Spinal Cord Stimulators: an Introduction

Pain can be divided into two broad categories, nociceptive pain and neuropathic pain. Nociceptive pain is a dull, throbbing pain which results from irritated nerves after physical tissue injury. This is seen commonly in cancer or after a fracture. Nociceptive pain is amenable to treatment with pain medications such as opioids and/or anti-inflammatories. Neuropathic pain is described as burning, shooting, or shocking pain. This type of pain results from nerve damage or abnormal nerve conduction such as pain exhibited with failed back syndrome, post surgical pain, neuromas, shingles, and complex regional pain syndrome (previously called RSD or causalgia). Neuropathic pain tends to be resistant to treatment with pain medications. Neurostimulation has been an effective treatment option for the management of chronic neuropathic pain. It is a reversible therapy which can even be tested before permanent implantation. Spinal cord stimulation (SCS) is an adjustable, non-destructive, neuromodulatory procedure which delivers therapeutic doses of electrical current to the spinal cord or to a targeted nerve. This low-voltage stimulation can block the transmission of pain. The enthusiasm for SCS began with the introduction of the gate control theory for pain control by Melzack and Wall in 1965 1.They noted that stimulation of large myelinated fibers of peripheral nerves resulted in paresthesias and blocked the activity in small nociceptive projections. In other words, pain receptors compete with each other and with other sensory afferents. Appropriate stimulation of a “rival” afferent can effectively block a pain signal. This is why rubbing your chin after its been hit relieves the pain – the bump is still present, but the rubbing blocks it. The SCS system is implanted in a space surrounding the spinal cord, called the epidural space, where it stimulates the dorsal columns which can mask the sensation of pain by producing a tingling sensation

Occipital nerve stimulator systems: Review of complications and surgical techniques

Introduction: Stimulation of the occipital nerves is becoming more widely accepted in the treatment of occipital neuritis and migraine disorders. Objective: Presently, equipment available for spinal cord stimulation is adapted for insertion into the subcutaneous space over the occipital nerves. Many technical factors need to be reassessed to optimize the therapy. Methods: We performed a retrospective review of patients implanted from 2003 to 2007 at a single center. We aimed to analyze the rate of surgical complications related to implantation technique. A total of 28 patients were present for analysis. Patients were followed up to 60 months with a mean follow-up of 21 months. Results: There is a 32% revision rate for electrode migration or displacement, 3.6% removal rate for infection, and a 21% removal rate for lack of efficacy. Although not well studied secondary to small patient populations, this was consistent with a review of the literature which demonstrated a 10-60% revision rate. Other factors such as anchoring strategy, strain relief, and battery location were all considered in the analysis and will be presented. A major determination was that use of a second incision with an additional strain relief loop had only a 10% revision rate of the lead while those without this additional strain relief loop had a 62.5% revision rate. Conclusion: Many technical factors need to be addressed for optimization of occipital nerve stimulation

Case Report: Intramedullary Cervical Spinal Cord Hemangioblastoma with an Evaluation of von Hippel-Lindau Disease

History of Present Illness MO is a 49 year old male with a history of multiple sclerosis who presents with a one year history of progressive numbness in his shoulders bilateral and upper back. The patient describes occasional sharp pains that radiate to his first three fingers on his right hand. He denies weakness, clumsiness, difficulty walking, or bladder/bowel dysfunction. He describes no problems with handwriting, or fine motor skills

An evaluation of neuroplasticity and behavior after deep brain stimulation of the nucleus accumbens in an animal model of depression.

BACKGROUND: Recent interest has demonstrated the nucleus accumbens (NAcc) as a potential target for the treatment of depression with deep brain stimulation (DBS). OBJECTIVE: To demonstrate that DBS of the NAcc is an effective treatment modality for depression and that chemical and structural changes associated with these behavioral changes are markers of neuroplasticity. METHODS: A deep brain stimulator was placed in the NAcc of male Wistar-Kyoto rats. Groups were divided into sham (no stimulation), intermittent (3 h/d for 2 weeks), or continuous (constant stimulation for 2 weeks). Exploratory and anxietylike behaviors were evaluated with the open-field test before and after stimulation. Tissue samples of the prefrontal cortex (PFC) were processed with Western blot analysis of markers of noradrenergic activity that included the noradrenergic synthesizing enzyme tyrosine hydroxylase. Analysis of tissue levels for catecholamines was achieved with high-performance liquid chromatography. Morphological properties of cortical pyramidal neurons were assessed with Golgi-Cox staining. RESULTS: Subjects undergoing intermittent and continuous stimulation of the NAcc exhibited an increase in exploratory behavior and reduced anxietylike behaviors. Tyrosine hydroxylase expression levels were decreased in the PFC after intermittent and continuous DBS, and dopamine and norepinephrine levels were decreased after continuous stimulation. Golgi-Cox staining indicated that DBS increased the length of apical and basilar dendrites in pyramidal neurons of the PFC. CONCLUSION: Deep brain stimulation induces behavioral improvement in and neurochemical and morphological alterations of the PFC that demonstrate changes within the circuitry of the brain different from the target area of stimulation. This observed dendritic plasticity may underlie the therapeutic efficacy of this treatment

Spinal Shock: Differentiation from Neurogenic Shock and Key Management Approaches

The conceptual differentiation of spinal and neurogenic shock tends to be misunderstood among clinicians. In order to better illustrate the differences in definition, presentation, and development of spinal shock (SS) from neurogenic and other forms of shock, we present herein a clinically relevant summary of typical characteristics of SS. First described in the eighteenth century, the continued investigation into the disease process and the response of neural structures to spinal cord trauma have led to a more complete description and understanding. We will begin in the first part of the chapter describing the etiology of SS, including a working definition, as it pertains to complete spinal cord injuries (SCIs). This is followed by the summary of pathophysiology and clinical presentations associated with each clinical phase of SS. Finally, we explore treatment options and considerations as they relate to incomplete SCI. We hope that by presenting a clear and well-delineated overview of SS, we will allow the clinician to better understand and more accurately predict the evolution of this process. This, in turn, should facilitate the ability to deliver better care for the patient

Pacific Spine and Pain Society (PSPS) Evidence Review of Surgical Treatments for Lumbar Degenerative Spinal Disease: A Narrative Review.

INTRODUCTION: Interventional treatment options for the lumbar degenerative spine have undergone a significant amount of innovation over the last decade. As new technologies emerge, along with the surgical specialty expansion, there is no manuscript that utilizes a review of surgical treatments with evidence rankings from multiple specialties, namely, the interventional pain and spine communities. Through the Pacific Spine and Pain Society (PSPS), the purpose of this manuscript is to provide a balanced evidence review of available surgical treatments. METHODS: The PSPS Research Committee created a working group that performed a comprehensive literature search on available surgical technologies for the treatment of the degenerative spine, utilizing the ranking assessment based on USPSTF (United States Preventative Services Taskforce) and NASS (North American Spine Society) criteria. RESULTS: The surgical treatments were separated based on disease process, including treatments for degenerative disc disease, spondylolisthesis, and spinal stenosis. CONCLUSIONS: There is emerging and significant evidence to support multiple approaches to treat the symptomatic lumbar degenerative spine. As new technologies become available, training, education, credentialing, and peer review are essential for optimizing patient safety and successful outcomes

Core patient-reported outcome measures for chronic pain patients treated with spinal cord stimulation or dorsal root ganglia stimulation

Background: Neurostimulation is a highly effective therapy for the treatment of chronic Intractable pain, however, due to the complexity of pain, measuring a subject’s long-term response to the therapy remains difficult. Frequent measurement of patient-reported outcomes (PROs) to reflect multiple aspects of subjects’ pain is a crucial step in determining therapy outcomes. However, collecting full-length PROs is burdensome for both patients and clinicians. The objective of this work is to identify the reduced set of questions from multiple validated PROs that can accurately characterize chronic pain patients’ responses to neurostimulation therapies. Methods: Validated PROs were used to capture pain, physical function and disability, as well as psychometric, satisfaction, and global health metrics. PROs were collected from 509 patients implanted with Spinal Cord Stimulation (SCS) or Dorsal Root Ganglia (DRG) neurostimulators enrolled in the prospective, international, post-market REALITY study (NCT03876054, Registration Date: March 15, 2019). A combination of linear regression, Pearson’s correlation, and factor analysis were used to eliminate highly correlated questions and find the minimal meaningful set of questions within the predefined domains of each scale. Results: The shortened versions of the questionnaires presented almost identical accuracy for classifying the therapy outcomes as compared to the validated full-length versions. In addition, principal component analysis was performed on all the PROs and showed a robust clustering of pain intensity, psychological factors, physical function, and sleep across multiple PROs. A selected set of questions captured from multiple PROs can provide adequate information for measuring neurostimulation therapy outcomes. Conclusions: PROs are important subjective measures to evaluate the physiological and psychological aspects of pain. However, these measures are cumbersome to collect. These shorter and more targeted PROs could result in better patient engagement, and enhanced and more frequent data collection processes for digital health platforms that minimize patient burden while increasing therapeutic benefits for chronic pain patients.</p

Drug-Free Noninvasive Thermal Nerve Block: Validation of Sham Devices

Headache is a leading cause of disability and suffering. One major challenge in developing device treatments is demonstrating their efficacy given devices\u27 often-high placebo rate. This paper reviews the importance of validating sham devices as part of finalizing the design for larger-scale prospective randomized controlled trials in patients with chronic headache as well as the results of a prospective, single-blind trial to validate two potential sham noninvasive thermal nerve block devices. Study participants were trained to self-administer thermal nerve block treatment using sham devices in an office visit. Two different sham systems with different temperature profiles were assessed. Devices were offered for patients to use daily at-home for one week to assess the durability of sham placebo effects before participants were given active treatment in a second office visit followed by another optional week of self-administered active treatment at-home use. Sham treatments reduced pain scores by an average of 31% from 6.0 ± 2.3 to 4.3 ± 3.3, including two participants who fell asleep during the in-office treatment and woke up with no pain, but whose pain recurred after returning home during at-home use of the sham system. In-office active treatments reduced pain scores by 52% from 6.7 ± 2.1 to 3.3 ± 2.9 with sustained pain relief during optional at-home use. Successful blinding for the study was confirmed with an ideal Bang\u27s Blinding Index of 0 and an ideal James\u27 Blinding Index of 1. Both the sham and active treatments were viewed by participants as highly credible, and credibility increased from the beginning to end of sham treatments on average

An Evidence-Based Consensus for the Use of Neurostimulation for the Treatment of Non-Surgical Low Back Pain: The NEURON Group

IntroductionThe use of electrical neuromodulation has often been limited to those with previous back surgery, peripheral neuropathy, and complex regional pain syndrome. Many patients with severe intractable low back pain were thought to be candidates for spinal cord stimulation (SCS), dorsal root ganglion stimulation, or peripheral nerve stimulation but did not meet the criteria. Recently, additional high-level data has supported the use of SCS in non-surgical low back pain (NSLBP), and United States Food and Drug Administration approval has been granted. The American Society of Pain and Neuroscience (ASPN) executive committee realized an unmet need to develop criteria for patient selection for this specific patient population. This is a NEURON project (neuroscience, education, utilization, risk mitigation, optimal outcomes, and neuromodulation), a living guideline for evolving therapies and indications, and is focused on the use of neuraxial stimulation for the treatment of refractory pain.MethodsAfter board approval, the society accepted nominees for the project, with an emphasis on experience, publication, research, and diversity. The team created an outline for discussion, chose a grading system based on published guidelines, and created consensus points.ResultsThe evidence led to several consensus points to best guide patient selection based on the level of evidence and expert opinion. The results will lead to improved safety and efficacy in implanted patients, and to a new standard for best practices.ConclusionThe selection of patients for implantation in those who have NSLBP should be based on published literature, best practice, and expert opinion. This NEURON project will allow for regular updates to create a living guideline that will allow for better assimilation of information to improve safety and efficacy going forward

Device Evaluation, Treatment, and Explantation Recommendations (DETER): Review and Best Practices for Managing Neuromodulation Device Infections

Infections related to neuromodulation devices such as spinal cord stimulators (SCS) and intrathecal pumps (ITPs) present complex challenges due to potential complications such as localized infections, deep infections, sepsis, and neurological injury. Prompt diagnosis requires patients and providers to be educated on wound management and sepsis symptoms for immediate medical attention. Antibiotic therapy and duration vary based on infection severity, with deep infections often requiring device removal despite recent improvements in salvage rates with aggressive initial intervention. Deep infections necessitate timely diagnosis through imaging modalities such as magnetic resonance imaging (MRI) or computed tomography (CT), followed by device removal and culture-guided antibiotic therapy, often in collaboration with infectious disease specialists and spine surgeons. ITP infections pose similar challenges along with the risk of meningitis and may require careful management of medication withdrawal symptoms during emergent pump removal. Lab monitoring may aid treatment assessment, although negative cultures can occur due to post-antibiotic exposure. Postoperative recommendations stress standardized guidelines, patient education, and vigilant surveillance, with close follow-up crucial for early infection detection and intervention. Managing device-related infections demands a multi-specialty approach to minimize complications and optimize outcomes. This paper outlines best practices for diagnosing, managing, and treating neuromodulation device infections, focusing on guiding clinical decision-making from the onset of infection through treatment and potential reimplantation