Combination of sacral nerve and tibial nerve stimulation for treatment of bladder overactivity in pigs

Sacral nerve and tibial nerve stimulation have been singly used to treat overactive bladder (OAB). This study evaluated the effects of both combined stimulation on treating bladder overactivity in pigs and explored a novel treatment modality for OAB. An implant-driven stimulator of the S3 spinal nerve was implanted in 5 pigs. The contralateral tibial nerve was stimulated by an external stimulator. Multiple cystometrograms were performed to determine the effects of single nerve stimulation and combination sacral nerve stimulation (SNS) and tibial nerve stimulation (TNS) on the micturition reflex by infusing normal saline (NS) or acetic acid (AA). AA-induced bladder overactivity significantly reduced bladder capacity (BC) to 16.3 +/- 2.2% of the NS control level (389.4 +/- 27.68 ml; P < 0.01). When given a single stimulation, both SNS and TNS significantly increased the BC to 39.2 +/- 1.6% and 34.9 +/- 5.0% of the NS control level (P < 0.01), respectively. Combined SNS and TNS significantly increased the BC to 50.2 +/- 5.2% of the NS control level (P < 0.01) and induced a superior inhibitory effect than SNS or TNS alone (P < 0.05). Combination SNS and TNS induced a superior inhibitory effect on bladder overactivity in pigs compared to single stimulation and thus could be a novel treatment modality for OAB.