Preoperative C2-tilt as a potential indicator of postoperative trunk shift correction in congenital cervical/cervicothoracic scoliosis.

INTRODUCTION: Shifting of the trunk towards the convex side of the scoliotic deformity (trunk shift, TS), tilting of the head (head tilt, HT), coronal atlantoaxial dislocation (CAAD), and secondary scoliotic curves are clinical and radiographic findings usually seen in children with congenital cervical or cervicothoracic scoliosis. It may be anticipated, that secondary curves, TS, HT and CAAD are compensatory mechanisms to bring the spine into a balanced position and to enable horizontal gaze. Nevertheless, these mechanisms are frequently not sufficient. Surgery for congenital cervical or cervicothoracic scoliotic deformities aims to bring the unbalanced spine into a balanced position. These surgical procedures usually result in a relevant improvement of the coronal balance and may improve quality of life to these patients. The aim of our study was to investigate how HT and TS change after surgery and to identify exploratory associations related to correction of TS and HT.

METHODS: Retrospective analysis of CAT scans and X-ray images from patients with cervical or cervicothoracic congenital scoliosis treated between 2006 and 2022. 16 patients, mean age 7.4 Y.M, 8 girls, 8 boys. Pre- and postoperative measurements of TS, HT, Cobb angle of the main curvature (CA-MC), C2- and UEV- (Upper End Vertebra) tilt were taken from whole-spine images, and CAAD was measured from coronal CAT scan reconstructions using XERO-Viewer software (Agfa Health Care, Belgium). SPSS 29 was used for statistical analyses. ROC curve and Pearson correlation coefficients were calculated with a significance level of 0.05.

RESULTS: TS before surgery was 3.7° ± 4.3°, and 1.9° ± 2.3° (p = 0.863) after surgery at the last follow-up. HT before surgery was 9.2° ± 9.6°, and 3.3° ± 1.8° after surgery at the last follow-up (p = 0.16). A statistically significant association between preoperative C2-tilt and postoperative ΔTS was observed (r = 0.604, p = 0.013) in this exploratory cohort.

DISCUSSION: In pediatric patients with cervical or cervicothoracic scoliosis, head tilt and trunk shift are improved by adequate surgical procedures and preoperative C2 - tilt showed an exploratory association with the change of trunk shift. Due to the small number of cases, these findings solely represent tendencies towards improvement.