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Volume 42 Number 2, March/April 2005
Pages 251 — 260

Abstract - Bladder-wall and pelvic-plexus stimulation with model microstimulators: Preliminary observations

James S. Walter, PhD;1-2* Mary Pat Fitzgerald, MD;2 John S. Wheeler, MD;  2-3 Bradley Orris, MD;2-3
Allison McDonnell;1 Robert D. Wurster, PhD1,4-5

1Research Service, Department of Veterans Affairs (VA) Edward Hines Jr. Hospital, Hines, IL; 2Department of
Urology, Loyola Medical Center, Stritch School of Medicine, Maywood, IL; 3Surgical Service, VA Edward Hines Jr. Hospital, Hines, IL; 4Department of Physiology and 5Department of Neurosurgery, Loyola Medical Center, Stritch School of Medicine, Maywood, IL
Abstract — Severe urinary retention is not a common condition, but may occur following some pelvic surgeries or other medical conditions. Electrical stimulation of the bladder has been examined as a means of managing this difficult problem. We conducted preliminary investigations in cats to prove the hypothesis that pelvic-plexus (bladder-neck) stimulation would produce greater micturition response with reduced side effects, such as animal movement or discomfort, than bladder-wall stimulation with electrodes implanted higher on the bladder wall. We used model microstimulators that mimic the look and function of commercial microstimulators, but that we constructed. We instrumented four female cats during a survival surgery. Animals recovered well and studies were conducted over a 1-month period in the conscious animal and under anesthesia. We performed a variety of studies with different stimulation parameters and electrode locations to evaluate our hypothesis. In the active animal, we supplied only low currents, but two animals responded to stimulation with bladder contractions and voiding. Following anesthesia, higher stimulating currents resulted in greater bladder contractions during stimulation in two of the three animals. In two cases, pelvic-plexus (bladder-neck) stimulation induced greater micturition responses than direct bladder-wall stimulation. In conclusion, we learned from these preliminary observations that stimulation at the pelvic plexus (bladder neck) may induce a better micturition response than stimulation higher on the bladder-wall. Newly available commercial microstimulators should be further studied for the treatment of urinary retention.
Key words: bladder, cystometry, electrical stimulation, electromyography, micturition, neuromodulation, urinary, urinary retention, urodynamics, veterans.

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