High-Dose Spinal Cord Stimulation Reduces Long-Term Pain Medication Use in Patients With Failed Back Surgery Syndrome Who Obtained at Least 50% Pain Intensity and Medication Reduction During a Trial Period: A Registry-Based Cohort Study

Abstract

Objectives: High-dose spinal cord stimulation (HD-SCS) revealed positive results for obtaining pain relief in patients with failed back surgery syndrome (FBSS). However, it is less clear whether HD-SCS also is able to reduce pain medication use. The aim of this registry-based cohort study is to explore the impact of HD-SCS on pain medication use in FBSS patients.

Materials and methods: Data from the Discover registry was used in which the effectiveness of HD-SCS was explored in neurostimulation-naïve FBSS patients as well as in rescue patients. All neurostimulation-naïve FBSS patients positively responded to a four-week SCS trial period in which at least 50% pain relief and 50% medication reduction were obtained. Medication use was measured with the Medication Quantification Scale III (MQS) in 259 patients at baseline and at 1, 3, and 12 months of HD-SCS. Additionally, defined daily doses (DDD) and morphine milligram equivalents (MME) were calculated as well.

Results: One hundred thirty patients reached the visit at 12 months. In neurostimulation-naïve patients, a statistically significant decrease in MQS (χ² = 62.92, p < 0.001), DDD (χ² = 11.47, p = 0.009), and MME (χ² = 21.55, p < 0.001) was found. In rescue patients, no statistically significant improvements were found. In both patient groups, statistically significant reductions in the proportion of patients on high-risk MME doses ≥90 were found over time. At the intraindividual level, positive correlations were found between MSQ scores and pain intensity for back (r = 0.56, r = 0.31, p < 0.001) and leg pain (r = 0.61, r = 0.22, p < 0.001) in neurostimulation-naïve and rescue patients, respectively.

Conclusions: Registry data on HD-SCS in FBSS patients revealed a statistically significant and sustained decrease in pain medication use, not only on opioids, but also on anti-neuropathic agents in neurostimulation-naïve patients, who positively responded to an SCS trial period with at least 50% pain relief and 50% pain medication decrease, but not in rescue patients.

Keywords: High-dose spinal cord stimulation; medication; opioids; registry-based cohort study.