Burst Spinal Cord Stimulation Research Articles

O084 / #701 NEUROSTIMULATION IS AN EFFECTIVE TREATMENT OPTION FOR CHRONIC BACK PAIN REGARDLESS OF PRIOR SPINAL SURGERY: TRACK 3: NEUROSTIMULATION FOR BACK AND LEG PAIN

Low back pain (LBP) has been one of the leading causes of disability worldwide for the past 30 years. Spinal cord stimulation (SCS) is a minimally invasive and reversible therapy, demonstrating increasing efficacy for the treatment of chronic pain when used earlier in the treatment algorithm. Despite this, SCS is frequently considered a last-line therapy option, often following surgical intervention. Here, we assess the outcomes of passive recharge burst SCS in surgically naïve subjects and those with persisting pain post-surgery.

Epidural Laterality and Pain Relief With Burst Spinal Cord Stimulation

IntroductionBurst spinal cord stimulation (SCS) can achieve excellent clinical reduction of pain, alongside improvements in function, quality of life, and related outcomes. Good outcomes likely depend on good lead placement, thereby enabling recruitment of the relevant neural targets. Several competing approaches exist for lead implantation, such as the use of single vs bilateral leads and leads lateralized vs placed at midline. The objective of this study was to examine the relationship between paresthesia locations and pain relief with burst SCS in a prospective double-blind crossover design. Materials and MethodsAll participants had bilateral back and leg pain, with more intense pain experienced on one side of the body. A trial SCS system was placed, during which brief intraoperative mapping with conventional stimulation was used to characterize paresthesia locations. Two programs for subperception burst SCS treatment were then applied for two days each, in random order: bilateral paresthesia coverage vs unilateral paresthesia coverage contralateral to the side of the body with more intense pain. Pain ratings (visual analog scale [VAS]) and pain reductions (scaling pain relief [SPR]) were reported for each. ResultsOf the 30 participants who completed the study, 24 (80%) had good pain relief with at least one program. A baseline VAS score of 8.75 was reduced to 5.98 with contralateral stimulation and to 2.88 with bilateral stimulation; with SPR, this equated to 31.25% and 67.50% improvement, respectively. The incremental benefit of bilateral stimulation over contralateral stimulation was statistically significant (p < 0.001). Of the 24 participants, 87.5% preferred bilateral stimulation, whereas 12.5% preferred unilateral stimulation. The six participants who failed the trial had no preference. DiscussionWhen burst stimulation is delivered to spinal targets that can generate paresthesias contralateral to the side of worst pain, suboptimal therapy is achieved. Thus, attention to laterality and pain coverage is critical for successful therapy, and it may be important to carefully consider lead implantation techniques.

Study protocol: Effects of active versus passive recharge burst spinal cord stimulation on pain experience in persistent spinal pain syndrome type 2: a multicentre randomized trial (BURST-RAP study)

BackgroundSpinal cord stimulation (SCS) has shown to be an effective treatment for patients with persistent spinal pain syndrome type 2 (PSPS Type 2). The method used to deliver electrical charge in SCS is important. One such method is burst stimulation. Within burst stimulation, a recharge pattern is used to prevent buildup of charge in stimulated tissues. Two variations of burst waveforms are currently in use: one that employs active recharge and one that uses passive recharge. It has been suggested that differences exist between active and passive recharge paradigms related to both efficacy of pain relief and their underlying mechanism of action. Active recharge has been shown to activate both the medial spinal pathway, engaging cortical sensorimotor areas involved in location and intensity of pain, and lateral pathway, reaching brain areas involved with cognitive-emotional aspects of pain. Passive recharge has been suggested to act via modulation of thalamic neurons, which fire in a similar electrical pattern, and thereby modulate activity in various cortical areas including those related to motivational and emotional aspects of pain. The objective of this randomized clinical trial is to assess and compare the effect of active versus passive recharge Burst SCS on a wide spectrum of pain in PSPS Type 2 patients.MethodsThis multicentre randomized clinical trial will take place in 6 Dutch hospitals. PSPS Type 2 patients (n=94) will be randomized into a group receiving either active or passive recharge burst. Following a successful trial period, patients are permanently implanted. Patients complete the Pain Catastrophizing Scale (PCS) (primary outcome at 6 months), Numeric Pain Rating Scale (NRS), Patient Vigilance and Awareness Questionnaire (PVAQ), Hospital Anxiety and Depression Scale (HADS), Quality of Life (EQ-5D), Oswestery Disability Index (ODI), Patient Global Impression of Change (PGIC) and painDETECT questionnaires (secondary outcomes) at baseline, after trial, 1, 3, 6 and 12 months following implantation.DiscussionThe BURST-RAP trial protocol will shed light on possible clinical differences and effectivity of pain relief, including emotional-motivational aspects between active and passive burst SCS in PSPS Type 2 patients.Trial registrationClinicalTrials.gov registration: NCT05421273. Registered on 16 June 2022. Netherlands Trial Register NL9194. Registered on 23 January 2021.

226. Surgical treatment of refractory low back pain using implanted BurstDR spinal cord stimulation (SCS) in a cohort of patients without options for corrective surgery: findings and results from the DISTINCT study, a prospective randomized multi-center controlled trial

226. Surgical treatment of refractory low back pain using implanted BurstDR spinal cord stimulation (SCS) in a cohort of patients without options for corrective surgery: findings and results from the DISTINCT study, a prospective randomized multi-center controlled trial

ID:16446 Utilizing Intraoperative Neuromonitoring to Program Multiple Areas of BurstDR SCS for Treatment of Chronic Pain

Burst spinal cord stimulation (SCS) has demonstrated superior relief from overall pain and a reduction in back and leg pain compared to traditional tonic neurostimulation therapies. However, nearly 80% of patients have 2 or more non-contiguous pain areas. This can affect the ability to effectively program stimulation and the long-term efficacy of therapy. Multiple BurstDR region programming is a new option to treat multi-site pain by interleaving stimulation at multiple areas along the spinal cord. This study aims to develop a method for programming SCS using EEG and EMG based biomarkers recorded via standard intraoperative neuromonitoring protocols.

ID:16593 Burst-SCS Placed at the T12 DRG to Treat Chronic Low Back and Leg Pain

Dorsal root ganglion stimulation (DRG-S) has been utilized in treating axial low back pain (LBP) with T12 lead placement. Unfortunately, patients are not candidates for the Proclaim DRG-S system if they cannot use the handheld patient controller or require routine truncal MRI exams. The aim of this report is to describe the use of a Burst spinal cord stimulation (Burst-SCS) system with leads placed at the DRG in two patients with contraindications for the DRG-S system.

Men and Women Respond Equally Well to Spinal Cord and Dorsal Root Ganglion Stimulation

ObjectivesThe influence of gender on outcomes in individuals undergoing treatment for chronic pain is unclear. This retrospective, single-site study explored the impact of gender on pain, quality of life (QoL), revisions, and explants in patients with failed back surgery syndrome or visceral pain, who received a fully implanted 10 kHz spinal cord stimulation (SCS), burst SCS, or dorsal root ganglion (DRG) stimulation system. Materials and MethodsThe following data were collected from paper and electronic records: gender, age, chronic pain diagnosis, system, baseline and follow-up scores (average pain [visual analog scale, VAS], worst pain [VAS], QoL [EQ-5D-3L]), revisions, and explants. Data were statistically analyzed by one-way ANCOVAs controlling for age, chi-square tests of independence, and logistic regression. ResultsThe final sample comprised 387 patients (176 males and 211 females). Males were significantly older compared to females (mean difference: 2.33 years, p = 0.044). Controlling for age, baseline average pain was significantly lower in males than females (mean difference: −0.32, p = 0.049). Males and females responded equally well to 10 kHz SCS and burst SCS as well as DRG stimulation. A greater percentage of males (5%) than females (1%) had revisions due to lead fractures. Additionally, more females (13%) than males (6%) had an explant due to insufficient pain relief. Female gender and older age were associated with greater likelihood of having an explant compared to male gender and younger age. ConclusionGender may play an influential role in pain severity at baseline but have little effect at follow-up. To help identify which patients may undergo a revision or explant, gender and age could be important factors and should be further scrutinized. Even though men and women responded equally well to SCS and DRG stimulation, more men had a revision due to lead fractures, and more women were explanted due to insufficient pain relief.

Burst Spinal Cord Stimulation in Pregnancy: First Clinical Experiences

ObjectivesSpinal cord stimulation (SCS) is a treatment for chronic neuropathic pain. It is based on the delivery of electric impulses to the spinal cord, traditionally in a regular square-wave pattern (“tonic” stimulation) and, more recently, in a rhythmic train-of-five “BurstDR” pattern. The safety of active SCS therapy in pregnancy is not established, and recommendations are based on limited casuistic evidence. We present in this study clinical data on a case series of six women treated with burst SCS during pregnancy. In addition, we present the ultrasonographic flow measurements of fetal and uteroplacental blood flow in a pregnant patient. Materials and MethodsPatients were included if they had been implanted with a full SCS system at Aarhus University Hospital, Denmark, between 2006 and 2020 and received active burst SCS stimulation during a pregnancy. Telephone interviews were conducted, including details on SCS therapy, medication, pregnancy course and outcome, and health status of the offspring. In one patient, the uteroplacental and fetal blood flow was assessed in gestational week 29 by Doppler flow measurements performed during both ON and OFF phases of the SCS system. ResultsSix patients were included with a total of 11 pregnancies. Three pregnancies ended in miscarriages, all in the same patient who had preexisting significant risk factors for miscarriage. Eight resulted in a live-born child with normal birth weight for gestational age; seven were born at term, and one was born late preterm, in gestational week 36. Ultrasonographic Doppler flow, measured in one patient, was normal and did not reveal any immediate changes between burst SCS ON and OFF. Seven children were reported healthy with normal neurodevelopment and one physically healthy but with developmental delays. ConclusionsThe data presented in this study add to the accumulating evidence of the safety of SCS in pregnancy.

Burst Spinal Cord Stimulation in the Management of Chronic Pain: Current Perspectives.

Over the last several decades, opioid diversion, misuse, and over-prescription have run rampant in the United States. Spinal cord stimulation (SCS) has been FDA approved for treatment for a primary indication of neuropathic limb pain that is resistant to more conservative medical therapy. The disorders qualified for treatment include neuropathic, post-surgical, post-amputation, osteodegenerative, and pain related to vascular disease. Some of the most frequently cited conditions for treatment of SCS include failed back surgery syndrome, complex regional pain syndrome (CRPS) Type I and Type II, and post-herpetic neuralgias. Developments in SCS systems have led to the differentiation between the delivered electromechanical waveform patterns, including tonic, burst, and high-frequency. Burst SCS mitigates traditional paresthesia due to expedited action potential and offers improved pain relief. Burst SCS has been shown in available studies to be non-inferior to the traditional SCS, which can cause pain paresthesia in patients who already have chronic pain. Burst SCS does not seem to cause or need the paresthesia seen in traditional SCS, making SCS not tolerable to patients.Moreover, some studies suggest that burst SCS may decrease opioid consumption in patients with chronic pain. This can make burst SCS an extremely useful tool in the battle against chronic pain and the raging opioid epidemic. As of now, more research needs to be performed to further delineate the effectiveness and long-term safety of this device.

Successful management of segmental zoster paresis on the upper arm with temporally burst spinal cord stimulation

Segmental zoster paresis (SZP) of the limbs is characterized by a focal, asymmetric neurogenic weakness that may occur in an extremity affected by herpes zoster (HZ). In this case report, we describe the case of a patient with SZP who presented with these problems and responded well to temporary spinal cord stimulation (SCS) and systematic rehabilitation. A 62-year-old female patient was referred for right upper limb pain, weakness, and insomnia due to pain. After completing the 14-day trial stimulation, the pain numerical rating scale of the patient in the right upper extremity decreased from 8/10 to 2/10. The Athens insomnia scale score decreased from 15/24 to 10/24. Furthermore, the grip strength of the right hands increased from 6.7 to 16.8kg at discharge. We induced temporal SCS and rehabilitation of the right upper limb SZP and successfully reduced the pain. An in-depth understanding of the neurological complications secondary to HZ should be emphasized, with temporal SCS and rehabilitation expected to play a crucial role in the motor recovery of patients with SZP.

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.

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.

Comparison of Paresthesia Mapping With Anatomic Placement in Burst Spinal Cord Stimulation: Long-Term Results of the Prospective, Multicenter, Randomized, Double-Blind, Crossover CRISP Study

ObjectivesSpinal cord stimulation (SCS) is an effective therapy for chronic intractable pain. Conventional SCS involves electrode placement based on intraoperative paresthesia mapping; however, newer paradigms like burst may allow for anatomic placement of leads. Here, for the first time, we report the one-year safety and efficacy of burst SCS delivered using a lead placed with conventional, paresthesia mapping, or anatomic placement approach in subjects with chronic low back pain (CLBP). Materials and MethodsSubjects with CLBP were implanted with two leads. The first lead was placed to cross the T8/T9 disc and active contacts for this lead were chosen through paresthesia mapping. The second lead was placed at the T9/T10 spinal anatomic landmark. Subjects initially underwent a four-week, double-blinded, crossover trial with a two-week testing period with burst SCS delivered through each lead in a random order. At the end of trial period, subjects expressed their preference for one of the two leads. Subsequently, subjects received burst SCS with the preferred lead and were followed up at 3, 6, and 12 months. Pain intensity (visual analog scale), quality-of-life (EuroQol-5D instrument), and disability (Oswestry Disability Index) were evaluated at baseline and follow-up. ResultsForty-three subjects successfully completed the trial. Twenty-one preferred the paresthesia mapping lead and 21 preferred the anatomic placement lead. Anatomic placement lead was activated in one subject who had no preference. The pain scores (for back and leg) significantly improved from baseline for both lead placement groups at all follow-up time points, with no significant between-group differences. ConclusionsThis study demonstrated that equivalent clinical benefits could be achieved with burst SCS using either paresthesia mapping or anatomic landmark-based approaches for lead placement. Nonparesthesia-based approaches, such as anatomic landmark-based lead placement investigated here, have the potential to simplify implantation of SCS and improve current surgical practice.

Ultra-Low Energy Cycled Burst Spinal Cord Stimulation Yields Robust Outcomes in Pain, Function, and Affective Domains: A Subanalysis From Two Prospective, Multicenter, International Clinical Trials

IntroductionDeRidder's burst stimulation design has become a key spinal cord stimulation (SCS) waveform because it reduces the intensity of pain as well as its associated emotional distress. The brain pathways underlying these outcomes may also allow for the effects of stimulation to carry over after stimulation is turned off, making it amenable to intermittent application. Here, the utility of intermittently cycled burst was evaluated using data from two large real-world prospective studies (TRIUMPH, REALITY). Materials and MethodsSubjects used intermittent dosing in a 1:3 ratio (30 sec on, 90 sec off; N = 100) in TRIUMPH and 1:12 ratio in REALITY (30-sec on, 360-sec off; N = 95) for six months. Pain intensity (0–10 numeric rating scale), pain-related emotions on the pain catastrophizing scale (PCS), and physical function on PROMIS questionnaires were compared with preimplant baseline ratings and by group. ResultsIn both groups, mean pain intensity decreased by nearly 50% relative to baseline, PCS scores significantly decreased, and physical function improved. Importantly, no differences between the 1:3 and 1:12 groups were identified. A high proportion, 80% and 77% of the 1:3 and 1:12 groups, respectively, were considered responders on a multiple measures. No adverse events were associated with intermittent stimulation. DiscussionIntermittent cycling of burst SCS lowers the overall electric charge delivered to the spinal cord and preserves battery consumption, without compromising pain relief and associated symptoms.

Unilateral Lumbosacral Plexopathy Following Extra-Corporeal Membrane Oxygenation Managed with Burst Spinal Cord Stimulation: A Case Report

BACKGROUND: Lumbar plexopathy is considered a rare complication of minimally invasive endovascular or surgical procedures, but it has not been related to the use of extracorporeal membrane oxygenation (ECMO) so far. In cases of high-intensity neuropathic pain, neuromodulation should be considered early in the treatment. CASE REPORT: After receiving supportive ECMO therapy for 7 days, a 42-year-old woman developed lumbar plexopathy and high-intensity neuropathic pain and was referred to the pain unit 6 months later. After unsuccessful use of neuropathic drugs, spinal cord stimulation achieved global improvements of 90%. Sixteen months later, the patient continues to be asymptomatic, leading an active life as a mother of 4 children. CONCLUSIONS: The use of ECMO cannot be said to be the main cause of plexopathy in this case, but a multifactorial approach regarding this issue should be considered. Spinal cord stimulation can provide dramatic relief in localized neuropathic pain. KEY WORDS: Extracorporeal membrane oxygenation (ECMO), lumbosacral plexopathy, spinal cord stimulation

Passive Recharge Burst Spinal Cord Stimulation Provides Sustainable Improvements in Pain and Psychosocial Function: 2-year Results From the TRIUMPH Study.

Prospective, international, multicenter, single-arm, post-market study. The aim of this study was to assess long-term safety and effectiveness of spinal cord stimulation using a passive recharge burst stimulation design for chronic intractable pain in the trunk and/or limbs. Herein we present 24-month outcomes from the TRIUMPH study (NCT03082261). Passive recharge burst spinal cord stimulation (B-SCS) uniquely mimics neuronal burst firing patterns in the nervous system and has been shown to modulate the affective and attentional components of pain processing. After a successful trial period, subjects received a permanent SCS implant and returned for follow-up at 6, 12, 18, and 24 months. Significant improvements in physical, mental, and emotional functioning observed after 6 months of treatment were maintained at 2 years. Pain catastrophizing scale (PCS) scores dropped below the population norm. Health-related quality of life on EQ-5D improved across all domains and the mean index score was within one standard deviation of norm. Pain reduction (on NRS) was statistically significant (P < 0.001) at all timepoints. Patient reported pain relief, a stated percentage of improvement in pain, was consistent at all timepoints at 60%. Patients reported significant improvements across all measures including activity levels and impact of pain on daily life. At 24 months, 84% of subjects were satisfied and 90% would recommend the procedure. Subjects decreased their chronic pain medication intake for all categories; 38% reduced psychotropic and muscle relaxants, 46% reduced analgesic, anti-convulsant and NSAIDs, and 48% reduced opioid medication. Adverse events occurred at low rates without unanticipated events. Early positive results with B-SCS were maintained long term. Evidence across multiple assessment tools show that B-SCS can alleviate pain intensity, psychological distress, and improve physical function and health-related quality of life.Level of Evidence: 3.

Neural Recruitment During Conventional, Burst, and 10-kHz Spinal Cord Stimulation for Pain

Spinal cord stimulation (SCS) is a popular neurostimulation therapy for severe chronic pain. To improve stimulation efficacy, multiple modes are now used clinically, including conventional, burst, and 10-kHz SCS. Clinical observations have produced speculation that these modes target different neural elements and/or work via distinct mechanisms of action. However, in humans, these hypotheses cannot be conclusively answered via experimental methods. Therefore, we utilized computational modeling to assess the response of primary afferents, interneurons, and projection neurons to conventional, burst, and 10-kHz SCS. We found that local cell thresholds were always higher than afferent thresholds, arguing against direct recruitment of these local cells. Furthermore, although we observed relative threshold differences between conventional, burst, and 10-kHz SCS, the recruitment order was the same. Finally, contrary to previous reports, axon collateralization produced complex changes in activation thresholds of primary afferents. These results motivate future work to contextualize clinical observations across SCS paradigms. PerspectiveThis article presents the first computational modeling study to investigate neural recruitment during conventional, burst, and 10-kilohertz spinal cord stimulation for chronic pain within a single modeling framework. The results provide insight into these treatments’ unknown mechanisms of action and offer context to interpreting clinical observations.

Burst spinal cord stimulation can attenuate pain and its affective components in chronic pain patients with high psychological distress: results from the prospective, international TRIUMPH study

BACKGROUND CONTEXTPsychological characteristics such as catastrophizing and depression have been shown to negatively impact outcome prognosis after spinal interventions. PURPOSETo evaluate whether high psychological distress, defined as clinically elevated levels of catastrophizing and depression, is associated with poorer outcomes after spinal cord stimulation utilizing a passive recharge burst stimulation design. This proprietary waveform may uniquely attenuate the emotional aspects of chronic pain given its affects on the medial pain pathway projecting to the dorsal anterior cingulate cortex and anterior insula. STUDY DESIGN/SETTINGSData were extracted from the prospective, multi-center, single-arm, international TRIUMPH study. The purpose of TRIUMPH was to assess long-term (2 years) safety and effectiveness of spinal cord stimulation for chronic pain in the trunk and/or limbs using a passive recharge enabled burst spinal cord stimulation (B-SCS) system. PATIENT SAMPLETwo subsets of study patients were identified; those with (n=31) and those without (n=54) high psychological distress. OUTCOME MEASURESPsychological and functional outcomes as well as pain intensity and impact of pain on life were administered at baseline and all follow intervals. Additionally, patient satisfaction and patient global impression of change were assessed at all follow-up intervals. METHODSPsychological distress (PD) was defined as a baseline score of ≥ 30 on the Pain Catastrophizing Scale (PCS) and ≥ 10 on the Patient Health Questionnaire Depression scale (PHQ-9). Nondistressed (ND) patients had scores below these thresholds on both scales. All patients were implanted with a B-SCS system and completed data collection for the 24-month follow-up visit. This study was funded by Abbott. JMH is a consultant for Abbott and has received <$20,000 in lifetime consulting fees from Abbott. SMF is a consultant for Abbott and has received >$50,000 in lifetime consulting fees from Abbott. BB is an Abbott employee. RAC is a former Abbott employee. JJY is a consultant for Abbott and has received <$2,500 in lifetime consulting fees from Abbott. RESULTSOf the 128 participants with 24-month data, 31 (24%) and 54 (35%) met the criteria for PD and ND, respectively. Baseline measures indicated a more severe chronic pain profile and worse quality of life in the PD group. Two years after implant, 71% were no longer clinically catastrophizing and 58% were no longer clinically depressed. Notably, more than half of the PD patients on antidepressants discontinued or decreased their medication. Health-related quality of life was 82% higher in the PD group at 24 months, reaching levels similar to the ND group. Psychological distress did not impact outcomes after SCS therapy; composite multi-responder rates were similar in the 2 groups throughout the follow-up period. Patient reported pain relief (58% PD vs. 61% ND) was equivalent in each group. In both groups, 81% were satisfied or very satisfied with the pain relief provided. CONCLUSIONSOur results showed that B-SCS appears to be as effective in a chronic pain population with high psychological distress as in those without distress. This may be due to the unique mechanism of action with the stimulation design involving the emotional-affective medial pain pathway in the brain.

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.

Comparison of FDA-Approved Electrical Neuromodulation Techniques for Focal Neuropathic Pain: A Narrative Review of DRG, HF10, and Burst Neuromodulation

Evidence suggests that dorsal root ganglion stimulation (DRGS) is a more effective treatment for focal neuropathic pain (FNP) compared with tonic, paresthesia-based dorsal column spinal cord stimulation (SCS). However, new advancements in waveforms for dorsal column SCS have not been thoroughly studied or compared with DRGS for the treatment of FNP. The purpose of this review was to examine the evidence for these novel technologies; to highlight the lack of high-quality evidence for the use of neuromodulation to treat FNP syndromes other than complex regional pain syndrome I or II of the lower extremity; to emphasize the absence of comparison studies between DRGS, burst SCS, and high-frequency SCS; and to underscore that consideration of all neuromodulation systems is more patient-centric than a one-size-fits-all approach. This is a review article summarizing case reports, case series, retrospective studies, prospective studies, and review articles. The University of Miami, Florida. A literature search was conducted from February to March 2020 using the PubMed and EMBASE databases and keywords related to DRGS, burst SCS, HF10 (high-frequency of 10 kHz), and FNP syndromes. All English-based literature from 2010 reporting clinical data in human patients were included. Data for the treatment of FNP using burst SCS and HF10 SCS are limited (n = 11 for burst SCS and n = 11 for HF10 SCS). The majority of these studies were small, single-center, nonrandomized, noncontrolled, retrospective case series and case reports with short follow-up duration. To date, there are only 2 randomized controlled trials for burst and HF10 for the treatment of FNP. No studies were available comparing DRGS to HF10 or burst for the treatment of FNP. Data for the treatment of FNP using HF10 and burst stimulation were limited to a small sample size reported in mostly case reports and case series. FNP is a complex disease, and familiarity with all available systems allows the greatest chance of success.