Introduction: Despite its benefits to health outcomes, lumbar fusion is associated with substantial costs. This study analyzed the cost effectiveness of instrumented fusion for Grade I L4-L5 spondylolisthesis.

Methods: Four cohorts of 25 patients with Grade I L4-L5 degenerative spondylolisthesis were analyzed: Cohort 1, decompression without instrumented fusion; Cohort 2, decompression with instrumented posterolateral fusion (PLF); Cohort 3, decompression with instrumented posterior lumbar interbody fusion/transforaminal lumbar interbody fusion (PLIF/TLIF); and Cohort 4, decompression with instrumented PLF and PLIF/TLIF where instrumentation signifies pedicle screw fixation. Direct medical costs were estimated using Medicare national payment amounts, health resource utilization was recorded from patient electronic medical records, and indirect costs were based on patient missed work days. Postoperative 1-year cost/utility ratios were calculated as total cost/change in quality adjusted life year (?QALY) from pre-op to post-op. Incremental cost effectiveness ratios (ICERs) were also calculated. Cost effectiveness was assessed using a threshold of $100,000/QALY gained.

Results: Compared with preoperative health states, QALY scores improved for all cohorts (p<0.0001). The one-year cost-utility ratio for Cohort 1 was significantly lower ($56,610/QALY gained; p<0.0001) than that for Cohorts 2 ($116,991.09/QALY gained), 3 ($109,739.61/QALY gained), and 4 ($107,546.20/QALY gained). The one-year ICER for cohort 1 was dominant compared to all other cohorts (i.e., negative ICERs are not reported).

Conclusions: Decompression without fusion is cost effective for patients with Grade I L4-L5 spondylolisthesis. Decompression with instrumented PLF, with PLIF/TLIF, and with PLF and PLIF/TLIF are not cost effective in a 1-year timeframe for these patients based on the threshold of $100,000. There were significant improvements in quality of life measures (QALY) across all cohorts in the 1-year postoperative period above the 1-year minimum clinically important difference (MCID), showing that surgical intervention is beneficial to patients with spondylolisthesis. Accordingly, while fusion is beneficial for improving health outcomes in patients with spondylolisthesis, it is not cost effective in a 1-year timeframe.

Patient Care: As healthcare costs continue to rise, it is imperative that healthcare outcomes remain in line with the costs spent in the healthcare system. In 2009, the United States spent 16% of its gross domestic product (GDP) on healthcare services – a cost high enough to achieve a rank of 2nd by the World Health Organization (WHO) among all countries in annual healthcare spending. Yet, the WHO ranks the U.S. 37th out of 191 countries relative to the quality of its healthcare system. An increasing focus on healthcare costs has spurred interest in analyzing long term economic analysis of surgical procedures through comparative effectiveness research. This has been true of many fields, including spine surgery. Cost-effectiveness analysis (CEA) is a component of comparative effectiveness research (CER) that estimates the value of a healthcare intervention by not only comparing treatments based on quality of life gained, but also on the financial burden of the different treatments to the patient. A cost-utility analysis (CUA) is a specific type of CEA whereby the benefit of the intervention is expressed as a utility measure numerically chosen by the patient. A CUA also provides data that can be used to compare one intervention in one specific field of medicine (e.g., spine surgery) to other disciplines of medicine (e.g., cardiology). Rising costs associated with spinal fusion procedures, as well an increasing number of patients undergoing fusion and varying results of effectiveness, warrant intensive cost-utility analyses in the spine field. Cost-utility and incremental cost effectiveness ratios derived from CUAs can be used to better allocate healthcare resources and reduce the economic burden to both the patient and the healthcare institution in the future. Our research seeks to focus on calculating these ratios for common surgical procedures in the spine field in order to aid the spine surgeon or neurosurgeon in determining the most cost effective option for his or her patient population.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of cost effectiveness research in surgical procedures and 2) Understand cost/utility ratios and incremental cost effectiveness ratios

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