Over the last two decades, major evolutions have occurred in the treatment of rectal cancer. Currently, with advances in rectal anastomosis techniques, sphincter saving procedure has become the standard treatment in the surgical approach to most cancers of the upper, middle, and even lower third of the rectum.
The term “low” anterior resection refers to a colorectal anastomosis performed at between distal to the anterior peritoneal reflection and proximal to the anorectal junction. This is verge, again depending upon the patient’s body build.
The term “ultra-low” or “extended” anterior resection refers to a colorectal or more usually, a coloanal anastomosis at the level of the anorectal junction. This is the type of anastomosis that is performed after proper total mesorectal excision and incision of the Waldeyer’s fascia posterior to the rectum. The latter technical step allows the rectum to be mobilized/“freed” both anteriorly and proximally from the pelvis, allowing for transection of the rectum safely at the anorectal junction.
The level of this anastomosis is normally measured to be about 3-5 cm from the anal verge. Such distal anastomoses have much higher risk of anastomotic dehiscence and consideration should be given to temporary defunctioning by either a colostomy or ileostomy.
The term “intersphincteric dissection” refers to the special situation where a very distal rectal cancer is excised with clear oncological resection margins by including an en-block excision of the internal anal sphincter and anal mucosa, to the level of the dentate (pectinate) line. The last part of the procedure is usually performed transanally. Reconstruction is done by a pullthrough procedure with hand-sewn anastomosis of the colon to the distal anus, again by the transanal route.
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