P102. Determining the impact of proximal junctional kyphosis on cost utility in adult spinal deformity patients

BACKGROUND CONTEXT With health care costs on the rise, hospitals have increasingly focused on providing economically efficient medical services. Adult spinal deformity surgery remains an expensive medical intervention with high risk for complications and revisions, especially following mechanical failure in the context of proximal junctional kyphosis (PJK). We sought to evaluate the impact of PJK on associated expenditures following an index surgery for ASD. PURPOSE To evaluate the effect of proximal junctional kyphosis on the cost effectiveness of corrective adult deformity surgery. STUDY DESIGN/SETTING Retrospective cohort study of a prospective single-center database of ASD patients. PATIENT SAMPLE A total of 147 Adult Spinal Deformity Patients. OUTCOME MEASURES Complications, HRQLs (Oswentry Disability Index [ODI]), Quality adjusted life years (QALY). METHODS Adult Spinal deformity patients with 2-year HRQL follow-up were included. Utility data was calculated using published conversion methods to convert ODI to SF-6D. QALYs utilized a 3% discount rate to account for residual decline to life expectancy (78.7 years). Costs were calculated using the PearlDiver database incorporating complications and comorbidities classified according to CMS standard definitions. Reimbursement consisted of a standardized estimate using regression analysis of Medicare pay-scales for all services rendered within a 30-day window, including estimates regarding costs of postoperative complications, outpatient health care encounters, reoperations and revisions. After accounting for all postoperative events, including mortality, cost per QALY by 2Y was calculated for revisions that occurred due to proximal junctional kyphosis. RESULTS A total of 147 adult spinal deformity patients met inclusion criteria (55.22years, 54% Female). At baseline, patients presented radiographically as: Pelvic Tilt (23.66±11.7), Pelvic Incidence- Lumbar Lordosis (-2.9±12.6), Sagittal Vertical Axis (60.5±76.8), T1 Pelvic Angle (22.6±14.3). Surgical details: EBL of 1823 mL, operative time of 327 min, with .4% undergoing an anterior approach, 90.2% posterior-only approach, and 9.3% combined approach. Overall, 54.3% of patients developed PJK within 2 years postoperatively, with 22% undergoing reoperation for PJK. Average cost of revision surgery due to PJK was $93,688 ± $21,467. The cost for PJK patients, including the cost associated with their revision surgery, was higher ($103,760 vs $71,000). Baseline ODI (39 vs 32) and 2Y ODI (39 vs 27) were higher for PJK patients, however, PJK patients did improve to a greater degree (-12 vs -10). The overall cost per QALY by 2Y was higher for PJK patients ($116,170 vs $95,347). CONCLUSIONS Patients that developed PJK had an almost $30,000 higher initial cost at 2 years. When looking at the cost per quality adjusted life years by 2Y, PJK resulted in slightly more than $20,000 in cost. These findings suggest prophylactic measures to mitigate PJK may improve the cost utility of adult spinal deformity surgery and can help policy efforts for adequate resource allocation for these complex patients. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.