OBJECTIVE: To evaluate the placement of pedicle screws in the vertebrae of the thoracic and lumbar spine in patients with scoliosis using the"free hand" technique. METHODS: Evaluation of CT scans of 284 pedicle screws in 15 patients (seven men and eight women) aged between 12 and 39 years (mean 16.7 years) with scoliosis. The screws were inserted from T2 to S1 for the following conditions: two congenital scoliosis and 13 neuromuscular, to evaluate the placement of screws in relation to the walls of pedicles. RESULTS: Regarding the cortical pedicle screws, 244 (86%) were positioned between the cortical or just touching it. Lateral cortical lesion was seen in 16 screws and medial cortex lesion in 13 screws, being greater the number of violations in the thoracic vertebrae. CONCLUSION: The use of pedicle screw instrumentation in thoracic and lumbar vertebrae for scoliosis proved safe and effective when applied to different levels with the "free hand" technique. In the thoracic vertebrae, the pedicular cortical violations were more frequent, but did not impair the stability of fixation and did not injure the neural, vascular and visceral structures.
Thoracic vertebrae; Lumbar vertebrae; Scoliosis; Bone screws
