Unilateral pudendal neuropathy. Impact on outcome of anal sphincter repair

Our purpose was to study the effect of unilateral pudendal neuropathy on the results of anal sphincter repair.

Fifteen female patients who underwent external sphincter repair for fecal incontinence were studied. In all instances, incontinence was the result of obstetric delivery injury. Anal manometry and neurophysiologic investigations to document sphincter defects and pudendal neuropathy were performed in all patients. Sphincter repair was performed using an overlapping suture technique.

All patients had anterior sphincter defects. Seven patients (47 percent) had pudendal neuropathy: six (85 percent) had unilateral neuropathy, and one (15 percent) had bilateral neuropathy. Six patients (40 percent) had excellent results; three (20 percent) had good results; four (27 percent) were improved; two (13 percent) experienced no improvement after sphincter repair. All patients with excellent results had normal pudendal nerve terminal motor latency on both sides. Of the three patients with good results, one patient had unilateral pudendal neuropathy. The patients in the remaining two groups (improved and failed) had unilateral (six patients) or bilateral (one patient) pudendal neuropathy.

We conclude that both pudendal nerves must be intact to achieve normal continence after sphincter repair. Patients with unilateral pudendal neuropathy are more likely to have poor than to have good postoperative function.