Selective Block Techniques of Urethral Sphincter Contractions in Sacral Anterior Root Stimulation

Conventional sacral anterior root stimulation (SARS) results in simultaneous activation of both, the detrusor muscle and the external urethral sphincter. We evaluated the possibilities of different neurostimulation techniques to overcome the stimulation induced detrusor-sphincter-dyssynergia and to achieve a physiological voiding. The literature was reviewed on different techniques of sacral anterior root stimulation to achieve selective stimulation of the bladder. The current sacral neurostimulation of the bladder including the principle of poststimulus voiding would be improved, if selective detrusor activation could be obtained. This is possible with the application of selective neurostimulation in techniques of anodal block, high frequency block, depolarizing prepulses and cold block. Anodal block technique and cryotechnique are excellent methods for selective bladder activation and thus improve of stimulation induced voiding pattern. Index terms sacral nerve roots, selective neurostimulation, posterior rhizotomy, spinal cord injury, bladder control