Autograft Versus Allograft in Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis: Is There a Difference in...

Retrospective cohort study.

Assess the influence of graft type on the development of pseudoarthrosis in patients undergoing posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS).

Long-term bony fusion after PSF for AIS is crucial to preserve deformity correction, whereas pseudoarthrosis represents a concerning potential complication. Debate continues over the necessity of allograft bone grafting to achieve cost-effective spinal arthrodesis.

A retrospective comparative cohort study was performed in patients who underwent a primary PSF for treatment of AIS between 2010 and 2021 at a single tertiary institution. Exclusion criteria were age younger than 10 years, non-idiopathic scoliosis, non-posterior fusion approaches, or <2 years follow-up. Pseudoarthrosis was defined as radiographic loss of correction >10 degrees, or direct visualization of nonunion during reoperation. Patients were grouped according to whether allograft (AL) plus local autograft or local autograft only (AT) was used. The cost of 30 mL of allograft bone at the completion of this study was $404.00 per case.

A total of 657 patients (80.2% female) with a mean follow-up of 32.5 months were included. Overall, 415 were treated with AL and 242 with AT. There were no differences in the rate of pseudoarthrosis between groups [AL: 1.2% (n=5) vs. AT: 2% (n=5), P=0.384]. The percentage of patients not developing pseudoarthrosis was 93.1% and 95% at 105 months for AL and AT, respectively (P=0.596). The development of pseudoarthrosis was not affected by the type of graft used (HZ: 3.04; 95% CI: 0.65-14.12).

PSF for AIS achieves high fusion rates exceeding 90% survivorship free of pseudoarthrosis at 9 years postoperatively, regardless of whether local AT or AL are utilized. Importantly, the use of AT alone showed no inferiority compared with AL suggesting that may be sufficient for achieving successful fusion.

Level III.