Introduction: Pedicle screw misplacement in scoliosis surgery is well documented in adolescent idiopathic scoliosis (IS), but not in the non-idiopathic and skeletally immature population.
Objective: To evaluate the pedicle screw misplacement rate in children undergoing surgical treatment for all scoliosis etiologies.
Materials and Methods: 1042 pedicle screws were prospectively evaluated for misplacement by CT-scan in 54 children(mean:14.0y, range:4-20) undergoing PSI(mean Cobb: 63.2o, range: 30–112). Misplacement was defined as: >2mm for the medial cortex, >4mm for the lateral/anterior cortices. Scoliosis etiologies included:52% idiopathic, 22% congenital(CS), 26% neuromuscular scoliosis(NMS).
Results: 8.4% of screws were misplaced: 4.5% medially, 3.1% laterally, 0.08% anteriorly. Misplacement rates between IS(7.1%) and CS(11.5%,p=.066) trended towards significant difference. The misplacement rate for NMS(8.7%) was not higher when compared with IS(p=.413). Univariate analysis demonstrated no difference in misplacement rates in children . or .10 years of age(p=0.599). Differences in misplacement rates were found in: proximal(12.5%) vs. periapical(5.0%,p=.001) vs. distal screws(5.5%,p=.003); and T1(40%,p=.008) and T2(19%,p=.024) pedicle screws vs. average misplacement at other levels(8.4%). Multivarite analysis demonstrated no difference in misplacement rates between scoliosis etiology groups. T1 and T2 pedicle screws were 7.9 and 2.8 times more at risk of being misplaced than those at all other levels, respectively. No screws required removal or caused complications.
Conclusion: Only a consistent relationship between pedicle screw placement at T1 and T2 and higher misplacement rate was found.
Significance: Although there was a trend toward higher pedicle screw misplacement rate in CS after controlling for confounders, the misplacement rate in this heterogeneous population was the same or lower than reported in the AIS literature.