The Colorectal Quiz Episode 4

Extensive transanal dissection causes overstretching of the sphincters, which is a morbidity that needs to be avoided, and laparoscopy helps with that.

The transanal dissection should usually take way under an hour, especially in a primary pull-through.

For a full-thickness biopsy, the seromuscular side should be the same size as the mucosal side when cutting a square cube.

Frozen section must show ganglion cells and nerves that are less than 40 microns; hypertrophied nerves indicate the segment should not be pulled through.

The biopsy must include submucosa because ganglion cells might be found in the seromuscular layer while hypertrophic nerves are in the submucosal layer.

When taking mesenteric vessels, staying just off the bowel rather than deep in the mesentery tends to be less bloody.

In the old Swenson procedure done through the abdomen, patients were non-infrequently incontinent and had urinary retention, believed to be related to too wide a dissection of the distal rectum and injury to the neurogenic plexus.

The arcade along the left colon and sigmoid colon must be preserved to get enough distance to reach the pelvis.

For distal disease, only distal branches of the IMA need to be taken, but for left colon or splenic flexure involvement, the IMA itself might need to be taken.

The transanal dissection should start with a mark about one centimeter above the dentate line into the anal canal.

Dr. Levitt prefers a Swenson full-thickness dissection in the areolar plane, which is basically bloodless, rather than a submucosal dissection because he does not want to leave a cuff.

A five-centimeter margin above the biopsy site is very safe when determining where to transect the bowel.

Tacking sutures on the serosa to the pelvic sidewall at the three and six o'clock positions anchor the bowel in place.