Welcome to the e-INS 2023 Interactive Program

Introduction

Unlike conventional spinal cord stimulation (SCS)—which employs single pulses delivered at a fixed rate to the dorsal spinal cord—burst SCS uses a fixed rate, five-pulse burst of stimuli as a treatment for chronic pain. The electrical charge per second (i.e., the battery depletion) is three times greater with burst SCS although burst SCS is generally programmed at lower amplitudes compared to conventional SCS.¹ Mechanistic explanations have suggested burst SCS differentially modulates the medial and lateral pain pathways versus conventional SCS.² Differences in neural activation resulting from either burst or conventional SCS may be quantified with the spinal evoked compound action potential (ECAP), an electrical measure of synchronous neural activation. Here, we use ECAPs acquired from both the ALS and dorsal columns in sheep to assess these differences and gain mechanistic insight into both types of SCS.

Materials / Methods

Seven sheep were each implanted with a dorsal stimulation lead at T9/T10, a dorsal ECAP sensing lead at T6/T7, and a lead also at T9/T10 but adjacent to the ALS (Fig. 1). Both burst and conventional SCS with swept stimulation amplitudes up to the visual motor threshold (vMT) were delivered to three different dorsal spinal locations,³ and ECAP thresholds (ECAPTs) were calculated for all combinations.⁴ Then, changes in ALS activation for both types of SCS was assessed using test stimulation delivered to the ALS.

Fig. 1

Results

The ALS ECAP recordings were separated into three different bins per stimulation location for both the burst and conventional dorsal SCS—sub-ECAPT, sub-ECAPT to vMT, and supra-vMT (Fig. 2). In all cases, no significant difference (p > 0.05) was noted between burst and conventional SCS for these three bins for all three stimulation sites. Further, both burst and conventional SCS potentiated ALS ECAPs in an equivalent manner as stimulation amplitudes were increased.

Fig. 2

Discussion

When dosed equivalently relative to the ECAPT—a measure that correlates with the perception threshold—burst SCS does not result in differentially unique changes in ALS activation versus conventional SCS; additionally, burst SCS below the ECAPT does not result in any discernable excitability changes in the neural pathways feeding pain relevant supraspinal sites.

Conclusions

Differences noted previously between burst and conventional SCS results (i.e., in terms of clinical benefit)⁵ may simply result from non-equivalent dosing between these stimulation modalities.

References

¹De Ridder D, Vanneste S, Plazier M, Van Der Loo E, Menovsky T. Burst spinal cord stimulation: Toward paresthesia-free pain suppression. Neurosurgery. 2010;66(5):986-990. doi:10.1227/01.NEU.0000368153.44883.B3

²De Ridder D, Vanneste S. Burst and Tonic Spinal Cord Stimulation: Different and Common Brain Mechanisms. Neuromodulation. 2016;19(1):47-59. doi:10.1111/ner.12368

³Al-Kaisy A, Baranidharan G, Palmisani S, et al. Comparison of Paresthesia Mapping to Anatomical Placement in Burst Spinal Cord Stimulation: Initial Trial Results of the Prospective, Multicenter, Randomized, Double-Blinded, Crossover, CRISP Study. Neuromodulation. 2020;23(5):613-619. doi:10.1111/ner.13104

⁴Pilitsis JG, Chakravarthy K V, Will AJ, et al. The Evoked Compound Action Potential as a Predictor for Perception in Chronic Pain Patients: Tools for Automatic Spinal Cord Stimulator Programming and Control. Front Neurosci. 2021;15:881. doi:10.3389/fnins.2021.673998

⁵Deer T, Slavin K V, Amirdelfan K, et al. Success Using Neuromodulation With BURST (SUNBURST) Study: Results From a Prospective, Randomized Controlled Trial Using a Novel Burst Waveform. Neuromodulation. 2018;21(1):56-66. doi:10.1111/ner.12698

Learning Objectives

1. Differences between burst and conventional SCS; burst SCS consists of a cluster of 5 - 1 ms wide pulses delivered at 40 Hz, while conventional stimulation is a single pulse (but may also be of the same pulsewidth and frequency). Previous mechanistic discussions have described a differentially unique effect of burst SCS on the lateral and medial pain pathway.

2. ECAPs may be used as a quantitative measure of neural activation, not just from the dorsal columns but from the anterolateral tracts as well.

3. When dosed equivalently using ECAPs, no differentially unique effect is noted with burst versus conventional SCS. Mechanistic differences noted previously between burst and conventional SCS may have resulted from non-equivalent dosing between the stimulation paradigms.

Introduction

Chronic pain patients may experience impairments in multiple health-related domains. The design and interpretation of clinical trials of chronic pain interventions, however, remains primarily focused on treatment effects on pain intensity. This study investigates a novel, multidimensional holistic treatment response to ECAP-controlled closed-loop spinal cord stimulation (CL-SCS) versus open-loop SCS (OL-SCS) as well as the degree of neural activation that produced that treatment response through 36-month follow-up.

Materials / Methods

The EVOKE multicentre, double-blind, parallel-arm RCT was designed to evaluate the safety and efficacy of ECAP-based therapy to treat chronic back and leg pain (NCT02924129).^1,2 Outcome data for pain intensity, physical function, health-related quality-of-life, sleep quality and emotional function were collected. Evaluation of holistic treatment response considered whether the baseline score was worse than normative values and whether minimal clinical important differences (MCIDs) were reached in each of the domains impaired at baseline.³ A cumulative responder score was calculated to reflect total MCIDs across all domains. Data analysis followed the intention-to-treat principle. Neural activation accuracy, defined as the deviation of the observed ECAP response from the prescribed ECAP was measured.

Results

Patients were randomised to CL-SCS (n=67) or OL-SCS (n=67). A greater proportion of patients with CL-SCS (44.8% vs 28.4%) were holistic responders at 36-month follow-up. The cumulative responder score was significantly greater for CL-SCS patients at 3-months (11.4 vs 8.7, MD=2.6, 95% CI=0.3-5.0, p=0.028), and resulted in more than 3 additional MCIDs at 12- (11.1 vs 7.7, MD=3.4, 95% CI=1.0-5.7, p=0.005), 24- (10.2 vs 6.8, MD=3.4, 95% CI=1.3-5.5, p=0.002) and 36-month follow-up (10.5 vs 7.2, MD=3.3, 95% CI=1.1-5.5, p=0.003). Neural activation was 3 times more accurate in CL-SCS (p<0.001 at all timepoints).

Discussion

Responders in multiple domains were observed as early as 3-months following SCS implantation and sustained through 36-months. This was particularly evident in the CL-SCS group which showed no degradation in responder rates across multiple domains. The superior patient-reported outcomes observed with CL-SCS show that ECAP-controlled therapy was delivered with greater accuracy and that this can provide a greater breadth and depth of improvements in multiple domains. This is unique in the current SCS literature.

Conclusions

The results of this study suggest that CL-SCS can result in true relief of the complex, multifactorial personal experience that patients describe as chronic pain. Additionally, with consistent neural activation at the prescribed level, CL-SCS provided superior and durable outcomes in all domains and at all timepoints when compared to OL-SCS.

References

1. Mekhail N, et al. Long-term safety and efficacy of closed-loop spinal cord stimulation to treat chronic back and leg pain (Evoke): a double-blind, randomised, controlled trial. Lancet Neurol 2020; 19: 123-134.

2. Mekhail N, et al. Durability of Clinical and Quality-of-Life Outcomes of Closed-Loop Spinal Cord Stimulation for Chronic Back and Leg Pain: A Secondary Analysis of the Evoke Randomized Clinical Trial. JAMA Neurol 2022; 79: 251-260.

3. Levy RM, et al. Holistic Treatment Response: An International Expert Panel Definition and Criteria for a New Paradigm in the Assessment of Clinical Outcomes of Spinal Cord Stimulation. Neuromodulation 2023; Online ahead of print.

Learning Objectives

1. Evaluation of a holistic treatment response is paramount in chronic pain populations given that impairment can be present in several domains other than just pain intensity.

2. ECAP-controlled closed-loop SCS can provide a holistic response, characterised by improvement of at least one MCID in all measured health-related domains impaired at baseline.

3. ECAP-guided programming delivered for open-loop SCS and closed-loop SCS appear to provide clinical benefit.

Introduction

Evoked compound action potential (ECAP)-controlled closed-loop spinal cord stimulation (SCS) provides superior pain relief compared to traditional ‘open-loop’ SCS due to its ability to maintain consistent and accurate activation of the spinal cord [1],[2]. Results from controlled studies are sometimes hard to repeat in the real-world. Here, interim real-world results of the multi-center data collection study are presented from 13 centers across Europe.

Materials / Methods

This multi-center data collection (Clinical Trials registry ID: NCT05272137) was designed to collect patient reported outcomes for pain relief, Verbal Numerical Rating Scale (VNRS) and satisfaction (five options, ranging from “Very Satisfied” to “Very Unsatisfied”). Additionally, electrophysiological data (ECAPs) and device data (stimulation parameters, patient usage) were collected during standard-of-care visits for patients treated with ECAP-controlled closed-loop SCS system (Evoke® SmartSCS^TM, Saluda Medical, Australia) in a real-world setting under normal clinical use in Europe.

Interim results from this study are presented below. Patients presenting with CRPS Type 1 and 2, PSPS type 2 and polyneuropathy, post amputation stump pain and peripheral plexopathy were enrolled. Post-market visit requirements followed standard of care; if a follow-up visit was not performed, or patient outcomes were not taken due to time limitations, it was not regarded as a protocol deviation.

Results

A total of 153 patients underwent permanent implantation of the ECAP-controlled closed-loop system. Mean (±SEM) baseline (n=153) VNRS scores were 8.12±0.10. At 3-months (n=103) average VNRS scores decreased to 2.43±0.22, at 6-months (n=83) to 2.51±0.26, at 12-months (n=74) to 2.50±0.26 and at 24-months to 2.46±0.40 (n=24; Fig.1A).

At 12-months there were 80% responders (≥50% pain relief), and 43% high-responders (≥80% pain relief; Fig.1B).

At 12-months, 92% of the patients reported being very satisfied or satisfied with their therapy (Fig.1C; n=68 of 74 patients). Patients used closed-loop SCS at 12-months (n=48) above perception threshold (Neural Activation Level; Mode ECAP: 9.8µV) identified in-clinic (Fig.1D).

Discussion

Results strongly suggest that ECAP-controlled closed-loop SCS can lead to a high degree of pain relief and patient satisfaction 12-months post-implantation in a real-world setting. The final results will be presented at the eINS conference.

Conclusions

Preliminary real-world results are comparable to results from the controlled AVALON multi-center-study [3] and the controlled EVOKE RCT [1] in pain relief outcomes.

References

[1] N. Mekhail et al., “Long-term safety and efficacy of closed-loop spinal cord stimulation to treat chronic back and leg pain (Evoke): a double-blind, randomised, controlled trial,” Lancet Neurol., p. S1474442219304144, Dec. 2019, doi: 10.1016/S1474-4422(19)30414-4.

[2] N. Mekhail et al., “Durability of Clinical and Quality-of-Life Outcomes of Closed-Loop Spinal Cord Stimulation for Chronic Back and Leg Pain: A Secondary Analysis of the Evoke Randomized Clinical Trial,” JAMA Neurol., vol. 79, no. 3, pp. 251–260, Jan. 2022, doi: 10.1001/jamaneurol.2021.4998.

[3] M. Russo et al., “Sustained Long-Term Outcomes With Closed-Loop Spinal Cord Stimulation: 12-Month Results of the Prospective, Multicenter, Open-Label Avalon Study,” Neurosurgery, Feb. 2020, doi: 10.1093/neuros/nyaa003.

[4] C. Brooker et al., “ECAP‐Controlled Closed‐Loop Spinal Cord Stimulation Efficacy and Opioid Reduction Over 24‐Months: Final Results of the Prospective, Multicenter, Open‐Label Avalon Study,” Pain Pract., 2021.

Learning Objectives

1. To learn that ECAPs are used to adjust stimulation levels in real-time to maintain consistent activation of the spinal cord.

2. To provide that ECAP-controlled closed-loop SCS in the real-world can lead to a high degree of pain relief and patient satisfaction 12-months post-implantation.

3. To provide evidence that real-world results are comparable to results from the AVALON multi-center-study and the EVOKE RCT in pain relief outcomes.

Introduction

Raynaud's phenomenon (RP) is an episodic vasospasm of the peripheral arteries that causes cyanosis, erythema, pain, paraesthesia’s, and sometimes ulceration of the fingers and/or toes¹. There are few reports, mostly case series, on the benefits of spinal cord stimulation (SCS) for the treatment of RP^2–19. However, there is a lack of objective evidence on SCS induced modulation of the sympathetic system (e.g., vasodilation) in this condition.

We hypothesize that evoked compound action potential-(ECAP)-controlled closed-loop-SCS may relieve pain and reduce the severity and frequency of Raynaud's attacks. Furthermore, we hypothesize that the retrograde effects of ECAP-controlled closed-loop-SCS may improve peripheral blood flow. Here, objective results on the effects on peripheral circulation and subjective changes in the frequency and severity of Raynaud's attacks will be presented. Full cohort data will be introduced at eINS.

Materials / Methods

This is a prospective, single-centre pilot study to evaluate the efficacy of ECAP-controlled closed-loop-SCS (Evoke® SmartSCS^TM, Saluda Medical, Australia) in the treatment of RP. Patient outcomes such as Raynaud severity/condition score, Cochin-Hand-Function-Scale, SHAQ-RP-VAS, EQ-5D-5L, PGIC, stimulation parameters, objective peripheral blood flow assessments and neurophysiological measurements were collected at baseline, trial end, 1-month, 3-months, and 6-months.

Results

The mean age ±standard deviation (±SD) patients was 45.5±15.5 years (n=10), and 80% were female.

Fig.1A shows an occluded distal digital artery due to RP, whereas Fig.1B shows the same section after 3-months of SCS, revealing blood flow restoration at the level of the Distal interphalangeal joint.

Pathological arterial occlusions decreased by 49% (n=8; Fig.1C) at 6-months after implantation.

Recording and measurement of patients' ECAPs in the clinic are presented in Fig.1D. The Voltage (µV) increased with increasing current.

The mean baseline (±SEM; n=9) Raynaud's condition score was 6.6±0.7 and decreased to 2.6±0.7 6-months after implantation (n=8; Fig.2A). Patients experienced a clinically meaningful change in symptom severity as informed by the Raynaud's condition score (-1.4)²⁰.

The mean baseline (±SEM; n=9) Cochin-Hand-Function-Scale score was 31.6±8.2 and decreased to 17.4±7.7 6-months after implantation (n=8; Fig.2B).

Discussion

This study demonstrates for the first time that RP-related pathological arterial occlusions and Raynaud symptoms can be treated with a novel ECAP-controlled closed-loop-SCS system.

Conclusions

In conclusion, ECAP-controlled closed-loop-SCS alleviates RP symptoms and improves peripheral blood flow. Longer-term follow up and larger controlled studies are needed to confirm these preliminary pilot study results.

References

1. Herrick, A.L. (2012). The pathogenesis, diagnosis and treatment of Raynaud phenomenon. Nat. Rev. Rheumatol. 8, 469–479. https://doi.org/10.1038/nrrheum.2012.96.

2. Barba, A., Escribano, J., and García-Alfageme, A. (1992). The treatment of vasospastic disease by chronic spinal cord stimulation. A case report. Angiologia 44, 136–138.

3. Benyamin, R., Kramer, J., and Vallejo, R. (2007). A Case of Spinal Cord Stimulation in Raynaud’s Phenomenon: Can Subthreshold Sensory Stimulation Have an Effect? Pain Physician, 6.

4. Chapman, K.B., Kloosterman, J., Schor, J.A., Girardi, G.E., van Helmond, N., and Yousef, T.A. (2021). Objective improvements in peripheral arterial disease from dorsal root ganglion stimulation: a case series. Ann. Vasc. Surg. 74, 519-e7.

5. Devulder, J., De Colvenaer, L., Rolly, G., Caemaert, J., Calliauw, L., and Martens, F. (1990). Spinal cord stimulation in chronic pain therapy. Clin. J. Pain 6, 51–56.

6. ERTILAV, E., and AYDIN, O.N. (2020). Spinal cord stimulator for the treatment of ischemic pain-Burger’s Disease and Raynaud’s disease: A report of 2 cases and literature.

7. Francaviglia, N., Silvestro, C., Maiello, M., Bragazzi, R., and Bernucci, C. (1994). Spinal cord stimulation for the treatment of progressive systemic sclerosis and Raynaud’s syndrome. Br. J. Neurosurg. 8, 567–571.

8. Giglio, M., Preziosa, A., Rekatsina, M., Viswanath, O., Urits, I., Varrassi, G., Paladini, A., and Puntillo, F. (2021). Successful spinal cord stimulation for necrotizing Raynaud’s phenomenon in COVID-19 affected patient: the nightmare comes back. Cureus 13.

9. Issa, M.A. (2012). Cervical Spinal Cord Stimulation with 5-ColumnPaddle Lead In Raynaud’s Disease. Pain Physician 4;15, 303–309. 10.36076/ppj.2012/15/303.

10. Ito, H., Tanei, T., Sugawara, K., Sando, Y., and Hori, N. (2022). Spinal cord stimulation for the treatment of pain and toe ulceration associated with systemic sclerosis: a case report. FUKUSHIMA J. Med. Sci. 68, 37–41. 10.5387/fms.2021-33.

11. Münster, T., Tiebel, N., Seyer, H., and Maihöfner, C. (2012). Modulation of Somatosensory Profiles by Spinal Cord Stimulation in Primary Raynaud′s Syndrome: SCS Influences QST in Primary Raynaud′s Syndrome. Pain Pract. 12, 469–475. 10.1111/j.1533-2500.2012.00531.x.

12. Neuhauser, B., Perkmann, R., Klinger, P.J., Giacomuzzi, S., Kofler, A., and Fraedrich, G. (2001). Clinical and Objective Data of Spinal Cord Stimulation for the Treatment of Severe Raynaud’s Phenomenon. EJVES Extra 1, 3–4. 10.1053/ejvx.2000.0002.

13. Niclauss, L., Roumy, A., and Gersbach, P. (2013). Spinal Cord Stimulation in Thromboangiitis Obliterans and Secondary Raynaud’s-Syndrome. EJVES Extra 26, e9–e11. 10.1016/j.ejvsextra.2013.03.007.

14. Provenzano, D.A., Nicholson, L., Jarzabek, G., Lutton, E., Catalane, D.B., and Mackin, E. (2011). Spinal Cord Stimulation Utilization to Treat the Microcirculatory Vascular Insufficiency and Ulcers Associated with Scleroderma: A Case Report and Review of the Literature. Pain Med. 12, 1331–1335. 10.1111/j.1526-4637.2011.01214.x.

15. Robaina, F.J., Dominguez, M., Díaz, M., Rodriguez, J.L., and de Vera, J.A. (1989). Spinal cord stimulation for relief of chronic pain in vasospastic disorders of the upper limbs. Neurosurgery 24, 63–67.

16. Sciacca, V., Petrakis, I., and Borzomati, V. (1998). Spinal cord stimulation in vibration white finger. VASA Z. Gefasskrankheiten 27, 247–249.

17. Sibell, D.M., and Stacey, B.R. (2005). Successful Use of Spinal Cord Stimulation in the Treatment of Severe Raynaud’s Disease of the Hands. CASE Rep. 102, 5.

18. Ting, J.C., Fukshansky, M., and Burton, A.W. (2007). Treatment of Refractory Ischemic Pain from Chemotherapy-Induced Raynaud?s Syndrome With Spinal Cord Stimulation. Pain Pract. 7, 143–146. 10.1111/j.1533-2500.2007.00122.x.

19. Wolter, T., and Kieselbach, K. (2011). Spinal Cord Stimulation for Raynaud’s Syndrome: Long-Term Alleviation of Bilateral Pain With a Single Cervical Lead: SPINAL CORD STIMULATION FOR RAYNAUD’S SYNDROME. Neuromodulation Technol. Neural Interface 14, 229–234. 10.1111/j.1525-1403.2011.00332.x.

20. Khanna, P.P., Maranian, P., Gregory, J., and Khanna, D. (2010). The minimally important difference and patient acceptable symptom state for the Raynaud’s condition score in patients with Raynaud’s phenomenon in a large randomised controlled clinical trial. Ann. Rheum. Dis. 69, 588–591. 10.1136/ard.2009.107706.

Learning Objectives

1. To learn that pathological arterial occlusions in patients with Raynaud’s Phenomenon can be treated with ECAP-controlled closed-loop-SCS.

2. To show that Raynaud symptoms can be treated with ECAP-controlled closed-loop-SCS.

3. To provide that overall assessment of an SCS therapy for chronic neuropathic pain in Raynaud’s Phenomenon requires the implementation of objective and multiple patient-related outcomes measures.

Introduction

Differential Target Multiplexed spinal cord stimulation is an advanced SCS therapy inspired by preclinical research demonstrating that multiplexed signals can differentially modulate neurons and glial cells.¹ Differential Target Multiplexed SCS has shown superior back pain relief to traditional SCS.² Derivatives of the Differential Target Multiplexed waveform are being investigated to understand opportunities for therapy personalization. Energy-conserving approaches altering amplitude, frequency, and pulse width, have the potential to impact patient experience with rechargeable and non-rechargeable devices.

Materials / Methods

This prospective, multi-center, open-label, post-market study evaluated the efficacy and energy use of reduced-energy derivative of Differential Target Mutliplexed SCS, also known as DTM™ SCS (Medtronic, Minneapolis, MN, USA). . Patients who were candidates for SCS with an overall Visual Analog Score (VAS) of ≥6 with moderate to severe chronic, intractable back and leg pain were eligible.Eligible subjects underwent an SCS trial programmed with a reduced energy Differential Target Multiplexed SCS derivative, and if successful, subjects continued in the study. Evaluation visits occurred at 1-, 3-, 6-, and 12-months post-activation.

Results

57 subjects enrolled at 12 US sites from November 2020 through June 2021. Subjects had an average age of 63.2 years and 57.9% were female. The main etiologies included post-laminectomy pain/PSPS-T2 (61.4%), radicular pain syndrome (29.8%), and degenerative disc disease (8.8%). Average time since onset of chronic, intractable pain was 13.4 years. Forty-nine subjects started an SCS trial, 43 completed an SCS trial end visit, 35 subjects were implanted with a rechargeable neurostimulator, and 27 completed the 12-Month visit. Implanted subjects reported pain relief, therapy satisfaction and improved quality of life through 12-months. The primary objective analysis demonstrated a mean reduction (standard deviation) of 3.9cm (2.5) in overall pain, as measured by VAS, from baseline at the 3-month follow-up. Changes in overall pain were clinically sustained at 3- , 6-, and 12-months with 50.4%, 52.4%, 56.1% improvement, respectively. At 12-months, 76% of subjects improved to a less disabled ODI category compared to baseline and 89% of subjects reported therapy satisfaction. Outcomes including changes in pain intensity, quality of life, activity and safety data will be presented through 12-month follow-up.

Discussion

The use of a Differential Target Multiplexed SCS derivative in this study resulted in clinically meaningful pain relief as well as improved function and a high degree of therapy satisfaction.

Conclusions

This study suggests that a Differential Target Multiplexed SCS derivative therapy with a reduced-energy profile could impact patient experience with rechargeable devices and may benefit those patients best suited for recharge-free devices.

References

1. Vallejo R, Kelley CA, Gupta A, et al. Modulation of neuroglial interactions using differential target multiplexed spinal cord stimulation in an animal model of neuropathic pain. Molecular Pain 2020; 16:1744806920918057; doi:10.1177/1744806920918057.

2. Fishman M, Cordner H, Justiz R, et al. 12-Month Results from Multicenter, Open-Label, Randomized Controlled Clinical Trial Comparing Differential Target Multiplexed Spinal Cord Stimulation and Traditional Spinal Cord Stimulation in Subjects with Chronic Intractable Back Pain and Leg Pain. Pain Pract. 2021; 00: 1– 12. doi: 10.1111/papr.13066. Epub ahead of print.

Learning Objectives

1. Energy-conserving approaches altering amplitude, frequency, and pulse width, have the potential to impact patient experience with rechargeable and non-rechargeable devices.

2. This prospective, multi-center, open-label, post-market study evaluated the efficacy and energy use of reduced-energy Differential Target Multiplexed derivative.

3. The use of a Differential Target Multiplexed SCS derivative in this study resulted in clinically meaningful pain relief as well as improved function and a high degree of therapy satisfaction.

Introduction

Few treatment options exist for chronic back pain patients who have failed conventional medical management (CMM) and who have not had and are not candidates for spine surgery, a condition we refer to as non-surgical refractory back pain (NSRBP). Access to spinal cord stimulation (SCS) is inconsistent for NSRBP due to limited clinical evidence.¹ Twenty-four-month (24M) outcomes are reported from a RCT that compared 10kHz-SCS to CMM in the treatment of NSRBP.

Materials / Methods

Patients were enrolled if ineligible for surgery based on surgical consultation, had moderate to severe refractory back pain, and no previous spine surgery.² Patients were randomized 1:1 to 10kHz-SCS plus CMM or CMM alone. The 10kHz-SCS arm were implanted following successful trial (≥50% pain relief). Either group could crossover over at 6 months. Patients who consented to a study extension were followed to 24M. Outcomes included VAS, Oswestry Disability Index (ODI), quality-of-life (EQ-5D-5L), 3-item Pain Sleep Questionnaire (PSQ-3), opioid use, patient’s global impression of change (PGIC), and safety.

Results

There were 159 patients randomized either to CMM or 10kHz-SCS group with similar baseline characteristics, at 15 sites, with 91% reporting degenerative disc disease and/or spondylosis, an average of 8 years since diagnosis, and extensive previous CMM.³ Primary and secondary endpoints at 3 and 6 months showed 10kHz-SCS to be superior to CMM (p<0.001) in terms of pain relief, disability, quality-of-life, and opioid reduction.³ At 6 months no patients in the 10kHz-SCS arm chose to crossover, while 74.7% (56/75) in the CMM arm crossed over, resulting in 125 total permanent implanted (PI) patients. Figure 1 shows the improvements in outcomes in the PI group compared to the CMM control and published MCIDs.

At 24M, percent of responders (≥50% pain relief) was 82% (Figure 2a), and 90% of patients met at least one of: pain responder, ODI 10pt improvement, 50% sleep improvement, and “Better” or “A Great Deal Better” on PGIC (Figure 2b). Forty-five of the PI group reported opioid use, and 62% of those decreased or stopped during the study. Device explants due to patient dissatisfaction with SCS therapy was low (2.4%) over 24M.

Discussion

The quality-of-life improvement through 24M supports the recently published evaluation of cost-effectiveness at 2.1 years post-implant.⁴

Conclusions

The clinical effects seen with 10kHz-SCS, including pain relief, decreased disability, reduced opioid use, and improved sleep and quality-of-life were profoundly greater than CMM alone and were durable through 24M in these NSRBP patients.

References

1. Gore M, Sadosky A, Stacey BR, Tai KS, Leslie D. The burden of chronic low back pain: clinical comorbidities, treatment patterns, and health care costs in usual care settings. Spine (Phila Pa 1976). 2012;37:E668-677.

2. Eckermann JM, Pilitsis JG, Vannaboutathong C, Wagner BJ, Province-Azalde R, Bendel MA. Systematic Literature Review of Spinal Cord Stimulation in Patients With Chronic Back Pain Without Prior Spine Surgery. Neuromodulation. Aug 18 2021.

3. Patel N, Calodney A, Kapural L, Province-Azalde R, Lad SP, Pilitsis J, Wu C, Cherry T, Subbaroyan J, Gliner B, Caraway D. High-Frequency Spinal Cord Stimulation at 10 kHz for the Treatment of Nonsurgical Refractory Back Pain: Design of a Pragmatic, Multicenter, Randomized Controlled Trial. Pain Practice: the official journal of World Institute of Pain 2021;21(2):171-183.

4. Kapural L, Jameson J, Johnson C, et al. 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. Feb 11 2022:1-12. doi:10.3171/2021.12.SPINE211301.

5. Patel NP, Wu C, Lad SP, et al. Cost-effectiveness of 10-kHz spinal cord stimulation therapy compared with conventional medical management over the first 12 months of therapy for patients with nonsurgical back pain: randomized controlled trial. J Neurosurg Spine. Oct 21 2022:1-9. doi:10.3171/2022.9.SPINE22416

Learning Objectives

1) Understand the definition of nonsurgical refractory back pain as chronic back pain patients who have failed conventional medical management (CMM) and who have not had and are not candidates for spine surgery.

2) The primary results of this study showed 10kHz SCS superior to conventional medical management (p<0.001) in terms of pain relief, disability, quality-of-life, and opioid reduction at 3 and 6 months.

3) The clinical effects seen with 10 kHz SCS, including pain relief, decreased disability, reduced opioid use, and improved sleep and quality of life were profoundly greater than CMM alone and were durable through 24 months in this analysis of all implanted patients from the NSRBP RCT. The durability in the EQ-5D-5L index through 24 months supports the assumptions leading to the evaluation of cost-effectiveness at 2.1 years post-implant.