Hiatal Dysfunction in Achalasia Esophagus

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Project Summary: The sphincter mechanism at the lower end of the esophagus, lower esophageal sphincter plays a major role in the pathophysiology of esophageal motor disorders. An incompetent sphincter leads to reflux disease (weak sphincter or too much relaxation) and overtly competent sphincter (too little relaxation) leads to achalasia esophagus and possibly other motor disorders of the esophagus. Exact understanding of the lower esophageal sphincter has defied generations of investigators. Our studies, over a span of more than 35 years have revealed that the lower esophageal sphincter mechanism consists of 2 components, smooth muscle LES and skeletal muscle crural diaphragm (CD). Using “state of the art” techniques such as 3D-high resolution manometry along with static and dynamic CT scan imaging, our preliminary studies suggests that the crural diaphragm which forms the esophageal hiatus may play a crucial role in the pathogenesis of achalasia esophagus, a major motility disorder of the esophagus. The specific goals of the proposal are to define: 1) the 3D pressure profile of the EGJ in achalasia esophagus: extend our preliminary findings of anatomical and functional abnormalities of crural diaphragm in patients with achalasia esophagus, to study the crural diaphragm structure and function using MR imaging and crural diaphragm EMG recordings respectively. 2) To demonstrate lack of sliding, or in other words a tight anchoring between the LES and crural diaphragm in patients with achalasia esophagus. 3) We propose to study the effect of spine disc injury on the structure and function of the crus of diaphragm/hiatal muscle in an animal model: We will test a novel hypothesis that injury to the lumbar spine leads to pathological changes in the structure and function of the crus diaphragm muscle.