Electromyography monitoring for percutaneous placement of iliosacral screws

Objective: To report our experience with the use of continuous electromyography (EMG) for placement of iliosacral screws. Data Sources: Concurrently acquired data as well as patient charts, intraoperative EMG records, x-rays, and pelvic computed tomography (CT) scans. Design: The monitored group of twenty-nine patients was studied prospectively. The control group consisted of twenty-two patients studied retrospectively. Setting: Level One trauma center. Methods: Continuous electromyograms were recorded for twenty-nine patients and compared with those from a group of twenty-two antecedent patients who were not monitored. The primary parameter of interest of this study was the presence or absence of neurologic change after iliosacral screw placement. This information was obtained prospectively in the study group and by retrospective review in the historical control. Results: Four patients in the control group had postoperative and/or sensory motor changes prompting a postoperative CT scan; in each of these patients, a misdirected screw was identified and subsequently removed in a second procedure. There were no neurologic changes subsequent to placement in the twenty-nine patients who were monitored (7.5 percent versus 0 percent; p = 0.029, Fisher's exact test). All monitored patients had postoperative CT scans and showed the screw in a safe position with no significant violations of the S1 tunnel. Conclusion: Continuous EMG monitoring during iliosacral screw placement may be a useful neuroprotective tool.