Study background: A retrospective study to compare the rate of facet joint violation (FJV) in lumbar posterior spinal instrumentation using open pedicle screw, percutaneous pedicle screw, and cortical bone trajectory (CBT) technique. CBT is a new posterior spinal instrumentation technique in which a more caudal entry point can minimize iatrogenic damage to the cranial facet joint. Only one recent study reports incidence of FJV of 11%; however, no previous reports comment on radiological outcomes comparing to traditional open and percutaneous screws. Methods: We reviewed 90 patients who underwent lumbar posterior spinal instrumentation from January 2016 to June 2017. Postoperative computer tomography scans were performed to evaluate FJV. Incidence of FJV was graded by three reviewers according to Seo classification. Results: Totally, 446 screws (open 43.4%, percutaneous 37.8%, CBT 18.9%) were inserted. Among these, 6.3% (28/446) had screw head or rod in contact with facet joint and 0.9% (4/446) had screws directly invaded the facet joint. Overall, FJV was 7.2% (CTB = 3.4%, open = 10.4%, and percutaneous = 4.5%, p = 0.075). Conclusion: CBT technique has potential advantage in reducing FJV. It has a unique entry site at lateral aspect of pars interarticular with a caudomedial to craniolateral pathway. It is a reasonable alternative to open or percutaneous techniques in lumbar posterior spinal instrumentation.
Comparison of facet joint violation in lumbar posterior spinal instrumentation using different techniques including cortical bone trajectory
