Feasibility of Long-Term Tibial Nerve Stimulation Using a Multi-Contact and Wirelessly-Powered Neurostimulation System Implanted in Rats

Implant-driven tibial nerve stimulation (TNS) therapy is an effective technique for treating overactive bladder (OAB). However, the monopolar lead design in the currently available implantable devices pose long-term therapeutic challenges in terms of efficiently and selectively delivering electrical pulses to the target. Hence, the purpose of this study was to: (1) characterize the tibial nerve (TN) activation properties using a multi-contact implantable system and (2) evaluate the long-term stability of using such a neural interface in a pre-clinical model.

Ten adult Sprague-Dawley rats were used in this study. An implantable pulse generator (IPG) was surgically inserted in the lower back region. The lead wire with four active electrodes was placed in parallel with the TN. The threshold for activating the TN was confirmed via movement of hallux and/or toes as well as the foot EMG. The TN activation threshold was assessed bi-weekly, over a period of 12 weeks.

Channel 1 exhibited the lowest motor threshold at T0 (mean = 0.58 ± 0.10 mA). A notable increase in motor twitch intensity was observed during the first test session (2 weeks) following surgical implantation (75.8 ± 30.5%; Channel 1). Among the ten rats tested, eight rats successfully completed the 3-month study.

Results from this study demonstrate the long-term feasibility of achieving TNS with a multi-contact implantable device in a pre-clinical model. Future studies are warranted to assess the effects of using such a wirelessly-powered system for treating LUT symptoms in patients.

Urology. 2016 Jan 16 [Epub ahead of print]

Zainab Moazzam, Jason Paquette, Austin R Duke, Navid Khodaparast, Paul B Yoo

Institute of Biomaterials and Biomedical Engineering, University of Toronto, Ontario, Canada., Nuviant Medical Inc., Dallas, TX, USA., Institute of Biomaterials and Biomedical Engineering, University of Toronto, Ontario, Canada; Department of Electrical and Computer Engineering, University of Toronto, Ontario, Canada. Electronic address: .