A rectum amputation, or abdomino perineal resection (APR), is performed when tumor is situated so low that the sphincter muscle or pelvic floor is infiltrated. In a rectum amputation, the rectum, as well as the anal canal and some of the pelvic floor muscles are removed. The sigmoideum is then used to make a stoma.
If the distance to the tumor is short, an extended rectum amputation (also called a cylindrical rectum amputation) is performed. More of the pelvic floor is removed for this procedure. The defect in the pelvic floor or perianal skin must often be reconstructed with a net or swing flap consisting of muscle and skin. At the Radium Hospital, this is done in collaboration with a plastic surgeon.
There is a higher frequency of local recurrence after a rectum amputation than a after a low anterior resection. The cause of this is somewhat unclear. In the lower part of the rectum, it is very narrow or there is no mesorectal fat. The tumor will therefore quickly infiltrate the pelvic floor muscle if infiltrating the rectal wall. If the infiltration is not macroscopic, this dissection can easily occur in the layer between the rectum and pelvic floor. The tumor may then be perforated and cancer cells released. By stopping the resection toward the pelvic floor from the abdomen earlier, this can be avoided. A cylindrical dissection must be performed in all cases for large, low tumors (T3/T4).
Previously, rectum amputations were performed on 50-60% of rectal cancer cases. After introduction of the total mesorectal resection (TME), the frequency has been reduced to 20-30%. At some foreign treatment centers, about 90% are anastomosized. The percentage depends on how many are irradiated before surgery and whether the most advanced tumors are treated at the hospital or not. It is somewhat unclear how many patients have stool incontinence after very low surgery. Many surgeons therefore prefer a rectum amputation or Hartmann's operation if anal function is reduced.
During the reconstruction phase of the operation, the stoma is made.
- Localized rectal cancer.
- Tumor situated very low and infiltrating the pelvic floor muscle such that the pelvic floor muscle must be removed.
- Palliation in patients with relatively long expected survival time despite distant metastases.