In-Human Demonstration of High-Frequency Reversible Electrical Motor Nerve Block Compared to Selective Neurectomy – a proof-of-concept study.

Objective This is an in-human proof-of-concept series of cases that tested the possibility of replicating the effect of selective neurectomy with a high-frequency stimulation-generated nerve conduction block (HFNB). Design During the selective tibial neurectomy surgery for spasticity in four participants, the exposed nerve was stimulated at 10 kHz with a commercially available linear 8-contact electrode passed adjacent to the nerve under direct vision. Proximal stimulation was performed using a bipolar probe 1 cm proximal to the blocking electrode. The effect of block and proximal stimulation was recorded using the continuous EMG. High-frequency stimulation was stopped to assess reversibility. Subsequently, a neurectomy was performed, and direct stimulation testing was done proximal and distal to the neurectomy site. The effects of neurectomy on EMG were compared to those obtained with an HFNB. Results In all patients, an onset response was seen, after which a graded partial to complete block was obtained. HFNB was fully reversed shortly after stopping the stimulation. The EMG for proximal stimulation post-neurectomy was comparable to that with HF-stimulated block. Conclusion This demonstration of reversible electrical nerve block is a milestone towards the clinical implementation of high-frequency stimulation-mediated motor block for spasticity.