Novel technique “short myotomy” during endoscopic submucosal dissection for a diverticulum-associated colonic lesion

While endoscopic submucosal dissection (ESD) for colorectal tumors is widely accepted,^{1, 2} ESD for tumors involving a diverticulum is still challenging and associated with a high risk of perforation due to the absence of the muscularis propria. Additionally, during the procedure there is a risk of damage to the specimen or interruption of ESD, given an insufficient plane in the submucosal layer within the diverticulum. Therefore, we report the tips of ESD including the novel technique named “short myotomy” for a diverticulum-associated lesion to resolve this problem (Video S1, Fig. 1). The lesion was located on the dorsal side of the ascending colon. A procedure was performed with the patient under conscious sedation and using carbon dioxide insufflation. A small-caliber transparent hood (DH-29CR; Fujifilm, Tokyo, Japan) was attached to the tip of an endoscope, and a 1.5 mm Dual knife (KD650Q; Olympus, Tokyo, Japan) was the surgical device used. After completing the circumferential mucosal incision, a submucosal dissection was made. The water pressure technique was applied for dissecting the submucosa with the multiloop device.^{3, 4} When getting into the diverticulum, the dissection plane was narrow between the muscle layers and the specimen (Fig. 2a). Then, the incision of muscle layers in front of the diverticulum was made to create a dissection plane to go below the diverticulum (Fig. 2b,c). This short myotomy enabled the precise excision below the diverticulum (Fig. 2d). The lesion was resected in one piece without specimen damage. The ulcer bed including the diverticulum was completely closed with endoscopic clips. An abdominal computed tomography scan immediately after ESD showed no extraluminal air. The patient was discharged on postoperative day 3. The histopathological diagnosis indicated intramucosal cancer with negative margins. The short myotomy is a novel technique in addition to existing methods, which allows for secure ESD for complete resection and a time-saving procedure.

Authors declare no conflict of interest for this article.

Approval of the research protocol by an Institutional Reviewer Board: This study was approved by the Ethics Committee of Yokohama City University Medical Center.

Informed Consent: N/A.

Registry and the Registration No. of the study/trial: N/A.

Animal Studies: N/A.