Availability of Greater Resources at Time of Surgery Allows for Improved Outcome in Adult Spinal Deformity Surgery

Introduction: Patients with less severe ASD undergo surgical correction and often achieve good clinical outcomes. However, it is not well understood how increasing utilization of surgical cost in the perioperative period can influence outcomes.

Methods: Operative ASD patients with up to 2Y data included. Perioperative resources: length of stay, SICU stay, discharge to rehabilitation center, readmission rates in 90days. Patients stratified by resource utilization and total cost: Highest quartile as High Utilizer(HU), lowest quartile as Low Utilizer(LU). Cost data based on average Medicare reimbursement by DRG, standardized for New York State. Utility calculated using ODI converted to SF-6D based on published methods. Utility assessed cost/QALY at 2Y. ANCOVA and logistic regressions accounting for surgical invasiveness assessed differences in outcomes, including complications and Schwab deformity.

Results: 469 included(59.9±14.7yrs, 27.3±5.3kg/m2, CCI: 1.63±1.6, FI: 3.12±1.65). 154 HU patients, 201 LU patients. HU had a higher mean BMI, more often male(both p<.001), and had a higher CCI(4.4 vs. 3.1, p=.019), with greater osteotomies(53% vs 12%) and surgical invasiveness score(32.5 vs 12.7,all p<.05). HU had an average cost of $49,274 vs $21,279 for LU(p <.05). The greatest predictive factor for HU was readmission within 90d(OR: 2.03, [0.014, 0.106], p<.001) and reoperation(OR: 3.677, [0.487, 0.942], p=.021). By 2Y, HU had higher odds of reaching SCB in ODI(OR: 2.356, p=.011) and in SRS-Total(OR: 2.988, p=.002), and higher odds of reaching SCB in NRS Back(OR: 2.739, [1.105, 6.788], p=.030). HU had greater odds of less deformity by 2Y: 5.2x higher odds of “0” SVA Schwab(OR: 5.245, p<.001), 2.7x higher odds of “0” PI-LL(OR: 2.714, p=.011), 2.2x higher odds of “0” PT(OR: 2.238, p=.013). LU had significantly lower rates of SICU stay(OR: 0.293, p=.039) and higher baseline frailty scores(4.2 vs. 2.9, p=.02). HU had significantly lower EBL(1614mL vs. 2697mL, p=.027).

Conclusion : HU experienced superior patient-reported outcomes by 2 years compared to LU. While cost efficiency remains an important priority for health policy, cost reduction in perioperative course may add to future costs of re-intervention, particularly with more severe baseline deformity.