RESUMEN
INTRODUCTION: To date there is no consensus on therapeutic indications in adolescent idiopathic scoliosis (AIS) with curvature between 30° and 60° at the end of growth. OBJECTIVE: The objective of this study was to assess outcome in patients with moderate AIS. MATERIAL AND METHODS: A multicenter retrospective study was conducted. Inclusion criteria were: Cobb angle, 30-60° at end of growth; and follow-up > 20 years. The data collected were angular values in adolescence and at last follow-up, and quality of life scores at follow-up. RESULTS: A total of 258 patients were enrolled: 100 operated on in adolescence, 116 never operated on, and 42 operated on in adulthood. Mean follow-up was 27.8 years. Cobb angle progression significantly differed between the 3 groups: 3.2° versus 8.8° versus 23.6°, respectively; P < 0.001. In lumbar scoliosis, the risk of progression to ≥ 20° was significantly higher for initial Cobb angle > 35° (OR=4.278, P=0.002). There were no significant differences in quality of life scores. DISCUSSION: Patients operated on in adolescence showed little radiological progression, demonstrating the efficacy of surgical treatment for curvature greater than 50°. Curvature greater than 40° was progressive and may require surgery in adulthood. Lumbar scoliosis showed greater potential progression than thoracic scoliosis in adulthood, requiring fusion as of 35° angulation. LEVEL OF EVIDENCE: IV, retrospective study.