2022 Volume 13 Issue 5 Pages 758-762
Introduction: Intraoperative triggered electromyography (tEMG) is used during instrumentation surgery for early detection of screw malposition. The association between tEMG findings through lumbar pedicle screw stimulation and neurological deficits, however, remains unknown. The purpose of this study is to assess whether a low threshold tEMG response to lumbar pedicle screw stimulation can serve as a predictive tool for neurological deficit.
Methods: Between February 2018 and April 2020, we measured both tEMG and transcranial electrical motor-evoked potential in 56 patients (294 screws). We utilized probe or screw stimulation, and tEMG was recorded from the lower extremity muscles. A stimulation threshold of <10 mA was considered to be positive. Perforation or malposition of screw or probe was evaluated in postoperative computed tomography (CT).
Results: The tEMG positive alert was detected in six screws (six patients), in whom screw insertion route was changed during operation. A trace of perforation by PS or probe was observed in postoperative CT in all six cases.
Conclusions: The tEMG could detect perforation of pedicle screw accurately. When tEMG was detected, a change in the screw insertion route is strongly recommended.
