Objective GERD following POEM significantly increased by length of myotomy

Gastroesophageal reflux disease (GERD) is a known potential sequelae of per oral endoscopic myotomy (POEM) for achalasia. Though the incidence is well documented, the risk factors are far from settled. We aimed to identify predictors of objective post-POEM GERD using endoscopic incidence of esophagitis and wireless pH testing with attention to myotomy length and intraoperative endoluminal functional lumen imaging probe (EndoFLIP) use.

We evaluated 193 patients undergoing POEM at our institution between March 2017 and December 2024. Patients who underwent upper endoscopy (EGD) and/or wireless pH testing at least 6 months post-POEM were included (n = 98). A DeMeester score > 14.72 or documented esophagitis defined objective GERD. Multivariable logistic regression analysis investigated adjusted effects of myotomy length on the incidence of post-POEM GERD. Sensitivity analyses evaluated achalasia- and EndoFLIP-stratified subgroups and addressed potential learning curve effects. Cut-point analysis identified an optimal myotomy threshold.

Of 98 eligible patients (50% female, mean age 52.6 years), 47 (48%) met criteria for objective post-POEM GERD; 14% had erosive esophagitis, while 32% had a positive pH Bravo study without endoscopic esophagitis. Multivariable analysis identified myotomy length as a significant adjusted predictor of post-POEM GERD (OR 1.84, 95% CI 1.17-2.89, p = 0.009). This association was robust when restricted to achalasia patients (OR 1.98, p = 0.024) and when procedure number was included to account for learning curve (OR 1.71, p = 0.017). Cut-point analysis identified 6.5 cm an optimal myotomy length, with better discrimination in the FLIP-measured subgroup (Youden index 0.316 vs. 0.109).

Objective post-POEM GERD occurred in 48% of patients. Myotomy length was an adjusted predictor of post-operative reflux with an optimal threshold of 6.5 cm. The association between myotomy length and GERD risk was most pronounced when undergoing intraoperative EndoFLIP-guided myotomy, suggesting that myotomy length is a modifiable risk factor most clinically actionable in the setting of real-time distensibility monitoring.