Evaluation of Percutaneous Cryoneurotomy Compared to Surgical Open Neurotomy for the Management of Equinovarus Foot Deformity in Patients With Refractory Lower Limb Spasticity After Stroke

Surgical neurotomy will be performed under general anesthesia according to the previous description. Muscle relaxant drugs will not be used in order to prevent any interference with the intraoperative electrical stimulation. The patient will be placed in a prone position and a vertical cutaneous incision will be made at the popliteal fossa location. The tibial nerve will be dissected and the motor nerve branches of the soleus, gastrocnemius, tibialis posterior and flexor hallucis longus will be identified with intraoperative tripolar electrical stimulation. The selected motor nerve branches will be partially sectioned over a 5mm length under the microscope. The extent of nerve section will be determined according to the degree of spasticity and to the intraoperative residual muscular contraction under electrical stimulation

After the use of an aseptic technique with 2% chlorhexidine, betadine application and a local anesthesia with lidocaine 1% (3ml), percutaneous cryoneurotomy will be performed with METRUM CRYOFLEX device guided by ultrasound with 1.2mm cryoprobe at -89°C placed through a #16 angio guide. Electrical stimulation will be performed to confirm tibial nerve contact at 0.8 mV. The ice ball will be repositioned to two spots along the nerve. Each lesion will be treated for 2min cryoneurolysis at -89°C, followed by 2min without freezing (passive defreezing period) and 2min of cryoneurolysis at -89°C, based on cryotherapy for pain management.