Percutaneous pedicle screw placements: accuracy and rates of cranial facet joint violation using conventional fluoroscopy compared with intraoperative three-dimensional computed tomography computer navigation

The goal of this study was to compare the accuracy and cranial facet joint violation rates between percutaneous pedicle screw placements using conventional fluoroscopy and intraoperative 3-D CT (O-arm) computer navigation. We reviewed 194 pedicle screw of 28 consecutive patients who underwent minimally invasive lumbar or thoracic spinal stabilization. The accuracy of screw placement was evaluated according to two criteria published by Neo et al. and Upendra et al. Facet joint violation was evaluated according to the classification described by Babu et al. Upon Neo grading, CFT group had 19.4 % (14/72) pedicle breach rate and CT-IGN group had a 5.7 % (7/122) pedicle breach rate (p < 0.005). The same sets of screws were also assessed using the outcome-based classification established by Upendra. There were no screw caused neurovascular injuries (type 3 = 0) in both groups. The results showed that 87.5 % (63/72) screws had acceptable placements (type I) and 12.5 % (9/72) had unacceptable placements (type II) in CFT group. In contrast, 94.3 % (115/122) screw had acceptable placements (type I) and only 5.7 % (7/122) had unacceptable placements (type II) in CT-IGN group. Additionally, CFT group had a significantly higher facet joint violation rate of 30.5 % (11/36) than CT-IGN group that had a 3.8 % (3/79) violation rate (p < 0.005). This study indicated the use of intraoperative CT imaging (O-arm) navigation in PPS placement have very beneficial implications for MIS.