Accuracy of cortical bone trajectory screw fixation guided by spinous process clamp guide in lumbosacral vertebrae: A cadaver study

The purpose of this study was to access the accuracy of cortical bone trajectory screw placement guided by spinous process clamp (SPC).Eight formalin-treated cadaveric lumbar specimens with T12-S1 were used. A total of 96 screws were implanted in eight lumbar specimens.In the freehand (FH) group, clinically acceptable placement (grade A and B) was 40 screws (83.3%), meanwhile 44 screws (91.7%) in the SPC guide group (p = 0.217). The grade A screws in the SPC guide group were much more than that in the FH group (n = 40 vs. n = 31, p = 0.036). The misplacement screws (grade C, D, and E) and proximal facet joint violation (FJV) in the SPC group was comparable to the FH group.This cadaveric study demonstrate that implanting CBT screws guided by SPC guide was more accuracy and reduces severe deviations in important directions.