Measurement of secondary esophageal motility by Endoluminal Functional Lumen Imaging Probe (EndoFLIP) in young patients with pediatric feeding disorder with and without persistent dysphagia

Pediatric feeding disorder (PFD) is defined as an impaired oral intake that is not age-appropriate, and is associated with medical, nutritional, feeding skill, and/or psychosocial dysfunction.1 Swallowing requires precise coordination of oropharyngeal and esophageal musculature, and disruption at any level may result in oropharyngeal dysphagia (OPD), which can present as gastrointestinal, otolaryngological, or pulmonary symptoms.2 While mucosal and anatomic abnormalities are commonly evaluated, gastrointestinal functional barriers to feeding in young children remain poorly characterized. One study demonstrated a similar prevalence of abnormal endoscopic biopsies in children with persistent feeding problems compared with controls, although the incidence of eosinophilic esophagitis (EoE) was higher in the feeding-disorder cohort.3 Given the multifactorial nature of PFD, early identification of esophageal motility abnormalities is critical; even mild disruptions in distensibility or motor function may drive symptoms and hinder progress with feeding therapies. Patients with PFD routinely undergo esophagogastroduodenoscopy (EGD) to evaluate for eosinophilic esophagitis (EoE) and gastroesophageal reflux disease (GERD); however, EGD does not provide information about esophageal function. High-resolution manometry (HRM), while informative, is challenging in young children because of catheter size, cooperation requirements, and swallowing demands, resulting in a significant diagnostic gap during early feeding development. The Endoluminal Functional Lumen Imaging Probe (EndoFLIP) is a minimally invasive tool that allows assessment of esophageal motility using a balloon-mounted catheter placed trans orally at the time of sedated EGD.4-6 The esophagogastric junction distensibility index (EGJ-DI) reflects how easily a segment of the gastrointestinal tract stretches in response to pressure, with lower values suggesting reduced compliance. Normal EndoFLIP parameters are defined only for adults, with EGJ-DI > 2.8 mm²/mmHg and EGJ diameter > 18 mm considered normal.7 No standardized normative data exist for the upper esophageal sphincter (UES) in adults or for either sphincter in children. EndoFLIP is FDA-approved for children aged ≥ 5 years, and prior studies have demonstrated safety in younger children.8, 9 EndoFLIP was adopted as standard of care within the motility program at Phoenix Children's Hospital (PCH) in May 2022. Observed improvement in OPD following EndoFLIP-guided UES dilation motivated this study. The primary objective was to describe esophageal motility patterns in children aged 6–72 months with PFD with and without dysphagia. The secondary objective was to characterize pediatric EndoFLIP baseline parameters. We hypothesized that UES restriction contributes to feeding difficulties in young children with PFD. This retrospective observational study included children ages 6–72 months diagnosed with PFD who underwent EGD with EndoFLIP between January 2023 and January 2025 at a tertiary pediatric feeding and aerodigestive referral center. Children with known motility disorders were excluded. EndoFLIP was performed under general anesthesia (without using Sevoflurane or Precedex) with appropriate catheter size (<5yo = 325 N/80 mm; >5yo = 322 N/160 mm) at the time of EGD. EndoFLIP balloon was filled to 10 cc to find LES on the three-dimensional geometric display on screen and narrowest area by sensor number was noted for consistency of measurements. We slowly filled in more volume in 5 or 10 cc volume increments to go safely below 50 mmHg. The catheter was held safely at the patient's lip to avoid it being pushed to the stomach with an increase in volume for accurate results. Upper and lower esophageal sphincter (UES and LES) baseline parameters—including diameter (D), volume (V), pressure (P), and distensibility index (DI)—were recorded. Abnormal LES DI was defined as <3 mm²/mmHg based on adult reference values.7 UES DI < 1 mm²/mmHg or decreasing DI with increasing pressure was considered abnormal and were referred for dilation with EsoFLIP and/or Botox. Presence and pattern of contractions, including rapid antegrade contractions (RAC) and rapid retrograde contractions (RRC), were documented. Each measurement was recorded in duplicate and averaged for analysis. Dysphagia was defined using a combination of clinical symptoms; including feeding aversion, refusal, spitting out food, pain, coughing, choking, and gagging; and objective findings from feeding evaluations and modified barium swallow (MBS) studies when available. Dysphagia severity was graded using the Dysphagia Outcome and Severity Scale (DOSS).10, 11 Descriptive statistics summarized demographics, clinical characteristics, and EndoFLIP findings. Exploratory comparisons between dysphagia and nondysphagia groups were performed using Fisher exact or Wilcoxon rank sum tests. Statistical significance was set at p < 0.05. Statistical analyses were performed using SAS (Statistical Analysis Software 9.4; SAS Institute Inc.) or R software (version 4.1.2; R Foundation for Statistical Computing). Among 150 children with PFD, 120 (80%) had clinically diagnosed dysphagia, including 113 (94.2%) with mild-to-moderate OPD on MBS (DOSS scores 2–5). Patient characteristics are summarized in Table 1. Children with dysphagia were younger than those without dysphagia (median 21.5 vs 28.5 months; p = 0.02) (Supporting Information: Table S1). Median LES DI was 3.70 mm²/mmHg with a diameter of 11.7 mm in the dysphagia group and 4.11 mm²/mmHg with a diameter of 12.7 mm in the non-dysphagia group (Supporting Information: Table S2). Relative to adult norms, both groups demonstrated lower median LES DI and diameter values.7 The distribution of LES and UES measurements is presented for dysphagia and non-dysphagia groups (Figure 1). Overall, 35 patients (23.5%) demonstrated abnormal esophageal contractility, 11 (7.4%) had LES restriction, and 43 (30.9%) exhibited UES restriction. UES restriction represented the most significant abnormality and was observed across both dysphagia and non-dysphagia groups. The presence or absence of dysphagia was not associated with the pattern of contractility (p > 0.05) (Supporting Information: Table S2). This is a first-of-its-kind study in pediatrics showing esophageal functional data with descriptive measurements as well as steps of the EndoFLIP protocol for children less than 5 years of age with PFD. Relative to adult norms, our cohort demonstrated lower median LES-DI and LES diameter measurements, representing novel observations not previously described in the literature.7 Dysphagia did not seem to impact patterns of sphincter and esophageal contractility in children. Adult-derived DI thresholds were used due to the absence of pediatric normative data; while pragmatic, these thresholds may not fully account for age-related physiological differences in muscle compliance. Importantly, our findings demonstrate clear differences between pediatric and adult measurements, underscoring the need for pediatric-specific reference values. A striking finding was the high prevalence of UES restriction, present in nearly one-third of patients. The observed UES abnormalities based on adult cutoffs, may reflect children's developmental immaturity, prematurity, altered neuromuscular coordination, striated muscle hypertonia, autoimmune issues, effect of sedation or normal variations in sphincter tone rather than fixed pathology. UES restriction can impede bolus transit and contribute to coughing, gagging, choking, and prolonged mealtimes in children with PFD. When unrecognized, these physiologic limitations may be misattributed to behavioral feeding difficulties, delaying effective treatment. EndoFLIP provides functional data not captured by EGD or MBS alone and highlights esophageal contributors to feeding dysfunction.3, 12 Our group is also preparing a second manuscript from this cohort, looking at clinical outcomes of treatment of UES restriction with EsoFLIP balloon dilation or Botox to understand the role of this motility abnormality as an active medical domain barrier to eating, versus a normal variant triggering behavioral adjustments. Strengths of this study include its novelty, standardized EndoFLIP protocol, and demonstration of procedural safety, with no adverse events reported in 150 procedures. Limitations include the absence of a healthy pediatric control group, reliance on adult reference values, a small sample size with statistical power likely insufficient to detect small differences between dysphagia and non-dysphagia groups rendering finding inconclusive. EndoFLIP is an easy-to-perform, safe, feasible, and informative adjunct to EGD in young children with PFD. A comprehensive evaluation incorporating MBS, EGD, and EndoFLIP may improve identification of esophageal functional barriers to feeding. Further prospective studies are needed to establish pediatric normative EndoFLIP values and to correlate functional abnormalities with clinical outcomes. The authors would like to acknowledge the assistance of Stephanie Villa-Niemczyk of the Phoenix. Children's Writing Core for providing critical review and editing of the manuscript. The study was supported by Griffin Connell Aerodigestive Research Fund. The authors declare no conflict of interest. This work was presented as an oral presentation at the 12th Annual International Pediatric Feeding Disorder Conference (IPFDC), Phoenix, Arizona in February 2025 and as a poster at Digestive Disease Week (DDW), San Diego, California in May 2025. Dr. Dana I Williams, MD accepts full responsibility for the conduct of the study. PCH institutional review board (IRB-24-397) approved the study. Informed consent was not needed and considered non-applicable for this retrospective study. This is a minimal risk study with no direct benefits for the study population. The indirect benefits could include the addition of data on EndoFLIP usage in the pediatric population with dysphagia as this is the first of its kind study, and no data is available in the literature related to this. Data for this study are available upon reasonable request. Interested researchers can contact the corresponding author to access de-identified participant data. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.