Wednesday, September 26, 2018 2:00 PM – 3:00 PM Increasing Value: Lumbar Spine Surgery: 65. Cost-effectiveness of vancomycin powder in lumbar laminectomy

BACKGROUND CONTEXT Intra-wound application of vancomycin powder has demonstrated dramatic reductions of infection rate following lumbar laminectomy and fusion. The economic benefit of this prophylactic protocol has been previously validated for laminectomy and fusion, but the cost-effectiveness is less clear for lumbar laminectomy alone. PURPOSE The goal of this study is to demonstrate that application of vancomycin powder is a cost-effective method for preventing infection following lumbar laminectomy. STUDY DESIGN/SETTING Break-even cost analysis. OUTCOME MEASURES This study determined the magnitude by which the rate of infection following lumbar laminectomy alone and lumbar laminectomy and fusion would need to be reduced by in order to make application of vancomycin powder cost effective. METHODS The product cost of vancomycin powder was obtained from our institution's purchasing records. Total charges for lumbar laminectomy and lumbar laminectomy and fusion, rates of infection, and cost of revision were obtained from the literature. A break-even analysis [break-even infection rate=(initial infection rate−cost of protocol)/cost of treatment] was then performed to determine the absolute risk reduction (ARR) in infection rate to make prophylactic application of vancomycin powder cost effective. RESULTS Costing $3.06 per gram at our institution, vancomycin powder was determined to be cost-effective in lumbar laminectomy if the infection rates of 4.2% decreased by an ARR of 0.015%. Laminectomy and fusion was also determined to be cost effective at the same cost of vancomycin powder if the infection rate of 8.5% decreased by an ARR of 0.0034%. At the current highest cost reported in the literature, $44.00 per gram of vancomycin powder remained cost-effective with respective ARRs of 0.21% and 0.048% for laminectomy and laminectomy and fusion. Varying the baseline infection rate did not influence the ARR for either procedure when the analysis was performed using the product cost of vancomycin at our institution. CONCLUSIONS This break-even analysis demonstrates that prophylactic intra-wound application of vancomycin powder can be highly cost effective not only for lumbar laminectomy and fusion, but also for laminectomy alone. At our institution's price point, use of vancomycin powder is economically justified if it prevents at least one infection out of 6,700 lumbar laminectomy surgeries. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.