Micturition control by microstimulation of the sacral spinal cord of the cat: acute studies

The feasibility of using microstimulation of neural elements in the sacral spinal cord to effect micturition in cats has been assessed in acute experiments. Previous attempts at intramedullary stimulation have been limited by unwanted cocontraction of the bladder and the external urethral sphincter (EUS) or by side effects. Using microstimulation of parasympathetic preganglionic neurons or their efferent axons, the authors were able to repeatably elevate bladder pressure without simultaneously increasing EUS tone or eliciting undesired somatic contractions. Both stimulus amplitude and pulse width were effective in modulating bladder contractions but the stimulus frequency was not. Use of an interrupted duty cycle was helpful in preventing detrusor muscle fatigue during sustained periods of stimulation. Pulsing multiple microelectrodes implanted in the sacral spinal cord (especially bilateral pairs) enhanced elevation of bladder pressure over that elicited by stimulation with an individual electrode, but the effect was less than additive. These results have provided a basis for the development of a chronic spinal cord stimulation system suitable for controlling micturition