Abstract
Introduction
Spinal deformities affect 3–50% of the population, with the number of spinal fusions performed in the USA rising each year. After undergoing surgical management for adult spinal deformity, 9–19% of patients may require revision procedures for failure of bony fusion, implant complications, refractory pain, and deformity progression. Rising healthcare costs, and a focus shift to achieving significantly better health outcomes per dollar spent, have led to increasing interest in determining the value of complex spine surgeries. Despite mounting scrutiny of increasing costs, data evaluating cost effectiveness of primary and revision surgery for adult spinal deformity (ASD) is sparse. Investigation is particularly needed in the revision surgery population, where complication rates may be higher. In this regard, our goal was to assess the functional outcomes, two-year comprehensive costs, and cost effectiveness of primary and revision arthrodesis for ASD.
Material and Methods
We retrospectively reviewed 119 consecutive patients who had undergone primary (fifty-six patients) or revision surgery (sixty-three patients) for ASD, with > five levels fused at their index surgery, and who were followed for a minimum of two years. Two-year total spine-related medical resource utilization was confirmed via retrospective analysis of hospital records. Costs were derived from data maintained within our institution's finance sector, and reflected the hospital perspective. Functional outcome scores were extracted from prospectively collected patient data. QALY units were derived from SF-36 scores mapped to EQ-5D. Cost effectiveness was assessed using a threshold of $159,126/QALY gained, three times the US per capita GDP in 2013.
Results
Both the primary surgery cohort (n = 56: 41F, 15M) and the revision cohort (n = 63: 48 F, 15M) demonstrated statistically significant improvement in health related quality of life scores at two years. Median surgical and follow-up costs over two years were $137,990 for primary surgery versus $115,509 for revision surgery, and were not significantly different between the two groups (p = 0.12). We report a two-year QALY gain of 0.36 (IQR 0.01-.62) in the primary surgery cohort, versus 0.40 (IQR 0.01-.80) in the revision group (p = 0.71). Primary instrumented arthrodesis was associated with a two-year cost per QALY of $197,809 versus $129,950 for revision surgery (p = 0.31).
Conclusion
We found that revision surgery for ASD had a lower two year total cost, and higher two year QALY gains than primary surgery, though not significant. While revision surgery for spinal deformity in adults is known to be technically challenging and may have a higher rate of complications than primary surgery, revision surgery was more cost effective than primary surgery at two years. A history of failed spinal surgical procedures should not by themselves be considered to render future reconstructive procedures non-cost-effective. To our knowledge, this is the first description of the cost effectiveness of revision surgery for ASD, as well as the first for primary surgery utilizing two year spine care-related cost data from a hospital perspective.