Objective: To explore the influencing factors of pedicle screw instrumentation and provide theoretical rationales for decreasing facet joint violation rate by radiological evaluations of superior-segment facet joint violation after pedicle screw instrumentation in transforaminal lumbar interbody fusion (TLIF).
Methods: A retrospective study was conducted for 101 patients undergoing lumbar fusion after failed conservative treatment between December 2011 and December 2013. According to the Seo classification, computed tomography was used for evaluating the position of pedicle screw with superior segment facet joint. And χ2 test was used to examine the associations between superior segment facet joint violation and gender, age, construct level, fusion length and transpedicular screw side.
Results: A total of 202 screws were evaluated. There were grade 0 (n =154, 76.2%), grade 1 (n = 43, 21.3%) and grade 2 (n = 5, 2.5%). In all screws, facet joint violation occurred in L5 segment more frequently than in any other segment (P < 0.05), left-side facet joint violation was more common than right-side one (P < 0.05). No statistical associations existed between violation rates and gender, age and fusion length.
Conclusion: During TLIF, there is a higher incidence of facet joint violation at right side and in L5 segment compared with other lumbar segments.