Evaluation of Pudendal Nerve Block for Voiding after Spinal Cord Injury

Veterans Admin Palo Alto Health Care Sys, Palo Alto CA

Investigators

Abstract

Spinal cord injury causes many bladder complications for life, such as impaired bladder emptying, recurrent urinary tract infection and stones, kidney damage, and incontinence, which impair health and quality of life and result in considerable cost to health care systems, in spite of state of the art management using medications, appliances and surgery. These complications are often due to unco-ordinated and unwanted contractions of the bladder and the external urethral sphincter, the muscle that restricts the flow of urine out of the bladder through the urethra. Contraction of the sphincter has been managed by cutting the sphincter or the nerves to the sphincter, inserting cylindrical metal mesh stents to keep it open, and injection of muscle toxins into the sphincter, but none of these is ideal and some have significant complications, and many patients require intermittent or indwelling catheters to remove urine from the bladder, and these too have their complications. Recently a technique has been developed and refined to block conduction in nerves rapidly and reversibly using electrical stimulation, and this has been used in animals with chronic spinal cord injury to prevent contraction in the pudendal nerves to the sphincter and to allow reliable emptying of the bladder. This project proposes to test this technique for the first time in human subjects with chronic spinal cord injury, using electrodes that can be inserted through a needle and left in place for several days and used to apply electrical stimulation while measuring the ability of human subjects to empty the bladder in the laboratory. After making these measurements the electrodes will be removed by pulling gently on them. If this project is successful it will justify the development and testing of a stimulation system that can be fully implanted by surgery to provide long term management of this problem.