Nerve Root Block in Spasticity

In this work the investigators propose to briefly apply kilohertz frequency alternating current via PNS device placed next to the isolated nerve in 4 patients undergoing peripheral neurectomy, just before cutting the nerve. The intervention shall be performed utilizing EMG monitoring and mapping. After the muscular branches of the tibial nerve are exposed, proximal stimulation (1Hz) shall be applied to a selected branch with a bipolar electrode to produce muscle contractions. A high frequency (10kHz) blocking current shall be applied by placing a PNS electrode distally to the bipolar electrode and the EMG shall be recorded. The PNS electrode shall be removed from surgical field and further proximal stimulation done to confirm reversal of block (return to baseline) on the EMG. Then the nerve will be severed as a part of standard tibial neurectomy, and further proximal and distal stimulation shall be performed. The results will be compared to see if high frequency conduction block can physiologically mimic peripheral neurectomy; and obtain parameters of stimulation required for that.