Technical tips for intersphincteric resection: how to take out the rectum.

Intersphincteric resection (ISR) is an ideal technique that preserves the anus, regardless of whether the internal anal sphincter is removed. However, it is difficult to dissect the anterior wall of the rectum from the adjacent organs. We herein describe a safe and useful ISR technique which draws out the rectum through the anus. The intersphincteric space (ISS) between the internal and external anal sphincter muscles was first transabdominally dissected. Next, the transanal dissection was advanced into the ISS bilaterally from the posterior side without dissecting the anterior wall of the anal canal, and the sigmoid colon and rectum were drawn out through the anus. Dissection between the anterior wall of the rectum and prostate/vagina could be easily performed under direct vision. This technique enables the dissection without any risk of a positive surgical margin or unexpected bleeding, and avoids injury to adjacent organs. This technique seems to be a safe and useful dissection technique for approaching the anterior wall of the anal canal.