Newly Developed Evaluation of Esophageal Wall Motion Using Endoscopic Ultrasonography via Transnasal Endoscopy: Clinical Application in Esophageal Achalasia

INTRODUCTION: A new minimally invasive method is needed to evaluate both esophageal muscle contraction and esophageal wall distensibility under physiological conditions. The primary objective of this study was to establish a novel examination method for evaluating esophageal wall motion using a transnasal endoscope with an endoscopic ultrasonography (EUS) probe. The secondary objective was to apply this method to gain new pathophysiological insights into the clinical subtypes of achalasia diagnosed by high-resolution manometry. METHODS: The study included 20 patients with dysphagia. Patients were instructed to swallow 20 mL of oral rehydration solution, while a transnasal endoscope and a 20-MHz EUS probe were used to record the swallowing motion. The esophageal lumen area and muscle layer thickness were measured on still images from recorded videos. The reproducibility of the method was evaluated for both internal and external consistency. The study also analyzed differences in esophageal wall motion among achalasia subtypes using two new parameters: the muscle layer contraction rate and the esophageal wall distension rate. RESULTS: The new transnasal EUS method was safely performed in all 20 patients without complications, and the images were sufficient for analysis. The reproducibility evaluation showed significant positive correlations for both internal and external reproducibility. The esophageal wall distensibility and muscle layer contraction rates differed between esophageal achalasia subtypes. CONCLUSION: This pilot study successfully established a new, safe, and reproducible method for evaluating esophageal wall motion using transnasal EUS. This method will lead to a deeper understanding of the pathophysiology of esophageal motility disorders and potentially to the development of new treatment strategies.