Purpose: To construct a cost-benefit model for intraoperative neurophysiological monitoring (IOM) in spinal surgeries.
Methods: Decision model was based on sensitivity, specificity, IOM cost, prevention rate given an IOM alert, and spinal procedure neurologic complication rates in pooled estimates from the published literature with outcome of lifetime costs after neuromonitored versus unmonitored spinal surgeries. Lifetime cost of neurologic injury was the sum of direct health care costs and lost wages and benefits. Results from Monte Carlo simulation with 10,000 replications were analyzed for cost outcomes and relationship of input variables to outcomes.
Results: IOM saved $23,189 (P < 0.001) for the reference case of 50-year-olds with neurologic complication rate of 5%, 2009 Medicare reimbursement of IOM at $1,535 per operation, 52.4% prevention rate given an IOM alert at 94.3% sensitivity and 95.6% specificity, assuming incomplete (nonplegic) motor injury. The baseline risk of surgery, lifetime costs after neurologic deficit, and ability to prevent neurologic deficits after an IOM alert were most correlated with cost outcomes. In linear prediction models, IOM remained cost-saving when neurologic complication rate from surgery exceeded 0.3% (P < 0.001) and prevention rate after IOM alert was greater than 14.2%(P = 0.02).
Conclusions: Intraoperative monitoring is cost-saving for spinal surgeries in a theoretical model based on the current published literature.