A Risk Quantification Reference Table for Progressed Adolescent Idiopathic Scoliosis Surgery: An Exact Case Matched Outcomes Analysis

STUDY DESIGN: Retrospective Exact Matched case-control study OBJECTIVES: Surgical treatment delay in AIS due to family preferences is common. This study aims to quantify the increase in risks as the Cobb angle increases and provide a Quantifiable Risk Reference Table that can be utilized for counseling. METHODOLOGY: AIS patients were divided into 3 groups: Group A: Cobb angle 50–60°, Group 61–70°, and Group C(Final) ≥80°. Each patient in Group C(Final) who had curve progression were then traced-back-in-time (TBIT) to review the clinical data at earlier presentations at 50–60° (C(1)), and 61–70° (C(2)). Patient demographics, radiological, operative, and outcomes data were compared between Group A vs C(1) and Group B vs Group C(2). RESULTS: A total of 614 AIS surgeries were reviewed. Utilizing the EM technique, a total of 302 AIS patients were recruited. There were 147, 111, 31, and 32 patients matched in Groups A, B, C(1,) and C(2), respectively. C(2 Final) patients had 34% curve pattern change, 23.2% higher incidence of requiring two surgeries, and 17.3% increase in complications. There was a statistically significant increase of 2.4 spinal levels fused, 12% increase in implant density, 35% increase in operative time, 97% increase in intra-operative blood loss, 10% loss of scoliosis correction, 40% longer hospitalization stay, and 36% increase in costs for patients who had curve progression. CONCLUSION: This study is the first to use a homogenously matched AIS cohort to provide a Quantifiable Risk Reference Table. The Risk Table provides essential knowledge for treating physicians when counseling AIS patients.