A Randomized Controlled Trial Comparing Conventional and Short Submucosal Tunnel Techniques in Type II Achalasia

Achalasia type II is the most common manometric subtype and responds well to Peroral Endoscopic Myotomy (POEM). However, the optimal extent of submucosal tunneling and myotomy length for this population remains uncertain. Conventional POEM typically involves a 10-12 cm submucosal tunnel with a long esophageal myotomy (6-8 cm) and a 2-3 cm gastric extension. While effective, this approach may predispose patients to higher rates of post-procedure gastroesophageal reflux disease (GERD), mucosal injuries, and CO₂-related insufflation events due to more extensive dissection.

Recent physiologic data from FLIP studies suggest that disrupting the esophagogastric junction (EGJ) complex alone-approximately 2 cm proximally and 2-3 cm distally-may be sufficient to normalize EGJ distensibility in achalasia. Additional proximal myotomy does not appear to improve compliance and may unnecessarily increase the risk of adverse events or compromise esophageal motor recovery. Emerging randomized studies have further shown that shorter esophageal myotomies (≤5 cm) can provide symptom relief comparable to standard approaches, with potentially lower reflux rates.

This trial evaluates whether limiting myotomy to the EGJ complex, with or without a shorter submucosal tunnel, can reduce post-POEM GERD while maintaining clinical efficacy in Type II achalasia. The study uses a three-arm randomized controlled design comparing:

Conventional POEM with long submucosal tunnel and long esophageal myotomy;

Standard-length tunnel with EGJ-only myotomy, preserving proximal esophageal muscle while maintaining full tunnel access;