Pediatric Esophageal Biomechanics and Remodeling: Integrating Distensibility and Compliance Beyond Luminal Diameter

Management of pediatric esophageal disease has traditionally relied on static anatomic endpoints including luminal diameter, endoscopic findings, and histologic features to guide diagnosis and therapeutic decision-making. However, these measures incompletely capture esophageal function and the biomechanical consequences of chronic inflammation, fibrosis, injury, and extrinsic compression. In adult gastroenterology, esophageal distensibility assessment using the functional lumen imaging probe (FLIP) has emerged as an adjunctive marker of disease severity and treatment response in conditions such as achalasia and eosinophilic esophagitis. This work reviews pediatric and adult literature examining esophageal distensibility, compliance, and biomechanical remodeling, with emphasis on FLIP-based assessment, disease-specific remodeling patterns, and implications for therapeutic endoscopy. Available evidence demonstrates that esophageal distensibility provides physiologic information beyond static luminal diameter and may help explain discordance between anatomic findings and symptoms. Pediatric studies support the feasibility of FLIP-based functional assessment and suggest that altered distensibility trajectories reflect disease-related remodeling in eosinophilic esophagitis, caustic injury, postsurgical strictures, and vascular compression. Functional measurements may also help interpret dilation response and identify situations in which additional size escalation alone may yield diminishing functional benefit. This review also proposes a pediatric framework integrating FLIP-derived biomechanics into interpretation of dysphagia, dilation response, and therapeutic decision-making. Esophageal distensibility and biomechanical remodeling represent underutilized actionable concepts in pediatric esophageal disease. Integrating functional assessment with anatomic evaluation may improve interpretation of disease severity, explain discordance between symptoms and luminal diameter, and inform therapeutic decision-making. Pediatric-specific interpretive frameworks are needed to determine how distensibility and compliance metrics can guide management in children.