Post written by Hao Dang, BSc, and Jurjen J. Boonstra, MD, PhD, from the Department of Gastroenterology and Hepatology, Leiden University Medical Center, Leiden, The Netherlands.

Endoscopic submucosal dissection has allowed the endoscopist to perform en bloc resection of various types of GI neoplasms, including subepithelial tumors (SETs). However, submucosal dissection is not feasible for SETs attached to the muscularis propria; these tumors would require dissection in deeper layers.

We discovered a novel dissection plane in the distal rectum wall between the longitudinal muscle layer and the tunica adventitia. Similar to the submucosa, this subadventitial space consists of loose connective fibers. In this video, we demonstrate that dissection in this layer, referred to as endoscopic adventitial dissection (EAD), is feasible and can be used to perform local resection of a rectal GI stromal cell tumor.

It is important to be aware of the different dissection planes in the rectal wall that can be used for local endoscopic resection. We found that adventitial dissection can be performed without damaging the integrity of the tunica adventitia, the deepest layer of the rectal wall. This might open the door for further developments in “fourth-space” endoscopy.

In our article, we provide a step-by-step explanation of EAD. We also pay special attention to the different layers of the rectal wall during the resection. This makes the video useful not only for endoscopists who want to perform EAD, but also those who wish to learn more about the rectal wall anatomy and endoscopic appearances of the different layers.

A, White-light, B, magnetic resonance, and C, EUS images of the tumor.

Read the full article online.

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