The use of mechanically elicited electromyograms to protect nerve roots during surgery for spinal degeneration.

Abstract

This study investigated the use of mechanically elicited electromyograms during the placement of pedicle screws in 89 patients undergoing surgery for spinal stenosis. Several methods for monitoring nerve roots are available. However, mechanically elicited electromyograms may be more sensitive to mechanical irritation of nerve roots by pedicle screws than by other methods. Mechanically elicited electromyograms were recorded in muscle groups innervated by cervical or lumbar nerve roots. Confirmation of surgical activity with the level of the electromyogram was correlated. Results indicated that mechanically elicited electromyograms are extremely sensitive to nerve root irritation. Compared to other methods, electromyograms are a viable alternative. Results from this study indicated that mechanically elicited electromyograms are sensitive and specific to nerve root firings and should be considered for use during the dynamic phases of surgery.