Transverse Versus Longitudinal Mucosal Incision in Peroral Endoscopic Myotomy: A Multicenter Randomized Clinical Trial

Peroral endoscopic myotomy (POEM) is a minimally invasive endoscopic procedure used to treat achalasia and other spastic esophageal motility disorders. A key step in POEM is creating a small opening in the esophageal lining (mucosal incision) to enter the submucosal tunnel. This study evaluates whether making that entry incision **transverse** (across the esophagus) versus **longitudinal** (along the esophagus) improves procedural efficiency without reducing safety.

This is a **multicenter, randomized (1:1), parallel-group clinical trial** conducted in three therapeutic endoscopy units in Colombia (Hospital Universitario del Valle and Clínica Versalles in Cali, and Clínica del Occidente in Bogotá). Adults (≥18 years) with an indication for POEM, ASA I-III, and ability to provide informed consent will be eligible; key exclusions include prior myotomy/major esophageal surgery, uncorrectable coagulopathy, pregnancy, active systemic infection, anesthesia contraindication, or anticipated technical inability to perform POEM.

All procedures are standardized: POEM under **general anesthesia with orotracheal intubation**, **CO₂ insufflation**, validated endoscopic knives and preset electrosurgical modes; hemostasis with **Coagrasper® only if needed**; and closure using standard **through-the-scope (TTS) clips**. Participants are randomly assigned to a **15 mm transverse mucosal incision** (perpendicular to the esophageal axis) or a **15 mm longitudinal mucosal incision**. Full-procedure video is recorded for quality control and to allow objective timing, with blinded assessment of the primary outcome.

The **primary outcome** is the time (seconds) from the first mucosal cut to successful entry of the endoscope cap into the submucosal tunnel (advancing at least 1 cm). **Secondary outcomes** include need for hemostasis with Coagrasper®, number of clips required for complete closure, and early complications (including perforation and gas-related events such as capnoperitoneum requiring decompression and emphysema), monitored through **30 days**.

Participants complete a screening/preoperative visit (up to 30 days before), undergo the POEM procedure, have early in-hospital/discharge assessment (days 1-2), and receive safety follow-up contacts at approximately 1 week and day 30.

Risks are those expected from standard POEM and peri-anesthesia care (e.g., bleeding, perforation, infection, and gas-related complications), and participants may not directly benefit clinically. However, the transverse incision may shorten access and closure time and reduce resource use without increasing short-term complications.

The study will be conducted with written informed consent, confidentiality protections (pseudonymization and secure storage), and reporting of results in aggregate form.