The usefulness of electrical stimulation for assessing pedicle screw placements

The purpose of this study was to further establish the efficacy of pedicle screw stimulation as a monitoring technique to avoid nerve root injury duri ng screw placement. The study population consisted of 662 patients in whom 3,409 pedicle screws were placed and tested by electrical stimulation. If s timulation resulted in a myogenic response at a stimulation intensity of 10 mA or less, the placement of the screw was inspected. Inspection was neces sary for 3.9% of the screw placements in 15.4% of the study population. Non e of the patients in the study experienced any new postoperative neurologic deficits. These findings provide guidelines for the interpretation of stim ulation data and support the use of this technique as an easy, inexpensive, and quick method to reliably assess screw placements and protecting neurol ogical function.