Clinical differences in preoperative symptoms and surgical outcomes between early and late-teen patients with Lenke type 5C adolescent idiopathic scoliosis

Purpose This study aimed to compare the clinical features and postoperative outcomes in patients with Lenke type 5C AIS in the early and late teens. Methods The study included eligible patients with AIS aged < 20 years with Lenke type 5C curves who underwent selective thoracolumbar/lumbar (TL/L) fusion. The patients were divided into two groups according to the age: younger (11–15 years) and older (16–19 years). Demographic data, radiographic parameters, and 22-item scoliosis research society questionnaire (revised) (SRS-22r) scores were compared. Results Seventy-three (female: 69, male: 4, mean age: 15.1 years) patients were included. There were 45 and 28 patients in the younger and older groups, respectively. The older group exhibited a significantly smaller TL/L curve than the younger group, whereas no between-group differences were identified regarding curve flexibility and fusion length. The change in coronal balance and subjacent disc angle from preoperative to 2 years after surgery was significantly greater in the younger group, although each curve was equally corrected. Preoperative SRS-22r scores in the older group were significantly worse; however, they improved to the level of the younger group at 2 years after surgery. Postoperative coronal malalignment was observed in six patients (21.4%) in the older group, whereas no cases in the younger group ( p < 0.05). Conclusion In patients with Lenke type 5C AIS, we showed that late teens had significantly worse SRS-22r scores than did early teens. Postoperative coronal malalignment was frequently observed in the late teens due to the reduced ability of compensation by subjacent disc wedging.