Pseudoarthrosis After Posterior Spinal Fusion in Adolescent Idiopathic Scoliosis: A Multicenter Analysis of Revision Strategies and Outcomes.

Abstract

Retrospective analysis of a prospectively maintained multicenter pediatric spine registry. To characterize clinical presentation, revision strategies, bone graft utilization, and short-term outcomes in adolescent idiopathic scoliosis (AIS) patients undergoing revision for pseudoarthrosis. 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. 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. 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. 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. Level IV.