Bladder pacemaker: scientific basis and clinical future.

Complete intermittent emptying of the denervated bladder is essential to maintain the integrity of the urinary tract. Intraspinal extradural segments of the sacral roots in the canine can be stimulated electrically to induce bladder emptying effectively, especially in conjunction with selective neurotomy to make the stimulus pure autonomic effect on the bladder wall itself. With varying parameters of stimulation, one also can induce sustained voluntary sphincter activity to maintain continence--which obviates the problem of skeletal muscle fatigue. Combination of the two--detrusor stimulation for emptying and sphincteric stimulation to achieve control--are the first steps toward utilization of an electronic bladder pacemaker in the presence of an intact reflex arc. Its use in humans will be possible in the near future.