Neurophysiologic studies of the sacral reflex in women with "non-neurogenic" sacral dysfunction

To test different technical setups for stimulation and recording of the sacral reflex, provide confidence intervals and discuss the utility of the sensory threshold and the sacral reflex threshold in women with "non-neurogenic" sacral dysfunction.

All women without neurologic disorder, with normal neurologic examination, and bilaterally normal quantitative electromyography of the external anal sphincter (EAS) muscles referred consecutively for uro-neurophysiologic testing were included. The sacral reflex was elicited by single and double electrical stimulation of the clitoris, and the response detected by a needle electrode inserted separately into the left and right bulbocavernosus muscle (i.e., clitoro-cavernosus reflex), and in some women also inserted into the EAS muscle.

Thirty-one women, mainly with fecal and/or urinary incontinence, were studied. Recording of the sacral reflex from the bulbocavernosus muscle was found to be much clearer than from the sphincter muscles. On 13 sides on single and on 6 sides on double pulse electrical stimuli clitoro-cavernosus reflex latencies were found to be much longer compared to those obtained previously in women with intact sacral function.

The present study supports the findings of previous studies, which reported longer sacral reflex latencies in women with "non-neurogenic" sacral dysfunction. The difference might be explained by the lower excitation level of the sacral spinal cord neurons in some women with incontinence. Women with sacral dysfunction and prolonged sacral reflex latency need to be examined neurologically and electromyographically to confirm proximal neuropathic lesion.