Tonic Spinal Cord Stimulation Research Articles

ID: 212641 Salvage Therapy With Bilateral T12 and S1 DRG Stimulation for Post-Laminectomy Syndrome: A Case Report

Neuromodulation with tonic spinal cord stimulation (t-SCS) is well evidenced to manage chronic pain syndromes. However, for patients with post-laminectomy syndrome refractory to t-SCS, salvage therapies such as alternative waveforms of SCS (burst, high frequency, or multiple waveform) or dorsal root ganglion (DRG) stimulation have been studied. DRG stimulation is an emerging option for salvage therapy and was shown to be non-inferior and superior to t-SCS in treating lower extremity neuropathic pain for CRPS in the ACCURATE study. DRG stimulation’s use as salvage therapy for post-laminectomy syndrome is poorly reported. In this case, we present the treatment approach with DRG stimulation as salvage treatment for post-laminectomy syndrome refractory to t-SCS.

The Effectiveness of Various Types of Electrical Stimulation of the Spinal Cord for Chronic Pain in Patients with Postherpetic Neuralgia: A Literature Review.

Postherpetic neuralgia (PHN) is a severe condition that remains a challenge to treat. Spinal cord stimulation (SCS) is used in cases of insufficient efficacy of conservative treatment. However, in contrast to many other neuropathic pain syndromes, there is a huge problem in reaching long-term stable pain relief in patients with PHN using conventional tonic SCS. The objective of this article was to present a review of the current management strategies of PHN, their efficacy, and safety. We searched for articles containing the keywords "spinal cord stimulation AND postherpetic neuralgia," "high-frequency stimulation AND postherpetic neuralgia," "burst stimulation AND postherpetic neuralgia" and "dorsal root ganglion stimulation AND postherpetic neuralgia" in Pubmed, Web of Science, and Scopus databases. The search was limited to human studies published in the English language. There were no publication period limitations. Bibliographies and references of selected publications on neurostimulation for PHN were further manually screened. The full text of each article was studied once the abstract was analyzed by the searching reviewer and found appropriate. The initial search yielded 115 articles. Initial screening based on abstract and title allowed us to exclude 29 articles (letters, editorials, and conference abstracts). The full-text analysis allowed us to exclude another 74 articles (fundamental research articles, research utilizing animal subjects, and systemic and nonsystemic reviews) and results of PHN treatment presented with other conditions, leaving 12 articles for the final bibliography. 12 articles reporting on the treatment of 134 patients with PHN were analyzed, with a disproportionally large amount of traditional SCS treatment than that to alternative SCS: DRGS (13 patients), burst SCS (1 patient), and high-frequency SCS (2 patients). Long-term pain relief was achieved in 91 patients (67.9%). The mean VAS score improvement was 61.4% with a mean follow-up time of 12.85 months. Although the number of patients in alternative SCS studies was very limited, almost all of them showed good responses to therapy with more than 50% VAS improvement and reduction of analgesic dosage. The article contains a review analysis of 12 articles concerning the current methods of treatment for postherpetic neuralgia including conservative treatment, spinal cord stimulation, and novel neuromodulation strategies. Available information on the pathophysiology of PHN and the effect or stimulation on its course, together with a number of technical nuances concerning various types of neurostimulation are also elucidated in this article. A number of alternative invasive treatments of PHN are also discussed. Spinal cord stimulation is an established treatment option for patients with pharmacologically resistant PHN. High-frequency stimulation, burst stimulation, and dorsal root ganglion stimulation are promising options in the management of PHN due to the absence of paresthesias which can be painful for patients with PHN. But more research is still required to recommend the widespread use of these new methods.

Heterogeneous Cortical Effects of Spinal Cord Stimulation

ObjectivesThe understanding of the cortical effects of spinal cord stimulation (SCS) remains limited. Multiple studies have investigated the effects of SCS in resting-state electroencephalography. However, owing to the large variation in reported outcomes, we aimed to describe the differential cortical responses between two types of SCS and between responders and nonresponders using magnetoencephalography (MEG). Materials and MethodsWe conducted 5-minute resting-state MEG recordings in 25 patients with chronic pain with active SCS in three sessions, each after a one-week exposure to tonic, burst, or sham SCS. We extracted six spectral features from the measured neurophysiological signals: the alpha peak frequency; alpha power ratio (power 7–9 Hz/power 9–11 Hz); and average power in the theta (4–7.5 Hz), alpha (8–12.5 Hz), beta (13–30 Hz), and low-gamma (30.5–60 Hz) frequency bands. We compared these features (using nonparametric permutation t-tests) for MEG sensor and cortical map effects across stimulation paradigms, between participants who reported low (< 5, responders) vs high (≥ 5, nonresponders) pain scores, and in three representative participants. ResultsWe found statistically significant (p < 0.05, false discovery rate corrected) increased MEG sensor signal power below 3 Hz in response to burst SCS compared with tonic and sham SCS. We did not find statistically significant differences (all p > 0.05) between the power spectra of responders and nonresponders. Our data did not show statistically significant differences in the spectral features of interest among the three stimulation paradigms or between responders and nonresponders. These results were confirmed by the MEG cortical maps. However, we did identify certain trends in the MEG source maps for all comparisons and several features, with substantial variation across participants. ConclusionsThe considerable variation in cortical responses to the various SCS treatment options necessitates studies with sample sizes larger than commonly reported in the field and more personalized treatment plans. Studies with a finer stratification between responders and nonresponders are required to advance the knowledge on SCS treatment effects.

Spinal Cord High-Frequency Stimulation. The Current Experience and Future Directions.

Spinal cord stimulation (SCS) is a neuromodulation technology that has emerged as a valid treatment for chronic intractable neuropathic pain. After conventional tonic SCS, new waveforms of stimulation, like high frequency (HF), have proved that they can provide safe and effective pain relief. In addition, SCS is now being utilized more broadly as a potential treatment for a range of indications, including motor disorders and spasticity. Our study presents a retrospective analysis of 20 patients with heterogenous aetiologies of neuropathic pain treated with HF stimulation, after a standardized protocol in a temporary trial. We observed a significant improvement in pain relief according to comparisons of numerical rating scale (NRS) scores before the procedure, after the clinical trial and at latest follow-up. Two unusual clinical cases were also reported, and the pertinent literature was discussed.

Pulse Intensity Effects of Burst and Tonic Spinal Cord Stimulation on Neural Responses to Brushing in Patients With Neuropathic Pain

ObjectivesTonic spinal cord stimulation (SCS) is accompanied by paresthesia in affected body regions. Comparatively, the absence of paresthesia with burst SCS suggests different involvement of the dorsal column system conveying afferent impulses from low-threshold mechanoreceptors. This study evaluated cortical activation changes during gentle brushing of a pain-free leg during four SCS pulse intensities to assess the effect of intensity on recruitment of dorsal column system fibers during burst and tonic SCS. Materials and MethodsTwenty patients using SCS (11 burst, nine tonic) for neuropathic leg pain participated. Brushing was administered to a pain-free area of the leg during four SCS intensities: therapeutic (100%), medium (66%), low (33%), and no stimulation. Whole-brain electroencephalography was continuously recorded. Changes in spectral power during brushing were evaluated using the event-related desynchronization (ERD) method in theta (4–7 Hz), alpha (8–13 Hz), and beta (16–24 Hz) frequency bands. ResultsBrushing was accompanied by a suppression of cortical oscillations in the range 4–24 Hz. Stronger intensities of burst and tonic SCS led to less suppression of 4–7 Hz and 8–13 Hz bands in parietal electrodes, and in central electrodes in the 16–24 Hz band, with the strongest, statistically significant suppression at medium intensity. Tonic SCS showed a stronger reduction in 4–7 Hz oscillations over right sensorimotor electrodes, and over right frontal and left sensorimotor electrodes in the 8–13 Hz band, compared to burst SCS. ConclusionsResults suggest that burst and tonic SCS are mediated by both different and shared mechanisms. Attenuated brushing-related ERD with tonic SCS suggests a gating of cortical activation by afferent impulses in the dorsal column, whereas burst may engage different pathways. Diminished brushing-related ERD at medium and therapeutic intensities of burst and tonic SCS points towards a nonlinear effect of SCS on somatosensory processing.

O095 / #831 SPINAL CORD STIMULATION USING TIME-DYNAMIC PULSES ACHIEVES FASTER AND LONGER REVERSAL OF ALLODYNIA IN A RAT MODEL OF NEUROPATHIC PAIN: TRACK 1: NEUROMODULATION FOR PAINFUL NEUROPATHIES / PERIPHERAL NERVE STIMULATION

Spinal cord stimulation (SCS) using time-dynamic pulses (TDPs) is an emerging field of neuromodulation and a promising advancement in SCS that, unlike conventional tonic SCS, modulates stimulation pulse parameters with signals that change continuously and automatically. Previously [1], we demonstrated the analgesic efficacy of TDPs delivered at sub-paresthesia amplitudes in a rat model of neuropathic pain (n=8 rats), and reported that TDPs with rate or amplitude modulation significantly reversed allodynia.

Allodynia, Hyperalgesia, (Quantitative) Sensory Testing and Conditioned Pain Modulation in Patients With Complex Regional Pain Syndrome Before and After Spinal Cord Stimulation Therapy

ObjectivesComplex regional pain syndrome (CRPS) is a chronic debilitating disease characterized by sensory abnormalities. Spinal cord stimulation (SCS) is an effective therapy for CRPS, but few studies have investigated the effects of SCS therapy on sensory characteristics. Therefore, this study investigated the effect of SCS on allodynia, hyperalgesia, electrical quantitative sensory testing (QST) parameters, and conditioned pain modulation (CPM) effect. Materials and MethodsThis study is part of a multicenter randomized controlled trial (ISRCTN 36655259). Patients with CRPS in one extremity and eligible for SCS were included. The outcome parameters allodynia (symptom and sign), hyperalgesia (symptom), sensory thresholds with QST, CPM effect, and pain scores were tested before and after three months of SCS (40-Hz tonic SCS). Both the CRPS-affected extremity and the contralateral, clinically unaffected extremity were used to test three sensory thresholds with electrical QST: current perception threshold (CPT), pain perception threshold (PPT), and pain tolerance threshold (PTT). The PTT also was used as a test stimulus for the CPM paradigm both before and after the conditioning ice-water test. Nonparametric testing was used for all statistical analyses. ResultsIn total, 31 patients were included for analysis. Pain, allodynia (sign and symptom), and hyperalgesia (symptom) were all significantly reduced after SCS therapy. On the unaffected side, none of the QST thresholds (CPT, PPT, and PTT) was significantly altered after SCS therapy. However, the CPT on the CRPS-affected side was significantly increased after SCS therapy. A CPM effect was present both before and after SCS. ConclusionsStandard 40-Hz tonic SCS significantly reduces pain, hyperalgesia, and allodynia in patients with CRPS. These findings suggest that SCS therapy should not be withheld from patients who suffer from allodynia and hyperalgesia, which contradicts previous findings derived from retrospective analysis and animal research.ISRCTN Registry: The ISRCTN registration number for the study is ISRCTN 36655259.

ID:16361 Burst Stimulation Therapy Improves Pain Relief and Emotional Well-Being in Patients With Waning SCS Therapy

Spinal cord stimulation (SCS) is a safe and effective treatment option for patients with chronic intractable pain. However, a portion of patients with SCS eventually develop loss of efficacy for several reasons including habituation, lead migration, and new pain emergence. Burst stimulation offers a unique mechanism of action that can potentially restore effectiveness where other stimulation therapies have failed. While tonic SCS modulates the lateral pain pathway, only passive recharge burst1 has been shown to influence both the lateral and medial pain pathway responsible for affective components of pain, such as catastrophizing and depression in addition to sensory pain.

Comparison of the Interference Effects on Somatosensory Evoked Potential from Tonic, Burst, and High-dose Spinal Cord Stimulations.

Spinal cord stimulations have been used widely to treat intractable neuropathic pain. The conventional spinal cord stimulation paradigm, the “tonic” type, suppresses excessive activation of wide dynamic range neurons in the dorsal horn via the collateral branch from the dorsal column. Therefore, preserved dorsal column function is an important prerequisite for tonic spinal cord stimulations. A tonic spinal cord stimulation requires eliciting paresthesia in the painful area due to stimulation of the dorsal column and dorsal root. Recent spinal cord stimulation paradigms, including burst and high-dose, are set below the paresthesia threshold and are proposed to have different pain reduction mechanisms. We conducted an interference study of these different stimulation paradigms on the somatosensory evoked potential (SEP) to investigate differences in the sites of action between tonic and new spinal cord stimulations. We recorded posterior tibial nerve-stimulated SEP in seven patients with neuropathic pain during tonic, burst, and high-dose stimulations. The total electrical energy delivered was calculated during SEP-spinal cord stimulation interference studies. High-dose stimulations could not reduce the SEP amplitude despite higher energy delivery than tonic stimulation. Burst stimulation with an energy similar to the tonic stimulation could not reduce SEP amplitude as tonic stimulation. The study results suggested different sites of action and effects on the spinal cord between the conventional tonic and burst or high-dose spinal cord stimulations.

Neuromodulation Interventions for the Treatment of Painful Diabetic Neuropathy: a Systematic Review.

Painful diabetic neuropathy (PDN) is a prevalent and debilitating condition, characterized by severe burning, tingling, and lancinating pain usually located in the distal lower extremities. In addition to manifesting with severe pain, PDN may also be associated with poor quality of life and sleep, mood disorders, burns, falls, and social withdrawal. The authors appraised the current body of literature for evidence on neuromodulation interventions for PDN. In patients with refractory PDN unresponsive to conventional medical management (glucose optimization and oral analgesic medications), there is level I evidence supporting the use of 10-kHz and tonic dorsal column spinal cord stimulation (SCS). Included studies reported significant associations between 10-kHz and tonic dorsal column SCS and superior analgesic outcomes, physical functioning, and patient satisfaction. Current level of evidence remains limited for other modalities of neuromodulation for PDN including burst SCS (level II-3), dorsal root ganglion SCS (level III), and peripheral nerve stimulation (level II-3). Some studies reported improvements in neurological physical examination, sensory testing, and/or reflex testing in patients undergoing 10-kHz SCS for treatment of PDN. In summary, the purpose of this review is to equip provider with important updates on the use of neuromodulation interventions for the treatment of PDN that is refractory to conventional medical therapy, with current level I evidence supporting use of 10-kHz and tonic SCS for PDN.

Intermittent Dorsal Root Ganglion Stimulation Is as Efficacious as Standard Continuous Dosing in Treating Chronic Pain: Results From a Randomized Controlled Feasibility Trial

IntroductionDorsal root ganglion stimulation (DRG-S) is a form of neuromodulation used to treat chronic pain. A spinal cord stimulation (SCS) method with paresthesia-free waveform used in the dorsal columns, burst-SCS, recently demonstrated efficacy using intermittent stimulation, where stimulation is cycled on and off for set durations. Tonic SCS is a paresthesia-based therapy that is ineffective at sub-perception levels and when delivered in a cycled manner. DRG-S also uses a tonic waveform, yet unlike tonic SCS, it is effective at sub-perception levels. This study aimed to determine whether the cycling of stimulation at the DRG could maintain DRG-S efficacy. Materials and MethodsThis study followed a prospective, randomized, and balanced, double-blinded (assessor) protocol. Twenty DRG-S responders were randomized to a sequence of three programs for consecutive two-week intervals: continuous stimulation; 1 minute on:1 minute off; or 1 minute on:2 minutes off. The primary outcome of this study was change in pain ratings with the cycled programs compared with continuous stimulation. Secondary outcomes included changes in function and scores for quality of life, and stimulation program preference. ResultsMean scores were similar at the end of each two-week stimulation program for Numerical Rating Scale pain (continuous = 2.9 ± 0.8, 1:1 on-off = 2.6 ± 0.7, and 1:2 on-off = 2.7 ± 0.7 cm, p = 0.39), disability (p = 0.72), and general health (p = 0.95). No clinically significant differences were found from the upper boundaries of the 95% confidence intervals of the mean difference in pain, disability, and general health for each intermittent stimulation program vs the continuous program. At the end of the study, the continuous stimulation, 1:1 on-off dosing, and 1:2 on-off dosing programs were preferred by a similar number of patients. ConclusionsIntermittent DRG-S produces comparable results to continuous stimulation over a two-week period. Intermittent delivery may extend battery life and facilitate a smaller implantable pulse generator.

Tonic, Burst, and Burst-Cycle Spinal Cord Stimulation Lead to Differential Brain Activation Patterns as Detected by Functional Magnetic Resonance Imaging

ObjectiveThe objective of this preclinical study was to examine the responses of the brain to noxious stimulation in the presence and absence of different modes of spinal cord stimulation (SCS) using blood-oxygen-level-dependent functional magnetic resonance imaging (BOLD-fMRI). Materials and MethodsSprague-Dawley rats were randomized to groups based on the mode of SCS delivered which included tonic stimulation (n = 27), burst stimulation (n = 30), and burst-cycle stimulation (n = 29). The control (sham) group (n = 28) received no SCS. The SCS electrode was inserted between T10 and T12 spinal levels prior to fMRI session. The experimental protocol for fMRI acquisition consisted of an initial noxious stimulation phase, a treatment phase wherein the SCS was turned on concurrently with noxious stimulation, and a residual effect phase wherein the noxious stimulation alone was turned on. The responses were statistically analyzed through paired t-test and the results were presented as z-scores for the quantitative analysis of the fMRI data. ResultsThe treatment with different SCS modes attenuated the BOLD brain responses to noxious hindlimb stimulation. The tonic, burst, and burst-cycle SCS treatment attenuated BOLD responses in the caudate putamen (CPu), insula (In), and secondary somatosensory cortex (S2). There was little to no corresponding change in sham control in these three regions. The burst and burst-cycle SCS demonstrated greater attenuation of BOLD signals in CPu, In, and S2 compared to tonic stimulation. ConclusionThe high-resolution fMRI study using a rat model demonstrated the potential of different SCS modes to act on several pain-matrix-related regions of the brain in response to noxious stimulation. The burst and burst-cycle SCS exhibited greater brain activity reduction in response to noxious hindlimb stimulation in the caudate putamen, insula, and secondary somatosensory cortex compared to tonic stimulation.

Spinal cord stimulation for neuropathic pain.

Spinal cord stimulation (SCS) is used for more than 40years to treat localized chronic medically refractory neuropathic pain involving limb(s) and trunk. The most frequent indications remain complex regional pain syndrome (CRPS) failed back surgery syndrome (FBSS), and peripheral neuropathy. Stimulation-induced paresthesias, perceived by the patient, prevent blinded evaluation and increase the placebo effect, decreasing the credibility of the tonic SCS efficacy. Retrospective studies reported that about 50% of the patients are improved more than 50% at short-term, but long-term improvement is less. Several comparative randomized trials (RCT) are now available. In CRPS, a RCT demonstrated the superiority of SCS plus physiotherapy compared to physiotherapy alone. In FBSS, two RCTs have shown that SCS was superior to reoperation and conventional medical treatment, (CMM) respectively. New stimulation waveforms, namely burst, high frequency (10KHz) stimulation and close-loop SCS, have been proposed recently to avoid the perception of paresthesias and/or increase the pain relief. RCTs in FBSS have suggested that these new SCS modalities were as least as efficient than conventional tonic SCS and perhaps slightly superior. Two RCTs confirmed SCS efficacy in painful diabetic neuropathy in comparison with CMM. Complications are frequent (hardware dysfunction or migration, superficial infection) but exceptionally serious. Consequently, the risk/benefit ratio is favorable to SCS, considering that chronic pain patients undergoing this procedure are usually resistant to all the other therapies.

Modulation of the Somatosensory Evoked Potential by Attention and Spinal Cord Stimulation.

Introduction: Spinal Cord Stimulation (SCS) is a last-resort treatment for patients with intractable chronic pain in whom pharmacological and other treatments have failed. Conventional tonic SCS is accompanied by tingling sensations. More recent stimulation protocols like burst SCS are not sensed by the patient while providing similar levels of pain relief. It has been previously reported that conventional tonic SCS can attenuate sensory-discriminative processing in several brain areas, but that burst SCS might have additional effects on the medial, motivational-affective pain system. In this explorative study we assessed the influence of attention on the somatosensory evoked brain responses under conventional tonic SCS as well as burst SCS regime.Methods: Twelve chronic pain patients with an implanted SCS device had 2-weeks evaluation periods with three different SCS settings (conventional tonic SCS, burst SCS, and sham SCS). At the end of each period, an electro-encephalography (EEG) measurement was done, at which patients received transcutaneous electrical pulses at the tibial nerve to induce somatosensory evoked potentials (SEP). SEP data was acquired while patients were attending the applied pulses and while they were mind wandering. The effects of attention as well as SCS regimes on the SEP were analyzed by comparing amplitudes of early and late latencies at the vertex as well as brain activity at full cortical maps.Results: Pain relief obtained by the various SCS settings varied largely among patients. Early SEP responses were not significantly affected by attention nor SCS settings (i.e., burst, tonic, and sham). However, late SEP responses (P300) were reduced with tonic and burst SCS: conventional tonic SCS reduced P300 brain activity in the unattended condition, while burst SCS reduced P300 brain activity in both attended and unattended conditions.Conclusion: Burst spinal cord stimulation for the treatment of chronic pain seems to reduce cortical attention that is or can be directed to somatosensory stimuli to a larger extent than conventional spinal cord stimulation treatment. This is a first step in understanding why in selected chronic pain patients burst SCS is more effective than tonic SCS and how neuroimaging could assist in personalizing SCS treatment.

High‐frequency spinal cord stimulation as rescue therapy for chronic pain patients with failure of conventional spinal cord stimulation

This study aims to evaluate the efficacy of 10-kHz high-frequency (HF10) devices as a rescue treatment in patients with failure of conventional spinal cord stimulation (SCS) therapy for chronic pain without the need to change the spinal hardware. In this real-world prospective study, patients with neuropathic pain treated with conventional tonic SCS in whom the therapy had failed, either during the trial phase or after a period of optimal functioning, were recruited throughout 2years for HF10-SCS therapy. Data on analgesia, functionality, analgesics use and treatment safety were collected 12months after treatment. Eleven of the 18 (61%) patients included in the study were successfully rescued with HF10-SCS. Of them, 5 out of 12 (45%) were in the trial phase and six out of six (100%) had previously functioning implants. A significant improvement in low-back and limb pain was obtained (p=0.003 and p=0.0001, respectively). Treatment success was significantly associated with gender (p=0.037), weight (p=0.014), body mass index (BMI) (p=0.007) and time of rescue (p=0.015). A linear regression test confirmed a significant association between treatment failure and BMI and gender (p=0.004). Our results suggest that analgesic rescue with HF10-SCS is an effective therapeutic option for non-responders to conventional SCS, although obesity might be a limiting factor for treatment success. Nevertheless, more comprehensive studies are needed to corroborate our findings. This study shows that high-frequency stimulation may be useful in patients with failure of conventional tonic stimulation for chronic pain, both in the trial phase and in previously implanted subjects. The novelty of this study lies in the use of the implanted epidural electrodes, which avoids the need for further surgery. The results in terms of pain control and recovery of functionality are satisfactory. In addition, variables such as male gender and high body mass index could be predictors of therapy failure.

Analgesic Efficacy of “Burst” and Tonic (500 Hz) Spinal Cord Stimulation Patterns: A Randomized Placebo-Controlled Crossover Study

ObjectiveSThe aim of this study was to compare the efficacy in reducing pain intensity in adult subjects suffering from chronic back and leg pain of burst (BST) and tonic sub-threshold stimulation at 500 Hz (T500) vs. sham stimulation delivered by a spinal cord stimulation (SCS) device capable of automated postural adjustment of current intensity. Materials and MethodsA multicentre randomized double-blind, three-period, three-treatment, crossover study was undertaken at two centers in the United Kingdom. Patients who had achieved stable pain relief with a conventional SCS capable of automated postural adjustment of current intensity were randomized to sequences of BST, T500, and sham SCS with treatment order balanced across the six possible sequences. A current leakage was programmed into the implantable pulse generator (IPG) in the sham period. The primary outcome was patient reported pain intensity using a visual analog scale (VAS). ResultsNineteen patients were enrolled and randomized. The mean reduction in pain with T500 was statistically significantly greater than that observed with either sham (25%; 95% CI, 8%–38%; p = 0.008) or BST (28%; 95% CI, 13%–41%; p = 0.002). There were no statistically significant differences in pain VAS for BST versus Sham (5%; 95% CI, −13% to 27%; p = 0.59). Exploratory sub-group analyses by study site and sex were also conducted for the T500 vs. sham and BST versus sham comparisons. ConclusionsThe findings suggest a superior outcome versus sham from T500 stimulation over BST stimulation and a practical equivalence between BST and sham in a group of subjects with leg and back pain habituated to tonic SCS and having achieved a stable status with stimulation.

Stanford Pragmatiec Effectiveness Comparison (SPEC) protocol: Comparing long-term effectiveness of high-frequency and burst spinal cord stimulation in real-world application

ObjectivesHigh-frequency and burst stimulation are newer waveforms that have demonstrated promise compared to traditional tonic spinal cord stimulation (SCS), but more studies are needed to compare their effectiveness. We report the study methods for an ongoing, single center, pragmatic randomized clinical trial to compare the effectiveness of high-frequency and burst SCS in patients with chronic back and/or leg pain. Materials and methodsParticipants who are candidates for spinal cord stimulation are enrolled and screened. Participants will be randomly assigned using point-of-care randomization to receive either high-frequency or burst SCS. Data collection will be through Stanford Pain Management Center's learning healthcare system: CHOIR. CHOIR surveys include National Institutes of Health Patient Reported Outcomes Measurement Information System item banks, a body map, questions about pain intensity, pain catastrophizing scale, and questions about patients' pain experience and healthcare utilization. Participants will complete online surveys at baseline and then 1, 3, 6, 12, 18, 24 and 36 months after their device implant. All participants will use our routine process of trial and implant. Reported adverse events are monitored throughout the study. Our primary outcome is change from baseline in pain intensity at 12 months. ResultsWe hypothesize that high-frequency SCS is more effective than burst SCS in improving pain, physical function and pain interference in participants with chronic low back and/or leg pain. ConclusionsThe pragmatic nature of our proposed trial enables us to recruit a larger participant cohort faster and to follow up these participants longer than currently published clinical trials.

Neuromodulation With Burst and Tonic Stimulation Decreases Opioid Consumption: A Post Hoc Analysis of the Success Using Neuromodulation With BURST (SUNBURST) Randomized Controlled Trial

ObjectivesThe SUNBURST study was a prospective, multicenter, randomized crossover trial of a single device delivering burst and tonic spinal cord stimulation (SCS) for chronic trunk and/or limb pain. We performed a post hoc analysis of opioid consumption at baseline and after device implantation. Materials and MethodsAfter implantation, 100 patients were randomized to one mode (tonic or burst) for 12 weeks, and the other mode for the subsequent 12 weeks. After the crossover period (24 weeks), patients chose their preferred mode and were assessed for one year. We analyzed 69 patients who took opioid medication at baseline. The primary endpoint was opioid consumption in morphine milligram equivalents (MMEs) at baseline and 12 months postimplantation. Subgroup analysis included opioid consumption based on Center for Disease Control markers (<50, 50–90, 90–120, >120 MME/day) and stimulation mode preference. ResultsOpioid consumption at 12 months was lower compared to baseline (53.94 vs. 79.19 MME, MD −25.25, 95% CI −43.77 to 6.73, p = 0.008). By 12 months, 11 of 69 patients (15.9%) discontinued all opioid (p = 0.001). Based on CDC dose markers, the proportion of patients taking >120 MME/day decreased by 61.7% at 12 months postintervention compared to baseline (p = 0.043). Forty-five of 69 patients (65.2%) preferred burst SCS while 15 of 69 patients (21.7%) preferred tonic SCS (p < 0.001). ConclusionA device delivering tonic and burst SCS was associated with decreased opioid consumption after 12 months in patients with chronic trunk and/or limb pain. The proportion of patients reporting the highest opioid intake (>120 MME/day) decreased to a lower CDC dose category by 61.7%, carrying important implications for those at highest risk for opioid-related substance use disorder, overdose, and death.

Tonic, Burst, High-Density, and 10-kHz High-Frequency Spinal Cord Stimulation: Efficiency and Patients' Preferences in a Failed Back Surgery Syndrome Predominant Population. Review of Literature

Spinal cord stimulation (SCS) is a neuromodulation process to treat neuropathic pain, initially developed on tonic paresthesia-based stimulation. In the last decade, 3 major paresthesia-free SCSs have emerged. Several studies show their superiority over tonic stimulation. We summarize the data on SCS efficacy and patients' preferences. We selected studies from the last decade to clarify whether the different paresthesia-free SCSs are superior to tonic or not and for which SCS the patient has a preference. Study selection was focused on a failed back surgery syndrome predominant population. SCS is an effective way to treat intractable neuropathic pain of the limbs and back, compared with conventional medical management and reoperation. Paresthesia-free SCSs as burst, high-density, and 10-kHz frequency are equal to tonic SCS in some studies and superior in most. Analysis of patients' preferences shows a clear trend toward paresthesia-free SCS. Recent studies show superiority of paresthesia-free SCS compared with tonic SCS and those results are corroborated by analysis of patients' preferences. Taking these data into account should motivate physicians to opt for multimodal capable devices before implanting SCS.

14. Nonlinear burst spinal cord stimulation can attenuate pain and catastrophizing in patients with persistent back pain and high psychological distress

BACKGROUND CONTEXT Psychological factors such as depression, anxiety, and poor coping strategies have been shown to predict negative outcomes after lumbar spine surgery and spinal cord stimulation (SCS). Recent studies have shown that nonlinear burst spinal cord stimulation (NLB-SCS), compared with traditional low-frequency tonic SCS, produces a greater effect on brain targets associated with the affective/emotional aspects of pain processing via the modulation of the medial spinothalamocortical pathways. PURPOSE Herein we present outcomes after NLB-SCS in patients with persistent back pain after lumbar spine surgery who are suffering from high psychological distress. STUDY DESIGN/SETTING Subanalysis from a prospective, multicenter, international, single arm study on nonlinear burst spinal cord stimulation. PATIENT SAMPLE Data for this subanalysis were extracted from an ongoing prospective, multicenter, study on NLB-SCS (ClinicalTrials.gov NCT03082261). OUTCOME MEASURES Catastrophizing Scale (PCS), Patient Health Questionnaire Depression scale (PHQ-9), State Trait Anxiety Index (STAI), Numerical Rating Scale (NRS). METHODS One-year outcomes were evaluated in subjects who presented with severe symptoms at baseline on the Pain Catastrophizing Scale (PCS), Patient Health Questionnaire Depression scale (PHQ-9), or State Trait Anxiety Index (STAI). Severity and responder analyses were performed for each measure, based on individually published standards. Severe symptoms were classified as scores of ≥30 on the PCS, ≥10 on the PHQ-9, and ≥40 on the STAI. Responders were classified as subjects who reported below these severity thresholds. Additional outcomes assessed at the 12-month follow-up visit included the Numeric Pain Rating Scale (NRS) and the EuroQol 5-Dimensions (EQ-5D). The minimal clinical important difference (MCID) for the EQ-5D Index is a 0.074 increase. RESULTS At baseline, 107 subjects reported severe symptoms of anxiety (64%), depression (52%), or catastrophizing (37%). Thirty-six percent reported severe symptoms in all three measures. At one-year post-implant, 69% were no longer catastrophizing, 50% were no longer clinically depressed, and 44% responded on STAI. Moreover, quality of life on EQ-5D improved on average from 0.38 before therapy to 0.62 post-therapy. Pain intensity was significantly decreased at 12 months; 77% reported at least 50% pain relief. CONCLUSIONS Our results demonstrate that NLB-SCS is an effective therapy for patients with persistent back pain who are suffering from high psychological distress. Subjects reported improvements across all psychological measures, reaffirming that NLB-SCS modulates the affective/emotional aspects of pain processing. FDA DEVICE/DRUG STATUS Spinal cord stimulation (Approved for this indication)