PubMed1996
Despite the tendency toward sphincter-saving surgical procedures, a small proportion of rectal cancers must still be treated by abdominoperineal resection (APR). The physical, psychological and social consequences of a permanent abdominal stoma are a challenge to perform a continent perineal colostomy. Most of the attempts originate from experiences with gracilis muscle transposition in the treatment of fecal incontinence, in particular Pickrell's operation. Functional results are however conditioned by the fact that the transposed muscle takes up a different function and its natural evolution, if not adequately stimulated, consists of atrophy and fibrosis. The most important series of graciloplasty in APR is reported by Cavina and coworkers (75 cases from 1985 to 1993), who at first obtained good functional results by external electromyostimulation (EMS) and biofeedback, then registered a further improvement using internal, continuous low-frequency EMS by implantable pulse generators (IPG). The surgical technique involves, after APR: bilateral dissection of the gracilis up to the proximal neurovascular pedicle and detachment of the distal tendon; mobilization of the muscles, through the subcutaneous tissue, into the perineum, where the colonic stump is drawn out; positioning the right gracilis behind the colonic stump, as a puborectalis sling, and the left gracilis around it, in a sort of "alpha" configuration; suturing the colonic stump to the perineal skin; optionally, temporary diverting loop colostomy. The operation is completed by the insertion of two electrodes near the nerve, for external or internal EMS (in the last case: implantation of IPG). The external EMS may be carried out by current cardiac temporary electrodes, drawn up through the skin of the iliac area. It is aimed at preserving the trophism and the contractility of the muscle and enabling the patient to learn a new function of continence (actually, it is a "pseudocontinence"), thanks to a program of intermittent stimulation and biofeedback. Electrodes and other devices are not expensive. The internal EMS requires specific electrodes, connected to an IPG, implanted in a subcutaneous abdominal pocket. The continuous stimulation gives rise to a tonic activity of the gracilis, resulting in higher resting anal pressure and "true" continence. The IPG is programmed under telemetry control, step by step until the most suitable EMS parameters are reached. A magnet allows the patient to turn the IPG "off" of "on", according to the necessity to void the bowel. A complete set of 1 IPG and 2 electrodes costs about $10,000. Cavina reports good continence in 71% of the cases treated by external EMS and 100% of the patients with IPG. Our first graciloplasty in APR was performed in April 1994. Since then we have carried out 6 operations. Because of its high cost, we decided that, at least at a first phase, the IPG should be implanted, from the 7th month on, only in disease-free patients, when functional results suggested a possible clinical improvement. Until today, 3 patients have had the abdominal stoma closed and can be evaluated from a functional viewpoint. We recorded 1 "excellent" and 2 "fair" results. In the two patients with a "fair" result we implanted a pulse generator about a month after the closure of the abdominal colostomy. A good manometric and clinical improvement was registered. The patient with "excellent" functional result had a recurrence one month after the closure of the stoma. Though limited, our experience is absolutely favourable as to graciloplasty, but an evaluation from us whether external or internal EMS is better, is too early at the moment. In absolute functional terms, the internal, continuous EMS is preferable, but problems of cost and oncologic prognosis restrict the use of IPG.