H-reflex in Spastic Lower Limb Cryoneurotomy

Overview

Spasticity is a common complication after many upper motor neurone disorders. Many surgical techniques have been introduced for patients with refractory spasticity though they are not without peri-operative risks. Cryoneurotomy is another procedure which is cheaper, faster and less invasive in comparison to other surgical interventions. While many studies support the use of cryoneurotomy for pain relief, there are not much studies on use of cryoneurotomy to manage spasticity. The purpose of this study to measure the effect of tibial nerve cryoneurotomy on electrophysiological and clinical spasticity measures in adult patients with spastic equinovarus or equinus foot, who will receive this procedure as a part of their treatment based on spasticity treatment available guidelines. The results will provide us valuable information like how long cryoneurotomy is effective, before regeneration happens.

Different surgical techniques, including muscle and tendon lengthening and neurotomy/neurectomy (surgical sectioning of a peripheral nerve) are reserved for patients with refractory spasticity. Cryoneurotomy which involves direct application of a low temperature probe to a nerve is another procedure, which is cheaper, faster and less invasive than surgical intervention, for the treatment of refractory spasticity. While many studies support using of cold temperature in pain relief (Ilfeld BM, 2017, Friedman, T. 2012), there are not much studies on use of cryoneurotomy to manage spasticity.This clinic has been using cryoneurotomy clinically with empiric success for 2.5 years. The initial results reveal significant increased active and passive range of motion in upper limbs and decreased clonus and improved gait after tibial neurotomy in lower limbs. Spastic equinovarus foot (SEF) which is a common type of lower limb spasticity is typically treated with focal botulinum toxin injections, bracing and therapeutic exercise, although the drawback of these treatments is the need for serial injections and frequent interactions with health care providers. Recently selective tibial neurotomy has been shown to more definitively treat SEF (Bollens B, et al.2011, Deltombe T, et al. 2015), but as mentioned above this is an invasive approach. In light of our promising clinical experience with cryoneurotomy, we propose to prospectively and systematically measure its effect on SEF, as an alternative to more invasive surgical procedures and the typical multi-modal approach. The data collection fro this project which is a single-centre, prospective cohort study will occur at the Victoria General Hospital (VGH) multidisciplinary spasticity clinic. Patients with spasticity are referred to this clinic for different procedures including cryoneurotomy. This study will not interfere or change the patients' medical care, and the assessments will be done for the patients who are already candidates for this procedure as a part of their treatment, besides other provided medical cares and have been accepted to receive that.These participants will be invited to have an extra electrophysiological test for being enrolled in this study, which will be performed before the procedure and at 1, 3 and 12 months after cryoneurotomy. In addition, the results of their routine physical examinations including spasticity degree and ankle passive range of motion will be collected in this study.