Plate 71

The two lateral dissections in the TME are time-consuming, as the surgeon carefully proceeds to expose the parietal fascia over the lateral pelvic wall structures. The fiberoptic lighted deep pelvic retractors are essential for clear visualization during lateral retraction of the rectum and anterior elevation of the bladder or the uterus and vagina. Better lighting may also be obtained with the use of a headlamp. The preservation of the pelvic autonomic nerve plexus and the anterior roots of sacral nerves S2, S3, and S4 is essential for anal continence and sexual function. The plexus is seen as a dense plaque of nerve tissue that comes close to the rectum at the level of the prostate or upper vagina. The TME does not encounter “lateral suspensory ligaments” but rather a fusion of the lateral mesorectum with tissue that may contain the middle hemorrhoidal arteries as the dissection heads toward the autonomic nerve plexus. This tissue is divided with electrocautery, and the middle hemorrhoidal vessels may require a ligature. The course of the ureters and the autonomic plexus is noted as the dissection is carried down to the levators (Figure 10).

After the rectum is transected, the specimen should have a wide zone of relatively smooth fat about the middle and upper rectum. In a thin patient, the pelvic nerves and autonomic nerve plexuses may just be visible beneath the parietal fascia, whereas the prostate and seminal vesicles are uncovered.

After it has been determined that the rectal tumor can be completely freed from the adjacent structures, the blood supply to the rectosigmoid is divided. The venous drainage should be ligated as early as possible to keep the vascular spread of tumor cells to a minimum. Although involved lymph nodes may not be evident in the mesentery over the bifurcation of the aorta, it is desirable to ligate the inferior mesenteric artery just distal to the origin of the left colic artery (Figure 11). The contents of the proximal clamps are tied, and the ligation is reinforced by a transfixing suture. Some prefer to ligate the inferior mesenteric artery as near its point of origin from the aorta as possible. Usually, this level is surprisingly near the ligament of Treitz. The blood supply to the sigmoid to be used as a colostomy is now derived from the middle artery through the marginal artery of Drummond.

Following this, the abdominal cavity and pelvis are completely walled off with gauze as a preliminary to transection with a stapling instrument that divides the bowel between double rows of staples such as a cutting linear stapler (GIA) (Figure 12). The bowel must be divided at a point sufficiently low to provide adequate room for it to be tucked down into the hollow of the sacrum and to permit subsequent closure of the pelvic peritoneum. The sigmoid is covered with a warm, moist gauze pack and reflected upward.

Following this, the closed end of the bowel is covered with a rubber glove or gauze sponge, which is secured in position by an encircling heavy silk suture (Figure 13). The distal segment of bowel is then tucked down into the hollow of the sacrum as a preliminary to the construction of a new pelvic floor (Figure 14).

The redundant sigmoid, which has been retracted upward over the abdominal wall, is inspected to determine the best site (Figure 11, A–A′) for dividing the bowel to serve as a permanent colostomy. The sigmoid is divided where it appears to be viable and will extend beyond the surface of the skin for 5 to 8 cm without being under undue tension. It is better to err in having extra colon beyond the skin margin rather than too little. Consideration must be given to the thickness of the subcutaneous tissues as well as postoperative distention in testing the length of colon mobilized for the permanent colostomy. The proximal end of the specimen is then divided at this point with a cutting linear stapler (GIA). Excessive fat tabs and thick fatty mesentery, if present, should be excised about the terminal end of the colon in anticipation of inversion of the mucosa with immediate fixation to the adjacent skin.

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