Closure methods for large defects after gastrointestinal endoscopic submucosal dissection.

Nowadays, endoscopic submucosal dissection (ESD) is commonly performed for the removal of large gastrointestinal lesions. Endoscopic mucosal defect closure after ESD is vital to avoid adverse events. In recent years, many innovative instruments have emerged and proved to be beneficial. In this paper, we conducted a thorough literature review and summarized the closure methods for large-size post-ESD mucosal defects over decades. We separated these methods into five categories based on the operational principle: "side closure" method, "ring closure" method, "layered closure" method, "hand suturing closure" method, and "specially designed device closure" method. Side closure with clips assisted by instruments such as threads or loops is applicable for each segment of the gastrointestinal tract to prevent postoperative bleeding. If the defect tension is too large to close with the traditional side closure methods, zigzag closure and ring closure could be applied to gather the bilateral defect edges together and achieve continuous closure. In the stomach and rectum with a high risk of submucosal dead space between the submucosa and muscular layers, side closure methods with muscle layer grasping clip or layered closure methods could enable the involvement of the deep submucosa and muscle layers. The ring closure method and specially designed devices including over-the-scope clip, Overstitch, and X-tack could resolve perforation effectively. Individual closure method requires endoscope reinsertion or sophisticated operation, which may be limited by the deep location and the narrow lumen, respectively. Although specially designed devices are expected to offer promising prospectives, the cost-effectiveness remains to be a problem.