86. Long-term cost-effectiveness of full endoscopic vs open discectomy: two-year results of a RCT

Abstract

<h3>BACKGROUND CONTEXT</h3> Open microdiscectomy is a frequently performed surgical procedure for sciatica caused by lumbar disc herniation. Percutaneous transforaminal endoscopic discectomy (PTED) has been introduced as a less invasive alternative and 1-year results show non-inferiority in leg pain reduction and dominancy in cost-effectiveness. <h3>PURPOSE</h3> To compare the long-term cost-effectiveness of PTED with open microdiscectomy among patients with sciatica caused by lumbar disc herniation as measured at two years. <h3>STUDY DESIGN/SETTING</h3> Randomized controlled trial at four clinics in the Netherlands which ran from February 2016 to April 2019. <h3>PATIENT SAMPLE</h3> Patients were aged from 18 to 70 years and had at least 6 weeks of radiating leg pain caused by lumbar disc herniation. The trial included a predetermined set of 125 PTED patients who were the early cases performed by three surgeons who had not performed PTED before the trial. Eventually 304 patients were allocated to PTED and 309 to open microdiscectomy. <h3>OUTCOME MEASURES</h3> Primary effect measures included leg pain as measured on the VAS for leg pain and health-related quality of life (QALYs). Costs were measured from a societal perspective. <h3>METHODS</h3> An economic evaluation was conducted alongside the PTED trial. A cost-effectiveness analysis and a cost-utility analysis were conducted. The primary analysis was conducted according to the intention-to-treat approach. All missing data were imputed using multiple imputation by chained equations (MICE), stratified by treatment group. Predictive mean matching was used to create 10 complete datasets. Disaggregate cost differences were analyzed using linear regression models, both adjusted and unadjusted for confounders. Differences in total costs and effects between treatment groups were obtained from a system of seemingly unrelated regressions (SUR) that accounted for the potential correlation between costs and effects. These total cost and effect differences were adjusted for baseline and confounders. Incremental cost-effectiveness ratios were calculated by dividing incremental costs by incremental effects. Uncertainty was estimated by bootstrapping and presented using Cost-effectiveness Planes and Cost-Effectiveness Acceptability Curves. <h3>RESULTS</h3> At 24 months, 92% of the follow-up data were available. Statistically significant differences in leg pain and QALYs were found in favor of PTED at 24-month follow-up (leg pain: 7.3; QALYs: 0.043). Surgery costs were higher for PTED than for open microdiscectomy (ie, €4,500/patient vs €4,095/patient). All other disaggregate costs as well as total societal costs were lower for PTED than for open microdiscectomy, namely primary care, secondary care, medication, informal care, absenteeism, presenteeism and productivity loss. Per performed PTED procedure, €138 in health care costs and €2787 in societal costs are saved. Cost-effectiveness acceptability curves indicated that the probability of PTED being cost-effective compared with open microdiscectomy (meaning on average less costly and more effective) was 99.4% for leg pain and 99.2% for QALYs, regardless of the willingness-to-pay. <h3>CONCLUSIONS</h3> Results suggest that PTED is less costly and more effective, and therefore cost-effective compared with microdiscectomy for patients with sciatica from the societal perspective. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.