Tim Tirrell

All Publications

• Patch Repair Versus Flap Repair for Congenital Diaphragmatic Hernia: A Systematic Review and Meta-Analysis. Journal of pediatric surgery Fatimi, A. S., Salman, R., Manal, H., Anns, K. M., Thobani, H., Ehsan, A. N., Rao, A. G., Tahan, D., Tirrell, T. F., Islam, S., Khan, F. A. 2026: 162919

  Abstract

  Congenital diaphragmatic hernia (CDH) often requires non-primary repair of large defects using either a prosthetic patch or an autologous muscle flap. However, their comparative effectiveness remains uncertain. We systematically reviewed the existing literature to synthesize outcomes relevant to durability and perioperative safety of patch versus flap repair in neonates.PubMed, Embase, and Scopus were systematically searched from inception to May 2025 for pediatric studies directly comparing patch versus flap repair for CDH in neonates. Meta-analyses were performed using random-effects models on RevMan v5.4.1. Risk of bias was assessed using the ROBINS-I tool.Ten single-center retrospective cohorts comprising a total of 450 patients (Patch Repair: 220, Flap Repair: 230) who underwent CDH repair were included in our synthesis. Patch repair was associated with an increased risk of hernia recurrence (RR: 3.57 [95% CI: 1.47-8.69]), postoperative bleeding complications (RR: 2.15 [95% CI: 1.09-4.24]), and in-hospital mortality (RR: 1.66 [95% CI: 1.13-2.43]). No statistically significant differences were detected in the rates of chest wall deformities, scoliosis, bowel obstruction, ventral incisional hernia, operative time, or hospital length of stay. However, the overall certainty of evidence was very low across most outcomes, reflecting the retrospective designs, small sample sizes, and inconsistent follow-up/definitions.Within low-certainty evidence, patch repair was associated with higher observed hernia recurrence. Data on postoperative bleeding and mortality, including among on-ECMO repairs, were limited and insufficient to support causal inference. Definitive guidance will require prospective multicenter studies using standardized techniques, adjudicated bleeding endpoints, and long-term surveillance.

  View details for DOI 10.1016/j.jpedsurg.2026.162919

  View details for PubMedID 41539378

• Assessing the Value of Overnight Admission After Pediatric Laparoscopic Cholecystectomy: A Nationwide Propensity-Matched Analysis. Journal of pediatric surgery Javid, A., Minhas, A., Thobani, H., McRae, J., Mladenov, G., Ehsan, A. N., Gundershausen, M., Tahan, D., Tagge, E. P., Tirrell, T., Radulescu, A., Khan, F. A. 2025: 162870

  Abstract

  In an era of constrained healthcare resources, optimizing postoperative care without compromising safety has become a national priority. Laparoscopic cholecystectomy (LC) is among the most common pediatric procedures, yet discharge practices vary widely. Whether overnight admission offers meaningful benefit over same-day discharge remains uncertain.Children (<18 years) undergoing LC from 2017-2023 were identified in the American College of Surgeons National Surgical Quality Improvement Program-Pediatric (NSQIP-P) participant use file. Patients were classified by discharge timing (same-day vs overnight). Propensity score matching (1:1) balanced demographic, clinical, and operative factors. The primary outcome was 30-day unplanned readmission; secondary outcomes included reintervention and postoperative complications.Among 15,809 patients, 11,969 (76%) were discharged the same day. After matching (n = 1,725/group), same-day discharge was associated with lower odds of unplanned readmission (aOR 0.56, 95% CI 0.38-0.80) and reintervention (aOR 0.16, 95% CI 0.05-0.41). Absolute event rates were lower for readmissions (2.7% vs 4.7%, p=0.002) and reinterventions (0.2% vs 1.4%, p<0.001) in the same-day group. Notably, 96% of readmissions occurred after 24 hours and were for transient postoperative concerns unlikely to be prevented by inpatient observation. In an exploratory analysis of 2023 cases, opioid prescription at discharge was independently associated with increased readmission risk (aOR 1.97, 95% CI 1.00-3.78).Same-day discharge after pediatric LC is common, safe, and resource-efficient. Overnight admission adds minimal safety benefit while consuming limited inpatient capacity. These findings support broader adoption of standardized same-day discharge pathways to promote responsible resource stewardship in pediatric surgical care.Retrospective Cohort Study LEVEL OF EVIDENCE: III.

  View details for DOI 10.1016/j.jpedsurg.2025.162870

  View details for PubMedID 41397633

• Outcomes of Sutureless versus Sutured Closure for Gastroschisis: A Systematic Review and Meta-Analysis. Journal of pediatric surgery Rao, A. G., Awan, A. R., Ayazuddin, M., Thobani, H., Ehsan, A. N., Fatimi, A. S., Minhas, A., Javid, A., Tirrell, T. F., Sylvester, K. G., Islam, S., Khan, F. A. 2025: 162867

  Abstract

  Sutureless closure is a minimally invasive alternative to traditional sutured repair for gastroschisis, yet, uncertainty persists regarding its safety and outcomes. This systematic review and meta-analysis aimed to compare treatment outcomes of sutured and sutureless gastroschisis closure.We searched the PubMed, Embase, Scopus, and ClinicalTrials.gov repositories for studies comparing outcomes of sutureless versus sutured gastroschisis closure from inception to June 2025. Outcome included mortality, feeding milestones, anesthesia outcomes, hernia outcomes, hospital stay, and postoperative complications. A random-effects model was applied and meta-regression was also conducted.Twenty-three studies (2,646 infants; 821 sutureless, 1,825 sutured) were included. Sutureless repair did not increase mortality risk [Risk ratio (RR)=1.11; 95% CI=0.61, 2.03), or delay feeding milestones [time to full feeds mean difference (MD)=-1.62 days; 95%=CI: -4.61, 1.38], although regional analyses favored faster feeding with sutureless repair (p < 0.01). Sutureless closure was associated with significantly reduced utilization of general anesthesia (RR=0.23; 95% CI=0.15, 0.36; p < 0.00001), shortened ventilation duration (MD=-1.96 days; 95% CI=-2.66, -1.26; p < 0.01), and reduced surgical site infection risk (RR=0.60; 95% CI=0.43, 0.83; p = 0.003). However, umbilical hernia incidence (RR=2.50; 95% CI=1.57, 3.98) and hernia repair (RR=2.66; 95% CI=1.65, 4.27) were higher following sutureless closure. Hospital stay showed no overall difference, and sutureless repair did not increase the risk for postoperative complications. Meta-regression identified regional practices, sex distribution, and case mix as key modifiers, highlighting the influence of center-level practices and the observational nature of the data.Sutureless closure offers substantial perioperative advantages but carries a higher umbilical hernia risk. However, these findings arise predominantly from observational studies and may be influenced by confounding by indication and institutional practice patterns. While the overall evidence supports sutureless closure as a safe approach, structured follow-up and family counseling are warranted.

  View details for DOI 10.1016/j.jpedsurg.2025.162867

  View details for PubMedID 41391653

• Outcomes of Pouch Creation in 2-Stage Versus 3-Stage Procedures for Pediatric Ulcerative Colitis: A Propensity Score Matched Comparative Analysis. Inflammatory bowel diseases Thobani, H., Ehsan, A. N., Moturu, A., Nepomuceno, H. M., Taufiq, M., Zahid, N., Tirrell, T. F., Sylvester, K. G., Islam, S., Khan, F. A. 2025

  Abstract

  Staged proctocolectomy with ileal pouch-anal anastomosis (IPAA) is the standard surgical treatment for medically refractory pediatric ulcerative colitis (UC). This study aimed to compare the surgical outcomes of 2-stage and 3-stage IPAA in children of similar disease severity.We queried the NSQIP-Pediatric database (2016-2023) to identify patients under 18 years with UC undergoing IPAA. Patients undergoing IPAA with concurrent colectomy were classified as having a 2-stage procedure, while those undergoing IPAA alone, following a prior colectomy, were classified as having a 3-stage procedure. The primary outcome was a composite of major complications within 30 days, including mortality, organ/space infection, progressive renal insufficiency, systemic sepsis, and intra-abdominal reoperation. The treatment groups were matched using 1:1 propensity score matching to adjust for baseline differences in disease severity.A total of 479 patients met the inclusion criteria (330 underwent 3-stage and 149 underwent 2-stage procedures). The proportion of patients undergoing each approach remained stable over the study period (P = .693). At the time of pouch creation, the 2-stage group had significantly higher rates of steroid use (22.8% vs 14.5%), leukocytosis (21.9% vs 7.1%), and hypoalbuminemia (mean 4.0 vs 4.2 g/dL). After matching, 137 patient pairs were included. There was no significant difference in major complication rates between groups (OR, 1.38; 95% CI, 0.63-3.09).This study demonstrated that surgical outcomes following pouch creation were similar in a matched cohort of children undergoing 2- or 3-stage IPAA, supporting the use of a 2-stage approach in certain patients with limited disease.

  View details for DOI 10.1093/ibd/izaf241

  View details for PubMedID 41128337

• Antibiotic Prophylaxis for Gastrointestinal Surgery Among Neonates and Very Young Infants: National Patterns, Outcomes, and Opportunities for Precision Stewardship. The Journal of pediatrics Thobani, H., Mathew, R., Ehsan, A. N., Moturu, A., Khan, M. O., Bio, L., Sankar, M., Tirrell, T. F., Shah, A. A., Thorson, C. M., Raymond, S. L., Islam, S., Sylvester, K. G., Khan, F. A. 2025: 114839

  Abstract

  To evaluate nationwide adherence to surgical antibiotic prophylaxis (SAP) guidelines and the association with outcomes following gastrointestinal surgeries among neonates and infants.We queried the National Surgical Quality Improvement Program-Pediatric for all patients age <90 days undergoing gastrointestinal surgery between 2021-2023. Procedures were further subcategorized by anatomic site. SAP regimens were classified as being "adherent," "undercoverage," or "overcoverage" per established guidelines and expert consensus. The primary outcome was surgical site infection (SSI). Associations between SAP classification and SSI rates for each procedure subcategory were analyzed, with further subset analyses to delineate the effects of common SAP regimens on postoperative outcomes.A total of 11,062 cases met criteria, with an overall SAP adherence of 87.2%. Rates of overcoverage (2.8%-55.5%) and undercoverage (2.8%-28.3%) varied widely by procedure type. SAP undercoverage did not increase the odds of SSI for most procedures analyzed, with the exception of patients undergoing colorectal procedures, in whom cefazolin monotherapy (undercoverage) was associated with higher odds of SSI (OR=2.17, 95% CI=1.08-4.18). Broadening SAP coverage (overcoverage) and prolonging SAP duration were not associated with reduced SSI rates for any subcategory of procedure.Adherence to empiric SAP guidelines has been applied poorly to neonates and very young infants undergoing gastrointestinal surgery. There appears to be limited benefit to broadening SAP coverage for surgery in this patient population. These findings underscore the need for increased adherence to recommendations driven by neonatal-specific data , aiming to balance optimized post-operative outcomes with antimicrobial stewardship goals.

  View details for DOI 10.1016/j.jpeds.2025.114839

  View details for PubMedID 41016460

• Outcomes of a Second Run of Extracorporeal Membrane Oxygenation in Neonates: A Propensity Score Matched Analysis of a Nationwide Registry. ASAIO journal (American Society for Artificial Internal Organs : 1992) Thobani, H., Khan, M. O., Tirrell, T. F., Khan, F. A., Islam, S. 2025

  Abstract

  This study analyzed the outcomes of neonates undergoing a second run of extracorporeal membrane oxygenation (ECMO) to determine whether there is a benefit to a repeated run. We used Extracorporeal Life Support Organization data to compare neonates undergoing a single versus two runs of ECMO from 2009 to 2019. Baseline characteristics of single-run patients were compared with the first run in two-run patients to identify clinical predictors of a second run of ECMO. Furthermore, we compared overall survival outcomes and ECMO-related complications in single-run and two-run patients, with propensity score matching to adjust for baseline differences between the groups. A total of 12,292 patients undergoing 12,668 ECMO runs met criteria. Neonates requiring a second run had a shorter duration of the first ECMO run (p < 0.001) and were more likely to have had venoarterial cannulation (p < 0.001) than single-run patients. Overall, 33.8% of patients undergoing a second run survived until discharge, compared with 62.9% of patients undergoing a single run only. Propensity score matched analysis demonstrated that patients undergoing two runs were more likely to die, irrespective of underlying physiologic status or ECMO indication (odds ratio [OR] = 3.53, 95% confidence interval [CI] = 2.75-4.56). Nevertheless, nearly a third of patients undergoing two ECMO runs survived until discharge, indicating that recannulation may be beneficial in certain patient cohorts.

  View details for DOI 10.1097/MAT.0000000000002546

  View details for PubMedID 40923597

• Antibiotic Stewardship in Pediatric Complicated Appendicitis: Assessing the Role of Oral Antibiotics after Discharge. Journal of pediatric surgery Thobani, H., Nepomuceno, H. M., Schwab, M. E., Emengo, P. O., Khan, R., Raymond, S. L., Shah, A. A., Mathew, R., Tirrell, T. F., Islam, S., Sylvester, K. G., Khan, F. A. 2025: 162594

  Abstract

  To determine whether home oral antibiotic (OA) use after appendectomy for pediatric complicated appendicitis reduces post-discharge complications in children who are afebrile prior to discharge.We queried the National Surgical Quality Improvement Program-Pediatric (NSQIP-P) dataset for children aged 1-18 years who underwent appendectomy for complicated appendicitis between 2019-2023. Patients were included if they were afebrile and had no infective complications (i.e. fever, surgical site infections etc.) at discharge. All patients were stratified into age groups (ages 1-5, 5-10 and 10-18) and were subsequently grouped by whether they were prescribed home OA. The primary outcome measure was post-discharge intra-abdominal abscess (IAA). The relationship between home OA use and post-discharge outcomes was analyzed using multivariable logistic regression.A total of 20,190 patients met criteria, with a median age of 10.0 years (IQR: 6.9-13.1). Approximately 70.9% of patients received home OA and 29.1% did not. Patient characteristics including age, preoperative WBC count, operative time, and length of stay appeared similar at baseline on unadjusted analysis. On multivariable analysis, home OA use did not reduce the odds of IAA in any age group (Age 1-5: aOR=1.27, 95% CI=0.80-2.09; Age 5-10: aOR=1.15, 95% CI=0.90-1.50; Age 10-18: aOR=1.05, 95% CI=0.86-1.30). A subset analysis conducted for patients aged 5-18 years with intraoperative findings of perforated appendicitis also failed to identify any association between home OA use and post-discharge IAA (aOR=1.09, 95% C.I.=0.92-1.29).There appears to be limited benefit to prescribing home OA for children with complicated appendicitis who are afebrile after appendectomy.Retrospective Cohort Study LEVEL OF EVIDENCE: Level III evidence.

  View details for DOI 10.1016/j.jpedsurg.2025.162594

  View details for PubMedID 40845978

• Water Soluble Contrast Administration in the Management of Pediatric Adhesive Small Bowel Obstruction: A Systematic Review and Meta-Analysis. Journal of pediatric surgery Thobani, H., Khan, M. O., Minhas, A., Fatimi, A. S., Khan, R., Tirrell, T. F., Sylvester, K. G., Islam, S., Khan, F. A. 2025: 162465

  Abstract

  Water soluble contrast administration (WSCA) is increasingly being adopted as part of non-operative management (NOM) for adhesive small bowel obstruction (ASBO) in children. We undertook a systematic review and meta-analysis to characterize reported WSCA-based NOM protocols and evaluate their diagnostic and therapeutic efficacy in pediatric ASBO.A systematic review of four research repositories was conducted in accordance with the PRISMA standards. Two reviewers screened relevant articles for inclusion, with disputes mediated by a third reviewer. Appraisal of risk of bias and certainty of evidence was conducted using the Cochrane ROBINS-I tool and the GRADE approach respectively.Of the110 unique studies screened, 7 studies reporting 402 cases of pediatric ASBO met criteria. WSCA protocols varied between included studies. Three studies reported test characteristics of WSCA as a means to evaluate risk of progression to surgical intervention, with a pooled sensitivity and specificity of 98.9% and 83.1% respectively. Regarding therapeutic benefit, three studies compared progression to surgical intervention between children receiving WSCA-based NOM versus those receiving standard NOM. There was no difference in progression to surgical intervention between the two groups on pooled analysis (pooled OR=0.66, 95% CI=0.11-3.96, I2=38%). There were no major WSCA-related complications, including aspiration, anaphylaxis or renal failure, reported in any studies.There is limited evidence to suggest that WSCA-based NOM is associated with reduced progression to surgical intervention. However, given the low risk of complications or adverse events, WSCA may have a role in standardizing care pathways for children with ASBO.Systematic review and meta-analysis LEVEL OF EVIDENCE: Level II evidence (systematic review of non-randomized studies).

  View details for DOI 10.1016/j.jpedsurg.2025.162465

  View details for PubMedID 40675443

• Early Versus Late Inguinal Hernia Repair in Preterm Neonates: An Updated Systematic Review and Meta-Analysis with Trial Sequential Analysis. Journal of pediatric surgery Khan, M. O., Fatimi, A. S., Thobani, H., Ehsan, A. N., Saqib, S., Tahan, D., Tirrell, T. F., Sylvester, K. G., Islam, S., Khan, F. A. 2025: 162463

  Abstract

  The optimal timing of inguinal hernia repair in preterm neonates remains debated. Early repair may reduce incarceration risk but increases perioperative complications, while delayed repair lowers anesthetic risk but raises the risk of incarceration while awaiting repair. In the absence of consensus guidelines, practices vary widely. This systematic review and meta-analysis aimed to compare early (during birth hospitalization) versus delayed (post-discharge) inguinal hernia repair in preterm neonates.PubMed, Embase, Scopus, Web of Science, and CENTRAL were systematically searched from inception to May 2025. All original studies reporting data on early and delayed repair of inguinal hernia in preterm neonates were included. Meta-analyses were performed using random-effects models on RevMan version 5.4.1.Eleven studies involving 5,021 preterm infants were included, comprising one RCT and ten retrospective cohort studies. Early repair was associated with statistically significantly increased risks of hernia recurrence (RR: 2.52 [95% CI: 1.16, 5.48], apnea requiring intervention (RR: 3.08 [95% CI: 1.71, 5.55]), prolonged intubation (>48 hours; RR: 4.97 [95% CI: 2.40, 10.27]), metachronous hernia (RR: 6.32 [95% CI: 2.44, 16.42]), and prolonged hospital stay (MD: 10.40 days [95% CI: 1.63, 19.17]). No statistically significant differences were found in the risk of testicular atrophy, injury to adjacent structures, or operative time.Delayed hernia repair in preterm neonates may be associated with lower risks of recurrence and respiratory complications without a significant increase in risk of incarceration while awaiting repair. Further high-quality prospective studies are needed to optimize timing guidelines.

  View details for DOI 10.1016/j.jpedsurg.2025.162463

  View details for PubMedID 40659304

• Technical Considerations in Primary Repair of a Congenital Prostatic Rectourethral Fistula in an Adult-Sized Patient. European journal of pediatric surgery reports Tirrell, T. F., Demehri, F. R., Nandivada, P., McNamara, E. R., Dickie, B. H. 2022; 10 (1): e20-e24

  Abstract

  Congenital anorectal malformations are generally diagnosed and repaired as a neonate or infant, but repair is sometimes delayed. Considerations for operative repair change as the patient approaches full stature. We recently encountered a 17-year-old male with an unrepaired congenital rectourethral fistula and detail our experience with his repair. We elected to utilize a combined abdominal and perineal approach, with robotic assistance for division of his rectourethral fistula and pullthrough anoplasty. Cystoscopy was used simultaneously to assure full dissection of the fistula and to minimize the risk of leaving a remnant of the original fistula (also known as a posterior urethral diverticulum). The procedure was well tolerated without complications. His anoplasty was evaluated 60 days postoperatively and was well healed without stricture. At 9 months of follow-up, he has good fecal and urinary continence. Robotic assistance in this procedure allowed minimal perineal dissection while ensuring precise rectourethral fistula dissection. The length of the intramural segment of the fistula was longer than anticipated. Simultaneous cystoscopy, in conjunction with the integrated robotic fluorescence system, helped reduce the risk of leaving a remnant of the original fistula.

  View details for DOI 10.1055/s-0041-1742155

  View details for PubMedID 35169532

  View details for PubMedCentralID PMC8840860

• Hindgut Duplication in an Infant with Omphalocele-Exstrophy-Imperforate Anus-Spinal Defects (OEIS) Complex. European journal of pediatric surgery reports Tirrell, T. F., Demehri, F. R., Lillehei, C. W., Borer, J. G., Warf, B. C., Dickie, B. H. 2022; 10 (1): e45-e48

  Abstract

  Introduction  The congenital anomaly of omphalocele, cloacal exstrophy, imperforate anus, and spinal abnormalities (OEIS complex) is rare but well recognized. Hindgut duplications are also uncommon and are not known to be associated with OEIS. We describe a neonate with OEIS who was found to have fully duplicated blind-ending hindguts. Case Report  A premature infant boy with OEIS underwent first-stage closure on day of life 6, which included excision of the omphalocele sac, separation of the cecal plate and bladder halves, tubularization of the cecal plate, hindgut rescue with end colostomy, and joining of the bladder halves. Cecal plate inspection revealed two hindgut structures that descended distally, one descended midline into the pelvis along the sacrum and the second laterally along the left border of the sacrum. Both lumens connected to the cecal plate and had separate mesenteries. In an effort to maximize the colonic mucosal surface area, the hindgut segments were unified through a side-to-side anastomosis, creating a larger caliber hindgut. The cecal plate was tubularized and an end colostomy was created. Bowel function returned and he was discharged home on full enteral feeds. Discussion  This case represents a cooccurrence of two extremely rare and complex congenital anomalies. The decision to unify the distinct hindguts into a single lumen was made in an effort to combine the goals of management for both OEIS and alimentary duplications. The hindgut is abnormal in OEIS and should be assessed carefully during repair.

  View details for DOI 10.1055/s-0041-1742154

  View details for PubMedID 35282303

  View details for PubMedCentralID PMC8913173

• Contrast enhanced colostography: New applications in preoperative evaluation of anorectal malformations JOURNAL OF PEDIATRIC SURGERY Tirrell, T. F., Demehri, F. R., McNamara, E. R., Paltiel, H. J., Barnewolt, C. E., Padua, H. M., Chow, J. S., Dickie, B. H. 2021; 56 (1): 192-195

  Abstract

  Understanding details of anatomic relationships between the colon and surrounding structures is a critical piece of preoperative planning prior to surgical repair of anorectal malformations (ARMs). Traditional imaging techniques involve ionizing radiation, distention of the rectum with supraphysiologic intraluminal pressures, and sometimes require sedation. Recent developments in the field of contrast agents have allowed the emergence of an ultrasound-based technique that can avoid these requirements while continuing to provide high resolution structural information in three dimensions.Fourteen children (13 male, 1 female, age 1-11 months) with ARMs underwent contrast enhanced colostography (ceCS) in addition to traditional preoperative imaging techniques to delineate anatomic relationships of pelvic structures.ceCS and traditional imaging yielded concordant anatomic information, including structural relationships and fistulous connections, in 10/14 patients (71%). ceCS detected fistulous connection in 2/13 patients (15%) that were not seen by traditional imaging. Ultrasonography failed to detect the fistulous connection in one patient.ceCS is a safe, effective and flexible method for defining important structural information in ARM patients. When compared with traditional methods, it provided equivalent or superior results 93% of the time and bears consideration as a standard tool in preoperative planning for this population.Retrospective Comparative Study.Level III.

  View details for DOI 10.1016/j.jpedsurg.2020.09.033

  View details for Web of Science ID 000608686400032

  View details for PubMedID 33143879

• Safety of delayed surgical repair of omphalocele-exstrophy-imperforate anus-spinal defects (OEIS) complex in infants with significant comorbidities PEDIATRIC SURGERY INTERNATIONAL Tirrell, T. F., Demehri, F. R., Henry, O. S., Cullen, L., Lillehei, C. W., Warf, B. C., Gates, R. L., Borer, J. G., Dickie, B. H. 2021; 37 (1): 93-99

  Abstract

  Management of infants with OEIS complex is challenging and not standardized. Expeditious surgery after birth has been recommended to limit soilage of the urinary tract and optimize intestinal function. However, clinical instability secondary to comorbidities is common in this population and early operation carries risk. We sought to define the risk/benefit profile of delaying repair.All newborn patients with OEIS managed by our institution between Sep 2017 and Oct 2019 were reviewed. Comorbidities were evaluated, including cardiopulmonary pathologies and associated malformations.Ten patients with OEIS were managed. Patients underwent early (2 patients, repair at 0-2 days) or delayed (6 patients, repair at 6-87 days) first-stage exstrophy repair. Two patients died prior to repair (progressive respiratory failure, severe genetic anomalies). Repairs were delayed secondary to cardiac conditions, neurosurgical interventions, medical disease, and/or delayed transfer. Delayed repair patients had longer lengths of stay and use of parenteral nutrition. No patients experienced urinary tract infections prior to repair.Delaying first-stage exstrophy repair to allow physiologic optimization is safe. All repaired patients were discharged home, without parenteral nutrition or supplemental oxygen.

  View details for DOI 10.1007/s00383-020-04779-w

  View details for Web of Science ID 000592162800001

  View details for PubMedID 33231719

  View details for PubMedCentralID 1357748

• A New Approach to Cloaca: Laparoscopic Separation of the Urogenital Sinus JOURNAL OF LAPAROENDOSCOPIC & ADVANCED SURGICAL TECHNIQUES Demehri, F. R., Tirrell, T. F., Shaul, D. B., Sydorak, R. M., Zhong, W., McNamara, E. R., Borer, J. G., Dickie, B. H. 2020; 30 (12): 1257-1262

  Abstract

  Introduction: Cloaca malformation repair strategy is strongly dictated by common channel and urethral lengths. Mid to long common channel cloacas are challenging and often require laparotomy for dissection of pelvic structures. The balance of common channel and urethral lengths often dictates the approach for reconstruction. Laparoscopy has been utilized for rectal dissection but not for management of the urogenital (UG) structures. We hypothesized that laparoscopy could be applied to UG separation in reconstruction of cloaca malformations. Methods: Records were reviewed for 9 children with cloaca who underwent laparoscopic rectal mobilization and UG separation. Clinical parameters reviewed included demographics, relevant anatomic lengths, operative duration, transfusion requirements, and perioperative complications. Results: Repair was perfomed at a median (interquartile range) age of 12 (7, 15) months. Common channel length as measured by cystoscopy was 3.5 (3.3, 4.5) cm. There were no intraoperative complications. Transfusion requirements were minimal. Postoperative length of stay was 6 (5, 11) days. One patient developed a urethral web and 2 developed vaginal stenosis. One patient later underwent a laparotomy for obstruction due to a twisted rectal pull-through. Conclusions: Laparoscopic rectal mobilization and UG separation in long common channel cloaca are safe and well tolerated. Laparoscopy affords full evaluation of Mullerian structures and enables separation of the common UG wall, which may ultimately enhance long-term urinary continence.

  View details for DOI 10.1089/lap.2020.0641

  View details for Web of Science ID 000592656500001

  View details for PubMedID 33202165

• Reoperative surgery in anorectal malformation patients TRANSLATIONAL GASTROENTEROLOGY AND HEPATOLOGY Tirrell, T. F., McNamara, E. R., Dickie, B. H. 2021; 6: 43

  Abstract

  Currently accepted primary repair of congenital anorectal malformations (ARMs) includes a posterior sagittal incision, which allows for optimal visualization and identification of important pelvic structures and anatomical features. Reconstructive surgery involves meticulous dissection and separation of pelvic structures, and careful reconstruction can result in good functional outcomes for many patients, who live without ongoing sequelae from their malformation. However, some patients may require reoperative procedures for anatomic or functional reasons. Males and females present with slightly different symptoms and should be approached differently. Males are most likely to require reoperations for anorectal or urethral pathologies, but the urinary system is often spared in females-they instead must contend with Mullerian duct anomalies, of which there are many varieties. Depending on the original malformation and severity of symptoms, redo surgery may be needed to optimize function and quality of life. Surgical management with reoperative surgery in ARMs ranges from straightforward to complex, depending on the issue. One must weigh the risks of reoperative surgery and potentially creating more scarring against the need for a better anatomical and functional outcome. Current management trends and practice patterns with regards to reoperative surgery in ARM patients are not widely studied or standardized but we provide an overview of the more common pathologies, preoperative evaluation and workup required to identify the issues, and options for reoperative repair in these patients.

  View details for DOI 10.21037/tgh-20-214

  View details for Web of Science ID 000675467800001

  View details for PubMedID 34423164

  View details for PubMedCentralID PMC8343547

• Measure twice and cut once: Comparing endoscopy and 3D cloacagram for the common channel and urethral measurements in patients with cloacal malformations JOURNAL OF PEDIATRIC SURGERY Halleran, D. R., Smith, C. A., Fuller, M. K., Durhm, M. M., Dickie, B., Avansino, J. R., Tirrell, T. F., Vandewalle, R., Reeder, R., Drake, K. R., Bates, D., Rollins, M. D., Levitt, M. A., Wood, R. J., Pediat Colorectal Pelvic Learning 2020; 55 (2): 257-260

  Abstract

  Precise and accurate measurement of the common channel and urethra is a critical determinant prior to the repair of cloacal malformations. Endoscopy and 3D reconstruction cloacagram are two common modalities utilized to help plan the surgical approach, however the consistency between these methods is unknown.Common channel and urethral lengths obtained by endoscopy and 3D cloacagram of cloaca patients at six pediatric colorectal centers were compared. Data are given as mean (range).72 patients were included in the study. Common channel measurements determined by 3D cloacagram and endoscopy were equal in 7 cases (10%). Endoscopic measurements of the common channel were longer than 3D cloacagram in 20 (28%) cases and shorter in the remaining 44 (62%) cases. The absolute difference between measurements of the common channel was 7.2 mm (0-2.4 cm). Urethral measurements by both modalities were equal in 8 cases (12%). Endoscopic measurement of the urethra was longer than that by 3D cloacagram in 20 (31%) patients and shorter in 37 (57%) of cases. The absolute difference between measurements of the urethra was 5.1 mm (0-2.0 cm). The reconstruction (e.g. TUM or urogenital separation) that would be performed according to measurements determined by 3D cloacagram and endoscopic measurements differed in 13/62 (21%) patients with each structure identified and common channel measurements of >1 cm.Significant variation exists in the measurements of the common channel and urethra in patients with cloacal malformations as determined by endoscopy and 3D cloacagram. This variation should be considered as these measurements influence the decision to perform either a TUM or urogenital separation. Based on these findings, 3D cloacagram should be performed in all patients prior to cloaca repair to prevent mischaracterization of the malformation.Level IV.

  View details for DOI 10.1016/j.jpedsurg.2019.10.045

  View details for Web of Science ID 000510865200011

  View details for PubMedID 31784103

• Analysis of hierarchical biomechanical data structures using mixed-effects models JOURNAL OF BIOMECHANICS Tirrell, T. F., Rademaker, A. W., Lieber, R. L. 2018; 69: 34-39

  Abstract

  Rigorous statistical analysis of biomechanical data is required to understand tissue properties. In biomechanics, samples are often obtained from multiple biopsies in the same individual, multiple samples tested per biopsy, and multiple tests performed per sample. The easiest way to analyze this hierarchical design is to simply calculate the grand mean of all samples tested. However, this may lead to incorrect inferences. In this report, three different analytical approaches are described with respect to the analysis of hierarchical data obtained from muscle biopsies. Each method was used to analyze an actual experimental data set obtained from muscle biopsies of three different muscles in the human forearm. The results illustrate the conditions under which mixed-models or simple models are acceptable for analysis of these types of data.

  View details for DOI 10.1016/j.jbiomech.2018.01.013

  View details for Web of Science ID 000426229300005

  View details for PubMedID 29366561

  View details for PubMedCentralID PMC5913736

• Lymph node assessment and survival: we still have work to do JOURNAL OF THORACIC DISEASE Tirrell, T., Onaitis, M. 2018; 10 (1): 15-16

  View details for DOI 10.21037/jtd.2017.12.112

  View details for Web of Science ID 000425262600029

  View details for PubMedID 29600011

  View details for PubMedCentralID PMC5863158

• The mechanical strength of side-to-side tendon repair with mismatched tendon size and shape JOURNAL OF HAND SURGERY-EUROPEAN VOLUME Friden, J., Tirrell, T. F., Bhola, S., Lieber, R. L. 2015; 40 (3): 239-245

  Abstract

  Tendon transfers frequently require coaptation of two mismatched tendons. In this cadaver study, ultimate load, stiffness, and Young's modulus were measured in tendon-to-tendon attachments with mismatched donor and recipient tendons, using pronator teres (PT) to extensor carpi radialis brevis (ECRB) and flexor carpi ulnaris (FCU) to extensor digitorum communis (EDC). FCU-to-EDC attachments failed at higher loads than PT-to-ECRB attachments, but they had similar modulus and stiffness values. Ultimate tensile strength of the tendon attachments exceeded the maximum predicted contraction force of any of the transferred muscles, with safety factors of four-fold for the FCU-to-EDC and two-fold for the PT-to-ECRB transfers. This implies that size and shape mismatches should not be contraindications to tendon attachment in transfers. The strength safety factors suggest that postoperative immobilization of these transfers is unnecessary.

  View details for DOI 10.1177/1753193413517327

  View details for Web of Science ID 000350118500003

  View details for PubMedID 24413573

  View details for PubMedCentralID PMC4366193

• Functional Consequence of Distal Brachioradialis Tendon Release: A Biomechanical Study JOURNAL OF HAND SURGERY-AMERICAN VOLUME Tirrell, T. F., Franko, O. I., Bhola, S., Hentzen, E. R., Abrams, R. A., Lieber, R. L. 2013; 38A (5): 920-926

  Abstract

  Open reduction and internal fixation of distal radius fractures often necessitates release of the brachioradialis from the radial styloid. However, this common procedure has the potential to decrease elbow flexion strength. To determine the potential morbidity associated with brachioradialis release, we measured the change in elbow torque as a function of incremental release of the brachioradialis insertion footprint.In 5 upper extremity cadaveric specimens, we systematically released the brachioradialis tendon from the radius and measured the resultant effect on brachioradialis elbow flexion torque. We defined release distance as the distance between the release point and the tip of the radial styloid.Brachioradialis elbow flexion torque dropped to 95%, 90%, and 86% of its original value at release distances of 27, 46, and 52 mm, respectively. Importantly, brachioradialis torque remained above 80% of its original value at release distances up to 7 cm.Our data demonstrate that release of the brachioradialis tendon from its insertion has minor effects on its ability to transmit force to the distal radius.These data imply that release of the distal brachioradialis tendon during distal radius open reduction internal fixation can be performed without meaningful functional consequences to elbow flexion torque. Even at large release distances, overall elbow flexion torque loss after brachioradialis release would be expected to be less than 5% because of the much larger contributions of the biceps and brachialis. Use of the brachioradialis as a tendon transfer donor should not be limited by concerns of elbow flexion loss, and the tendon could be considered as an autograft donor.

  View details for DOI 10.1016/j.jhsa.2013.01.029

  View details for Web of Science ID 000318581100012

  View details for PubMedID 23528425

  View details for PubMedCentralID PMC3640432

• Mobile Tablet Use among Academic Physicians and Trainees JOURNAL OF MEDICAL SYSTEMS Sclafani, J., Tirrell, T. F., Franko, O. I. 2013; 37 (1): 9903

  Abstract

  The rapid adoption rate and integration of mobile technology (tablet computing devices and smartphones) by physicians is reshaping the current clinical landscape. These devices have sparked an evolution in a variety of arenas, including educational media dissemination, remote patient data access and point of care applications. Quantifying usage patterns of clinical applications of mobile technology is of interest to understand how these technologies are shaping current clinical care. A digital survey examining mobile tablet and associated application usage was administered via email to all ACGME training programs. Data regarding respondent specialty, level of training, and habits of tablet usage were collected and analyzed. 40% of respondents used a tablet, of which the iPad was the most popular. Nearly half of the tablet owners reported using the tablet in clinical settings; the most commonly used application types were point of care and electronic medical record access. Increased level of training was associated with decreased support for mobile computing improving physician capabilities and patient interactions. There was strong and consistent desire for institutional support of mobile computing and integration of mobile computing technology into medical education. While many physicians are currently purchasing mobile devices, often without institutional support, successful integration of these devices into the clinical setting is still developing. Potential reasons behind the low adoption rate may include interference of technology in doctor-patient interactions or the lack of appropriate applications available for download. However, the results convincingly demonstrate that physicians recognize a potential utility in mobile computing, indicated by their desire for institutional support and integration of mobile technology into medical education. It is likely that the use of tablet computers in clinical practice will expand in the future. Thus, we believe medical institutions, providers, educators, and developers should collaborate in ways that enhance the efficacy, reliability, and safety of integrating these devices into daily medical practice.

  View details for DOI 10.1007/s10916-012-9903-6

  View details for Web of Science ID 000315681600005

  View details for PubMedID 23321961

  View details for PubMedCentralID PMC4057035

• Smartphone App Use Among Medical Providers in ACGME Training Programs JOURNAL OF MEDICAL SYSTEMS Franko, O. I., Tirrell, T. F. 2012; 36 (5): 3135-3139

  Abstract

  The past decade has witnessed the advent of the smartphone, a device armed with computing power, mobility and downloadable "apps," that has become commonplace within the medical field as both a personal and professional tool. The popularity of medically-related apps suggests that physicians use mobile technology to assist with clinical decision making, yet usage patterns have never been quantified. A digital survey examining smartphone and associated app usage was administered via email to all ACGME training programs. Data regarding respondent specialty, level of training, use of smartphones, use of smartphone apps, desired apps, and commonly used apps were collected and analyzed. Greater than 85% of respondents used a smartphone, of which the iPhone was the most popular (56%). Over half of the respondents reported using apps in their clinical practice; the most commonly used app types were drug guides (79%), medical calculators (18%), coding and billing apps (4%) and pregnancy wheels (4%). The most frequently requested app types were textbook/reference materials (average response: 55%), classification/treatment algorithms (46%) and general medical knowledge (43%). The clinical use of smartphones and apps will likely continue to increase, and we have demonstrated an absence of high-quality and popular apps despite a strong desire among physicians and trainees. This information should be used to guide the development of future healthcare delivery systems; expanded app functionality is almost certain but reliability and ease of use will likely remain major factors in determining the successful integration of apps into clinical practice.

  View details for DOI 10.1007/s10916-011-9798-7

  View details for Web of Science ID 000307994400042

  View details for PubMedID 22052129

• Human skeletal muscle biochemical diversity JOURNAL OF EXPERIMENTAL BIOLOGY Tirrell, T. F., Cook, M. S., Carr, J., Lin, E., Ward, S. R., Lieber, R. L. 2012; 215 (15): 2551-2559

  Abstract

  The molecular components largely responsible for muscle attributes such as passive tension development (titin and collagen), active tension development (myosin heavy chain, MHC) and mechanosensitive signaling (titin) have been well studied in animals but less is known about their roles in humans. The purpose of this study was to perform a comprehensive analysis of titin, collagen and MHC isoform distributions in a large number of human muscles, to search for common themes and trends in the muscular organization of the human body. In this study, 599 biopsies were obtained from six human cadaveric donors (mean age 83 years). Three assays were performed on each biopsy - titin molecular mass determination, hydroxyproline content (a surrogate for collagen content) and MHC isoform distribution. Titin molecular mass was increased in more distal muscles of the upper and lower limbs. This trend was also observed for collagen. Percentage MHC-1 data followed a pattern similar to collagen in muscles of the upper extremity but this trend was reversed in the lower extremity. Titin molecular mass was the best predictor of anatomical region and muscle functional group. On average, human muscles had more slow myosin than other mammals. Also, larger titins were generally associated with faster muscles. These trends suggest that distal muscles should have higher passive tension than proximal ones, and that titin size variability may potentially act to 'tune' the protein's mechanotransduction capability.

  View details for DOI 10.1242/jeb.069385

  View details for Web of Science ID 000306605200010

  View details for PubMedID 22786631

  View details for PubMedCentralID PMC3394665

• Moment arms of the human digital flexors JOURNAL OF BIOMECHANICS Franko, O. I., Winters, T. M., Tirrell, T. F., Hentzen, E. R., Lieber, R. L. 2011; 44 (10): 1987-1990

  Abstract

  For the extrinsic hand flexors (flexor digitorum profundus, FDP; flexor digitorum superficialis, FDS; flexor pollicis longus, FPL), moment arm corresponds to the tendon's distance from the center of the metacarpalphalangeal (MP), proximal interphalangeal (PIP), or distal interphalangeal (DIP) joint. The clinical value of establishing accurate moment arms has been highlighted for biomechanical modeling, the development of robotic hands, designing rehabilitation protocols, and repairing flexor tendon pulleys (Brand et al., 1975; An et al., 1983; Thompson and Giurintano, 1989; Deshpande et al., 2010; Wu et al., 2010). In this study, we define the moment arms for all of the extrinsic flexor tendons of the hand across all digital joints for all digits in cadaveric hands.

  View details for DOI 10.1016/j.jbiomech.2011.04.025

  View details for Web of Science ID 000293048000023

  View details for PubMedID 21561624

  View details for PubMedCentralID PMC3124620

• Resonance Raman Studies of the (His)(Cys)₃ 2Fe-2S Cluster of MitoNEET: Comparison to the (Cys)₄ Mutant and Implications of the Effects of pH on the Labile Metal Center BIOCHEMISTRY Tirrell, T. F., Paddock, M. L., Conlan, A. R., Smoll, E. J., Nechushtai, R., Jennings, P. A., Kim, J. E. 2009; 48 (22): 4747-4752

  Abstract

  MitoNEET is a 2Fe-2S outer mitochondrial membrane protein that was initially identified as a target for anti-diabetic drugs. It exhibits a novel protein fold, and in contrast to other 2Fe-2S proteins such as Rieske proteins and ferredoxins, the metal clusters in the mitoNEET homodimer are each coordinated by one histidine residue and three cysteine residues. The interaction of the ligating His87 residue with the 2Fe-2S moiety is especially significant because previous studies have shown that replacement with Cys in the H87C mutant stabilizes the cluster against release. Here, we report the resonance Raman spectra of this naturally occurring Fe(2)S(2)(His)(Cys)(3) protein to assess local structural changes associated with cluster lability. Comparison of mitoNEET to its ferredoxin-like H87C mutant indicates that Raman peaks in the approximately 250-300 cm(-1) region of mitoNEET are influenced by the Fe-His87 moiety. Systematic pH-dependent resonance Raman spectral changes were observed in this spectral region for native mitoNEET but not the H87C mutant. The approximately 250-300 cm(-1) region of native mitoNEET is also sensitive to phosphate buffer. Thus, conditions that influence cluster release are shown here to concomitantly affect the resonance Raman spectrum in the region with Fe-His contribution. These results support the hypothesis that the Fe-N(His87) interaction is modulated within the physiological pH range, and this modulation may be critical to the function of mitoNEET.

  View details for DOI 10.1021/bi900028r

  View details for Web of Science ID 000266601500010

  View details for PubMedID 19388667

  View details for PubMedCentralID PMC2861891

• Cyclometalated iridium(III)-sensitized titanium dioxide solar cells PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES Mayo, E. I., Kilsa, K., Tirrell, T., Djurovich, P. I., Tamayo, A., Thompson, M. E., Lewis, N. S., Gray, H. B. 2006; 5 (10): 871-873

  Abstract

  Ir(III) dyes used as sensitizers in dye-sensitized solar cells produced quantum yields approaching unity for conversion of absorbed photons to current under simulated air mass 1.0 sunlight, with current production resulting from ligand-to-ligand charge-transfer states, rather than the typical metal-to-ligand charge-transfer states in ruthenium-based cells.

  View details for DOI 10.1039/b608430c

  View details for Web of Science ID 000240999400002

  View details for PubMedID 17019464