Association of gastric myotomy length in peroral endoscopic myotomy (POEM) with gastro-esophageal junction distensibility measured by Endoluminal Functional Lumen Imaging Probe (EndoFLIP).

Background: Endoluminal Functional Lumen Imaging Probe (EndoFLIP) is a device that measures gastro-esophageal junction (GEJ) distensibility. However, it is not demonstrated that GEJ distensibility increases proportionally with varying gastric myotomy length in peroral endoscopic myotomy (POEM). This study aimed to investigate the association between gastric myotomy length in POEM and intraoperative EndoFLIP findings.

Methods: This single-center, retrospective cohort study included patients who underwent POEM with intraoperative EndoFLIP from December 2019 to January 2023. Using EndoFLIP, minimal balloon diameter and its distensibility index (DI) were measured pre- and post-myotomy. Primary and secondary outcomes were the post-myotomy EndoFLIP findings at 30 ml and 40 ml volume fills.

Results: The study included 44 patients (mean age 53.1 years, 50% female). Chicago classification included achalasia type I (39%), II (41%), III (9%), hypercontractile esophagus (2%), and EGJOO (9%). The mean esophageal myotomy length was 7.5 ± 2.2 cm and gastric myotomy was 2.1 ± 0.6 cm. Simple linear regression analyses indicated that for each 1 cm increase in gastric myotomy length, the DI at 30 ml volume fill was estimated to increase by 2.0 mm²/mmHg (p < 0.05, R² = 0.41), the minimal diameter at 30 ml volume fill was estimated to increase by 2.4 mm (p < 0.05, R² = 0.48), and the minimal diameter at 40 ml volume fill was estimated to increase by 1.3 mm (p < 0.05, R² = 0.09).

Conclusions: This study demonstrates a significant linear relationship between gastric myotomy length and GEJ distensibility measured by EndoFLIP during POEM. These findings may be useful in clinical practice by enabling EndoFLIP to help calibrate a desired gastric myotomy length to achieve optimal DI and minimal diameter.