Blown-out myotomy: an adverse event of laparoscopic Heller myotomy and peroral endoscopic myotomy for achalasia

Background and Aims: Although laparoscopic Heller myotomy (LHM) or peroral endoscopic myotomy (POEM) is highly effective, 10% to 20% of patients with achalasia remain symptomatic after treatment. In evaluating such patients, we have observed a pattern of failure associated with a pseudodiverticulum, or blown-out myotomy (BOM), in the distal esophagus. We aimed to assess risk factors and patient-reported outcomes associated with a BOM.Methods: We reviewed our manometry database for patients with achalasia previously treated with LHM or POEM. We included patients who had a post-treatment esophagram within 1 year of their follow-up manometry. A BOM was defined radiographically as a wide-mouthed outpouching (>50% increase in esophageal diameter) in the area of the myotomy.Results: One hundred twenty-nine patients with achalasia who underwent treatment were included; 23 (17.8%) had a BOM. Comparing patients with a BOM with those without, post-treatment Eckardt scores were significantly greater (5 vs 2, P = 002), type III achalasia was more common (39.1% vs 14.2%, P = 005), and LHM was more common than POEM (73.9% vs 26.1%, P = 013). The integrated relaxation pressure was also significantly greater in the BOM group (15.0 mm Hg vs 11.0 mm Hg, P = 025).Conclusions: BOM is a common adverse event after myotomy for achalasia but is not seen after pneumatic dilation. Pretreatment type III achalasia, LHM as opposed to POEM, and a greater post-treatment integrated relaxation pressure were risk factors for developing a BOM. We speculate that esophageal wall strain in the area weakened by myotomy, whether from residual spastic contractility or continued esophageal outflow obstruction, may be the underlying mechanism of BOM development.