[The assessment of accuracy and safety of thoracic pedicle screw placement in the fracture of thoracic spine].

Objective: To investigate the accuracy and safety of pedicle screw placement in the fracture of thoracic spine.

Methods: On the basis of imaging for the fracture of thoracic spine of 50 cases, the screw prick point, angle, depth and diameter were measured and defined on the thoracic vertebrae pedicle by CT thin-slice scan in standard prone in all cases. The accuracy and safety of screws placement was evaluated with X-ray and CT thin-slice scan in all cases postoperative.

Results: Among of 240 thoracic pedicle screws that were inserted in 50 cases, 220 screws (91.7%) were fully contained within the cortical boundaries of the pedicle, 20 screws (8.3%) were misplaced, 7 screws (2.9%) laterally, 5 screws (2.1%) anterolateral and 2 (0.8%) of it demonstrated aortic abutment, 3 screws (1.3%) caudad perforations of the pedicle, 3 screws (1.3%) expended the wall of the pedicle to inside, 2 screws (0.8%) were misplaced in vertebral canal according to X ray and CT thin-slice scan. When comparing screws in different part of thoracic, there was a significant difference.

Conclusions: Preoperative CT measurement of the thoracic pedicle in the treatment of thoracic fracture can provide important data. It is important factors for thoracic pedicle screws that can be placed safety with guided by intraoperative fluoroscopic imaging and anatomic landmarks. CT thin-slice scan can evaluate accuracy misplace of thoracic pedicle screws, and show anatomic place surroundings of thoracic pedicle screws postoperative. More misplaced screws are seen proximally.