Normal proximal and delayed distal conduction in the pudendal nerves of patients with idiopathic (neurogenic) faecal incontinence.

Abstract

SUMMARY The latency of the response in the external anal sphincter muscle following transcutaneous stimulation of the cauda equina at the Li vertebral level was measured in nine women with neurogenic faecal incontinence (mean 7-3 SD 0-7 ms) and 11 normal subjects (mean 5-6 SD 0-6 ms) (p = 0.01). There was no difference in conduction velocity between the Li and L4 vertebral levels thus supporting the suggestion that conduction delay in faecal incontinence occurs distally.In patients with idiopathic faecal incontinence there is evidence of neurogenic damage to the puborectalis and external anal sphincter muscles.'-3 We have recently demonstrated an increased latency in the response of the external anal sphincter muscle to trans-rectal stimulation of the pudendal nerve at the level of the ischial spine in these patients.4 Marsden, Merton and Morton' measured the latency of the response in this muscle in two normal subjects following transcutaneous spinal stimulation and we have now applied this method to investigate our patients with faecal incontinence.Parks, Swash and Urich suggested in 1977 that because the pudendal nerves are tightly bound by connective tissue on leaving the pelvis and entering the pudendal canal, descent of the pelvic floor during childbirth or defaecation straining might result in stretch injury to these nerves.' Henry, Parks and Swash6 have shown that the amount of descent of the pelvic floor measured in incontinent patients with the descending perineum syndrome would result in a 20% increase in the length of the pudendal nerves-more than sufficient to cause injury.7 We wished to know if the increased latency found on transrectal stimulation of the pudendal nerves in incontinent patients was limited to the distal portion of the pudendal nerves, as would be expected with this entrapment/stretch hypothesis, or whether conAddress for reprint requests: Dr M Swash, The London Hospital, Whitechapel, London El 1BB, UK.Received 1 1 November 1983 and in revised form 17 January 1984. Accepted 30 January 1984 duction was delayed in the whole length of these nerves suggesting a more proximal lesion. Patients and methodsNine women aged 28-71 years (mean 50 9, SD 16-9 years) presenting with neurogenic faecal incontinence were studied, and the results compared with those obtained from 11 normal volunteers or patients attending for follow-up of benign colonic pathology, or minor ano-rectal conditions, aged 18-58 years (mean 42-9, SD 13-2 years). Manometry and EMGThe incontinent patients were all examined by ano-rectal manometry using methods previously standardised in our laboratory.

Sacral spinal cord and root potentials evoked by the stimulation of the dorsal nerve of penis and cord conduction delay for the bulbocavernosus reflex

“…levels were significantly longer than those reported for external anal sphincter and BC muscle in other studies [Kiff and Swash 1984;Snooks and Swash, 1984Swash and Snook, 1986;Vodusek and Zidar, 1988;Opsomer et al, 19891. This difference is partly due to the different points of stimulation, i.e., the lower sacral roots and/or sacral cord were stimulated within the epidural space in our bipolar epidural stimulation technique while in other studies the sacral roots and/or nerves must have been stimulated electrically or mag- netically at or apart from their exit from the vertebral canal on the skin surface [Mills and Murray, 19861.…”

Pudendal Canal Decompression in the Treatment of Idiopathic Fecal Incontinence

“…Pudendal Nerve Terminal Motor Latency PNTML was measured on both sides [10]. The test was repeated at least three times to assure reproducibility.…”

Current Techniques of Assessing Defecation Dynamics

“…The time interval between the stimulus artifact and the onset of myoelectrical response is measured as the nerve motor latency time [5], Normal latency is 2.2 ms [5], A prolonged nerve latency is suggestive of pudendal neuropathy. This may occur follow ing obstetric trauma [5,42] and occasionally following surgical trauma and has also been reported in patients with idiopathic fecal in continence [51]. It has been postulated that excessive perineal descent, over many years, may lead to pudendal neuropathy and cause fecal incontinence [5].…”

“…This quantifies the electrical activity of the EAS or puborectalis [51,52] and measures the amplitude, the motor unit action potentials and facilitates interpretation of the pressure recordings between the EAS and IAS [15,53], Overall, it provides information about nerve innervation and the functional state of indi vidual motor units. The techniques used to record electromyography activity include bi polar wire electrodes, surface electrodes, monopolar electrodes, concentric needle elec trodes, and single fiber electrodes.…”