Anterior release & posterior spinal fusion vs. posterior-only fusion in AIS patients with large magnitude thoracic curves

Purpose The surgical management of severe adolescent idiopathic scoliosis (AIS) remains a subject of ongoing discussion among spine-deformity surgeons. While there has been a prevailing shift towards posterior-only fusion (PF) techniques, anterior release with posterior fusion (ARPF) may still be valuable for the correction of large or stiff curves. This study compared the clinical and radiological outcomes of PF and ARPF in a high-volume spinal deformity unit. Methods Patients aged 10–18 years with AIS and a major thoracic curve ≥ 70 ° (Lenke Types 1–4), who underwent PF or ARPF between 2010 and 2019, with ≥ 2 years of follow-up were included. Correction index formed the primary outcome, complemented by several secondary radiological and clinical measures assessed preoperatively, at first-erect radiograph and final follow-up. Results Eighty-nine patients were included (PF = 51; ARPF = 38). Baseline characteristics were similar except ARPF patients were younger (13.7 vs 1.4.8, p = 0.001) and less skeletally mature (Risser 0–2: 60.5% vs 37.3%). Baseline Cobb angle was comparable ( p = 0.0634), but ARPF patients had stiffer curves ( p = 0.0257), reduced flexibility ( p = 0.0408), and achieved a significantly higher CI at final follow-up (248.2% vs. 168.1%, p = 0.0024). Operative time, blood loss and length of stay were greater for ARPF. Conclusions ARPF offers a corrective advantage for patients with stiffer curves and lower skeletal maturity, who are at risk of developing crankshaft phenomena. However, the increased operative morbidity supports PF alone as sufficient for most patients. These results highlight the importance of tailoring surgical strategy to curve characteristics and skeletal maturity to optimise correction and minimise risk.