Biomedical subjects

J P Heine

Publications and source records attributed to J P Heine.

3 recordsLinked to original sources

PubMed1977

Intraspinal sacral root stimulation for controlled micturition.

The intraspinal extradural segments of the sacral nerves were stimulated in an effort to obtain the combination of maximal detrusor contraction and minimal outflow resistance essential for effective micturition. Each root was stimulated unilaterally and bilaterally. In addition, each was separated into its motor and sensory components and these components were then individually stimulated. It was found that the most effective result was obtained with stimulation of root S2. As in the experimental animal, sacral roots in the human have a long intraspinal course that makes them accessible for implantation of electrodes. It is hoped that ongoing experiments will lead to the development of a chronically implantable sacral root electrode--thus providing a tool for efficient emptying of the denervated bladder.

Animals↗

PubMed1976

Urodynamic evaluation of a chronically implanted bladder pacemaker.

A "chronic" study of an implantable bladder pacemaker revealed that, although the electrode array did not significantly impair vesical function during the 10 weeks of research, electric stimulation did spread to the voluntary perineal musculature. There was also a drop in bladder response to the same stimulation parameters, probably due to progressive development of fibrous reaction and encasement of electrodes.

Animals↗

PubMed1975

Studies on the feasibility of urinary bladder evacuation by direct spinal cord stimulation. I. Parameters of most effective stimulation.

In 30 female dogs, spinal cord stimulation was tested to find the optimal parameters producing good voiding and, hopefully, total bladder emptying. Twelve different electrodes or application modifications were examined. Variable frequencies, stimulus duration, and voltages were applied. Search of the site of highest detrusor response (micturition center) was easily identifiable. It became obvious that electrode design was not of critical importance: the responses were basically the same whether we used the wrap-around electrode, which stimulates an entire level, or the coaxial electrode which theoretically limits the current spread around its minute exposed tip. The stimulation parameters that gave the best results were: 2 to 5 volts; frequency: 10 to 15 cps; duration 1 msec. The site of highest detrusor response was round vertebral level L5 1/2, corresponding to cord level S2-4. Generally, no voiding was obtained because of too high sphincteric contraction during stimulation; it appeared that a sphincteric center overlaps the micturition center in either direction. To achieve successful voiding during stimulation, a separation of these two centers with selective stimulation of the detrusor center is necessary, eleiminating sphincteric contraction.

Animals↗