Specific Sagittal Curve Patterns of Cervical Spine in Adolescent Idiopathic Scoliosis (AIS)

ABSTRACT

STUDY DESIGN: A retrospective study. OBJECTIVES: To evaluate the sagittal alignment of cervical spine in AIS. SUMMARY OF LITERATURE REVIEW Little has been known about the sagittal curve patterns of cervical spine in AIS patients. MATERIALS AND METHODS: One-hundred-thirty-three AIS patients were checked by scanographs and followed up for more than 2 years were divided into cervical kyphosis (> or =+5degrees), lordosis (< or =-5degrees) and straight (-4degrees~+4degrees) groups according to the sagittal curves of cervical spine (C2~C7). Each group was evaluated for thoracic kyphosis, lumbar lordosis, sagittal balance and Cobb's angle on coronal plane. Of the patients, 49 were treated by braces, 84 were surgically corrected (rod derotation in 52, direct vertebral rotation (DVR) in 32). RESULTS: At the initial radiographs, cervical kyphosis was found in 97, lordosis in 23 and straight in 13 patients. In the kyphosis group, cervical kyphosis showed typical patterns of angular kyphosis. Thoracic and upper T-kyphosis (T1~T5) were lower than those in the cervical lordosis group (p=0.000, 0.001, respectively.) Other factors showed no significant differences between the groups. Patients treated by conservative management or by rod derotation had no significant differences in cervical kyphosis during the follow-up periods, though the thoracic hypokyphosis was surgically corrected. On the contrary, patients who were treated by DVR restored cervical lordosis (14/32=43.8%) from initial state showed significant differences in both conservative and rod derotation groups (p=0.008, 0.002, respectively). CONCLUSIONS: Cervical kyphosis in AIS was a compensatory curve correlated with both thoracic hypokyphosis and rotational deformity. Rotational corrections should be considered during the surgical treatment.