General Session: Value and Outcomes in Spine Surgery

Presented by: S. Koutsoumbelis - View Audio/Video Presentation (Members Only)


P. Schadler(1), P. Derman(1), J. Shue(1), S. Koutsoumbelis(1), L. Lee(1), H. Do(1), A.A. Sama(1), F.P. Girardi(1), F.P. Cammisa(1), A.P. Hughes(1)

(1) Hospital for Special Surgery, New York, NY, United States


Summary of Background Data: The economic burden of spine-related health care in the United States has been estimated at $100 billion dollars annually and a 65% increase in spine-related health care medical expenditures from 1997 to 2005 was reported. This emphasizes the importance of economic evaluation of surgical procedures. With an increasing system-wide focus on value-based health care, the goal of economic evaluation is to identify high quality of care which minimizes costs. Few studies have compared the costs of different approaches for lumbar fusion surgery.

Objective: The purpose of this study was to compare the costs of single-level lumbar fusion, performed as (1) posterior instrumented fusion alone (PSF), (2) posterior interbody fusion with posterior instrumentation (PLIF), or (3) minimally invasive lateral interbody fusion with posterior instrumentation (MILIF), over a period of 6 years.

Study Design: Retrospective chart review with telephone follow-up

Methods: Patient charts were retrospectively reviewed for demographic and surgical details. Patients were followed up with a telephone questionnaire to obtain information on reoperation status and satisfaction. In order to perform cost estimation from the payer's perspective, the average surgery-related Medicare reimbursement was calculated for the three treatment groups for index procedures (PSF-$34,432, PLIF-$36,605, MILIF-$52,879) and reoperations (PSF-$35,098, PLIF-$29,292, MILIF-$43,870) as cost estimates. Using rates published previously, the mean cost for epidural injections per patient was estimated ($2,864). Bivariate analysis was used for assessment of associations. Survival analysis (Kaplan-Meier and multivariate Cox regression analysis) was performed to assess the time to elevated resource use (defined as greater than 90% of patients in this study or $68,672). Multivariate logistic regression analysis was performed to assess overall satisfaction.

Results: A total of 337 patients, 45, 222 and 70 in the PSF, PLIF and MILIF groups respectively, were included. Overall follow-up rate was 63% at 6 years. PSF patients were significantly older (PSF-72±12 vs PLIF-59±13 vs MILIF-65±10 years, p< 0.001). Surgical time was lowest in the PSF group (p< 0.001), while blood loss was lowest in the MILIF group (p< 0.001) at index procedure. The length of stay after the index procedure was not significantly different among groups (p=0.369). Kaplan-Meier analysis showed that PLIF patients were less likely to reach the cut-off compared to PSF (p=0.002) and MILIF (p=0.006) at an average follow-up of 6 years. Multivariate Cox regression analysis showed that PSF patients and MILIF patients were 3.3 and 3.4 times more likely to reach the elevated resource use cut-off (PSF-HR 3.280, p=0.017, MILIF-HR 3.370, p=0.017). Multivariate logistic regression showed that MILIF patients were 3.3 times more likely to be satisfied compared to PLIF patients (OR 3.320, p=0.002).

Conclusion: Multivariate Cox regression analysis showed that patients undergoing MILIF or PSF were more likely to have higher resource utilization than those undergoing PLIF and thus incur greater costs to payers at an average follow-up of 6 years. The high cost estimate for procedures in the MILIF group and for reoperations for PSF patients led to greater costs compared to the PLIF group. Multivariate logistic regression demonstrated that patients in the MILIF group were more likely to be satisfied with the overall result of their surgery, compared to PLIF patients.