The Effectiveness of Spinal Cord Stimulation for the Treatment of Axial Low Back Pain: A Systematic Review with Narrative Synthesis

Spinal Cord Stimulation Waveforms for the Treatment of Chronic Pain

PURPOSE OF REVIEW

Since the advent of spinal cord stimulation (SCS), advances in technology have allowed for improvement and treatment of various conditions, especially chronic pain. Additionally, as the system has developed, the ability to provide different stimulation waveforms for patients to treat different conditions has improved. The purpose and objective of the paper is to discuss basics of waveforms and present the most up-to-date literature and research studies on the different types of waveforms that currently exist. During our literature search, we came across over sixty articles that discuss the various waveforms we intend to evaluate.

RECENT FINDINGS

There are several publications on several waveforms used in clinical practice, but to our knowledge, this is the only educational document teaching on waveforms which provides essential knowledge. There is a gap of knowledge related to understanding wave forms and how they work.

Role of patient selection and trial stimulation for spinal cord stimulation therapy for chronic non-cancer pain: a comprehensive narrative review

Background/importance

Patient selection for spinal cord stimulation (SCS) therapy is crucial and is traditionally performed with clinical selection followed by a screening trial. The factors influencing patient selection and the importance of trialing have not been systematically evaluated.

Objective

We report a narrative review conducted to synthesize evidence regarding patient selection and the role of SCS trials.

Evidence review

Medline, EMBASE and Cochrane databases were searched for reports (any design) of SCS in adult patients, from their inception until March 30, 2022. Study selection and data extraction were carried out using DistillerSR. Data were organized into tables and narrative summaries, categorized by study design. Importance of patient variables and trialing was considered by looking at their influence on the long-term therapy success.

Findings

Among 7321 citations, 201 reports consisting of 60 systematic reviews, 36 randomized controlled trials (RCTs), 41 observational studies (OSs), 51 registry-based reports, and 13 case reports on complications during trialing were included. Based on RCTs and OSs, the median trial success rate was 72% and 82%, and therapy success was 65% and 61% at 12 months, respectively. Although several psychological and non-psychological determinants have been investigated, studies do not report a consistent approach to patient selection. Among psychological factors, untreated depression was associated with poor long-term outcomes, but the effect of others was inconsistent. Most RCTs except for chronic angina involved trialing and only one RCT compared patient selection with or without trial. The median (range) trial duration was 10 (0–30) and 7 (0–56) days among RCTs and OSs, respectively.

Conclusions

Due to lack of a consistent approach to identify responders for SCS therapy, trialing complements patient selection to exclude patients who do not find the therapy helpful and/or intolerant of the SCS system. However, more rigorous and large studies are necessary to better evaluate its role.

Durable patient-reported outcomes following 60-day percutaneous peripheral nerve stimulation (PNS) of the medial branch nerves

Background

Chronic low back pain (CLBP) is often associated with clinical evidence of central nervous system sensitization and finding a clear source of nociceptive input can be challenging. Conventional therapies targeting peripheral spinal pain structures can fail to address centrally-mediated, underlying causes of pain. Sixty-day percutaneous peripheral nerve stimulation (PNS) applied to the lumbar medial branch nerves is a non-surgical, non-opioid treatment that may restore the balance of peripheral inputs to the central nervous system and reverse maladaptive changes in central pain processing. As a minimally invasive, non-destructive treatment, percutaneous PNS was designed to be used earlier in the treatment continuum than radiofrequency ablation or permanently-implanted neurostimulation systems.

Objective

The objective of this clinical trial was to characterize the durability of responses to medial branch PNS in a prospective multicenter case series study of CLBP patients recalcitrant to multiple non-surgical treatments.

Design

Prospective, multicenter clinical trial.

Population

Adults with CLBP without radicular leg pain who had previously failed multiple types of conventional treatments.

Intervention

Sixty-day percutaneous PNS applied to the lumbar medial branch nerves.

Methods

Percutaneous PNS leads were implanted under image guidance (ultrasound and/or fluoroscopy) and treatment was applied for up to 60 days, after which the leads were removed. Participants were followed through 14 months (12 months after the 2-month PNS treatment). Prospectively-defined endpoints included assessments of pain intensity, disability, pain interference, health-related quality of life, depression, and patient global impression of change.

Results

Treatment of CLBP with 60-day percutaneous PNS treatment produced clinically meaningful improvements in average pain intensity, disability, and/or pain interference for a majority of participants through the entire 14 month follow up period without requiring permanent system implantation. The proportion of participants experiencing clinically meaningful improvement in at least one outcome (pain intensiy, disability, pain interference) with PNS was 91% after 2 months, 79% at 5 months, 73% at 8 months, 75% at 11 months, and 77% at 14 months. There were no serious or unanticipated study-related adverse events.

Conclusion

This prospective multicenter clinical trial demonstrates the clinical utility of percutaneous PNS when applied to the medial branch nerves for the treatment of chronic low back pain recalcitrant to non-surgical treatments. Given the minimally invasive nature of percutaneous PNS and the significant benefits experienced by participants, percutaneous PNS provides a safe and effective first-line neuromodulation treatment for patients with CLBP that may obviate the need for neuroablative procedures or permanent neurostimulation system implantation.

Spinal cord stimulation for treatment of chronic neuropathic pain in adolescent patients: a single-institution series, systematic review, and individual participant data meta-analysis

OBJECTIVE

Neuropathic pain is undertreated in children. Neurosurgical treatments of pediatric chronic pain are limited by the absence of both US Food and Drug Administration approval and pediatric-specific hardware, as well as weak referral patterns due to a lack of physician education. This study presents a single-institution retrospective case series of spinal cord stimulation (SCS) in children ≤ 19 years of age and a systematic review of SCS in children. The authors’ findings may further validate the role of SCS as an effective treatment modality for varied neuropathic pain syndromes found in pediatric patients.

METHODS

The study was a single-center, single-surgeon, retrospective case series of individuals treated between July 2017 and May 2022. The outcomes for pediatric patients with chronic neuropathic pain syndromes indicated by the multidisciplinary pain clinic for evaluation for SCS were cataloged. A systematic review and individual participant data (IPD) meta-analysis was performed for cases treated until May 2022, using PubMed, EMBASE, and Scopus to characterize outcomes of children with neuropathic pain treated with SCS.

RESULTS

Twelve patients were evaluated and 9 were indicated for percutaneous or buried lead trials. Seven female and 2 male patients between the ages of 13 and 19 years were implanted with trial leads. Eight of 9 (89%) patients went on to receive permanent systems. The average trial length was 6 days, and the length of stay for both trial and implant was less than 1 day. Complication rates due to CSF leaks were 22% and 0% for trial and implant, respectively. Visual analog scale pain scores decreased from 9.2 to 2.9 (p = 0.0002) and the number of medications decreased from 4.9 to 2.1 (p = 0.0005). Functional status also improved for each patient. A systematic review identified 13 studies describing pediatric patients with SCS, including 12 providing IPD on 30 patients. In the IPD meta-analysis, pain was reduced in 16/16 (100%) of patients following surgery and in 25/26 (96.2%) at last follow-up. Medication use was decreased in 16/21 (76.2%), and functional outcomes were improved in 29/29 (100%). The complication rate was 5/30 (16.7%).

CONCLUSIONS

SCS effectively decreases pain and medication use for pediatric neuropathic pain syndromes. Patients also report improved functional status, including improved matriculation, gainful employment, and physical activity. There is minimal high-quality literature describing neuromodulation for pain in children. Neuromodulation should be considered earlier as a viable alternative to escalating use of multiple drugs and as a potential mechanism to address tolerance, dependence, and addiction in pediatric patients.

Evidence-Based Clinical Guidelines from the American Society of Pain and Neuroscience for the Use of Implantable Peripheral Nerve Stimulation in the Treatment of Chronic Pain

The objective of this peripheral nerve stimulation consensus guideline is to add to the current family of consensus practice guidelines and incorporate a systematic review process. The published literature was searched from relevant electronic databases, including PubMed, Scopus, Cochrane Central Register of Controlled Trials, and Web of Science from database inception to March 29, 2021. Inclusion criteria encompassed studies that described peripheral nerve stimulation in patients in terms of clinical outcomes for various pain conditions, physiological mechanism of action, surgical technique, technique of placement, and adverse events. Twenty randomized controlled trials and 33 prospective observational studies were included in the systematic review process. There is Level I evidence supporting the efficacy of PNS for treatment of chronic migraine headaches via occipital nerve stimulation; chronic hemiplegic shoulder pain via stimulation of nerves innervating the trapezius, supraspinatus, and deltoid muscles; failed back surgery syndrome via subcutaneous peripheral field stimulation; and lower extremity neuropathic and lower extremity post-amputation pain. Evidence from current Level I studies combined with newer technologies facilitating less invasive and easier electrode placement make peripheral nerve stimulation an attractive alternative for managing patients with complex pain disorders. Peripheral nerve stimulation should be used judiciously as an adjunct for chronic and acute postoperative pain following adequate patient screening and positive diagnostic nerve block or stimulation trial.

Do racial and ethnic disparities lead to the undertreatment of pain? Are there solutions?

PURPOSE OF REVIEW

The current review aims to empower anesthesiologists, specifically pain medicine specialists, to become leaders in ensuring equitable care.

RECENT FINDINGS

Disparities in both acute and chronic pain medicine lead to increased morbidity for patients of color. Gaps in care include misdiagnosis or under diagnosis of chronic pain disease states, undertreatment of sickle cell disease and other conditions that are common in minorities, under prescription of opioids, and lack of access to novel opioid sparing treatments. While the causes of these disparities are multifactorial, care team implicit bias and lack of representation are two of the major factors. Solutions are challenging, but the authors suggest an inside out solution. We believe that this practice will have far-reaching downstream effects, including improving diversity in our field and quality of care for our patients.

SUMMARY

The current article reviews disparities in both acute and chronic pain treatment for underrepresented racial and ethnic minorities in the United States. The authors examine whether implicit bias and lack of representation are a contributing factor for these disparities. Lastly, we will discuss potential solutions.

Spinal Cord Stimulation as an Alternative to Opioid for Axial Neck and Back Pain: A Case Series

Introduction

Spinal cord stimulation is emerging as a minimally invasive technique for treatment of persistent spinal pain syndrome (PSPS).

Methods

We describe a case series of 25 individuals with PSPS who underwent implantation of a spinal cord stimulator device between 2017 and 2021.

Results

There was a significant reduction in mean visual analog scale pain scores in the immediate postoperative phase, (8.61 vs. 2.3, p < 0.001). There were twelve patients who consumed pre-operative opioid, and 75% showed reduction of use with a significantly lower average daily dose (66.8 vs. 26.9 meq/D, p < 0.05). There was a significant reduction in the Oswestry Disability Index during postoperative follow-up visits (p < 0.001). There were no major perioperative or long-term complications from the procedure in follow-up.

Conclusion

The analysis of this cohort suggests successful long-term treatment of a diverse set of patients with PSPS who underwent spinal cord stimulation (SCS) and had meaningful improvement in quality of life and reduction in opioid consumption.

Pain Relief and Safety Outcomes with Cervical 10 kHz Spinal Cord Stimulation: Systematic Literature Review and Meta-analysis

BACKGROUND

Chronic pain in head, neck, shoulders and upper limbs is debilitating, and patients usually rely on pain medications or surgery to manage their symptoms. However, given the current opioid epidemic, non-pharmacological interventions that reduce pain, such as spinal cord stimulation (SCS), are needed. The purpose of this study was to review the evidence on paresthesia-free 10 kHz SCS therapy for neck and upper extremity pain.

METHODS

Systematic literature search was performed for studies reporting outcomes for cervical 10 kHz SCS using date limits from May 2008 to November 2020. The study results were analyzed and described qualitatively. Additionally, when feasible, meta-analyses of the outcome data, with 95% confidence intervals (CIs), were conducted using both the fixed-effects (FE) and random-effects (RE) models.

RESULTS

A total of 15 studies were eligible for inclusion. The proportion of patients who achieved ≥ 50% pain reduction was 83% (95% CI 77-89%) in both the FE and RE models. The proportion of patients who reduced/eliminated their opioid consumption was 39% (95% CI 31-46%) in the FE model and 39% (95% CI 31-48%) in the RE model. Pain or discomfort with the implant, lead migration, and infections were potential risks following cervical SCS. Explant rate was 0.1 (95% CI 0.0-0.2) events per 100 person-months, and no patients in the included studies experienced a neurological complication or paresthesia.

CONCLUSION

Findings suggest 10 kHz SCS is a promising, safe, minimally invasive alternative for managing chronic upper limb and neck pain.

Current Perspectives on Neurostimulation for the Management of Chronic Low Back Pain: A Narrative Review

Neurostimulation techniques for the treatment of chronic low back pain (LBP) have been rapidly evolving; however, questions remain as to which modalities provide the most efficacious and durable treatment for intractable axial symptoms. Modalities of spinal cord stimulation, such as traditional low-frequency paresthesia based, high-density or high dose (HD), burst, 10-kHz high-frequency therapy, closed-loop, and differential target multiplexed, have been limitedly studied to determine their efficacy for the treatment of axial LBP. In addition, stimulation methods that target regions other than the spinal cord, such as medial branch nerve stimulation of the multifidus muscles and the dorsal root ganglion may also be viable treatment options. Here, current scientific evidence behind neurostimulation techniques have been reviewed with a focus on the management of chronic axial LBP.