimulated breaths during NREM sleep.RESULTS: Two distinct morphologic responses were observed. Anterior tongue base and hyoid-bone movement (5.4(0.4) to 4.1(1.0)cm (median, IQR)) with concomitant increases in tongue height (5.0(0.9) to 5.6(0.7)cm) were associated with decreases in airflow during stimulation. In contrast, comparable anterior hyoid movement (tongue protrusion from 5.8(0.5) to 4.5(0.9)cm) without significant increases in height (5.2(1.6) to 4.6(0.8)cm) were associated with marked increases in in airflow during sleep.CONCLUSIONS: Tongue protrusion with preservation of tongue shape predicted increases in patency, whereas anterior movement with concomitant increases in height were associated with decreased pharyngeal patency. These findings suggest that pharyngeal patency can be best stabilized by stimulating lingual muscles that maintain tongue shape while protruding the tongue, thereby preventing it from prolapsing posteriorly during sleep.

    View details for DOI 10.5664/jcsm.10474

    View details for PubMedID 36727502

  • Automatic scoring of drug-induced sleep endoscopy for obstructive sleep apnea using deep learning. Sleep medicine Hanif, U., Kiaer, E. K., Capasso, R., Liu, S. Y., Mignot, E. J., Sorensen, H. B., Jennum, P. 2022; 102: 19-29


    Treatment of obstructive sleep apnea is crucial for long term health and reduced economic burden. For those considered for surgery, drug-induced sleep endoscopy (DISE) is a method to characterize location and pattern of sleep-related upper airway collapse. According to the VOTE classification system, four upper airway sites of collapse are characterized: velum (V), oropharynx (O), tongue (T), and epiglottis (E). The degree of obstruction per site is classified as 0 (no obstruction), 1 (partial obstruction), or 2 (complete obstruction). Here we propose a deep learning approach for automatic scoring of VOTE obstruction degrees from DISE videos.We included 281 DISE videos with varying durations (6 s-16 min) from two sleep clinics: Copenhagen University Hospital and Stanford University Hospital. Examinations were split into 5-s clips, each receiving annotations of 0, 1, 2, or X (site not visible) for each site (V, O, T, and E), which was used to train a deep learning model. Predicted VOTE obstruction degrees per examination was obtained by taking the highest predicted degree per site across 5-s clips, which was evaluated against VOTE degrees annotated by surgeons.Mean F1 score of 70% was obtained across all DISE examinations (V: 85%, O: 72%, T: 57%, E: 65%). For each site, sensitivity was highest for degree 2 and lowest for degree 0. No bias in performance was observed between videos from different clinicians/hospitals.This study demonstrates that automating scoring of DISE examinations show high validity and feasibility in degree of upper airway collapse.

    View details for DOI 10.1016/j.sleep.2022.12.015

    View details for PubMedID 36587544

  • Endonasal Septoplasty Using a Septal Cartilaginous Batten Graft for Managing Caudal Septal Deviation. Healthcare (Basel, Switzerland) Chi, J. C., Lee, S., Lee, C., Liu, S. Y., Ting, H., Tsai, Y. 2022; 10 (9)


    Caudal nasal septal deviation is an important condition altering nasal obstruction and cosmetic appearance and many surgical techniques have been published on how to correct caudal septal deviation, as successful management of caudal septal deviation is challenging. The goal of our study was to explore the effect of endonasal septoplasty using a septal cartilaginous batten graft for managing caudal septal deviation. We tested 26 participants with caudal septal deviation who received endonasal septoplasty using a septal cartilaginous batten graft from 1 April 2019 to 29 June 2022, and followed up for at least 6 months. Nasal Obstruction Symptom Evaluation (NOSE) Scale and visual analog scale (VAS) were recorded at baseline, 1 month, and 6 months after surgery. Valid samples were analyzed by repeated measures ANOVA and paired sample t-test. Average participant age was 36.15 ± 11.02 years old. The preoperative, 1-month postoperative, and 6-month postoperative NOSE scale decreased significantly (75.38 ± 15.62, 13.85 ± 7.79, and 14.04 ± 9.90; p < 0.001), while preoperative, 1-month postoperative, and 6-month postoperative VAS (convex/concave side) also improved (7.50 ± 0.81/3.38 ± 0.94, 2.27 ± 0.53/1.54 ± 0.58, and 2.31 ± 0.55/1.58 ± 0.58; p < 0.001). Our results showed that endonasal septoplasty using a septal cartilaginous batten graft had good surgical outcomes without an open scar or severe complications.

    View details for DOI 10.3390/healthcare10091739

    View details for PubMedID 36141351

  • International consensus statement on obstructive sleep apnea. International forum of allergy & rhinology Chang, J. L., Goldberg, A. N., Alt, J. A., Ashbrook, L., Auckley, D., Ayappa, I., Bakhtiar, H., Barrera, J. E., Bartley, B. L., Billings, M. E., Boon, M. S., Bosschieter, P., Braverman, I., Brodie, K., Cabrera-Muffly, C., Caesar, R., Cahali, M. B., Cai, Y., Cao, M., Capasso, R., Caples, S. M., Chahine, L. M., Chang, C. P., Chang, K. W., Chaudhary, N., Cheong, C. S., Chowdhuri, S., Cistulli, P. A., Claman, D., Collen, J., Coughlin, K., Creamer, J., Davis, E. M., Dupuy-McCauley, K. L., Durr, M. L., Dutt, M., Ali, M. E., Elkassabany, N. M., Epstein, L. J., Fiala, J. A., Freedman, N., Gill, K., Gillespie, M. B., Golisch, L., Gooneratne, N., Gottlieb, D. J., Green, K. K., Gulati, A., Gurubhagavatula, I., Hayward, N., Hoff, P. T., Hoffmann, O. M., Holfinger, S. J., Hsia, J., Huntley, C., Huoh, K. C., Huyett, P., Inala, S., Ishman, S., Jella, T. K., Jobanputra, A. M., Johnson, A. P., Junna, M. R., Kado, J. T., Kaffenberger, T. M., Kapur, V. K., Kezirian, E. J., Khan, M., Kirsch, D. B., Kominsky, A., Kryger, M., Krystal, A. D., Kushida, C. A., Kuzniar, T. J., Lam, D. J., Lettieri, C. J., Lim, D. C., Lin, H., Liu, S. Y., MacKay, S. G., Magalang, U. J., Malhotra, A., Maurer, J. T., May, A. M., Mitchell, R. B., Mokhlesi, B., Mullins, A. E., Nada, E. M., Naik, S., Nokes, B., Olson, M. D., Pack, A. I., Pang, E. B., Pang, K. P., Patil, S. P., de Perck, E. V., Piccirillo, J. F., Pien, G. W., Piper, A. J., Plawecki, A., Quigg, M., Ravesloot, M. J., Redline, S., Rotenberg, B. W., Ryden, A., Sarmiento, K. F., Sbeih, F., Schell, A. E., Schmickl, C. N., Schotland, H. M., Schwab, R. J., Seo, J., Shah, N., Shelgikar, A. V., Shochat, I., Soose, R. J., Steele, T. O., Stephens, E., Stepnowsky, C., Strohl, K. P., Sutherland, K., Suurna, M. V., Thaler, E., Thapa, S., Vanderveken, O. M., de Vries, N., Weaver, E. M., Weir, I. D., Wolfe, L. F., Woodson, B. T., Won, C. H., Xu, J., Yalamanchi, P., Yaremchuk, K., Yeghiazarians, Y., Yu, J. L., Zeidler, M., Rosen, I. M. 2022


    BACKGROUND: Evaluation and interpretation of the literature on obstructive sleep apnea is needed to consolidate and summarize key factors important for clinical management of the OSA adult patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).METHODS: Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.RESULTS: The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA and treatment on the multiple comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.CONCLUSION: This review of the literature in OSA consolidates the available knowledge and identifies the limitations of the current evidence. This effort aims to highlight the basis of OSA evidence-based practice and identify future research needs. Knowledge gaps and opportunities for improvement include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1002/alr.23079

    View details for PubMedID 36068685

  • Holistic care for OSA with emphasis on restoring nasal breathing: a review and perspective. Journal of the Chinese Medical Association : JCMA Tsai, M., Chen, H., Liu, S. Y., Lee, L., Lin, C., Chang, G., Tsai, Y., Lee, Y., Hsu, C., Li, H. 2022


    Obstructive sleep apnea (OSA) is characterized by partial or complete airway blockage during sleep. Nocturnal nasal obstruction usually leads to mouth breathing while sleeping, which worsens sleep apnea by aggravating tongue base and lateral pharyngeal wall collapse. The pathogenesis of OSA is multifactorial, and the precipitating factors vary significantly among individuals. Although continuous positive airway pressure (CPAP) is considered the first-line therapy for OSA, its adherence rate remains a challenge. Oral appliances are more suitable for simple snorers or patients with mild OSA. Maxillomandibular advancement (MMA) is highly effective for treating those with mandibular retrognathia and moderate-to-severe OSA. Intrapharyngeal surgeries yield favorable outcomes in patients with large tonsils and low tongue resting position (Friedman Stage I); however, their efficacy declines with time. Each therapy has its own strength and weakness; thus, the principle of multimodality treatment should be adopted. Nasal surgery plays an indispensable role in the holistic care for OSA. In addition to alleviating nasal congestion, nasal surgery significantly reduces snoring intensity and daytime sleepiness, which improves the quality of life of patients with OSA. Although it significantly reduces the respiratory disturbance index, its effect on the apnea-hypopnea index remains controversial. A combination of nasal surgery and multilevel pharyngeal surgery may result in better prognosis. Nasal surgery can significantly reduce the therapeutic pressure and improve the CPAP compliance of patients undergoing CPAP therapy. In conclusion, multimodality treatment and holistic care for OSA should involve nasal surgery for optimizing treatment outcomes.

    View details for DOI 10.1097/JCMA.0000000000000737

    View details for PubMedID 35507064

  • Impact of rapid palatal expansion on the size of adenoids and tonsils in children. Sleep medicine Yoon, A., Abdelwahab, M., Bockow, R., Vakili, A., Lovell, K., Chang, I., Ganguly, R., Liu, S. Y., Kushida, C., Hong, C. 2022; 92: 96-102


    Adenoid and tonsillar hypertrophy in children often leads to adverse respiratory symptoms and obstructive sleep apnea (OSA). Current clinical guidelines from the American Academy of Pediatrics and American Academy of Otolaryngology-Head and Neck Surgery recommend tonsillectomy as the first line of pediatric OSA treatment for children with tonsillar hypertrophy. Rapid palatal expansion (RPE) performed by orthodontists improves obstructive sleep apnea in children by reducing nasal airway resistance, increasing nasal volume, raising tongue posture, and enlarging pharyngeal airway. However, the role of RPE in alleviating adenoid and tonsillar hypertrophy remains elusive. In this study, we aim to evaluate the changes in adenoid and palatine tonsil sizes following RPE using 3D volumetric analysis of cone beam computational tomography (CBCT) imaging.In this retrospective cohort study, a total of 60 pediatric patients (mean age: 8.00, range: 5-15, 32 females and 28 males) who had tonsillar hypertrophy (size 3 and 4) were included and divided into the control group (n = 20) and expansion group (n = 40). The control group did not undergo any treatment. The expansion group underwent RPE using a conventional Hyrax expander, activated 0.25 mm per day for 4-6 weeks. Final CBCT scans (T2) were performed 13.8 ± 6.5 months after the initial scan (T1). Pediatric sleep questionnaire (PSQ) and BMI were obtained at each timepoint. Volumetric analysis of adenoid and palatine tonsils was performed using a combination of bony and soft tissue landmarks in CBCT scans through Anatomage Invivo 6 imaging software. Paired t-tests were used to evaluate the difference between the initial and final adenoid and tonsil volumes. p values less than 0.05 were considered statistically significant.Compared to the control group, the expansion group experienced a statistically significant decrease in both adenoid and tonsil volume. There was non-statistically significant increase in volume from T1 to T2 for the control group. For the expansion group, 90.0% and 97.5% of patients experienced significant reduction in adenoid and tonsil volume, respectively. The average volume decrease of adenoids was 16.8% while that of tonsils was 38.5%. The patients had up to 51.6% and 75.4% reduction in adenoid and tonsil size, respectively, following RPE orthodontic treatment. Pearson correlation ranged from 0.88 to 0.99 for each measurement, representing excellent internal consistency. There was a significant reduction in the PSQ scores from 5.81 ± 3.31 to 3.75 ± 2.38 in expansion group (p < 0.001).Our results demonstrated that RPE significantly reduced the size of both adenoid and palatine tonsils and revealed another long-term benefit of RPE treatment. To our knowledge, this is the first study to quantify the changes of adenoids and tonsils following RPE. RPE treatment can be considered as a valid and effective treatment option for pediatric OSA population with narrow high arch palate and adenotonsillar hypertrophy.

    View details for DOI 10.1016/j.sleep.2022.02.011

    View details for PubMedID 35390750

  • Feasibility of Distraction Osteogenesis Maxillary Expansion (DOME) in patients with persistent nasal obstruction after septoplasty. International forum of allergy & rhinology Liu, S. Y., Yoon, A., Abdelwahab, M., Yu, M. S. 1800


    BACKGROUND: Distraction osteogenesis maxillary expansion (DOME) is an emerging surgical concept for obstructive sleep apnea patients presenting with nasal obstruction, with a high-arched and narrow hard palate. We demonstrate the feasibility of DOME in the treatment of patients with persistent nasal obstruction after primary septoplasty.METHODS: A total of 32 consecutive patients with persistent nasal obstruction after septoplasty who underwent DOME were enrolled in this study. The efficacy of DOME in treating persistent nasal obstruction in septoplasty failure patients was evaluated by using the validated Nasal Obstruction Symptom Evaluation (NOSE) scale. Pre- and postoperative computed tomography (CT) scans were performed to measure the change of nasal floor width after surgery.RESULTS: The NOSE score significantly improved from 13.62±4.74 to 5.15±3.50 (p<0.001) after DOME. The postoperative CT scan showed a significant increase of the nasal floor width from 22.4±4.21 to 28.06±4.52 (p<0.01). No patient experienced major complications, such as wound infection, oronasal fistula, sinusitis, loss of incisor teeth, and malunion.CONCLUSIONS: This study shows that DOME appears to improve persistent nasal obstruction after septoplasty in patients with narrow and high-arched hard palate. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1002/alr.22931

    View details for PubMedID 34919340

  • Correlation between craniofacial changes and respiratory improvement after nasomaxillary skeletal expansion in pediatric obstructive sleep apnea patients. Sleep & breathing = Schlaf & Atmung Kim, J., Hwang, K., Kim, S., Liu, S. Y., Kim, S. 2021


    PURPOSE: The aim of this study was to investigate the correlation between the changes in respiratory function and dimensions of the nasomaxillary complex (NMC) and upper airway (UA) compartments after nasomaxillary skeletal expansion (NMSE) treatment for pediatric patients withobstructive sleep apnea (OSA).METHODS: Nonobese OSA patients (mean age, 13.6±2.9years; mean body mass index, 18.1±3.0kg/m2); mean apnea-hypopnea index (AHI, 7.0±5.4 events/h) presenting with transverse nasomaxillary constriction were evaluated before and after NMSE using cone-beam computed tomography (CBCT), home sleep test, and modified pediatric sleep questionnaire (m-PSQ). Paired t tests were performed to examine the treatment-related changes in all the parameters, and a multiple regression analysis adjusted for age and sagittal and vertical skeletal patterns was conducted to determine the dimensional parameters to affect the functional improvement.RESULTS: Among 26 patients,NMSE treatment significantly increased NMC dimensions at all tested levels and all UA compartments in CBCT, except glossopharyngeal airway. Concurrently, AHI, oxygen desaturation index, the lowest oxygen saturation (LSaO2), flow limitation (FL), snoring, and m-PSQ were significantly improved. AHI reduction was correlated with UA enlargement with no correlation with NMC expansion, whereas FL reduction was affected by NMC expansion. The minimal cross-sectional area was the most predictive of functional improvement, presenting correlations with AHI, LSaO2, and m-PSQ.CONCLUSION: NMSE can be a good treatment for pediatric OSA patients when applied to enhance the nasal and pharyngeal airway patencies beyond the NMC, ultimately to improve pharyngeal collapsibility as well as nasal airflow.

    View details for DOI 10.1007/s11325-021-02426-9

    View details for PubMedID 34181174

  • CPAP Treatment Improves Pure Tone Audiometry Threshold in Sensorineural Hearing Loss Patients with Sleep-Disordered Breathing. International journal of environmental research and public health Chi, J. C., Lee, S., Huang, R., Lai, C., Liu, S. Y., Tsai, Y., Fu, P., Ting, H. 2021; 18 (13)


    This article investigates the effects of continuous positive airway pressure (CPAP) on hearing impairment in sensorineural hearing loss (SNHL) patients with sleep-disordered breathing (SDB). This retrospective and observational study took place from September 2016 to February 2021, accumulating 77 subjects with SNHL and SDB (60.7 ± 11.1 years). Of which, 28 received CPAP treatment (63.0 ± 8.5 years). In our methodology, hearing thresholds at low, medium, high, and average frequencies are assessed by pure-tone audiometry at baseline (BL), three (3 m), six (6 m), and 12 (12 m) months. Our results show that the BL of at least three frequencies in all subjects is positively associated with old age, males, smoking, alcohol, coronary artery disease, hypertension, and apnea-hypopnea index [AHI] (all p < 0.05). Moreover, low, medium, and average frequencies are negatively correlated at CPAP-6 m (-5.60 ± 2.33, -5.82 ± 2.56, and -5.10 ± 2.26 dB; all p < 0.05) and CPAP-12 m (-7.97 ± 2.74, -8.15 ± 2.35, and -6.67 ± 2.37 dB; all p < 0.01) against corresponding measures of CPAP-BL. High, medium, and average frequencies positively correlated with age (p < 0.001 for high and average frequencies and <0.01 for medium frequencies). We conclude that in SNHL patients with SDB, hearing thresholds at low and medium frequencies improves under CPAP use after six months, which persists at least to the end of one year.

    View details for DOI 10.3390/ijerph18136768

    View details for PubMedID 34202447

  • Deep Neck Infection Risk in Patients with Sleep Apnea: Real-World Evidence. International journal of environmental research and public health Ding, M., Hsu, C., Liu, S. Y., Lee, Y., Yang, Y., Liu, C., Chang, G., Tsai, Y., Lee, L., Yang, P., Li, H., Tsai, M. 2021; 18 (6)


    (1) Background: Sleep apnea may be a risk factor for deep neck infection (DNI). The objective of this study was to investigate the effects of sleep apnea on DNI. (2) Methods: In this first nationwide retrospective cohort study on the sleep apnea-DNI correlation, we obtained data from the Longitudinal Health Insurance Database 2005, a subset of the Taiwan National Health Insurance Research Database. Patients who were newly diagnosed with sleep apnea between 1997 and 2012 were identified, and patients without sleep apnea were matched at a 1:4 ratio in age, sex, socioeconomic status, and urbanization level. The primary outcome of this study was DNI occurrence. The treatment modalities for sleep apnea and the comorbidities that occurred during the study period were also analyzed. (3) Results: Our sleep apnea and comparison (non-sleep apnea) cohorts comprised 6114 and 24,456 patients, respectively. We compared the cumulative incidence of DNI between these cohorts and found a greater incidence of DNI in the sleep apnea cohort (p < 0.001). A strong sleep apnea-DNI association was found following analysis via the adjusted Cox proportional-hazards model (full model hazard ratio, 1.71; 95% confidence interval, 1.28-2.28; p < 0.001). In the subgroup analysis, sleep apnea increased DNI risk in men, in those aged < 50 years, and in those without diabetes mellitus, end-stage renal disease, liver cirrhosis, autoimmune disease, obesity, tonsillectomy, or adenotonsillectomy. (4) Conclusions: Our results confirmed sleep apnea to be an independent risk factor for DNI. Physicians should be aware of the potential occurrence of DNI in patients with sleep apnea.

    View details for DOI 10.3390/ijerph18063191

    View details for PubMedID 33808734

  • Passing The Scalpel: A Student Initiative in Identifying and Addressing Unmet Needs in Dental Education. Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons Agari, K. M., Huang, A., Youn, S. Y., Ngo, K. Q., Hong, Y. J., Chang, C. P., Liu, S. Y. 2021


    PURPOSE: Becoming an oral-maxillofacial surgeon is often challenging for young trainees. The purpose of this manuscript is to explore how a student-led group, which emphasizes networking, mentorship, and academic opportunities, may impact one's journey to becoming an oral-maxillofacial surgeon.METHODS: This was a cross-sectional descriptive study where a 5-question Likert-type survey was administered to students who matriculated into residency and participated in a student-led group called Passing The Scalpel (PTS). This survey evaluated the value of PTS in providing exposure, career decision-making, networking/mentorship, and camaraderie. The results were analyzed, and statistical outcomes were evaluated.RESULTS: There was an 80.5% response rate (n=29). Question 1 regarding first exposure to oral-maxillofacial surgery had a mean score of 2.55 (standard deviation [SD]= 1.35; chi2=15.39; P<.05). Question 2 regarding choosing oral-maxillofacial surgery as a career had a mean score of 3.66 (SD= 1.11; chi2=10.84; P<.05). Question 3 regarding offering mentorship and networking had a mean score of 4.14 (SD= 0.92; chi2=27.81; P<.05). Question 4 regarding increasing applicant camaraderie had a mean score of 4.21 (SD= 0.77; chi2=36.71; P<.05). Question 5 regarding the importance of PTS within a dental curriculum had a score of 4.48 (SD= 0.68; chi2=41.89; P<.05).CONCLUSIONS: PTS is an effective student-led initiative that emphasizes early exposure, networking, and mentorship opportunities and encourages students in choosing oral-maxillofacial surgery as a specialty. PTS demonstrates that student-led initiatives can fulfill unmet needs in the dental curriculum.

    View details for DOI 10.1016/j.joms.2021.03.001

    View details for PubMedID 33798470

  • Estimation of Apnea-Hypopnea Index using Deep Learning on 3D Craniofacial Scans. IEEE journal of biomedical and health informatics Hanif, U. R., Leary, E. B., Schneider, L. D., Paulsen, R. R., Morse, A. M., Blackman, A., Schweitzer, P. K., Kushida, C. A., Liu, S. Y., Jennum, P., Sorensen, H. B., Mignot, E. 2021; PP


    Obstructive sleep apnea (OSA) is characterized by decreased breathing events that occur through the night, with severity reported as the apnea-hypopnea index (AHI), which is associated with certain craniofacial features. In this study, we used data from 1366 patients collected as part of Stanford Technology Analytics and Genomics in Sleep (STAGES) across 11 US and Canadian sleep clinics and analyzed 3D craniofacial scans with the goal of predicting AHI, as measured using gold standard nocturnal polysomnography (PSG). First, the algorithm detects pre-specified landmarks on mesh objects and aligns scans in 3D space. Subsequently, 2D images and depth maps are generated by rendering and rotating scans by 45-degree increments. Resulting images were stacked as channels and used as input to multi-view convolutional neural networks, which were trained and validated in a supervised manner to predict AHI values derived from PSGs. The proposed model achieved a mean absolute error of 11.38 events/hour, a Pearson correlation coefficient of 0.4, and accuracy for predicting OSA of 67% using 10-fold cross-validation. The model improved further by adding patient demographics and variables from questionnaires. We also show that the model performed at the level of three sleep medicine specialists, who used clinical experience to predict AHI based on 3D scan displays. Finally, we created topographic displays of the most important facial features used by the model to predict AHI, showing importance of the neck and chin area. The proposed algorithm has potential to serve as an inexpensive and efficient screening tool for individuals with suspected OSA.

    View details for DOI 10.1109/JBHI.2021.3078127

    View details for PubMedID 33961569

  • Role of drug-induced sleep endoscopy in evaluation of positional vs non-positional OSA. Journal of otolaryngology - head & neck surgery = Le Journal d'oto-rhino-laryngologie et de chirurgie cervico-faciale Lan, M., Liu, S. Y., Lan, M., Huang, Y., Huang, T., Hsu, Y. 2020; 49 (1): 83


    BACKGROUND: The study aimed to evaluate the anatomical differences between positional and non-positional OSA, and to identify the potential predictors for distinguishing between these two types of OSA.METHODS: A cross-sectional study of 230 consecutive patients with OSA undergoing DISE (Drug-induced Sleep Endoscopy) was carried out at a tertiary academic medical center. The factors correlating with positional and non-positional OSA were analyzed, including clinical characteristics, polysomnography data, and DISE findings.RESULTS: Univariate analysis revealed that non-positional dependency was correlated with a higher BMI (p<0.001), neck circumference (p<0.001), modified Mallampati score (p=0.003), AHI (p<0.001), degree of velum concentric collapse (p=0.004), degree of oropharyngeal lateral wall collapse (p<0.001), and degree of tongue base anteroposterior collapse (p=0.004). Multivariate analysis revealed that oropharyngeal lateral wall collapse (OR=1.90, p=0.027) was the only anatomical factor significantly predicted non-positional dependency in OSA patients. AHI (OR=1.04, p<0.001), although significant, made only a marginal contribution to the prediction of non-positional dependency.CONCLUSIONS: Oropharyngeal lateral wall collapse was identified as the only anatomical predictor for non-positional dependency in OSA patients. Therefore, further treatment modalities should address the distinct anatomical trait between positional and non-positional OSA.

    View details for DOI 10.1186/s40463-020-00478-7

    View details for PubMedID 33317645

  • Maxillomandibular Advancement and Upper Airway Stimulation: Extrapharyngeal Surgery for Obstructive Sleep Apnea. Clinical and experimental otorhinolaryngology Yu, M. S., Ibrahim, B., Riley, R. W., Liu, S. Y. 2020


    There are many ways to categorize surgery for obstructive sleep apnea (OSA), one of which is to distinguish between intrapharyngeal and extrapharyngeal procedures. While the general otolaryngologist treating OSA is familiar with intrapharyngeal procedures, such as uvulopalatopharyngoplasty and tongue base reduction, extrapharyngeal sleep operations such as maxillomandibular advancement (MMA) and upper airway stimulation (UAS) have evolved rapidly in the recent decade and deserve a dedicated review. MMA and UAS have both shown predictable high success rates with low morbidity. Each approach has unique strengths and limitations, and for the most complex of OSA patients, the two in combination complement each other. Extrapharyngeal airway operations are critical for achieving favorable outcomes for sleep surgeons.

    View details for DOI 10.21053/ceo.2020.00360

    View details for PubMedID 32683836

  • Impact of rapid palatal expansion on the internal nasal valve and obstructive nasal symptoms in children SLEEP AND BREATHING Yoon, A., Abdelwahab, M., Liu, S., Oh, J., Suh, H., Trieu, M., Kang, K., Silva, D. 2020


    The aim of this study is to evaluate the impact of rapid palatal expansion (RPE) on the nasal airway subjectively by utilizing patient-reported outcome measures (PROM) and objectively by evaluating validated internal nasal valve (INV) measurements obtained from cone beam computed tomography (CBCT) in pediatrics.In this retrospective cohort study, subjects who underwent RPE from March to December 2018 with cone beam CT and Nasal Obstruction Symptom Evaluation (NOSE) scores were included. Exclusion criteria included craniofacial deformity, allergies, asthma, recent nasal trauma, or surgery. INV measurements (angle and cross-sectional area), diastema, midpalatal suture opening, and NOSE scores were evaluated.Fifty-one subjects met the inclusion criteria with a mean age of 10.1 ± 2.6. Pre-expansion mean NOSE score was 32.55 (moderate) while post-expansion was 13.92 (mild). Mean NOSE score improved significantly by an average of 18.63 following post-expansion (P < 0.0001). The patients' right and left INV angles increased significantly by a mean of 2.42° and 2.65° respectively (P < 0.0001). Right and left INV cross-sectional areas increased significantly by an average of 14.35 mm2 (P < 0.0001) and 14.17 mm2 (P < 0.0001) respectively. An average expansion of the diastema and the suture was 1.60 mm and 3.05 mm respectively (P < 0.0001), with an average of 6.29 mm of expansion. We found the amount of diastema expansion to correlate with change in NOSE score (R = - 0.32, P = 0.022). Age and diastema showed a negative correlation (R = - 0.44, P = 0.0019), while INV angle and diastema showed a statistically significant positive correlation (R = 0.28, P = 0.048).RPE showed improvement in both NOSE scores and objective measures of the INV. This may show the possibility of considering RPE in managing resistant pediatric nasal airways. Future studies should include collaboration with pediatric otolaryngologists, with the inclusion of pediatric patients with persistent nasal obstruction.

    View details for DOI 10.1007/s11325-020-02140-y

    View details for Web of Science ID 000546893500002

    View details for PubMedID 32648185

  • Surgical Algorithm for Obstructive Sleep Apnea : An Update. Clinical and experimental otorhinolaryngology Liu, S. Y., Riley, R. W., Yu, M. S. 2020


    Sleep surgery is part of a continuum of care for OSA that involves medical, pharmacologic, and behavioral therapy. Upper airway surgery for OSA can significantly improve stability by way of modulating the critical negative closing pressure. This is the same mechanism of action as PAP or oral appliance therapy (OAT). The updated surgical algorithm in this review adds precision in 3 areas: 1) patient selection, 2) identification of previously unaddressed anatomic phenotypes with associated treatment modality, and 3) improved techniques of previously established procedures. While the original Riley and Powell Phase 1 and 2 approach to sleep surgery has focused on individual surgical success rate, this algorithm strives for an overall treatment success with multi-modal and patient-centric treatments.

    View details for DOI 10.21053/ceo.2020.01053

    View details for PubMedID 32631040

  • Upper airway stimulation as an alternative to maxillomandibular advancement for obstructive sleep apnoea in a patient with dentofacial deformity: case report with literature review INTERNATIONAL JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY Hong, S. O., Poomkonsarn, S., Millesi, G., Liu, S. C. 2020; 49 (7): 908-913


    Obstructive sleep apnoea (OSA) is characterized by repeated upper airway collapse leading to oxygen desaturation resulting in cardiovascular and neurocognitive sequelae. Upper airway surgeries such as palatopharyngoplasty, tongue base surgery, and maxillomandibular advancement can improve patient tolerance of continuous positive airway pressure, quality of life, and the severity of OSA. Upper airway stimulation (UAS) of the hypoglossal nerve is a contemporary US Food and Drug Administration-approved treatment modality for OSA with a fundamentally different mechanism. We report the case of a 65-year-old male with a high body mass index, hypertension, diabetes, dentofacial deformity, and severe OSA. He presented with a respiratory distress index (RDI) of 89.1 events per hour, apnoea-hypopnoea index (AHI) of 82.7 events per hour, and minimum oxygen saturation of 75%. He chose to undergo UAS. Initially, complete concentric collapse of the velum was found during drug-induced sedation endoscopy, which was converted by palatopharyngoplasty to meet inclusion criteria for UAS. The patient achieved surgical cure with postoperative RDI and AHI of 2 events per hour with minimum oxygen saturation of 83%, and resolution of daytime somnolence. UAS is an effective surgical option to broaden the surgeon's ability to treat OSA, especially if facial skeletal surgery is contraindicated or declined by the patient with dentofacial deformity.

    View details for DOI 10.1016/j.ijom.2019.08.008

    View details for Web of Science ID 000546907000011

    View details for PubMedID 31870520

  • The role of pediatric maxillary expansion on nasal breathing. A systematic review and metanalysis. International journal of pediatric otorhinolaryngology Calvo-Henriquez, C., Capasso, R., Chiesa-Estomba, C., Liu, S. Y., Martins-Neves, S., Castedo, E., O'Connor-Reina, C., Ruano-Ravina, A., Kahn, S. 2020; 135: 110139


    OBJECTIVE: A reduced transversal dimension of the maxilla leads to narrower nasal cavities, which may reduce airflow to the lungs. Maxillary expansion widens nasal floor. However, there is huge controversy regarding whether this increase does actually lead to increased airflow. In this systematic review and meta-analysis we aim to resolve this question by evaluating studies that have undertaken rhinomanometric measurements.REVIEW METHODS: Pubmed (Medline), the Cochrane Library, EMBASE and Trip Database were checked by two authors. Two authors extracted the data. Main outcome was expressed as the difference between resistance before and after treatment and the 95% confidence interval.RESULTS: 30 studies were selected for full text reading. A total of 12 studies (301 patients) met the inclusion criteria. All selected articles found reduced resistance after palatal expansion. The data pooled in the meta-analysis reveals a statistically significant difference of 0.12Pas/cm3 mean reduction after palatal expansion (CI 95% 0.06, 0.18) for nine uncontrolled studies. Regarding nasal airflow, the pooled data show a statistically significant difference of 29.9cm3/s increase after palatal expansion (CI 95% 9.17, 50.64).CONCLUSION: According to the available evidence, palatal expansion in pediatric patients decreases nasal resistance and increases nasal flow.

    View details for DOI 10.1016/j.ijporl.2020.110139

    View details for PubMedID 32502910

  • Safeness, subjective and objective changes after turbinate surgery in pediatric patients: A systematic review. International journal of pediatric otorhinolaryngology Calvo-Henriquez, C., Capasso, R., Martinez-Capoccioni, G., Rangel-Chaves, J., Liu, S. Y., O'Connor-Reina, C., Lechien, J. R., Martin-Martin, C. 2020; 135: 110128


    OBJECTIVE: Inferior turbinates are the main structure related to impaired nasal breathing. When medical treatment fails, surgery is the next step, according to clinical guidelines. However, despite the widespread acceptance of this procedure, there is some controversy about performing it in children.DATA SOURCES: Pubmed (Medline), the Cochrane Library, EMBASE, Scopus, Science direct, SciELO and Trip Database.REVIEW METHODS: We looked for articles in which the individual outcome of turbinate surgery in pediatric patients was investigated independently of whether it was the main objective of the study or not.RESULTS: 13 papers (1111 patients) met the inclusion criteria. 6 authors performed diverse objective assessment and 11 authors used subjective scales. All of them found improvement after surgery. Due to the heterogeneity of the methods used, they could not be included in a metanalysis. Eleven out of the 13 authors reported 3.12% complication rates, being minor bleeding the most common (1.30%), followed by crust (0.49%) and pain (0.47%).CONCLUSIONS: There is a lack of high quality studies in children. Turbinate surgery in children is a safe technique with low complication rates. The available evidence suggests improvement in subjective outcomes after turbinate surgery in children. We cannot make a formal recommendation of a surgical technique in children given the lack of high quality studies, and since comparison between available papers is not possible. Although the evidence at our disposal is weak, it suggests that the safest techniques are MAIT, radiofrequency, coblation and laser.

    View details for DOI 10.1016/j.ijporl.2020.110128

    View details for PubMedID 32485468

  • Role of rhinomanometry in the prediction of therapeutic positive airway pressure for obstructive sleep apnea. Respiratory research Hsu, Y., Liu, S. Y., Lan, M., Huang, Y., Tzeng, I., Lan, M. 2020; 21 (1): 115


    BACKGROUND: This study was conducted to evaluate the relationship between nasal resistance in different posture and optimal positive airway pressure (PAP) level. Other potential factors were also assessed for possible influence on PAP pressure.METHODS: Forty- three patients diagnosed with obstructive sleep apnea (OSA) were prospectively recruited in this study. Nasal resistance was assessed by active anterior rhinomanometry in a seated position and then in a supine position at pressures of 75, 150, and 300pascal. The factors correlating with PAP pressure were analyzed, including nasal resistance and patients' clinical data.RESULTS: Univariate analysis revealed that PAP pressure was correlated to nasal resistance in the supine position at 75 and 150pascal (SupineNR75 and SupineNR150) (P = 0.019 and P = 0.004 in Spearman's correlation coefficient analysis), but not correlated to nasal resistance in the seated position at different pressures or in the supine position at 300pascal. The multiple linear regression analysis revealed that both SupineNR150 and body mass index (BMI) significantly predicted PAP pressure (beta = 0.308, p = 0.044; beta = 0.727, p = 0.006). The final PAP pressure predictive model was: PAP pressure = 0.29 BMI + 2.65 SupineNR150 + 2.11.CONCLUSIONS: Nasal resistance in the supine position measured at 150pascal may provide valuable information regarding optimal PAP pressure. Rhinomanometry should be included in the treatment algorithm of OSA patients when PAP therapy is considered.

    View details for DOI 10.1186/s12931-020-01382-4

    View details for PubMedID 32404107

  • Multi-perspective clustering of obstructive sleep apnea towards precision therapeutic decision including craniofacial intervention. Sleep & breathing = Schlaf & Atmung Kim, S., Alnakhli, W. M., Alfaraj, A. S., Kim, K., Kim, S., Liu, S. Y. 2020


    PURPOSE: Previous studies focusing on phenotyping obstructive sleep apnea (OSA) have outlined its heterogeneity in clinical symptoms, comorbidities, and polysomnographic features. However, the role of anatomical or pathophysiological causality including craniofacial skeletal deformity has not been studied. We aimed to identify and characterize phenotypes of OSA based on multi-perspective clustering by incorporating craniofacial risks with obesity, apnea severity, arousability, symptom, and comorbidity.METHODS: A total of 421 Korean patients with OSA (apnea-hypopnea index, AHI ≥ 5; age ≥ 20 years old) were recruited. A K-means cluster analysis was performed following principal component analysis with sagittal and vertical skeletal variables (ANB and mandibular plane angle), AHI, body mass index, and Epworth sleepiness scale. Inter-cluster comparison was conducted using demographic, cephalometric, and polysomnographic variables in addition to presence of diabetes and hypertension. Risk factors contributing to OSA severity were evaluated in each cluster using multivariable regression analysis with adjustment for age and gender.RESULTS: Three phenotypic clusters were identified and characterized as follows: Cluster-1 (noncraniofacial phenotype, 39%), non-obese moderate-to-severe OSA with no skeletal discrepancy representing low arousal threshold (ArTh), little sleepiness, and low comorbidity; Cluster-2 (craniofacial skeletal phenotype, 33%), non-obese moderate OSA with definite skeletal discrepancy showing low ArTh, mild sleepiness, and low comorbidity; and Cluster-3 (complicated phenotype, 28%), obese severe OSA with skeletal discrepancy exhibiting high ArTh, excessive daytime sleepiness, and high incidence of hypertension.CONCLUSIONS: The three OSA phenotypes from multi-perspective clustering may provide a basis for precise therapeutic decision-making including craniofacial skeletal intervention beyond usual characterization of OSA subgroups.

    View details for DOI 10.1007/s11325-020-02062-9

    View details for PubMedID 32219710

  • How does distraction osteogenesis maxillary expansion (DOME) reduce severity of obstructive sleep apnea? Sleep & breathing = Schlaf & Atmung Iwasaki, T., Yoon, A., Guilleminault, C., Yamasaki, Y., Liu, S. Y. 2019


    OBJECTIVE: Distraction osteogenesis maxillary expansion (DOME) is a reliable method to expand the nasal floor and hard palatal vault in adults with obstructive sleep apnea (OSA). DOME results in a reduction in the apnea-hypopnea index (AHI) and subjective report of improved nasal breathing. Using rhinomanometry augmented computational fluid dynamic (CFD) modeling, we propose a mechanism of how DOME reduces upper airway pharyngeal collapse in adults with OSA.MATERIAL AND METHOD: A retrospective cohort with 20 subjects and mean age of 29.6 ± 8 years who completed DOME at Stanford University from September 2014 to April 2016. Subjects were included if polysomnography, airway morphology, and rhinomanometry were available for use. From the CBCT data, 3D nasal and pharyngeal airway model were generated. Numeric CFD simulation of the airway models were analyzed under the following conditions: (1) the volume of air was flowing at a velocity of 300 cm3/s, (2) the wall surface was not slippery, and (3) the simulations were repeated 1000 times to calculate mean values. Statistical analyses using SPSS v24 software included paired t tests, nonparametric Wilcoxon rank test, Friedman test with Bonferroni correction, and Spearman's correlation coefficients (p < 0.05).RESULTS: Mean AHI improved from 17.8 ± 17.6 to 7.8 ± 7.1 events per hour (p < 0.001). Mean lowest oxygen saturation improved from 88.2 ± 7.2 to 90.9 ± 4.2% (p < 0.05). Mean airflow velocity within the nasal airway decreased from 15.6 ± 7.3 to 7.4 ± 2.1 m/s (p < 0.001) after DOME. Mean negative pressure of the nasal airway, retropalatal airway, oropharyngeal airway, and hypopharyngeal airway is reduced from - 158.4 ± 115.3 to - 48.6 ± 28.7 Pa, from - 174.8 ± 119.9 to - 52.5 ± 31.3 Pa, from - 177.0 ± 118.4 to - 54.9 ± 31.8 Pa and from - 177.9 ± 117.9 to - 56.9 ± 32.1 Pa (p < 0.001), respectively. AHI positively correlated with nasal flow velocity (p < 0.05) and negatively correlated with pharyngeal airway pressure (p < 0.05). ODI was positively correlated with nasal velocity (p < 0.05) and negatively correlated with nasal airway pressure (p < 0.05), retropalatal airway pressure (p < 0.001), oropharyngeal airway pressure (p < 0.001), and hypopharyngeal airway pressure (p < 0.05).CONCLUSION: Anatomic expansion of the nasal floor with widening of the hard palatal vault from DOME is associated with reduction of nasal airflow velocity and downstream reduction of negative pressure in the pharyngeal airway. This dynamic interaction correlates with a reduction in the apnea-hypopnea index (AHI) and Oxygen Desaturation Index (ODI).

    View details for DOI 10.1007/s11325-019-01948-7

    View details for PubMedID 31823220

  • Genial tubercle position and genioglossus advancement in obstructive sleep apnea (OSA) treatment: a systematic review. Maxillofacial plastic and reconstructive surgery Chang, E. T., Kwon, Y. D., Jung, J., Capasso, R., Riley, R., Liu, S. C., Camacho, M. 2019; 41 (1): 34


    To systematically review the literature for methods to localize the genial tubercle as a means for performing an advancement of the genioglossus muscle.PubMed, Google Scholar, CRISP, EMBASE, CINAHL, and Scopus were searched from inception through June 16, 2015.One hundred fifty-two articles were screened, and the full text versions of 12 articles were reviewed in their entirety and 7 publications reporting their methodology for localizing the genial tubercle. Based upon these measurements and the results published from radiographic imaging and cadaveric dissections of all the papers included in this study, we identified the genial tubercle as being positioned within the mandible at a point 10 mm from the incisor apex and 10 mm from the lower mandibular border.Based upon the results of this review, the genial tubercles were positioned within the mandible at a point 10 mm from the incisor apex and 10 mm from the lower mandible border. It may serve as an additional reference for localizing the genial tubercle and the attachment of the genioglossus muscle to the mandible, although the preoperative radiological evaluation and the palpation of the GT are recommended to accurately isolate.

    View details for DOI 10.1186/s40902-019-0217-1

    View details for PubMedID 31544097

    View details for PubMedCentralID PMC6732264

  • Lingual frenuloplasty with myofunctional therapy: Exploring safety and efficacy in 348 cases. Laryngoscope investigative otolaryngology Zaghi, S., Valcu-Pinkerton, S., Jabara, M., Norouz-Knutsen, L., Govardhan, C., Moeller, J., Sinkus, V., Thorsen, R. S., Downing, V., Camacho, M., Yoon, A., Hang, W. M., Hockel, B., Guilleminault, C., Liu, S. Y. 2019; 4 (5): 489-496


    Ankyloglossia is a condition of altered tongue mobility due to the presence of restrictive tissue between the undersurface of the tongue and the floor of mouth. Potential implications of restricted tongue mobility (such as mouth breathing, snoring, dental clenching, and myofascial tension) remain underappreciated due to limited peer-reviewed evidence. Here, we explore the safety and efficacy of lingual frenuloplasty and myofunctional therapy for the treatment of these conditions in a large and diverse cohort of patients with restricted tongue mobility.Four hundred twenty consecutive patients (ages 29 months to 79 years) treated with myofunctional therapy and lingual frenuloplasty for indications of mouth breathing, snoring, dental clenching, and/or myofascial tension were surveyed. All procedures were performed by a single surgeon using a scissors and suture technique. Safety and efficacy was assessed >2 months postoperatively by means of patient-reported outcome measures.In all, 348 surveys (83% response rate) were completed showing 91% satisfaction rate and 87% rate of improvement in quality of life through amelioration of mouth breathing (78.4%), snoring (72.9%), clenching (91.0%), and/or myofascial tension (77.5%). Minor complications occurred in <5% of cases including complaints of prolonged pain or bleeding, temporary numbness of the tongue-tip, salivary gland issues, minor wound infection or inflammation, and need for revision to excise scar tissue. There were no major complications.Lingual frenuloplasty with myofunctional therapy is safe and potentially effective for the treatment of mouth breathing, snoring, clenching, and myofascial tension in appropriately selected patient candidates. Further studies with objective measures are merited.3.

    View details for DOI 10.1002/lio2.297

    View details for PubMedID 31637291

    View details for PubMedCentralID PMC6793603

  • Augmented reality for image guidance in transoral robotic surgery. Journal of robotic surgery Chan, J. Y., Holsinger, F. C., Liu, S., Sorger, J. M., Azizian, M., Tsang, R. K. 2019


    With the advent of precision surgery, there have been attempts to integrate imaging with robotic systems to guide sound oncologic surgical resections while preserving critical structures. In the confined space of transoral robotic surgery (TORS), this offers great potential given the proximity of structures. In this cadaveric experiment, we describe the use of a 3D virtual model displayed in the surgeon's console with the surgical field in view, to facilitate image-guided surgery at the oropharynx where there is significant soft tissue deformation. We also utilized the 3D model that was registered to the maxillary dentition, allowing for real-time image overlay of the internal carotid artery system. This allowed for real-time visualization of the internal carotid artery system that was qualitatively accurate on cadaveric dissection. Overall, this shows that virtual models and image overlays can be useful in image-guided surgery while approaching different sites in head and neck surgery with TORS.

    View details for DOI 10.1007/s11701-019-01030-0

    View details for PubMedID 31555957

  • Genial tubercle position and genioglossus advancement in obstructive sleep apnea (OSA) treatment: a systematic review MAXILLOFACIAL PLASTIC AND RECONSTRUCTIVE SURGERY Chang, E. T., Kwon, Y., Jung, J., Capasso, R., Riley, R., Liu, S. C., Camacho, M. 2019; 41 (1)
  • Lingual frenuloplasty with myofunctional therapy: Exploring safety and efficacy in 348 cases LARYNGOSCOPE INVESTIGATIVE OTOLARYNGOLOGY Zaghi, S., Valcu-Pinkerton, S., Jabara, M., Norouz-Knutsen, L., Govardhan, C., Moeller, J., Sinkus, V., Thorsen, R. S., Downing, V., Camacho, M., Yoon, A., Hang, W. M., Hockel, B., Guilleminault, C., Liu, S. 2019

    View details for DOI 10.1002/lio2.297

    View details for Web of Science ID 000482692400001

  • Clinical Trials in Obstructive Sleep Apnea: Recognizing Trends and Future Opportunities Singh, S. K., Gu, D., Capasso, R., Liu, S., Gouveia, C. J. WILEY. 2019: 1940–44

    View details for DOI 10.1002/lary.27453

    View details for Web of Science ID 000481836100038

  • Impact of Distraction Osteogenesis Maxillary Expansion on the Internal Nasal Valve in Obstructive Sleep Apnea OTOLARYNGOLOGY-HEAD AND NECK SURGERY Abdelwahab, M., Yoon, A., Okland, T., Poomkonsarn, S., Gouveia, C., Liu, S. 2019; 161 (2): 362–67
  • Severe Obstructive Sleep Apnea With Imaged Carotid Plaque Is Significantly Associated With Systemic Inflammation JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY Lee, U. K., Liu, S., Zeidler, M. R., Hoang-Anh Tran, Chang, T., Friedlander, A. H. 2019; 77 (8): 1636–42
  • Optimizing mandibular sagittal split of large maxillomandibular advancements for obstructive sleep apnea: patient and surgical factors. Clinical oral investigations Chen, Y. F., Ko, E. C., Zaghi, S., Yoon, A., Williams, R., Riley, R., Liu, S. Y. 2019


    OBJECTIVES: Maxillomandibular advancement (MMA) confers consistent and high rates of surgical success for obstructive sleep apnea (OSA). In the era of value-based medicine, identifying factors that affect the stability of rigid fixation and allow rapid return to function are important targets for improvement. The aim of this study was to identify patient and surgical factors associated with mandibular sagittal split outcomes associated with optimal postoperatively skeletal stability.STUDY DESIGN: Retrospective cohort study.MATERIALS AND METHODS: Forty-six subjects (43 males and 3 females) with postoperative CT scans including three-dimensional reconstruction from which mandibular split patterns could be analyzed were enrolled. Patient factors (age and polysomnographic measures) and surgical factors (extent of osteotomy prior to controlled fracture) were assessed. Outcome measures include (1) bone thickness for rigid fixation and (2) area of passive bony overlap after advancement.RESULTS: Age and severity of disease did not contribute significantly to optimal mandibular split patterns. For optimal area for passive bony overlap and thickness of buccal and lingual plates for rigid fixation, the most important factors are related to surgical technique.CONCLUSIONS: Anterior osteotomy just to the midline of inferior border and horizontal osteotomy to the mandibular foramen are associated with split patterns that result in optimal rigid fixation and passive bony overlap for OSA patients undergoing MMA.CLINICAL RELEVANCE: Optimal surgical technique has the most significant influence in allowing rapid return to function after MMA in patients with OSA.

    View details for DOI 10.1007/s00784-019-03017-5

    View details for PubMedID 31332567

  • The Upper Airway Nasal Complex: Structural Contribution to Persistent Nasal Obstruction Williams, R., Patel, V., Chen, Y., Tangbumrungtham, N., Thamboo, A., Most, S. P., Nayak, J. V., Liu, S. C. SAGE PUBLICATIONS LTD. 2019: 171–77
  • Distraction Osteogenesis Maxillary Expansion (DOME) for adult obstructive sleep apnea patients with narrow maxilla and nasal floor. Sleep medicine Yoon, A., Guilleminault, C., Zaghi, S., Liu, S. Y. 2019


    OBJECTIVES: This study correlates objective and subjective measurements associated with obstructive sleep apnea (OSA) to define the efficacy of Distraction Osteogenesis Maxillary Expansion (DOME) to treat adult OSA patients with narrow maxilla and nasal floor.METHODS: This is a retrospective study reviewing cases from September 2014 through April 2018 with 75 eligible subjects. Inclusion criteria required OSA confirmed by attended polysomnography (PSG). Pre- and Post-operative clinical data were measured at the Stanford Sleep Medicine and Stanford Sleep Surgery Clinics. DOME is a two-step process starting with insertion of custom-fabricated maxillary expanders anchored to the hard palate by mini-implants followed by minimally invasive osteotomies. After maxillary expansion was complete, orthodontic treatment to restore normal occlusion was initiated. Perioperative Apnea-Hypopnea Index (AHI), Epworth Sleepiness Scale (ESS), Nasal Obstruction Symptom Evaluation (NOSE), and Oxygen Desaturation Index (ODI) were measured for 43, 72, 72, and 34 subjects respectively. Statistical analysis was performed using paired T-test with significance set at p-value < 0.05.RESULTS: The mean age of test subjects was 30.5±8.5 years with a gender distribution of 57 males and 18 females. There was a significant reduction in pre and post-operative NOSE score (10.94±5.51 to 3.28±2.89, p<0.0001), mean ESS score (10.48±5.4 to 6.69±4.75, p<0.0001), and AHI (17.65±19.30 to 8.17±8.47, p<0.0001) with an increased percentage of REM sleep (14.4±8.3% to 22.7±6.6%, p=0.0014). No significant adverse effects were identified.CONCLUSIONS: DOME treatment reduced the severity of OSA, refractory nasal obstruction, daytime somnolence, and increased the percentage of REM sleep in this selected cohort of adults OSA patients with narrow maxilla and nasal floor.

    View details for DOI 10.1016/j.sleep.2019.06.002

    View details for PubMedID 31606311

  • Impact of Distraction Osteogenesis Maxillary Expansion on the Internal Nasal Valve in Obstructive Sleep Apnea. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery Abdelwahab, M., Yoon, A., Okland, T., Poomkonsarn, S., Gouveia, C., Liu, S. Y. 2019: 194599819842808


    OBJECTIVE: To assess the effect of distraction osteogenesis maxillary expansion (DOME) on objective parameters of the internal nasal valve and correlate findings with subjective outcomes.STUDY DESIGN: Retrospective cohort study.SETTING: Tertiary referral center.SUBJECTS AND METHODS: After Institutional Review Board approval, included subjects were those with obstructive sleep apnea, had undergone DOME from September 2014 to April 2018, and had cone beam computed tomography scans available before and after expansion. Measurement of the internal nasal valve parameters was performed with Invivo6 Software (version 6.0.3). Interrater reliability of all pre- and postexpansion parameters was measured. Patient-reported outcome measures included the Nasal Obstruction and Septoplasty Effectiveness Scale (NOSE) and Epworth Sleepiness Scale scores, and correlation between objective and subjective outcomes were evaluated by Spearman correlation analysis.RESULTS: Thirty-two subjects met inclusion criteria. All showed significant improvement in their subjective outcomes as well as an increase in their internal valve parameters. Significant correlation was observed between increased angles and improvement in postexpansion NOSE score (right angle, P = .024; left angle, P = .029).CONCLUSION: DOME widens the internal nasal valve objectively (dimensions), which correlates significantly with subjective improvement (NOSE scores).

    View details for PubMedID 31084256

  • Effect of nasal and sinus surgery in patients with and without obstructive sleep apnea ACTA OTO-LARYNGOLOGICA Wang, M., Liu, S., Zhou, B., Li, Y., Cui, S., Huang, Q. 2019; 139 (5): 467–72
  • The Upper Airway Nasal Complex: Structural Contribution to Persistent Nasal Obstruction. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery Williams, R., Patel, V., Chen, Y., Tangbumrungtham, N., Thamboo, A., Most, S. P., Nayak, J. V., Liu, S. Y. 2019: 194599819838262


    OBJECTIVE: To determine the contribution of the nasal floor and hard palate morphology to nasal obstruction for nonresponders to prior intranasal surgery.STUDY DESIGN: Retrospective case-control study.SETTING: Tertiary academic center.METHODS: Institutional review board-approved, retrospective institutional database analysis was obtained of a cohort of 575 patients who presented with nasal obstruction over a 21-year period. Of the patients, 89 met inclusion criteria: 52 were placed into the experimental group, defined as having persistent nasal obstruction following endoscopic sinus surgery (ESS), septoplasty, nasal valve repair, and/or turbinoplasty using validated subjective questionnaires, and 37 were placed into the control group, defined as having resolution of subjective nasal obstruction. Computed tomography imaging was presented to 3 blinded experts, who measured numerous nasal airway and hard palate morphology parameters, including anterior nasal floor width, anterior maxillary angle, maxilla width, anterior nasal floor width, and palatal vault height. Standard demographic information, comorbidities, perioperative 22-item Sinonasal Outcome Test (SNOT-22), and follow-up time were also assessed. Wilcox rank sum analysis or t test was performed where appropriate.RESULTS: Follow-up ranged from 2 to 36 months following surgical intervention. Several skeletal characteristics within the upper airway were significantly associated with persistent nasal obstruction, including acute maxillary angle ( P = .035), narrow maxillary width ( P = .006), and high arched palate ( P = .004).CONCLUSION: Persistent nasal obstruction may be seen in patients with narrow, high arched hard palate despite prior nasal surgical intervention and may benefit from additional skeletal remodeling procedures such as maxillary expansion.

    View details for PubMedID 30909809

  • The Role of the Revised Stanford Protocol in Today's Precision Medicine. Sleep medicine clinics Liu, S. Y., Awad, M., Riley, R., Capasso, R. 2019; 14 (1): 99–107


    Whereas the original Stanford protocol relied on a tiered approach to care to avoid unnecessary surgery, it did not address the issue of surgical relapse, a common concern among sleep medicine specialists. With 3 decades of experience since the original 2-tiered Powell-Riley protocol was introduced and the role of evolving skeletal techniques and upper airway stimulation, we are pleased to present our current protocol. This update includes emphasis on the facial skeletal development with impact on function including nasal breathing, and the incorporation of upper airway stimulation. The increased versatility of palatopharyngoplasty as an adjunctive procedure is also discussed.

    View details for PubMedID 30709539

  • Sleep Surgery: From Reconstruction to Restoration and Re-education. Atlas of the oral and maxillofacial surgery clinics of North America Liu, S. Y. 2019; 27 (1): xi

    View details for PubMedID 30717929

  • Upper Airway (Hypoglossal Nerve) Stimulation for Treatment of Obstructive Sleep Apnea. Atlas of the oral and maxillofacial surgery clinics of North America Gupta, R. J., Kademani, D., Liu, S. Y. 2019; 27 (1): 53–58

    View details for PubMedID 30717924

  • Tonsillectomy and Pharyngoplasty: Tissue-Preserving Techniques. Atlas of the oral and maxillofacial surgery clinics of North America Awad, M., Gouveia, C., Capasso, R., Liu, S. Y. 2019; 27 (1): 17–22

    View details for PubMedID 30717919

  • The Role of the Revised Stanford Protocol in Today's Precision Medicine SLEEP MEDICINE CLINICS Liu, S., Awad, M., Riley, R., Capasso, R. 2019; 14 (1): 99-+
  • Drug-Induced Sleep Endoscopy and Surgical Outcomes: A Multicenter Cohort Study LARYNGOSCOPE Green, K. K., Kent, D. T., D'Agostino, M. A., Hoff, P. T., Lin, H., Soose, R. J., Gillespie, M., Yaremchuk, K. L., Carrasco-Llatas, M., Woodson, B., Jacobowitz, O., Thaler, E. R., Barrera, J. E., Capasso, R., Liu, S., Hsia, J., Mann, D., Meraj, T. S., Waxman, J. A., Kezirian, E. J. 2019; 129 (3): 761–70

    View details for DOI 10.1002/lary.27655

    View details for Web of Science ID 000458925600044

  • Effect of nasal and sinus surgery in patients with and without obstructive sleep apnea. Acta oto-laryngologica Wang, M., Liu, S. Y., Zhou, B., Li, Y., Cui, S., Huang, Q. 2019: 1–6


    BACKGROUND: Nasal obstruction is associated with snoring, sleep disordered breathing, and OSA. Abnormal nasal physiology is an important aspect of OSA etiology.AIMS/OBJECTIVES: To perform a systematic review and meta-analysis to determine if isolated nasal surgery in patients with and without OSA could improve sleep quality after surgery.MATERIAL AND METHODS: Computerized searches were performed in PubMed, Scopus, google scholar and the Cochrane library through June 2017. Two independent investigators performed the articles searching, screening and the data extraction.RESULTS: There were 19 studies meeting inclusion and exclusion criteria including a total of 896 patients. These studies were divided into two subgroups depending on diagnosis with and without OSA. In subgroup OSA (n=14), there was a significant improvement in the pooled results of Epworth Sleepiness Scale (ESS) with isolated nasal surgery. In subgroup without OSA (n=5), the pooled mean difference of ESS before and after surgery was similar. In each subgroup, there was no significant improvement in the Apnea Hypopnea Index.CONCLUSIONS: The pooled results showed isolated nasal and sinus surgery for patients with OSA could improve subjective sleep parameters and reduce daytime sleepiness, but had no significant improvements on objective parameters. In patients without OSA, it was ineffective to improve sleep quality.

    View details for PubMedID 30806123

  • Severe Obstructive Sleep Apnea With Imaged Carotid Plaque Is Significantly Associated With Systemic Inflammation. Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons Lee, U. K., Liu, S. Y., Zeidler, M. R., Tran, H., Chang, T. I., Friedlander, A. H. 2019


    PURPOSE: Persons with obstructive sleep apnea (OSA) are at heightened risk of myocardial infarction (MI) and stroke caused by adiposity and intermittent hypoxia, which provoke proinflammatory cytokines to induce systemic and vascular inflammation, resulting in endothelial dysfunction and development of atherosclerotic plaque. This study compared levels of systemic inflammation between groups of patients with severe OSA with and without carotid artery calcified plaque (CACP+ and CACP-, respectively) on their panoramic image (PI) as indexed by the neutrophil-to-lymphocyte ratio (NLR).MATERIALS AND METHODS: This study had a retrospective cross-sectional study design. Medical records and PIs of men with severe OSA treated by the dental service (January 1, 2017 to December 31, 2017) were reviewed. The predictor variable was the presence or absence of CACP on PIs and the outcome variable was NLR. The t test was used to analyze differences in mean NLRs between groups. Atherogenic risk factors (age, body mass index, hypertension, and diabetes) were assessed for independence by descriptive and logistic regression analyses. Significance set at .05 for all tests.RESULTS: The study group (n=39) of patients with CACP+ (mean age, 63±7.4yr) showed a mean NLR of 3.09±1.42. The control group (n=46) of patients with CACP- (mean age, 62±6.8yr) showed a mean NLR of 2.10±0.58. The difference between groups was significant (P<.001). Logistic regression for NLR and CACP failed to show meaningful correlations with covariates.CONCLUSION: Older men with severe OSA and carotid atheromas on PIs show substantially greater systemic inflammation measured by NLRs. The combination of severe OSA, atheroma formation, and markedly increased NLR suggests a higher risk of MI and stroke and greater need for cardiovascular and cerebrovascular evaluation.

    View details for PubMedID 30851255

  • Severity of Obstructive Sleep Apnea Is Positively Associated With the Presence of Carotid Artery Atheromas JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY Chang, T., Lee, U. K., Zeidler, M. R., Liu, S., Polanco, J. C., Friedlander, A. H. 2019; 77 (1): 93–99
  • Surgery in Adults CURRENT CONCEPTS OF SLEEP APNEA SURGERY Blumen, M., Sommer, U., Verse, T., Hamans, E., Liu, S., Guilleminault, C., Yoon, A., Verse, T., DeVries, N. 2019: 147–258
  • Drug-Induced Sleep Endoscopy and Surgical Outcomes: A Multicenter Cohort Study. The Laryngoscope Green, K. K., Kent, D. T., D'Agostino, M. A., Hoff, P. T., Lin, H., Soose, R. J., Boyd Gillespie, M., Yaremchuk, K. L., Carrasco-Llatas, M., Tucker Woodson, B., Jacobowitz, O., Thaler, E. R., Barrera, J. E., Capasso, R., Liu, S. Y., Hsia, J., Mann, D., Meraj, T. S., Waxman, J. A., Kezirian, E. J. 2018


    OBJECTIVE: To evaluate the association between findings of blinded reviews of preoperative drug-induced sleep endoscopy (DISE) examinations using the VOTE Classification and obstructive sleep apnea (OSA) surgical outcomes in a large multicenter, international cohort.METHODS: Retrospective, multi-center cohort study of adults without tonsillar hypertrophy who underwent pharyngeal surgery for OSA. The study included only participants without enlarged tonsils. Four independent reviewers performed blinded review of preoperative DISE videos using the VOTE Classification system and scoring of a primary structure contributing to airway obstruction. DISE findings were examined for an association with surgical outcomes with univariate analyses and multiple regression.RESULTS: Two hundred seventy-five study participants were included from 14 centers. Mean age was 51.4±11.8 years, and body mass index was 30.1±5.2kg/m2 . There was moderate interrater reliability (kappa=0.40-0.60) for DISE findings. Oropharyngeal lateral wall-related obstruction was associated with poorer surgical outcomes (adjusted odds ratio (AOR) 0.51; 95% CI 0.27, 0.93). Complete tongue-related obstruction was associated with a lower odds of surgical response in moderate to severe OSA (AOR 0.52; 95% CI 0.28, 0.98), with findings that were similar but not statistically significant in other analyses. Surgical outcomes were not clearly associated with the degree and configuration of velum-related obstruction or the degree of epiglottis-related obstruction. Surgical response was associated with tonsil size and body mass index (inversely).CONCLUSION: DISE findings concerning the oropharyngeal lateral walls and tongue may be the most important findings of this evaluation technique.LEVEL OF EVIDENCE: 2b Laryngoscope, 2018.

    View details for PubMedID 30588639

  • Changing practice: Trends in skeletal surgery for obstructive sleep apnea. Journal of cranio-maxillo-facial surgery : official publication of the European Association for Cranio-Maxillo-Facial Surgery Awad, M., Gouveia, C., Zaghi, S., Camacho, M., Liu, S. Y. 2018


    OBJECTIVES/HYPOTHESIS: The objective of this study was to systematically review the English literature for articles that have described skeletal surgeries in the treatment of obstructive sleep apnea in both adults and children. From these articles trends and patterns in the treatment of OSA with skeletal procedures are described.STUDY DESIGN: Three databases including MEDLINE, Google Scholar and the Cochrane Library were searched through May 1, 2018.METHODS: The systematic and independent literature reviews were performed and the determination of included studies was made by consensus. Relevant studies were examined based on six categories of skeletal surgery: 1) Hyoid Advancement 2) Genioplasty/Genioglossus Advancement 3) Maxillary Expansion 4) Maxillomandibular Advancement 5) Mandibular Distraction and 6) Maxillomandibular Expansion.RESULTS: 1875 studies were analyzed for inclusion of which 414 were ultimately included in our analysis. A steady increase in the publication of articles pertaining to maxillary expansion and maxillomandibular advancement was identified. Research interest in hyoid advancement and genioplasty/genioglossus advancement has declined in the past decade.CONCLUSIONS: Changing trends in skeletal surgery for OSA offer exciting and efficacious therapeutic surgical modalities. MMA is the most widely studied and efficacious multi-level surgery for OSA today. Newer modalities such as adult maxillary expansion offer encouraging early results with minimal complication rates, and further study should be directed in this area.

    View details for DOI 10.1016/j.jcms.2018.11.005

    View details for PubMedID 31182256

  • Clinical Trials in Obstructive Sleep Apnea: Recognizing Trends and Future Opportunities. The Laryngoscope Singh, S. K., Gu, D., Capasso, R., Liu, S., Gouveia, C. J. 2018


    OBJECTIVES/HYPOTHESIS: Examine US and international clinical trials in obstructive sleep apnea (OSA) to characterize researchers involved, interventions being studied, and opportunities for future investigation.STUDY DESIGN: Retrospective database review.METHODS: The information from was used to assess OSA clinical trials between 1999 and 2017. Information was gathered on principle investigator (PI) demographics, interventions studied, study funding source, and regional distribution of research institutions.RESULTS: There were 813 clinical trials studied. The majority of trials examined continuous positive airway pressure interventions (43.7%), with pharmacotherapies being the second most commonly investigated treatment (19.2%). Surgical interventions made up 10.7% (n=87) of clinical trials for OSA. Most studies were based internationally (59.9%). PIs were predominantly male (72.0%); 72.7% had an MD and 28.6% had a PhD. There were no significant differences in funding source (National Institutes of Health vs. industry, P=.14) or institutional geography (international vs. US, P=.73) between surgical and nonsurgical studies. Surgical trials were significantly more likely to have a male PI and involve pediatric patients compared to nonsurgical trials (P<.001). Otolaryngologists represented 9.2% of all PIs and had similar rates of NIH funding compared to other medical specialists (P=.22).CONCLUSIONS: This study provides a broad overview of past, current, and future treatment paradigms for OSA. Sleep surgery, specifically otolaryngology, is a small voice in the overall landscape of clinical trials for OSA. This information can help guide future research efforts and direct our specialty when setting priorities regarding research funding while encouraging a broad and interdisciplinary pursuit.LEVEL OF EVIDENCE: NA. Laryngoscope, 2018.

    View details for PubMedID 30284271

  • Publication Trends and Levels of Evidence in Obstructive Sleep Apnea Literature LARYNGOSCOPE Gouveia, C. J., Zaghi, S., Awad, M., Camacho, M., Liu, S. C., Capasso, R., Kern, R. C. 2018; 128 (9): 2193–99

    View details for DOI 10.1002/lary.27075

    View details for Web of Science ID 000446523700042

  • Severity of Obstructive Sleep Apnea Is Positively Associated With the Presence of Carotid Artery Atheromas. Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons Chang, T. I., Lee, U. K., Zeidler, M. R., Liu, S. Y., Polanco, J. C., Friedlander, A. H. 2018


    PURPOSE: Hypoxemia and hypertension caused by obstructive sleep apnea (OSA) often result in atherosclerosis of the carotid and coronary vessels and heightened risk of stroke and myocardial infarction (MI). Therefore, this study investigated whether severity of OSA, based on the apnea-hypopnea index (AHI), isassociated with the presence of calcified carotid artery (atherosclerotic) plaque (CCAP) seen on panoramic images (PIs).MATERIALS AND METHODS: Using a cross-sectional study design, the electronic medical records and PIs of all male patients referred from the sleep medicine service to the dental service from 2010 through 2016 were reviewed. The predictor variable was the patients' OSA intensity level as defined by the American Academy of Sleep Medicine based on the AHI score. The outcome variable was the presence of CCAP on the PI. Other variables of interest, that is, demographic and atherogenic risk factors (age, body mass index, diabetes, hypertension, and hyperlipidemia), were included in a multivariate analysis to assess the association of OSA with CCAP.RESULTS: The study sample consisted of 108 men (mean age, 54.7±13.5yr). Approximately one third (n=33; 30.6%) presented with CCAP and this group was significantly older with greater odds of co-diagnosis of diabetes (P<.05). Patients with more "severe" OSA showed significantly greater odds of having CCAP on their PIs compared with those with "milder" OSA (odds ratio=1.035; 95% confidence interval, 1.008-1.062; P=.010) when adjusted for confounders.CONCLUSION: There is a significant association between severity of OSA and the presence of CCAP visibleon PI. These atherosclerotic plaques are "risk factors" for stroke and "risk indicators" for future MI; therefore, clinicians providing corrective airway surgery for these patients and notingconcomitant CCAP on PI should refer these patients for a thorough cerebrovascular and cardiovascular workup.

    View details for PubMedID 30213534

  • YouTube as a source of information for obstructive sleep apnea AMERICAN JOURNAL OF OTOLARYNGOLOGY Singh, S. K., Liu, S., Capasso, R., Kern, R. C., Gouveia, C. J. 2018; 39 (4): 378–82


    Assess the quality of information on obstructive sleep apnea (OSA) presented on YouTube for patients."Obstructive sleep apnea" was entered into the YouTube search. Two independent reviewers categorized and analyzed videos utilizing a customized scoring-system along with search position, likes, and views.Forty-eight videos were analyzed. Most were educational (52.1%). Educational and news videos had significantly higher scores, but had no significant differences in search position, likes/day, or views/day. Most videos mentioned positive airway pressure (65%), and nearly half (44%) mentioned mandibular devices in the management of OSA. Few videos discussed surgery (13%) or otolaryngology (15%).YouTube is a promising source of information for OSA patients. Educational and news videos are of highest quality. General quality measures like search position, views, and likes are not correlated with formally scored value. Sleep surgery and otolaryngologists are minimally mentioned, representing an opportunity for improvement.

    View details for PubMedID 29605236

  • "Split to save": Accessing mandibular lesions using sagittal split osteotomy with virtual surgical planning ENT-EAR NOSE & THROAT JOURNAL Liu, S., Sidell, D., Huon, L., Torre, C. 2018; 97 (3): 91–96


    Large, benign intramandibular lesions are frequently removed by resection followed by extensive free tissue transfer or delayed bone grafting. We outline a protocol to remove benign mandibular lesions using sagittal split osteotomy (SSO) with virtual surgical planning (VSP) to mitigate risks involved with this effective, tissue-saving approach. Patients with benign mandibular lesions accessed by SSO with VSP during 2014 were included in this study. Computed tomographic data were imported into VSP software. Using VSP, the exact locations of mandibular lesions and the inferior alveolar nerve canal were delineated. SSO was designed virtually and provided surgeons exact measurements to gain access to lesions and to avoid vital structures intraoperatively. SSO with VSP preserved the cortical mandibular bone and the inferior alveolar neurovascular bundle in 3 patients with benign mandibular lesions. Twelve months after surgery, no patient had pathologic fracture, prolonged paresthesia (except for the patient who required inferior alveolar nerve resection), or malocclusion. No patient required bone grafting. There were no functional or aesthetic jaw deficits. SSO is an effective approach to access intramandibular lesions. The technique does not result in loss of mandibular bone, and patients return to full masticatory function compared with those who require resection and reconstruction. VSP may mitigate technical challenges associated with SSO.

    View details for PubMedID 29554403

  • Publication trends and levels of evidence in obstructive sleep apnea literature. The Laryngoscope Gouveia, C. J., Zaghi, S. n., Awad, M. n., Camacho, M. n., Liu, S. Y., Capasso, R. n., Kern, R. C. 2018


    Examine trends in clinical research and levels of evidence related to obstructive sleep apnea (OSA) in the medical literature. Describe the features and trends of OSA research within otolaryngology journals.Retrospective analysis.Review of OSA research articles from 2006, 2011, and 2016 in four leading medical sleep and otolaryngology journals. Level of evidence was graded, and study characteristics were measured.Seven hundred eight total articles were reviewed. OSA articles significantly increased in both number and proportion of total articles in the medical sleep (P < .001) and otolaryngology (P = .004) journals. Surgically focused articles did not significantly increase in either literature. There was no significant difference between medical sleep and otolaryngology literature levels of evidence regarding OSA, and no trend toward higher levels of evidence over time. Medical sleep publications had significantly higher proportions of grant-funded (P < .001) and National Institutes of Health (NIH)-funded (P < .001) publications versus otolaryngology journals. Over time, otolaryngology journals had decreasing numbers of grant-funded and NIH-funded projects.OSA research is increasingly present in medical sleep and otolaryngology literature. Levels of evidence are modest for the two specialties, and have shown no trend toward increasing over time. Concurrently, otolaryngologists are less likely to be grant funded than their medical colleagues, and sleep surgery has stagnated in the studied journals. This study encourages continued efforts to publish high-quality research on OSA. It may also help guide our specialty when setting priorities regarding research funding and support for sleep surgeons.NA Laryngoscope, 2018.

    View details for PubMedID 29314068

  • Integrating the Divided Nasal Cannula Into Routine Polysomnography to Assess Nasal Cycle: Feasibility and Effect on Outcomes JOURNAL OF CLINICAL SLEEP MEDICINE Scapuccin, M., Schneider, L., Rashid, N., Zaghi, S., Rosa, T., Tsuo, Y., Liu, S., Lazarini, P., Capasso, R., Ruoff, C. 2018; 14 (4): 641–50


    Patients suspected to have sleep-disordered breathing underwent an overnight polysomnography using a divided nasal cannula to gain additional information about the nasal cycle during sleep.This was a prospective, observational cohort study replacing the undivided nasal cannula with a divided nasal cannula during routine polysomnography (n = 28).Integration of the divided nasal cannula pressure transducer system into routine polysomnography was easy and affordable. Most patients (89%) demonstrated nasal cycle changes during the test. Nasal cycle changes tended to occur during body position changes (62%) and transitions from non-rapid eye movement sleep to rapid eye movement sleep (41%). The mean nasal cycle duration was 2.5 ± 2.1 hours. Other sleep study metrics did not reveal statistically significant findings in relation to the nasal cycle.Replacing an undivided nasal cannula with a divided nasal cannula is easy to implement, adding another physiologic measure to polysomnography. Although the divided nasal cannula did not significantly affect traditional polysomnographic metrics such as the apnea-hypopnea index or periodic limb movement index based on this small pilot study, we were able to replicate past nasal cycle findings that may be of interest to sleep clinicians and researchers. Given the ease with which the divided nasal cannula can be integrated, we encourage other sleep researchers to investigate the utility of using a divided nasal cannula during polysomnography.

    View details for PubMedID 29609709

    View details for PubMedCentralID PMC5886442

  • Hypopharyngeal Evaluation in Obstructive Sleep Apnea with Awake Flexible Laryngoscopy: Validation and Updates to Cormack-Lehane and Modified Cormack-Lehane Scoring Systems. Clinical otolaryngology : official journal of ENT-UK ; official journal of Netherlands Society for Oto-Rhino-Laryngology & Cervico-Facial Surgery Torre, C., Zaghi, S., Camacho, M., Capasso, R., Liu, S. Y. 2017


    To validate the use of Cormack-Lehane and Modified Cormack-Lehane scoring systems to classify patterns of hypopharyngeal airway visualization seen during awake flexible laryngoscopy among patients with obstructive sleep apnea.Validation study using samples collected from a prospective database.University Medical Center.Data was obtained from a retrospective review of a prospective database of flexible fiberoptic examination recordings in 274 consecutive OSA subjects (Stanford Sleep Medicine/Surgery Clinic).Single still images from awake fiberoptic laryngoscopy examinations of the vocal cords from 90 different patients were presented to 2 experts and 4 novice raters. Raters used two grading systems (Cormack-Lehane scale and Modified Cormack-Lehane) to rate vocal cord visualization. Percent agreement and Cohen's kappa statistical analysis were used to evaluate inter-rater reliability and intra-rater reliability for each grading system. Feedback from the participants was then used to propose updates to further improve upon the existing grading scales for their applicability to awake flexible endoscopy.The Cormack-Lehane and Modified Cormack-Lehane scale both communicate un-obstructed and restricted views of the vocal cords reliably. Compared to the 4-grade scale, however, a modified 5-grade Vocal Cord Grading System allows for better objective communication of common variations in hypopharyngeal airway visualization.We propose a 5-Grade Vocal Cord Grading System that builds upon existing grading systems to allow for efficient and reliable communication of hypopharyngeal airway examination during awake fiberoptic laryngoscopy. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1111/coa.13054

    View details for PubMedID 29280292

  • Restoration of Sleep Architecture after Maxillomandibular Advancement: Success Beyond the Apnea-Hypopnea Index. International journal of oral and maxillofacial surgery Liu, S. Y., Huon, L. K., Ruoff, C., Riley, R. W., Strohl, K. P., Peng, Z. 2017; 46 (12): 1533-1538


    While effects of maxillomandibular advancement (MMA) on respiratory parameters for patients with obstructive sleep apnea (OSA) are well described, effects on sleep architecture before and after MMA are not. A retrospective cohort analysis on sleep architecture was examined in 10 OSA patients who underwent MMA surgery between July 2013 and November 2014, and had prespecified complete polysomnography (PSG) datasets. Sleep stages were examined relative to a Western European population-based control group. All of the respiratory parameters improved significantly post MMA. Rapid eye movement (REM) latency decreased from 178.0±142.8 to 96.6±64.5min (P=0.035). %NREM (non-rapid eye movement)1 (P=0.045) and %WASO (wakefulness after sleep onset) (P=0.006) decreased, while %REM increased (P=0.002) after MMA. WASO decreased from 64.2±57min to 22.4±15.4min (P=0.017). Preoperatively, OSA subjects showed significantly lower sleep efficiency (P=0.016), sleep onset latency (P=0.015), and % REM (P<0.001) than the normative population dataset, while post MMA there was a significant decrease in %NREM1 sleep (P<0.001) and in %WASO (P<0.001). MMA results in a marked decrease in WASO and increase in REM, and to a lesser extent NREM sleep. Patients after MMA show values similar to population controls except for a lower WASO.

    View details for DOI 10.1016/j.ijom.2017.07.001

    View details for PubMedID 28751184

  • Hypoglossal nerve stimulation for treatment of obstructive sleep apnea (OSA): a primer for oral and maxillofacial surgeons MAXILLOFACIAL PLASTIC AND RECONSTRUCTIVE SURGERY Hong, S., Chen, Y., Jung, J., Kwon, Y., Liu, S. 2017; 39 (1)
  • Corrective Nasal Surgery after Maxillomandibular Advancement for Obstructive Sleep Apnea: Experience from 379 Cases. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery Liu, S. Y., Lee, P., Awad, M., Riley, R. W., Zaghi, S. 2017: 194599817695807-?


    Objective Efficacy of maxillomandibular advancement (MMA) in the treatment of obstructive sleep apnea (OSA) is associated with degree of maxillary advancement. Large maxillary advancement leads to profound changes of the nasolabial region. We present the incidence and indications of post-MMA corrective nasal surgery in a large cohort. Study Design Case series with chart review. Setting University medical center. Subjects and Methods A total of 379 subjects with OSA underwent MMA at Stanford Hospital (surgeons: S.Y.L., R.W.R.) from August 1992 to December 2015. Data were collected on age, sex, American Society of Anesthesiologists score, polysomnography parameters, and history of nasal surgery. Primary outcome parameters were the incidence and indications of post-MMA corrective nasal surgery. Results Of 379 subjects, the surgical success rate was 76.3% based on the change in respiratory disturbance index. Seventy-one subjects (18.7%) underwent corrective nasal surgery after MMA, whereas 48 underwent functional nasal surgery and 23 underwent both functional and aesthetic nasal surgery. Lower oxygen saturation nadir and higher baseline respiratory disturbance index were associated with increased likelihood of post-MMA corrective nasal surgery. Conclusion MMA surgical success is associated with degree of maxillary advancement, which is especially significant in patients with severe OSA. Patients must be counseled on its impact in nasal function and aesthetics. Our series, the largest to date to address this question, suggests that the incidence of post-MMA corrective nasal surgery is at least 18.7%. Prospectively, refinement in MMA techniques is needed to minimize postoperative compromise in nasal form and function.

    View details for DOI 10.1177/0194599817695807

    View details for PubMedID 28417661

  • Genial tubercle advancement and genioplasty for obstructive sleep apnea: A systematic review and meta-analysis LARYNGOSCOPE Song, S. A., Chang, E. T., Certal, V., Del Do, M., Zaghi, S., Liu, S. Y., Capasso, R., Camacho, M. 2017; 127 (4): 984-992


    To perform a systematic review and meta-analysis for studies evaluating genioplasty alone, genial tubercle advancement (GTA) alone, and GTA with hyoid surgery (GTA-HS) to treat obstructive sleep apnea (OSA).Ten databases.Three authors searched through November 15, 2015.1,207 studies were screened; 69 were downloaded; and 13 studies met inclusion criteria. A total of 111 patients were included, with 27 standard genioplasty, 10 modified genioplasty, 24 GTA, and 50 GTA-HS patients. For standard genioplasty, the apnea-hypopnea index (AHI) reduced from a mean ± standard deviation (M ± SD) of 18.8 ± 3.8 (95% confidence interval [CI] 17.6, 20.0) to 10.8 ± 4.0 (95% CI 9.5, 12.1) events/hour (relative reduction 43.8%), P value = 0.0001. Genioplasty improved lowest oxygen saturation (LSAT) from 82.3 ± 7.3% (95% CI 80.0, 84.7) to 86.8 ± 5.2% (95% CI 85.1, 88.5), P value = 0.0032. For modified genioplasty AHI increased by 37.3%. For GTA, the AHI reduced from an M ± SD of 37.6 ± 24.2 (95% CI 27.9, 47.3) to 20.4 ± 15.1 (95% CI 14.4, 26.4) events/hour (relative reduction 45.7%), P value = 0.0049. GTA improved LSAT from 83.1 ± 8.3% (95% CI 79.8, 86.4) to 85.5 ± 6.8% (95% CI 82.8, 88.2), P value = 0.2789. For GTA-HS, the AHI reduced from an M ± SD of 34.5 ± 22.1 (95% CI 28.4, 40.6) to 15.3 ± 17.6 (95% CI 10.4, 20.2) events/hour (relative reduction 55.7%), P value < 0.0001; GTA-HS improved LSAT from 80.1 ± 16.6% (95% CI 75.5, 84.7) to 88.3 ± 6.9% (95% CI 86.4, 90.2), P value = 0.0017.Standard genioplasty, GTA and GTA-HS can improve OSA outcomes such as AHI and LSAT. Given the low number of studies, these procedures remain as an area for additional OSA research. Laryngoscope, 2016.

    View details for DOI 10.1002/lary.26218

    View details for Web of Science ID 000397572700043

  • The state of academic sleep surgery: A survey of United States residency and fellowship programs. Laryngoscope Gouveia, C. J., Kern, R. C., Liu, S. Y., Capasso, R. 2017


    Our objectives were to describe otolaryngology residency programs' experience in and attitudes toward sleep surgery, and describe current otolaryngology sleep fellowships and their impact on future academic practice.E-mail survey.A survey was e-mailed to program directors of 106 Accreditation Council for Graduate Medical Education-accredited otolaryngology residencies assessing resident sleep medicine experience, program satisfaction, and impact of sleep faculty. A separate survey was sent to directors of the seven sleep medicine otolaryngology fellowships. Frequency of graduates pursuing academic careers was examined.Forty-six (43.4%) residency programs responded. Thirty-one (67.4%) have a faculty member with any time spent practicing sleep medicine or surgery. Nineteen (41.3%) have a faculty member with >50% dedicated sleep practice and/or who is board certified in sleep medicine. These programs were significantly more likely to respond "extremely" or "very" satisfied with resident sleep exposure than those without (P < .001). Most programs (69.6%) "strongly agreed" or "agreed" their program would benefit from a dedicated sleep surgeon; there was no significant difference in response rates between programs already with and those without dedicated sleep faculty. All fellowship directors responded. In the past 5 years these programs have trained 11 total fellows. Ten (90.9%) have remained in academic practice.There is significantly increased satisfaction in resident sleep education at otolaryngology programs with dedicated sleep providers. Concurrently, there is strong program interest in sleep surgeons' involvement in resident training. Sleep fellowships are producing surgeons who pursue academic careers. This study provides support to training fellowship-specialized sleep surgeons and encouraging otolaryngology sleep faculty.NA Laryngoscope, 2017.

    View details for DOI 10.1002/lary.26572

    View details for PubMedID 28349537

  • Transpalatal advancement pharyngoplasty for obstructive sleep apnea: a systematic review and meta-analysis. European archives of oto-rhino-laryngology Volner, K., Dunn, B., Chang, E. T., Song, S. A., Liu, S. Y., Brietzke, S. E., O'Connor, P., Camacho, M. 2017; 274 (3): 1197-1203


    The objective is to determine if apnea-hypopnea index (AHI) and lowest oxygen saturation (LSAT) improve after transpalatal advancement pharyngoplasty (TPAP) with obstructive sleep apnea (OSA) in adults, using a systematic review and meta-analysis. Nine databases, including PubMed/MEDLINE, were searched through April 1, 2016. All studies that included patients who underwent TPAP alone were included in this analysis. Fifty-six studies were potentially relevant, 37 were downloaded and five studies met criteria with 199 patients (age: 42.5 ± 9.7 years and body mass index: 29.0 ± 4.0 kg/m(2)). The grand mean (M) and standard deviation (SD) for AHI (199 patients) pre and post-TPAP decreased from 54.6 ± 23.0 [95 % CI 51.4, 57.8] to 19.2 ± 16.8 [95 % CI 16.9, 21.5] events/h (relative reduction: 64.8 %). Random effects modeling demonstrated a mean difference (MD) of -36.3 [95 % CI -48.5, -24.1], overall effect Z = 5.8 (p < 0.00001), and I (2) = 85 % (significant inconsistency). The standardized mean difference (SMD) for TPAP demonstrated a large magnitude of effect for AHI -1.76 [95 % CI -2.4, -1.1]. For LSAT (70 patients), the pre and post-TPAP M ± SD improved from 81.9 ± 8.1 [95 % CI 80.0, 83.8] to 85.4 ± 6.9 [95 % CI 83.8, 87.0], with a MD of 3.55, overall effect Z = 1.79 (p = 0.07). Thus far, few studies have evaluated transpalatal advancement pharyngoplasty; therefore, we recommend additional studies, especially prospective studies. Research comparing TPAP to pharyngoplasty procedures without palatal advancement would help determine the optimal role for this procedure.

    View details for DOI 10.1007/s00405-016-4121-3

    View details for PubMedID 27289234

  • Continuing the Original Stanford Sleep Surgery Protocol From Upper Airway Reconstruction to Upper Airway Stimulation: Our First Successful Case. Journal of oral and maxillofacial surgery Liu, S. Y., Riley, R. W. 2017


    In 1993, a surgical protocol for dynamic upper airway reconstruction in patients with obstructive sleep apnea (OSA) was published, and it became commonly known as the Stanford phase 1 and 2 sleep surgery protocol. It served as a platform on which research and clinical studies have continued to perfect the surgical care of patients with OSA. However, relapse is inevitable in a chronic condition such as OSA, and a subset of previously cured surgical patients return with complaints of excessive daytime sleepiness. This report describes a patient who was successfully treated with phase 1 and 2 operations more than a decade previously. He returned at 65 years of age with relapse of moderate OSA, and after workup with polysomnography and drug-induced sleep endoscopy, he underwent upper airway stimulation of the hypoglossal nerve that resulted in cure of OSA. This case shows why upper airway stimulation is an appropriate option for patients with OSA and previously successful maxillomandibular advancement.

    View details for DOI 10.1016/j.joms.2017.02.008

    View details for PubMedID 28294946

  • Impact of Continuous Positive Airway Pressure in Patients with Obstructive Sleep Apnea During Drug Induced Sleep Endoscopy. Clinical otolaryngology Torre, C., Liu, S. Y., Kushida, C. A., Nekhendzy, V., Huon, L., Capasso, R. 2017


    The primary objective of the study was to understand the differential impact of Continuous Positive Airway Pressure (CPAP) on the location, degree, and pattern of airway collapse in Obstructive Sleep Apnea (OSA) patients utilizing Drug Induced Sleep Endoscopy (DISE).Non-randomized trial.University Medical Center.15 consecutive OSA patients undergoing DISE.The patterns of airway collapse were videorecorded at baseline and under differential application of nasal CPAP (nCPAP) at 5,10, and 15 cm H2 O. For each modality, the pattern and degree of airway collapse were analyzed by three independent observers using the Velum, Oropharynx, Tongue Base, Epiglottis (VOTE) classification system.The modest nCPAP pressures (10cm H2 O) had the greatest impact on the lateral walls of the pharynx, followed by the palatal region. The collapsibility of the tongue base and epiglottis demonstrated significant resistance to nCPAP application, which was overcome by increasing nCPAP to 15 cm H2 O. Compared to 5 cm H2 O, nCPAP pressures of 10 and 15 cm H2 O improved complete collapse at least at one level of the upper airway (p = 0.016 and 0.001, respectively). Increased nCPAP pressures also led to changes in the configuration of airway collapse at the level of the velum.The differential nCPAP effects observed in this study may help to understand some of the mechanisms responsible for inadequate patient response and poor nCPAP compliance. The use of DISE in combination with CPAP may serve as a first step in optimizing patients that failed to adapt to treatment with CPAP. This approach can help the physician identify patterns of airway collapse that may require varying pressures different from the one the patient is using, as well as anatomical factors that may be corrected to help with compliance. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1111/coa.12851

    View details for PubMedID 28207995

  • Laser Assisted Uvulopalatoplasty (LAUP) for Obstructive Sleep Apnea: A Systematic Review and Meta-Analysis. Sleep Camacho, M., Nesbitt, N. B., Lambert, E., Song, S. A., Chang, E. T., Yung Liu, S., Kushida, C. A., Zaghi, S. 2017


    Laser-assisted uvulopalatoplasty (LAUP) has been used as treatment for obstructive sleep apnea (OSA). The objective of this study was to perform a systematic review and meta-analysis for LAUP alone as treatment for OSA in adults.Three authors searched five databases (including PubMed/MEDLINE) from inception through October 30, 2016 for peer-reviewed studies, with any design/language. A study quality assessment tool was used. The PRISMA statement was followed. A meta-analysis was performed.Twenty-three adult studies (717 patients) reported outcomes (age: 50 ± 9 years, body mass index: 29 ± 4 kg/m2). The pre- and post-LAUP means (M) ± standard deviations (SDs) for apnea-hypopnea index (AHI) were 28 ± 13 and 19 ± 12 events/h (32% reduction). Random effects modeling for 519 patients demonstrated an AHI mean difference (MD) of -6.56 [95% CI -10.14, -2.97] events/h. Individual patient data analyses demonstrate a 23% success rate (≥50% reduction in AHI and <20 events/h) and an 8% cure rate. Additionally, 44% of patients had worsening of their AHI after LAUP. Lowest oxygen saturation (LSAT) improved from a M ± SD of 80 ± 8% to 82 ± 7%. A limitation is that most studies were case series studies and only two were randomized controlled trials.In this meta-analysis, LAUP reduced AHI by 32% among all patients; while the LSAT only changed minimally. Individual data demonstrated a success rate of 23%, cure rate of 8%, and worsening of the AHI among 44% of patients. We recommend that LAUP be performed with caution or not performed at all given the unfavorable results of currently published studies.

    View details for DOI 10.1093/sleep/zsx004

    View details for PubMedID 28201808

  • Comparison of functional outcomes and patient-reported satisfaction between titanium and absorbable plates and screws for fixation of mandibular fractures: A one-year prospective study. Journal of cranio-maxillo-facial surgery : official publication of the European Association for Cranio-Maxillo-Facial Surgery Leno, M. B., Liu, S. Y., Chen, C. T., Liao, H. T. 2017


    The aim of this study is to compare the 1-year functional outcomes and patient-reported satisfaction in treating mandibular fractures between resorbable and titanium fixation devices.A 1-year prospective study was conducted; 41 consecutive patients presenting with mandibular fractures were included. A resorbable system was used in 21 patients, while in 20 patients a titanium fixation device was used. Functional outcome was evaluated objectively at several time points (2, 4 and 6 weeks, 3 and 6 months, and 1 year after surgery). Bite forces over molars and incisors, mouth opening distance, occlusal status, operation time, fee for implants, bone healing and plate-associated complications were evaluated. Functional and overall satisfaction was measured by patients themselves subjectively.A statistical difference was found only in maximal mouth opening and molar bite force, both greater for the titanium group in the 2-week time point, achieving comparable measurements in subsequent ones. This coincides with the patient-reported statistically lower satisfaction rates. The cost of the resorbable device was nearly 3 times more expensive than the titanium devices.Resorbable fixation can achieve stability of bone healing at 1 year postoperatively, with functional and satisfaction outcomes comparable to those associated with titanium hardware from the fourth week postoperatively, while yielding unique advantages.

    View details for DOI 10.1016/j.jcms.2017.01.034

    View details for PubMedID 28318918

  • Sleep Surgery in the Elderly. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery Gouveia, C. J., Cramer, J. D., Liu, S. Y., Capasso, R. 2017: 194599817691475-?


    Objective Assess the frequency and nature of postoperative complications following sleep surgery. Examine these issues specifically in elderly patients to provide guidance for their perioperative care. Study Design Retrospective cohort study. Setting American College of Surgeons National Surgical Quality Improvement Program. Methods We identified patients with obstructive sleep apnea undergoing sleep surgery procedures from 2006 to 2013 in the American College of Surgeons National Surgical Quality Improvement Program, a multi-institutional outcomes program designed to improve surgical quality. We analyzed patients by comparing age groups: <65 and ≥65 years. Summary data were analyzed, and multivariate regression was used to adjust for patient characteristics, comorbidities, and surgical procedure. Results We identified 2230 patients who had sleep surgery, which included 2123 patients <65 years old and 107 patients ≥65 years old. Elderly patients were significantly more likely to have hypertension requiring medication ( P < .001) and higher American Society of Anesthesiologists scores ( P < .001). There were no significant differences in the rates of nasal ( P = .87), palate ( P = .59), tongue base ( P = .73), and multilevel ( P = .95) surgery being performed on both groups of patients. Elderly patients had higher rates of wound complications and urinary tract infections as compared with younger patients. On multivariate analysis, age ≥65 was significantly associated with complications from sleep surgery (odds ratio, 2.35; 95% CI, 1.04-5.35). Conclusion Elderly patients undergoing sleep surgery have increased postoperative complication risk as compared with younger patients treated similarly. This information can help direct quality improvement efforts in the care of older patients.

    View details for DOI 10.1177/0194599817691475

    View details for PubMedID 28195824

  • Tongue retaining devices for obstructive sleep apnea: A systematic review and meta-analysis. American journal of otolaryngology Chang, E. T., Fernandez-Salvador, C., Giambo, J., Nesbitt, B., Liu, S. Y., Capasso, R., Kushida, C. A., Camacho, M. 2017


    Tongue Retaining Devices (TRD) anteriorly displace the tongue with suction forces while patients sleep. TRD provide a non-surgical treatment option for patients with Obstructive Sleep Apnea (OSA). Our objective was to conduct a systematic review of the international literature for TRD outcomes as treatment for OSA.Three authors independently and systematically searched four databases (including PubMed/MEDLINE) through June 26, 2016. We followed guidelines set within the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).Sixteen studies with 242 patients met criteria. The overall means±standard deviations (M±SD) for apnea-hypopnea index (AHI) decreased from 33.6±21.1/h to 15.8±16.0/h (53% reduction). Seven studies (81 patients) reported lowest oxygen saturation (LSAT), which improved from 79.8±17.5% to 83.9±8.6%. Four studies (93 patients) reported Epworth sleepiness scale (ESS), which decreased from 10.8±4.8 to 8.2±4.5, p <0.0001. Four studies (31 patients) reported Oxygen Desaturation Index (ODI) which decreased from 29.6±32.1 to 12.9±8.7, a 56.4% reduction.Current international literature demonstrates that tongue retaining devices reduce apnea-hypopnea index by 53%, increase lowest oxygen saturation by 4.1 oxygen saturation points, decrease oxygen desaturation index by 56% and decrease Epworth sleepiness scale scores by 2.8 points. Tongue retaining devices provide a statistically effective alternative treatment option for obstructive sleep apnea.

    View details for DOI 10.1016/j.amjoto.2017.01.006

    View details for PubMedID 28237516

  • Toward a functional definition of ankyloglossia: validating current grading scales for lingual frenulum length and tongue mobility in 1052 subjects. Sleep & breathing = Schlaf & Atmung Yoon, A., Zaghi, S., Weitzman, R., Ha, S., Law, C. S., Guilleminault, C., Liu, S. Y. 2017


    Alterations of the lingual frenulum may contribute to oromyofacial dysfunction, speech and swallowing impediments, underdevelopment of the maxillofacial skeleton, and even predispose to sleep breathing disorder. This study aims to assess the utility of existing instruments for evaluation of restricted tongue mobility, describe normal and abnormal ranges of tongue mobility, and provide evidence in support of a reliable and efficient measure of tongue mobility.A prospective cohort study of 1052 consecutive patients was evaluated during a 3-month period. Age, gender, ethnicity, height, weight, BMI, maximal interincisal mouth opening (MIO), mouth opening with tongue tip to maxillary incisive papillae at roof of mouth (MOTTIP), Kotlow's free-tongue measurement, and presence of severe tongue-tie were recorded. Secondary outcome measures include tongue range of motion deficit (TRMD, difference between MIO and MOTTIP) and tongue range of motion ratio (TRMR, ratio of MOTTIP to MIO).Results indicate that MIO is dependent on age and height; MOTTIP and TRMD are dependent on MIO; Kotlow's free-tongue measurement is an independent measure of free-tongue length and tongue mobility. TRMR is the only independent measurement of tongue mobility that is directly associated with restrictions in tongue function.We propose the use of tongue range of motion ratio as an initial screening tool to assess for restrictions in tongue mobility. "Functional" ankyloglossia can thus be defined and treatment effects followed objectively by using the proposed grading scale: grade 1: tongue range of motion ratio is >80%, grade 2 50-80%, grade 3 < 50%, grade 4 < 25%.

    View details for DOI 10.1007/s11325-016-1452-7

    View details for PubMedID 28097623

  • An Accurate Method of Designing and Performing Individual-Specific Genioglossus Advancement OTOLARYNGOLOGY-HEAD AND NECK SURGERY Liu, S. Y., Huon, L., Zaghi, S., Riley, R., Torre, C. 2017; 156 (1): 194-197


    There is too much individual patient variation in mandibular anatomy for any single described genioglossus advancement technique to be used consistently. Virtual surgical planning allows surgeons to design genioglossus osteotomy that captures the structures of interest. Intraoperative osteotomy and positioning guides mitigate known risks of the procedure while maximizing the reproducibility and efficacy of the procedure. In this report, we demonstrate the protocol step by step as it had been used on 10 patients, and we highlight 3 clinical scenarios that exemplify its utility.

    View details for DOI 10.1177/0194599816670366

    View details for PubMedID 28045634

  • Mandibular advancement for adult obstructive sleep apnea: A systematic review and meta-analysis. Journal of cranio-maxillo-facial surgery : official publication of the European Association for Cranio-Maxillo-Facial Surgery Noller, M. W., Guilleminault, C. n., Gouveia, C. J., Mack, D. n., Vivian, C. n., Abdullatif, J. n., Mangili, S. n., Liu, S. Y., Zaghi, S. n., Camacho, M. n. 2017; 45 (12): 2035–40


    Patients with mandibular insufficiency can be predisposed to obstructive sleep apnea (OSA). The objective of this study was to systematically review the international literature for mandibular advancement surgeries (MAS) as treatment for adult OSA, and then to perform a meta-analysis.Four authors searched five databases from the inception of each database through April 5, 2017. The PRISMA statement was followed.972 studies were screened, 84 were downloaded, and 11 (57 patients) met criteria. In patients with mandibular insufficiency, MAS reduced apnea-hypopnea index (AHI) (50 patients) from 45.9 ± 24.7 to 6.2 ± 10.4 events/h (87% decrease). The lowest oxygen saturation (LSAT) (55 patients) increased from 71.9 ± 14.6% to 89.0 ± 11.0%. The AHI mean difference was -34.8 events/h [95% CI -43.9, -25.8]. The AHI standardized mean difference was -1.8 [95% CI -2.5, -1.2] (indicating a large magnitude of effect). Surgical cure was seen in 75% of those with >16 mm of mandibular advancement vs. 35% of those with <16 mm of advancement [Odds Ratio 5.5; 95% CI 1.06-28.4; Chi Square p = 0.035].The current literature supports isolated mandibular advancement as an efficacious treatment modality for adult OSA in select patients with mandibular insufficiency.

    View details for DOI 10.1016/j.jcms.2017.10.006

    View details for PubMedID 29113702

  • Ankyloglossia as a risk factor for maxillary hypoplasia and soft palate elongation: A functional - morphological study. Orthodontics & craniofacial research Yoon, A. J., Zaghi, S. n., Ha, S. n., Law, C. S., Guilleminault, C. n., Liu, S. Y. 2017; 20 (4): 237–44


    To characterize associations between restricted tongue mobility and maxillofacial development.Cross-sectional cohort study of 302 consecutive subjects from an orthodontic practice.Tongue mobility (measured with tongue range of motion ratio [TRMR] and Kotlow free tongue measurement) was correlated with measurements of the maxillofacial skeleton obtained from dental casts and cephalometric radiographs.Tongue range of motion ratio and Kotlow measures of restricted tongue mobility were associated with (i) ratio of maxillary intercanine width to canine arch length, (ii) ratio of maxillary intermolar width to canine arch length and (iii) soft palate length. Restricted tongue mobility was not associated with hyoid bone position or Angle's skeletal classification.Restricted tongue mobility was associated with narrowing of the maxillary arch and elongation of the soft palate in this study. These findings suggest that variations in tongue mobility may affect maxillofacial development.

    View details for PubMedID 28994495

  • Hypoglossal nerve stimulation for treatment of obstructive sleep apnea (OSA): a primer for oral and maxillofacial surgeons. Maxillofacial plastic and reconstructive surgery Hong, S. O., Chen, Y. F., Jung, J. n., Kwon, Y. D., Liu, S. Y. 2017; 39 (1): 27


    The prevalence of obstructive sleep apnea (OSA) is estimated to be 1-5% of the adult population world-wide, and in Korea, it is reported at 4.5% of men and 3.2% of women (Age 40 to 69 years old). Active treatment of OSA is associated with decrease in insulin resistance, cardiovascular disease, psychosocial problems, and mortality. Surgical treatment of OSA has evolved in the era of neuromodulation with the advent of hypoglossal nerve stimulation (HGNS). We share this review of HGNS with our maxillofacial surgical colleagues to expand the scope of surgical care for OSA.

    View details for PubMedID 29018786

  • Static craniofacial measurements and dynamic airway collapse patterns associated with severe obstructive sleep apnoea: a sleep MRI study CLINICAL OTOLARYNGOLOGY Liu, S. Y., Huon, L., Lo, M., Chang, Y., Capasso, R., Chen, Y., Shih, T. T., Wang, P. 2016; 41 (6): 700-706


    Using sleep MRI, we aimed to identify static craniofacial measurements and dynamic upper airway collapse patterns associated with severe obstructive sleep apnea (OSA) during natural sleep in age and BMI matched patients.Nested case-control study.Sleep MRI images (3.0 Tesla scanner) and synchronized acoustic recording were used to observe patterns of dynamic airway collapse in subjects with mild and severe OSA. Mid-sagittal images were also used for static craniofacial measurements.15 male subjects with severe OSA (mean AHI 70.3±23 events/hour) were matched by age and BMI to 15 subjects with mild OSA (mean AHI 7.8±1.4 events/hour). Subjects were selected from a consecutive sleep MRI study cohort.Static craniofacial measurements selected a priori included measurements that represent maxillomandibular relationships and airway morphology. Axial, sagittal, and coronal views of the airway were rated for dynamic collapse at retropalatal, retroglossal, and lateral pharyngeal wall regions by blinded reviewers. Bivariate analysis was used to correlate measures associated with severity of OSA using AHI. Statistical significance was set at p < 0.01.Lateral pharyngeal wall collapse from dynamic sleep MRI (ß=51.8, p<0.001) and upper airway length from static MRI images (ß=27.2, p<0.001) positively correlated with severity of OSA.Lateral pharyngeal wall collapse and upper airway length are significantly associated with severe OSA based on sleep MRI. Assessment of these markers can be readily translated to routine clinical practice, and their identification may direct targeted surgical treatment. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1111/coa.12598

    View details for PubMedID 26615985

  • The association between ophthalmologic diseases and obstructive sleep apnea: a systematic review and meta-analysis SLEEP AND BREATHING Huon, L., Liu, S. Y., Camacho, M., Guilleminault, C. 2016; 20 (4): 1145-1154


    The purpose of this study was to evaluate the association between obstructive sleep apnea (OSA) and ophthalmologic diseases, specifically glaucoma, nonarteritic anterior ischemic optic neuropathy (NAION), retinal vein occlusion (RVO), central serous chorioretinopathy (CSR), and floppy eyelid syndrome (FES), by performing a systematic review and meta-analysis of published studies.PubMed, Embase, and Scopus databases were searched for observational studies on OSA and its association with select ophthalmologic diseases. Data was pooled for random-effects modeling. The association between OSA and ophthalmologic diseases was summarized using an estimated pooled odds ratio with a 95 % confidence interval.Relative to non-OSA subjects, OSA subjects have increased odds of diagnosis with glaucoma (pooled odds ratio (OR) = 1.242; P < 0.001) and floppy eyelids syndrome (pooled OR = 4.157; P < 0.001). In reverse, the overall pooled OR for OSA was 1.746 (P = 0.002) in the glaucoma group, 3.126 (P = 0.000) in the NAION group, and 2.019 (P = 0.028) in the CSR group. For RVO, one study with 5965 OSA patients and 29,669 controls demonstrated a 1.94-fold odds increase in OSA patients.Our results suggest significant associations between OSA and glaucoma, NAION, CSR, and FES. Screening for OSA should be considered in patients with glaucoma, NAION, CSR, or FES.

    View details for DOI 10.1007/s11325-016-1358-4

    View details for PubMedID 27230013

  • Dynamic upper airway collapse observed from sleep MRI: BMI-matched severe and mild OSA patients EUROPEAN ARCHIVES OF OTO-RHINO-LARYNGOLOGY Huon, L., Liu, S. Y., Shih, T. T., Chen, Y., Lo, M., Wang, P. 2016; 273 (11): 4021-4026


    Dynamic magnetic resonance imaging (MRI) allows real-time characterization of upper airway collapse in sleeping subjects with obstructive sleep apnea (OSA). The aim of our study was to use sleep MRI to compare differences in upper airway collapse sites between BMI-matched subjects with mild OSA and severe OSA. This is a prospective, nested case-control study using dynamic sleep MRI to compare 15 severe OSA subjects (AHI >40) and 15 mild OSA (AHI <10) subjects, who were matched for BMI. Upper airway imaging was performed on sleeping subjects in a 3.0 T MRI scanner. Sleep MRI movies were used by blinded reviewers to identify retropalatal (RP), retroglossal (RG), and lateral pharyngeal wall (LPW) airway collapse. Mean AHI in the severe OSA group was 70.3 ± 23 events/h, and in the mild group was 7.8 ± 1 events/h (p < 0.001). All mild and severe OSA subjects demonstrated retropalatal airway collapse. Eighty percent in the mild group showed single-level RP collapse (p < 0.001). All subjects in the severe group showed multi-level collapse: RP + LPW (n = 9), RP + RG + LPW (n = 6). All severe OSA subjects showed LPW collapse, as compared with three subjects in the mild group (p < 0.001). LPW collapse was positively associated with AHI in simple regression analysis (β = 51.8, p < 0.001). In conclusion, severe OSA patients present with more lateral pharyngeal wall collapse as compared to BMI-matched mild OSA patients.

    View details for DOI 10.1007/s00405-016-4131-1

    View details for PubMedID 27276991

  • Subtypes of Maxillomandibular Advancement Surgery for Patients With Obstructive Sleep Apnea JOURNAL OF CRANIOFACIAL SURGERY Lee, W., Hwang, D., Liu, S. Y., Kim, S. 2016; 27 (8): 1965-1970


    Maxillomandibular advancement (MMA) surgery, which is the most effective treatment modality for patients with moderate-to-severe obstructive sleep apnea with apparent skeletal discrepancies, has been modified in conjunction with segmental osteotomies, counterclockwise rotation of maxillomandibular complex, and other adjunctive procedures. However, any single type of MMA could not treat or cure all the patients with obstructive sleep apnea showing different dentofacial and pharyngeal patterns. We aimed to suggest critical decision factors for the selective application of MMA subtypes, categorized as straight MMA with genioplasty, rotational MMA, segmental MMA, and segmental-rotational MMA, in the surgical treatment objective process: anteroposterior position of maxilla, upper lip projection, overjet, lower incisor inclination as sagittal factors, and upper incisor exposure and occlusal plane angle as vertical factors. This case series deserves a clinical basis on the way of case-by-case application of the optimal MMA subtype based on the successful treatment outcomes with short-term stability.

    View details for DOI 10.1097/SCS.0000000000003027

    View details for PubMedID 28005735

  • Inferior alveolar nerve hemangioma. Laryngoscope Vaezeafshar, R., Liu, S. Y., Sidell, D. 2016; 126 (9): 2168-2170


    A 14-year-old male presented with lower lip numbness and a slowly enlarging mandibular mass. Computed tomography demonstrated an expansile lesion centered in the marrow space of the left mandibular body, extending along the course of the inferior alveolar nerve (IAN), and expanding the mental foramen. Preoperative diagnosis was consistent with an IAN schwannoma. Surgical planning was performed using PROPLAN CMF software. The lesion was approached via a sagittal split osteotomy and excised en bloc with the IAN. Final pathology demonstrated a capillary hemangioma originating from the inferior alveolar nerve. Based on a detailed PubMed search, this is the first capillary hemangioma of the inferior alveolar nerve reported in the literature.NA Laryngoscope, 2016.

    View details for DOI 10.1002/lary.25869

    View details for PubMedID 26863892

  • Genial tubercle advancement and genioplasty for obstructive sleep apnea: A systematic review and meta-analysis. Laryngoscope Song, S. A., Chang, E. T., Certal, V., Del Do, M., Zaghi, S., Liu, S. Y., Capasso, R., Camacho, M. 2016


    To perform a systematic review and meta-analysis for studies evaluating genioplasty alone, genial tubercle advancement (GTA) alone, and GTA with hyoid surgery (GTA-HS) to treat obstructive sleep apnea (OSA).Ten databases.Three authors searched through November 15, 2015.1,207 studies were screened; 69 were downloaded; and 13 studies met inclusion criteria. A total of 111 patients were included, with 27 standard genioplasty, 10 modified genioplasty, 24 GTA, and 50 GTA-HS patients. For standard genioplasty, the apnea-hypopnea index (AHI) reduced from a mean ± standard deviation (M ± SD) of 18.8 ± 3.8 (95% confidence interval [CI] 17.6, 20.0) to 10.8 ± 4.0 (95% CI 9.5, 12.1) events/hour (relative reduction 43.8%), P value = 0.0001. Genioplasty improved lowest oxygen saturation (LSAT) from 82.3 ± 7.3% (95% CI 80.0, 84.7) to 86.8 ± 5.2% (95% CI 85.1, 88.5), P value = 0.0032. For modified genioplasty AHI increased by 37.3%. For GTA, the AHI reduced from an M ± SD of 37.6 ± 24.2 (95% CI 27.9, 47.3) to 20.4 ± 15.1 (95% CI 14.4, 26.4) events/hour (relative reduction 45.7%), P value = 0.0049. GTA improved LSAT from 83.1 ± 8.3% (95% CI 79.8, 86.4) to 85.5 ± 6.8% (95% CI 82.8, 88.2), P value = 0.2789. For GTA-HS, the AHI reduced from an M ± SD of 34.5 ± 22.1 (95% CI 28.4, 40.6) to 15.3 ± 17.6 (95% CI 10.4, 20.2) events/hour (relative reduction 55.7%), P value < 0.0001; GTA-HS improved LSAT from 80.1 ± 16.6% (95% CI 75.5, 84.7) to 88.3 ± 6.9% (95% CI 86.4, 90.2), P value = 0.0017.Standard genioplasty, GTA and GTA-HS can improve OSA outcomes such as AHI and LSAT. Given the low number of studies, these procedures remain as an area for additional OSA research. Laryngoscope, 2016.

    View details for DOI 10.1002/lary.26218

    View details for PubMedID 27546467

  • Supraglottoplasty for laryngomalacia with obstructive sleep apnea: A systematic review and meta-analysis LARYNGOSCOPE Camacho, M., Dunn, B., Torre, C., Sasaki, J., Gonzales, R., Liu, S. Y., Chan, D. K., Certal, V., Cable, B. B. 2016; 126 (5): 1246-1255


    To determine if apnea-hypopnea index (AHI) and lowest oxygen saturation (LSAT) improve following isolated supraglottoplasty for laryngomalacia with obstructive sleep apnea (OSA) in children.Systematic review and meta-analysis.Nine databases, including PubMed/MEDLINE, were searched through September 30, 2015.A total of 517 studies were screened; 57 were reviewed; and 13 met criteria. One hundred thirty-eight patients were included (age range: 1 month-12.6 years). Sixty-four patients had sleep exclusive laryngomalacia, and in these patients: 1) AHI decreased from a mean (M) ± standard deviation (SD) of 14.0 ± 16.5 (95% confidence interval [CI] 10.0, 18.0) to 3.3 ± 4.0 (95% CI 2.4, 4.4) events/hour (relative reduction: 76.4% [95% CI 53.6, 106.4]); 2) LSAT improved from a M ± SD of 84.8 ± 8.4% (95% CI 82.8, 86.8) to 87.6 ± 4.4% (95% CI 86.6, 88.8); 3) standardized mean differences (SMD) demonstrated a small effect for LSAT and a large effect for AHI; and 4) cure (AHI < 1 event/hour) was 10.5% (19 patients with individual data). Seventy-four patients had congenital laryngomalacia, and in these patients: 1) AHI decreased from a M ± SD of 20.4 ± 23.9 (95% CI 12.8, 28.0) to 4.0 ± 4.5 (95% CI 2.6, 5.4) events/hour (relative reduction: 80.4% [95% CI 46.6, 107.4]); 2) LSAT improved from a M ± SD of 74.5 ± 11.9% (95% CI 70.9, 78.1) to 88.4 ± 6.6% (95% CI 86.4, 90.4); 3) SMD demonstrated a large effect for both AHI and LSAT; and 4) cure was 26.5% (38 patients with individual data).Supraglottoplasty has improved AHI and LSAT in children with OSA and either sleep exclusive laryngomalacia or congenital laryngomalacia; however, the majority of them are not cured. Laryngoscope, 2015.

    View details for DOI 10.1002/lary.25827

    View details for Web of Science ID 000374769400046

    View details for PubMedID 26691675

  • Epiglottis collapse in adult obstructive sleep apnea: A systematic review. Laryngoscope Torre, C., Camacho, M., Liu, S. Y., Huon, L., Capasso, R. 2016; 126 (2): 515-523


    To systematically review the international literature evaluating the role of the epiglottis in snoring and obstructive sleep apnea and to explore possible treatment options available.PubMed, Scopus, Embase, Google Scholar, Book Citation Index-Science, CINAHL, Conference Proceedings Citation Index-Science, The Cochrane Collaboration Databases, and Web of Science.The searches were performed from the first year of each database through March 5, 2015.Fourteen studies about the prevalence of epiglottis collapse in obstructive sleep apnea (OSA) were found. Most involved drug-induced sleep endoscopy studies that indirectly reported their findings about epiglottis collapse. The data suggests that the prevalence of epiglottis collapse in OSA is higher than previously described. The epiglottis has been implicated in 12% of cases of snoring, and sound originating from it has a higher pitch than palatal snoring. Continuous positive pressure (CPAP) surgery and positional therapy in the treatment of epiglottis collapse were also considered. Lateral position of the head may reduce the frequency of epiglottis collapse. With regard to CPAP, available reports suggest that it may accentuate collapse of the epiglottis. Surgery may help reduce snoring in some patients with a lax epiglottis and improve OSA in patients undergoing multilevel surgery.Knowledge regarding the role of the epiglottis in adult OSA and snoring patients is limited. The prevalence of this phenomenon in OSA seems to be greater than previously reported, and more research is needed to understand its role in OSA and the best way to treat it.NA. Laryngoscope, 2015.

    View details for DOI 10.1002/lary.25589

    View details for PubMedID 26371602

  • Hyoid surgery alone for obstructive sleep apnea: A systematic review and meta-analysis. The Laryngoscope Song, S. A., Wei, J. M., Buttram, J. n., Tolisano, A. M., Chang, E. T., Liu, S. Y., Certal, V. n., Camacho, M. n. 2016


    The primary objective was to determine if sleep study variables (e.g., apnea-hypopnea index [AHI] and lowest oxygen saturation) and quantitative sleepiness data improve following isolated hyoid surgery for obstructive sleep apnea (OSA).Systematic review and meta-analysis.Nine databases, including PubMed, were searched through September 5, 2015.Four hundred ninety-eight studies were screened, 64 were reviewed, and nine studies met inclusion criteria. A total of 101 patients were identified who underwent hyoid surgery alone for treatment of OSA. Subanalyses were performed for: 1) type of surgery, 2) primary versus secondary hyoid surgery, 3) positional versus nonpositional OSA, 4) age, and 5) body mass index. In patients undergoing isolated hyoid surgery, the AHI decreased from a mean ± standard deviation of 37.3 ± 21.1 (95% confidence interval [CI]: 33.1, 41.5) to 23.0 ± 18.6 (95% CI: 19.3, 26.7) events/hour, which correspond to a 38.3% reduction (P < .0001). AHI reduced by 38.3% for hyoid myotomy with suspension, by 50.7% for hyothyroidopexy, and by 7.1% for hyoid expansion. The Epworth Sleepiness Scale decreased by 3.2 points from 10.3 ± 4.9 (95% CI: 8.8, 11.8) to 7.1 ± 4.2 (95% CI: 5.8, 8.4; P = .0027).Isolated hyoid surgery has reduced OSA severity and improved sleepiness in adults. Hyothyroidopexy provided a 50.7% reduction in AHI, followed by hyoid myotomy with suspension (38.3% reduction in AHI) and hyoid expansion (7.1% reduction in AHI). The current literature lacks high-quality evidence with regard to hyoid surgery, and additional studies are needed to further elucidate the effect of hyoid surgery in OSA.NA Laryngoscope, 2015.

    View details for DOI 10.1002/lary.25847

    View details for PubMedID 26801005

  • Static hyoid position and dynamic lateral pharyngeal wall collapse predict OSA severity: Observations based on sleep MRI Huon, L., Liu, S., Liu, T., Cho, G., Wang, P. ELSEVIER. 2015: S186
  • Maxillomandibular advancement - The name tells half the story Cho, G., Huon, L., Liu, S. ELSEVIER. 2015: S17-S18
  • Lateral pharyngeal wall collapse associated with hypoxemia in obstructive sleep apnea. Laryngoscope Lan, M., Liu, S. Y., Lan, M., Modi, R., Capasso, R. 2015; 125 (10): 2408-2412


    Review drug-induced sleep endoscopy (DISE) findings and correlate the patterns of airway collapse with body mass index (BMI) and objective sleep study respiratory variables, with particular emphasis on oxygen desaturation variables.Retrospective chart review.From January 2010 to March 2014, 64 patients underwent DISE, and its findings were registered using the VOTE (velum, oropharynx, tongue base, epiglottis) classification system. Associations were analyzed between DISE, BMI, and polysomnographic parameters.Complete lateral oropharyngeal collapse was significantly associated with increased severity of obstructive sleep apnea (OSA), reflected by a higher oxygen desaturation index, apnea-hypopnea index, apnea index, the percent of the total time with oxygen saturation level lower than 90%, and minimal oxygen saturation). Complete concentric collapse of the velum and complete lateral oropharyngeal collapse were associated with higher BMI values.The results of this study demonstrate a strong association between complete lateral oropharyngeal wall collapse and increased OSA severity, particularly with objective oximetry measures. Patients with a complete lateral oropharyngeal wall collapse may need aggressive treatment strategies because of the high probability of subsequent cardiovascular complications.4 Laryngoscope, 2015.

    View details for DOI 10.1002/lary.25126

    View details for PubMedID 25582498

  • Large maxillomandibular advancements for obstructive sleep apnea: An operative technique evolved over 30 years. Journal of cranio-maxillo-facial surgery Camacho, M., Liu, S. Y., Certal, V., Capasso, R., Powell, N. B., Riley, R. W. 2015; 43 (7): 1113-1118


    Obstructive sleep apnea (OSA) can be a challenging disorder to treat. Maxillomandibular advancements (MMAs) generally have high success rates; however, larger advancements have higher success and cure rates. Our aim is to present and to describe the current technique used by the senior authors, which has been successful for performing large advancements, thereby improving post-operative outcomes.The senior authors have developed and modified their maxillomandibular advancement operative techniques significantly over the past 30 years. The current version of the Riley-Powell MMA technique is described in a step-by-step fashion in this article.Initially, as part of the MMAs, patients underwent maxillomandibular fixation with wires, lag screws and harvested split calvarial bone grafts. The current technique utilizes plates, screws, Erich Arch Bars, and suspension wires which are left in place for 5-6 weeks. Guiding elastics are worn for the first week. The MMA technique described in this article has yielded a success rate over 90% for patients with a body mass index (BMI) <40 kg/m(2) and 81% for patients with a BMI ≥40 kg/m(2).Large advancements during maxillomandibular advancement surgeries can help improve post-operative obstructive sleep apnea outcomes.

    View details for DOI 10.1016/j.jcms.2015.05.015

    View details for PubMedID 26116307

  • Lateral Pharyngeal Wall Tension After Maxillomandibular Advancement for Obstructive Sleep Apnea Is a Marker for Surgical Success: Observations From Drug-Induced Sleep Endoscopy. Journal of oral and maxillofacial surgery Liu, S. Y., Huon, L., Powell, N. B., Riley, R., Cho, H. G., Torre, C., Capasso, R. 2015; 73 (8): 1575-1582


    The efficacy of maxillomandibular advancement (MMA) for obstructive sleep apnea (OSA) with anatomic airway changes has previously been studied using static imaging and endoscopy in awake subjects. The aim of the present study was to use drug-induced sleep endoscopy (DISE) to evaluate the dynamic upper airway changes in sleeping subjects before and after MMA and their association with the surgical outcome.This was a retrospective cohort study of subjects with OSA who had undergone MMA at the Stanford University Sleep Surgery Division from July 2013 to July 2014. The subjects were included if perioperative polysomnography and DISE had been performed. The predictor variable was the perioperative DISE velum-oropharynx-tongue-epiglottis score. The outcome variables were the apnea-hypopnea index (AHI), oxygen-desaturation index (ODI), and Epworth Sleepiness Scale (ESS). A subgroup analysis was performed for the subjects who had undergone primary and secondary MMA. The statistical analyses included Cronbach's α coefficient, the McNemar test, and the independent Student t test. The P value was set at <.01.A total of 16 subjects (15 males, 1 female) were included in the present study, with an average age of 47 ± 10.9 years and body mass index of 29.4 ± 5.1 kg/m(2). Significant post-MMA decreases were found in the AHI (from 59.8 ± 25.6 to 9.3 ± 7.1 events/hr) and ODI (from 45 ± 29.7 to 5.7 ± 4.1 events/hr; P < .001). Greater improvement in the AHI occurred in the primary MMA group (P = .022). The post-MMA change in airway collapse was most significant at the lateral pharyngeal wall (P = .001). The subjects with the most improvement in lateral pharyngeal wall collapsibility demonstrated the largest changes in the AHI (from 60.0 ± 25.6 events/hr to 7.5 ± 3.4 events/hr) and ODI (from 46.7 ± 29.8 to 5.3 ± 2 events/hr; P = .002).Using DISE, we observed that after MMA, the greatest reduction in upper airway collapsibility is seen at the lateral pharyngeal wall of the oropharynx, followed by the velum, and then the tongue base. The stability of the lateral pharyngeal wall is a marker of surgical success after MMA using the AHI, ODI, and ESS.

    View details for DOI 10.1016/j.joms.2015.01.028

    View details for PubMedID 25843814

  • Inferior Turbinate classification system, grades 1 to 4: Development and validation study. Laryngoscope Camacho, M., Zaghi, S., Certal, V., Abdullatif, J., Means, C., Acevedo, J., Liu, S., Brietzke, S. E., Kushida, C. A., Capasso, R. 2015; 125 (2): 296-302


    To develop a validated inferior turbinate grading scale.Development and validation study.Phase 1 development (alpha test) consisted of a proposal of 10 different inferior turbinate grading scales (>1,000 clinic patients). Phase 2 validation (beta test) utilized 10 providers grading 27 standardized endoscopic photos of inferior turbinates using two different classification systems. Phase 3 validation (pilot study) consisted of 100 live consecutive clinic patients (n = 200 inferior turbinates) who were each prospectively graded by 18 different combinations of two independent raters, and grading was repeated by each of the same two raters, two separate times for each patient.In the development phase, 25% (grades 1-4) and 33% (grades 1-4) were the most useful systems. In the validation phase, the 25% classification system was found to be the best balance between potential clinical utility and ability to grade; the photo grading demonstrated a Cohen's kappa (κ) = 0.4671 ± 0.0082 (moderate inter-rater agreement). Live-patient grading with the 25% classification system demonstrated an overall inter-rater reliability of 71.5% (95% confidence interval [CI]: 64.8-77.3), with overall substantial agreement (κ = 0.704 ± 0.028). Intrarater reliability was 91.5% (95% CI: 88.7-94.3). Distribution for the 200 inferior turbinates was as follows: 25% quartile = grade 1, 50% quartile (median) = grade 2, 75% quartile = grade 3, and 90% quartile = grade 4. Mean turbinate size was 2.22 (95% CI: 2.07-2.34; standard deviation 1.02). Categorical κ was as follows: grade 1, 0.8541 ± 0.0289; grade 2, 0.7310 ± 0.0289; grade 3, 0.6997 ± 0.0289, and grade 4, 0.7760 ± 0.0289.The 25% (grades 1-4) inferior turbinate classification system is a validated grading scale with high intrarater and inter-rater reliability. This system can facilitate future research by tracking the effect of interventions on inferior turbinates.2c Laryngoscope, 2014.

    View details for DOI 10.1002/lary.24923

    View details for PubMedID 25215619

  • Anterior Mandibular Fractures Atlas of Oral and Maxillofacial Surgery Bast, B., Liu, S. Elsevier Saunders. 2015: 680–687
  • Brain abscess potentially secondary to odontogenic infection: case report ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY ORAL RADIOLOGY Yang, J., Liu, S. Y., Hossaini-Zadeh, M., Pogrel, M. 2014; 117 (2): E108-E111


    Odontogenic infections are rarely implicated in the causes of brain abscess formation. As such, there are very few reports of brain abscesses secondary to odontogenic infections in the literature. This is due partly to the relative rarity of brain abscesses but also to the difficulty in matching the causative organisms of a brain abscess to an odontogenic source. The authors report a case of a 50-year-old woman whose brain abscess may potentially have been secondary to an odontogenic infection. The patient's early diagnosis, supported by imaging and microbiologic assessment, along with early minicraniotomy and extraction of infected dentition followed by a course of cephalosporins and metronidazole, contributed to a successful outcome.

    View details for DOI 10.1016/j.oooo.2013.08.011

    View details for Web of Science ID 000330023200009

    View details for PubMedID 24157081

  • Advancements in office-based anesthesia in oral and maxillofacial surgery. Atlas of the oral and maxillofacial surgery clinics of North America Robert, R. C., Liu, S., Patel, C., Gonzalez, M. L. 2013; 21 (2): 139-165

    View details for DOI 10.1016/j.cxom.2013.05.007

    View details for PubMedID 23981491

  • Surgical Care of the Hemifacial Microsomia Patient Current Therapy in Oral and Maxillofacial Surgery Liu, S., Good, P., Lee, J. S. Elsevier. 2012: 828–834


    Surgical resection of oral cancer can be associated with significant postoperative cardiovascular and respiratory complications that require more sensitive predictors.All patients with oral squamous cell carcinoma treated from July 2005 to April 2008 were retrospectively reviewed. The Goldman Revised Cardiac Risk Index (GRCRI) was used to predict cardiovascular complications. Other evidence-based a priori predictors were applied in an h-fold cross-validation model.Operating room (OR) time was an independent predictor of cardiovascular complications (odds ratio = 1.54, p = .002, 95% confidence interval [CI] = 1.18-2.02) and respiratory complications (odds ratio = 1.3, p = .06, 95% CI = 0.99-1.64) after multivariate adjustment. OR time and estimated blood loss predicted cardiovascular complications with 73% sensitivity. The GRCRI achieved 37% sensitivity. OR time and tracheostomy predicted respiratory complications with 75% sensitivity.The GRCRI was not prognostic for cardiovascular complications in patients with oral cancer. The most sensitive predictors for cardiovascular complications were OR time and estimated blood loss; for respiratory complications they were OR time and tracheostomy.

    View details for DOI 10.1002/hed.21411

    View details for Web of Science ID 000286290400018

    View details for PubMedID 20578073

  • Pre-operative resting arterial blood pressure modulates morbidity and mortality in oral cancer patients Liu, S. C., Lam, D. K., Schmidt, B. L. ELSEVIER SCIENCE BV. 2009: 167-168
  • Peripheral endothelin A receptor antagonism attenuates carcinoma-induced pain EUROPEAN JOURNAL OF PAIN Schmidt, B. L., Pickering, V., Liu, S., Quang, P., Dolan, J., Connelly, S. T., Jordan, R. C. 2007; 11 (4): 406-414


    In this study we investigated the role of endothelin-1 (ET-1) and its peripheral receptor (ET-A) in carcinoma-induced pain in a mouse cancer pain model. Tumors were induced in the hind paw of female mice by local injection of cells derived from a human oral squamous cell carcinoma (SCC). Significant pain, as indicated by reduction in withdrawal thresholds in response to mechanical stimulation, began at four days after SCC inoculation and lasted to 28 days, the last day of measurement. Intra-tumor expression of both ET-1 mRNA and ET-1 protein were significantly upregulated compared to normal tissue, and local administration of the ET-A receptor selective antagonist, BQ-123 (100 microM) significantly elevated withdrawal thresholds, indicating the induction of an antinociceptive effect. These findings support the suggestion that ET-1 and ET-A receptors contribute to the severity of carcinoma-induced soft tissue cancer pain.

    View details for DOI 10.1016/j.ejpain.2006.05.007

    View details for Web of Science ID 000245544600006

    View details for PubMedID 16807013

  • Increased basal ganglia volumes in velo-cardio-facial syndrome (deletion 22q11.2) BIOLOGICAL PSYCHIATRY Eliez, S., Barnea-Goraly, N., Schmitt, J. E., Liu, Y., Reiss, A. L. 2002; 52 (1): 68-70


    This study evaluated differences in caudate volumes in subjects with velo-cardio-facial syndrome due to a 22q11.2 (22qDS) deletion. Because psychosis is observed in 30% of adult subjects with 22qDS, this neurogenetic disorder could represent a putative model for a genetically mediated subtype of schizophrenia.Caudate volumes were measured on high-resolution magnetic resonance images in 30 children and adolescents with 22qDS and 30 gender- and age-matched normal comparison subjects.Caudate head volumes were increased in the 22qDS group independent of neuroleptic medications. Subjects with 22qDS also displayed an abnormal pattern of asymmetry in the anterior caudate, with left side greater than right.Alterations in the basal ganglia circuitry have been implicated in learning, cognitive, and behavioral problems in children and therefore could be involved in the expression of the neurobehavioral phenotype expressed by subjects with 22qDS. Abnormal caudate volume is a neurodevelopmental feature shared with schizophrenia, further establishing 22qDS as a potential neurodevelopmental model for this disorder.

    View details for Web of Science ID 000176340700009

    View details for PubMedID 12079732

  • Reliability of the Muller maneuver and its association with sleep-disordered breathing Meeting of the Western Section of the American-Laryngological-Rhinological-and-Otological-Society Terris, D. J., Hanasono, M. M., Liu, Y. C. JOHN WILEY & SONS INC. 2000: 1819–23


    Use of the Muller maneuver (MM) in the evaluation of patients with obstructive sleep apnea is controversial. One criticism of this test is that it is somewhat subjective. Our objective is to explore the reliability of this technique and its association with sleep-disordered breathing.Prospective study performed in an academic tertiary care center.An analysis of MM scores from 180 consecutive patients obtained independently by two examiners was completed. These scores were compared with each other and with the apnea-hypopnea index (AHI) obtained from polysomnographic studies.Collapse of the soft palate (PAL), lateral pharyngeal wall (LPW), and base of the tongue (BOT) was rated on a five-point scale (0-4). The mean scores determined by the faculty examiner were 2.47, 2.06, and 1.58, respectively; the mean scores determined by the resident examiner were 2.34, 2.25, and 1.48, respectively. The scores of the two examiners correlated to within +/- 1 unit 83.9% of the time at the PAL, 91.1% at the LPW, and 85.0% at the BOT. The degree of correlation was not influenced by year of training of the resident. When the AHI was converted to a four-point scale based on severity, the score correlated within +/- 1 of the average MM score 72.1% of the time.Despite the subjective nature of the MM, the five-point scale can be used by independent examiners to achieve an evaluation of the upper airway that is reproducible. The preoperative severity of sleep-disordered breathing based on the AHI is moderately correlated with the MM score.

    View details for Web of Science ID 000165165200009

    View details for PubMedID 11081592