Pudendal neuropathy in evacuatory disorders

Aims of the present study were to assess frequency of pudendal neuropathy in patients with constipation and fecal incontinence, to determine its correlation with clinical variables, anal electromyographic assessment, and anal manometric pressures, and to determine usefulness of the pudendal nerve terminal motor latency assessment in evaluation of these evacuatory disorders.

From 1988 to 1993, 395 patients (constipated, 172; incontinent, 223) underwent pudendal nerve terminal motor latency, electromyography, and anal manometry. Pudendal neuropathy was defined as a pudendal nerve terminal motor latency greater than 2.2 ms.

Patients were a mean age of 60.7 (range, 17-88) years. Overall incidence of pudendal neuropathy was 31.4 percent (constipated, 23.8 percent; incontinent, 37.2 percent; P < 0.05). Incidence of pudendal neuropathy dramatically increased after 70 years of age in both groups (22 percent vs. 44 percent; P < 0.05). Moreover, subjects with pudendal neuropathy were older than those without pudendal neuropathy (mean age, 67 vs. 57 years; P < 0.05). The presence of pudendal neuropathy was associated with decreased motor unit potentials recruitment in patients with incontinence (P < 0.01). Patients with and without pudendal neuropathy had a similar mean squeezing pressure in both groups.

Pudendal neuropathy is an age-related phenomenon. Although pudendal neuropathy is associated with abnormal anal electromyographic findings in patients with incontinence, no association with anal manometric pressures was found. Pudendal nerve terminal motor latency assessment is a useful tool in the evaluation of patients with fecal incontinence, but its role in the assessment of constipated patients remains unknown.