Electrostimulation to empty the neuropathic bladder has been the focus of our research for the past twelve years. In extensive animal studies, various sites of electrode implantation were evaluated--the spinal cord, pelvic nerves, detrusor muscle, and individual sacral roots. The most effective voiding was obtained by stimulation of the ventral component of selected sacral roots after their somatic contribution to the urinary sphincter had been sectioned. During the past two years, six human volunteers underwent laminectomy and implantation of sacral root electrodes. Various combinations of dorsal rhizotomy versus separation, pudendal neurotomy versus selective somatic sectioning, were added to sacral root implantation. We also studied high- and low-frequency stimulation and pudendal nerve blockade by xylocaine injection. The preliminary results are most encouraging. This proposal is designed to investigate: 1) the possible harmful effect of dorsal rhizotomy on detrusor contraction; 2) the incomplete elimination of the urethral sphincter by unilateral pudendal neurotomy or unilateral selective sectioning of the somatic component alone; and 3) the long-term effect of rhizotomy and somatic neurotomy on the sphincter muscles. Our animal experiments will carefully examine the effect of dorsal rhizotomy, pudendal and selective somatic neurotomy on bladder and sphincter function, as well as the metabolic and histologic changes in the sphincter muscles after these procedures. Ten patients (five men, five women) will undergo implantation over a three-year period with a combination of different techniques aimed at achieving maximal bladder response and eliminating urethral resistance during stimulation while maintaining continence in the bladder filling phase. We hope that, at the completion of this study, an effective, universally successful technique devoid of harmful effects on the bladder and sphincter will be available for general use to benefit the tens of thousands of patients with bladder and urethral dysfunction.
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