Transoral endoscopic esophageal myotomy based on esophageal function testing in a survival porcine model

Background: The most effective treatment of achalasia is Heller myotomy. Objective: To explore a submucosal endoscopic myotomy technique tailored on esophageal physiology testing and to compare it with the open technique. Design: Prospective acute and survival comparative study in pigs (n = 12; 35 kg). Setting: University animal research center. Intervention: Eight acute-4 open and 4 endoscopic myotomies followed by 4 survival endoscopic procedures. Main Outcome Measurements: Preoperative and postoperative manometry; esophagogastric junction (EGJ) distensibility before and after selective division of muscular fibers at the EGJ and after the myotomy was prolonged to a standard length by using the EndoFLIP Functional Lumen Imaging Probe (Crospon, Galway, Ireland). Results: All procedures were successful, with no intraoperative and postoperative complications. In the survival group, the animals recovered promptly from surgery. Postoperative manometry demonstrated a 50% drop in mean lower esophageal sphincter pressure (LESp) in the endoscopic group (mean preoperative LESp, 22.2 +/- 3.3 mm Hg; mean postoperative LESp, 11.34 +/- 2.7 mm Hg; P < .005) and a 69% loss in the open procedure group (mean preoperative LESp, 24.2 +/- 3.2 mm Hg; mean postoperative LESp, 7.4 +/- 4 mm Hg; P < .005). The EndoFLIP monitoring did not show any distensibility difference between the 2 techniques, with the main improvement occurring when the clasp circular fibers were taken. Limitations: Healthy animal model; small sample. Conclusion: Endoscopic submucosal esophageal myotomy is feasible and safe. The lack of a significant difference in EGJ distensibility between the open and endoscopic procedure is very appealing. Were it to be perfected in a human population, this endoscopic approach could suggest a new strategy in the treatment of selected achalasia. patients. (Gastrointest Endosc 2011;73.111-6.)