Monitoring placement of high thoracic pedicle screws by triggered electromyography of the intercostal muscles

Description: Pedicle screw–based constructs provide a stronger basis for spinal instru- mentation and fusion than hooks. Placement of the screws within the pedicles is a technically challenging procedure. The orientation of the pedicles with respect to surface landmarks changes along the length of the spine and may be abnormal in the scoliotic spine. In fact, some pedicles may not even have a cancellous core. The medial wall of the pedicle forms one side of the spinal canal, and intrusion of the screw into the canal can lead to major neurologic damage. Breaches in the other pedicle walls can also cause neuro- logic deficits by irritating or damaging spinal nerve roots.
J.A. Norton, D.M. Hedden Can J Surg, Vol. 52, No. 3, June 2009 E47 (full text)