Cervical vertebral maturation (CVM) stage as a supplementary indicator for the assessment of peak height velocity (PHV) in adolescent idiopathic scoliosis (AIS).

Abstract

Radiographic methods in evaluating the skeletal maturity include Risser sign and Tanner-Whitehouse score. They are either inappropriate or too complex for a busy clinic setting. The cervical vertebral maturation (CVM) stage is commonly used in orthodontics but has been less acknowledged in studies of spinal growth. The purpose of this study was to evaluate whether the CVM stage could be used as an alternative to Risser sign in determining peak height velocity (PHV). This was a two-stage study. Inclusion criteria for stage I study were adolescent female idiopathic scoliosis (AIS) patients, aged between 9-16 years old, who had undergone full spine imaging with clear visibility of the cervical spine. Patients in the stage II study had follow-up through CVM stage 2-4. The correlation between CVM and Risser was analyzed. The spinal growth parameters were measured at each follow-up, and the growth velocity of parameters (PaGVs) was calculated. The PaGVs at CVM stage 2-4 were further compared. A total of 170 AIS patients were included for stage I study (mean age 12.7 years). The CVM stages were found to correlate strongly with the Risser sign (r=0.85, P<0.01). For those patients with Risser stage 0 with closed TC, 71% were CVM stage 3. Fifty-one patients were included for stage II study. The stature growth velocity averaged 5.4 cm/year in CVM stage 2 patients and 6.3 cm/year in CVM stage 3 patients, which was significantly greater growth than that in CVM stage 4 patients (3.3 cm/year, both P<0.01); similarly, the growth velocity of arm span, trunk height, and spinal lengths were also significantly higher in CVM stage 3 patients compared to CVM stage 2 and 4 patients. The CVM stage could provide an alternative option for the assessment of skeletal maturity of subjects with idiopathic scoliosis. CVM stage 3 may be a new sign of PHV.