Three-year Outcomes from a Multicenter, European Real-world Study Assessing Patients Using Fast-acting Sub-perception Therapy (FAST)

Introduction: Conventional spinal cord stimulation (SCS) techniques that produce analgesia without perceptible sensation—such as those operating at ~1–10 kHz or using burst patterns—typically require 24 to 48 hours to reach full therapeutic effect. In contrast, an identified approach known as Fast-Acting Sub-Perception Therapy (FAST) utilizes surround inhibition to achieve pain relief within minutes of initiation (1). This rapid response can enable clinicians to verify therapy success during the same clinic visit. Here, we report 2-year outcomes of real-world patients who preferred FAST-SCS for chronic pain in a European-based, multicenter, observational study.

Methods: This is an international, multicenter, observational case-series of patients permanently implanted with a FAST­-enabled SCS system (Boston Scientific, Marlborough, MA USA) to treat chronic pain as part of an ongoing assessment of real-world outcomes of SCS for chronic pain based on retrospective chart review (Clinicaltrials.gov identifier: NCT01550575). All analyzed patients were programmed using novel FAST (i.e., biphasic-symmetric waveform at 90 Hz; pulse width: 160-260 µs). Demographic information, pain location, surgical history, medical history were collected for all subjects. In addition, Numeric Rating Scale (NRS) scores, Percent Pain Relief (PPR), Oswestry Disability Index (ODI) scores, and EQ-5D-5L scores were collected as part of the chart review.

Results: To date, 167 patients who reported preferred FAST-SCS have been assessed out to a mean follow-up duration of 1.6 ± 1.4 years. The mean baseline NRS pain score in this current cohort was determined to be 8.0 ± 1.2. The responder rate (i.e., proportion of those reporting ≥50% pain relief) at last mean follow-up was 87% (n =100). Significant reduction in pain (mean 5.5-point NRS pain score decrease versus baseline; n =126), and improvement in disability (29-point reduction in ODI score; n = 65) were also observed in patients assessed at last mean follow-up. In those patients evaluated at 24-months follow-up (n = 52), a mean 5.6-point NRS overall pain score reduction was observed (p < 0.0001), and 67% had an NRS pain score of ≤2.

Conclusion: A methodology that allows for near immediate pain relief following activation of neurostimulative treatment represents an advancement that may further improve the outcomes and experience of patients who desire to use sub-perception-based SCS for relief of their chronic pain. Furthermore, these real-world findings demonstrate that by engaging the surround inhibition mechanism, FAST represents a novel, fast-acting, and personalized sub-perception approach for effective and efficient SCS in patients with chronic pain. These results need to be confirmed with further evidence from large, prospective, long-term trials.