IntroductionEsophagogastric junction outflow obstruction (EGJOO) is an esophageal motility disorder characterized by failure of lower esophageal sphincter (LES) relaxation with preserved peristalsis. Studies have shown that Heller myotomy with Dor fundoplication (HMD) and per oral endoscopic myotomy (POEM) are effective treatments for EGJOO. However, there is paucity of data comparing the efficacy and impact of these two procedures. Therefore, the aim of this study was to compare outcomes and impact on esophageal physiology in patients undergoing HMD or POEM for primary EGJOO. MethodsThis was a retrospective review of patients who underwent either HMD or POEM for primary EGJOO at our institution between 2013 and 2021. Favorable outcome was defined as an Eckardt score ≤ 3 at 1 year after surgery. GERD–HRQL questionnaire, endoscopy, pH monitoring, and high-resolution manometry (HRM) results at baseline and 1 year after surgery were compared pre- and post-surgery and between groups. Objective GERD was defined as DeMeester score > 14.7 or LA grade C/D esophagitis. ResultsThe final study population consisted of 52 patients who underwent HMD (n = 35) or POEM (n = 17) for EGJOO. At a mean (SD) follow-up of 24.6 (15.3) months, favorable outcome was achieved by 30 (85.7%) patients after HMD and 14 (82.4%) after POEM (p = 0.753). After HMD, there was a decrease GERD-HRQL total score (31 (22–45) to 4 (0–19); p < 0.001), and objective reflux (54.2 to 25.9%; p = 0.033). On manometry, there was a decrease in LES resting pressure (48 (34–59) to 13 (8–17); p < 0.001) and IRP (22 (17–28) to 8 (3–11); p < 0.001), but esophageal body characteristics did not change (p > 0.05). Incomplete bolus clearance improved (70% (10–90) to 10% (0–40); p = 0.010). After POEM, there was no change in the GERD-HRQL total score (p = 0.854), but objective reflux significantly increased (0 to 62%; p < 0.001). On manometry, there was a decrease in LES resting pressure (43 (30–68) to 31 (5–34); p = 0.042) and IRP (23 (18–33) to 12 (10–32); p = 0.048), DCI (1920 (1600–5500) to 0 (0–814); p = 0.035), with increased failed swallows (0% (0–30) to 100% (10–100); p = 0.032). Bolus clearance did not improve (p = 0.539). Compared to HMD, POEM had a longer esophageal myotomy length (11 (7–15)-vs-5 (5–6); p = 0.001), more objective reflux (p = 0.041), lower DCI (0 (0–814)-vs-1695 (929–3101); p = 0.004), and intact swallows (90 (70–100)-vs-0 (0–40); p = 0.006), but more failed swallows (100 (10–100); p = 0.018) and incomplete bolus clearance (90 (90–100)-vs-10 (0–40); p = 0.004). ConclusionPeroral endoscopic myotomy and Heller myotomy with Dor fundoplication are equally effective at relieving EGJOO symptoms. However, POEM causes worse reflux and near complete loss of esophageal body function. Graphical Abstract [Display omitted]