Magnetically Coupled Percutaneous Connector for Chronic Electrical Peripheral Nerve Stimulation and Recording in Awake Rats

A fast-growing field of neuroscience and medicine is the treatment of disease via electrical stimulation of the peripheral nervous system. Peripheral nerve stimulation delivers stimulation to nerves of the periphery where the target nerve can and is often located deep within the abdomen. Long-term preclinical animal models that demonstrate the safety and/or efficacy of electrical stimulation have predominantly used a skull mount to connect to neural interfaces. When targeting nerves of the extremities and abdomen, this mount location is less favourable due to its distance to the implant causing complications in surgery and to the longevity of the device in vivo. Objective: Here we aimed to develop and validate a chronic magnetic percutaneous connector designed for placement on the dorsal-lumbar aspect of the spine of awake, freely moving rats. Methods: A pedestal and external connector was developed, bench tested to assess for continuity, durability and disconnection forces, and validated in awake rats chronically implanted with an abdominal vagus nerve electrode array. The implanted pedestal and external connector were designed with custom PCBs, spring-loaded pins, magnets and biocompatible 3D printed housing. Results: The magnetic coupling mechanism allowed disconnection with minimal force, was highly reliable in maintaining electrical connection in awake rats and allowed recording of electrically evoked compound action potentials after chronic implantation. Conclusion: In conclusion, this percutaneous connector is a useful research tool for peripheral nerve stimulation studies. Significance: The connector described will allow investigation into the safety and efficacy of emerging neuromodulation therapies for the treatment of disease.