Dr. Liu is as an Assistant Professor of Otolaryngology in the Division of Sleep Surgery, and is co-director of the Stanford Sleep Surgery Fellowship. He is a committee member of sleep medicine in the American Academy of Otolaryngology. He is a recent Stanford Biodesign Faculty Fellow (2018).

He received his medical and dental degrees from the University of California-San Francisco (UCSF). He was a former Howard Hughes Medical Institute (HHMI) Research Scholar (Cloister Program). After maxillofacial surgery residency at UCSF, Dr. Liu completed his sleep surgery fellowship with the Department of Otolaryngology at Stanford.

Dr. Liu practices the full scope of sleep apnea surgery including nasal, palate, tongue base, hypoglossal nerve stimulation (Inspire), genioglossus advancement, distraction osteogenesis maxillary expansion (DOME), and maxillomandibular advancement (MMA). He is also routinely referred patients for orthognathic surgery and facial trauma. In that capacity, he also serves as a preceptor to the Stanford Oculoplastic Surgery Fellowship.

His active areas of research include dynamic airway examination for sleep surgical selection, virtual surgical planning for facial skeletal surgery, and neuromodulation of the upper airway. He has published over 50 scientific articles and medical texts, with original scientific work on sleep surgery.

Clinical Focus

  • Sleep Apnea, Obstructive
  • Sleep Apnea Surgery
  • Maxillomandibular Advancement (MMA)
  • Hypoglossal Nerve Stimulation (Inspire)
  • Orthognathic Surgery
  • Facial Trauma
  • Oral and Maxillofacial Surgery

Academic Appointments

  • Assistant Professor - Med Center Line, Otolaryngology - Head & Neck Surgery Divisions

Administrative Appointments

  • Co-Director, Sleep Surgery Fellowship (2015 - Present)
  • 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 Sleep Medicine Fellowship (2014) CA
  • Residency:UCSF Otolaryngology Head and Neck Surgery Residency (2013) CA
  • Internship:UCSF General Surgery Residency (2012) CA
  • Medical Education:University of California at San Francisco School of Medicine (2011) CA
  • Dental Education:University of California at San Francisco School Of Dentistry (2007) CA
  • 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

2018-19 Courses

All Publications

  • 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

  • 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 DOI 10.1016/j.cxom.2018.11.004

    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

  • 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

  • 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

  • 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

  • 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., Huon, L. K., Yoon, A. 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

  • 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

  • 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

  • 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 DOI 10.1016/j.cxom.2018.12.001

    View details for PubMedID 30717929

  • 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

  • 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

  • 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 Web of Science ID 000428092600011

    View details for PubMedID 29554403

  • 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

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

  • 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

  • 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

  • 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

  • Ankyloglossia as a risk factor for maxillary hypoplasia and soft palate elongation: A functional - morphological study. Orthodontics & craniofacial research Yoon, A. J., Zaghi, S., Ha, S., Law, C. S., Guilleminault, C., 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., 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 DOI 10.1186/s40902-017-0126-0

    View details for PubMedID 29018786

    View details for PubMedCentralID PMC5610953

  • 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

  • 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): 1533–38


    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

  • 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., Gouveia, C. J., Mack, D., Vivian, C., Abdullatif, J., Mangili, S., Liu, S. Y., Zaghi, S., Camacho, M. 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

  • 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

  • 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

  • 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

  • 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 Web of Science ID 000385202600071

    View details for PubMedID 27276991

  • 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., Tolisano, A. M., Chang, E. T., Liu, S. Y., Certal, V., Camacho, M. 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

  • 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
  • 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

  • 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 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