Search

Spinal cord stimulators (SCS) are available with either primary cell (PC) or rechargeable cell (RC) batteries. Although RC systems are proposed to have a battery longevity upward of nine years, in comparison with four years for PC systems, there are few studies of longevity of SCS in the real world.This was an observational, nonrandomized, retrospective study of Medicare beneficiaries who received neurostimulator implants in the outpatient hospital. This study used Medicare fee-for-service claims data from 2013 to 2020. The clinical longevity of the implantable pulse generator (IPG), defined as the duration from implant until removal for any reason, was compared between PC and RC devices. Life distribution analysis was used to approximate device lifespan. The secondary analysis separated removals into explant or replacements. The statistics were adjusted for relevant clinical covariates.A total of 25,856 PC and 79,606 RC systems were included in the study. At seven years after implant, 53.8% of PC IPGs and 55.0% of RC IPGs remained in use. The life distribution modeling analysis projected a median lifespan of 8.2 years for PC and 9.0 years for RC devices. The rate of explant was lower for PC devices (19.2%) than for RC devices (22.0%, hazard ratio (HR) = 0.96, p = 0.082), whereas the rate of replacements was higher for PC devices (33.7%) than for RC devices (29.5%, HR = 1.31, p 0.001). An analysis of the battery type used in device replacements showed an increasing adoption of PC devices over time.This large, retrospective, real-world analysis of Medicare claims data demonstrated that the clinical longevity of neurostimulator devices is similar for PC and RC batteries. In the past, clinicians may have defaulted to RC devices based on the assumption that they provided extended battery life. Considering this longevity data, clinicians should now consider the choice between PC and RC devices based on other individual factors pertinent to the patient experience and not on purported longevity claims.

Introduction DeRidder'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 methods Subjects 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. Results In 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. Discussion Intermittent 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.

Chronic pain is debilitating and profoundly affects health-related quality of life. Spinal cord stimulation (SCS) is a well-established therapy for chronic pain; however, SCS has been limited by the inability to directly measure the elicited neural response, precluding confirmation of neural activation and continuous therapy. A novel SCS system measures the evoked compound action potentials (ECAPs) to produce a real-time physiological closed-loop control system.To determine whether ECAP-controlled, closed-loop SCS is associated with better outcomes compared with fixed-output, open-loop SCS at 24 months following implant.The Evoke study was a double-blind, randomized, controlled, parallel arm clinical trial with 36 months of follow-up. Participants were enrolled from February 2017 to 2018, and the study was conducted at 13 US investigation sites. SCS candidates with chronic, intractable back and leg pain refractory to conservative therapy, who consented, were screened. Key eligibility criteria included overall, back, and leg pain visual analog scale score of 60 mm or more; Oswestry Disability Index score of 41 to 80; stable pain medications; and no previous SCS. Analysis took place from October 2020 to April 2021.ECAP-controlled, closed-loop SCS was compared with fixed-output, open-loop SCS.Reported here are the 24-month outcomes of the trial, which include all randomized patients in the primary and safety analyses. The primary outcome was a reduction of 50% or more in overall back and leg pain assessed at 3 and 12 months (previously published).Of 134 randomized patients, 65 (48.5%) were female and the mean (SD) age was 55.2 (10.6) years. At 24 months, significantly more closed-loop than open-loop patients were responders (≥50% reduction) in overall pain (53 of 67 [79.1%] in the closed-loop group; 36 of 67 [53.7%] in the open-loop group; difference, 25.4% [95% CI, 10.0%-40.8%]; P = .001). There was no difference in safety profiles between groups (difference in rate of study-related adverse events: 6.0 [95% CI, -7.8 to 19.7]). Improvements were also observed in health-related quality of life, physical and emotional functioning, and sleep, in parallel with opioid reduction or elimination. Objective neurophysiological measurements substantiated the clinical outcomes and provided evidence of activation of inhibitory pain mechanisms.ECAP-controlled, closed-loop SCS, which elicited a more consistent neural response, was associated with sustained superior pain relief at 24 months, consistent with the 3- and 12-month outcomes.

Timothy R Deer,1 Douglas P Beall,2 Steven M Falowski3 1The Spine and Nerve Center of The Virginias, Charleston, WV 25301, USA; 2Comprehensive Specialty Care, Edmond, OK, 73103, USA; 3Argires Marotti Neurosurgical Associates of Lancaster, Lancaster, PA 17601, USACorrespondence: Steven M Falowski, Argires Marotta Neurosurgical Associates of Lancaster, Lancaster, PA, 17601, USA, Tel +1 717-358-0800, Email sfalowski@gmail.com

Steven M Falowski,1 Vipul Mangal,2 Jason Pope,3 Anish Patel,4 Mark Coleman,5 Dan Kendall,6 Richard Brouillette,7 Michael A Fishman8 1Neurosurgical Associates of Lancaster, Lancaster, PA, USA; 2National Spine and Pain, National Harbor, MD, USA; 3Evolve Restoration, Santa Rosa, CA, USA; 4National Spine and Pain, Frederick, MD, USA; 5National Spine and Pain, Pikesville, MD, USA; 6National Spine and Pain, McLean, VA, USA; 7National Spine and Pain, White Plains, MD, USA; 8Center for Interventional Pain and Spine, Lancaster, PA, USACorrespondence: Steven M FalowskiDirector Functional Neurosurgery, Neurosurgical Associates of Lancaster, 160 N Pointe Blvd Suite 200, Lancaster, PA, 17601, USATel +1 717-358-0800Email sfalowski@gmail.comIntroduction: Several treatment options exist for those with spinal stenosis, as well as degenerative changes. This series evaluates the use of an interspinous fixation (ISF) device as performed by interventional pain physicians.Methods: This is a retrospective analysis identifying 32 patients with the diagnosis of lumbar degenerative disc disease with secondary diagnosis of lumbar spinal stenosis being treated with ISF with Aurora Spine Zip Interspinous Spacer. Serious adverse events, specifically nerve injury, hematoma, infection, and death, were analyzed quantitatively for reported complications within 90 days from the procedure. In addition, VAS was analyzed for patient reported outcomes.Results: Adverse event rate was 0% with no incidences of reoperation, or device removal. Estimated blood loss was recorded as less than 50 cc for all patients. The preoperative pain assessment demonstrated an average pain score of 8.1 and a postoperative pain score of 2.65 equating to a percentage pain reduction of 67%.Conclusion: This case series demonstrates the success and safety of ISF being performed by interventional pain physicians in an outpatient setting. It is a valuable tool in the treatment of moderate to severe lumbar spinal stenosis and degenerative disc disease that has decreased morbidity and significant efficacy.Keywords: interspinous spacer, indirect decompression, interspinous fusion, interspinous fixation, lumbar degenerative disc disease, spinal stenosis, lumbar stenosis, spinal fusion

Multidisciplinary patient-reported outcomes are a critical part of assessing patients to better understand their well-being during treatment. The use of multidisciplinary patient-reported outcomes is recommended in many areas of medicine. The Patient-Reported Outcomes Measurement Information System-29 (PROMIS-29) has been utilized as a common measurement language across universally relevant domains, including pain, mood, sleep, social participation, and function. Retrospective analysis of prospectively collected data was performed. Subjects were identified and consecutively enrolled upon entry into chronic pain centers across 24 sites in the United States. The PROMIS-29 v2.1 and the numerical rating scale (NRS) were recorded. The pain impact score and the Health Utilities Index Mark 3 (HUI-3) were calculated. Statistical differences were assessed between genders and among age groups comprising subjects less than 40, 41–60, 61–80, and over 80 years of age. A total of 19,546 patients were assessed over the enrollment period from 2018 to 2020. The PROMIS-29 v2.1 was evaluated across the seven domains, along with the numerical rating sale (NRS). The mean scores of the population for PROMIS SF v1.0 Pain Interference 4a, PROMIS SF v1.0 Sleep Disturbance 4a, PROMIS SF v1.0 Fatigue 4a, PROMIS SF v1.0 Anxiety 4a, PROMIS SF V1.0 Depression 4a, PROMIS SF v2.0 Ability to Participate in Social Roles and Activities 4a, and PROMIS SF v1.0 Physical Function 4a, measuring pain interference, sleep disturbance, fatigue, anxiety, depression, social participation, and physical function, were 64.61, 57.19, 58.50, 53.94, 54.45, 40.06, and 36.23, respectively. Pain intensity was 6.38 on an 11-point NRS scale. The pain impact score (PIS) and health utilities index mark 3 (HUI-3) scores, calculated across the designated age groups, were 33.19 and 0.67, respectively. Statistical differences were observed for the domains of sleep disturbance and physical function for age groups less than 40 and greater than 80 years of age. This data set is the first published normative data set describing the PROMIS-29 assessment in the chronic pain population. The patient population is more homogeneous than expected, and females were found to have higher levels of dysfunction.

Despite minimally invasive techniques for sacroiliac joint fixation, clinical challenges remain. The investigators hypothesized the studied technique will transfix the sacroiliac joint to a level comparable to the intact sacroiliac joint.The study objective was to determine the dynamic stability of a square inter-joint implant using a triangular notch in opposing bone segments spanning the joint space.Stability was assessed by measuring micromotion using contralaterally placed transducers spanning the sacroiliac joint of a specimen during cyclic loading.A porcine in-vitro model was equipped with micromotion transducers on the intact and surgically implanted sacroiliac joint. Cyclic loading was applied on the L4 vertebra and the recorded micromotion data at each sacroiliac joint was analyzed.Porcine specimens from L3 to the sacrum including the pelvic ring were used to biomechanically evaluate the implantation technique. A novel technique consisting of a square inter-joint implant was placed so as to create a triangular stabilization notch within adjacent boney components of the sacroiliac joint. Displacement transducers were placed across implanted and contralateral porcine sacroiliac joint. Specimens were subjected to compressive loading between -10N and -100N followed by bending/rotation between 0.4Nm and 4.0Nm. Tests were conducted at 0.5Hz for 200 cycles. For each loading mode, transducer deflections (or rotations) were averaged at five-cycle intervals. Student's t-tests were used to compare fitted parameters between implanted and intact sacroiliac joint.In compression, implanted SIJ displayed reduced deflection compared to intact sacroiliac joint (P0.0001). In bending/rotation, initial rotation for the intact sacroiliac joint was increased compared to implanted sacroiliac joint (P0.0001). The computed Half-Life parameter represents the number of cycles at which the initial rotation decreases by 50% and was found to be statistically reduced for implanted sacroiliac joint as compared to intact sacroiliac joint.The use of porcine specimens resulted in uniform and good quality bone purchase. Further study may be required to evaluate the technique in older patients where bone quality is reduced.Compared to the intact sacroiliac joint, the implant and procedure in this study demonstrated decreased motion under cyclic compression. Under rotation, the implanted sacroiliac joint displayed increased initial stability that subsequently normalized to intact sacroiliac joint values.

Introduction The sacroiliac joint (SIJ) has been estimated to contribute to pain in as much as 38% of cases of lower back pain. There are no clear diagnostic or treatment pathways. This article seeks to establish a clearer pathway and algorithm for treating patients.

Background and Objectives Multiple variables play a role in spinal cord stimulation (SCS) treatment outcomes, including patient anatomy, pain pattern, lead location, stimulation parameters, and so on. A wide range of stimulation parameters are considered safe and on‐label, and as a result a growing number of new frequencies and frequency‐combinations are being incorporated into standard practice. A standardized approach to therapy delivery may provide more consistent outcomes for more patients. The Vectors study evaluated whether there is significant sustained improvement in pain and functional outcomes when therapy is delivered using a standardized approach. Materials and Methods Vectors, a post‐market, single‐arm study evaluated the safety and efficacy of SCS with an implantable neurostimulator starting with 1 kHz stimulation, targeting the T9–T10 disc space following paresthesia mapping. Subjects with chronic intractable low back and leg pain (visual analogue scale [VAS] ≥ 50 mm) were enrolled. The primary endpoint was change in overall pain (VAS) at the three‐month visit compared to baseline. Subjects were followed through 12 months. Secondary endpoints included changes in low back and leg pain, quality of life (European Quality of Life – Five Dimensions, EQ‐5D‐5L), disability (Oswestry Disability Index, ODI), individual subject goals, and subject satisfaction. Results There was a significant reduction in overall pain (VAS; 45.4 mm) through the three‐month visit, which was sustained through 12 months. At 12 months, 79% of subjects had ≥50% improvement in at least one pain domain (overall, lowback or leg) with 85% of subjects reporting therapy satisfaction. There was a decrease in disability and an improvement in quality of life with 70% of subjects achieving a personal activity goal by the three‐month visit. Conclusions Long‐term pain relief and improvement in quality of life and function were achieved when following a standardized workflow. Clinical Trial Registration: The Clinicaltrials.gov registration number for the study is NCT03345472.

Introduction Despite Accredited Counsel of Graduate Medical Education (ACGME) guidance and criteria, there remains variability in training both within each specialty and across the specialties involved in the delivery of neuromodulation. NANS advocates for the efficacious and safe the implementation of neuromodulation and therefore an educational mentoring program with a defined educational platform is needed. Materials and methods This is a structured, patient centered, and evidence-based approach mentorship program performed more than one year. Mentor/Mentee pairs started in 2015 and data collected were more than a five-year period. Results There was a 70%-86% response rate on each survey administered. All except one respondent reported that the mentorship program met their previously declared expectations. All the respondents self-reported at least a moderate increase in their knowledge in the field of neuromodulation while 54% of the respondents felt their knowledge in the field to have greatly increased. Most respondents reported an increase in the number of spinal cord stimulator trials and permanent implants performed after the mentorship program. The self-reporting of mentees competencies at the conclusion of the program was statistically significant for higher competency scores in all areas assessed. Conclusions The NANs mentorship program met expectations and implementation goals by improving neuromodulation education including covering patient care, delivery, and training topics. The mentoring program provides a structured framework for extending formal physician neuromodulation education outside of direct fellowship training.

Objectives The evolution of neuromodulation devices in order to enter magnetic resonance imaging (MRI) scanners has been one of understanding limitations, engineering modifications, and the development of a consensus within the community in which the FDA could safely administer labeling for the devices. In the initial decades of neuromodulation, it has been contraindicated for MRI use with implanted devices. In this review, we take a comprehensive approach to address all the major products currently on the market in order to provide physicians with the ability to determine when an MRI can be performed for each type of device implant. Materials and methods We have prepared a narrative review of MRI guidelines for currently marketed implanted neuromodulation devices including spinal cord stimulators, intrathecal drug delivery systems, peripheral nerve stimulators, deep brain stimulators, vagal nerve stimulators, and sacral nerve stimulators. Data sources included relevant literature identified through searches of PubMed, MEDLINE/OVID, SCOPUS, and manual searches of the bibliographies of known primary and review articles, as well as manufacturer-provided information. Results Guidelines and recommendations for each device and their respective guidelines for use in and around MR environments are presented. Conclusions This is the first comprehensive guideline with regards to various devices in the market and MRI compatibility from the American Society of Pain and Neuroscience.

ObjectiveTo conduct a systematic literature review of dorsal root ganglion (DRG) stimulation for pain.DesignGrade the evidence for DRG stimulation.MethodsAn international, interdisciplinary work group conducted a literature search for DRG stimulation. Abstracts were reviewed to select studies for grading. General inclusion criteria were prospective trials (randomized controlled trials and observational studies) that were not part of a larger or previously reported group. Excluded studies were retrospective, too small, or existed only as abstracts. Studies were graded using the modified Interventional Pain Management Techniques–Quality Appraisal of Reliability and Risk of Bias Assessment, the Cochrane Collaborations Risk of Bias assessment, and the US Preventative Services Task Force level-of-evidence criteria.ResultsDRG stimulation has Level II evidence (moderate) based upon one high-quality pivotal randomized controlled trial and two lower-quality studies.ConclusionsModerate-level evidence supports DRG stimulation for treating chronic focal neuropathic pain and complex regional pain syndrome.

Background Spinal cord stimulators (SCSs) are used for treating chronic pain. The number of SCSs implanted each year is on the increase. The North American Neuromodulation Society (NANS) education committee aimed to develop a SCS curriculum as a tool to guide physicians at different training levels, based on the most recent evidence. Material and methods A multidisciplinary (anesthesiology, physical medicine, neurosurgery, and neurology), taskforce representing the education committee of the NANS met to develop a SCS curriculum following the Accreditation Council for Graduate Medical Education (ACGME) milestones. The task force used the best available evidence and knowledge to develop the curriculum. Once developed, the SCS curriculum was then approved by the NANS board. Results The task force developed a SCS training curriculum. Milestones included patient care and procedural skills, system-based practice, medical knowledge, interpersonal communication, practice based learning and professionalism. Each milestone was defined for three categories, early learner, advanced learner, and practitioner. Conclusion A multidisciplinary task force of the NANS education committee developed a SCS training curriculum that defines ACGME milestones for basic learners, advanced learners, and practitioners.

Introduction: Since the introduction of burst spinal cord stimulation for neuropathic pain, several companies have developed their own version of burst stimulation, which is confusing the marketplace and clinicians of what burst stimulation truly is, the value and utilization of the therapy.Areas covered: We review those two burst stimulation designs and notice important differences. The original burstDRTM stimulation tries to mimic physiologic burst firing, which involves closely spaced high frequency sodium spikes nested on a calcium mediated plateau. This is realized by generating a train of 5 monophasic spikes of increasing amplitude with passive charge balance after the last spike, in contrast to the other burst designs which involve a version of cycling 4-5 spikes each being individually actively charge balanced spikes.Expert opinion: Based on the neurobiology of burst firing as well as abductive reasoning we like to clarify that burstDRTM is a true physiologic burst stimulation, and that other versions being called burst stimulation are essentially clustered tonic stimulation. This differentiating terminology will prevent confusion for healthcare providers, regulators, and the marketplace of what burst stimulation is.

Summary Background Spinal cord stimulation has been an established treatment for chronic back and leg pain for more than 50 years; however, outcomes are variable and unpredictable, and objective evidence of the mechanism of action is needed. A novel spinal cord stimulation system provides the first in vivo, real-time, continuous objective measure of spinal cord activation in response to therapy via recorded evoked compound action potentials (ECAPs) in patients during daily use. These ECAPs are also used to optimise programming and deliver closed-loop spinal cord stimulation by adjusting the stimulation current to maintain activation within patients' therapeutic window. We aimed to examine pain relief and the extent of spinal cord activation with ECAP-controlled closed-loop versus fixed-output, open-loop spinal cord stimulation for the treatment of chronic back and leg pain. Methods This multicentre, double-blind, parallel-arm, randomised controlled trial was done at 13 specialist clinics, academic centres, and hospitals in the USA. Patients with chronic, intractable pain of the back and legs (Visual Analog Scale [VAS] pain score ≥60 mm; Oswestry Disability Index [ODI] score 41–80) who were refractory to conservative therapy, on stable pain medications, had no previous experience with spinal cord stimulation, and were appropriate candidates for a spinal cord stimulation trial were screened. Eligible patients were randomly assigned (1:1) to receive ECAP-controlled closed-loop spinal cord stimulation (investigational group) or fixed-output, open-loop spinal cord stimulation (control group). The randomisation sequence was computer generated with permuted blocks of size 4 and 6 and stratified by site. Patients, investigators, and site staff were masked to the treatment assignment. The primary outcome was the proportion of patients with a reduction of 50% or more in overall back and leg pain with no increase in pain medications. Non-inferiority (δ=10%) followed by superiority were tested in the intention-to-treat population at 3 months (primary analysis) and 12 months (additional prespecified analysis) after the permanent implant. This study is registered with ClinicalTrials.gov , NCT02924129 , and is ongoing. Findings Between Feb 21, 2017, and Feb 20, 2018, 134 patients were enrolled and randomly assigned (67 to each treatment group). The intention-to-treat analysis comprised 125 patients at 3 months (62 in the closed-loop group and 63 in the open-loop group) and 118 patients at 12 months (59 in the closed-loop group and 59 in the open-loop group). The primary outcome was achieved in a greater proportion of patients in the closed-loop group than in the open-loop group at 3 months (51 [82·3%] of 62 patients vs 38 [60·3%] of 63 patients; difference 21·9%, 95% CI 6·6–37·3; p=0·0052) and at 12 months (49 [83·1%] of 59 patients vs 36 [61·0%] of 59 patients; difference 22·0%, 6·3–37·7; p=0·0060). We observed no differences in safety profiles between the two groups. The most frequently reported study-related adverse events in both groups were lead migration (nine [7%] patients), implantable pulse generator pocket pain (five [4%]), and muscle spasm or cramp (three [2%]). Interpretation ECAP-controlled closed-loop stimulation provided significantly greater and more clinically meaningful pain relief up to 12 months than open-loop spinal cord stimulation. Greater spinal cord activation seen in the closed-loop group suggests a mechanistic explanation for the superior results, which aligns with the putative mechanism of action for spinal cord stimulation and warrants further investigation. Funding Saluda Medical.

Introduction Dorsal root ganglion (DRG) stimulation has been established as a therapy in the treatment of chronic pain. Ideal electrode placement is guided by proper identification of the location of the DRG. The location of the S1 DRG is not well delineated and can be variable making ideal location of the electrode placement difficult based on fluoroscopic imaging. Methods This is a retrospective analysis of postoperative programming of S1 DRG leading across two centers. There were 34 lead placements in 24 patients included in this study. Programming parameters and contacts used were evaluated based on the position of the electrode in reference to the sacral border. Results The majority of the patient programming parameters were recorded at six weeks following the implant. Most commonly, the programming used a simple continuous bipole configuration. Of the 34 leads programmed, 17 (50%) had programming on the sacral border, 14 (41%) were considered posterior, and 3 (9%) were anterior to the sacral border. Conclusion This analysis of S1 DRG programming demonstrates that ideal positioning of the majority of the contacts for the electrode should be posterior and along the sacral border on fluoroscopic imaging. These findings also suggest that the S1 DRG may be located most reproducibly at the border of the intraforaminal and intracanalicular region.

Steven M Falowski,1 Sebastian F Koga,2 Trent Northcutt,3 Laszlo Garamszegi,3 Jeremi Leasure,3 Jon E Block4 1Argires-Marotti Neurosurgical Associates of Lancaster, Lancaster, PA, USA; 2Koga Neurosurgery, Covington, LA, USA; 3Aurora Spine, Carlsbad, CA, USA; 4Independent Clinical Consultant, San Francisco, CA, USACorrespondence: Jon E BlockIndependent Clinical Consultant, 2210 Jackson Street, Ste. 401, San Francisco, CA, 94115, USATel +1 415-775-7947Email jb@drjonblock.comAbstract: With an increasingly aging population globally, a confluence has emerged between the rising prevalence of degenerative spinal disease and osteoporosis. Fusion of the anterior spinal column remains the mainstay surgical intervention for many spinal degenerative disorders. However, decreased vertebral bone mineral density (BMD), quantitatively measured by dual x-ray absorptiometry (DXA), complicates treatment with surgical interbody fusion as weak underlying bone stock increases the risk of post-operative implant-related adverse events, including cage subsidence. There is a necessity for developing cages with advanced structural designs that incorporate bioengineering and architectural principles to tailor the interbody fusion device directly to the patient’s BMD status. Specifically, lattice-designed cages that mimic the web-like structure of native cancellous bone have demonstrated excellent resistance to post-operative subsidence. This article provides an introductory profile of a spinal interbody implant designed intentionally to simulate the lattice structure of human cancellous bone, with a similar modulus of elasticity, and specialized to match a patient’s bone status across the BMD continuum. The implant incorporates an open pore design where the degree of pore compactness directly corresponds to the patient’s DXA-defined BMD status, including patients with osteoporosis.Keywords: osteoporosis, interbody fusion, bone mineral, cage, degenerative disc disease

Background: Therapeutic approaches to spinal cord stimulation (SCS) continue to evolve and improve patient outcomes in patients receiving SCS therapy secondary to failed back surgery syndrome. Objectives: The aim of this study was to evaluate pain relief and other patient outcomes of SCS using selected high-dose programming parameters. Study Design: This was a prospective cohort study. Setting: This study took place at 11 centers in North America. Methods: Forty-four SCS-naive patients underwent trialing, starting with 1,000 Hz frequency, 90 µs pulse width followed by 300 Hz frequency, 800 µs pulse width, if pain relief was inadequate. Patients with 50% or greater pain relief were eligible for permanent implantation. Patient’s pain rating, global impression of change, health-related quality of life, functional disability, satisfaction/ recommendation, stimulation perception, device programming, and adverse events were assessed at 3 months postimplant. Results: There were significant improvements from baseline in mean Numeric Rating Scale (NRS11) pain scores for overall pain (7.5 to 3.8; P < 0.01), back pain (7.2 to 3.4; P < 0.01), leg pain (7.2 to 3.1; P < 0.01), Oswestry Disability Index (ODI) score (51.5 to 32.1; P < 0.01), and European Quality of Life–Five Dimensions, version 5L score (EQ-5D-5L) (0.58 to 0.74; P < 0.01). Twentyeight of 32 patients (88%) had significant, favorable improvement in Patient Global Impression of Change (PGIC). Eighty-four percent of patients were “satisfied,” and 78.1% would “definitely” recommend SCS. Eighteen patients (56%) used 1,000 Hz frequency and 90 µs pulse width exclusively; these patients experienced mean NRS-11 overall pain score improvement of 4.7 points. Device-, therapy-, or procedure-related adverse events were experienced in 19 patients (40%, 19 of 48), and all events resolved without reoperation and were similar to those observed with traditional SCS systems. Limitations: There was no active or sham comparator group, and therefore the reported effects may not be solely attributable to therapy effects and may be related to other, nonspecific effects of SCS. Conclusions: Improvements in pain relief, PGIC, EQ-5D-5L, ODI, and patient satisfaction were all clinically relevant and statistically significant. Future studies are needed to understand how these high-dose parameters perform versus a standard comparator. Key words: Spinal cord stimulation, high-frequency electrical stimulation, failed back surgery syndrome, neurostimulation, prospective, nonrandomized study

BACKGROUND Radiofrequency rhizotomy is a percutaneous procedure for trigeminal neuralgia frequently performed with intermittent awakening, although the utility and accuracy of this procedure in continuously sedated patients have not yet been evaluated. OBJECTIVE To evaluate pain relief in patients with trigeminal neuralgia undergoing radiofrequency rhizotomy under continuous sedation. METHODS Patients from 2012 to 2017 who underwent radiofrequency rhizotomy for trigeminal neuralgia were evaluated retrospectively. Barrow Neurological Institute Pain Intensity scores were assigned to determine relapse at 1 mo, 1 yr, 3 yr, and 5 yr. Descriptive relapse rates for patients with multiple sclerosis and those undergoing repeat procedures are also reported. RESULTS A total of 90.8% of procedures reported Barrow Neurological Institute I-III score at 1 mo (P

Objectives Surgical site infections (SSIs) result in significant negative clinical and economic outcomes. The objective of this study is to estimate annual health expenditures associated with spinal cord stimulation (SCS)-related infections. Materials and methods Data from the Truven MarketScan® databases were used to identify patients with an SCS implant (2009-2014) and a continuous health plan enrollment for at least 12-months before and after implant (index date). Annual expenditures were estimated for patients with a device-related infection vs. those without infection since index date. A generalized linear model estimated annual expenditures attributable to device-related infection. Multivariable expenditure models were conducted separately for patients in initial and replacement groups, controlling for demographics, comorbidities, and clinical characteristics. Results The study included 6615 patients. Multivariable expenditure models revealed that patients with infection have higher annual expenditures than patients without infection. Estimated incremental annual healthcare expenditures for patients with an infection were $59,716 (95% CI: $48,965-$69,480) for initial implanted patients and $64,833 (95% CI: $37,377-$86,519) for replacement patients. Only 26% of patients who were explanted for infection underwent a reimplant. Conclusions These results show the substantial expenditure burden associated with an SCS-related infection. Management of SCS-related infection is important from both clinical and economic standpoints. The economic and clinical data presented here reinforce the need for additional research and strategies for healthcare providers to minimize SCS infections. Future economic research is needed to further define the specific economic cost drivers associated with the extensive expenditure burden.

Background Stimulation of the dorsal root ganglion (DRG) in the treatment of chronic, intractable pain has shown excellent clinical results in multiple published studies, including a large prospective, randomized, controlled trial. Both safety and efficacy have been demonstrated utilizing this therapeutic approach for many chronic complaints. Continued assessment of neuromodulation therapies, such as DRG stimulation, are not only an important aspect of vigilant care, but are also necessary for the evaluation for safety. Materials and methods Safety and complaint records for DRG and spinal cord stimulation (SCS) stimulation were obtained from the manufacturer, analyzed and compiled to further assess ongoing device safety. Complaint event data were stratified according to complain type as well as overall rates. Data from similar time periods were compared between epidural neurostimulation devices by the same manufacturer as well as rates reported in the literature. Results Overall, DRG stimulation device event rates were lower or comparable to similar epidurally placed neurostimulation devices. Rates of events varied from 0 to 1.0% for DRG stimulation (n >500+ implants) which was similar to the event rate for SCS by the same manufacturer (n >2000+ implants). In comparison, complaints and adverse events ranged from 0 to 14% for SCS in the literature. Discussions The current results from a large consecutive cohort obtained from manufacturer records indicates that DRG stimulation demonstrates an excellent safety profile. Reported event rates are similar to previously reported adverse event and complaint rates in the literature for this therapy. Similarly, safety events rates were lower or similar to previously reported rates for SCS, further demonstrating the comparative safety of this neuromodulation technique for chronic pain treatment.

Objective Surgical site infections can cause negative clinical and economic outcomes. A recent international survey on Spinal Cord Stimulation (SCS) infection control practices demonstrated low compliance with evidence‐based guidelines. This study defines infection rate for SCS implants and identifies infection risk factors. Materials and Methods A retrospective analysis of the MarketScan® Databases identified patients with SCS implant (2009–2014) and continuous health plan enrollment for ≥12‐months (12 m) preimplant. For logistic regression analysis, patients were enrolled for 12 m postimplant. Kaplan–Meier and Cox Proportional Hazard survival analyses assessed time to infection, with infection rate reported at 12 m postimplant. Logistic regression characterized risk factors based on demographics, comorbidities, and clinical characteristics. Results In the logistic regression (n = 6615), 12 m device‐related infection rate was 3.11%. Infection risk factors included peripheral vascular disease (OR, 1.784; 95% CI: 1.011–3.149; p = 0.0457) and infection in 12 m before implant (OR, 1.518; 95% CI: 1.022–2.254; p = 0.0386). The odds of patients experiencing an infection decreased by 3.2% with each additional year of age (OR, 0.968; 95% CI: 0.952–0.984; p < 0.0001). Survival analysis (n = 13,214) identified prior infection (HR, 1.770; 95% CI: 1.342–2.336; p < 0.0001) as a risk factor. Infection was less likely in older patients (HR, 0.974; 95% CI: 0.962–0.986; p < 0.0001). Expected risk factors including obesity, diabetes, and smoking were not identified as risk factors in this analysis. There was no significant difference between infection rate for initial and replacement implants. Conclusions The 3.11% SCS‐related infection rate within 12 m of implant emphasizes the need for improved infection control practices. Research is needed to limit SCS infections in younger patients and those with infection history.

Jason E Pope,1 Timothy R Deer,2 Steven M Falowski3 1Evolve Restorative Center, Santa Rosa, CA, USA; 2The Spine and Nerve Center of the Virginias, Charleston, WV, USA; 3Neurosurgical Associates of Lancaster, Lancaster, PA, USACorrespondence: Jason E Pope Email popeje@me.comIntroduction: Low-back pain with accompanying neurogenic claudication is a common diagnosis in pain and spine centers around the world, with an evolving algorithm of treatment. One option for the treatment of neurogenic claudication by decompressive strategies centers on percutaneous direct decompressive techniques. Although commonly employed in clinical practice, there have been no formal investigations looking at safety of percutaneous direct decompression without the use of an epidurogram and relying on osteal landmarks. The purpose of this study was to investigate the safety of percutaneous direct decompression performed without the use of the epidurogram.Methods: After an IRB exemption had been obtained from the Western Investigational Review Board, data were retrospectively analyzed from July 2018 to August 2020 on patients that had undergone percutaneous direct decompression using the Mild procedure in a single center by a single physician. Data were analyzed quantitatively for reported complications within 3 months of the procedure, including nerve injury, hematoma, infection, death, or allergic reaction to contrast use.&#x2013Results: Chart review yielded 147 individual patients who had undergone percutaneous direct decompression from July 2018 to August 2020. In this data set, women outnumbered men, with an average age of 76 years, with L4–L5 followed by L3–L4 being the most common levels decompressed. Of the 147 patients was performed, utilizing an epidurogram versus no epidurogram for decompression, with no complications. These data are the first to describe the safety of percutaneous direct lumbar decompression without the use of contrast.Conclusion: This study strongly suggests the use of an epidurogram is not necessary for the safe decompression of a patient with symptomatic spinal stenosis and neurogenic claudication utilizing percutaneous direct decompression.Keywords: spinal stenosis, lumbar stenosis, minimally invasive, epidurogram

BACKGROUND CONTEXT Psychological characteristics such as catastrophizing and depression have been shown to negatively impact outcome prognosis after spinal interventions. PURPOSE To 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/SETTINGS Data 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 SAMPLE Two subsets of study patients were identified; those with (n=31) and those without (n=54) high psychological distress. OUTCOME MEASURES Psychological 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. METHODS Psychological 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 $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 RESULTS Of 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. CONCLUSIONS Our 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.

Introduction and importance Most severe complications of DBS appear in the perioperative period. There are no published case reports of delayed ICH occurring more than three months from electrode implantation. The pathogenesis of delayed ICH remains unclear. Case presentation We present a 64-year-old male with essential tremor who sustained a delayed intracerebral hemorrhage (ICH) 2.5 years after implantation of a deep brain stimulating electrode. Discussion The patient sustained a thalamic-midbrain ICH that may have been related to the positioning of the electrode. An analysis was performed to determine the cause and risk factors that may have contributed. Based on these findings, it is possible that the proximity of the cannula or electrode may have mildly injured the wall of the superior thalamic vein during implantation, or perhaps being in contact with the vein over a longer-term having an effect, which in either of these scenarios can subsequently lead to ICH formation on the sudden rise of intracranial pressure. Conclusion It emphasizes the importance of proper surgical navigation planning, image- guidance, and the use of image verification., Highlights • No reports of delayed ICH occurring more than 3 months from DBS electrode implantation • A delayed intracerebral hemorrhage 2.5 years after implantation of a DBS electrode is reported • Possible that the cannula or electrode may have injured the wall of superior thalamic vein during implantation • DBS candidates should be instructed about delayed ICH risk

Steven M Falowski, Alexander Benison Neurosurgical Associates of Lancaster, Lancaster, PA, USACorrespondence: Steven M FalowskiDirector Functional Neurosurgery, Neurosurgical Associates of Lancaster, 160 N Pointe Blvd Suite 200, Lancaster, PA, 17601 Tel +44-358-0800Email sfalowski@gmail.comBackground: Intraoperative neuromonitoring (IONM) for spinal cord stimulation (SCS) uses electromyography (EMG) responses to determine myotomal coverage as a marker for dermatomal coverage.Objective: These responses can be utilized to evaluate the effects of stimulation platforms on the nervous system.Methods: Eight patients were tested at inter-burst frequencies of 10 Hz, 20 Hz, 30 Hz, and 40 Hz using DeRidder Burst stimulation to determine the amplitude of onset of post-synaptic signal generation. Three patients had additional data recording amplitude of onset of tonic stimulation prior to and post DeRidder Burst stimulation at each inter-burst frequency. This represented post-synaptic excitability.Results: In all patients, the DeRidder Burst waveform generated EMG responses under all inter-burst frequencies including temporal summation, deeper fiber recruitment, and compounded action potentials. There was a non-significant decrease of 7.6– 7.8% in amplitudes to generate response under 40 Hz, compared to the other frequencies. However, there was a 73.1% reduction in energy requirements at 10 Hz. The enhanced post-synaptic excitability effect was demonstrated at all frequencies.Conclusion: DeRidder Burst has similar effects of temporal summation, deeper fiber recruitment, and compounded action potentials under IONM at 40 Hz, 30 Hz, 20 Hz, and 10 Hz. In addition, the hyperexcitability phenomenon was also observed regardless of the frequency. This demonstrates that postsynaptic responses captured via IONM may be a sensitive biomarker to SCS mechanism of action. In addition, lower inter-burst frequencies may have a similar clinical effect on pain relief thus reducing power consumption even further than current dosing paradigms.Keywords: electromyogram, EMG, SCS, somatosensory evoked potentials, spinal cord stimulation, SSEPS, Burst, DeRidder Burst

Chronic pelvic pain (CPP) is a complex condition that can be multifactorial, disabling, and difficult to treat. It is important to understand the various diagnoses and pathways that can be involved and have an understanding of the available treatment options. There is a complex innervation of the pelvic region which makes its treatment very challenging. There are pathophysiological similarities of CPP to disease states like complex regional pain syndrome and sympathetically driven pain. CPP is poorly understood and includes psychological, psychosocial, cultural, and economic influences. Treatment options vary, but neuromodulation does remain a centerpiece and can include sacral stimulation, SCS, DRG stimulation, and PNS.

Peripheral nerve stimulation (PNS) is an effective tool for the treatment of chronic pain, although its efficacy and utilization have previously been significantly limited by technology. In recent years, purpose-built percutaneous PNS devices have been developed to overcome the limitations of conventional permanently implanted neurostimulation devices. Recent clinical evidence suggests clinically significant and sustained reductions in pain can persist well beyond the PNS treatment period, outcomes that have not previously been observed with conventional permanently implanted neurostimulation devices. This narrative review summarizes mechanistic processes that contribute to chronic pain, and the potential mechanisms by which selective large diameter afferent fiber activation may reverse these changes to induce a prolonged reduction in pain. The interplay of these mechanisms, supported by data in chronic pain states that have been effectively treated with percutaneous PNS, will also be discussed in support of a new theory of pain management in neuromodulation: Peripherally Induced Reconditioning of the Central Nervous System (CNS).

Jonathan M Hagedorn,1 Timothy R Deer,2 Steven M Falowski,3 Abhishek Yadav,4 Ashley Comer,2 Zayd Al-Asadi,5 Alyson M Engle2 1Department of Anesthesiology and Perioperative Medicine, Division of Pain Medicine, Mayo Clinic, Rochester, MN, USA; 2The Spine and Nerve Center of the Virginias, Charleston, WV, USA; 3Argires-Marotti Neurosurgical Associates of Lancaster, Lancaster, PA, USA; 4Department of Anesthesiology and Perioperative Medicine, Brown University, Providence, RI, USA; 5University of South Florida, Tampa, FL, USACorrespondence: Timothy R Deer Email doctdeer@aol.comIntroduction: Percutaneous neurostimulator device placement, specifically dorsal root ganglion (DRG) stimulation and spinal cord stimulation (SCS), involves the placement of thin wires within the spinal canal at specific locations, the DRG or dorsal column of the spinal cord, respectively, to provide an electrical current that modifies the pain signal as it enters the central nervous system from the periphery. Placement of neurostimulator devices is generally safe overall, but not without risk of major and minor complications. In this study, we assess the use of intraoperative neuromonitoring (IONM) as a tool to improve the safety of placing neurostimulator devices and subsequently minimizing postoperative complications.Methods: After IRB approval, an observational study was performed in 115 procedures to evaluate safety during placement of both temporary and permanent DRG and SCS systems and to document retrospectively any long-standing adverse events.Results: The rate of intraoperative neuromonitoring abnormal activity was 1.7% (n = 2), which allowed prompt recognition of nerve irritation and lead repositioning. Of the 115 consecutive implant cases performed with IONM, the postoperative minor adverse event rate was 1.7% (n = 2), which were transient and corrected with reprogramming. There were no long-standing neurological complications.Conclusion: In the largest observational study to date, we show that IONM creates a safe environment for patients undergoing SCS and DRG neurostimulator placement with the potential to decrease neurological complication rates. The use of IONM may be an alternative method to improve patient safety and outcomes as compared to monitor anesthesia care.Keywords: dorsal root ganglion, spinal cord stimulation, intraoperative neuromonitoring, safety, complications

The use of intraoperative neuromonitoring (IONM) has been adapted to address issues of safety and proper lead positioning in spinal cord stimulation. This multicenter case series seeks to incorporate the use of evoked compound action potential (ECAP) and late response (LR) recording and compare it with the results obtained with IONM, specifically electromyography (EMG), for the confirmation of lead placement. This study aimed to establish a correlation between ECAPs, LR, and EMG and publish human recordings of ECAPs and LR during their use with IONM.Standard neuromonitoring protocols were followed at two institutions, with two separate physicians and with seven patients, as part of a larger ongoing study registered with ClinicalTrials.gov (NCT02924129). Stimulation and recording were performed, top and bottom, on each percutaneous lead. Stimulation amplitude was increased considering ECAP, LR, and EMG thresholds.ECAPs, LRs, and EMG signals were observed in all patients. The onset of LR signals on implanted electrodes and EMG signal on subdermal electrodes was well correlated (rs = 0.94, p 0.001), with a median LR:EMG value of 1.06 (N = 21). LR:EMG for the top (mean = 0.97, N = 8) vs bottom (mean = 1.15, N = 13) of the lead was compared using a paired Wilcoxon signed rank test and an independent samples Mann-Whitney test, revealing a marginally significant and a statistically significant difference (p = 0.078 and p = 0.015, respectively). Mean LR:ECAP was2 in all locations and approximately 3.5 overall. LR:ECAP between the top and bottom of the lead was significantly different (Wilcoxon test, p 0.01, N = 12).LR correlated with EMG; leads with bilateral (not necessarily symmetric) EMG activity showed LR:ECAP1.5. An LR:ECAP of1, with LR/EMG generated before the ECAP, indicated that the lead is too lateral. The use of ECAP and LR has the potential of maintaining objective lead placement, without the need for needle placement with IONM.

BACKGROUND Managing cancer pain once it is refractory to conventional treatment continues to challenge caregivers committed to serving those who are suffering from a malignancy. Although neuromodulation has a role in the treatment of cancer pain for some patients, these therapies may not be suitable for all patients. Therefore, neuroablative procedures, which were once a mainstay in treating intractable cancer pain, are again on the rise. This guideline serves as a systematic review of the literature of the outcomes following neuroablative procedures. OBJECTIVE To establish clinical practice guidelines for the use of neuroablative procedures to treat patients with cancer pain. METHODS A systematic review of neuroablative procedures used to treat patients with cancer pain from 1980 to April 2019 was performed using the United States National Library of Medicine PubMed database, EMBASE, and Cochrane CENTRAL. After inclusion criteria were established, full text articles that met the inclusion criteria were reviewed by 2 members of the task force and the quality of the evidence was graded. RESULTS In total, 14 646 relevant abstracts were identified by the literature search, from which 189 met initial screening criteria. After full text review, 58 of the 189 articles were included and subdivided into 4 different clinical scenarios. These include unilateral somatic nociceptive/neuropathic body cancer pain, craniofacial cancer pain, midline subdiaphragmatic visceral cancer pain, and disseminated cancer pain. Class II and III evidence was available for these 4 clinical scenarios. Level III recommendations were developed for the use of neuroablative procedures to treat patients with cancer pain. CONCLUSION Neuroablative procedures may be an option for treating patients with refractory cancer pain. Serious adverse events were reported in some studies, but were relatively uncommon. Improved imaging, refinements in technique and the availability of new lesioning modalities may minimize the risks of neuroablation even further.The full guidelines can be accessed at https://www.cns.org/guidelines/browse-guidelines-detail/guidelines-on-neuroablative-procedures-patients-wi.

OBJECTIVES Intraoperative neuromonitoring (IONM) has been used in the implantation of spinal cord stimulation for both safety and confirmation of lead placement. It is less well defined in its use for dorsal root ganglion (DRG) stimulator placement. MATERIALS AND METHODS This is a retrospective analysis of 304 leads placed in 93 patients undergoing DRG stimulation therapy with its placement utilizing IONM in asleep patients by four implanting physicians in four separate centers. The first year, or early adoption period, of placements for each site was chosen as the included cases to evaluate. RESULTS There were a total of 14 IONM alerts across the 304 lead placements. There were two complications, no permanent or severe adverse events, and no revisions. All alerts led to a change in approach as a corrective action. The two complications were a patient requiring a blood patch for an undetected CSF leak, while the other was a generator site seroma that resolved with conservative care. A single patient experienced transient calf paresthesia's in the post-operative period. CONCLUSION This retrospective series demonstrates the utility and accuracy of IONM in not only confirming proper dorsal placement of a DRG electrode but also in maintaining a low adverse event profile. It further demonstrates that its utility in the real world with new users can be safe and accurate with an ease of integration.

Objective Burst spinal cord stimulation (B‐SCS) has been shown to reduce neuronal firing in the anterior cingulate cortex through selective modulation of the medial pain pathway tract. This pain pathway communicates the affective component of pain processing. The purpose of this study was to assess the effect of B‐SCS on psychosocial functioning and its influence on pain and quality of life. Materials and Methods Eligible patients with chronic, intractable pain of the trunk, and/or lower limbs were enrolled. After a successful trial period, subjects received a permanent implant and returned for follow‐up at 6‐ and 12‐months. Results In total, 269 patients were enrolled at 22 centers. Trial success rate was 90%. Significant improvements in pain, physical, mental, and emotional functioning were observed from baseline to the 6‐ and 12‐month follow‐up (p

Spinal cord stimulation has emerged as a state-of-the-art evidence-based treatment for chronic neuropathic pain and mixed nociceptive-neuropathic pain. In recent years, several newer devices and treatment algorithms have provided unique and effective ways of treating chronic pain by spinal cord stimulation. In a previous review, the authors commented on the 5-year forecast for high frequency and Burst waveforms, as the only two paresthesia independent SCS strategies. Over the last 5 years, there has been considerable addition to the outcome data related to these modalities. Additionally, new treatment algorithms and modalities for spinal cord stimulation have emerged. In this review, the authors provide an up to date summary of these modalities of treatment, indications, and evidence on all different modalities and programming paradigms that are available today.A literature review was performed using key bibliographic databases to find outcomes related studies pertaining to spinal cord stimulation, limited to the English language and human data, between 2010 and 2018. The literature search yielded the following based on our inclusion criteria; six articles on burst stimulation, three articled on high density/high dose stimulation, six articles on Dorsal Root Ganglion stimulation, nine articles on high-frequency stimulation, and one article on closed-loop stimulation. We have also included in the discussion some smaller and anecdotal studies.The evidence to support outcomes of spinal cord stimulation has evolved considerably since our last review in 2014. New targets, frequencies and pulse trains, and feedback appear to have advanced the efficacy of spinal cord stimulation. Future developments aim to continue to refine patient selection and maintenance of patients in therapy.

Introduction Dorsal root ganglion stimulation (DRGS) is a powerful tool in the treatment of chronic, neuropathic pain. The premise of DRGS is similar to that of conventional spinal cord stimulation (cSCS), however, there is more variability in how it can be utilized. While it is this variability that likely gives it its versatility, DRGS is not as straightforward to implement as cSCS. The purpose of this study was to assess the efficacy of DRGS on a broad number of diagnoses, determine which dorsal root ganglia were associated with better outcomes for particular body parts/diagnoses, and evaluate what factors/parameters were associated with higher rates of trial success. Methods This is a physician initiated, multicenter retrospective registry of 217 patients trialed with DRGS. Data were collected via an online questionnaire that assessed specifics regarding the patient's pain, distribution, size, and response to treatment. The data were analyzed to see if there were certain diagnoses and/or parameters that were more or less associated with trial success. Results DRGS was found to be an effective treatment in all diagnoses evaluated within this study, most of which had statistically significant improvements in pain. The most important predictor of trial success was the amount of painful area covered by paresthesias during the programing phase. The number of leads utilized had a direct and indirect impact on trial success. Pain in the distribution of a specific peripheral nerve responded best and there was no statistical difference based on what body part was being treated. Conclusion DRGS can be an effective treatment for a variety of neuropathic pain syndromes, in addition to CRPS. It is recommended that a minimum of 2 leads should be utilized per area being treated. In addition, this therapy was shown to be equally efficacious in any body part/region so long as the area being treated is focal and not widespread.

Background Peripheral neuropathy is a chronic pain disorder involving physical, chemical, or metabolic damage to peripheral nerves. Its pain can be intense and disabling. Dorsal root ganglion (DRG) stimulation is an effective treatment for neuropathic pain, including cases with the limited regional distributions that often characterize peripheral neuropathy. Methods A retrospective analysis was completed. Patients were included on the basis of having chronic intractable peripheral neuropathy of the legs and/or feet and responding successfully to a trial of DRG stimulation with leads at L4-S1. Visual analog scale pain scores and pain medication usage were collected at the baseline visit and after six weeks of treatment. Eight consecutive patients across two study centers were included (7 male, 1 female; mean age: 64.8 ± 10.2 years). Six cases of neuropathy were bilateral and two were unilateral. One patient presented with chronic radiculopathy, two patients had neuropathy associated with diabetes, and five patients had neuropathy not associated with a diabetes history. Results The pain was rated 7.38 ± 0.74 at baseline and decreased to 1.50 ± 1.31 at the 6-week follow-up, a reduction of 79.5 ± 18.8%. For individual patients, pain relief ranged from 42.86% to 100.00%; two patients experienced complete elimination of pain while seven of the eight patients experienced greater than 50% pain relief. In addition, three patients significantly decreased their pain medication use and four were able to discontinue their medications entirely. Conclusion This small multicenter retrospective case series provides preliminary evidence that the painful symptoms of general peripheral neuropathy in the lower extremities, as well as associated pain medication usage, can be effectively managed by DRG stimulation at the L4-S1 spinal level. Importantly, this treatment appears efficacious for peripheral neuropathy.

Introduction The location of the sacral dorsal root ganglion (DRG) is variable and can range from a location in the canal to the foramen. It is therefore imperative to not only ensure a dorsal placement but also map the location of the DRG. Materials and methods This is a prospective analysis of the use of intraoperative neuromonitoring (IONM) being utilized in asleep patients to map the location of the S1 DRG with somatosensory evoked potential (SSEP) and electromyogram (EMG) thresholds, as well as comparing this with postoperative programming. These observations were then correlated with the position of the electrode contacts relative to the sacral border. It was performed in a single center with 12 lead placements in eight patients. Results The IONM demonstrated that EMG thresholds decrease or stay the same as you stimulate more distal on the lead. Sensory signals are generated the majority of the time either proximal or on the sacral border. Postoperative programming correlated with the mapped location of the DRG on IONM, which was either posterior or on the sacral border. There was a single lead in which the IONM confirmed DRG location on the distal contact, which was anterior to the sacral border, and also correlated with postoperative programming. Conclusions This prospective analysis further demonstrates the utility and accuracy of IONM. The use of DRG IONM is reliable for confirming dorsal placement along the S1 DRG, mapping its position, and guiding postoperative programming. The S1 DRG is located at the border of the foramen and canal in most, but not all cases.

ObjectiveTo conduct a systematic literature review of spinal cord stimulation (SCS) for pain.DesignGrade the evidence for SCS.MethodsAn international, interdisciplinary work group conducted literature searches, reviewed abstracts, and selected studies for grading. Inclusion/exclusion criteria included randomized controlled trials (RCTs) of patients with intractable pain of greater than one year’s duration. Full studies were graded by two independent reviewers. Excluded studies were retrospective, had small numbers of subjects, or existed only as abstracts. Studies were graded using the modified Interventional Pain Management Techniques–Quality Appraisal of Reliability and Risk of Bias Assessment, the Cochrane Collaborations Risk of Bias assessment, and the US Preventative Services Task Force level-of-evidence criteria.ResultsSCS has Level 1 evidence (strong) for axial back/lumbar radiculopathy or neuralgia (five high-quality RCTs) and complex regional pain syndrome (one high-quality RCT).ConclusionsHigh-level evidence supports SCS for treating chronic pain and complex regional pain syndrome. For patients with failed back surgery syndrome, SCS was more effective than reoperation or medical management. New stimulation waveforms and frequencies may provide a greater likelihood of pain relief compared with conventional SCS for patients with axial back pain, with or without radicular pain.