Mucosal injury (MI) is one of the most common perioperative adverse events of per-oral endoscopic myotomy (POEM). Severe undertreated MI may lead to contamination of the tunnel and even mediastinitis. This study explored the characteristics, predictors, and management approaches of intraoperative MI.

A retrospective review of the prospectively collected database at a large tertiary referral endoscopy unit was conducted for all patients undergoing POEM between August 2010 and March 2016. MI was graded according to the difficulty of repair (I, easy to repair; II, difficult to repair). The primary outcomes were the incidence and predictors of intraoperative MI. Secondary outcomes were MI details and the corresponding treatment.

POEM was successfully performed in 1912 patients. A total of 338 patients experienced 387 MIs, for an overall frequency of 17.7% (338/1912). Type II MI was rare, with a frequency of 1.7% (39/1912). Major adverse events were more common in patients with MI than in those without MI (6.2% vs 2.5%, P < .001). On multivariable analysis, MI was independently associated with previous Heller myotomy (odds ratio [OR], 2.094; P = .026), previous POEM (OR, 2.441; P = .033), submucosal fibrosis (OR, 4.530; P < .001), mucosal edema (OR, 1.834; P = .001), and tunnel length ≥13 cm (OR, 2.699; P < .001). Previous POEM (OR, 5.005; P = .030) and submucosal fibrosis (OR, 12.074; P < .001) were significant predictors of type II MI. POEM experience >1 year was a protective factor for MI (OR, .614; P = .042) and type II MI (OR, .297; P = .042).

MI during POEM is common, but type II injury is rare. Previous POEM and submucosal fibrosis were significant predictors of type II mucosal injury. POEM experience after the learning curve reduces the risk of MI.