Utilization of intraoperative electromyography for selecting targeted fascicles and determining the degree of fascicular resection in selective tibial neurotomy for ankle spasticity

Abstract

Selective tibial neurotomy (STN) is an effective neurosurgical intervention for treating ankle spasticity. The authors use intraoperative electromyography (EMG) for selecting targeted fascicles and determining the degree of fascicular resection in STN. This study reports surgical techniques and outcomes of the operation. Participants who underwent STN with utilization of intraoperative EMG were recruited. Modified Ashworth Scale (MAS), passive range of motion (PROM) of the ankle in plantar flexion and dorsiflexion, Massachusetts General Hospital Functional Ambulatory Classification (MGHFAC) and ability to attain full plantigrade stance were assessed pre- and postoperatively. Twenty-one STNs were performed in 15 patients. The mean pre- and postoperative MAS and PROM were 2.8 and 0.4 (p < 0.001), 39.5(o) and 66.0(o) (p < 0.001), respectively. The mean level of MGHFAC was improved from 3.3 preoperatively to 4.9 postoperatively (p < 0.01). Six non-ambulators had significant amelioration in MGHFAC level. Postoperatively, 19 of 21 lower limbs achieved full plantigrade, and 6 patients could perform selective voluntary motor control of the ankle. STN is an effective procedure for spastic ankle in well-selected cases. Intraoperative EMG helps in selection of targeted fascicles, increases objectivity in neurotomy and prevents excessive denervation.