Effect of periradicular methylprednisolone on spontaneous resorption of intervertebral disc herniations

Immune exposure: how macrophages interact with the nucleus pulposus

Intervertebral disc degeneration (IDD) is a primary contributor to low back pain. Immune cells play an extremely important role in modulating the progression of IDD by interacting with disc nucleus pulposus (NP) cells and extracellular matrix (ECM). Encased within the annulus fibrosus, healthy NP is an avascular and immune-privileged tissue that does not normally interact with macrophages. However, under pathological conditions in which neovascularization is established in the damaged disc, NP establishes extensive crosstalk with macrophages, leading to different outcomes depending on the different microenvironmental stimuli. M1 macrophages are a class of immune cells that are predominantly pro-inflammatory and promote inflammation and ECM degradation in the NP, creating a vicious cycle of matrix catabolism that drives IDD. In contrast, NP cells interacting with M2 macrophages promote disc tissue ECM remodeling and repair as M2 macrophages are primarily involved in anti-inflammatory cellular responses. Hence, depending on the crosstalk between NP and the type of immune cells (M1 vs. M2), the overall effects on IDD could be detrimental or regenerative. Drug or surgical treatment of IDD can modulate this crosstalk and hence the different treatment outcomes. This review comprehensively summarizes the interaction between macrophages and NP, aiming to highlight the important role of immunology in disc degeneration.

Selective nerve root blocks vs. caudal epidural injection for single level prolapsed lumbar intervertebral disc - A prospective randomized study

BACKGROUND

Chronic lumbar radiculopathy has a lifetime prevalence of 5.3% in men and 3.7% in women. It usually resolves spontaneously, but up to 30% cases will have pronounced symptoms even after one year.

AIMS

A prospective randomized single-blind study was conducted to compare the efficacy of caudal epidural steroid injection and selective nerve root block in management of pain and disability in cases of lumbar disc herniation.

METHODS

Eighty patients with confirmed single-level lumbar disc herniation were equally divided in two groups: (a) caudal epidural and (b) selective nerve root block group, by a computer-generated random allocation method. The caudal group received three injections of steroid mixed with local anesthetics while selective nerve root block group received single injection of steroid mixed with local anesthetic agent. Patients were assessed for pain relief and reduction in disability.

RESULTS

In SNRB group, pain reduced by more than 50% up till 6 months, while in caudal group more than 50% reduction of pain was maintained till 1 year. The reduction in ODI in SNRB group was 52.8% till 3 months, 48.6% till 6 months, and 46.7% at 1 year, while in caudal group the improvement was 59.6%, 64.6%, 65.1%, and 65.4% at corresponding follow-up periods, respectively.

CONCLUSIONS

Caudal epidural block is an easy and safe method with better pain relief and improvement in functional disability than selective nerve root block. Selective nerve root block injection is technically more demanding and has to be given by a skilled anesthetist.

RESULTS OF TREATMENT OF ACUTE LUMBAR DISC HERNIATION WITH TRANSFORAMINAL NERVE ROOT BLOCK

ABSTRACT Objective: To determine the efficacy of anesthetic transforaminal nerve root block in patients with sciatica secondary to lumbar disc herniation through a prospective observational study. Methods: The study included 176 patients from a private clinic undergoing transforaminal injection performed by a single spinal surgeon. The patients were assessed after two weeks, three months and six months regarding to the improvement of the pain radiating to the lower limbs. In case of persistent symptoms, patients could choose to perform a new nerve root block and maintenance of physical therapy or be submitted to conventional microdiscectomy. Results: By the end of six-month follow-up of the 176 patients, 116 had a favorable outcome (95 after one block and 21 after two blocks), and only 43 required surgery. Conclusion: The results of our study suggest a positive effect of transforaminal block for the treatment of sciatica in patients with lumbar disc herniation.

LUMBAR DISC HERNIATION

Lumbar disc herniation is the most common diagnosis among the degenerative abnormalities of the lumbar spine (affecting 2 to 3% of the population), and is the principal cause of spinal surgery among the adult population. The typical clinical picture includes initial lumbalgia, followed by progressive sciatica. The natural history of disc herniation is one of rapid resolution of the symptoms (four to six weeks). The initial treatment should be conservative, managed through medication and physiotherapy, sometimes associated with percutaneous nerve root block. Surgical treatment is indicated if pain control is unsuccessful, if there is a motor deficit greater than grade 3, if there is radicular pain associated with foraminal stenosis, or if cauda equina syndrome is present. The latter represents a medical emergency. A refined surgical technique, with removal of the extruded fragment and preservation of the ligamentum flavum, resolves the sciatic symptoms and reduces the risk of recurrence over the long term.

Combination pharmacotherapy for the treatment of neuropathic pain in adults

BACKGROUND

Pharmacotherapy remains an important modality for the treatment of neuropathic pain. However, as monotherapy current drugs are associated with limited efficacy and dose-related side effects. Combining two or more different drugs may improve analgesic efficacy and, in some situations, reduce overall side effects (e.g. if synergistic interactions allow for dose reductions of combined drugs).

OBJECTIVES

This review evaluated the efficacy, tolerability and safety of various drug combinations for the treatment of neuropathic pain.

SEARCH METHODS

We identified randomised controlled trials (RCTs) of various drug combinations for neuropathic pain from CENTRAL, MEDLINE, EMBASE and handsearches of other reviews and trial registries. The most recent search was performed on 9 April 2012.

SELECTION CRITERIA

Double-blind, randomised studies comparing combinations of two or more drugs (systemic or topical) to placebo and/or at least one other comparator for the treatment of neuropathic pain.

DATA COLLECTION AND ANALYSIS

Data extracted from each study included: proportion of participants a) reporting ≥ 30% pain reduction from baseline OR ≥ moderate pain relief OR ≥ moderate global improvement; b) dropping out of the trial due to treatment-emergent adverse effects; c) reporting each specific adverse effect (e.g. sedation, dizziness) of ≥ moderate severity. The primary comparison of interest was between study drug(s) and one or both single-agent comparators. We combined studies if they evaluated the same drug class combination at roughly similar doses and durations of treatment. We used RevMan 5 to analyse data for binary outcomes.

MAIN RESULTS

We identified 21 eligible studies: four (578 participants) evaluated the combination of an opioid with gabapentin or pregabalin; two (77 participants) evaluated an opioid with a tricyclic antidepressant; one (56 participants) of gabapentin and nortriptyline; one (120 participants) of gabapentin and alpha-lipoic acid, three (90 participants) of fluphenazine with a tricyclic antidepressant; three (90 participants) of an N-methyl-D-aspartate (NMDA) blocker with an agent from a different drug class; five (604 participants) of various topical medications; one (313 participants) of tramadol with acetaminophen; and another one (44 participants) of a cholecystokinin blocker (L-365,260) with morphine. The majority of combinations evaluated to date involve drugs, each of which share some element of central nervous system (CNS) depression (e.g. sedation, cognitive dysfunction). This aspect of side effect overlap between the combined agents was often reflected in similar or higher dropout rates for the combination and may thus substantially limit the utility of such drug combinations. Meta-analysis was possible for only one comparison of only one combination, i.e. gabapentin + opioid versus gabapentin alone. This meta-analysis involving 386 participants from two studies demonstrated modest, yet statistically significant, superiority of a gabapentin + opioid combination over gabapentin alone. However, this combination also produced significantly more frequent side effect-related trial dropouts compared to gabapentin alone.

AUTHORS' CONCLUSIONS

Multiple, good-quality studies demonstrate superior efficacy of two-drug combinations. However, the number of available studies for any one specific combination, as well as other study factors (e.g. limited trial size and duration), preclude the recommendation of any one specific drug combination for neuropathic pain. Demonstration of combination benefits by several studies together with reports of widespread clinical polypharmacy for neuropathic pain surely provide a rationale for additional future rigorous evaluations. In order to properly identify specific drug combinations which provide superior efficacy and/or safety, we recommend that future neuropathic pain studies of two-drug combinations include comparisons with placebo and both single-agent components. Given the apparent adverse impact of combining agents with similar adverse effect profiles (e.g. CNS depression), the anticipated development and availability of non-sedating neuropathic pain agents could lead to the identification of more favourable analgesic drug combinations in which side effects are not compounded.

Spontaneous resorption of sequestrated intervertebral disc herniation

OBJECTIVE

The aim of this study is to describe six cases with spontaneous resorption of sequestrated intervertebral disc herniation observed using magnetic resonance imaging. In addition, the possible mechanisms, predictive factors of spontaneous disappearance of the sequestrated disc herniation, and the proper surgical timing were discussed and reviewed in literature.

METHODS

All the studied cases experienced acute radicular pain due to sequestrated intervertebral disc herniation; they refused surgery and were treated conservatively, and they were followed up neurologically and radiologically in the outpatient clinic in regular visits.

RESULTS

The studied cases included five cases with lumbar disc herniation (three at level L4-5 and two at level L5-S1) and one case with cervical disc herniation at level C5-6. All patients recovered from their radicular pain within 3 to 6 weeks, and it was correlated with resorption of their sequestrated intervertebral disc herniation as documented in their follow-up magnetic resonance imaging at 4 to 9 months.

CONCLUSIONS

We found that sequestrated disc herniation has potential for regression, which can be clearly demonstrated by magnetic resonance imaging, because of having higher water content, and therefore, may regress through both dehydration and inflammation-mediated resorption. We suggest conservative treatment in the initial course of the sequestrated type of disc herniation for at least 2 months before recommending surgical intervention unless severe neurologic deterioration takes place.

Effect of caudal epidural steroid or saline injection in chronic lumbar radiculopathy: multicentre, blinded, randomised controlled trial

OBJECTIVE

To assess the efficacy of caudal epidural steroid or saline injection in chronic lumbar radiculopathy in the short (6 weeks), intermediate (12 weeks), and long term (52 weeks).

DESIGN

Multicentre, blinded, randomised controlled trial.

SETTING

Outpatient multidisciplinary back clinics of five Norwegian hospitals.

PARTICIPANTS

Between October 2005 and February 2009, 461 patients assessed for inclusion (presenting with lumbar radiculopathy >12 weeks). 328 patients excluded for cauda equina syndrome, severe paresis, severe pain, previous spinal injection or surgery, deformity, pregnancy, ongoing breast feeding, warfarin therapy, ongoing treatment with non-steroidal anti-inflammatory drugs, body mass index >30, poorly controlled psychiatric conditions with possible secondary gain, and severe comorbidity.

INTERVENTIONS

Subcutaneous sham injections of 2 mL 0.9% saline, caudal epidural injections of 30 mL 0.9% saline, and caudal epidural injections of 40 mg triamcinolone acetonide in 29 mL 0.9% saline. Participants received two injections with a two week interval.

MAIN OUTCOME MEASURES

Primary: Oswestry disability index scores. Secondary: European quality of life measure, visual analogue scale scores for low back pain and for leg pain.

RESULTS

Power calculations required the inclusion of 41 patients per group. We did not allocate 17 of 133 eligible patients because their symptoms improved before randomisation. All groups improved after the interventions, but we found no statistical or clinical differences between the groups over time. For the sham group (n = 40), estimated change in the Oswestry disability index from the adjusted baseline value was -4.7 (95% confidence intervals -0.6 to -8.8) at 6 weeks, -11.4 (-6.3 to -14.5) at 12 weeks, and -14.3 (-10.0 to -18.7) at 52 weeks. For the epidural saline intervention group (n = 39) compared with the sham group, differences in primary outcome were -0.5 (-6.3 to 5.4) at 6 weeks, 1.4 (-4.5 to 7.2) at 12 weeks, and -1.9 (-8.0 to 4.3) at 52 weeks; for the epidural steroid group (n=37), corresponding differences were -2.9 (-8.7 to 3.0), 4.0 (-1.9 to 9.9), and 1.9 (-4.2 to 8.0). Analysis adjusted for duration of leg pain, back pain, and sick leave did not change this trend.

CONCLUSIONS

Caudal epidural steroid or saline injections are not recommended for chronic lumbar radiculopathy. Trial registration Current Controlled Trials ISRCTN No 12574253.

Influence of cytokine inhibitors on concentration and activity of MMP-1 and MMP-3 in disc herniation

Introduction

Spontaneous resorption of disc herniation (DH) after sciatica is well documented. The matrix metalloproteinases (MMP)-1 and MMP-3 are enzymes potentially involved in this process. Glucocorticoid injections are commonly used for treatment, and other anti-inflammatory molecules like tumor necrosis factor (TNF) inhibitors are under clinical investigation. However, little is known about the effect of these molecules on DH resorption.

Methods

DH tissue was harvested from patients undergoing surgery for sciatica. Samples were thoroughly washed. Diced explants were cultured ex-vivo in 1) 0.5 ml Dulbecco's modified Eagle's medium (DMEM) 10% fetal calf serum (FCS), (controls), 2) recombinant interleukin 1 receptor antagonist (IL-1Ra), (100 ng/ml), 3) dexamethasone (10E-5 M), or 4) TNF inhibitor monoclonal antibody (10 μg/ml). Supernatants were harvested at 48 hours and frozen. Immunocapture activity assays determined total MMP activity, active MMP levels and pro-MMP levels.

Results

Fourteen DH tissue samples were analysed. Levels of all forms of MMP-3 were higher than the respective levels of MMP-1(P < 0.01). In particular, the median (interquartile range [IQR]) total MMP-3 level was 0.97 (0.47 - 2.19) ng/mg of tissue compared to 0.024 (0.01 - 0.07) ng/mg of total MMP-1 level (P < 0.01). Incubation with IL-1Ra, dexamethasone, or TNF inhibitors significantly decreased levels of all forms of MMP-3 (P < 0.05). Dexamethasone significantly decreased the ratio of active MMP-3 to total MMP-3 activity. A significant inhibitory effect of dexamethasone was observed only on active MMP-1, while IL-1 and TNF inhibitor had no significant effect on any form.

Conclusions

MMP-3 appears to play a greater role than MMP-1 in DH resorption. Dexamethasone, IL-1-Ra and TNF inhibitor decreased active MMP-3, indicating that the clinical use of these drugs may affect the resorption of DH under certain conditions.

Corticosteroids in peri-radicular infiltration for radicular pain: a randomised double blind controlled trial. One year results and subgroup analysis

The objective of this study is to evaluate the efficacy of corticosteroids in patients with radicular pain due to lumbar disc herniation or lumbar spinal stenosis through a prospective randomised, double blind controlled trial, and whether there was an effect on subsequent interventions such as additional root blocks or surgery. Peri-radicular infiltration of corticosteroids has previously been shown to offer no additional benefit in patients with sciatica compared to local anaesthetic alone. It is not known if the response to peri-radicular infiltration is less marked in certain subgroups of patients such as those with radicular pain due to lumbar spinal stenosis. Previous studies have suggested that peri-radicular infiltration of corticosteroids may obviate the need for subsequent interventions and we therefore further investigated this in the current study. We randomised 150 patients to receive a single injection with either bupivacaine alone or bupivacaine and methylprednisolone. Patients were assessed at 6 weeks and 3 months after the injection using standard outcome measures including Oswestry Disability Index (ODI), visual analogue score for leg pain and patient's subjective assessment of outcome. At 1-year follow-up, we looked at the outcome in terms of the need for subsequent interventions such as additional root blocks or surgery. At 3-month follow-up, there was no statistically significant difference in the standard outcome measures between the two injection groups. At a minimum 1-year post injection, there was no difference in the need for subsequent interventions in either group. Patients with lumbar spinal stenosis had a less marked reduction in the ODI at 3 months with a mean change of 3.3 points when compared with 15 points for patients with lumbar disc herniation. In conclusion, peri-radicular infiltration of corticosteroids for sciatica does not provide any additional benefit when compared to local anaesthetic injection alone. Corticosteroids do not obviate the need for subsequent interventions such as additional root blocks or surgery.

Timing of surgery for sciatica: subgroup analysis alongside a randomized trial

Surgery speeds up recovery for sciatica. Prolonged conservative care with surgery for those patients with persistent sciatica however, yields similar results at 1 year. To investigate whether baseline variables modify the difference in recovery rates between these treatment strategies, baseline data of 283 patients enrolled in a randomized trial, comparing early surgery with prolonged conservative care, were used to analyse effect modification of the allotted treatment strategy. For predictors shown to modify the effect of the treatment strategy, repeated measurement analyses with the Roland Disability Questionnaire and visual analogue scale pain as continuous outcomes were performed for every level of that predictor. Presumed predictive variables did not have any interaction with treatment, while “sciatica provoked by sitting” showed to be a significant effect modifier (P = 0.07). In a Cox model we estimated a hazard ratio (HR, surgery versus conservative) of 2.2 (95% CI 1.7–3.0) in favour of surgery when sciatica was provoked by sitting, while the HR was 1.3 (95% CI 0.8–2.2) when this sign was absent. The interaction effect is marginally significant (interactions are usually tested at the 10% level) but the patterns generated by the repeated measurement analyses of all primary outcomes are completely consistent with the inferred pattern from the survival analysis. Classical signs did not show any contribution as decision support tools in deciding when to operate for sciatica, whereas treatment effects of early surgery are emphasized when sciatica is provoked by sitting and negligible when this symptom is absent.

The effect of infliximab, a monoclonal antibody against TNF-alpha, on disc herniation resorption: a randomized controlled study

STUDY DESIGN

Randomized, controlled study.

OBJECTIVE

To evaluate the effect of infliximab on herniated nucleus pulposus (HNP) resorption.

SUMMARY OF BACKGROUND DATA

Although the effects of tumor necrosis factor alpha (TNF-alpha) on HNP resorption are not fully understood, TNF-alpha appears to be an essential mediator in HNP resorption.

METHODS

As part of a substudy of the FIRST II study, magnetic resonance images (MRIs) were obtained from 21 patients who were candidates for discectomy at weeks 0, 2, 12, and 26 after receiving a single infusion of either 5 mg/kg infliximab (11 patients) or placebo (10 patients). The volume (mm3) of HNP, thickness (mm) and extent (%) of rim enhancement, and presence of nerve root edema were assessed.

RESULTS

HNP volume decreased significantly from baseline to 6 months in both treatment groups (P < 0.01), with no difference noted between the infliximab and placebo groups. By week 2, rim enhancement thickness increased significantly in the infliximab group compared with the placebo group (P = 0.003). Two patients in each group required back surgery before the 6-month assessment.

CONCLUSIONS

Infliximab did not appear to interfere with disc herniation resorption over a 6-month period.

Determinants of spontaneous resorption of intervertebral disc herniations

STUDY DESIGN

A follow-up of disc herniation (herniated nucleus pulposus [HNP]) resorption on magnetic resonance imaging (MRI).

OBJECTIVE

To assess the determinants of resorption of HNP.

SUMMARY OF BACKGROUND DATA

Neovascularization in the outermost areas of HNP, presenting as an enhancing rim in gadolinium diethylenetriamine pentaacetic acid MR images, is thought to be a major determinant of spontaneous resorption of HNP.

METHODS

Patients with HNP-induced sciatica at baseline were rescanned at 2 months (N = 74) and after 12 months (N = 53). The volume of HNP (mm), thickness (mm) and extent (%) of enhancement, and the degree of HNP migration (Komori classification) were analyzed. Repeated measures analysis of covariance was used in statistical analysis.

RESULTS

Significant resorption of HNP occurred from baseline to 2 months, although the resorption rate was more pronounced over the whole 1-year follow-up. Higher baseline scores of rim enhancement thickness, higher degree of HNP displacement in the Komori classification, and age category 41-50 years were associated with a higher resorption rate. Thickness of rim enhancement was a stronger determinant of spontaneous resorption than extent of rim enhancement. Clinical symptom alleviation occurs concordantly with a faster resorption rate.

CONCLUSIONS

MRI is a useful prognostic tool for identifying patients with HNP-induced sciatica with a benign natural course.

Lumbar disc herniations: surgical versus nonsurgical treatment

Lumbar disc herniation is among the most common causes of lower-back pain and sciatica. The cause(s) of lumbar disc herniation and the relation of lumbar disc herniation to back pain and sciatica have not been fully elucidated, but most likely comprise a complex combination of mechanical and biologic processes. Furthermore, the natural history of lumbar disc herniation seems generally to be favorable, leaving the optimum treatment for lumbar disc herniation a debate in the literature. Various nonoperative and operative treatment strategies have been tried with varying degrees of success. Treatment often involves patient education, physical therapy, alternative medicine options, and pharmaco-therapy. If these fail, surgical intervention is usually recommended. A literature search was conducted to evaluate the currently known effectiveness of traditional and novel non-operative and surgical techniques for the treatment lumbar disc herniation and to determine if there are substantive new advantages in these newer contemporary treatments or combinations thereof. A structured approach to treatment of a patient who may have a symptomatic lumbar disc herniation is presented, based on analysis of the current literature. No one method of nonoperative or operative treatment would seem definitively to be superior to another. Appropriate multidisciplinary treatment including behavioral analysis and support may offer the hope of improved outcomes for patients with lumbar disc herniation.

LEVEL OF EVIDENCE

Level V (expert opinion). See the Guidelines for Authors for a complete description of the levels of evidence.

Genetic variations in IL6 associate with intervertebral disc disease characterized by sciatica

Intervertebral disc disease (IDD) characterized by sciatica is a common disorder affecting about 5% of individuals. Environmental factors can predispose to this disease, but IDD has a strong genetic background. Recent evidence suggests that inflammation is one of the key factors in the etiology of IDD. Here, a possible role of the inflammatory mediator genes was studied in 155 patients with IDD-related sciatica and 179 controls. Forty-eight patients were analyzed for mutations in the IL1A, IL1B, IL6 and TNFA genes, and 16 polymorphisms in 10 candidate cytokine genes (IL1A, IL1B, IL1RN, TNFA, IL2, IL4, IL4R, IL6, IL10, IFNG) were genotyped from all subjects. No disease-causing mutations were identified in IL1A, IL1B, IL6 or TNFA. Allele frequencies were, however, significantly different between the two groups for IL6 SNP, T15A in exon 5 (P=0.007). Furthermore, the genotypes AA and AT of the exon 5 SNP were more common in the patients (P=0.011; OR=4.4, 95% CI=1.2-15.7; AR=7.5%, 1.6-13.1%). Haplotypes were then generated for four IL6 SNPs, G-597A, G-572C, G-174C, and T15A in exon 5. Haplotype GGGA was more common in the patients (P=0.011; OR=4.8, 95% CI=1.6-14.5). To evaluate attributable risk, haplotype pairs were assigned for the individuals. The presence of GGGA/GGGA or GGGA/other genotypes had an OR of 5.4 (95% CI=1.5-19.2). Association of GGGA with disease was highly significant (P=0.0033), and the associated AR was 6.8% (1.9-11.5%). These findings support the role of IL-6 genetic variations in discogenic pain.

Efficacy of infliximab for disc herniation-induced sciatica: one-year follow-up

STUDY DESIGN

An open-label trial.

OBJECTIVES

To test the long-term efficacy of infliximab, a monoclonal antibody against tumor necrosis factor-alpha (TNF-alpha), in disc herniation-induced sciatica.

SUMMARY OF BACKGROUND DATA

Our recent trial indicated that a single infusion of 3 mg/weight-kg of infliximab produced a rapid curative effect in disc herniation-induced sciatica. Here, we describe the 1-year effect of a 3 mg/kg of infliximab in these 10 patients and our experience with a lower dose of 1 mg/kg of infliximab for the same indication in 2 additional patients.

METHODS

Patients with severe sciatica were treated with a single infusion of infliximab, 3 mg/weight-kg in 10 patients and 1 mg/kg in 2 patients, intravenously over 2 hours. The outcomes (leg and back pain on a 100-mm visual scale, Oswestry disability, clinical signs) were assessed at 1 week, 2 weeks, 1 month, 3 months, 6 months, and 1 year after the infusion. The outcomes with 3 mg/kg of infliximab were compared to 62 patients who received periradicular saline for sciatica in a previous trial. The resorption rate of disc herniations from baseline to 1 year was compared between infliximab and control groups.

RESULTS

The response to 1 mg/kg of infliximab for leg pain was good only in 1 of the 2 patients treated, whereas the response to 3 mg/kg of infliximab for leg pain was sustained in most patients over the 1-year follow-up. The 1-year response significantly favored 3 mg/kg of infliximab over periradicular saline in leg pain (P = 0.005) and disability (P = 0.003). Neurologic abnormalities normalized more comprehensively in the infliximab group (P = 0.001). Reduction in disc herniation volume did not differ between the infliximab-treated patients and controls.

CONCLUSIONS

The results showed that the beneficial effect of a single infusion of 3 mg/kg of infliximab for herniation-induced sciatica is sustained in most patients over a 1-year follow-up period. Furthermore, infliximab does not seem to interfere with the spontaneous resorption of disc herniations.