Functional, Radiographic, and Patient-Reported Outcomes of Hybrid Fixation Versus Posterior Long Fusion for Double-Major Adolescent Idiopathic Scoliosis.

Background

Posterior spinal fusion (PSF) provides reliable deformity correction for adolescent idiopathic scoliosis (AIS); however, it reduces lumbar mobility because of the fusion of motion segments. Hybrid fixation, which combines thoracic PSF with thoracolumbar/lumbar vertebral body tethering (VBT), aims to preserve lumbar function while maintaining satisfactory deformity correction.

Methods

This retrospective, non-randomized comparative cohort study included 66 adolescents with double-major AIS treated with hybrid fixation (n = 30) or posterior long fusion (n = 36) at a single tertiary referral spine deformity center. Radiographic outcomes, lumbar flexibility, sagittal range of motion (ROM), lumbar core muscle strength (LCMS), SRS-22r Function scores, complications, and revision surgery were assessed after a minimum follow-up of 24 months. Multivariable regression analyses were used to identify independent predictors of postoperative functional outcomes.

Results

Both procedures achieved excellent correction of the main thoracic curve and satisfactory global spinal alignment. Posterior long fusion provided greater thoracolumbar/lumbar curve correction (p < 0.001), whereas hybrid fixation resulted in significantly better lumbar flexibility, sagittal ROM, and LCMS (all p ≤ 0.006). Radiographic tether breakage occurred in eight hybrid patients (26.7%), though most were asymptomatic; revision surgery was required in two patients (6.7% vs. 0%, p = 0.20).

Conclusions

Hybrid fixation was associated with better objective lumbar function than posterior long fusion, with satisfactory deformity correction, in adolescents with double-major AIS. This benefit should be weighed against a higher complication rate driven mainly by tether breakage, supporting individualized, shared decision-making for motion-preserving strategies.