Director of Spinal Deformities Program Hoag Spine Institute Irvine, United States
Disclosure(s):
Peter G. Passias, MD: Cerapedics: Consultant (Ongoing); Globus Medical: Consultant (Ongoing); Journal of Neurosurgery: Spine: Board Member/Officer/Trustee (Ongoing); Medtronic: Consultant (Ongoing); Nuvasive: Consultant (Ongoing); Royal Biologics: Consultant (Ongoing); Spine: Board Member/Officer/Trustee (Ongoing); Terumo: Consultant (Ongoing)
Introduction: Several systems have been developed to classify thoracolumbar alignment in adult spinal deformity (ASD). However, the cost effectiveness of meeting additional alignment criteria has yet to be explored. This study aims to quantify and compare cost effectiveness of meeting additional alignment criteria
Methods: Retrospective study of a single-center ASD database. ASD patients with baseline(BL) and 2 year(2Y) data were included. Patients were assessed by 4 published alignment systems: SRS-Schwab, GAP Score, Age-Adjusted(AA), and Roussouly(Rous). Patients were separated into 5 groups by number of systems(0 – 4) met at 2Y and cost utility was calculated for each group. Multivariate analysis(MVA) assessed differences in outcomes of interest. Cost analysis was based on average DRG reimbursement and QALY analysis used ODI converted to SF-6D using published methods, with a 3% discount applied for residual decline to life expectancy(LE).
Results: 364 patients met inclusion (58.9±14.6yrs, 81.5% Female, 26.9±5.4kg/m2). Of these, 15 patients met 0 (0/4), 61-met only 1 (1/4), 129-met any two (2/4), 126-met any 3 (3/4), and 33-met all 4 alignment systems. There were no significant differences in demographics between groups, p>.05. Compared to those who met 0 criteria, only patients who met 1/4 had significantly lower rates of complications and significantly lower 2Y costs(both p < .01). MVA found those meeting 0 criteria had the lowest QALYs gained at 2Y (0.12) and highest Cost/QALY at 2Y ($733,038/QALY) p < .05. In contrast, patients aligned to 1/4 criteria had highest QALYs gained at 2Y (0.22) and lowest Cost/QALY at 2Y ($317,602), p < .05.
Conclusion : ASD patients corrected to one alignment system had lower complication rates, lowest 2Y cost, highest QALYs gained and lowest cost/QALY at 2Y and LE. These data suggest that while maximal cost effectiveness may be achieved without realign alignment to more than one classification schema, realignment to ≥1 system is essential for achieving cost utility in ASD surgery.
