Feasibility of endovascular stimulation of the femoral nerve using a stent-mounted electrode array

Abstract

Objective: Electrical stimulation of peripheral nerves has long been a treatment option to restore impaired neural functions that cannot be restored by conventional pharmacological therapies. Endovascular neurostimulation with stent-mounted electrode arrays is a promising and less invasive alternative to traditional implanted electrodes, which typically require invasive implantation surgery. In this study, we investigated the feasibility of endovascular stimulation of the femoral nerve using a stent-mounted electrode array and compared its performance to that of a commercially available pacing catheter.
Approach: In acute animal experiments, a quadripolar pacing catheter was implanted unilaterally in the femoral artery to stimulate the femoral nerve in a bipolar configuration. Electromyogram (EMG) of the quadriceps and electroneurogram (ENG) of a distal branch of the femoral nerve were recorded. After retrieval of the pacing catheter, a bipolar stent-mounted electrode array was implanted in the same artery and the recording sessions were repeated.
Main Results: Stimulation of the femoral nerve was feasible with the stent-electrode array. Although the threshold stimulus intensities required with the stent-mounted electrode array (at 100-500µs increasing pulse width, 2.17 ± 0.87 mA - 1.00 ± 0.11 mA) were more than two times higher than the pacing catheter electrodes (1.05 ± 0.48 mA - 0.57 ± 0.28mA), we demonstrated that, by reducing the stimulus pulse width to 100 µs, the threshold charge per phase and charge density can be reduced to 0.22 ± 0.09 µC and 24.62 ± 9.81 µC/cm2, which were below the tissue-damaging limit, as defined by the Shannon criteria.
Significance: The present study is the first to report in vivo feasibility and efficiency of peripheral nerve stimulation using an endovascular stent-mounted electrode array.