Peripheral Nerve Stimulation for Low Back Pain: A Systematic Review

Methodological and statistical characteristics of meta-analyses on spinal cord stimulation for chronic pain: a systematic review

BACKGROUND

A growing number of meta-analyses (MA) have investigated the use of spinal cord stimulation (SCS) as a treatment modality for chronic pain. The quality of these MAs has not been assessed by validated appraisal tools.

OBJECTIVE

To examine the methodological characteristics and quality of MAs related to the use of SCS for chronic pain syndromes.

EVIDENCE REVIEW

An online literature search was conducted in Ovid MEDLINE(R), Ovid EMBASE, Ovid Cochrane Database of Systematic Reviews, and Scopus databases (January 1, 2000 through June 30, 2023) to identify MAs that investigated changes in pain intensity, opioid consumption, and/or physical function after SCS for the treatment of chronic pain. MA quality was assessed using A Measurement Tool to Assess Systematic Reviews (AMSTAR-2) critical appraisal tool.

FINDINGS

Twenty-five MAs were appraised in the final analysis. Three were considered "high" quality, three "low" quality, and 19 "critically low" quality, per the AMSTAR-2 criteria. There was no association between the publication year and AMSTAR-2 overall quality (β 0.043; 95% CI -0.008 to 0.095; p=0.097). There was an association between the impact factor and AMSTAR-2 overall quality (β 0.108; 95% CI 0.044 to 0.172; p=0.002), such that studies published in journals with higher impact factors were associated with higher overall quality. There was no association between the effect size and AMSTAR-2 overall quality (β -0.168; 95% CI -0.518 to 0.183; p=0.320).According to our power analysis, three studies were adequately powered (>80%) to reject the null hypothesis, while the remaining studies were underpowered (<80%).

CONCLUSIONS

The study demonstrates a critically low AMSTAR-2 quality for most MAs published on the use of SCS for treating chronic pain. Future MAs should improve study quality by implementing the AMSTAR-2 checklist items.

PROSPERO REGISTRATION NUMBER

CRD42023431155.

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

Introduction

The 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.

Methods

After 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.

Results

The 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.

Conclusion

The 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.

Peripheral Nerve Stimulation Implantation Combining Ultrasound With Microendoscopy for Management of Chronic Neuropathic Pain: A Case Series Study

BACKGROUND

Peripheral nerve stimulation (PNS) has emerged as a minimally invasive percutaneous procedure addressing neuropathic pain. However, the percutaneous cylindrical lead ultrasound-guided implantation procedure requires expertise that limits widespread PNS utilization. To overcome these challenges, a microinvasive endoscopy device has very recently been developed, enhancing the precision of PNS implantation by providing accurate visualization of the targeted nerve. We aimed to determine the feasibility, safety, clinical effectiveness, and energy consumption of PNS therapy by means of ultrasound guidance combined with microendoscopy.

MATERIALS AND METHODS

This is a retrospective, single-center, single-arm study. Patient recruitment was performed in February and March 2023. Patients with >12 months of upper or lower limb pain presenting with pain >5 of 10 that was refractory to conventional treatments were eligible. Safety was assessed by collecting adverse events and complications related to the PNS implantation with microendoscopy. The Multidimensional Clinical Response Index (MCRI), pain intensity (visual analog scale [VAS]), pain surface (PRISMap Software, PRISMATICS lab, CHU de Poitiers, Poitiers, France), quality of life (EuroQoL 5 dimensions 5 levels [EQ5D-5L]), functional disability (Oswestry Disability Index [ODI]), anxiety and depression (Hospital Anxiety and Depression Scale), and energy consumption were assessed at baseline and at one and three months.

RESULTS

Six patients received PNS, which was implanted through ultrasound guidance combined with microendoscopy. No adverse event was reported during the three-month follow-up. Clinical outcomes (MCRI, VAS, ODI, EQ5D-5L) significantly increased at one- and three-month follow-up. Energy consumption was, on average, 2.6 ± 1.1 μC.s-1 at one-month and 3.3 ± 2.0 μC.s-1 at three-month follow-up.

CONCLUSIONS

Implanted PNS by means of ultrasound combined with microendoscopy was safe and provided clinical benefits with very low energy consumption (15-440 times less than spinal cord stimulation) in patients with upper or lower limb neuropathic pain. Microendoscopy would offer extended PNS indications, overcoming limitations associated with ultrasound alone. Future research is nonetheless needed to provide stronger evidence through randomized controlled trial design.

Peripheral Nerve Stimulation for Pain Management: A Survey of Clinical Practice Patterns

BACKGROUND

Clinical interest in and utilization of peripheral nerve stimulation (PNS) for treating chronic pain has significantly increased in recent years owing to its potential for providing analgesia and improved function and quality of life in comparison with pharmacologic treatments. However, the relative infancy of PNS-specific systems and limited clinical practice guidance likely contribute to significant variation in PNS utilization patterns.

OBJECTIVES

We sought to conduct a survey study to characterize PNS-specific clinical practices and propose the next steps in standardizing key practices for PNS utilization.

MATERIALS AND METHODS

A 19-question survey exploring PNS-relevant clinical parameters was disseminated online to pain physicians in practice. Descriptive statistics were used to summarize results.

RESULTS

A total of 94 responses were collected. Regarding patient selection, most practitioners would apply PNS to treat nociceptive pain from major joint osteoarthritis (77.7%) and chronic low back pain (64.9%), but not for axial neck pain (50.0%). In contrast, most would apply PNS to treat neuropathic pain from peripheral neuralgia (94.7%), pericranial neuralgia (77.7%), and cancer-related neuropathic pain (64.9%). In treating complex regional pain syndrome, most practitioners would apply PNS before all other forms of neuraxial neuromodulation (>50% for each form). Similarly, for treating nonsurgical low back pain, most would apply PNS before neuraxial neuromodulation (>50% for each form) but not before radiofrequency ablation (19.2%). Most routinely performed nerve blocks before PNS, mainly to confirm anatomical coverage (84.0%), and regarded a 50% to 75% interquartile range as the minimum analgesic benefit required before proceeding with PNS. Regarding nerve target selection for treating complex regional pain syndrome of the wrist/hand or ankle/foot, or knee osteoarthritis, we observed a very wide variance of PNS target locations and discrete nerves. Regarding "minor" adverse events, most reported not changing PNS utilization on encountering skin/soft tissue reactions (85.1%), minor infections (76.6%), or lead migration/loss of efficacy (50.0%). In comparison, most reported reducing PNS utilization on encountering skin erosion (58.5%), major infections (58.5%), or lead fractures (41.5%).

CONCLUSIONS

There is significant practice variation regarding the utilization of PNS across numerous key clinical considerations. Future research that explores the reasons driving these differences might help optimize patient selection, target selection, periprocedural management, and ultimately outcomes.

Spatial Distribution Dynamics of Sensory Disturbances in the Treatment of Obesity-Related Meralgia Paresthetica Using Transcutaneous Electrical Nerve Stimulation

Background: To date, there have been no studies on the dynamics of areas of pain, paraesthesia and hypoesthesia after the use of various transcutaneous electrical nerve stimulation in the treatment of meralgia paresthetica. Methods: In this pilot study, we observed 68 patients with obesity-related bilateral meralgia paresthetica. Pain syndrome, paraesthesia symptoms, and hypoesthesia were evaluated using 10-point scores. In addition, pain drawing (PD) was used to determine the area of the spatial distribution of pain syndrome and paraesthesia symptoms, and body drawing was used to determine the area of hypoesthesia. Sham TENS was performed in the control group, and effective TENS was performed in the treatment group. The treatment group consisted of two subgroups. One subgroup underwent HF-LA TENS, and the second subgroup underwent LF-HA TENS. Results: Despite the greatest analgesic effect observed from HF-LA TENS, which was assessed using scoring methods, during and after treatment, the reduction in the area of pain and paraesthesia symptoms and the area of hypoesthesia was moderate, short-term, and reversible. In contrast, LF-HA TENS had a pronounced analgesic and sustained anti-paraesthesia effect, manifested by a noticeable decrease in pain and paraesthesia symptoms area in PD, gradually increasing during the first 2 months of follow-up and accompanied by an irreversible prolonged decrease in the area of hypoesthesia. Conclusion: The areas of paraesthesia and hypoesthesia correlate with affective reactions to long-term chronic pain, which noticeably regress under the influence of LF-HA TENS compared to HF-LA TENS.

Clinical outcomes for minimally invasive sacroiliac joint fusion with allograft using a posterior approach

BACKGROUND

Sacroiliac joint (SIJ) dysfunction can occur as a result of injury, degeneration, or inflammation. This dysfunction presents symptoms of pain at various locations, including the low back, hips, buttocks, and legs. The diagnosis of SIJ dysfunction is challenging and cannot be achieved solely with imaging studies such as X-rays, MRI, or CT. The current gold standard diagnostic modality is intra-articular SIJ blocks using two differing local anesthetics. Current treatments for SIJ dysfunction may be beneficial for short-term relief but lack long-term efficacy. The purpose of our study was to examine the outcomes of patients who underwent minimally invasive, posterior SIJ fusion using allograft at a single center.

METHODS

This was a retrospective study which received exemption from the WCG IRB. Data regarding preoperative and postoperative pain levels, surgical time, complications, and medication usage were obtained retrospectively from patient electronic medical records and prescription drug monitoring program reports. No mapping was completed prior to the procedure. Pain was assessed with the 11-point (0-10) Visual Analogue Scale (VAS) and medication usage was assessed using Morphine Milligram Equivalents (MME). Patients were included if they had been diagnosed with SIJ dysfunction using two intra-articular diagnostic blocks that resulted in at least an 80% decrease in pain and had failed conservative management. Patients with sacral insufficiency fractures were excluded.

RESULTS

VAS scores reduced from 8.26 (SD = 1.09) at baseline to 2.59 (SD = 2.57), 2.55 (SD = 2.56), 2.71 (SD = 2.88), and 2.71 (SD = 2.88) at 3, 6, 9, and 12 months, respectively. MME reduced from 78.21 mg (SD = 51.33) to 58.95 mg (SD = 48.64), 57.61 mg (SD = 47.92), 61.71 mg (SD = 45.64), and 66.29 mg (SD = 51.65) at 3, 6, 9, and 12 months, respectively. All reductions in VAS scores and MME were statistically significant. No adverse events occurred, and the average operating room time was 40.16 min (SD = 6.27).

CONCLUSION

Minimally invasive, posterior SIJ fusion using allograft is a safe and efficacious method for managing SIJ dysfunction.

A Review of Remote Monitoring in Neuromodulation for Chronic Pain Management

PURPOSE OF REVIEW

Neuromodulation techniques have emerged as promising strategies for managing chronic pain. These techniques encompass various modalities of nerve stimulation, including Spinal Cord Stimulation (SCS), Dorsal Root Ganglion Stimulation (DRG-S), and Peripheral Nerve Stimulation (PNS). Studies consistently demonstrate significant improvements in pain intensity, quality of life, and reduced opioid usage among patients treated with these modalities. However, neuromodulation presents challenges, such as the need for frequent in-person follow-up visits to ensure proper functionality of the implanted device. Our review explored factors impacting compliance in current neuromodulation users and examined how remote monitoring can mitigate some of these challenges. We also discuss outcomes of recent studies related to remote monitoring of neuromodulation.

RECENT FINDINGS

While remote monitoring capabilities for neuromodulation devices is an emerging development, there are promising results supporting its role in improving outcomes for chronic pain patients. Higher patient satisfaction, improved pain control, and reduced caretaker burdens have been observed with the use of remote monitoring. This review discusses the current challenges with neuromodulation therapy and highlights the role of remote monitoring. As the field continues to evolve, understanding the importance of remote monitoring for neuromodulation is crucial for optimizing pain management outcomes.

Efficacy of Back Bracing in Treating Chronic Low Back Pain

Chronic low back pain (CLBP) negatively impacts quality of life and contributes to a significant economic burden. One conservative management strategy for CLBP is lumbar back bracing. Despite the benefits of back bracing for improving pain and function, there remains hesitance to use the therapy long term due to unfounded fear related to muscle weakness, deconditioning, or joint contracture.

OBJECTIVE

The purpose of this study was to examine the outcomes for patients with CLBP who were managed with lumbar back bracing and physical therapy.

METHODS

This was a single-site, retrospective chart review.

RESULTS

Patients were included in the study if they were treated for CLBP with back bracing for at least one hour daily and physical therapy for twelve weeks. Pain was assessed at three, six, and twelve months using the 11-point Visual Analogue Scale (VAS). Function was assessed at three months using the Oswestry Disability Index (ODI). The VAS score reduced from 6.28 +/- 2.32 to 3.96 +/- 2.66 at three months (p < 0.001) for 198 patients. At six and twelve months, the VAS score reduced to 3.74 +/- 2.73 (p < 0.001) and 3.23 +/- 2.29 (p < 0.001), respectively. The total ODI score for 199 patients improved from 46.56 +/- 15.30 to 33.13 +/- 19.99 (p < 0.001) at three months.

CONCLUSION

Back bracing in combination with physical therapy is effective for treating low back pain.

Pain intensity and opioid consumption after temporary and permanent peripheral nerve stimulation: a 2-year multicenter analysis

OBJECTIVE

Peripheral nerve stimulation (PNS) is an emerging neuromodulation modality, yet there remains limited data highlighting its long-term effectiveness. The objective of this study was to report real-world data on pain intensity and opioid consumption after temporary and permanent PNS for chronic pain up to 24 months postimplantation.

METHODS

A retrospective study was conducted on all patients who received PNS implants at a multi-centered enterprise between January 1, 2014 and February 24, 2022. The two co-primary outcomes were: (1) change in pain intensity (11-point Numerical Rating Scale) from baseline to 12 months postimplant; and (2) comparison of the change in pain intensity between temporary and permanent PNS cohorts 12 months postimplant.

RESULTS

126 patients were included in this analysis. Pain intensity significantly decreased 12 months postimplant in the overall cohort (mean difference (MD) -3.0 (95% CI -3.5 to -2.4), p<0.0001). No significant difference in this reduction was identified between temporary and permanent PNS cohorts (MD 0.0 (95% CI -1.1 to 1.0), p=1.00) 12 months postimplantation. Pain intensity significantly decreased in the overall, temporary, and permanent cohorts at all secondary time points (3, 6, and 24 months). No change in daily opioid consumption was observed at 6 and 12 months postimplant in the overall cohort.

CONCLUSION

This study found that both temporary and permanent PNS may be effective for reducing pain intensity in patients with chronic pain up to 24 months postimplantation, although no changes in opioid consumption were observed. The decrease in pain intensity was comparable between patients receiving temporary versus permanent implants, highlighting that temporary PNS may achieve long-lasting clinical benefits. However, given the substantial loss to follow-up, further large-scale studies are needed to solidify conclusions about the efficacy of PNS.

Is Response to a Pre-implant Diagnostic Peripheral Nerve Block Associated With Efficacy After Peripheral Nerve Stimulation Implantation? A Ten-Year Enterprise-Wide Analysis

OBJECTIVES

This study aimed to assess whether patient response to targeted diagnostic peripheral nerve block before peripheral nerve stimulator (PNS) device implantation is associated with efficacy after PNS implantation.

MATERIALS AND METHODS

The electronic medical records from the Mayo Clinic Enterprise (three quarternary care medical centers and additional satellite medical centers) were reviewed to identify patients who underwent PNS implantation between January 2014 and January 2023. A primary outcome of interest was to assess whether administration of a preimplant diagnostic peripheral nerve block predicted pain relief at three months and six months after temporary and permanent PNS implantation. Another primary outcome was to investigate whether there was an association between the pain relief from a preimplant diagnostic peripheral nerve block and pain relief after three and six months after temporary or permanent PNS therapy. Linear regression analysis was conducted for outcomes of interest.

RESULTS

Of 193 eligible patients who underwent PNS therapy, a total of 173 patients were included in the final analysis and were stratified into either the temporary PNS cohort (n = 112) or the permanent PNS cohort (n = 61). Overall, 77.5% of all patients (134/173) underwent a preimplant diagnostic peripheral nerve block and reported a mean percentage relief of 70.1 ± 27.0 from the diagnostic block. Of patients in the temporary PNS cohort, there was no difference in postimplant percentage pain relief between patients who received a diagnostic block (n = 93) and control patients (n = 19) at three months (35.4 ± 36.0 vs 49.8 ± 36.1, respectively; β -14.45, 95% CI -32.98 to 4.07, p = 0.125) or at six months (23.3 ± 30.8 vs 45.7 ± 40.0, respectively; β -22.39, 95% CI -46.86 to 2.08, p = 0.072). Of patients in the permanent PNS cohort, there was no difference in postimplant percentage pain relief between patients who received a diagnostic block (n = 41) and control patients (n = 20) at three months (42.4 ± 34.3 vs 43.2 ± 42.4, respectively; β -0.79, 95% CI -23.56 to 21.99, p = 0.945) or at six months (44.3 ± 35.0 vs 38.8 ± 40.9, respectively; β 5.42, 95% CI -20.04 to 30.88, p = 0.669). Pain relief from preimplant diagnostic blocks was associated with postimplant pain relief from temporary PNS at three months (β 0.33, 95% CI 0.04-0.61, p = 0.025). However, pain relief from preimplant diagnostic blocks did not predict postimplant pain relief from temporary PNS at six months, or permanent PNS at three months and six months.

CONCLUSIONS

Administration of a diagnostic block is not associated with superior pain relief at three or six months after PNS implantation to that of an approach without diagnostic block. Pain relief from a diagnostic block may potentially predict short-term pain relief after temporary PNS therapy, although future prospective studies are warranted to evaluate the prognostic utility of diagnostic blocks.

A review of prospective studies regarding percutaneous peripheral nerve stimulation treatment in the management of chronic pain

Conventionally, peripheral nerve stimulation (PNS) for treatment of chronic pain has involved a two-stage process: a short-term (e.g., 7 days) trial and, if significant pain relief is achieved, a permanent PNS system is implanted. A percutaneous PNS treatment is now available where a coiled lead may be implanted for up to 60 days with the goal of producing sustained relief. In the present review, published prospective trials using percutaneous PNS treatment were identified and synthesized. The collected evidence indicates that percutaneous PNS treatment for up to 60 days provides durable clinically significant improvements in pain and pain interference. Similar efficacy across diverse targets and etiologies supports the broad applicability for use within the chronic pain population using this nonopioid technology.

Peripheral Nerve Stimulation for Pain Management: A Review

PURPOSE OF REVIEW

Peripheral nerve stimulation has seen a recent upsurge in utilization for various chronic pain conditions, specifically from a neuropathic etiology, where a single peripheral nerve can be pinpointed as a culprit for pain.

RECENT FINDINGS

There is conflicting evidence about the efficacy and long-term outcomes of peripheral nerve stimulation for chronic pain, with most studies being small sized. The focus of this article is to review available evidence for the utilization of peripheral nerve stimulation for chronic pain syndromes as well as upcoming evidence in the immediate postoperative realm. The indications for the use of PNS have expanded from neuropathic pain such as occipital neuralgia and post-amputation pain, to more widespread disease processes such as chronic low back pain. Percutaneous PNS delivered over a 60-day period may provide significant carry-over effects including pain relief, potentially avoiding the need for a permanently implanted system while enabling improved function in patients with chronic pain.