Lumbar radiculopathy and its neurobiological basis

A nerve root decompression position identified by 3D CT scan: the modified reversed contralateral axial rotation position for patients with lumbar disc prolapse

BACKGROUND

Nerve root compression in the lumbar intervertebral foramen (LIVF) is a consistent feature of radicular syndrome. There is debate about movements and positions that may reduce compression for possible use in conservative treatment.

PURPOSE

To investigate real-time effects of specific 3 dimensional positioning of the trunk on the cross sectional area (CSA) of the LIVF in patients with lumbar disc prolapse and radiculopathy using 3D-CT scan imaging.

METHODS

Ninety males aged between 20 and 40 years with unilateral lumbar disc prolapse and radiculopathy were separated into three equal groups based on the level of disc prolapse. Group (A): L3/L4, group (B): L4/L5, and group (C): L5/S1. All underwent three separate imaging sessions; first in the supine position to establish baseline data (Baseline-Image 1), followed by a modified reversed contralateral axial rotation position (Image 2), and finally the same position as Image 2 but after 48 h of using the position as a therapeutic intervention (Image 3). The CSA of LIVF at L3/L4, L4/L5, and L5/S1 levels and the angles of straight leg raising (SLR) test were measured following each imaging session.

RESULTS

Two-way mixed MANOVA analysis revealed that the mean values of the CSA of LIVF and the angle of SLR test were significantly increased in Image 2 compared with Baseline-Image 1 across all tested groups (P = 0.001). Moreover, the measured outcome variables were significantly increased in Image 3 compared with Image 2 and Baseline-Image 1 across all tested groups (P = 0.001).

CONCLUSION

The modified reversed contralateral axial rotation position of the trunk had a real-time decompression effect on the impinged nerve roots in patients with unilateral lumbar disc prolapse and radiculopathy.

Serum brain-derived neurotrophic factor level in patients with disc induced lumbosacral radiculopathy: Relation to pain severity and functional disability

BACKGROUND

Pain is the major cause of disability in disc induced lumbosacral radiculopathy (LSR) and is related to neurotrophins mainly brain derived neurotrophic factor (BDNF). However, to our knowledge evaluating serum BDNF in disc induced LSR has not been reported before. This study was done to investigate serum BDNF in LSR patients and its relation to pain severity and functional disability.

METHODS

This case-control study included 40 disc induced LSR patients and 40 age and sex matched healthy subjects. All patients were subjected to neurological examination, electrophysiological evaluation, pain severity assessment using numerical rating scale (NRS) and functional disability assessment using Modified Oswestry Low Back Pain Disability Index (ODI) and Maine-Seattle Back Questionnaire (MSBQ). According to Douleur neuropathique 4 (DN4) questionnaire, patients were divided into those with neuropathic pain and those with non-neuropathic pain. Serum BDNF was measured by enzyme-linked immunosorbent assay in all participants.

RESULTS

Serum BDNF was significantly higher in LSR patients than in healthy controls (U=272.5, P<0.001). Moreover, serum BDNF was significantly higher in those with neuropathic pain compared to those with non-neuropathic pain (U=35, P=0.03). Serum BDNF had a significant positive correlation with NRS score among those with acute pain (rs=0.537, P=0.026), however there was no significant correlation among those with chronic pain. Furthermore, BDNF had no significant correlation with modified ODI and MSBQ.

CONCLUSION

Increased serum BDNF may be associated with neuropathic pain and acute pain severity in disc induced LSR. However, it may not be related to chronic pain severity or functional disability.

Efficacy of Percutaneous Laser Disc Decompression (PLDD) Combined with an Oral Food Supplement for Lumbar Disc Herniation

Background: In recent years, minimally invasive treatment options for lumbar disc herniation, such as percutaneous laser disc decompression (PLDD), have been introduced to avoid more invasive surgical methods. Combining these minimally invasive approaches with nutraceuticals that are effective in neuroprotection and pain management may lead to better long-term outcomes. Methods: The present study evaluated the beneficial effects of a new oral food supplement composed of acetyl-L-carnitine, α-lipoic acid, quercetin, bromelain, pantothenic acid, and vitamins C, B1, B2, B6, and B12 in patients with neuropathic pain due to herniated lumbar discs treated with PLDD. Patients were divided into two groups of 26 patients each: group A underwent PLDD alone, while group B underwent PLDD followed by a dietary supplement for two months after surgery. Preoperative VAS scores for leg pain were recorded for both groups and no significant difference was observed (8.7 for Group A and 8.6 for Group B). Results: In Group A, the mean postoperative VAS score for leg pain at a 1-month follow-up was 2.5, which remained stable at 3 months. In Group B, the mean postoperative VAS score was 2.0 at 1-month and improved to 1.6 at the 3-month follow-up. According to self-reported leg pain assessments, 66.5% of the patients using the dietary supplement reported a significantly better pain condition, and 43.5% reported a somewhat better situation. In contrast, 7.7% of the patients who underwent PLDD alone reported no changes in leg pain at the final follow-up. Conclusions: The results of our study indicate that the oral food supplement could provide a safe and effective treatment in patients with painful radiculopathy, enhancing the recovery of sensory fiber function in lumbar nerve roots after surgical lumbar disc decompression.

Functional Stimulation and Imaging to Predict Neuromodulation of Chronic Low Back Pain

Back pain is one of the most common aversive sensations in human experience. Pain is not limited to the sensory transduction of tissue damage; rather, it encompasses a range of nervous system activities including lateral modulation, long-distance transmission, encoding, and decoding. Although spine surgery may address peripheral pain generators directly, aberrant signals along canonical aversive pathways and maladaptive influence of affective and cognitive states can result in persistent subjective pain refractory to classical surgical intervention. The clinical identification of who will benefit from surgery-and who will not-is increasingly grounded in neurophysiology.

N-Acetyl Cysteine as an Add-on Therapy is Useful in Treating Acute Lumbar Radiculopathy Caused by Disc Herniation: Results of a Randomized, Controlled Clinical Trial

BACKGROUND

Available experimental and clinical evidence indicates that N-Acetyl cysteine (NAC) may have an analgesic role in specific pain conditions, particularly neuropathic pain. Thus, we hypothesized that NAC supplementation might be also helpful in decreasing pain and improving pain-related disability in patients with acute radiculopathy. We designed this study to investigate the potential use of NAC-adjunctive treatment to Nonsteroidal Anti- Inflammatory Drugs (NSAIDs) in patients with acute radiculopathy secondary to lumbar intervertebral disc herniation.

METHODS

Sixty-two patients diagnosed with acute lumbar radiculopathy associated with disc herniation were randomly allocated to the NAC or the placebo groups. Besides naproxen at a dose of 500 mg twice a day, participants based on their allocation group started with NAC or matched placebo at a dose of 600 mg twice a day for eight weeks. The pain severity, measured by the Visual Analog Scale (VAS), and pain-related disability measured by the Oswestry Disability Index (ODI) were measured at baseline and weeks 2, 4, and 8 of treatment. Global improvement of symptoms rated by Patient and Clinical Global Impressions of Change (PGIC and CGIC) was also recorded at the end of week 8. All analyses were conducted on an Intentionto- Treat (ITT) analysis data set.

RESULTS

A comparison of the VAS and ODI scores at weeks 2 and 4 of the treatment between the two groups did not show a significant difference. In contrast, from week 4 to week 8, we noticed a significantly greater reduction in the mean VAS and ODI scores in the NAC group compared to the placebo group (p-value <0.001 for both variables). In parallel with these results, also, more NAC-treated than placebo-treated patients achieved treatment success defined as ''very much'' or ''much improved'' on CGIC and PGIC scales, and these differences reached a significant level (p-value = .011 and p-value = .043).

CONCLUSIONS

This study suggested that NAC might be a relevant candidate for adjunct therapy in managing acute lumbar radiculopathy. Additional clinical trials are needed to validate these findings.

A comparative study of a nerve block therapy with and without a deeply inserted acupotomy applied to hyeopcheok points for lumbosacral radiculopathy: Safety, effectiveness, cost-effectiveness (a randomized controlled, two-arm, parallel study, pilot study, assessor-blind)

INTRODUCTION

The prevalence of lumbosacral radiculopathy is estimated to be approximately 3% to 5% in patient populations. Lumbosacral radiculopathy is largely caused by a complex interaction between biomechanical and biochemical factors. Nerve block therapy (NBT) mainly treats lumbosacral radiculopathy by improving the biochemical factors, whereas acupotomy mainly focuses on improving the biomechanical factors. Therefore, it is thought that synergistic effects may be obtained for the treatment of lumbosacral radiculopathy when both NBT and acupotomy are combined. However, no study in China and Korea, where acupotomy is majorly provided, has reported the effects of such a combination treatment. Therefore, this study aimed to evaluate the safety, effectiveness, and cost-effectiveness of the concurrent use of a deeply inserted acupotomy and NBT for the treatment of lumbosacral radiculopathy.

METHODS/DESIGN

This is an open-label, parallel, assessor-blinded, randomized controlled trial, which will include 50 patients with lumbosacral radiculopathy. After patients voluntarily agree to participate in the study, they will be screened, and will undergo necessary examinations and tests according to the protocol. Those who satisfy the selection criteria will be randomly assigned to either the NBT + acupotomy or NBT groups in a 1:1 ratio. Both groups will undergo 2 NBTs once every 2 weeks from 1 week after the screening test. The treatment group will receive additional acupotomy twice a week for 4 weeks. The primary endpoint is the Oswestry Disability Index, whereas the secondary endpoints are the Numeral Rating Scale, European Quality of Life 5-dimension, McGill pain Questionnaire, Roland-Morris Disability Questionnaire, safety assessment, and economic feasibility evaluation. The measurements will be made at 0, 2, 4, and 8 weeks.

ETHICS AND DISSEMINATION

This trial has received complete ethical approval from the Ethics Committee of Catholic Kwandong University International St. Mary's Hospital (IS20OISE0085). We intend to submit the results of the trial to a peer-reviewed journal and/or conferences.

Effectiveness of Low-Level Laser Therapy in Patients with Discogenic Lumbar Radiculopathy: A Double-Blind Randomized Controlled Trial

Purpose

To determine the effectiveness of low-level laser therapy (LLLT) in patients with discogenic lumbar radiculopathy and correlation among pain intensity, functional disability, and lumbar range of motion (LROM). Study Design/Setting. A double-blind RCT was conducted at physical therapy departments of different hospitals of Islamabad, Pakistan. The study period was March 2020 to August 2021. Patient Sample. The study comprised 110 patients with acute LBP and unilateral discogenic lumbar radiculopathy. Outcome Measures. The outcomes of the treatment were measured on the first day and then after 18 sessions from each patient's pain intensity, functional disability, L-ROM, and straight leg raise by using visual analogue scale, Oswestry disability index, dual inclinometer, and straight leg raise test.

Methods

A total of 110 participants with a mean age of 38 ± 7.4 years were randomly assigned into two groups of 55 each. The experimental group of 55 patients was treated with LLLT and conventional physical therapy. The control group of 55 patients was treated with conventional physical therapy alone. Both groups had received 18 treatment sessions. The data were analyzed through SPSS-21.0.

Results

The results of the Wilcoxon signed-rank test score as well as Mann–Whitney U test indicated a statistically significant difference in values (p < 0.05 in all instances) within the groups and between the groups, respectively.

Conclusions

The LLLT is proved as an efficient adjunct therapy to conventional physical therapy for discogenic lumbar radiculopathy.

ATF3-Expressing Large-Diameter Sensory Afferents at Acute Stage as Bio-Signatures of Persistent Pain Associated with Lumbar Radiculopathy

The mechanism of pain chronicity is largely unknown in lumbar radiculopathy (LR). The anatomical location of nerve injury is one of the important factors associated with pain chronicity of LR. Accumulating evidence has shown constriction distal to the dorsal root ganglion (DRG) caused more severe radiculopathy than constriction proximal to the DRG; thereby, the mechanism of pain chronicity in LR could be revealed by comparing the differences in pathological changes of DRGs between nerve constriction distal and proximal to the DRG. Here, we used 2 rat models of LR with nerve constriction distal or proximal to the DRG to probe how the different nerve injury sites could differentially affect pain chronicity and the pathological changes of DRG neuron subpopulations. As expected, rats with nerve constriction distal to the DRG showed more persistent pain behaviors than those with nerve constriction proximal to the DRG in 50% paw withdraw threshold, weight-bearing test, and acetone test. One day after the operation, distal and proximal nerve constriction showed differential pathological changes of DRG. The ratios of activating transcription factor3 (ATF3)-positive DRG neurons were significantly higher in rats with nerve constriction distal to DRG than those with nerve constriction proximal to DRG. In subpopulation analysis, the ratios of ATF3-immunoreactivity (IR) in neurofilament heavy chain (NFH)-positive DRG neurons significantly increased in distal nerve constriction compared to proximal nerve constriction; although, both distal and proximal nerve constriction presented increased ratios of ATF3-IR in calcitonin gene-related peptide (CGRP)-positive DRG neurons. Moreover, the nerve constriction proximal to DRG caused more hypoxia than did that distal to DRG. Together, ATF3 expression in NHF-positive DRG neurons at the acute stage is a potential bio-signature of persistent pain in rat models of LR.

Clinical indicators to identify neuropathic pain in low back related leg pain: a modified Delphi study

BACKGROUND

Neuropathic pain (NP) is common in patients presenting with low back related leg pain. Accurate diagnosis of NP is fundamental to ensure appropriate intervention. In the absence of a clear gold standard, expert opinion provides a useful methodology to progress research and clinical practice. The aim of this study was to achieve expert consensus on a list of clinical indicators to identify NP in low back related leg pain.

METHODS

A modified Delphi method consisting of three rounds was designed in accordance with the Conducting and Reporting Delphi Studies recommendations. Recruitment involved contacting experts directly and through expressions of interest on social media. Experts were identified using pre-defined eligibility criteria. Priori consensus criteria were defined for each round through descriptive statistics. Following completion of round 3 a list of clinical indicators that achieved consensus were generated.

RESULTS

Thirty-eight participants were recruited across 11 countries. Thirty-five participants completed round 1 (92.1%), 32 (84.2%) round 2 and 30 (78.9%) round 3. Round 1 identified consensus (Kendall's W coefficient of concordance 0.456; p < 0.001) for 10 clinical indicators out of the original 14, and 9 additional indicators were added to round 2 following content analysis of qualitative data. Round 2 identified consensus (Kendall's W coefficient of concordance 0.749; p < 0.001) for 10 clinical indicators out of 19, and 1 additional indicator was added to round 3. Round 3 identified consensus for 8 indicators (Kendall's W coefficient of concordance 0.648; p < 0.001). Following completion of the third round, an expert derived consensus list of 8 items was generated. Two indicators; pain variously described a burning, electric shock like and/or shooting into leg and pain in association with other neurological symptoms (e.g. pins and needles, numbness, weakness), were found to have complete agreement amongst expert participants.

CONCLUSIONS

Good agreement was found for the consensus derived list of 8 clinical indicators to identify NP in low back related leg pain. This list of indicators provide some indication of the criteria upon which clinicians can identify a NP component to low back related leg pain; further research is needed for stronger recommendations to be made.

Diagnostic utility of patient history, clinical examination and screening tool data to identify neuropathic pain in low back related leg pain: a systematic review and narrative synthesis

BACKGROUND

Low back-related leg pain (LBLP) is a challenge for healthcare providers to manage. Neuropathic pain (NP) is highly prevalent in presentations of LBLP and an accurate diagnosis of NP in LBLP is essential to ensure appropriate intervention. In the absence of a gold standard, the objective of this systematic review was to evaluate the diagnostic utility of patient history, clinical examination and screening tool data for identifying NP in LBLP.

METHODS

This systematic review is reported in line with PRISMA and followed a pre-defined and published protocol. CINAHL, EMBASE, MEDLINE, Web of Science, Cochrane Library, AMED, Pedro and PubMed databases, key journals and the grey literature were searched from inception to 31 July 2019. Eligible studies included any study design reporting primary diagnostic data on the diagnostic utility of patient history, clinical examination or screening tool data to identify NP in LBLP, in an adult population. Two independent reviewers searched information sources, assessed risk of bias (QUADAS-2) and used GRADE to assess overall quality of evidence.

RESULTS

From 762 studies, 11 studies were included. Nine studies out of the 11 were at risk of bias. Moderate level evidence supports a cluster of eight signs (age, duration of disease, paroxysmal pain, pain worse in leg than back, typical dermatomal distribution, worse on coughing/sneezing/straining, finger to floor distance and paresis) for diagnosing lumbosacral nerve root compression, demonstrating moderate/high sensitivity (72%) and specificity (80%) values. Moderate level evidence supports the use of the StEP tool for diagnosing lumbar radicular pain, demonstrating high sensitivity (92%) and specificity (97%) values.

CONCLUSIONS

Overall low-moderate level evidence supports the diagnostic utility of patient history, clinical examination and screening tool data to identify NP in LBLP. The weak evidence base is largely due to methodological flaws and indirectness regarding applicability of the included studies. The most promising diagnostic tools include a cluster of 8 patient history/clinical examination signs and the StEP tool. Low risk of bias and high level of evidence diagnostic utility studies are needed, in order for stronger recommendations to be made.

The Impact of Age on the Outcomes of Minimally Invasive Lumbar Decompression for Lumbar Spinal Stenosis

Background and Purpose

Minimally invasive lumbar decompression (mild^®) is an effective long-term therapy for patients with symptomatic lumbar spinal stenosis (LSS) resulting primarily from hypertrophic ligamentum flavum (HLF). Most subjects in clinical studies of the mild procedure have been older adults (age≥65). While the incidence of LSS increases with age, a substantial number of adults (age<65) also suffer from neurogenic claudication secondary to HLF. In this report, outcomes of mild were compared between adults and older adults.

Patients and Methods

All prospective studies of the mild procedure with a 1-year follow-up completed since the beginning of 2012 that allowed the inclusion of adult patients of all ages were reviewed. Outcomes of visual analog scale (VAS), Oswestry Disability Index (ODI), Pain Disability Index (PDI), Roland Morris Low Back Pain and Disability Questionnaire (RMQ), standing time and walking distance were compared for adults and older adults.

Results

Four studies met the inclusion criteria, resulting in an analysis of 49 adults and 160 older adults. Patients in both age groups experienced significant mean improvements in all but one outcome measure at 6- and 12-month follow-up. Differences between the two age groups in all scores at 6 and 12 months were not statistically significant.

Conclusion

Analysis of the four studies indicated that symptom improvements for adults and older adults were significant from baseline, and no statistically significant difference was observed between the two age groups. These results illustrate that mild can be an effective treatment for LSS due primarily to HLF, regardless of the adult patient age.

Understanding sciatica: illness and treatment beliefs in a lumbar radicular pain population. A qualitative interview study

BACKGROUND

Several pathological processes contribute to lumbar radicular pain (LRP), commonly known as sciatica. It is not known how patients rationalise the experience of sciatica or understand the diagnosis. Providing clinicians with a better understanding of how patients conceptualise sciatica will help them to tailor information for patients on the management and treatment of the condition.

AIM

To understand patients' beliefs regarding their illness following a diagnosis of LRP, how these beliefs were developed, and the impact of illness beliefs on treatment beliefs.

DESIGN & SETTING

Qualitative interview study from a single NHS musculoskeletal interface service (in Wales, UK).

METHOD

Thirteen patients recently diagnosed with LRP were consecutively recruited. Individual semi-structured interviews were recorded and transcribed. Data were analysed using a thematic approach.

RESULTS

Four main themes were generated: (1) the illness experience (2) the concept of sciatica, (3) treatment beliefs, and (4) the desire for credible information.

CONCLUSION

The diagnosis of LRP is often communicated and understood within a compressive conceptual illness identity. Explaining symptoms with a compressive pathological model is easily understood by patients but may not accurately reflect the spectrum of pathological processes known to contribute to radicular pain. This model appears to inform patient beliefs about treatments. Clinicians should take care to fully explain the pathology prior to shared decision-making with patients.

Current challenges in diagnosis of lumbar radiculopathy

Lumbar radiculopathy (LR) is a term used to describe a pain syndrome caused by compression or irritation of nerve roots in the lower back. The surgery cost for LR increased by 23% annually during 1992-2003 in the developed country. Although it is one of most common complaints in clinical practice, the diagnosis for LR is still very challenging. Here we discuss the current tools of LR diagnosis and highlight the needs to develop new diagnosis tools for LR.

Electrophysiological characteristics of IB4-negative TRPV1-expressing muscle afferent DRG neurons

Muscle afferent neurons that express transient receptor potential vanilloid type I (TRPV1) are responsible for muscle pain associated with tissue acidosis. We have previously found that TRPV1 of isolectin B4 (IB4)-negative muscle nociceptors plays an important role in the acid-induced hyperalgesic priming and the development of chronic hyperalgesia in a mouse model of fibromyalgia. To understand the electrophysiological properties of the TRPV1-expressing muscle afferent neurons, we used whole-cell patch clamp recording to study the acid responsiveness and action potential (AP) configuration of capsaicin-sensitive neurons innervating to gastrocnemius muscle. Here we showed that IB4-negative TRPV1-expressing muscle afferent neurons are heterogeneous in terms of cell size, resting membrane potential, AP configuration, tetrodotoxin (TTX)-resistance, and acid-induced current (I_acid), as well as capsaicin-induced current (I_cap). TRPV1-expressing neurons were all acid-sensitive and could be divided into two acid-sensitive groups depending on an acid-induced sustained current (type I) or an acid-induced biphasic ASIC3-like current (type II). Type I TRPV1-expressing neurons were distinguishable from type II TRPV1-expressing neurons in AP overshoot, after-hyperpolarization duration, and all I_acid parameters, but not in AP threshold, TTX-resistance, resting membrane potential, and I_cap parameters. These differential biophysical properties of TRPV1-expressing neurons might partially annotate their different roles involved in the development and maintenance of chronic muscle pain.