Pudendal nerve function in idiopathic fecal incontinence

The study was undertaken to determine whether idiopathic fecal incontinence in middle-aged and elderly females is likely to be a result of pudendal nerve damage (neurogenic incontinence) or merely a consequence of aging.

One hundred seventy-eight females over the age of 50 years with fecal incontinence were studied. The incontinence was classified as idiopathic because none of the patients related the incontinence to trauma (including obstetric trauma) or other events or diseases. All had an anal physiology examination, including determination of nerve conduction velocity of both pudendal nerves (pudendal nerve terminal motor latency).

With a cutoff value of 2.4 msec, 79 percent (95 percent confidence limit, 73-85) had normal pudendal nerve terminal motor latency on both sides, 13 bilaterally prolonged latency (7 percent; 4-11), and 25 unilaterally prolonged latency (14 percent; 9-19). With a cutoff value of 2.2 msec, 66 percent (59-73) had normal latency on both sides, 15 percent (9-20) bilaterally prolonged pudendal nerve terminal motor latency, and 20 percent (14-26) unilateral prolongation. No relationship between the groups with normal, bilateral, or unilateral prolongation of pudendal nerve terminal motor latency and anal resting and squeeze pressure was found. Anal resting pressure decreased with increasing age (P < 0.05).

Our data support the view that idiopathic fecal incontinence in the majority of females is likely to be a result of the aging process and that only a limited number may suffer from anal incontinence of neurogenic origin. Furthermore, unilateral prolongation of pudendal nerve terminal motor latency probably is without clinical significance.