Evolution of Sagittal Spinal Alignment During Pubertal Growth: A Large-Scale Study in a Chinese Pediatric Population.

Abstract

BACKGROUND Previous studies have reported normative data for sagittal spinal alignment in asymptomatic adults. The sagittal spinal alignment change in European children was recently reported. However, there is a lack of studies on the normative reference values of sagittal spinal and pelvic alignment and how these parameters change at different growth stages in Chinese children. The aims of this study were to establish the normative reference values of sagittal spinopelvic parameters in Chinese children, to investigate their variation during growth, and to compare these parameters between Chinese and European populations. METHODS The radiographic data of 1,916 healthy Chinese children (female:male sex ratio, 1.02:1; mean age, 11.9 ± 4.3 years) were analyzed in a retrospective, single-center study. Full-spine radiographs were utilized to measure several sagittal parameters, including pelvic parameters, T1-T12 thoracic kyphosis (TK), and L1-S1 lumbar lordosis (LL). TK was divided into proximal, middle, and distal parts, and LL was divided into proximal and distal parts. Patients were stratified into 5 groups according to skeletal maturity (based on age, Risser sign, and triradiate cartilage status). RESULTS During skeletal growth, pelvic incidence (PI) increased from 31.3° to 38.4° (p < 0.001), and pelvic tilt (PT) increased from 7.8° to 12.2° (p < 0.001). There were also increases in LL (from 45.0° to 46.3°; p = 0.020) and proximal LL (from 14.5° to 15.9°; p = 0.023). The peak of change in PI occurred between Groups 1 and 2 (from 31.3° to 35.8°; p = 0.011). The peak of change in LL was observed between Groups 1 and 3 (from 45.0° to 47.7°; p = 0.008). The peak of change in proximal LL (from 14.5° to 15.9°; p = 0.039) and distal TK (from 6.1° to 6.9°; p = 0.039) occurred between Groups 1 and 5. A subgroup comparison showed that age and TK were significantly higher in male patients than in female patients across the skeletal growth groups. CONCLUSIONS This was a comprehensive study of sagittal alignment in a large cohort of Chinese children. These findings can serve as age, sex, and ethnicity-specific reference values for spine surgeons when assessing and planning correction surgery for pediatric patients. The sagittal alignment variations during skeletal growth were different from those in European children, representing a unique cascade effect occurring during skeletal maturation in the Chinese population. LEVEL OF EVIDENCE Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.