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

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 bladderwall 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.

Pudendal neuromodulation improves voiding efficiency in diabetic rats

“…Anesthetic effects were also a limitation in the present study. The VE in urethane‐anesthetized control rats was only approximately 75%, which is lower than the approximately 98–99% VE measured in conscious animals 31, 32. The results of the present study show that ES of the sensory branch of the pudendal nerve did not significantly alter VE (approximately 75%, Table III) in non‐diabetic rats with intact pudendal nerves, and this limitation presumably because anesthesia restrained the facilitatory effects of pudendal stimulation on bladder emptying.…”

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“…The voiding efficiency in intact anesthetized rats before acute spinal cord transection was only 77%, which is lower than the 98%~99% voiding efficiency measured in conscious animals [41,42]. These results reveal that the anesthetic effect is another limitation in the present study.…”

Non-invasive Neuromodulation of Spinal Cord Restores Lower Urinary Tract Function After Paralysis

“…Historically, a variety of electrical stimulation techniques have been proposed to improve urine storage by increasing capacity and reducing DO; and improve urine voiding by stimulating detrusor contraction and sphincter relaxation at patient-determined intervals. These strategies include direct electrical stimulation of the pelvic nerve (Holmquist, 1968 ), the sacral nerve (Sievert et al, 2010 ; Granger et al, 2013 ) or the pelvic plexus and bladder wall (Walter et al, 2005 ). While promising, these approaches have not been widely implemented due to their invasive nature and need for concurrent sensory denervation (e.g., the sacral nerve stimulator) or lack of long-term effectiveness (e.g., bladder wall plexus stimulator).…”