The American Society of Pain and Neuroscience (ASPN) Evidence-Based Clinical Guideline of Interventional Treatments for Low Back Pain

Multifidus atrophy and/or dysfunction following lumbar radiofrequency ablation: A systematic review

BACKGROUND

Lumbar medial branch nerve radiofrequency ablation (LRFA) is an interventional procedure used to treat chronic lumbar facet joint pain. Because the medial branch nerves also innervate the multifidus muscle, it has been proposed that LRFA may pose a risk of multifidus atrophy and/or dysfunction. However, the quality and level of evidence to answer this clinical question have not been established. Therefore, this review aimed to systematically appraise the literature to discern whether the prevailing evidence substantiates the hypothesis in question.

METHODS

A systematic review compliant with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed to evaluate the quality and level of evidence of studies reporting functional and/or structural changes in the multifidus muscle following LRFA.

RESULTS

Only five cohort studies met inclusion criteria. Two studies assessed changes in multifidus function following LRFA with confirmed denervation at electromyography and significant reduction in multifidus shear modulus with ultrasound shear wave elastography. Of the four studies that evaluated changes in multifidus structure with magnetic resonance imaging following LRFA, two demonstrated a decrease in cross-sectional area or an increase in fat infiltration, one demonstrated no change, and one revealed an apparent increase. Given the destructive nature attributed to LRFA, some degree of multifidus atrophy and/or dysfunction may be plausible, albeit with a very low certainty that relies on a restricted body of literature of modest quality and with a presence of high bias.

CONCLUSION

There is a paucity of studies discussing the potential association between LRFA and multifidus atrophy and/or dysfunction. In light of the shortage of high-quality studies and the absence of standardized protocols to assess both changes in the structure and function of the multifidus subsequent to LRFA, there is a pressing need for more prospective studies with a high methodological rigor to comprehensively address and answer this enduring debate in clinical practice.

Magnetogenetic cell activation using endogenous ferritin

The ability to precisely control the activity of defined cell populations enables studies of their physiological roles and may provide therapeutic applications. While prior studies have shown that magnetic activation of ferritin-tagged ion channels allows cell-specific modulation of cellular activity, the large size of the constructs made the use of adeno-associated virus, AAV, the vector of choice for gene therapy, impractical. In addition, simple means for generating magnetic fields of sufficient strength have been lacking. Toward these ends, we first generated a novel anti-ferritin nanobody that when fused to transient receptor potential cation channel subfamily V member 1, TRPV1, enables direct binding of the channel to endogenous ferritin in mouse and human cells. This smaller construct can be delivered in a single AAV and we validated that it robustly enables magnetically induced cell activation in vitro . In parallel, we developed a simple benchtop electromagnet capable of gating the nanobody-tagged channel in vivo . Finally, we showed that delivering these new constructs by AAV to pancreatic beta cells in combination with the benchtop magnetic field delivery stimulates glucose-stimulated insulin release to improve glucose tolerance in mice in vivo . Together, the novel anti-ferritin nanobody, nanobody-TRPV1 construct and new hardware advance the utility of magnetogenetics in animals and potentially humans.

A Systematic Guideline by the ASPN Workgroup on the Evidence, Education, and Treatment Algorithm for Painful Diabetic Neuropathy: SWEET

Introduction

Painful diabetic neuropathy (PDN) is a leading cause of pain and disability globally with a lack of consensus on the appropriate treatment of those suffering from this condition. Recent advancements in both pharmacotherapy and interventional approaches have broadened the treatment options for PDN. There exists a need for a comprehensive guideline for the safe and effective treatment of patients suffering from PDN.

Objective

The SWEET Guideline was developed to provide clinicians with the most comprehensive guideline for the safe and appropriate treatment of patients suffering from PDN.

Methods

The American Society of Pain and Neuroscience (ASPN) identified an educational need for a comprehensive clinical guideline to provide evidence-based recommendations for PDN. A multidisciplinary group of international experts developed the SWEET guideline. The world literature in English was searched using Medline, EMBASE, Cochrane CENTRAL, BioMed Central, Web of Science, Google Scholar, PubMed, Current Contents Connect, Meeting Abstracts, and Scopus to identify and compile the evidence for diabetic neuropathy pain treatments (per section as listed in the manuscript) for the treatment of pain. Manuscripts from 2000-present were included in the search process.

Results

After a comprehensive review and analysis of the available evidence, the ASPN SWEET guideline was able to rate the literature and provide therapy grades for most available treatments for PDN utilizing the United States Preventive Services Task Force criteria.

Conclusion

The ASPN SWEET Guideline represents the most comprehensive review of the available treatments for PDN and their appropriate and safe utilization.

Healthcare resource utilization for chronic low back pain among high-utilizers

BACKGROUND

Chronic low back pain is a leading cause of morbidity and is among the largest cost drivers for the healthcare system. Research on healthcare resource utilization of patients with low back pain who are not surgical candidates is limited, and few studies follow individuals who generate high healthcare costs over time.

PURPOSE

This claims study aimed to identify patients with high-impact mechanical, chronic low back pain (CLBP), quantify their low back pain-related health resource utilization, and explore associated patient characteristics. We hypothesize that patients in the top quartile of healthcare resource utilization in the second year after initial diagnosis will continue to generate considerable back pain-related costs in subsequent years.

STUDY DESIGN/SETTING

IBM MarketScan Research Databases from 2009-2019 were retrospectively analyzed.

PATIENT SAMPLE

Adults in the United States with an initial diagnosis of low back pain between 2010 and 2014 who did not have cancer, spine surgery, recent pregnancy, or inflammatory spine conditions, were identified using the International Classification of Diseases (ICD) and Current Procedural Terminology (CPT) codes. To ensure patients had chronic low back pain, it was required that individuals had additional claims with a low back pain diagnosis 6 to 12 and 12 to 24 months after initial diagnosis.

OUTCOME MEASURES

Cost and utilization of inpatient visits, outpatient visits, emergency room visits, pharmacologic and nonpharmacologic treatment options and imaging for chronic low back pain.

METHODS

Annual back pain-related costs and the use of pharmacologic and nonpharmacologic treatments for 5 years were analyzed. Logistic regression was utilized to identify factors associated with persistent high spending.

RESULTS

Of 16,917 individuals who met the criteria for chronic low back pain, 4,229 met the criteria for having high healthcare utilization, defined as being in the top quartile of back pain-related costs in the 12 to 24 months after their initial diagnosis. The mean and median back pain-related cost in the first year after an initial diagnosis was $7,112 (SD $9,670) and $4,405 (Q1 $2,147, Q3 $8,461). Mean and median back pain related costs in the second year were $11,989 (SD $20,316) and $5,935 (Q1 $3,892, Q3 $10,678). Costs continued to be incurred in years 3 to 5 at a reduced rate. The cumulative mean cost for back pain over the 5 years following the initial diagnosis was $31,459 (SD $39,545). The majority of costs were from outpatient services. Almost a quarter of the high utilizers remained in the top quartile of back pain-related costs during years 3 to 5 after the initial diagnosis, and another 19% remained in the top quartile for 2 of the 3 subsequent years. For these two groups combined (42%), the 5-year cumulative mean cost for back pain was $43,818 (SD $48,270). Patient characteristics associated with a higher likelihood of remaining as high utilizers were diabetes, having a greater number of outpatient visits and pharmacologic prescriptions, and lower utilization of imaging services.

CONCLUSION

This is one of the first studies to use an administrative claims database to identify high healthcare resource utilizers among a population of United States individuals with nonsurgical, chronic low back pain and follow their utilization over time. There was a population of individuals who continued to experience high costs 5 years beyond their initial diagnosis, and the majority of individuals continued to seek outpatient services. Further longitudinal claims research that incorporates symptom severity is needed to understand the economic implications of this condition.

Variables associated with nonresponders to high-frequency (10 kHz) spinal cord stimulation

INTRODUCTION

The use of spinal cord stimulation (SCS) therapy to treat chronic pain continues to rise. Optimal patient selection remains one of the most important factors for SCS success. However, despite increased utilization and the existence of general indications, predicting which patients will benefit from neuromodulation remains one of the main challenges for this therapy. Therefore, this study aims to identify the variables that may correlate with nonresponders to high-frequency (10 kHz) SCS to distinguish the subset of patients less likely to benefit from this intervention.

MATERIALS AND METHODS

This was a retrospective single-center observational study of patients who underwent 10 kHz SCS implant. Patients were divided into nonresponders and responders groups. Demographic data and clinical outcomes were collected at baseline and statistical analysis was performed for all continuous and categorical variables between the two groups to calculate statistically significant differences.

RESULTS

The study population comprised of 237 patients, of which 67.51% were responders and 32.49% were nonresponders. There was a statistically significant difference of high levels of kinesiophobia, high self-perceived disability, greater pain intensity, and clinically relevant pain catastrophizing at baseline in the nonresponders compared to the responders. A few variables deemed potentially relevant, such as age, gender, history of spinal surgery, diabetes, alcohol use, tobacco use, psychiatric illness, and opioid utilization at baseline were not statistically significant.

CONCLUSION

Our study is the first in the neuromodulation literature to raise awareness to the association of high levels of kinesiophobia preoperatively in nonresponders to 10 kHz SCS therapy. We also found statistically significant differences with greater pain intensity, higher self-perceived disability, and clinically relevant pain catastrophizing at baseline in the nonresponders relative to responders. It may be appropriate to screen for these factors preoperatively to identify patients who are less likely to respond to SCS. If these modifiable risk factors are present, it might be prudent to consider a pre-rehabilitation program with pain neuroscience education to address these factors prior to SCS therapy, to enhance successful outcomes in neuromodulation.

Healthcare Utilization (HCU) Reduction with High-Frequency (10 kHz) Spinal Cord Stimulation (SCS) Therapy

Spinal cord stimulation (SCS) is a well-established treatment for patients with chronic pain. With increasing healthcare costs, it is important to determine the benefits of SCS in healthcare utilization (HCU). This retrospective, single-center observational study involved 160 subjects who underwent implantation of a high-frequency (10 kHz) SCS device. We focused on assessing trends in HCU by measuring opioid consumption in morphine milligram equivalents (MME), as well as monitoring emergency department (ED) and office visits for interventional pain procedures during the 12-month period preceding and following the SCS implant. Our results revealed a statistically significant reduction in HCU in all domains assessed. The mean MME was 51.05 and 26.52 pre- and post-implant, respectively. There was a 24.53 MME overall decrease and a mean of 78.2% statistically significant dose reduction (p < 0.0001). Of these, 91.5% reached a minimally clinically important difference (MCID) in opioid reduction. Similarly, we found a statistically significant (p < 0.01) decrease in ED visits, with a mean of 0.12 pre- and 0.03 post-implant, and a decrease in office visits for interventional pain procedures from a 1.39 pre- to 0.28 post-10 kHz SCS implant, representing a 1.11 statistically significant (p < 0.0001) mean reduction. Our study reports the largest cohort of real-world data published to date analyzing HCU trends with 10 kHz SCS for multiple pain etiologies. Furthermore, this is the first and only study evaluating HCU trends with 10 kHz SCS by assessing opioid use, ED visits, and outpatient visits for interventional pain procedures collectively. Preceding studies have individually investigated these outcomes, consistently yielding positive results comparable to our findings.

Posterior Lateral Arthrodesis as a Treatment Option for Lumbar Spinal Stenosis: Safety and Early Clinical Outcomes

Introduction

Lumbar spinal stenosis (LSS) is a common condition caused by degenerative changes in the lumbar spine with age. LSS is caused by a variety of factors, including degenerative spondylosis and spondylolisthesis. People suffering with LSS experience neurogenic claudication, which causes severe physical limitations, discomfort, and a decrease in quality of life. Less invasive procedures are now being researched to improve the prognosis, success rate, and safety of LSS treatments. Posterior lateral spinal arthrodesis (PLSA) is a new surgical treatment for LSS. This study looks at the procedural and patient safety of PLSA.

Materials and methods

This study is a multicenter retrospective analysis of the safety of PLSA who met the clinical indications for PLSA and underwent the procedure at eight interventional spine practices. Data was collected on demographical information, pre-procedural numeric rating scale score (NRS), post-procedural NRS, and complication reporting. Patients who were included had LSS with or without spondylolisthesis and had failed conservative treatments. A descriptive statistical analysis was performed to report the outcomes. Results were reported as mean and standard deviations for continuous outcomes, and frequency (%) for categorical outcomes.

Results

This retrospective analysis involved 191 patients and 202 PLSA implants. The majority of patients were male Caucasians with a mean age of 69.2 years and a BMI of 31.1. A large majority of implants were placed at the L4-5 level, and the average pre-procedural NRS was 6.3 while the average post-procedural NRS was 3.1, indicating a 50.8% reduction in pain (p < 0.0001). Two patients reported complications, but they were unrelated to the device or surgical procedure; no infections, device malfunctions, or migrations were reported in the patient cohort.

Conclusion

Preliminary results with PLSA implants indicate that it is a safe treatment option for patients with moderate LSS who do not respond to conservative management.

Physiatry for Treating Hip, Knee, and Back Pain

Physical Medicine and Rehabilitation (PM&R) is a rapidly expanding field. Physicians who practice PM&R are known as physiatrists and provide care primarily for patients who have disabilities or physical impairments affecting the musculoskeletal system, brain, and spinal cord. Physiatrists may work in an inpatient or outpatient setting, with outpatient physiatrists being an invaluable resource in treating patients experiencing pain. It is worthwhile to refer patients experiencing hip, knee, or back pain to a PM&R specialist because of their skill in making specific and accurate diagnoses, as well as providing a wide range of modalities to treat pain and augment function such as management of pain medications, osteopathic manipulative therapy, trigger point injections, intra-articular steroid injections, orthobiologic therapy, and interventional spinal procedures. Emphasis is on the use of the least invasive modality before employing more invasive treatments. The need for physiatrists to help individuals maximize function and enhance quality of life is increasing with the aging population, expanding workforce of older adults, and a growing population of people with a disability, especially since the COVID-19 pandemic.

Multifidus dysfunction and restorative neurostimulation: a scoping review

OBJECTIVE

Chronic low back pain (CLBP) is multifactorial in nature, with recent research highlighting the role of multifidus dysfunction in a subset of nonspecific CLBP. This review aimed to provide a foundational reference that elucidates the pathophysiological cascade of multifidus dysfunction, how it contrasts with other CLBP etiologies and the role of restorative neurostimulation.

METHODS

A scoping review of the literature.

RESULTS

In total, 194 articles were included, and findings were presented to highlight emerging principles related to multifidus dysfunction and restorative neurostimulation. Multifidus dysfunction is diagnosed by a history of mechanical, axial, nociceptive CLBP and exam demonstrating functional lumbar instability, which differs from other structural etiologies. Diagnostic images may be used to grade multifidus atrophy and assess other structural pathologies. While various treatments exist for CLBP, restorative neurostimulation distinguishes itself from traditional neurostimulation in a way that treats a different etiology, targets a different anatomical site, and has a distinctive mechanism of action.

CONCLUSIONS

Multifidus dysfunction has been proposed to result from loss of neuromuscular control, which may manifest clinically as muscle inhibition resulting in altered movement patterns. Over time, this cycle may result in potential atrophy, degeneration and CLBP. Restorative neurostimulation, a novel implantable neurostimulator system, stimulates the efferent lumbar medial branch nerve to elicit repetitive multifidus contractions. This intervention aims to interrupt the cycle of dysfunction and normalize multifidus activity incrementally, potentially restoring neuromuscular control. Restorative neurostimulation has been shown to reduce pain and disability in CLBP, improve quality of life and reduce health care expenditures.

When Does Intervention End and Surgery Begin? The Role of Interventional Pain Management in the Treatment of Spine Pathology

PURPOSE OF REVIEW

Recent advances in the field of interventional pain management (IPM) involve minimally invasive procedures such as percutaneous lumbar decompression, interspinous spacer placement, interspinous-interlaminar fusion and sacroiliac joint fusion. These developments have received pushback from surgical professional societies, who state spinal instrumentation and arthrodesis should only be performed by spine surgeons. The purpose of this review is to evaluate the validity of this claim. A literature search was conducted on Google Scholar and PubMed databases. Articles were included which examined IPM in the following contexts: credentialing and procedural privileging guidelines, fellowship training and education, and procedural outcomes compared to those of surgical specialties. Our primary research question is: "Should interventionalists be performing decompression and fusion procedures?".

FINDINGS

Advanced percutaneous spine procedures are not universally incorporated into pain fellowship curriculums. Trainees attempt to compensate for these deficiencies through industry-led training, which has been criticized for lacking central regulation. There is also a paucity of studies comparing procedural outcomes between surgeons and interventionalists for complex spine procedures, including decompression and fusion. Pain fellowship curriculums have not kept pace with some of procedural advancements within the field. Interventionalists are also not trained to manage potential complications of spinal instrumentation and arthrodesis, which has been recognized as an essential requirement for procedural privileging. Decompression and fusion may therefore be outside the scope of an interventionalist's practice.

Mechanism, application and effect evaluation of nerve mobilization in the treatment of low back pain: A narrative review

Lower back pain is a prevalent condition affecting people across all age groups and causing significant personal and societal burdens. While numerous treatments exist, nerve mobilization has emerged as a promising approach for managing lower back pain. Nerve mobilization involves applying gentle and rhythmic movements to the affected nerves, promoting normal nerve function and releasing tension. It has been well documented that nerve mobilization can be effective in reducing pain and improving function in patients with lower back pain, but the underlying mechanisms have not been clarified. This study aims to review the mechanisms of nerve mobilization in the management of lower back pain, its application, and effectiveness evaluation, and provide a potential solution for managing lower back pain.

Prolotherapy at Multifidus Muscle versus Mechanical Needling and Sterile Water Injection in Lumbar Spinal Stenosis

Objective

This observational study aimed to compare ultrasound-guided (USG) prolotherapy with 5% dextrose in water (D5W) in the multifidus muscle to USG mechanical needling and sterile water injections for the treatment of lumbar spinal stenosis (LSS).

Patients and Methods

The data was extracted from the medical records of ageing patients with LSS who received USG D5W in the multifidus muscle or USG mechanical needling and sterile water injections for the treatment of LSS by the first author. Low back pain or axial pain and leg pain or radicular pain were assessed by the visual analogue scale, and gait ability with walking distance were obtained at six different time points.

Results

Among the 211 older people who were diagnosed with LSS, 104 got USG mechanical needling and sterile water injections over the course of four weeks, while the other 107 got D5W at the multifidus muscles in a single session. Chronic low back pain, radiating pain, and the ability to walk all got much better at 1 and 3 months after the intervention, compared to VAS measures taken at the start. Patients who underwent mechanical needling with injections of sterile water performed consistently and significantly better than those who received prolotherapy in the multifidus muscles on all measures at 1, 3, and 6 months.

Conclusion

After receiving USG mechanical needling and sterile water, LSS patients reported significant improvements in low back pain, radicular pain, and ability to walk for at least 6 months. Prolotherapy with D5W in the multifidus muscle has a moderate effect for only three months.

Development and Validation of the Cognitive Behavior Questionnaire in Nonspecific Chronic Low Back Pain (CBQ-NSCLBP)

Background It's common to experience chronic low back pain (CLBP), having serious psychological as well as physical implications. The experience of CLBP and its management depends greatly on cognitive and behavioral aspects. However, there is a requirement for a valid and reliable instrument that assesses the characteristics associated with this condition. Purpose The Cognitive Behavior Questionnaire in Nonspecific Chronic Low Back Pain (CBQ-NSCLBP), a questionnaire for measuring cognitive behavior was created and validated for this study. Methodology To validate the instrument, the consensus technique with two rounds of the modified Delphi process was used. With a varied background, 13 experts in the field were specifically chosen. Utilizing the literature review, an outline of the questionnaire was created. Each of the suggested things was evaluated by the experts using a five-point Likert scale. The items completed the descriptive analysis using the criteria for validation and elimination. Results The research findings showed that the CBQ-NSCLBP had good psychometric characteristics. The content Validity Ratio (CVR) (Critical) for a panel size (N) of 13 is 0.54 & for CBQ-NSCLBP is 0.70, which was regarded as indicative of strong content validity. Test-retest reliability showed that intra-class correlation coefficient (ICC) values for all the items were greater than 0.9 which indicates excellent reliability. Spearman's correlation test between CBQ-NSCLBP and the Survey of Pain Questionnaire-Brief (SOPA-B) has shown that all the items are valid since the correlation value is higher than the cutoff value (0.139). Exploratory Factor Analysis was performed and three factors were retained based on eigenvalue greater than one. Conclusion In order to evaluate cognitive behavior in Nonspecific Chronic Low Back Pain (NSCLBP), we created this tool. This will make it easy to understand the level of cognition in NSCLBP patients.

Intra-Articular Facet Joint Injection of Normal Saline for Chronic Low Back Pain: A Systematic Review and Meta-Analysis

Objective: This systematic review and meta-analysis compared the patient-reported outcomes of intra-articular facet joint injections of normal saline and selected active substances to identify a more effective agent for treating subacute and chronic low back pain (LBP). Methods: The PubMed, Embase, Scopus, Web of Science, and CENTRAL databases were searched for randomized controlled trials and observational studies published in English. A research quality assessment was performed using ROB2 and ROBINS-I. A meta-analysis was conducted using a random-effects model, and the mean differences (MD) with 95% confidence intervals (CI) in efficacy outcomes, including pain, numbness, disability, and quality of life, were assessed. Results: Of the 2467 potential studies, 3 were included (247 patients). The active substances and normal saline had similar therapeutic effects on pain within 1 h, after 1-1.5 months, and after 3-6 months, with MD and 95% CI of 2.43 and -11.61 to 16.50, -0.63 and -7.97 to 6.72, and 1.90 and -16.03 to 19.83, respectively, as well as on the quality of life after 1 and 6 months. Conclusions: The short- and long-term clinical effects of intra-articular facet joint injections of normal saline are comparable to those of other active substances in patients with LBP.

Nonsurgical Interventional Spine Pain Procedures: Outcomes and Complications

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Nonsurgical interventional spine pain procedures provide an additional treatment option for lower back pain at the traditional bifurcation of conversative vs. operative management.

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Transforaminal epidural steroid injections, radiofrequency ablations, intrathecal drug delivery, and spinal cord stimulation were found to be effective and safe techniques when applied to their specific indication.

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Thermal annuloplasty and minimally invasive lumbar decompression showed mixed support.

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Discography, sacroiliac joint injections, and spinous process spacers lacked sufficient evidence to support efficacy.

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Medial branch blocks and facet joint injections were found to be useful diagnostic tools.