Effect of L5 spinal canal type on pedicle screw placement based on CT imaging: a retrospective clinical study

Purpose The objective of this study was to investigate the optimal entry point and pedicle camber angle for L5 pedicle screws of different canal types. Methods CT imaging data were processed by Mimics for simulated pedicle screw placement, and PD (Pedicle diameter), PCA (Pedicle camber angle), LD (Longitudinal distance), TD (Transverse distance), and PBG (Pedicle screw breach grade) were measured. Then they were divided into the Round group and Trefoil group according to the type of spinal canal. When comparing PD, PCA, LD, TD, and PBG, the two sides of the pedicle were compared separately, so they were first divided into the round-type pedicle group and the trefoil-type pedicle group. Results In the round-type pedicle group ( n = 134) and the trefoil-type pedicle group ( n = 264), there was no significant difference in PD and LD, but there was a significant difference in PCA between the two groups ( t = − 4.072, P