Spine Surgeon NYU School of Medicine New Canaan, CT, US
Introduction: Despite reports showing positive long-term functional outcomes following adult spinal deformity (ASD) corrective surgery, it is still unclear which factors define best outcomes and how they correlate to postoperative complications.
Methods: ASD surgical patients with available baseline (BL) radiographs, and 1-year postop (1Y) radiographs for patients who met substantial clinical benefit threshold (SCB, < 31.3 points), had no PJF, or reoperation for a mechanical failure by 1Y were included. Patient cohorts were: those who sustained ODI at SCB threshold with no PJK or mechanical failure with reoperation beyond 1Y postop (sustained functionality), and those who did not (functional deterioration). Means comparison tests assessed differences in patient-related, surgical variables, and complications between cohorts.
Results: 438 surgical ASD patients were included and all sustained functionality at 1Y postop. Despite no differences in BL sex, BMI, levels fused, LOS, EBL and optime between sustained vs. deteriorated durability cohorts, those who sustained after 1Y had significantly different BL age (52.1 years vs 62.0, P< 0.001), CCI (0.89 vs 1.64, P< 0.001) and mFI (3.0 vs 6.1, P< 0.001). Sustained functionality patients were less likely to experience any complication (36.5% vs 71.9%; p< 0.001), major complication (13.5% vs. 32.8%; p=0.003), and any reoperation (1.9% vs. 26.6%; p< 0.001). Adjusting for age, mFI, and invasiveness, functional durability patients were less likely to experience any complication (OR: 0.141, 95% CI: [0.045 – 0.443]; p=0.001) and any reoperation (OR: 0.030, 95% CI: [0.005 – 0.183]; p< 0.001).
Conclusion : Regression analysis determined predictors of functional durability: LIV, CCI, Frailty, lack of a decompression, VCR or 3CO, a number of baseline radiographic variables [SS, PT, TK, CL, SVA, TPA, CPA, GT] and HRQLs [PCS, NDI, SRS Total, EQ5D]. Multivariate regression and ROC curve including these predictors and controlling for baseline age, sex, levels fused, and ODI resulted in an AUC of 85.0%.
