Safety and Efficacy of the Submucosal Tunnel Without Mucosal Closure for the Transgastric Approach in a Porcine Survival Model

Abstract

Introduction. Usefulness of submucosal tunneling for transgastric approach with clip closure of the mucosal incision in natural orifice translumenal endoscopic surgery (NOTES) has been described. Although the narrow longitudinal submucosal tunnel itself is considered good for wound approximation and healing, no reports have evaluated the sealing effect in this technique. This study was aimed at evaluating the technical feasibility of a submucosal tunnel technique for transgastric peritoneal access without mucosal closure. Methods. Transgastric peritoneoscopy using submucosal tunneling with endoscopic submucosal dissection without mucosal closure was performed on six 40- to 45-kg female pigs. Measures included (a) evaluation of technical feasibility, (b) clinical monitoring for 7 days, (c) necropsy findings, and (d) pathological examination. Results. NOTES transgastric peritoneoscopy was successfully performed in all pigs, and all recovered well clinically. Necropsy findings revealed no peritonitis, confirming completeness of gastric closure in 5 of the 6 pigs. One pig in which the submucosal layer of the tunnel was injured during dissection from the muscular layer showed local peritonitis. Pathological examination at the submucosal site tunnel showed wound healing with focal transmural fibrosis and inflammatory cell infiltration in 5 pigs, whereas the pig with peritonitis had a large mucosal defect with necrotic tissue, abscess formation, and focal transmural fibrosis. Conclusions. The submucosal tunnel technique without mucosal closure is safe and effective for transgastric peritoneal access and subsequent closure, when the endoscopists’ learning curve is accomplished and the submucosal tunnel is produced without damaging of mucosa. It is necessary to use devices such as mucosal clips or tissue anchors in order to achieve adequate healing of mucosal defect.