Prevalence and clinical characteristics of blown-out myotomy after E-POEM for achalasia: a systematic review and meta-analysis

BACKGROUND: Achalasia is a primary esophageal motility disorder characterized by impaired lower esophageal sphincter relaxation and absent peristalsis. Treatment options include Pneumatic Dilation, Laparoscopic Heller Myotomy, and Esophageal Peroral Endoscopic Myotomy (E-POEM). A focal distal esophageal dilation at the myotomy site, termed blown-out myotomy (BOM), has been reported in 9% - 32% of patients and may be associated with reflux, esophageal retention, and treatment failure. The clinical significance of BOM remains unclear. This meta-analysis evaluated the prevalence and clinical characteristics of BOM following E-POEM. METHODS: A systematic search of electronic databases and conference proceedings from inception through November 2025 identified prospective and retrospective studies reporting the prevalence or clinical features of BOM after E-POEM. The primary outcome was pooled BOM prevalence. Secondary outcomes included symptom severity (Eckardt score), myotomy characteristics, and associations with achalasia subtypes. Studies reporting ≤ 3 BOM cases or lacking extractable data were excluded. Pooled proportions were calculated using a fixed-effects model. Publication bias was assessed using the Begg-Mazumdar test. Mean Eckardt scores were compared using an unpaired t-test. RESULTS: Four studies comprising 947 patients were included. The pooled prevalence of BOM was 11.16% (95% CI: 9.28% -13.25%). No evidence of publication bias was detected (Kendall's tau-b = 0.33; p = 0.75). Baseline characteristics were comparable between groups. Mean myotomy length was 10.39 ± 1.82 cm in the BOM group and 11.23 ± 1.46 cm in the non-BOM group. Pretreatment Eckardt scores were similar (6.67 vs 6.63), as were 3-month post-E-POEM scores (2.05 vs 1.93). Pooled odds ratios for BOM were 0.73 (95% CI: 0.47-1.13) for type I achalasia, 0.79 (95% CI: 0.53-1.19) for type II, and 1.38 (95% CI: 0.80-2.38) for type III. CONCLUSIONS: BOM occurs in a minority of patients following E-POEM. Across studies, BOM did not show consistent associations with symptoms or procedural characteristics.