Rosebrugh Bldg, Toronto, ON M5S 3G9
Room: RS 211
Overactive bladder (OAB) is a syndrome characterized by symptoms of increased urgency and frequency that affects 8-9% of Canadian adults. Percutaneous Tibial Nerve Stimulation (PTNS) is a minimally-invasive OAB therapy in which the tibial nerve is electrically stimulated by a needle electrode inserted directly above the ankle. The efficacy of PTNS has been proven clinically; however, success rates are highly variable and the mechanism of action is not fully understood. Recent work in our lab has shown significant decreases in bladder contraction frequency in anesthetized rats both during and after repeated trials of tibial nerve stimulation (TNS). To expand on our previous study, this current work additionally incorporates the estimation of bladder capacity and voiding efficiency to better characterize bladder function changes evoked by TNS at different stimulation amplitudes. To accurately estimate bladder capacity and voiding efficiency, tight control of input and output bladder volumes was ensured by disconnecting the ureters and collecting voided volumes. Bladders were catheterized with a suprapubic catheter and stimulation was provided via a custom-fabricated bipolar electrode placed around the tibial nerve at the ankle. Following a two-hour baseline infusion, four randomized 30-minute stimulation trials of different amplitudes were performed in each animal while recording bladder parameters. It is hypothesized that the TNS-evoked decrease in bladder contraction frequency observed in our previous study will correspond with an increase in bladder capacity in this work. In addition, it is expected that increasing the stimulation amplitude will correlate with an increased effect size. The results of this work will provide insight into the neural mechanisms that control urinary function and will guide the design of improved neuromodulation therapies.