What can we learn from scoliosis in children with the 22q11.2 deletion syndrome? Prognostic factors at pre-adolescent age for fast progressive, mild and self-resolving forms during adolescence.

Abstract

Introduction: Longitudinal data starting before adolescence and before curve onset, may elucidate prognostic factors for later scoliotic curve development. The aim is to predict the maximum curve acceleration (MCA; °/month) and the final curve progression in a cohort of 22q11.2DS subjects screened for scoliosis.

Methods: Scoliosis screening starts immediately after 22q11.2DS diagnosis. A minimum of 2 years follow-up, two assessments, Risser 0, open triradiate cartilage at start, were the inclusion criteria. Risser ≥ 3 corresponded to skeletally matured. Linear and logistic binary mixed effect models accounting for patients nested into multiple measurement occasions were created to predict MCA during adolescence and progressors (progression to ≥ 30) versus non-progressors (no scoliosis or < 30 at last follow-up).

Results: 161 subjects (59% females) with a mean baseline age 8.7 ± 2.4 years, follow-up of 4.2 ± 2.4 years and having reached skeletal maturity. Ultimately, 19 subjects became progressors and 142 became non-progressors. Curve magnitude at baseline was 8.8 ± 5.9° (range 0-50), at final follow-up 11.6 ± 12.4 (0-77). The mean curve acceleration was + 0.1 ± 0.5°, respectively + 0.2 ± 0.5°for non-progressors vs progressors during the acceleration phase. A linear mixed model showed that the triradiate cartilage closure accelerates MCA by 2.6 when adjusted for age and female gender. In a logistic mixed model, when the triradiate cartilage closes, the OR of reaching the MCA before the next follow-up is increased by 4.60 (CI95% 2.34-8.90 p < 0.001). No evidence for prognostic value of Risser in all derivated models.

Conclusion: We found no evidence for the parameters in the coronal, sagittal nor transverse plane before curve onset acting as prognostic factors for curve behavior. In the prediction model on a longitudinal database that starts in many patients before scoliosis, no clear radiographic discriminant for later progressive scoliosis could be identified. The closure of the triradiate cartilage resulted as the best sign of pubertal spurt onset and scoliosis acceleration.