Introduction

Spinal Cord Stimulation (SCS) as a treatment for chronic pain has been historically designated for patients who have had at least one prior spinal surgery. Considering the opioid crisis, and the often-mixed clinical success of conservative treatment approaches and invasive back surgery procedures, there is growing interest in utilizing SCS in chronic pain patients who have not yet undergone previous surgical intervention.^1-4 Recent SCS devices offer substantially more novel technological or neurostimulative capabilities than older-generational SCS systems. Correspondingly, interventional treatment approaches capable of multimodal therapeutic strategies are now actively recommended by pain care advocates.^5,6

Materials / Methods

This is a prospective, multicenter randomized, controlled study (SOLIS) that compares SCS (Wavewriter^TM SCS Systems, Boston Scientific, Valencia, CA, USA) versus Conventional Medical Management (CMM) in patients with chronic low back and/or leg pain with no prior spinal surgery (Clinicaltrials.gov: NCT04676022). Enrolled non-surgical back pain (NSBP) patients who met inclusion criteria were randomized to SCS versus CMM. Key inclusion criteria include diagnosis of chronic low back pain, with or without leg pain, for ≥6 months, and documented care of chronic pain for ≥90 days. The primary endpoint is responder rate (≥ 50% reduction in pain) with no increase in baseline opioid medications to treat pain at 3-months following treatment activation. Other secondary and/or exploratory measures include Quality-of-Life (SF-36; EQ-5D-5L), Disability (Oswestry Disability Index, ODI), and Safety Outcomes.

Results

The study successfully met its primary endpoint (p < 0.0001) and secondary endpoints based on a prespecified cohort of 60 treatment activated subjects. The primary endpoint analysis demonstrated that multimodal SCS combined with CMM was superior to CMM alone (p<0.0001) in treating NSBP patients at 3-months follow-up (SCS: 88% versus CMM: 8%). A 27-point reduction in ODI score (improvement in disability) was noted in the SCS group in comparison to a 6-point reduction in the CMM group. Ninety-two percent of subjects with SCS reported treatment satisfaction (i.e., much, or very much improved) at 3-months versus only 6% in the CMM group.

Discussion

Given the prevalence of non-surgical, refractory back pain and the increasing economic and societal burden it poses, providing SCS as an additional tool within the therapeutic armamentarium for chronic pain represents a key opportunity to address a clinically important need.

Conclusions

SCS with multiple modalities is effective in treating chronic pain in patients with no prior back surgery demonstrating superior outcomes compared with CMM. SOLIS RCT outcomes are consistent with those reported in a preceding RCT assessing patients diagnosed with currently-approved “on-label” chronic pain indications.⁷

References

1. Finnerup NB, Attal N, Haroutounian S, McNicol E, Baron R, Dworkin RH, Gilron I, Haanpää M, Hansson P, Jensen TS, Kamerman PR, Lund K, Moore A, Raja SN, Rice AS, Rowbotham M, Sena E, Siddall P, Smith BH, Wallace M. Pharmacotherapy for neuropathic pain in adults: a systematic review and meta-analysis. Lancet Neurol. 2015 Feb;14(2):162-73.

2. Al-Kaisy A, Van Buyten JP, Kapural L, Amirdelfan K, Gliner B, Caraway D, Subbaroyan J, Edgar D, Rotte A. 10 kHz spinal cord stimulation for the treatment of non-surgical refractory back pain: subanalysis of pooled data from two prospective studies. Anaesthesia. 2020 Jun;75(6):775-784.

3. Kapural L, Jameson J, Johnson C, Kloster D, Calodney A, Kosek P, Pilitsis J, Bendel M, Petersen E, Wu C, Cherry T, Lad SP, Yu C, Sayed D, Goree J, Lyons MK, Sack A, Bruce D, Rubenstein F, Province-Azalde R, Caraway D, Patel NP. Treatment of nonsurgical refractory back pain with high-frequency spinal cord stimulation at 10 kHz: 12-month results of a pragmatic, multicenter, randomized controlled trial. J Neurosurg Spine. 2022 Feb 11:1-12.

4. Kapural L, Calodney A. Retrospective Efficacy and Cost-Containment Assessment of 10 kHz Spinal Cord Stimulation (SCS) in Non-Surgical Refractory Back Pain Patients. J Pain Res. 2022 Nov 16;15:3589-3595.

5. U.S. Department of Health and Human Services, Alliance to Advance Comprehensive Integrative Pain Management (2019). Pain Management Best Practices Inter-Agency Task Force Report. https://painmanagementalliance.org/resources/hhs-report-2019/. Accessed October 28th, 2022.

6. Dowell D, Ragan KR, Jones CM, Baldwin GT, Chou R. CDC Clinical Practice Guideline for Prescribing Opioids for Pain - United States, 2022. MMWR Recomm Rep. 2022 Nov 4;71(3):1-95.

7. Wallace MS., et.al. Combination Therapy with Simultaneous Delivery of Spinal Cord Stimulation Modalities: COMBO Randomized Controlled Trial [Abstract]. NANS Annual Meeting, 2022.

Learning Objectives

1. To evaluate the use of SCS in the treatment of patients with non-surgical back pain (NSBP)

2. To compare pain relief outcomes of SCS versus Conventional Medical Management in a prospective randomized controlled trial for NSBP patients.

3, To compare quality-of-life outcomes of SCS versus Conventional Medical Management in a prospective randomized controlled trial for NSBP patients.

Introduction

Fast-Acting Sub-Perception Therapy (FAST) has demonstrated robust, profound pain relief with rapid (seconds to minutes) onset of analgesia in chronic pain patients implanted with Spinal Cord Stimulation (SCS) systems.¹ Initial results have been corroborated at other centers.² Sustained long-term improvement of up to 3 years has also been reported in an observational, real-world case-series.³ Recently published work suggests that FAST engages the surround inhibition mechanism of action, and computational modeling suggests that FAST activates dorsal column axons and inhibits dorsal horn projection neurons.⁴

Materials / Methods

The FAST study is a prospective, multi-center, single-arm study (with adaptive design) of patients implanted with SCS systems (WaveWriter^TM Systems, Boston Scientific, Valencia, CA, USA) for chronic pain. The primary endpoint is based on the targeted pain responder rate (≥50% reduction) 3-months post-activation with no increase in average daily opioid medications. Secondary endpoints include (but are not limited to) patient satisfaction (Patient Global Impression of Change, PGIC) and other functional outcomes including disability (Oswestry Disability Index, ODI) and sleep. Key inclusion criteria include diagnosis of predominantly neuropathic pain of trunk and/or limbs for at least 6- months, and no back surgery within 6-months prior to screening.

Results

The study successfully met its primary endpoint (p<0.0001) based on a prespecified cohort of 20 subjects. A 6.1-point reduction (p<0.0001) in mean low back pain score at 3 months was reported with a 95% responder rate (≥50% improvement in pain relief). A 31-point improvement in disability (ODI) and high patient satisfaction ratings (85% reported much improved or very much improved, PGIC) were found. At the FAST-SCS activation visit, FAST responders achieved maximum paresthesia-free pain relief within a mean of 5.4-minutes.

Discussion

Preliminary results from this ongoing FAST prospective study suggests that profound, significant pain relief along with improvement in functional outcomes may be achieved in chronic pain patients with FAST therapy and additional SCS therapy options. With availability of multiple modalities in SCS systems, the capability for rapid onset of analgesia is particularly useful in evaluating what may be best suited for patients.

Conclusions

Significant pain relief and improvement in functional outcomes were reported in the FAST prospective study. These study results are consistent with published real-world experience that has assessed over 200 patients.⁵

References

1. Metzger CS, et al. A novel fast-acting sub-perception spinal cord stimulation therapy enables rapid onset of analgesia in patients with chronic pain. Expert Rev Med Devices 2021 Mar; 18(3): 299-306.

2. Ferro R, Pei Y, Jain R. Significant Pain Relief Using an SCS System Delivering Novel, Fast-Acting Sub-Perception Therapy [Abstract e-poster] Annual Meeting of the North American Neuromodulation Society, 2023.

3. Bayerl S, Paz Solis JF, Matis G, et al. Clinical Outcomes Using A New Fast Acting Sub Perception Therapy For Chronic Pain A Multicenter European Observational Real World Study [Abstract Poster 113]. Annual Meeting of the North American Neuromodulation Society, 2023.

4. Gilbert JE, Titus N, Zhang T, Esteller R, Grill WM. Surround Inhibition Mediates Pain Relief by Low Amplitude Spinal Cord Stimulation Modeling and Measurement. eNeuro 2022. Sep 22.ENEURO.0058-22.

5. Metzger C, Hammond MB, Ferro R, et al. Outcomes of a Large, Multicenter, Real-World Study using an SCS System Engaging Surround Inhibition [Abstract Poster 80]. Annual Meeting of the North American Neuromodulation Society, 2023.

Learning Objectives

1. To assess the FAST-SCS responder rate (defined as >50% pain relief when using FAST-SCS) among patients implanted with an SCS system

2. To assess the duration of onset of pain relief following FAST-SCS activation in FAST-SCS responders

3. To assess pain relief and functional outcomes in patients with an SCS system capable of FAST-SCS.