Pedicle Screw Fixation of the Thoracic Spine

ABSTRACT

Pedicle screw instrumentation has proven to be reliable and effective in the surgical management of lumbosacral disorders, yet the appropriateness in the thoracic spine is not known. To evaluate the accuracy of the pedicle screw placement in the surgical management of the thoracic spinal disorders and to establish its risks and benefits, a prospective study was designed. One hundred and two thoracic pedicle screws in 22 consecutively treated patients were investigated after surgery by computed tomography scans. Twenty-one(20.5%) screws penetrated the pedicle cortex or the vertebral body anterior cortex. Three screws penetrated the medial cortex of the pedicle by the averages of 2mm to a maximum 4mm. Fifteen screws(14.7%) penetrated laterally by an average of 1.5mm. There were 3 screws of caudal penetration. The screws inserted at T1-T8 revelaed a higher penetration rate than those inserted at T9-T12(35.7% versus 14.7%)(p<0.05). Hardware failures causing the preoperative defor-mity were seen in a patient to whom half the cephalad screws were laterally misplaced. However, there were no major neurologic complications. Although segmental pedicle screw fixation of the thoracic spine requires meticulous measures and considerable experience, it was therefore can be considered as a safe and effective method for stabilizing the thoracic spine.