Biomechanics of the esophagogastric junction in gastroesophageal reflux disease.

Gastroesophageal reflux is inherently mechanical in nature, driven by the pressure difference between the stomach and the esophagus in the setting of a relaxed or hypotensive sphincter. Recent advances in our understanding of esophagogastric junction (EGJ) biomechanics in the etiology of gastroesophageal reflux disease are highlighted here. We focus this review on three critical areas: the anatomy and physiology of the EGJ that predispose the junction to reflux, the mechanical compliance of the EGJ musculature that has significant pathophysiologic underpinnings, and the trans-sphincteric pressure gradients during gastroesophageal reflux. We also examine the mechanistic basis of a higher incidence of reflux in obese patients and conclude with some observations on the future of understanding EGJ biomechanics.