INTRAOPERATIVE MONITORING WITH STIMULUS-EVOKED ELECTROMYOGRAPHY DURING PLACEMENT OF ILIOSACRAL SCREWS - AN INITIAL CLINICAL-STUDY

A consecutive series of twenty-seven patients who had thirty acute uns table (type-C) fractures of the pelvic ring was studied prospectively to evaluate the use of stimulus-evoked electromyography to decrease th e risk of iatrogenic nerve-root injury during the insertion of iliosac ral screws. A prerequisite for inclusion in the study was a normal neu rological status preoperatively; somatosensory evoked potentials were monitored to further document the neurological status both before and after insertion of the screw or screws. A total of fifty-one iliosacra l screws were inserted, and a current threshold of more than eight mil liamperes was selected as the level that indicated that the drill-bit was a safe distance from the nerve root. Four of the fifty-one screws were redirected because of information obtained with stimulus-evoked e lectromyography. Postoperatively, all patients had a normal neurologic al status, Computerized tomography, although not accurate for detailed measurements, demonstrated that all of the screws were in a safe, int raosseous position, Monitoring with stimulus-evoked electromyography a ppears to provide reliable data and may decrease the risk of iatrogeni c injury to the nerve roots during operations on the pelvic ring.