Diagnostic accuracy of pedicle screw placement using triggered electromyographic thresholds from stimulation over the pedicle screw compared to the stimulation within the pedicle hole.

The use of pedicle screws is a globally practised standard for all surgical treatments for spinal pathologies like deformity correction, degenerative disks, spondylolisthesis, etc. The risk is potential canal perforation resulting in irritation or compression of nerve roots. Malposition of PS can lead to structural instability and new onset motor or sensory deficits postoperatively. To decrease this risk, pedicle screw (PS) stimulation, an intraoperative neurophysiological monitoring (IONM) technique, was introduced to ascertain the proper placement of the PS into the pedicle hole along with other techniques like intraoperative fluoroscopy, direct inspection, and neuronavigation. Direct stimulation over the pedicle screw has been shown to have high specificity but clinically unacceptable low sensitivity. Hence, triggered electromyographic (t-EMG) cannot be solely relied upon for appropriate PS placement. However, using a stimulating probe inside the pedicle hole showed higher sensitivity than PS stimulation. In this study, we want to compare the diagnostic accuracy of pedicle hole stimulation with that of pedicle screw stimulation.