Comparison of 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;

Ultra-short tunnel POEM with EGJ-only myotomy, minimising dissection length and procedure time.

All procedures follow standardized POEM steps, including mucosal entry, submucosal tunneling, myotomy, and mucosal closure. Technical variations between arms are restricted to tunnel length and myotomy extent. Myotomy is performed primarily on the posterior axis, with selective circular myotomy proximally and full-thickness division across the LES as clinically appropriate. Adequacy of gastric extension is confirmed visually, and all mucosal incisions are closed using through-the-scope clips. Intraoperative quality control measures include frequent mucosal inspection, careful dissection along the muscularis propria, and standard management of bleeding or capnoperitoneum.

Participants are randomized in a 1:1:1 ratio using concealed allocation. Blinding of operators is not feasible, but outcome assessors, data collectors, and statisticians remain blinded to minimize detection and assessment bias. Post-procedure evaluation includes symptomatic scoring, endoscopy, manometry when applicable, and 24-hour pH impedance testing. GERD will be assessed both physiologically and via validated patient-reported measures. Adverse events will be systematically recorded using the AGREE classification.

An independent Data and Safety Monitoring Board will conduct an interim analysis after 50% of participants complete 3-month follow-up, with pre-specified stopping rules for superiority, futility, or harm. The large sample size and three-arm design are intended to allow detection of clinically meaningful differences in GERD incidence while ensuring the trial remains adequately powered after accounting for anticipated non-compliance.

This study aims to provide high-quality, comparative data on whether submucosal tunnel length and targeted myotomy at the EGJ can optimize outcomes for Type II achalasia. If shorter techniques demonstrate equivalent clinical success with lower GERD rates and fewer adverse events, they may represent a safer and more efficient modification of the standard POEM procedure.

• Eckardt symptom score [Срок оценки: At 12 weeks and 52 weeks post-procedure]
• Total procedure time [Срок оценки: Periprocedural (during the procedure)]
• use of acid suppressants [Срок оценки: Up to 1 year post-procedure]
• severity of esophagitis [Срок оценки: At 12 weeks post procedure]
• intraoperative and post operative adverse events [Срок оценки: Periprocedural and post-procedure]
• Gastroesophageal Reflux Disease- Health Related Quality of Life questionnaire (GERD-HRQL) [Срок оценки: At 12 weeks and 52 weeks post-procedure]
• Clinically relevant Gastroesophageal Reflux Disease Questionnaire (GERD-Q) [Срок оценки: At 1 year post-procedure]
• duration of hospital stay [Срок оценки: up to 1 week]
• 36-Item Short Form Survey (SF-36) [Срок оценки: At baseline (pre-procedure), 12 weeks, and 52 weeks post-procedure]