Anterior versus posterior peroral endoscopic myotomy: a prospective randomized controlled trial from a Thai tertiary center.

BACKGROUND/AIMS: Achalasia is an esophageal motility disorder. Peroral endoscopic myotomy is widely used for all subtypes; however, randomized head-to-head evidence comparing the anterior and posterior approaches remains limited. We compared efficacy, safety, and reflux outcomes. METHODS: We conducted a single-center, single-blind, prospective randomized controlled trial from February 2023 to August 2024. Twenty-eight patients with achalasia types I-III were randomized to anterior or posterior peroral endoscopic myotomy. The primary outcomes were esophageal acid exposure at 3 months (24-hour pH monitoring) and clinical success (Eckardt score ≤3). The secondary outcomes were procedural parameters, complications, timed barium esophagography, manometry, and reflux esophagitis. RESULTS: Baseline characteristics were comparable between the groups. Procedural metrics and complication rates were similar and mild, with no severe adverse events. At 12 months, both groups showed significant symptom relief, reduced Eckardt scores, and decreased lower esophageal sphincter pressure. Posterior myotomy yielded a higher proportion of abnormal DeMeester scores (57.1% vs. 28.6%, p=0.14), although reflux esophagitis remained mild and comparable between the groups. CONCLUSIONS: Posterior peroral endoscopic myotomy demonstrated comparable efficacy, safety, and reflux outcomes. The anterior approach improved clearance on timed barium esophagography; however, both approaches achieved durable symptom control with acceptable safety profiles, supporting posterior myotomy as a valid alternative.