Analysis of sagittal curvature and its influencing factors in adolescent idiopathic scoliosis

This study aimed to explore the characteristics of changes in the sagittal arrangement of the spine between adolescent patients with idiopathic scoliosis (AIS) and normal adolescents, the risk factors for AIS and the factors affecting the progress of AIS. X-ray images of the full length of the spine in standing position were taken in AIS patients and normal adolescents. Radiographic measurements made at intermediate follow-up included the following:C(1) and C(2) cervical lordosis and C(2) - C(7) curvature of cervical lordosis, C(2)-C(7)sagittal horizontal distance (C(2)-C(7)SagittalVerticalAxis, C(2)-C(7)SVA), TS-CL, after thoracic lobe (Thoracic Kyphosis, TK), thoracic lumbar segment Angle (thoracolumbar kyphosis, [TLK]), lumbar lordosis Angle (Lumbar Lordosis, LL), sacral slope Angle (Sacrum Slope, SS), pelvic tilt Angle (Pelvic Tilt, PT), pelvic incidence (PI), L(5) Incidence (Lumbar5 Slope (L(5)S), L5 incidence (Lumbar5 Incidence (L(5)I), sagittal horizontal distance ((C)SVA), lower depression Angle of the 2nd cervical spine. The difference of sagittal plane parameters between AIS group and normal adolescent group was compared. To evaluate the progress of AIS, correlation analysis was conducted between diagonal 2 and other parameters. The main risk factors of AIS were determined by binary Logistic analysis. The (C)SVA of AIS patients was higher than that of healthy adolescents (AIS: 27.64 ± 19.56) mm. Healthy adolescents: (17.74 ± 12.8) mm), L5S (AIS: 19.93°= 7.07° and healthy adolescents: 15.38°= 7.78°, P = .024 < .05), C(2) downward sag Angle (AIS: 15.12°= 2.7°;Healthy adolescents: 12.97°= 4.56°); AIS patients had lower TS-CL (AIS: 22.48 ± 6.09 and healthy adolescents: 28.26°= 10.32°), PT (AIS: 10.42°= 4.53° and healthy adolescents: 15.80°=7.68°), (AIS: 41.87°=9.72° and healthy adolescents: 48.75°= 8.22°). The main risk factor for idiopathic scoliosis in adolescents was L(5) (OR = 1.239, 95%CI = 1.049–1.463, P = .012 < .05). L(5)S is a major risk factor for idiopathic scoliosis in adolescents. The larger PI is, the higher the risk of scoliosis progression is. In AIS patients, lumbar lordosis is increased, cervical lordosis is reduced, and even cervical kyphosis occurs.