OBJECTIVETo evaluate the accuracy of computer-assisted pedicle screw installation and its clinical benefit as compared with conventional pedicle screw installation techniques.

METHODSTotal 176 thoracic pedicle screws placed in 42 thoracic fracture patients were involved in the study randomly, 20 patients under conventional fluoroscopic control (84 screws) and 22 patients had screw insertion under three dimensional (3D) computer-assisted navigation (92 screws). The 2 groups were compared for accuracy of screw placement, time for screw insertion by postoperative thin-cut CT scans and statistical analysis by X(2) test. The cortical perforations were then graded by 2-mm increments: Grade I (good, no cortical perforation), Grade II (screw outside the pedicle less than 2 mm), Grade III (screw outside the pedicle larger than 2 mm).

RESULTSIn computer assisted group, 88 (95.65%) were Grade I (good), 4 (4.35%) were Grade II (less than 2mm), no Grade III (larger than 2 mm) violations. In conventional group, there were 14 cortical violations (16.67%), 70 (83.33%) were Grade I (good), 11 (13.1%) were Grade II (less than 2 mm), and 3 (3.57%) were Grade III (larger than 2 mm) violations (P less than 0.001). The number (19.57%) of upper thoracic pedicle screws ( T(1)-T(4) ) inserted under 3D computer-assisted navigation was significantly higher than that (3.57%) by conventional fluoroscopic control (P less than 0.001). Average screw insertion time in conventional group was (4.56+/-1.03) min and (2.54+/-0.63) min in computer assisted group (P less than 0.001). In the conventional group, one patient had pleura injury and one had a minor dura violation.

CONCLUSIONSThis study provides further evidence that 3D computer-assisted navigation placement of pedicle screws can increase accuracy, reduce surgical time, and be performed safely and effectively at all levels of the thoracic spine, particularly upper thoracic spine.