Pseudoarthrosis After Posterior Spinal Fusion in Adolescent Idiopathic Scoliosis

Study Design: Retrospective analysis of a prospectively maintained multicenter pediatric spine registry. Objective: To characterize clinical presentation, revision strategies, bone graft utilization, and short-term outcomes in adolescent idiopathic scoliosis (AIS) patients undergoing revision for pseudoarthrosis. Summary of Background Data: Pseudoarthrosis following posterior spinal fusion (PSF) for AIS is rare but clinically significant, often presenting with pain or implant failure. Contemporary, diagnosis-specific data describing revision strategies and outcomes remain limited. Methods: A multicenter registry was queried for AIS patients undergoing PSF with ≥2 years follow-up. Potential pseudoarthrosis cases were identified using complication codes and confirmed through review of radiographs, operative reports, and clinical documentation, defined as failed arthrodesis >6 months post-index fusion, excluding infection. Demographics, revision techniques, graft selection, and outcomes were analyzed descriptively. Results: Among 3,532 eligible AIS patients, 22 had confirmed pseudoarthrosis requiring revision. Median time to revision was 2.5 years. Twelve patients (55%) presented with pain and 10 (45%) were identified radiographically. Implant failure most commonly involved the distal construct (17/22, 77%), with screw loosening in 9 (41%), rod fracture in 7 (32%), and screw breakage in 6 (27%). All revisions were posterior-only; 16 patients (73%) preserved index fusion levels and 5 (23%) required extension for junctional deformity. Revision was tailored to failure patterns, including focal screw revision and rod exchange, with partial rod revision used in 8 of 18 rod failures (44%). Graft use was heterogeneous, most commonly allograft (68%) and local autograft (46%). Post-revision complications occurred in 2 patients (9%), both surgical site infections, with one reoperation (5%). At median 1.2-year follow-up, no recurrent pseudoarthrosis was observed. Conclusion: Pseudoarthrosis after AIS PSF most commonly presents as distal mechanical failure. Posterior-only, failure-pattern–directed revision, typically preserving fusion levels with selective extension for junctional deformity, achieves favorable short-term outcomes. These findings provide multicenter, diagnosis-specific guidance for management of this rare complication.