The Neurostimulation Appropriateness Consensus Committee (NACC): Recommendations on Best Practices for Cervical Neurostimulation.

INTRODUCTION: The International Neuromodulation Society convened a multispecialty group of physicians based on expertise with international representation to establish evidence-based guidance on the use of neurostimulation in the cervical region to improve outcomes. This Neurostimulation Appropriateness Consensus Committee (NACC) project intends to provide evidence-based guidance for an often-overlooked area of neurostimulation practice. MATERIALS AND METHODS: Authors were chosen based upon their clinical expertise, familiarity with the peer-reviewed literature, research productivity, and contributions to the neuromodulation literature. Section leaders supervised literature searches of MEDLINE, BioMed Central, Current Contents Connect, Embase, International Pharmaceutical Abstracts, Web of Science, Google Scholar, and PubMed from 2017 (when NACC last published guidelines) to the present. Identified studies were graded using the US Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations are based on the strength of evidence or consensus when evidence was scant. RESULTS: The NACC examined the published literature and established evidence- and consensus-based recommendations to guide best practices. Additional guidance will occur as new evidence is developed in future iterations of this process. CONCLUSIONS: The NACC recommends best practices regarding the use of cervical neuromodulation to improve safety and efficacy. The evidence- and consensus-based recommendations should be utilized as a guide to assist decision making when clinically appropriate.

Clinical Effectiveness and Mechanism of Action of Spinal Cord Stimulation for Treating Chronic Low Back and Lower Extremity Pain: a Systematic Review.

PURPOSE OF REVIEW: The purpose of the present systematic review is to provide a current understanding of the mechanism of action and the evidence available to support clinical decision-making. The focus is to summarize randomized controlled trials (RCTs) and nonrandomized or observational studies of spinal cord stimulation in chronic pain to understand clinical effectiveness and the mechanism of action. RECENT FINDINGS: Several recent studies have demonstrated the benefit of spinal cord stimulation in managing chronic pain. Until recently, the mechanism of action was founded on a central paradigm derived from gate control theory, which is the need to stimulate the dorsal column of the spinal cord to generate paresthesia. The recent development of new therapies that do not rely on paresthesia has left the field without a clear mechanism of action that could serve as a strong foundation to further improve clinical outcomes. Consequently, multiple theories have emerged to explain how electrical pulse applied to the spinal cord could alleviate pain, including activation of specific supraspinal pathways, and segmental modulation of the neurological interaction. Recent systematic reviews also have shown the clinical effectiveness of spinal cord stimulation in managing chronic spinal pain, phantom limb pain, complex regional pain syndrome, and other chronic painful conditions. Spinal cord stimulation for the treatment of chronic pain is rapidly evolving with technology at its forefront. This comprehensive focused review evaluated 11 RCTs and 7 nonrandomized/observational studies which provided levels of evidence ranging from I to II.

Effects of Phase Polarity and Charge Balance Spinal Cord Stimulation on Behavior and Gene Expression in a Rat Model of Neuropathic Pain.

OBJECTIVE: To investigate the effect of phase polarity and charge balance of spinal cord stimulation (SCS) waveforms on pain behavior and gene expression in a neuropathic pain rodent model. We hypothesized that differing waveforms will result in diverse behavioral and transcriptomics expression due to unique mechanisms of action. MATERIALS AND METHODS: Rats were implanted with a four-contact cylindrical mini-lead and randomly assigned to two control (no-pain and pain model) and five test groups featuring monophasic, as well as charge-unbalanced and charge-balanced biphasic SCS waveforms. Mechanical and cold allodynia were assessed to measure efficacy. The ipsilateral dorsal quadrant of spinal cord adjacent to the lead was harvested post-stimulation and processed to determine gene expression via real-time reverse-transcriptase polymerase chain reaction (RT-PCR). Gene expression, SCS intensity (mA), and behavioral score as percent of baseline (BSPB) were statistically analyzed and used to generate correlograms using R-Studio. Statistical analysis was performed using SPSS22.0, and p < 0.05 was considered significant. RESULTS: As expected, BSPB was significantly lower for the pain model group compared to the no-pain group. BSPB was significantly improved post-stim compared to pre-stim using cathodic, anodic, symmetric biphasic, or asymmetric biphasic 1:2 waveforms; however, BSPB was not restored to Sham levels. RT-PCR analysis showed that eight genes demonstrated a significant difference between the pain model and SCS waveforms and between waveforms. Correlograms reveal a linear correlation between regulation of expression of a given gene in relation to mA, BSPB, or other genes. CONCLUSIONS: Our results exhibit that specific SCS waveforms differentially modulate several key transcriptional pathways that are relevant in chronic pain conditions. These results have significant implications for SCS: whether to move beyond traditional paradigm of neuronal activation to focus also on modulating immune-driven processes.

Prospective, Multicenter Feasibility Study to Evaluate Differential Target Multiplexed Spinal Cord Stimulation Programming in Subjects With Chronic Intractable Back Pain With or Without Leg Pain.

OBJECTIVE: This prospective, open-label, multicenter study evaluated the feasibility of spinal cord stimulation (SCS) therapy programming for chronic low back pain that uses multiple electrical pulsed signals (Differential Target Multiplexed). METHODS: Twenty-five SCS candidates with low back pain equal to or greater than lower limb pain were enrolled at 7 sites in the United States. The subjects evaluated standard and Differential Target Multiplexed programs, each for 4 ± 1 days. A commercially available SCS trial system was used for standard SCS therapy programming. During the trialing of the multiplexed programs, implanted temporary leads were connected to an investigational external trial stimulator system. RESULTS: Twenty subjects concluded the study. The mean baseline numeric pain rating scale (NPRS) score for low back pain was 7.4, with a mean age of 62.4 years and mean pain duration of 18.0 years. Significant relief in back pain was observed for both treatments, with significantly better response with multiplexed programming. At the end of the trial period, subjects reported a reduction in their mean NPRS score from baseline to 4.2 after standard programming and to 2.4 after Differential Target Multiplexed programming. The difference between standard and multiplexed programming was significant. The responder rate for low back pain relief was 50% for standard programming and 80% for Differential Target Multiplexed programming. Eighty-five percent of subjects who evaluated both programming approaches preferred Differential Target Multiplexed SCS. CONCLUSION: In this difficult-to-treat patient population, subjects reported significant reduction in chronic back pain when using multiplexed programming. A randomized clinical trial is needed to confirm the results from this feasibility study.

Glia to neuron ratio in the posterior aspect of the human spinal cord at thoracic segments relevant to spinal cord stimulation.

Spinal cord stimulation (SCS) applied between T8 and T11 segments has been shown to be effective for the treatment of chronic pain of the lower back and limbs. However, the mechanism of the analgesic effect at these medullary levels remains unclear. Numerous studies relate glial cells with development and maintenance of chronic neuropathic pain. Glial cells are electrically excitable, which makes them a potential therapeutic target using SCS. The aim of this study is to report glia to neuron ratio in thoracic segments relevant to SCS, as well as to characterize the glia cell population at these levels. Dissections from gray and white matter of posterior spinal cord segments (T8, T9, intersection T9/T10, T10 and T11) were obtained from 11 human cadavers for histological analyses. Neuronal bodies and glial cells (microglia, astrocytes and oligodendrocytes) were immunostained, microphotographed and counted using image analysis software. Statistical analyses were carried out to establish significant differences of neuronal and glial populations among the selected segments, between the glial cells in a segment, and glial cells in white and gray matter. Results show that glia to neuron ratio in the posterior gray matter of the human spinal cord within the T8-T11 vertebral region is in the range 11 : 1 to 13 : 1, although not significantly different among vertebral segments. Glia cells are more abundant in gray matter than in white matter, whereas astrocytes and oligodendrocytes are more abundant than microglia (40 : 40 : 20). Interestingly, the population of oligodendrocytes in the T9/T10 intersection is significantly larger than in any other segment. In conclusion, glial cells are the predominant bodies in the posterior gray and white matter of the T8-T11 segments of the human spinal cord. Given the crucial role of glial cells in the development and maintenance of neuropathic pain, and their electrophysiological characteristics, anatomical determination of the ratio of different cell populations in spinal segments commonly exposed to SCS is fundamental to understand fully the biological effects observed with this therapy.

Long-term quality of life improvement for chronic intractable back and leg pain patients using spinal cord stimulation: 12-month results from the SENZA-RCT.

PURPOSE: Chronic axial low-back pain is a debilitating disorder that impacts all aspects of an afflicted individual's life. Effective, durable treatments have historically been elusive. Interventional therapies, such as spinal cord stimulation (SCS), have shown limited efficacy at best. Recently, a novel treatment, 10 kHz SCS, has demonstrated superior pain relief compared with traditional SCS in a randomized controlled trial (RCT). In this manuscript, we report on the long-term improvements in quality of life (QoL) outcomes for subjects enrolled in this study. METHODS: A prospective, multicenter, randomized controlled trial (SENZA-RCT) was conducted. Patients with both chronic back and leg pain were enrolled and randomized (1:1) into 10 kHz SCS or traditional SCS treatment groups. A total of 171 subjects received a permanent SCS device implant. QoL and functionality measures were collected up to 12 months. The device remote control utilization, which is an indication of patient interaction with the device for adjustments, was collected at 24-month post-implantation. RESULTS: At 12 months, a higher proportion of 10 kHz SCS subjects had marked improvement of their disability (Oswestry Disability Index) to a "moderate" or "minimal" impact on their daily function versus the control group. The subjects also reported better improvement in the Global Assessment of Functioning, Clinician Global Impression of Change, Pittsburgh Sleep Quality Index, and short-form McGill Pain Questionnaire, compared to traditional SCS subjects. The 10 kHz SCS subjects also reported far higher rates of both driving and sleeping with their device turned on, as well as reduced reliance on their programmers to adjust therapy settings. CONCLUSIONS: In addition to superior pain relief, 10 kHz SCS provides long-term improvements in quality of life and functionality for subjects with chronic low-back and leg pain. TRIAL REGISTRATION: ClinicalTrials.gov (NCT01609972).

Genomics of the Effect of Spinal Cord Stimulation on an Animal Model of Neuropathic Pain.

BACKGROUND: Few studies have evaluated single-gene changes modulated by spinal cord stimulation (SCS), providing a narrow understanding of molecular changes. Genomics allows for a robust analysis of holistic gene changes in response to stimulation. METHODS: Rats were randomized into six groups to determine the effect of continuous SCS in uninjured and spared-nerve injury (SNI) animals. After behavioral assessment, tissues from the dorsal quadrant of the spinal cord (SC) and dorsal root ganglion (DRG) underwent full-genome microarray analyses. Weighted Gene Correlation Network Analysis (WGCNA), and Gene Ontology (GO) analysis identified similar expression patterns, molecular functions and biological processes for significant genes. RESULTS: Microarray analyses reported 20,985 gene probes in SC and 19,104 in DRG. WGCNA sorted 7449 SC and 4275 DRG gene probes into 29 and 9 modules, respectively. WGCNA provided significant modules from paired comparisons of experimental groups. GO analyses reported significant biological processes influenced by injury, as well as the presence of an electric field. The genes Tlr2, Cxcl16, and Cd68 were used to further validate the microarray based on significant response to SCS in SNI animals. They were up-regulated in the SC while both Tlr2 and Cd68 were up-regulated in the DRG. CONCLUSIONS: The process described provides highly significant interconnected genes and pathways responsive to injury and/or electric field in the SC and DRG. Genes in the SC respond significantly to the SCS in both injured and uninjured animals, while those in the DRG significantly responded to injury, and SCS in injured animals.

Prospective, Multicenter, Randomized, Double-Blinded, Partial Crossover Study to Assess the Safety and Efficacy of the Novel Neuromodulation System in the Treatment of Patients With Chronic Pain of Peripheral Nerve Origin.

INTRODUCTION: Currently available central nervous system treatment strategies are often insufficient in management of peripheral neuropathic pain, prompting a resurgence of neuromodulation focused on peripheral pain. A new peripheral nerve stimulation device was investigated in a prospective, randomized, double blind, crossover study, looking specifically at efficacy and safety, with Food and Drug Administration oversight. METHODS: Prospective, multicenter, randomized, double-blind, partial crossover study to assess safety and efficacy. After IRB approval, patients were enrolled, implanted, and then followed for three months to assess efficacy and one year for safety based on Food and Drug Administration guidance. RESULTS: One hundred forty-seven patients were consented and screened for the study. Thirty-five did not meet inclusion or exclusion criteria. Ninety-four patients were implanted and then randomized to the treatment (45) or the Control group (49). The primary efficacy endpoint, three months after randomization to treatment, demonstrated that patients receiving active stimulation achieved a statistically significantly higher response rate of 38% vs. the 10% rate found in the Control group (p = 0.0048). Improvement in pain was statistically significant between the randomized groups, with the Treatment group achieving a mean pain reduction of 27.2% from Baseline to Month 3 compared to a 2.3% reduction in the Control group (p < 0.0001). During the partial crossover period, patients again demonstrated statistically significant improvement in pain relief with active stimulation compared to baseline. Further, the Treatment group had significantly better improvement than the Control group in secondary measures including but not limited to quality of life and satisfaction. Safety, assessed throughout the trial and with follow-up to one year, demonstrated no serious adverse events related to the device. All device-related adverse events were minor and self-limiting. CONCLUSION: The novel peripheral nerve stimulation device is a safe and effective treatment strategy to address neuropathic pain of peripheral nerve origin.

Novel 10-kHz High-frequency Therapy (HF10 Therapy) Is Superior to Traditional Low-frequency Spinal Cord Stimulation for the Treatment of Chronic Back and Leg Pain: The SENZA-RCT Randomized Controlled Trial.

BACKGROUND: Current treatments for chronic pain have limited effectiveness and commonly known side effects. Given the prevalence and burden of intractable pain, additional therapeutic approaches are desired. Spinal cord stimulation (SCS) delivered at 10 kHz (as in HF10 therapy) may provide pain relief without the paresthesias typical of traditional low-frequency SCS. The objective of this randomized, parallel-arm, noninferiority study was to compare long-term safety and efficacy of SCS therapies in patients with back and leg pain. METHODS: A total of 198 subjects with both back and leg pain were randomized in a 1:1 ratio to a treatment group across 10 comprehensive pain treatment centers. Of these, 171 passed a temporary trial and were implanted with an SCS system. Responders (the primary outcome) were defined as having 50% or greater back pain reduction with no stimulation-related neurological deficit. RESULTS: At 3 months, 84.5% of implanted HF10 therapy subjects were responders for back pain and 83.1% for leg pain, and 43.8% of traditional SCS subjects were responders for back pain and 55.5% for leg pain (P < 0.001 for both back and leg pain comparisons). The relative ratio for responders was 1.9 (95% CI, 1.4 to 2.5) for back pain and 1.5 (95% CI, 1.2 to 1.9) for leg pain. The superiority of HF10 therapy over traditional SCS for leg and back pain was sustained through 12 months (P < 0.001). HF10 therapy subjects did not experience paresthesias. CONCLUSION: HF10 therapy promises to substantially impact the management of back and leg pain with broad applicability to patients, physicians, and payers.

Analysis of efficacy differences between caudal and lumbar interlaminar epidural injections in chronic lumbar axial discogenic pain: local anesthetic alone vs. local combined with steroids.

STUDY DESIGN: Comparative assessment of randomized controlled trials of caudal and lumbar interlaminar epidural injections in chronic lumbar discogenic pain. OBJECTIVE: To assess the comparative efficacy of caudal and lumbar interlaminar approaches of epidural injections in managing axial or discogenic low back pain. SUMMARY OF BACKGROUND DATA: Epidural injections are commonly performed utilizing either a caudal or lumbar interlaminar approach to treat chronic lumbar axial or discogenic pain, which is pain exclusive of that associated with a herniated intervertebral disc, or that is due to degeneration of the zygapophyseal joints, or due to dysfunction of the sacroiliac joints, respectively. The literature on the efficacy of epidural injections in managing chronic axial lumbar pain of presumed discogenic origin is limited. METHODS: The present analysis is based on 2 randomized controlled trials of chronic axial low back pain not caused by disc herniation, radiculitis, or facet joint pain, utilizing either a caudal or lumbar interlaminar approach, with a total of 240 patients studied, and a 24-month follow-up. Patients were assigned to receive either local anesthetic only or local anesthetic with a steroid in each 60 patient group. RESULTS: The primary outcome measure was significant improvement, defined as pain relief and functional status improvement of at least 50% from baseline, which was reported at 24-month follow-ups in 72% who received local anesthetic only with a lumbar interlaminar approach and 54% who received local anesthetic only with a caudal approach. In patients receiving local anesthetic with a steroid, the response rate was 67% for those who had a lumbar interlaminar approach and 68% for those who had a caudal approach at 12 months. The response was significantly better in the lumbar interlaminar group who received local anesthetic only, 77% versus 56% at 12 months and 72% versus 54% at 24 months. CONCLUSION: This assessment shows that in patients with axial or discogenic pain in the lumbar spine after excluding facet joint and SI Joint pain, epidural injections of local anesthetic by the caudal or lumbar interlaminar approach may be effective in managing chronic low back pain with a potential superiority for a lumbar interlaminar approach over a caudal approach.

Do Epidural Injections Provide Short- and Long-term Relief for Lumbar Disc Herniation? A Systematic Review.

BACKGROUND: As part of a comprehensive nonsurgical approach, epidural injections often are used in the management of lumbar disc herniation. Recent guidelines and systematic reviews have reached different conclusions about the efficacy of epidural injections in managing lumbar disc herniation. QUESTIONS/PURPOSES: In this systematic review, we determined the efficacy (pain relief and functional improvement) of the three anatomic approaches (caudal, lumbar interlaminar, and transforaminal) for epidural injections in the treatment of disc herniation. METHODS: We performed a literature search from 1966 to June 2013 in PubMed, Cochrane library, US National Guideline Clearinghouse, previous systematic reviews, and cross-references for trials studying all types of epidural injections in managing chronic or chronic and subacute lumbar disc herniation. We wanted only randomized controlled trials (RCTs) (either placebo or active controlled) to be included in our analysis, and 66 studies found in our search fulfilled these criteria. We then assessed the methodologic quality of these 66 studies using the Cochrane review criteria for RCTs. Thirty-nine studies were excluded, leaving 23 RCTs of high and moderate methodologic quality for analysis. Evidence for the efficacy of all three approaches for epidural injection under fluoroscopy was strong for short-term (< 6 months) and moderate for long-term (≥ 6 months) based on the Cochrane rating system with five levels of evidence (best evidence synthesis), with strong evidence denoting consistent findings among multiple high-quality RCTs and moderate evidence denoting consistent findings among multiple low-quality RCTs or one high-quality RCT. The primary outcome measure was pain relief, defined as at least 50% improvement in pain or 3-point improvement in pain scores in at least 50% of the patients. The secondary outcome measure was functional improvement, defined as 50% reduction in disability or 30% reduction in the disability scores. RESULTS: Based on strong evidence for short-term efficacy from multiple high-quality trials and moderate evidence for long-term efficacy from at least one high quality trial, we found that fluoroscopic caudal, lumbar interlaminar, and transforaminal epidural injections were efficacious at managing lumbar disc herniation in terms of pain relief and functional improvement. CONCLUSIONS: The available evidence suggests that epidural injections performed under fluoroscopy by trained physicians offer improvement in pain and function in well-selected patients with lumbar disc herniation.

A continuous spinal cord stimulation model attenuates pain-related behavior in vivo following induction of a peripheral nerve injury.

OBJECTIVES: Models that simulate clinical conditions are needed to gain an understanding of the mechanism involved during spinal cord stimulation (SCS) treatment of chronic neuropathic pain. An animal model has been developed for continuous SCS in which animals that have been injured to develop neuropathic pain behavior were allowed to carry on with regular daily activities while being stimulated for 72 hours. MATERIAL AND METHODS: Sprague-Dawley rats were randomized into each of six different groups (N = 10-13). Three groups included animals in which the spared nerve injury (SNI) was induced. Animals in two of these groups were implanted with a four-contact electrode in the epidural space. Animals in one of these groups received stimulation for 72 hours continuously. Three corresponding sham groups (no SNI) were included. Mechanical and cold-thermal allodynia were evaluated using von Frey filaments and acetone drops, respectively. Mean withdrawal thresholds were compared. Statistical significance was established using one-way ANOVAs followed by Holm-Sidak post hoc analysis. RESULTS: Continuous SCS attenuates mechanical allodynia in animals with neuropathic pain behavior. Mechanical withdrawal threshold increases significantly in SNI animals after 24 and 72 hours stimulation vs. SNI no stimulation (p = 0.007 and p < 0.001, respectively). SCS for 24 and 72 hours provides significant increase in mechanical withdrawal thresholds relative to values before stimulation (p = 0.001 and p < 0.001, respectively). Stimulation did not provide recovery to baseline values. SCS did not seem to attenuate cold-thermal allodynia. CONCLUSION: A continuous SCS model has been developed. Animals with neuropathic pain behavior that were continuously stimulated showed significant increase in withdrawal thresholds proportional to stimulation time.

Epidemiology of low back pain in adults.

OBJECTIVE: Low back pain affects many individuals. It has profound effects on well-being and is often the cause of significant physical and psychological health impairments. Low back pain also affects work performance and social responsibilities, such as family life, and is increasingly a major factor in escalating health-care costs. A global review of the prevalence of low back pain in the adult general population has shown its point prevalence to be approximately 12%, with a one-month prevalence of 23%, a one-year prevalence of 38%, and a lifetime prevalence of approximately 40%. Furthermore, as the population ages over the coming decades, the number of individuals with low back pain is likely to increase substantially. This comprehensive review is undertaken to assess the increasing prevalence of low back pain and the influence of comorbid factors, along with escalating costs. MATERIALS AND METHODS: A narrative review with literature assessment. RESULTS: In the USA, low back pain and related costs are escalating. Based on the available literature, it appears that the prevalence of low back pain continues to increase, along with numerous modalities and their application in managing low back pain. Comorbid factors with psychological disorders and multiple medical problems, including obesity, smoking, lack of exercise, increasing age, and lifestyle factors, are considered as risk factors for low back pain. CONCLUSION: Although it has been alleged that low back pain resolves in approximately 80% to 90% of patients in about six weeks, irrespective of the administration or type of treatment, with only 5% to 10% of patients developing persistent back pain, this concept has been frequently questioned as the condition tends to relapse and most patients experience multiple episodes years after the initial attack.

Targeted Nerve Root Stimulation Alleviates Intractable Chronic Limb Pain Associated with Complex Regional Pain Syndrome - A Prospective Multi-Center Feasibility Study.

BACKGROUND: There are limited therapeutic options to treat complex regional pain syndrome (CRPS). Spinal cord stimulation and dorsal root ganglion stimulation are proven therapies for treating chronic low limb pain in CRPS patients. There is limited evidence that stimulation of dorsal nerve roots can also provide relief of lower limb pain in these patients. OBJECTIVES: To demonstrate that electrical stimulation of dorsal nerve roots via epidural lead placement provides relief of chronic lower limb pain in patients suffering from CRPS. STUDY DESIGN: Prospective, open label, single arm, multi-center study. SETTING: The study was performed at the Center for Interventional Pain and Spine (Exton, PA), Millennium Pain Center (Bloomington, IL), and the Carolinas Pain Center (Huntersville, NC). It was approved by the Western Institutional Review Board-Copernicus Group Institutional Review Board and is registered at clinicaltrials.gov (NCT03954080). METHODS: Sixteen patients with intractable chronic severe lower limb pain associated with CRPS were enrolled in the study. A standard trial period to evaluate a patients' response to stimulation of the dorsal nerve roots was conducted over 3 to 10-days. Patients that obtained 50% or greater pain relief during the trial period underwent permanent implantation of a neurostimulation system. The primary outcome was the evaluated pain level after 3 months of device activation, based on NRS pain score relative to baseline. Patients were followed up for 6 months after activation of the permanently implanted system. RESULTS: At the primary endpoint, patients reported a significant (P = 0.0006) reduction in pain of 3.3 points, improvement in quality of life, improved neuropathic pain characteristics, improved satisfaction, and an overall perception of improvement with the therapy. Improvements were sustained throughout the duration of the study up to the final 6-month visit. LIMITATIONS: Due to the COVID-19 pandemic occurring during patient enrollment, only 16 patients were enrolled and trialed, with 12 being permanently implanted. Nine were able to complete the end of study evaluation at 6 months. CONCLUSIONS: The results of this short feasibility study confirm the functionality, effectiveness, and safety of intraspinal stimulation of dorsal nerve roots in patients with intractable chronic lower limb pain due to CRPS using commercially approved systems and conventional parameters.

A randomized controlled study of the long-term efficacy of cooled and monopolar radiofrequency ablation for the treatment of chronic pain related to knee osteoarthritis.

Background: Chronic knee pain due to osteoarthritis (OA) is expected to become more prevalent. Although conventional therapies may provide relief they are not long-lasting. Persistent pain may lead to total knee replacement, which is not free of adverse outcomes. Monopolar and cooled radiofrequency ablation (RFA) of genicular nerves is an effective option. However, either method may provide distinctive results depending on expected lesion size, a key aspect considering the anatomical variability of knee innervations. This prospective, double-blind, randomized controlled trial evaluated the efficacy and durability of knee RFA using a cooled probe or a monopolar probe of comparable diameter. Methods: This investigator-initiated, post-market, double-blinded, prospective, randomized controlled trial was approved by the Western IRB. 79 subjects with chronic knee pain due to knee OA were enrolled in multiple locations of a single center. 75 subjects were randomized (1:1) into RFA treatment with either a 4 â€‹mm/17G cooled active tip (CRFA) or a 10 â€‹mm/16G monopolar active tip (MRFA) using conventional procedures. Primary endpoint was change in knee pain level (100 â€‹mm VAS score) from baseline at 24-week post-treatment. Other endpoints include change in functionality, global perceived effect, and frequency of adverse events. Evaluation spanned to 52-week post-treatment. Significance of results (p â€‹< â€‹0.05) was calculated using standard statistical analyses. Results: Both CRFA and MRFA provided significant reduction (41 â€‹mm and 39 â€‹mm, respectively) of chronic knee pain at 24-week. At the 52-week visit, reduction in pain level was sustained for CRFA (42 â€‹mm) but seems to decrease for MRFA (31 â€‹mm). Improvements in functionality were also significant and sustained with both treatments, although tend to decrease with MRFA at 52-week. Most patients also perceived a very good/good effect of treatments along the duration of the study. Conclusion: RFA of knee genicular nerves for the treatment of OA chronic pain is effective for 52 weeks post-ablation when using a CRFA (4 â€‹mm/17G active tip) or MRFA (10 â€‹mm/16G active tip). The benefits of CRFA seems to be better sustained beyond 24 weeks than the ones of MRFA, although no significant differences were observed at 52 weeks.

Is spinal cord stimulation an effective treatment option for discogenic pain?

INTRODUCTION: In a prospective observational study conducted in an urban pain management center, we evaluated whether spinal cord stimulation (SCS) is effective in relieving discogenic pain of IDD origin. METHODS: Thirteen patients with intractable discogenic low back pain were enrolled. Four patients never underwent permanent implantation due to insurance denial, medical reasons or failed trial and served as a control group. Nine patients underwent SCS implantation (treatment group). All patients were followed for 12 months and assessed at each interval for pain (NRS), disability (ODI), and opioid use. RESULTS: Nine patients completed the SCS trial with > 50% pain relief. The pretrial NRS score was 7.8 ± 0.5 mm in treated patients vs. 6.5 ± 1.7 mm in control patients. At 3, 6 and 12 months, the NRS was reduced to 2.9 ± 0.7 mm, 1.7 ± 0.5 mm, and 2.9 ± 0.5 mm, respectively in treated patients. NRS was unchanged in the control patients (6.5 ± 1.9 mm). The ODI score prior to the SCS trial in treated patients was 53.1 ± 3.4% vs. 54.0 ± 20.5 in control patients. At 3, 6 and 12 months the ODI scores were 39.0 ± 8.0%, 38.7 ± 4.6%, and 41.1 ± 3.9%, respectively in the treated patients, and 48.5 ± 29.5 at 12 months in control patients. In 6 patients receiving opioids prior to the SCS trial, average consumption was reduced by 69% (P = 0.036) over 12 months of therapy as compared with a 54% increase in the control patients. SCS usage was stable over the 12-month study. CONCLUSIONS: The current study indicates that SCS may provide effective pain relief, improve disability, and reduce opioid usage in patients with discogenic pain.

Long-term results of percutaneous lumbar decompression mild(®) for spinal stenosis.

BACKGROUND: Lumbar spinal stenosis (LSS) generally occurs from a combination of degenerative changes occurring in the lumbar spine. These include hypertrophy of ligamentum flavum, facet joint arthritic changes and bulging of the intervertebral disk. Spinal stenosis leads to compression of the lumbar neural elements (cauda equina), which manifests as low back and leg pain especially on standing and walking known as "neurogenic claudication." Current treatment options for LSS are varied. Conservative management, including physical therapy with/without epidural steroid injections, may be adequate for mild stenosis. Surgical decompression is reserved for severe cases and results in variable degrees of success. Patients with moderate-to-severe LSS having ligamentum flavum hypertrophy as a key contributor are generally inappropriately treated or undertreated. This is due to ineffectiveness of conservative therapy and possibility that major surgical compression might be too aggressive. Percutaneous decompression offers a possible solution for this patient population. METHODS: One-year follow-up study was conducted at 11 U.S. sites. Study cohort included 58 mild(®) percutaneous decompression patients who underwent 170 procedures, the majority treated bilaterally at one or two lumbar levels. Outcome measures included the visual analog scale (VAS), Oswestry Disability Index (ODI), Zurich Claudication Questionnaire (ZCQ), and SF-12v2(®) Health Survey. RESULTS: No major mild(®) device or procedure-related complications were reported. One-year data showed significant reduction of pain as measured by VAS. Improvement in physical functionality, mobility, and disability was significant as measured by ZCQ, SF-12v2, and ODI. CONCLUSIONS: At 1 year this 58-patient cohort demonstrated continued excellent safety profile of the mild(®) procedure and equally important, showed long-term pain relief and improved functionality.

Safety and Efficacy of Platelet Rich Plasma for Treatment of Lumbar Discogenic Pain: A Prospective, Multicenter, Randomized, Double-blind Study.

BACKGROUND: Interventions for chronic discogenic spine pain are currently insufficient in lowering individual patient suffering and global disease burden. A 2016 study of platelet rich plasma (PRP) for chronic discogenic pain previously demonstrated clinically significant response among active group patients compared with controls. OBJECTIVES: To replicate the previous research to move this intervention forward as a viable option for patient care. STUDY DESIGN: A double-blind, randomized, placebo-controlled study. SETTING: Multicenter private practices. METHODS: Twenty-six (12 men, 14 women) human patients, ages 25 to 71 with a diagnosis of chronic lumbar discogenic pain, were randomly assigned to active (PRP) or control (saline) groups in a ratio of 2 active to 1 control. Baseline and follow-up Oswestry Disability Index and Numeric Pain Rating Scale questionnaires were obtained to track patient outcomes at 8 weeks postoperatively. RESULTS: Within group assessment showed clinically significant improvement in 17% of PRP patients and clinically significant decline in 5% (1 patient) of the active group. Clinically significant improvement was seen in 13% of placebo group patients and no placebo patients had clinically significant decline secondary to the procedure. LIMITATIONS: Possible explanations may include a range of factors including differences in patient demographics, outcome-measure sensitivity, or misalignment of statistical analyses. CONCLUSIONS: These findings are markedly different than the highly promising results of the 2016 PRP study. This study posits necessary caution for researchers who wish to administer PRP for therapeutic benefit and may ultimately point to necessary redirection of interventional research for discogenic pain populations.

Percutaneous sacroplasty and sacroiliac joint cementation under fluoroscopic guidance for lower back pain related to sacral metastatic tumors with sacroiliac joint invasion.

Cancer patients with bone metastases are at risk of a variety of skeletal events, including vertebral compression and pathologic fractures. Approximately 30% to 40% of patients with advanced lung cancer will develop bone metastases in the course of their disease, resulting in a significant negative impact on both morbidity and survival. Skeletal complications of bone metastases include pain, pathologic fractures, spinal cord compression, and hypercalcemia. The spine is the most frequent site of skeletal metastases. We present a 48-year-old female with intractable and incapacitating low back pain because of metastatic bone tumor in the left lateral side of S1 and S2 with left sacroiliac invasion. Imaging identified a metastatic invasion of the sacrum. Percutaneous sacroplasty, a safe and effective procedure for sacral-insufficient fractures, was performed under fluoroscopy guidance. However, the expected pain relief was not achieved. At 1 month, the patient remained invalided by severe back pain, which was localized to the left sacroiliac joint. In a second procedure, the sacroiliac joint was cemented. Pain relief was complete, immediate, and sustained until the patient's death related to the underlying oncologic disease. No complications were observed. Few reports exist about the treatment of sacral metastatic tumors with percutaneous sacroplasty. Further, no previous reports about sacroiliac joint cementation for joint stabilization have been found. In the present case, sacroiliac joint cementation successfully resolved residual pain that remained despite percutaneous sacroplasty treatment of the pathologic sacral fracture.

Pain relief and opioid usage in upper limb and neck pain patients after 10-kHz spinal cord stimulation treatment: subanalysis of USA studies.

Aim: It is argued that chronic pain patients who reduce/eliminate their opioids may have compromised pain relief. This study therefore aimed to analyze if reduced opioid consumption associated with 10-kHz spinal cord stimulation adversely affected pain relief. Methods: Post hoc analysis was performed on data from two prospective studies in subjects with upper limbs and neck pain conducted in USA. Results & conclusion: A 10-kHz spinal cord stimulation treatment was associated with reduction in mean visual analog scale scores for upper limbs and neck pain and mean daily opioid consumption. Pain scores decreased in subjects who decreased opioid use and in those who maintained/increased use. Opioid reduction and pain relief was also achieved in subjects taking >90 mg morphine equivalents of opioids at baseline.