Radiological follow-up strategies in adolescent idiopathic scoliosis patients: A best evidence synthesis by systematic review.

Introduction: Patients with adolescent idiopathic scoliosis (AIS) undergo frequent radiographic evaluations due to the progressive nature of the deformity. However, current intervals between radiographs are based on expert consensus, rather than scientific evidence. Research question: To determine appropriate radiological follow-up intervals based on estimated monthly deformity changes in observed AIS patients. Material and methods: A systematic search was conducted in MEDLINE, EMBASE and the Cochrane Library from inception until January 8th, 2025. Inclusion criteria were: (1) studies including AIS patients observed using radiological follow-up alone, and (2) reporting average monthly curve progression or curve progression rate over a pre-determined follow-up interval. Methodological quality was assessed using the Quality in Prognostic Studies (QUIPS) tool. Deformity progression rates were defined to categorize patient- and radiological characteristics into low-, moderate-, or high-grade progression with corresponding recommendations for radiological follow-up. Results: Nine eligible studies were identified, including a total of 2326 AIS patients. Monthly curve progression was sufficiently reported for four prognostic factors. Most articles reported curve progression rates according to patients' bone age, dictating a six-month radiological follow-up interval until skeletal maturity is approached. Nearly all studies showed a high risk of bias along with heterogeneity in the prognostic factors analyzed for curve progression. Thus, data regarding the suggested radiological follow-up intervals was inconclusive. Discussion and conclusion: Due to the high risk of bias and heterogeneity among the included studies, conclusive evidence could not be established. Limited evidence suggests radiographic follow-up every six months until skeletal maturity is approached, with annual follow-up thereafter.