Clin Endosc.  2023 Jan;56(1):23-37. 10.5946/ce.2022.139.

Submucosal endoscopy: the present and future

• Nabi Z
• Reddy DN

• KMID: 2538748
• DOI: http://doi.org/10.5946/ce.2022.139

Abstract

Submucosal endoscopy or third-space endoscopy utilizes the potential space between the mucosal and muscularis layers of the gastrointestinal tract to execute therapeutic interventions for various diseases. Over the last decade, endoscopic access to the submucosal space has revolutionized the field of therapeutic endoscopy. Submucosal endoscopy was originally used to perform endoscopic myotomy in patients with achalasia cardia, and its use has grown exponentially since. Currently, submucosal endoscopy is widely used to resect subepithelial tumors and to manage refractory gastroparesis and Zenker’s diverticulum. While the utility of submucosal endoscopy has stood the test of time in esophageal motility disorders and subepithelial tumors, its durability remains to be established in conditions such as Zenker’s diverticulum and refractory gastroparesis. Other emerging indications for submucosal endoscopy include esophageal epiphrenic diverticulum, Hirschsprung’s disease, and esophageal strictures not amenable to conventional endoscopic treatment. The potential of submucosal endoscopy to provide easy and safe access to the mediastinum and peritoneal spaces may open doors to novel indications and rejuvenate the interest of endoscopists in natural orifice transluminal endoscopic surgery in the future. This review focuses on the current spectrum, recent updates, and future direction of submucosal endoscopy in the gastrointestinal tract.

Keyword

Achalasia; Gastroparesis; Submucosal endoscopy; Zenker’s diverticulum

Figure

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  Fig. 1. Current spectrum of submucosal endoscopy in gastrointestinal tract.

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  Fig. 2. Technique of per-oral endoscopic myotomy in esophageal motility disorders. (A) Submucosal lifting injection using an injection needle. (B) Mucosal incision using a triangular knife. (C) Submucosal tunneling using a triangular knife. (D) Control of intraprocedural bleeding using coagulation forceps. (E) Selective circular (upper part) and full-thickness myotomy. (F) Closure of the mucosal incision with endoclips.

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  Fig. 3. Submucosal tunneling with division of cricopharyngeal septum in a case of Zenker’s diverticulum. (A) Endoscopic image revealing the cricopharyngeal septum. (B) Submucosal lifting injection proximal to the septum. (C) Mucosal incision using an electrosurgical knife. (D) Submucosal tunneling along the diverticulum pouch. (E) Submucosal tunneling along the esophageal side and complete exposure of the septum. (F) Division of the cricopharyngeal septum using an electrosurgical knife. (G) Completion of cricopharyngeal myotomy. (H) Closure of mucosal incision with multiple endoclips.

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  Fig. 4. Gastric per-oral endoscopic myotomy in a case of refractory gastroparesis. (A) Submucosal lifting injection 3 to 4 cm proximal to the pylorus. (B) Submucosal tunneling towards the pylorus. (C) Visualization of the pyloric sphincter. (D) Confirmation of extension of submucosal tunnel beyond the pyloric sphincter. (E) Execution of endoscopic pyloromyotomy. (F) Endoscopic appearance of the pyloric sphincter after pyloromyotomy. Courtesy by Harshal Mandavdhare (Associate Professor, Post Graduate Institute of Medical Education and Research, Chandigarh, India).

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  Fig. 5. Submucosal tunneling endoscopic resection in a case of esophageal subepithelial tumor. (A) Endoscopic appearance of the mid-esophageal subepithelial lesion. (B) Submucosal lifting injection 2 to 3 cm above the subepithelial lesion. (C) Vertical mucosal incision using a triangular knife. (D) Submucosal tunneling along the presumed orientation of the subepithelial lesion. (E) Exposure of the subepithelial tumor. (F) Dissection of the tumor from surrounding attachments. (G) Retrieval of the tumor using a polypectomy snare. (H) Closure of the mucosal incision using endoclips.

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  Fig. 6. Individualized approach to gastric subepithelial. Note the preferred location of gastric submucosal lesions for ESE and STER (from Lu et al. PLoS One 2015;10:e011987077). ESE, endoscopic submucosal excavation; STER, submucosal tunneling endoscopic resection.

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  Fig. 7. Per-rectal endoscopic myotomy in a patient with Hirschsprung’s disease. (A) Submucosal lifting injection. (B) Transverse mucosal incision 1 to 2 cm above the anal verge. (C) Submucosal tunneling with arrows indicating the muscle layer. (D) Completion of submucosal tunneling. (E) Full-thickness myotomy. (F) Closure of the mucosal incision using endoclips. Courtesy by Mohan Ramchandani (Consultant Gastroenterologist, Asian Institute of Gastroenterology, Hyderabad, India).

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