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Research and education are foundational to the mission of Orlando Health and our Weight Loss and Bariatric Surgery Institute. Our physicians share their research and clinical insights with a national and international community of colleagues.




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Author(s) Title Description Publish Date
Barham K Abu Dayyeh, Fateh Bazerbachi, Eric J Vargas, Reem Z Sharaiha, Christopher C Thompson, Bradley C Thaemert, Andre F Teixeira, Christopher G Chapman, Vivek Kumbhari, Michael B Ujiki, Jeanette Ahrens, Courtney Day, MERIT Study Group, Manoel Galvao Neto, Natan Zundel, Erik B Wilson Endoscopic sleeve gastroplasty for treatment of class 1 and 2 obesity (MERIT): a prospective, multicentre, randomised trial BACKGROUND: Endoscopic sleeve gastroplasty (ESG) is an endolumenal, organ-sparing therapy for obesity, with wide global adoption. We aimed to explore the efficacy and safety of ESG with lifestyle modifications compared with lifestyle modifications alone. 7/31/2022
Ana F G Greco, José O Rossi, Joaquim J Barroso, Fernanda S Yamasaki, André F Teixeira, Elizete G L Rangel, Lauro P S Neto, Edl Schamiloglu Analysis of the sharpening effect in gyromagnetic nonlinear transmission lines using the unidimensional form of the Landau-Lifshitz-Gilbert equation Continuous nonlinear transmission lines (NLTLs), also known as gyromagnetic lines, consist of ferrite-based magnetic cores biased by an external magnetic field. Over the past years, many analytical and experimental studies have predicted the rise time reduction of the input pulse to the range of a f... 7/1/2022
David Motola, Ibrahim M Zeini, Rena C Moon, Muhammad Ghanem, Andre F Teixeira, Muhammad A Jawad ANTI-REFLUX PROCEDURES AFTER ROUX-EN-Y GASTRIC BYPASS CONCLUSIONS: Female patients with a significant weight loss may develop a severe reflux symptoms years after RYGB. Complaints of reflux after RYGB should not be overlooked. Careful follow-up and appropriate treatment (including surgical intervention) is needed for this population. 1/12/2022
Muhammad Ghanem, Mohamad Zuheir Al Kazzaz, Alnour Soliman Hydatid cyst in the neck, an unusual localization of the disease: A case report CONCLUSION: Hydatid cyst disease in the neck is extremely rare. Hydatid cyst should be included in differential diagnosis of cystic lesions in the neck especially in patients from endemic countries. Post-operative surveillance is important to diagnose the complete healing or recurrence of hydatid di... 8/14/2021
Rena C Moon, Andre F Teixeira, Muhammad A Jawad To oversew or not to oversew in robotic sleeve gastrectomy: a case against oversewing the staple line CONCLUSIONS: No significant difference in major complications was found between RSG patients with and without oversewn staple lines. Oversewing of the staple line may be associated with increased emergency room visits. 3/26/2021
Manoel Galvão Neto, Lyz Bezerra Silva, Luiz Gustavo de Quadros, Eduardo Grecco, Admar Concon Filho, Artagnan Menezes Barbosa de Amorim, Marcelo Falcao de Santana, Newton Teixeira Dos Santos, Joao Henrique Felicio de Lima, Thiago Ferreira de Souza, Helmut Wagner Poti de Morais, Felipe Matz Vieira, Rena Moon, André F Teixeira, Brazilian Endoscopic Sleeve Gastroplasty Collaborative Brazilian Consensus on Endoscopic Sleeve Gastroplasty CONCLUSIONS: This consensus establishes practical guidelines for performance of ESG. The experience of 1828 procedures shows the expertise of the selected specialists participating in this consensus statement. The group's experience has a satisfactory weight loss with low adverse events rate. The ma... 8/21/2020
Rena C Moon, Andre F Teixeira, Jessica Treto, Muhammad A Jawad Cardiopexy at the Time of Sleeve Gastrectomy as a Preventive Measure for Reflux CONCLUSION: Cardiopexy was not associated with a reduced rate of symptomatic GERD and conversion to RYGB after 6 months. 6/5/2020
Rena C Moon, Ana R Segura, Andre F Teixeira, Muhammad A Jawad Feasibility and safety of robot-assisted bariatric conversions and revisions CONCLUSIONS: Robot-assisted conversions and revisions were as feasible and safe as laparoscopic procedures. However, operative time was longer in robot-assisted conversions. 5/20/2020
Rena C Moon, Aaron Bornstein, Andre F Teixeira, Muhammad A Jawad Short-term results of long biliopancreatic limb Roux-en-Y gastric bypass-is it superior? CONCLUSIONS: Short-term results show that long biliopancreatic limb RYGB was not associated with a more significant weight loss after RYGB. The 2 procedures were similar in 30-day complications. 1/29/2020
Rena C Moon, Layth Alkhairi, Alyssa Jameson Wier, Andre F Teixeira, Muhammad A Jawad Conversions of Roux-en-Y gastric bypass to duodenal switch (SADI-S and BPD-DS) for weight regain CONCLUSION: Conversions of RYGB to SADI-S and BPD-DS can provide significant additional weight loss. However, complications and malnutrition can develop after the conversion, and further research is needed for evaluating safety. 10/23/2019
Manoel Galvao Neto, Rena C Moon, Luiz Gustavo de Quadros, Eduardo Grecco, Admar Concon Filho, Thiago Ferreira de Souza, Luis Augusto Mattar, Jose Americo Gomides de Sousa, Barham K Abu Dayyeh, Helmut Morais, Felipe Matz, Muhammad A Jawad, Andre F Teixeira Safety and short-term effectiveness of endoscopic sleeve gastroplasty using overstitch: preliminary report from a multicenter study CONCLUSION: Short-term results suggest that ESG is a safe and effective option for patients with Class I and II obesity. 10/19/2019
Li Ge, Rena C Moon, Ha Nguyen, Luiz Gustavo de Quadros, Andre F Teixeira, Muhammad A Jawad Pathologic findings of the removed stomach during sleeve gastrectomy CONCLUSION: Patients with gastroesophageal reflux and hyperlipidemia might suggest higher incidence rate of gastric histopathologic abnormalities. Routine preoperative screening may not be beneficial for patients undergoing sleeve gastrectomy. 2/17/2019
Rena C Moon, Linda Lastrapes, Jameson Wier, Mark Nakajima, Wyatt Gaskins, Andre F Teixeira, Muhammad A Jawad Preoperative Transversus Abdominis Plane (TAP) Block with Liposomal Bupivacaine for Bariatric Patients to Reduce the Use of Opioid Analgesics CONCLUSION: The use of preoperative TAP block with liposomal bupivacaine significantly decreased the use of IV and oral opioid analgesics. A larger prospective study may be needed to further validate the results. 1/21/2019
Nilson Rodrigues-Silva, Afonso F Canuto, Diogo F Oliveira, André F Teixeira, Oscar F Santos-Amaya, Marcelo C Picanço, Eliseu J G Pereira Negative cross-resistance between structurally different Bacillus thuringiensis toxins may favor resistance management of soybean looper in transgenic Bt cultivars High adoption rates of single-gene Bacillus thuringiensis (Bt) Cry1Ac soybean impose selection pressure for resistance in the soybean looper, Chrysodeixis includens, a major defoliator in soybean and cotton crops. To anticipate and characterize resistance profiles that can evolve, soybean looper lar... 1/19/2019
Rena C Moon, Vincent Kirkpatrick, Lori Gaskins, Andre F Teixeira, Muhammad A Jawad Safety and effectiveness of single- versus double-anastomosis duodenal switch at a single institution CONCLUSIONS: SADI-S and double-anastomosis DS are comparable in terms of weight loss and complication rate. However, close nutritional follow-up is warranted for both procedures. 1/5/2019
Rena C Moon, Aura Sofia Fuentes, Andre F Teixeira, Muhammad A Jawad Conversions After Sleeve Gastrectomy for Weight Regain: to Single and Double Anastomosis Duodenal Switch and Gastric Bypass at a Single Institution CONCLUSION: Conversions of LSG to RYGB, double anastomosis DS, and SADI-S are safe and can provide significant additional weight loss. 9/26/2018
Rena C Moon, Andre F Teixeira, Lyz Bezerra, Helga Cristina Almeida Wahnon Alhinho, Josemberg Campos, Luiz Gustavo de Quadros, Artagnan Menezes Barbosa de Amorim, Manoel Galvao Neto, Muhammad A Jawad Management of Bariatric Complications Using Endoscopic Stents: a Multi-Center Study CONCLUSION: Stents may be useful and effective in managing complications after different bariatric procedures, including RYGB and LSG. 8/18/2018
Rena C Moon, Andre F Teixeira, Manoel Galvao Neto, Natan Zundel, Bruno Queiroz Sander, Flavio Mitidieri Ramos, Felipe Matz, Giorgio A Baretta, Luiz Gustavo de Quadros, Eduardo Grecco, Thiago Souza, Sergio A Barrichello, Admar Concon Filho, Eduardo Nobuyuki Usuy, Artagnan Menezes Barbosa de Amorim, Muhammad A Jawad Efficacy of Utilizing Argon Plasma Coagulation for Weight Regain in Roux-en-Y Gastric Bypass Patients: a Multi-center Study CONCLUSION: APC can be useful in reducing the regained weight after RYGB, and patients showed 6-10% total weight loss at 12 months. Randomized trials would be needed to validate the findings. 4/9/2018
Vincent Kirkpatrick, Rena C Moon, Andre F Teixeira, Muhammad A Jawad Cirrhosis following single anastomosis duodeno-ileal switch: A case report CONCLUSION: Close laboratory monitoring is important after SADI-S in order to detect worsening hepatic dysfunction, which may occur many years after the surgery in the absence of other etiologies for liver failure. 4/2/2018
Rena C Moon, Lori Gaskins, Andre F Teixeira, Muhammad A Jawad Safety and Effectiveness of Single-Anastomosis Duodenal Switch Procedure: 2-Year Result from a Single US Institution CONCLUSIONS: Loop DS seems to be effective in weight loss and is a feasible operation in the super-obese population. However, close monitoring of liver enzymes is warranted in addition to nutritional follow-up. 12/24/2017
Abbas Al-Kurd, Ronit Grinbaum, Ala'a Abubeih, Baha Siam, Muhammad Ghanem, Haggi Mazeh, Ido Mizrahi, Nahum Beglaibter Conversion of Laparoscopic Adjustable Gastric Banding to Gastric Bypass: a Comparison to Primary Gastric Bypass CONCLUSION: Albeit longer operating time, revision of LAGB to LRYGB is a safe procedure, with similar complication rates when compared to primary LRYGB. Although revisional LRYGB does result in less weight loss than primary LRYGB, the procedure's safety makes it a very plausible option as a rescue o... 12/6/2017
Rena C Moon, Muhammad Ghanem, Andre F Teixeira, Nestor De La Cruz-Munoz, Meredith K Young, Patrick Domkowski, Jason Radecke, Stephen G Boyce, Raul Rosenthal, Emmanuel Lo Menzo, David Gutierrez Blanco, David R Funes, Muhammad A Jawad Assessing risk factors, presentation, and management of portomesenteric vein thrombosis after sleeve gastrectomy: a multicenter case-control study CONCLUSION: Incidence of PMVT is low after sleeve gastrectomy. A personal history of malignancy and type 2 diabetes increase the risk of PMVT. Increasing abdominal pain in a context of dehydration is common presenting symptoms with diagnosis confirmed by computed tomography. Anticoagulation is the s... 11/28/2017
Rena C Moon, Ashley Frommelt, Andre F Teixeira, Muhammad A Jawad Comparison of Banded Versus Non-banded Roux-en-Y Gastric Bypass: a Series of 1150 Patients at a Single Institution CONCLUSIONS: Banded laparoscopic RYGB with a pericardial patch may not demonstrate a significant additional weight loss or prevent future weight regain. We were not able to demonstrate a clear advantage of banded RYGB over non-banded RYGB. 7/29/2017
Rena C Moon, Jameson Wier, Romulo Lind, Andre F Teixeira, Muhammad A Jawad Single-center experience in single-stage conversions of gastric banding to sleeve gastrectomy: is it as safe as 2-stage conversions? CONCLUSION: Single-stage laparoscopic conversion of LAGB to LSG is feasible and, in appropriately selected patients, does not seem to increase the risk of complications compared with 2-stage procedures. 2/25/2017
Muhammad A Jawad, Lars Nelson, Rena C Moon, Andre F Teixeira Techniques of Single-Stage Laparoscopic Conversion of Roux-en-Y Gastric Bypass to Single Anastomosis Bilio-pancreatic Diversion with Duodenal Switch CONCLUSION: Conversion of RYGB to single anastomosis duodenal switch can be a complicated operation, requiring a two-stage approach in most cases. With the adoption of the described technique, it can be easier to be achieved in a single-stage. 2/18/2017
Rena C Moon, Andre F Teixeira, Muhammad A Jawad Safety and effectiveness of anterior fundoplication sleeve gastrectomy in patients with severe reflux CONCLUSION: Anterior fundoplication sleeve gastrectomy may be a safe and effective alternative in obese patients with severe reflux who want to undergo sleeve gastrectomy. 11/28/2016
Muhammad A Jawad, Lars Nelson, Rena C Moon, Andre F Teixeira Robotic-Assisted Laparoscopic Biliopancreatic Diversion, Vertical Sleeve Gastrectomy with Traditional Roux-en-Y Duodenal Switch CONCLUSION: With the adoption of robots and the described technique, it can be easier to be achieved in less time. 10/21/2016
Lars Nelson, Rena C Moon, Andre F Teixeira, Manoel Galvão, Almino Ramos, Muhammad A Jawad SAFETY AND EFFECTIVENESS OF SINGLE ANASTOMOSIS DUODENAL SWITCH PROCEDURE: PRELIMINARY RESULT FROM A SINGLE INSTITUTION CONCLUSIONS: SADI-S is a feasible operation with a promising weight loss and diabetes resolution in the super-obese population. 9/30/2016
Josemberg Marins Campos, Flávio Coelho Ferreira, André F Teixeira, Jones Silva Lima, Rena C Moon, Marco Aurélio D'Assunção, Manoel Galvão Neto Septotomy and Balloon Dilation to Treat Chronic Leak After Sleeve Gastrectomy: Technical Principles CONCLUSIONS: Septotomy and balloon dilation were initially performed on a difficult-to-treat chronic fistula after gastric bypass and named before as stricturotomy (Campos JM, Siqueira LT, Ferraz AA, et al., J Am Coll Surg 204(4):711, 2007). This procedure allows internal drainage of the fistula and... 6/15/2016
Rena C Moon, Derek Stephenson, Nelson A Royall, Andre F Teixeira, Muhammad A Jawad Robot-Assisted Versus Laparoscopic Sleeve Gastrectomy: Learning Curve, Perioperative, and Short-Term Outcomes CONCLUSIONS: Our study showed similar 30-day readmission and reoperation rate between LSG and RA-LSG during the learning curve and after the proficiency has been achieved. 3/20/2016
Josemberg Marins Campos, Rena C Moon, Galeno E J Magalhães Neto, Andre F Teixeira, Muhammad A Jawad, Lyz Bezerra Silva, Manoel Galvão Neto, Álvaro Antônio B Ferraz Endoscopic treatment of food intolerance after a banded gastric bypass: inducing band erosion for removal using a plastic stent CONCLUSIONS: Endoscopic removal of the ring using SEPS appeared to be safe and effective after a banded RYGB. 3/17/2016
Rena C Moon, Lars Nelson, Andre F Teixeira, Muhammad A Jawad Outcomes of Roux-en-Y gastric bypass in the super obese: comparison of body mass index 50-60 kg/m(2) and≥60 kg/m(2) with the morbidly obese CONCLUSION: Readmission and reoperation rates were similar in the BMI 40-50, 50-60, and≥60 kg/m(2) groups. Super-obese and super-super-obese patients are not at greater risk for surgical complications compared with those with lower BMIs. 2/1/2016
Rena C Moon, Juan C Gutierrez, Nelson A Royall, Andre F Teixeira, Muhammad A Jawad Robotic Roux-en-Y Gastric Bypass, is it Safer than Laparoscopic Bypass? CONCLUSIONS: Robot-assisted Roux-en-Y gastric bypass may result in higher leak rate at the pouch level, when compared to that of laparoscopic procedures. 9/21/2015
Lars Nelson, Rena C Moon, Andre F Teixeira, Muhammad A Jawad Methylene Blue or Upper GI, Which is More Effective for Detecting Leaks in Gastric Bypass Patients? CONCLUSIONS: UGI studies and methylene blue challenges had no significant difference in detecting a postoperative leak. Furthermore, these tests may have limited utility and may warrant adjuncts to aid in leak detection. 8/14/2015
Lyz Bezerra Silva, Rena C Moon, Andre F Teixeira, Muhammad A Jawad, Álvaro Antônio Bandeira Ferraz, Manoel Galvão Neto, Almino Cardoso Ramos, Josemberg Marins Campos Gastrobronchial Fistula in Sleeve Gastrectomy and Roux-en-Y Gastric Bypass--A Systematic Review Gastrobronchial fistula (GBF) is a rare surgical complication after bariatric surgery. We aimed to identify the clinical aspects of GBF and establish diagnostic and treatment strategies. A literature search was conducted in December 2013, in the PubMed electronic database. Eleven studies were select... 7/31/2015
Rena C Moon, Flavio Kreimer, Andre F Teixeira, Josemberg M Campos, Alvaro Ferraz, Muhammad A Jawad Morbidity Rates and Weight Loss After Roux-en-Y Gastric Bypass, Sleeve Gastrectomy, and Adjustable Gastric Banding in Patients Older Than 60 Years old: Which Procedure to Choose? CONCLUSIONS: LSG showed the lowest readmission and reoperation rate, and RYGB patients had the highest mortality rate. Weight loss and comorbidity resolution were effectively achieved in RYGB and LSG patients. 7/30/2015
Lars Nelson, Rena C Moon, Andre F Teixeira, Muhammad A Jawad Duodenal stump leak following a duodenal switch: A case report CONCLUSION: Duodenal stump leaks must be diagnosed as early as possible, and treated appropriately with operative intervention. Regardless of the operative technique the key to appropriate treatment is stabilize the patient, repair the duodenal stump, and adequate drainage. 7/27/2015
Rena C Moon, Ashley Frommelt, Andre F Teixeira, Muhammad A Jawad Indications and outcomes of reversal of Roux-en-Y gastric bypass CONCLUSIONS: Reversal of RYGB to normal anatomy is reasonable in patients with severe or refractory complications. 4/13/2015
Rena C Moon, Nimesh Shah, Andre F Teixeira, Muhammad A Jawad Management of staple line leaks following sleeve gastrectomy CONCLUSION: Management of leaks after LSG can be challenging. Early diagnosis and treatment is important in the management of a leak. However, it can be treated safely via various management options depending on the time of diagnosis and size of the leak. 12/31/2014
Rena C Moon, Andre F Teixeira, Muhammad A Jawad Is preoperative manometry necessary for evaluating reflux symptoms in sleeve gastrectomy patients? CONCLUSION: Manometric study may be necessary in LSG patients to accurately evaluate GERD and the LES pressure. 12/31/2014
Ido Mizrahi, Nahum Beglaibter, Natalia Simanovsky, Natali Lioubashevsky, Haggi Mazeh, Muhammad Ghanem, Katya Chapchay, Ahmed Eid, Ronit Grinbaum Ultrasound evaluation of visceral and subcutaneous fat reduction in morbidly obese subjects undergoing laparoscopic gastric banding, sleeve gastrectomy, and Roux-en-Y gastric bypass: a prospective comparison study CONCLUSION: LSG and LRYGB show better preferential and overall VF reduction than LAGB. US may serve as a simple tool of evaluating postoperative fat distribution. 11/15/2014
Christopher DuCoin, Rena C Moon, Mertalaine Mulatre, Andre F Teixeira, Muhammad A Jawad Safety and effectiveness of Roux-en-Y gastric bypass in patients between the ages of 17 and 19 CONCLUSION: LRYGB in younger patients almost the age of 20 is both safe and effective when compared to matched adults in regard to weight loss, comorbid condition, and complications. 7/30/2014
Derek Stephenson, Rena C Moon, Andre F Teixeira, Muhammad A Jawad Intussusception after Roux-en-Y gastric bypass CONCLUSION: While reduction alone of the intussusception is safe and effective, there is a risk of recurrence, and imbrication of the J-J anastomosis may be a more effective means of treatment. 6/18/2014
Christopher DuCoin, Rena C Moon, Andre F Teixeira, Muhammad A Jawad Laparoscopic choledochoduodenostomy as an alternate treatment for common bile duct stones after Roux-en-Y gastric bypass CONCLUSION: This small case series suggests that, in experienced hands, laparoscopic choledochoduodenostomy is an option for safe and effective treatment of choledocholithiasis after gastric bypass. 6/11/2014
Rena C Moon, Andre F Teixeira, Michael Goldbach, Muhammad A Jawad Management and treatment outcomes of marginal ulcers after Roux-en-Y gastric bypass at a single high volume bariatric center CONCLUSION: Despite the use of routine PPI, the incidence of MU was not insignificant. A significant portion of patients required surgical treatment. Perforations can be effectively managed by oversewing of the ulcer. 1/28/2014
Rena C Moon, Andre F Teixeira, Muhammad A Jawad Treatment of weight regain following roux-en-Y gastric bypass: revision of pouch, creation of new gastrojejunostomy and placement of proximal pericardial patch ring In the literature, weight regain or failure of weight loss has been reported in up to 35% of patients after Roux-en-Y gastric bypass (RYGB). Several revisional procedures have been suggested to reinitiate further weight loss in this group of patients, and placing a silastic ring around the pouch pro... 1/22/2014
Ido Mizrahi, Abbas Alkurd, Muhammad Ghanem, Diaa Zugayar, Haggi Mazeh, Ahmed Eid, Nahum Beglaibter, Ronit Grinbaum Outcomes of laparoscopic sleeve gastrectomy in patients older than 60 years CONCLUSIONS: LSG is safe and very efficient in patients aged >60, despite higher rates of perioperative comorbidities. 1/21/2014
Luke Elms, Rena C Moon, Sheila Varnadore, Andre F Teixeira, Muhammad A Jawad Causes of small bowel obstruction after Roux-en-Y gastric bypass: a review of 2,395 cases at a single institution CONCLUSIONS: Our findings indicate a 3.9 % reoperation rate for abdominal pain and SBO, and more than 45 % of these patients had symptoms secondary to adhesions. Only 1.1 % of our laparoscopic RYGB patients developed internal herniation after closure of both internal hernia spaces. 1/2/2014
Rena C Moon, Andre F Teixeira, Christopher DuCoin, Sheila Varnadore, Muhammad A Jawad Comparison of cholecystectomy cases after Roux-en-Y gastric bypass, sleeve gastrectomy, and gastric banding CONCLUSIONS: Frequency of symptomatic gallstones after LRYGB and LSG was not significantly different and after LAGB was significantly lower. Slow and less amount of weight loss would have contributed to the low rate of symptomatic gallstone formation in the LAGB patients. 8/13/2013
Rena C Moon, Andre F Teixeira, Muhammad A Jawad Conversion of failed laparoscopic adjustable gastric banding: sleeve gastrectomy or Roux-en-Y gastric bypass? CONCLUSION: Converting LAGB to LSG and LRYGB both seem feasible and resulted in substantial further weight loss. 6/18/2013
Rena Moon, Andre Teixeira, Sheila Varnadore, Kelly Potenza, Muhammad A Jawad Reinforcing the staple line with Surgicel® Nu-knit® in Roux-en-Y gastric bypass: comparison with bovine pericardial strips CONCLUSIONS: The use of absorbable hemostat as buttress material may be effective in reducing acute postoperative bleeding in LRYGB at a significantly lower cost. 3/9/2013
Rena Moon, Andre Teixeira, Muhammad A Jawad Pericardial patch ring Roux-en-Y gastric bypass: a preliminary report CONCLUSIONS: Longer follow-up is needed to prove the true efficacy of this procedure in reducing weight gain. Pericardial patch ring RYGB seems to be a safe alternative for banded RYGB of other materials. 12/15/2012
Rena Moon, Andre Teixeira, Kelly Potenza, Muhammad A Jawad Routine gastrostomy tube placement in gastric bypass patients: impact on length of stay and 30-day readmission rate CONCLUSIONS: Routine gastrostomy tube placement in the gastric remnant at the time of RYGB seems to have contributed to our short LOS and low 30-day readmission rate. 12/1/2012
Ido Mizrahi, Haggi Mazeh, Yair Levy, Gilad Karavani, Muhammad Ghanem, Yaron Armon, Amos Vromen, Ahmed Eid, Raphael Udassin Comparison of pediatric appendectomy outcomes between pediatric surgeons and general surgery residents CONCLUSIONS: The results of this study suggest that the presence of a PS does not affect the outcomes of appendectomies. 5/15/2012