Dissection of mucosa and muscularis mucosa instead of submucosal dissection: rapid retroflow of the injection fluid can be an indicator.

Prolonged contact of the esophageal mucosa with food in sigmoid achalasia causes mucosal edema and ulcerations that lead to submucosal fibrosis. The mucosal incision was completed with a triangle knife; however, the area reached following the incision was not the submucosa but the space between the mucosa and the muscularis mucosa. [Extracted from the article]