Clinical Focus

  • Pediatric Gastroenterology

Academic Appointments

Administrative Appointments

  • Medical Director Motility Program, Lucile Packard Children's Hospital (2021 - Present)

Professional Education

  • Board Certification: American Board of Pediatrics, Pediatric Gastroenterology (2019)
  • Board Certification: American Board of Pediatrics, Pediatrics (2017)
  • Fellowship: Children's Hospital Los Angeles Pediatric Gastroenterology (2019) CA
  • Residency: Phoenix Children's Hospital Pediatric Residency (2016) AZ
  • Medical Education: Virginia Commonwealth University School of Medicine Registrar (2013) VA

All Publications

  • Nutrition in children with exocrine pancreatic insufficiency. Frontiers in pediatrics Zheng, Y., Mostamand, S. 2023; 11: 943649


    Exocrine pancreatic insufficiency (EPI) is a condition defined as pancreatic loss of exocrine function, including decreased digestive enzymes and bicarbonate secretion, which leads to maldigestion and malabsorption of nutrients. It is a common complication in many pancreatic disorders. If left undiagnosed, EPI can cause poor digestion of food, chronic diarrhea, severe malnutrition and related complications. Nutritional status and fat-soluble vitamins should be carefully assessed and monitored in patients with EPI. Early diagnosis of EPI is clinically important for appropriate nutritional support and initiating pancreatic enzyme replacement therapy (PERT) which could significantly improve patient outcomes. The evaluation of nutritional status and related unique management in children with EPI will be discussed in this review.

    View details for DOI 10.3389/fped.2023.943649

    View details for PubMedID 37215591

  • Per Oral Endoscopic Myotomy (POEM) for pediatric achalasia: Institutional experience and outcomes JOURNAL OF PEDIATRIC SURGERY Petrosyan, M., Mostammand, S., Shah, A. A., Darbari, A., Kane, T. D. 2022; 57 (11): 728-735


    The surgical treatment of achalasia by both laparoscopic and endoscopic approaches has been recognized as the definitive management in children. Despite reported low volumes in many centers, there has been an increasing worldwide experience with endoscopic approaches to pediatric achalasia. The aim of this study is to report our institutional experience with per oral endoscopic myotomy (POEM) as first-line or revisional therapy for achalasia.An IRB approved retrospective review of all patients who underwent operative procedures for achalasia, specifically with the POEM technique, from July 2015 to September 2021. Data including demographics, intra-operative details, pre and post operative Eckardt scores, complications, outcomes, and follow-up were obtained.During the study period, a total of 43 children underwent 46 operations for achalasia including POEM and laparoscopic Heller myotomy (LHM). Operations included 37 POEMS (33 primary POEMS; 3 POEMS after failed LHM; and 1 POEM after failed POEM). Additionally, 9 LHM operations including, 4 primary LHM; 3 attempted POEMS converted to LHM; 1 attempted POEM after failed LHM converted to redo LHM; and 1 LHM after failed POEM. In the POEM group (n = 37), based on the high resolution esophageal manometry findings Chicago Classification types at diagnosis were as follows: 9 patients were type I (24.3%); 25 patients were type II (67.6%); 2 patients were type III (5.9%) and 1 patient was unknown type (2.7%). Sixteen children (43.2%) had prior endoscopic treatment of achalasia prior to POEM [Pneumatic Balloon Dilatation (PBD), and/or Botox injection (BTI)],), while prior operative intervention occurred in 4 patients (10.8%), 3 LHM and 1 POEM. Age at operation was 2-18 years (mean ± SD age: 11.6 ± 4.5 years). Weight at operation 11.8-100.7 kg (mean ± SD kg; 39 ± 19.9 kg). Range of baseline Eckardt score was 4-10 (mean ± SD: 6.73 ± 1.5). Operative time was 64-359 min (mean ± SD minutes: 138.1 ± 62.2 min). Intraoperative complications occurred in 16 patients (43.2%) but did not require reoperation during index admission including: 4 mucosotomy (11.8%); 9 pneumothoraces (24.3%); 2 pneumomediastinum (5.4%); 10 pneumoperitoneum (27%); 0 sub-mucosal tunnel bleeding (0%); 0 open conversion/death (0%). Post operative complications included: 5 recurrent dysphagia (13.5%); 0 esophageal leak (0%); 3 GERD (8.1%); 1 failed POEM (2.7%). Median length of stay was 2 days (mean ± SD days: 2.4 ± 0.9 day). Follow-up ranged from 1 to 74 months (median 15 months), mean follow-up 22.6 months ± 20 months. Post POEM Eckardt score was 0.6 ± 0.9. Five patients required a single PBD post POEM (13.5%) and 1 patient required a repeat myotomy (LHM) after POEM (2.7%) for a 16.2% reintervention rate. Subsequent normalization of Eckardt scores (≤ 3) and symptomatic relief was achieved in all patients (100%).POEM as first-line therapy for pediatric achalasia, or as a secondary procedure after failed prior myotomy or POEM, in our experience is safe and effective. We have shown equivalent results to our own prior experience with LHM. Long-term follow-up will be performed to monitor for recurrent symptoms, adequate physical growth, and general development.II.

    View details for DOI 10.1016/j.jpedsurg.2022.02.017

    View details for Web of Science ID 000875765100014

    View details for PubMedID 35361482

  • Pediatric Neurogastroenterology and Motility Services in North America: Neurogastroenterology and Motility Survey Report. Journal of pediatric gastroenterology and nutrition Patel, D., Safder, S. S., El-Chammas, K., Kapavarapu, P., Wheeler, J., Mostamand, S., Khlevner, J., Darbar, A. 2022; 74 (5): 593-598


    ABSTRACT: To characterize the current availability and scope of pediatric neurogastroenterology and motility (PNGM) services in North America (NA), the NASPGHAN-NGM committee distributed a self-reporting survey through the NASPGHAN bulletin board and mailing listserv, to compile a list of NA centers offering PNGM services, PNGM training, and the types of diagnostic and therapeutic PNGM procedures and services. We received responses that 54 centers in NA offer some form of PNGM services. Previously, the NASPGHAN website had last updated information from 2015 listing 36 centers in the USA and 2 in Canada. The American Neurogastroenterology and Motility Society (ANMS) website had 16 PNGM centers listed in NA in 2021. Neither of these resources capture additional information regarding training, research, advanced diagnostics, and therapeutics, and all available PNGM services. Our data highlights the growth in the field of PNGM services, and the variability of their distribution throughout the continent.

    View details for DOI 10.1097/MPG.0000000000003419

    View details for PubMedID 35192576