Rectal pacing in patients with constipation due to rectal inertia: technique and results

In a previous study we determined the rectal pacing parameters needed for r ectal evacuation in patients with rectal inertia. Here we investigated the effect of rectal pacing on rectal myoelectric activity, motility, and evacu ation in ten patients with constipation due to rectal inertia. A pacemaker was implanted in a subcutaneous pocket above the inguinal area, with a lead threaded in the anal submucosa to be hooked at the rectosigmoid junction. The effect of rectal pacing on rectal electric activity was investigated by inserting two recording electrodes to the rectal mucosa. The patients were then trained for home pacing. No waves were recorded from the rectum at re st. On rectal pacing, slow waves or pacesetter potentials (mean frequency 2 .3+/-1.1 cpm, amplitude 0.86+/-0.1 mV, velocity 3.4+/-1.6 ms) were register ed after a latency period of 5.2+/-1.6 min. Rectal evacuation, on pacing, o ccurred in seven of the ten patients. The three who showed no significant r esponse exhibited low wave parameters. Three of seven patients were able to evacuate spontaneously without pacing after having performed daily pacing for 5-6 months. The pacemaker was removed in six patients (three failures a nd three after spontaneous defecation). Thus rectal pacing succeeded in ind ucing rectal evacuation in 70% of the patients. The procedure failed in thr ee patients. Three had spontaneous defecation after a few months of rectal pacing. No complications were encountered, and the method was tolerated and acceptable. Further studies on a large group of patients are required.