Analysis of a Learning Curve and Predictors of Intraoperative Difficulty for Peroral Esophageal Myotomy (POEM)

Background: Peroral esophageal myotomy (POEM) is an endoscopic surgical operation for achalasia. Here, we analyze a single-series POEM learning curve and examine which preoperative patient factors are predictive of operative difficulty. Methods: Two surgeons performed all POEM procedures conjointly. Nonlinear regression was used to determine the learning curve for procedure time. Preoperative patient characteristics were correlated with outcomes. Results: Thirty-six POEM procedures were performed. Total operative time did not decrease over the course of the series (mean 112 ± 36 min). Time required to complete the procedural steps of submucosal access and myotomy did decrease with experience, both exhibiting a "learning rate" of seven cases. The incidence of inadvertent mucosal perforations and the number of clips required both decreased with experience. Postoperative Eckardt scores at 1-year follow-up decreased over the course of the series. Prior endoscopic treatment, symptom duration, and esophageal width were all independently predictive of longer procedure time. Preoperative symptom duration was also positively associated with inadvertent mucosal perforation and the number of clips required. Conclusions: In this series, overall procedure time did not decrease with experience and may not be an important marker of procedural skill for POEM. Prior endoscopic treatment, longer symptom duration, and esophageal dilatation may result in increased operative difficulty during POEM.