Perseverance of Optimal Realignment is Associated With Improved Cost-utility in Adult Cervical Deformity Surgery

Background: Early-term complications may not predict long-term success after adult cervical deformity (ACD) correction. Objective: Evaluate whether optimal realignment results in similar rates of perioperative complications but achieves longer-term cost-utility. Study Design: Retrospective cohort study. Methods: ACD patients with 2-year data included. Outcomes: distal junctional failure (DJF), good clinical outcome (GCO):[Meeting 2 of 3: (1) NDI>20 or meeting MCID, (2) mJOA >= 14, (3)NRS-Neck improved >= 2]. Ideal Outcome defined as GCO without DJF or reoperation. Patient groups were stratified by correction to 'Optimal radiographic outcome', defined by cSVA 9 (<40 mm) AND TS-CL (<15 deg) upon correction. Cost calculated by CMS.com definitions, and cost-per-QALY was calculated by converting NDI to SF-6D. Multivariable analysis controlling for age, baseline T1-slope, cSVA, disability, and frailty, was used to assess complication rates, clinical outcomes, and cost-utility based on meeting optimal radiographic outcome. Results: One hundred forty-six patients included: 52 optimal radiographic realignment (O) and 94 not optimal (NO). NO group presented with higher cSVA and T1-slope. Adjusted analysis showed O group suffered similar 90-day complications (P>0.8), but less DJK, DJF (0% vs. 18%; P<0.001) and reoperations (18% vs. 35%; P=0.02). Patients meeting optimal radiographic criteria more often met Ideal outcome [odds ratio: 2.2, (1.1-4.8); P=0.03]. Despite no differences in overall cost, O group saw greater clinical improvement, translating to a better cost-utility [mean difference: $91,000, ($49,000-$132,000); P<0.001]. Conclusion: Despite similar perioperative courses, patients optimally realigned experienced less junctional failure, leading to better cost-utility compared with those sub-optimally realigned. Perioperative complication risk should not necessarily preclude optimal surgical intervention, and policy efforts might better focus on long-term outcome measures in adult cervical deformity surgery.