Study Design: Prospective study
Objectives: To analyze and compare the cervical and thoracic sagittal curves between normal adolescents and patients with thoracic
adolescent idiopathic scoliosis (AIS).
Summary of Literature Review: There are no reports on cervical sagittal curves and its correlation with thoracic sagittal curves
Materials and Methods: The sagittal curves were analyzed in normal adolescents (N-adol group, n=23) and patients with thoracic
AIS (AIS group, n=26) who had thoracic curves ≥ 45˚. Lateral standing radiographs of the cervical spine with a elbow
straight and the whole spine with the hands on the clavicles were taken. The sagittal curves and balance were measured in the
following segments; C2-C7, T2-T5, T5-12, T2-12, T12-S1. Cervical lordosis (C2-C7) was measured in both cervical spine radiographs
and whole spine radiographs.
Results: In the N-adol group, the cervical lordosis was 9.2±14.6˚in the cervical spine radiographs and -0.6±12.9˚(‘-’ means
kyphosis) in whole spine radiographs. In the AIS group, cervical lordosis was -5.0±12.9˚in the cervical radiographs and -8.1±
12.7˚in the whole radiographs. The AIS group had significantly less cervical lordosis than the N-adol group. Thoracic kyphosis
of T5-12 and T2-12 was 24.1±10.6˚and 38.9±13.1˚in the N-adol group, respectively, and 17.8±9.4˚and 30.1±11.8˚in the
AIS group, respectively. There was a significant difference between the two groups (Ps<0.05). There was no significant difference
in thoracic kyphosis of T2-T5, lumbar lordosis and sagittal balance between the two groups (Ps>0.05). In the AIS group,
the cervical lordosis measured in the cervical spine radiograph showed a positive correlation with thoracic kyphosis of T2-5
(r=0.50, P=0.009) and T2-12 (r=0.57, P=0.003).
Conclusions: AIS patients had significantly less cervical lordosis and thoracic kyphosis than normal adolescents. Decreased cervical
lordosis in AIS had a significant correlation with their relative thoracic hypokyphosis.