Restoration of voiding in chronic urinary retention using the neuroprosthesis

Six women and one man presenting with chronic urinary retention for >1 year were restored to normal voiding after implantation of a neuroprosthetic device. Detrusor contractions could not be elicited in a preoperative urodynamic investigation, and failure of urethral sphincter relaxation was noted in all cases. Test stimulation of the pudendal and sacral nerve roots resulted in normal motor responses. A temporary wire electrode was inserted in either the S3 or the S2 foramen and the patient was connected to a self-controlled pulse generator for 3-5 days. Voiding returned within the first 24 h and continued for the duration of the test. Retention recurred after removal of the temporary wire electrode. Permanent electrodes were then inserted. Five patients continue to void normally at 2-48 months (mean, 16 months) postimplantation. These subjects demonstrate that chronic retention can be the result of impaired reflex triggering of the voiding reflex in the presence of completely normal motor pathways. Sacral nerve root stimulation can identify this subset of patients and restore their normal voiding function.