By using this technique, resection of the rectum may be extended into the anal canal by removing the internal sphincter completely or partially (‘intersphincteric resec­tion’), thus offering the opportunity for sphincter-preserving resections of tumours below 5 cm from the dentate line.

In general, ultralow resection of rectal cancer with coloanal anastomosis is associated with an acceptable post­operative morbidity and oncological results in the literature. Mortality in most series is below 10%, and the most common complications are urinary and sexual problems (comparable with those associated with APR). Interestingly, clinically relevant insufficiency of the coloanal anastomosis seems to be a rare problem, and pelvic sepsis is observed in larger series in less than 10% of cases. The explana­tions for this finding are mainly speculative and include the high experience in rectal surgery of most of the authors, the use of a protective stoma in most series or the (extraperito- neally performed) anastomosis outside the abdomen in the anal canal.

It is widely accepted that oncological results achieved with ultralow resection of rectal cancer are acceptable and that the local recurrence rate is in the range of 10%. How­ever, there are still candidates for APR. In a series of 134 patients treated by ultralow resection and coloanal anasto­mosis at the Memorial Sloan-Kattering Cancer Center, the following parameters correlated with a high risk for local re­currence: tumour size, perineural or vascular invasion of tumour cells, high histological grade (G III), carcinomatosis of the mesentery and tumour invasion of the resection mar­gins. Therefore, patients having tumours with infiltration of the external anal sphincter as well as of the Musculus levator ani, or with a high grade malignancy close to the anus cer­tainly need APR.

However, sphincter removal does not necessarily mean that the patient has to live with a permanent colostomy. A new technique, dynamic graciloplasty, allows replacement of the anal sphincter by a transposition of the gracilis muscle from the leg as a ‘neosphincter’.

Knowledge of the effects of controlled, chronic, low fre­quency stimulation of the skeletal muscles has led to the ‘revival’ of a procedure reported by Pickrell in 1952. Electrostimulation of the transposed gracilis muscle by an implanted pulse generator causes transformation of fast- twitching type II muscle fibres to slow-twitching (and fatigue-resistant) type I fibres. Following a conversion (training) period of four to eight weeks, the gracilis muscle is able to contract continuously (tetanic contraction) for 24 h. The electronic stimulator can be controlled by the patient with a remote control so that the muscle can be relaxed for defecation.

How is bowel function after sphincter salvage or replace­ment? In general, continence function is reported to be fairly good, even after extensive rectal resection and ultralow or coloanal anastomosis.

Major problems are the loss of the reservoir function of the rectum causing high stool frequencies, fragmentation and other problems. Encouraging results of the use of re­storative (mainly J-) colon pouches to obviate these prob­lems have been reported. Although two randomized trials have reported a superiority of colonic pouches over the straight coloanal anastomosis, it is widely accepted that these benefits are mainly evident during the first two postop­erative months and that approximately 75% of patients with straight coloanal anastomosis improve considerably during the first postoperative year. However, a subgroup of patients (approximately 10%) with colonic pouches complain of se­vere defecation problems, including fecal impactions and evacuation disorders, and require irrigation or enemas permanently.
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Category: Cancer / Tags: Intersphincteric resection, Rectal cancer

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