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.

Inclusion Criteria:

• Age ≥ 18 years
• Diagnosis of achalasia or other spastic esophageal motility disorders with an indication for POEM
• ASA physical status I-III
• Ability to provide informed consent

Exclusion Criteria:

• Prior myotomy or major esophageal surgery
• Uncorrectable coagulopathy
• Pregnancy
• Active systemic infection
• Contraindication to anesthesia
• Any situation predicting technical inability to perform POEM

Operator blinding is not feasible due to the nature of the techniques. Participants will remain masked. The primary outcome time will be extracted objectively using automatic timestamps/logs and assessed by masked evaluators; statistical analyses will be performed using masked group labels (A/B). Individual unmasking will be limited to clinical circumstances requiring it.