Shikib Mostamand

All Publications

• Pediatric High-Resolution Anorectal Manometry: Reference Ranges in 998 Children With Defecatory Disorders. Neurogastroenterology and motility Mostamand, S., Merchant, Q., Ji, Y., Boothroyd, D., Punati, J., Sicolo, A. R., Danialifar, T. 2026; 38 (6): e70371

  Abstract

  Anorectal manometry (ARM) is a commonly performed motility test in pediatrics. Currently, adult ARM normative data are extrapolated to pediatric assessments due to few validated pediatric studies. We share a single center experience of ARM performed in children with defecatory disorders across all age groups to highlight differences in measurements.This retrospective study reviewed 1001 ARM studies performed at Children's Hospital Los Angeles (CHLA) GI Motility Lab from 2012 to 2019, of which 998 studies met criteria for evaluation. They were stratified by gender (male, female) and age. Fifty-four patients with anorectal malformations were assessed independently. All studies were performed using high-resolution solid-state manometry catheters.The mean anal sphincter resting pressure (ASRP) for 944 patients without anorectal malformations was 75.6 ± 21.3 mmHg, with a statistically significant difference between male and female patients (male: 74.0 ± 20.9; female: 77.6 ± 21.3; p = 0.007). For each year of age, there is an estimated 0.23 mmHg increase in ASRP, but the result is not statistically significant (p = 0.082, CI: -0.03 to 0.49). In the subset of patients with anorectal malformations (n = 54), mean ASRP was 45.3 + 19.2 mmHg, without a significant difference between male or female.This is the largest pediatric study in patients with defecatory disorders demonstrating that mean ASRP does not vary with age from newborns to adolescents and is similar to adult values. Specific quantitative RAIR parameters such as latency, recovery, and duration require further studies in pediatrics.

  View details for DOI 10.1111/nmo.70371

  View details for PubMedID 42231615

• Overuse of reflux medications in Neonates. Seminars in perinatology Ratnasamy, K., Mostamand, S. 2025: 152160

  Abstract

  The diagnosis, management and differentiating of gastroesophageal reflux (GER) and pathologic gastroesophageal reflux disease (GERD) in infants remains a clinical challenge. There is significant clinical and economic burden attributed to GERD in the NICU leading to longer length of stays, higher financial costs, and overuse of medications.Current guidelines promote reduced reliance on acid suppression medication with shorter empiric trials (4 to 8 weeks) for the treatment of GERD, not attributing respiratory or laryngeal symptoms to GER due to a lack of diagnostic evidence, and a recommendation for trial of hydrolyzed formula before initiation of acid suppression. Few studies are demonstrating overall decrease use in all classes of medication for GERD, however, use of medications in infants remains high.Diagnostic challenges remain in pediatrics including interchangeable use of GER and GERD amongst clinicians, non-specific symptoms attributed to GERD, and lack of gold-standard diagnostic testing. Multichannel intraluminal impedance-pH monitoring (pH/MII) probes allow for an objective assessment of reflux episodes, reflux content, acidity, distance of reflux column or bolus direction, and symptom correlation.For any infant with a suspicion of GERD, priority should be made to take a thoughtful and complete history and physical exam, review of growth charts, and not only reviewing charted intake and output but observing feeding and episodes of reflux. A stepwise approach emphasizing non-pharmacological care, shared decision-making, and institutional-level stewardship remains essential to providing high-value care.

  View details for DOI 10.1016/j.semperi.2025.152160

  View details for PubMedID 41076374

• Median arcuate ligament syndrome: challenges, comorbidities, and controversies. Current opinion in pediatrics Mostamand, S. 2025; 37 (5): 447-451

  Abstract

  Median arcuate ligament syndrome (MALS) is understood to be a condition where compression of the celiac artery by the median arcuate ligament (MAL) may lead to symptoms of postprandial or exercise-induced abdominal pain, nausea, vomiting, diarrhea, oral aversion, and weight loss. This review summarizes recent literature on pediatric MALS while highlighting the challenges, comorbidities, and controversies encountered in this condition.The pathophysiologic mechanism by which MALS leads to pain is currently unknown. Several overlapping conditions are described in MALS, including mental health comorbidities to autonomic disorders such as orthostatic intolerance, POTS, or Ehlers-Danlos syndrome. Comorbid gastrointestinal conditions may include gastroesophageal reflux disease (GERD), inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), and gastroparesis. This overlap makes it difficult to distinguish the cause of broad symptoms patients may experience. MALS remains a complex and controversial topic with particular challenges in consensus diagnostic criteria, normative values in children, symptom definition or correlation, patient selection, predictive outcomes, or long-term follow-up data.Patients with MALS deserve a comprehensive multidisciplinary team to address their health. There is also a desperate need for collaborative research including randomized control trials in adults and a multicenter patient registry.

  View details for DOI 10.1097/MOP.0000000000001503

  View details for PubMedID 40904246

• Pediatric advanced complex endoscopy team enhances endoscopy quality and provider satisfaction. Journal of pediatric gastroenterology and nutrition Barakat, M. T., Bass, D., Goyal, A., Fink, C., Mostamand, S., Gugig, R. 2024

  Abstract

  Therapeutic endoscopic procedures are increasingly necessary for children. Pediatric gastroenterologist training and experience with endoscopic hemostasis and other complex therapeutic endoscopy procedures are often limited. We evaluated the impact of the implementation of an advanced complex endoscopy (ACE) team, which provides 24/7 inpatient/outpatient back-up endoscopy support.We analyzed hemostasis quality outcomes in the 2 years before implementation of ACE (2018-2020) versus the year following the implementation of ACE (2020-2021). We analyzed pediatric gastroenterology provider satisfaction and perspectives with a survey that was distributed to faculty, fellows, and advanced practice providers 1 month before implementation of ACE and again 12 months following ACE implementation.Endoscopy volume and outcome metrics for hemostasis procedures, including latency to endoscopy, need for reintervention, and administration/diversity of hemostatic therapy, including multimodal therapy, improved in the year following implementation of the ACE (p < 0.05 for each). Survey results demonstrated a positive impact on provider endoscopy experience and high utilization of ACE. Twenty-two percent of providers reported activating ACE in the prior month and 66% in the prior year. Most providers who activated ACE were very satisfied (85%) or satisfied (7.7%). Eighty-three percent noted ACE had a positive impact on inpatients, and 50% noted a positive impact on outpatient endoscopy. Provider anxiety with endoscopy diminished post-ACE implementation (62% vs. 28%). Respondents unanimously found ACE beneficial to patient care (100%).ACE implementation was associated with improved provider perspectives surrounding endoscopy and significant improvement in hemostasis quality parameters, escalation of hemostasis procedure volume, and broadening the range of hemostasis interventions.

  View details for DOI 10.1002/jpn3.12325

  View details for PubMedID 39073140

• Pilot data on a pre-attending rotation for pediatric gastroenterology fellows. Journal of pediatric gastroenterology and nutrition Christofferson, M., Carver, M., Chepuri, B., Mostamand, S., Abu El Haija, M. 2024

  View details for DOI 10.1002/jpn3.12243

  View details for PubMedID 38747038

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

  Abstract

  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

  Abstract

  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

  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