Functional pattern of sacral root stimulation in dogs. I. Micturition.

Prior to this study, electrostimulation of the ventral sacral roots had only limited success in evacuation of the bladder because dyssynergic sphincter contraction simultaneously increased urethral resistance. Thus, pudendal nerve blockade, pudendal neurotomy, selective peripheral neurotomy, or external sphincterotomy for reduction of sphincteric resistance seemed inevitable. To avoid those procedures we used electrical sphincter fatigue to induce effective micturition with stimulation of the ventral sacral roots. Stimuli of 200 Hz frequency rapidly fatigue the dyssynergic sphincteric response but not the desired detrusor contraction, eliminating the need of interference with the sphincteric activity.