Submucosal endoscopy, a new era of pure natural orifice translumenal endoscopic surgery (NOTES)

Abstract

Natural orifice translumenal endoscopic surgery (NOTES) involves the intentional perforation of the viscera with an endoscope to access the abdominal cavity and perform an intraabdominal operation. In a brief time period, NOTES has been shown to be feasible in laboratory animal and human studies. Easy access to the peritoneal cavity and complete gastric closure should be secured before NOTES can be recommended as an acceptable alternative in clinical practice. The concept of submucosal endoscopy has been introduced as a solution to overcome these two primary barriers to human NOTES application. Its offset entry/exit access method effectively prevents contamination and allows the rapid closure of the entry site with a simple mucosal apposition. In addition, it could be used as an endoscopic working space for various submucosal conditions. Herein, the detailed procedures, laboratory results and human application of the submucosal endoscopy will be reviewed.

Keywords: Endoscopy; Natural orifice; Submucosal.

Fig. 1

Schematic drawings of submucosal endoscopy with mucosal flap technique. (A) The submucosal plane is isolated with injection of CO₂ gas injection, (B) repeated balloon dissection of the submucosa. (C) The endoscope is inserted into the submucosal space, a myotomy exit site is made with modified cap EMR technique. (D) The peritoneal cavity is accessed via the myotomy. (E) The endoscopic entry point into the submucosal space is closed (Adopted from Sumiyama et al. Minim Invasive Ther Allied Technol 2008;17:365-369).

Fig. 2

Schematic drawings of modified endoscopic submucosal dissection (ESD) technique. (A) Submucosal injection with normal saline solution. (B) Creation of a longitudinal narrow submucosal tunnel using ESD. (C) Advancement of an endoscope into the peritoneal cavity. (D) Closure of the mucosal incision site using endoclips (Adopted from Yoshizumi et al. Endoscopy 2009;41:707-711).

Fig. 3

Peroral transgastric peritoneoscopy. (A) A mucosal incision at the submucosal bleb. (B) A submucosal tunnel created using endoscopic submucosal dissection. (C) Balloon dilation after a small puncture of the seromuscular layer. (D) Endoscopic forceps biopsy from the metastatic nodules in the peritoneum.

Fig. 4

Endoscopic full-thickness resection of subepitherial tumor (SET). (A) A SET at the anterior wall of the low body. (B) A submucosal tunnel created using endoscopic submucosal dissection. (C) The exposed tumor within the submucosal tunnel. (D) Full-thickness incision around the tumor. (E) Full-thickness dissection of the seromuscular layer. (F) The final snare resection of the tumor.

Fig. 5

Peroral endoscopic myotomy. (A) Entry to submucosal space. (B) Submucosal tunneling. (C) Endoscopic myotomy, with a total length of 10 cm. (D) Long endoscopic myotomy of inner circular muscle bundles, leaving the outer longitudinal muscle layer intact. (E) Closure of mucosal entry (Adopted from Inoue et al. Endoscopy 2010;42:265-271).