SACRAL ROOT STIMULATION FOR CONTROLLED MICTURITION - PREVENTION OF DETRUSOR-EXTERNAL SPHINCTER DYSSYNERGIA BY INTRAOPERATIVE IDENTIFICATIONAND SELECTIVE SECTION OF SACRAL NERVE BRANCHES

Electrical stimulation of the S2 nerve root can be used to produce det rusor contraction and voiding in patients with spinal cord injury, but concurrent stimulation of the external urethral sphincter causes detr usor-sphincter dyssynergia. This has been managed with a second surgic al procedure, peripheral transection of the pudendal nerve. In this st udy, performed in dogs after spinal cord transection, laminectomy and ventral foraminotomy permitted tracing of the S2 root into the pelvis, where its branches were identified by electrical stimulation and urod ynamic recording. The pudendal (somatic) branch was sectioned; the aut onomic branch innervating the detrusor was preserved. Electrical stimu lation of the proximal S2 root then produced detrusor contraction with out contraction of the external urethral sphincter. This approach, whi ch requires a single operation and spares pudendal nerve functions med iated by nerve roots other than S2, may enable a neurostimulator to pr ovide effective voiding, without detrusor-external sphincter dyssynerg ia, in man.