Pedicle screw placement in the thoracic spine: a randomized comparison study of computer-assisted navigation and conventional techniques

Objective: To evaluate the accuracy of computer-assisted pedicle screw installation and its clinical benefit as compared with conventional pedicle screw installation techniques. Methods: Total 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 thincut CT scans and statistical analysis by x2 test. The cortical perforations were then graded by 2-mm increments: Grade Ⅰ (good, no cortical perforation), Grade Ⅱ (screw outside the pedicle <2 mm), Grade Ⅲ (screw outside the pedicle >2 mm).Results: In computer assisted group, 88 (95.65%) were Grade Ⅰ (good), 4 (4.35%) were Grade Ⅱ (<2mm), no Grade Ⅲ (>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 (<2 mm), and 3 (3.57%) were Grade Ⅲ (>2 mm) violations (P<0.001). The number (19.57%) of upper thoracic pedicle screws ( T1-T4 ) inserted under 3D computer-assisted navigation was significantly higher than that (3.57%) by conventional fluoroscopic control (P<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<0.001). In the conventional group, one patient had pleura injury and one had a minor dura violation.Conclusions: This 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.