Prognostic value of early computed tomography in radiculopathy due to lumbar intervertebral disk herniation. A prospective study

Inflammation in the intervertebral disc herniation

Up until fairly recently, it was thought that sciatic pain in the lumbar herniated disc was caused by compression on the nerve root. However, the lumbar herniated disc shows mixed pictures which are difficult to explain by simple mechanical compromise. In recent years various immunology, immunohistochemistry and molecular biology studies have shown that the herniated tissue is not an inert material, but rather it Is biologically very active with the capability of expressing a series of inflammatory mediators: cytokines such as interleukin-1, interleukin-6, interleuquin-8 and tumor necrosis factor being the ones which stand out. The inflammation is not only induced by the chemical irritation of the bioactive substances released by the nucleus pulposus but also by an autoimmune response against itself. Thus, in addition to the mechanical factor, the biomechanical mediation plays an important role in the pathophysiology of sciatic pain and of radiculopathy. Through a review of a wide range of literature, we researched the cellular molecular mediators involved in this inflammatory process around the lumbar herniated disc and its involvement in sciatic pain.

Can bacterial infection by low virulent organisms be a plausible cause for symptomatic disc degeneration? A systematic review

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To review and assess the current evidence from the literature on the potential association between disc infection with the development of symptomatic degenerative disc disease.

SUMMARY OF BACKGROUND DATA

The potential relationship between disc infection- and disc degeneration-related symptoms remains controversial, with contradictory evidence available in the literature. Several studies have demonstrated the presence of infected extruded nucleus tissue from first-time disc herniations, implicating the role of disc microbial infection as a pathway for disc degeneration. In contrast, other studies reported very low prevalence of bacterial infection in samples from patients with sciatica, quoting contamination as the predominant source. To summarize the available evidence to date, a systematic review and meta-analysis was conducted.

METHODS

A comprehensive search from 6 electronic databases was performed for studies investigating the potential relationship between disc infection as a cause for degenerative disc disease and symptomatic neck/back pain or radiculopathy. Random-effects meta-analysis of proportions and odds ratio with 95% confidence intervals was used to pool the available evidence.

RESULTS

Nine relevant studies involving 602 patients with degenerative disc disease or pain were identified. From 6 studies supporting the role of infection in the pathophysiology of disc degeneration, the pooled infection prevalence was 45.2% (34.5%-56.0%). Overall pooled prevalence in all studies was 36.2% (24.7%-47.7%). Proportion of disc infections was higher in patients with symptomatic disc disease than in patients without (37.4% vs. 5.9%; odds ratio, 6.1; 95% confidence intervals, 1.426-25.901). The majority of infections were due to Propionibacterium acnes in 59.6% (43.2%-76.1%).

CONCLUSION

From the limited evidence available, the possibility that disc infection may be linked with disc degeneration should not be ruled out. There is a need to investigate this further through larger, adequately powered multi-institutional studies with contaminant arm to control for specimen contamination.

LEVEL OF EVIDENCE

2.

Systematic review of prognostic factors predicting outcome in non-surgically treated patients with sciatica

Identification of prognostic factors for surgery in patients with sciatica is important to be able to predict surgery in an early stage. Identification of prognostic factors predicting persistent pain, disability and recovery are important for better understanding of the clinical course, to inform patient and physician and support decision making. Consequently, we aimed to systematically review prognostic factors predicting outcome in non-surgically treated patients with sciatica. A search of Medline, Embase, Web of Science and Cinahl, up to March 2012 was performed for prospective cohort studies on prognostic factors for non-surgically treated sciatica. Two reviewers independently selected studies for inclusion and assessed the risk of bias. Outcomes were pain, disability, recovery and surgery. A best evidence synthesis was carried out in order to assess and summarize the data. The initial search yielded 4392 articles of which 23 articles reporting on 14 original cohorts met the inclusion criteria. High clinical, methodological and statistical heterogeneity among studies was found. Reported evidence regarding prognostic factors predicting the outcome in sciatica is limited. The majority of factors that have been evaluated, e.g., age, body mass index, smoking and sensory disturbance, showed no association with outcome. The only positive association with strong evidence was found for leg pain intensity at baseline as prognostic factor for subsequent surgery.

Prognostic factors for non-success in patients with sciatica and disc herniation

BACKGROUND

Few studies have investigated prognostic factors for patients with sciatica, especially for patients treated without surgery. The aim of this study was to identify factors associated with non-success after 1 and 2 years of follow-up and to test the prognostic value of surgical treatment for sciatica.

METHODS

The study was a prospective multicentre observational study including 466 patients with sciatica and lumbar disc herniation. Potential prognostic factors were sociodemographic characteristics, back pain history, kinesiophobia, emotional distress, pain, comorbidity and clinical examination findings. Study participation did not alter treatment considerations for the patients in the clinics. Patients reported on the questionnaires if surgery of the disc herniation had been performed. Uni- and multivariate logistic regression analyses were used to evaluate factors associated with non-success, defined as Maine-Seattle Back Questionnaire score of ≥5 (0-12) (primary outcome) and Sciatica Bothersomeness Index ≥7 (0-24) (secondary outcome).

RESULTS

Rates of non-success were at 1 and 2 years 44% and 39% for the main outcome and 47% and 42% for the secondary outcome. Approximately 1/3 of the patients were treated surgically. For the main outcome variable, in the final multivariate model non-success at 1 year was significantly associated with being male (OR 1.70 [95% CI; 1.06 - 2.73]), smoker (2.06 [1.31 - 3.25]), more back pain (1.0 [1.01 - 1.02]), more comorbid subjective health complaints (1.09 [1.03 - 1.15]), reduced tendon reflex (1.62 [1.03 - 2.56]), and not treated surgically (2.97 [1.75 - 5.04]). Further, factors significantly associated with non-success at 2 years were duration of back problems >; 1 year (1.92 [1.11 - 3.32]), duration of sciatica >; 3 months (2.30 [1.40 - 3.80]), more comorbid subjective health complaints (1.10 [1.03 - 1.17]) and kinesiophobia (1.04 [1.00 - 1.08]). For the secondary outcome variable, in the final multivariate model, more comorbid subjective health complaints, more back pain, muscular weakness at clinical examination, and not treated surgically, were independent prognostic factors for non-success at both 1 and 2 years.

CONCLUSIONS

The results indicate that the prognosis for sciatica referred to secondary care is not that good and only slightly better after surgery and that comorbidity should be assessed in patients with sciatica. This calls for a broader assessment of patients with sciatica than the traditional clinical assessment in which mainly the physical symptoms and signs are investigated.

Predictors of long-term pain and disability in patients with low back pain investigated by magnetic resonance imaging: a longitudinal study

Background

It is possible that clinical outcome of low back pain (LBP) differs according to the presence or absence of spinal abnormalities on magnetic resonance imaging (MRI), in which case there could be value in using MRI findings to refine case definition of LBP in epidemiological research. We therefore conducted a longitudinal study to explore whether spinal abnormalities on MRI for LBP predict prognosis after 18 months.

Methods

A consecutive series of patients aged 20-64 years, who were investigated by MRI because of mechanical LBP (median duration of current episode 16.2 months), were identified from three radiology departments, and those who agreed completed self-administered questionnaires at baseline and after a mean follow-up period of 18.5 months (a mean of 22.2 months from MRI investigation). MRI scans were assessed blind to other clinical information, according to a standardised protocol. Associations of baseline MRI findings with pain and disability at follow-up, adjusted for treatment and for other potentially confounding variables, were assessed by Poisson regression and summarised by prevalence ratios (PRs) with their 95% confidence intervals (CIs).

Results

Questionnaires were completed by 240 (74%) of the patients who had agreed to be followed up. Among these 111 men and 129 women, 175 (73%) reported LBP in the past four weeks, 89 (37%) frequent LBP, and 72 (30%) disabling LBP. In patients with initial disc degeneration there was an increased risk of frequent (PR 1.3, 95%CI 1.0-1.9) and disabling LBP (PR 1.7, 95%CI 1.1-2.5) at follow-up. No other associations were found between MRI abnormalities and subsequent outcome.

Conclusions

Our findings suggest that the MRI abnormalities examined are not major predictors of outcome in patients with LBP. They give no support to the use of MRI findings as a way of refining case definition for LBP in epidemiological research.

Prognostic factors in non-surgically treated sciatica: a systematic review

Background

When present sciatica is considered an obstacle to recovery in low back pain patients, yet evidence is limited regarding prognostic factors for persistent disability in this patient group. The aim of this study is to describe and summarise the evidence regarding prognostic factors for sciatica in non-surgically treated cohorts. Understanding the prognostic factors in sciatica and their relative importance may allow the identification of patients with particular risk factors who might benefit from early or specific types of treatment in order to optimise outcome.

Methods

A systematic literature search was conducted using Medline, EMBASE and CINAHL electronic databases. Prospective cohort studies describing subjects with sciatica and measuring pain, disability or recovery outcomes were included. Studies of cohorts comprised entirely of surgically treated patients were excluded and mixed surgically and conservatively treated cohorts were included only if the results were analysed separately by treatment group or if the analysis was adjusted for treatment.

Results

Seven adequate or high quality eligible studies were identified. There were conflicting but mainly negative results regarding the influence of baseline pain severity, neurological deficit, nerve root tension signs, duration of symptoms and radiological findings on outcome. A number of factors including age, gender, smoking, previous history of sciatica and heaviness of work do not appear to influence outcome. In contrast to studies of low back pain and purely surgically treated sciatica cohorts, psychological factors were rarely investigated.

Conclusions

At present, the heterogeneity of the available studies makes it difficult to draw firm conclusions about sciatica prognosis, and highlights the need for further research for this group of patients. Large scale prospective studies of high methodological quality, using a well-defined, consistent definition of sciatica and investigating psychosocial factors alongside clinical and radiological findings are recommended to identify prognostic factors in this population.

How is recovery from low back pain measured? A systematic review of the literature

Recovery is commonly used as an outcome measure in low back pain (LBP) research. There is, however, no accepted definition of what recovery involves or guidance as to how it should be measured. The objective of the study was designed to appraise the LBP literature from the last 10 years to review the methods used to measure recovery. The research design includes electronic searches of Medline, EMBASE, CINAHL, Cochrane database of clinical trials and PEDro from the beginning of 1999 to December 2008. All prospective studies of subjects with non-specific LBP that measured recovery as an outcome were included. The way in which recovery was measured was extracted and categorised according to the domain used to assess recovery. Eighty-two included studies used 66 different measures of recovery. Fifty-nine of the measures did not appear in more than one study. Seventeen measures used pain as a proxy for recovery, seven used disability or function and seventeen were based on a combination of two or more constructs. There were nine single-item recovery rating scales. Eleven studies used a global change scale that included an anchor of 'completely recovered'. Three measures used return to work as the recovery criterion, two used time to insurance claim closure and six used physical performance. In conclusion, almost every study that measured recovery from LBP in the last 10 years did so differently. This lack of consistency makes interpretation and comparison of the LBP literature problematic. It is likely that the failure to use a standardised measure of recovery is due to the absence of an established definition, and highlights the need for such a definition in back pain research.

Pre-operative blood test for antibody to nucleus pulposus may distinguish types of lumbar disc herniation

The types of lumbar disc herniation not only play a key role in planning therapeutic procedure, but also appear to be connected with prognosis. However, it is difficult to distinguish the types preoperatively. To the best of our knowledge, the intervertebral disc is the largest avascular structure in the human body. Once the nucleus pulposus extrudes from the annulus fibrosus or combining with posterior longitudinal ligament, the immune system recognizes it as a foreign body, which may induce the autoimmune reaction ending with production of auto-antibody, that is so-called antibody to nucleus pulposus. The blood test for antibody to nucleus pulposus is ultimately accurate because the result is not relied upon the patient's complain but specific to herniated nucleus pulposus tissue. If this hypothesis is proved to be correct, it could be possible to improve the accuracy of distinguishing types of lumbar disc herniation just by a pre-operative blood test for antibody to nucleus pulposus.

Modified straight leg raising test: a hypothetical clinical adjunct to distinguish two types of lumbar disc herniation preoperatively

There are two anatomically different types of lumbar disc herniation, contained and noncontained. The status of disc herniation not only has a place of in planning therapeutic procedure, but also appears prognostically important. However, it is difficult to distinguish these two types completely without surgery, even by imaging studies. As a hypothetical clinical adjunct, a modified straight leg raising test is described. This novel diagnostic aid is based on the pathogenesis of sciatica, and enlightened by the mechanisms of both traditional straight leg raising test and traction. We surmise that the mechanical compression caused by herniated disc is predominant in contained type; whereas the chemical inflammatory effect is more pronounced in the pathogenesis of sciatica in noncontained type. Thus, it is hypothesized that in patients with contained type, the symptoms of sciatica, and the angles of straight leg raising test would be different before and after traction. On the other hand, in patients with noncontained type, these clinical appearances could not improve significantly. According to the different symptoms, two types of disc herniation are expected to be distinguished by the straight leg raising test preoperatively. Combined with imaging studies, this hypothetical clinical adjunct is hoped to ameliorate the accuracy of diagnosis.

The effectiveness of motorised lumbar traction in the management of LBP with lumbo sacral nerve root involvement: a feasibility study

BACKGROUND

Traction is commonly used for the treatment of low back pain (LBP), predominately with nerve root involvement; however its benefits remain to be established. The aim of this study was to test the feasibility of a pragmatic randomized controlled trial to compare the difference between two treatment protocols (manual therapy, exercise and advice, with or without traction) in the management of acute/sub acute LBP with 'nerve root' involvement.

METHODS

30 LBP patients with nerve root pain were recruited and randomly assigned to one of two treatment groups. Primary outcome measures were the: McGill pain questionnaire, Roland Morris disability questionnaire, and the SF36 Questionnaire; recorded at baseline, discharge, 3 and 6 months post-discharge.

RESULTS

27 patients completed treatment with a loss of another four patients at follow up. Intention to treat analysis demonstrated an improvement in all outcomes at follow up points but there appeared to be little difference between the groups.

CONCLUSION

This study has shown that a trial recruiting patients with 'nerve root' problems is feasible. Further research based upon a fully powered trial is required to ascertain if the addition of traction has any benefit in the management of these patients.

TRIAL REGISTRATION

REGISTRATION NUMBER

ISRCTN78417198.

Magnetic Resonance Imaging Findings as Predictors of Clinical Outcome in Patients With Sciatica Receiving Active Conservative Treatment

OBJECTIVE

The aims of this study were to investigate the possible prognostic value of disk-related magnetic resonance imaging (MRI) findings in relation to recovery at 14 months in patients with severe sciatica, and whether improvement of disk herniation and/or nerve root compromise is concurrent with recovery.

METHODS

All patients included in this prospective observational study of patients with sciatica receiving active conservative treatment were scanned at baseline and at 14 months' follow-up. Definite recovery at follow-up was defined as an absence of sciatic leg pain and a Roland Morris disability score of 3 or less. Potential predictors of interest were disk-related MRI findings in the lumbar spine. Bi- and multivariate logistic regression analyses were used to identify any predictors of recovery. Age, sex, and treatment were included in the analyses as possible confounding/modifying factors.

RESULTS

According to the definitions used, 53% of 154 patients recovered; 63% of men (n = 84) and 40% of women (n = 70). In the multivariate analyses, broad-based protrusions, extrusions, and male sex were found to be predictive of a positive outcome. Sex was identified as a true confounder in that the prevalence of disk-related MRI findings was different for men and women, and they had different recovery rates. Improvement of disk herniations and nerve root compromise over time did not coincide with definite recovery.

CONCLUSIONS

In patients with sciatica receiving active conservative treatment, broad-based protrusions and extrusions at baseline were positive predictors of definite recovery at 14 months. However, at 14 months the MRI-defined improvement of disk herniations and nerve root compromise was not correlated with definite recovery.

Pathophysiology of disk-related sciatica. I.--Evidence supporting a chemical component

Sciatica in patients with disk disease was long ascribed to pressure put on the sciatic nerve root by a herniated disk. However, a role for chemical factors acting in conjunction with this mechanical insult is suggested by a number of clinical observations: disk surgery does not consistently provide pain relief, large disk herniations are not always symptomatic, severe pain may be present in patients without imaging evidence of nerve root compression, the severity of symptoms and neurological signs is not well correlated with the size of the disk herniation, and conservative therapy is often effective. Experimental studies have provided further evidence for a chemical component: disk herniations can undergo spontaneous resorption, the intervertebral disk is immunogenic, and mediators for inflammation have been identified within intervertebral disk tissue. The current pathophysiological theory incriminates proinflammatory substances secreted by the nucleus pulposus (NP). When preexisting or concomitant mechanical injury to a nerve root occurs, these substances can cause nerve root pain. Animal experiments have established that the NP can induce functional and structural nerve root abnormalities in the absence of mechanical compression and that this effect is mediated by substances located at the surface of NP cells. Methylprednisolone, diclofenac, indomethacin, doxycycline, and cyclosporine induce variable inhibition of this effect. Available information points to tumor necrosis factor-alpha (TNF-alpha) as the main candidate among substances potentially responsible for nerve root pain. Therefore, trials of TNF-alpha antagonists in patients with disk-related sciatica are warranted.