Inflammatory cells, motor weakness, and straight leg raising in transligamentous disc herniations

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.

Clinical research for whether the Traditional Chinese medicine could promote the resorption of lumbar disc herniation: a randomized controlled trial

Lumbar disc herniation (LDH) is a common, disabling musculoskeletal disorder. Magnetic resonance imaging has clarified the natural history of lumbar disc lesions and has documented that disc lesions can become smaller and can even be completely resorbed. Previous studies have confirmed that some traditional Chinese medicine (TCM) therapies can promote resorption of the protrusion. However, high-quality research evidence is needed to support the effectiveness of the protocol.

OBJECTIVE

This clinical trial aims to establish whether TCM can promote the resorption of LDH and to assess the efficacy of such therapy for LDH, thereby evaluating its clinical effect.

METHODS

The present study design is for a single-center, 2-arm, open-label randomized controlled trial. A total of 150 eligible LDH patients will be randomly assigned to either a TCM treatment group or a control group in a 1:1 ratio. Patients in the TCM group will be administered a TCM decoction for 4 weeks. Patients in the conventional drug control group will be instructed to take a specific daily dose of celecoxib. The primary outcome measure is the change from baseline in the volume of the protrusion, as assessed using MR images. Secondary outcome measures include visual analog scale pain scores and Japanese Orthopaedic Association scores assessed at 3 and 6 months.

DISCUSSION

The design and methodological rigor of this trial will allow evaluation of the basic clinical efficacy and safety data for TCM in the treatment of patients with LDH. The trial will also assess whether TCM can promote the resorption of LDH. This research will therefore help provide a solid foundation for the clinical treatment of LDH and for future research in TCM therapy.

TRIAL REGISTRATION

ChiCTR1900022377.

Physical disruption of intervertebral disc promotes cell clustering and a degenerative phenotype

To test the hypothesis that physical disruption of an intervertebral disc disturbs cell-matrix binding, leading to cell clustering and increased expression of matrix degrading enzymes that contribute towards degenerative disc cell phenotype. Lumbar disc tissue was removed at surgery from 21 patients with disc herniation, 11 with disc degeneration, and 8 with adolescent scoliosis. 5 μm sections were examined with histology, and 30-µm sections by confocal microscopy. Antibodies were used against integrin α5beta1, matrix metalloproteinases (MMP) 1, MMP-3, caspase 3, and denatured collagen types I and II. Spatial associations were sought between cell clustering and various degenerative features. An additional, 11 non-herniated human discs were used to examine causality: half of each specimen was cultured in a manner that allowed free 'unconstrained' swelling (similar to a herniated disc in vivo), while the other half was cultured within a perspex ring that allowed 'constrained' swelling. Changes were monitored over 36 h using live-cell imaging. 1,9-Di-methyl methylene blue (DMMB) assay for glycosaminoglycan loss was carried out from tissue medium. Partially constrained specimens showed little swelling or cell movement in vitro. In contrast, unconstrained swelling significantly increased matrix distortion, glycosaminoglycan loss, exposure of integrin binding sites, expression of MMPs 1 and 3, and collagen denaturation. In the association studies, herniated disc specimens showed changes that resembled unconstrained swelling in vitro. In addition, they exhibited increased cell clustering, apoptosis, MMP expression, and collagen denaturation compared to 'control' discs. Results support our hypothesis. Further confirmation will require longitudinal animal experiments.

Up-regulation of circulating microRNA-17 is associated with lumbar radicular pain following disc herniation

Background

Previous studies suggest that regulatory microRNAs (miRs) may modulate neuro-inflammatory processes. The purpose of the present study was to examine the role of miR-17 following intervertebral disc herniation.

Methods

In a cohort of 97 patients with leg pain and disc herniation verified on MRI, we investigated the association between circulating miR-17 and leg pain intensity. A rat model was used to examine possible changes in miR-17 expression in nucleus pulposus (NP) associated with leak of NP tissue out of the herniated disc. The functional role of miR-17 was addressed by transfection of miR-17 into THP-1 cells (human monocyte cell line).

Results

An association between the level of miR-17 in serum and the intensity of lumbar radicular pain was shown. Up-regulation of miR-17 in the rat NP tissue when applied onto spinal nerve roots and increased release of TNF following transfection of miR-17 into THP-1 cells were also observed. Hence, our data suggest that miR-17 may be involved in the pathophysiology underlying lumbar radicular pain after disc herniation.

Conclusions

We conclude that miR-17 may be associated with the intensity of lumbar radicular pain after disc herniation, possibly through a TNF-driven pro-inflammatory mechanism.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1967-y) contains supplementary material, which is available to authorized users.

Changes in Nerve Growth Factor Expression and Macrophage Phenotype Following Intervertebral Disc Injury in Mice

Nerve growth factor (NGF) is increased in intervertebral discs (IVDs) after disc injury and anti-NGF therapy improves low back pain in humans. Furthermore, M1 and M2 macrophage subtypes play a role in degenerative IVD injury. We examined M1 and M2 macrophage markers and NGF and cytokine expression in IVD-derived cells from control and IVD-injured mice for 28 days following injury. Ngf messenger RNA (mRNA) expression was increased 1 day after injury in injured compared with control mice, and persisted for up to 28 days. Flow cytometric analysis demonstrated that the proportion of F4/80+ CD11b+ cells was significantly increased from 1 day after injury for up to 28 days in injured compared to control mice. mRNA expression of M1 macrophage markers Tnfa, Il1b, and Nos2 was significantly increased 1 day after injury in injured compared to control mice, before gradually decreasing. At 28 days, no significant difference was observed in M1 markers. The M2a marker, Ym1, was significantly increased 1 day after injury in injured compared with control mice, while M2a and M2c markers Tgfb and Cd206 were significantly increased 7, 14, and 28 days after injury. Tumor necrosis factor α (TNF-α) and transforming growth factor β (TGF-β) stimulated Ngf mRNA and NGF protein expression in IVD cells. Our results suggest that TNF-α and TGF-β may stimulate NGF production under inflammatory and non-inflammatory conditions following IVD injury. As TNF-α and TGF-β are produced by M1 and M2 macrophages, further investigations are needed to reveal the role of macrophages in NGF expression following IVD injury. Our results may aid in developing treatments for IVD-related LBP pathology. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1798-1804, 2019.

Nerves and blood vessels in degenerated intervertebral discs are confined to physically disrupted tissue

Nerves and blood vessels are found in the peripheral annulus and endplates of healthy adult intervertebral discs. Degenerative changes can allow these vessels to grow inwards and become associated with discogenic pain, but it is not yet clear how far, and why, they grow in. Previously we have shown that physical disruption of the disc matrix, which is a defining feature of disc degeneration, creates free surfaces which lose proteoglycans and water, and so become physically and chemically conducive to cell migration. We now hypothesise that blood vessels and nerves in degenerated discs are confined to such disrupted tissue. Whole lumbar discs were obtained from 40 patients (aged 37-75 years) undergoing surgery for disc herniation, disc degeneration with spondylolisthesis or adolescent scoliosis ('non-degenerated' controls). Thin (5-μm) sections were stained with H&E and toluidine blue for semi-quantitative assessment of blood vessels, fissures and proteoglycan loss. Ten thick (30-μm) frozen sections from each disc were immunostained for CD31 (an endothelial cell marker), PGP 9.5 and Substance P (general and nociceptive nerve markers, respectively) and examined by confocal microscopy. Volocity image analysis software was used to calculate the cross-sectional area of each labelled structure, and its distance from the nearest free surface (disc periphery or internal fissure). Results showed that nerves and blood vessels were confined to proteoglycan-depleted regions of disrupted annulus. The maximum distance of any blood vessel or nerve from the nearest free surface was 888 and 247 μm, respectively. Blood vessels were greater in number, grew deeper, and occupied more area than nerves. The density of labelled blood vessels and nerves increased significantly with Pfirrmann grade of disc degeneration and with local proteoglycan loss. Analysing multiple thick sections with fluorescent markers on a confocal microscope allows reliable detection of thin filamentous structures, even within a dense matrix. We conclude that, in degenerated and herniated discs, blood vessels and nerves are confined to proteoglycan-depleted regions of disrupted tissue, especially within annulus fissures.

Evaluation of ceruloplasmin levels in patients with lumbar disc herniation

BACKGROUND

Chronic inflammation is believed to have a role in the development of lumbar disc herniation (LDH). Ceruloplasmin (CP), an acute phase protein, is known to limit inflammation.

OBJECTIVE

To evaluate CP levels in patients with LDH.

METHODS

Thirty-five patients with LDH and 35 healthy individuals were enrolled in the study. Participants were divided into two groups; group 1 (n = 35) consisted of patients with LDH, and group 2 (n = 35) consisted of healthy subjects. Surgery specimens were taken from all patients who underwent LDH-related surgery. CP levels were measured in both blood and tissue samples. Pain intensity was evaluated using a visual analog scale (VAS).

RESULTS

There were no significant differences in gender, age, or body mass index between the control and LDH patients (p > 0.05 for all). Compared with the control patients, LDH patients had significantly higher serum CP levels (p < 0.001). In LDH patients, tissue CP levels were significantly higher than serum levels (p < 0.001). According to bivariate analysis, the serum CP levels were significantly correlated with the VAS score in group 1 (r = 0.491, p = 0.003).

CONCLUSIONS

The present study showed that CP levels increased in both the serum and the tissues of patients with LDH compared to patients without LDH, possibly as a consequence of LDH-associated inflammation.

Plasmacytoid dendritic cells and memory T cells infiltrate true sequestrations stronger than subligamentous sequestrations: evidence from flow cytometric analysis of disc infiltrates

PURPOSE

Herniated nucleus pulposus has been considered to induce an adaptive immune response. Antigen recognition by antigen-presenting-cells (APCs) represents an important step within manifestation of an adaptive immune response. Macrophages have been assumed to function as APC, while importance of plasmacytoid dendritic cells for initiation of an immune response directed towards herniated nucleus pulposus has never been examined. The aim of the present study was to assess importance of plasmacytoid dendritic cells for initiation of immune response directed towards herniated discs.

METHODS

Fifteen patients with true sequestrations and three patients with subligamentous sequestrations underwent surgery after their neurological examinations. Disc material was harvested, weighted and digested for 90 min. Separated single cells were counted, stained for plasmacytoid dendritic cells (CD123(+)CD4(+)), macrophages (CD14(+)CD11c(+)) and memory T cells (CD4(+)CD45RO(+)) and analysed by flow cytometry. Both patient groups were compared in cell proportions. Furthermore, patients with true sequestrations (TRUE patients) were subdivided into subgroups based on severity of muscle weakness and results in straight leg raising (SLR) test. Subgroups were compared in cell proportions.

RESULTS

Plasmacytoid dendritic cells and memory T cells infiltrated true sequestrations stronger than the subligamentous sequestration and plasmacytoid dendritic cells predominated over macrophages in true sequestrations. Highest proportions of plasmacytoid dendritic cells were detected in infiltrates of patients having true sequestrations, severe muscle weakness and negative result in SLR test.

CONCLUSIONS

The findings of the present study indicate that plasmacytoid dendritic cells are involved in initiation of an immune response directed towards herniated nucleus pulposus, while macrophages may reinforce the manifested immune response and mediate disc resorption.

Do intervertebral discs degenerate before they herniate, or after?

The belief that an intervertebral disc must degenerate before it can herniate has clinical and medicolegal significance, but lacks scientific validity. We hypothesised that tissue changes in herniated discs differ from those in discs that degenerate without herniation. Tissues were obtained at surgery from 21 herniated discs and 11 non-herniated discs of similar degeneration as assessed by the Pfirrmann grade. Thin sections were graded histologically, and certain features were quantified using immunofluorescence combined with confocal microscopy and image analysis. Herniated and degenerated tissues were compared separately for each tissue type: nucleus, inner annulus and outer annulus.

Herniated tissues showed significantly greater proteoglycan loss (outer annulus), neovascularisation (annulus), innervation (annulus), cellularity/inflammation (annulus) and expression of matrix-degrading enzymes (inner annulus) than degenerated discs. No significant differences were seen in the nucleus tissue from herniated and degenerated discs. Degenerative changes start in the nucleus, so it seems unlikely that advanced degeneration caused herniation in 21 of these 32 discs. On the contrary, specific changes in the annulus can be interpreted as the consequences of herniation, when disruption allows local swelling, proteoglycan loss, and the ingrowth of blood vessels, nerves and inflammatory cells.

In conclusion, it should not be assumed that degenerative changes always precede disc herniation.

Cite this article: Bone Joint J 2013;95-B:1127–33.

Analysis and prevalence of inflammatory cells in subtypes of lumbar disc herniations under cyclooxygenase-2 inhibitor therapy

OBJECTIVE

The aim of the present study was to analyse inflammatory cells in lumbar disc tissue under cyclooxygenase-2 (COX-2) inhibitor therapy, to detect their prevalence in different subtypes of lumbar disc herniations and to assess the influence of inflammatory reactions in herniated disc tissue on postoperative outcome.

METHODS

In this prospective study, intervertebral disc specimens were obtained from 50 patients. All the patients were given COX-2 inhibitor therapy (Rofecoxib) 25 mg/day for 10 days before surgery. The herniated disc specimens were routinely fixed in a 10% buffered formaline solution and paraffin-embedded; 5 microm thin sections were stained with monoclonal antibodies CD-68 for macrophages, CD-45 RO for T cells and CD-20 for B cells. The specimens were microscopically examined and classified by two independent examiners in a blinded manner.

RESULTS

CD-68 macrophages were evident in herniated lumbar disc tissue in 40% of the cases, but abundant inflammation was observed in only 18% of the cases. Macrophages were significantly common in sequesters with a prevalence of 80%, and no macrophages were observed in the protrusions. We obtained the best outcome scores in the patients with a sequestrated lumbar disc herniation.

CONCLUSION

Although most of the specimens from all the patients showed no significant inflammatory reaction, maybe due to COX-2 inhibitor therapy, they all needed surgery with no relief of the symptoms despite conservative therapy. Nerve root compression still seems to be the leading pathomechanism.

Intervertebral disc and macrophage interaction induces mechanical hyperalgesia and cytokine production in a herniated disc model in rats

OBJECTIVE

The expression of proinflammatory factors such as tumor necrosis factor α (TNFα), interleukin-6 (IL-6), IL-8, and prostaglandin E(2) (PGE(2) ) is significantly correlated with the symptoms of herniated disc disease. Among the different types of immune cells, macrophages are frequently noted in the herniated disc tissue. We undertook this study to clarify the interaction of the intervertebral disc (IVD) and macrophages with regard to the production of TNFα, IL-6, IL-8, and PGE(2) .

METHODS

We developed 2 animal models to assess the interactions of IVDs with macrophages in terms of TNFα, IL-6, IL-8, and PGE(2) production and pain-related behavior. We also cocultured IVDs and macrophages to assess the role of TNFα in IL-6, IL-8, and PGE(2) production.

RESULTS

IVD autografts induced TNFα, IL-6, IL-8, and cyclooxygenase 2 (COX-2) messenger RNA (mRNA) up-regulation; macrophage infiltration was seen shortly after the autograft was implanted. A significant decrease was noted in the mechanical threshold of the ipsilateral paw following the up-regulation of TNFα, IL-6, IL-8, and COX-2 mRNA. Only IVD and macrophage cocultures resulted in IL-8 and PGE(2) up-regulation. TNFα up-regulation was maximized before that of IL-6 and IL-8. TNFα neutralization attenuated production of IL-6 and PGE(2) , but not that of IL-8. Neutralization of TNFα and IL-8 significantly increased the paw withdrawal mechanical threshold in the IVD autograft and spinal nerve ligation model.

CONCLUSION

IVD-macrophage interaction plays a major role in sciatica and in the production of TNFα, IL-6, IL-8, and PGE(2) . TNFα is required for IL-6 and PGE(2) production, but not for IL-8 production, during IVD-macrophage interaction. Neutralization of TNFα and IL-8 can be a valuable therapy for herniated disc disease.

The impact of epidural steroid injections on the outcomes of patients treated for lumbar disc herniation: a subgroup analysis of the SPORT trial

BACKGROUND

The Spine Patient Outcomes Research Trial (SPORT) is a prospective, multicenter study of operative versus nonoperative treatment of lumbar intervertebral disc herniation. It has been suggested that epidural steroid injections may help improve patient outcomes and lower the rate of crossover to surgical treatment.

METHODS

One hundred and fifty-four patients included in the intervertebral disc herniation arm of the SPORT who had received an epidural steroid injection during the first three months of the study and no injection prior to the study (the ESI group) were compared with 453 patients who had not received an injection during the first three months of the study or prior to the study (the No-ESI group).

RESULTS

There was a significant difference in the preference for surgery between groups (19% in the ESI group compared with 56% in the No-ESI group, p < 0.001). There was no difference in primary or secondary outcome measures at four years between the groups. A higher percentage of patients changed from surgical to nonsurgical treatment in the ESI group (41% versus 12% in the No-ESI, p < 0.001).

CONCLUSIONS

Patients with lumbar disc herniation treated with epidural steroid injection had no improvement in short or long-term outcomes compared with patients who were not treated with epidural steroid injection. There was a higher prevalence of crossover to nonsurgical treatment among surgically assigned ESI-group patients, although this was confounded by the increased baseline desire to avoid surgery among patients in the ESI group. Given these data, we concluded that more studies are necessary to establish the value of epidural steroid injection for symptomatic lumbar intervertebral disc herniation.

Validity of the straight-leg raise test for patients with sciatic pain with or without lumbar pain using magnetic resonance imaging results as a reference standard

OBJECTIVE

The aim of this retrospective study was to assess validity of the straight-leg raise (SLR) test using magnetic resonance imaging (MRI) results as a reference standard in a group of patients with L4-L5 and L5-S1 lumbar-herniated disks and sciatic pain. The relationship between diagnostic accuracy of this test, age classes, and grade of lumbar disk displacement was investigated.

METHODS

The charts of 2352 patients with sciatic pain with/without lumbar pain were examined. Results of the SLR were then compared with previous spinal MRI. A 2 × 2 contingency table was created, and analysis of sensitivity, specificity, positive and negative predictive values, diagnostic odds ratio, likelihood ratio (LR), and receiver operating characteristic (ROC) curve was carried out. Homogeneous age classes were created to compare them statistically.

RESULTS

Magnetic resonance imaging findings showed lumbar disk herniation (LDH) in 1305 patients. Of these subjects, 741 were positive on SLR testing. Sensitivity was 0.36, whereas specificity was 0.74. Positive and negative predictive values were 0.69 and 0.52, respectively. Positive LR was 1.38, and negative LR was 0.87. Diagnostic odds ratio was 1.59, and ROC analysis showed an area under the curve (AUC) of 0.596. The AUC decreased from 0.730 in the 16- to 25-year subgroup to 0.515 in the 76- to 85-year subgroup. Similar results were obtained in subjects with LDH and nerve root compression.

CONCLUSIONS

Our results indicate low accuracy of the SLR in diagnosis of LDH if compared with MRI results. The discriminative power of the SLR seemed to decrease as age increased; thus, positive and negative results may be less conclusive in older patients.

A study of the relationship between type of lumbar disc herniation, straight leg raising test and peripheral T lymphocytes

OBJECTIVE

To observe changes in peripheral T lymphocytes of patients with lumbar disc herniation, and investigate the relationship between the type of herniation, signs and T lymphocyte subsets.

METHODS

Blood samples from 20 healthy blood donors (control group), and 49 patients (27 male and 22 female) with single-level lumbar intervertebral disc herniation were collected, the latter preoperatively. T lymphocytes subsets were detected by flow cytometer. According to the position of the intervertebral disc observed during surgery, the patients were divided into ruptured disc herniation (RDH) and degenerative disc herniation (DDH) groups. Straight leg raising (SLR) was assessed preoperatively.

RESULTS

Percentages of CD3+, CD4+, and ratio of CD4+/CD8+ in the RDH group were significantly higher, and of percentage of CD8+ significantly lower, than were those in the control group. Percentages of CD4+ and ratio of CD4+/CD8+ were significantly higher, and percentage of CD8+ significantly lower, in the positive SLR test group than were those in the negative SLR test group. The positive rate of SLR testing was significantly higher in the RDH than in the DDH group.

CONCLUSION

Our results suggest that changes in T lymphocyte subsets in peripheral blood take place after herniation of the lumbar intervertebral disc. T lymphocyte mediated immune responses may play an important role in the occurrence and development of signs in patients with herniated lumbar intervertebral discs. The SLR test may help to confirm that disc herniation has caused nerve root impairment by mechanical loading or inflammatory stimulus and provide guidance on the choice of treatment.

Conservatively treated massive prolapsed discs: a 7-year follow-up

INTRODUCTION

The natural history of a lumbar hernia of the nucleus pulposus (HNP) is not fully known and clear indications for operative intervention cannot be established from the literature. Several studies have shown that the largest discs appear to have the greatest tendency to resolve. The aim of this study was to investigate whether massive prolapsed discs can be safely managed conservatively once clinical improvement has occurred.

PATIENTS AND METHODS

Thirty-seven patients were studied by clinical assessments and serial magnetic resonance imaging (MRI) over 2 years. Patients had severe sciatica at first, but began to show clinical improvement despite the large disc herniations. Clinical assessment included the Lasegue test and neurological appraisal. The Oswestry Disability Index was used to measure function and changes in function. Serial MRI studies allowed measurement of volume changes of the herniated disc material over a period of time.

RESULTS

Initial follow-up at an average of 23.2 months revealed that 83% had a complete and sustained recovery at the initial follow-up. Only four patients required a discectomy. The average Oswestry disability index improved from 58% to 15%. Volumetric analysis of serial MRI scans found an average reduction of 64% in disc size. There was a poor correlation between clinical improvement and the extent of disc resolution.

CONCLUSIONS

A massive disc herniation can pursue a favourable clinical course. If early progress is shown, the long-term prognosis is very good and even massive disc herniations can be treated conservatively.

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.

Natural course of disc morphology in patients with sciatica: an MRI study using a standardized qualitative classification system

STUDY DESIGN

A prospective observational study of patients with sciatica.

OBJECTIVES

To describe the 14-month development of disc-related MRI findings in patients with sciatica receiving active conservative treatment.

SUMMARY OF BACKGROUND DATA

Previous studies of disc changes over time have reported reduction of herniations in 35% to 100% of cases. This wide range may be explained by differences in patient populations and classifications used to describe disc herniations.

METHODS

Data were obtained from patients with radicular pain (n = 181) who were randomly allocated into one of two active conservative treatment regimens lasting 8 weeks. All patients were scanned at baseline and at 14 months of follow-up. Variables of interest in the present study were disc contour and nerve root compromise at the presumed symptomatic disc level. Disc contour was assessed using the recommendations from the Combined Task Forces of NASS, ASSR, and ASNR.

RESULTS

In all, 154 patients were included in this study (70 women and 84 men; range, 18-65 years; mean and median age, 45 years). It was possible to identify the symptomatic disc level in 90% of patients. Extrusions or sequestrations were more common in individuals younger than 45 years and in men. Men were also more likely to have nerve root compromise. Only 3% of bulges and 38% of focal protrusions improved, whereas 75% to 100% of broad-based protrusions, extrusions, and sequestrations improved (P < 0.0001). Nerve root compromise improved in 21% to 80% depending on the disc contour. Neither type of treatment nor age had any effect on the development of MRI findings over time. However, nerve root compromise was more likely to improve in men.

CONCLUSIONS

This classification system could be used to identify the majority of symptomatic disc levels. At 14 months, the MRI outcome was generally good for disc herniations and nerve root compromise. Nerve root compromise had the best MRI prognosis if the disc was extruded at baseline. There were significant differences between men and women in relation to baseline findings as well as in relation to development of MRI findings over time.

Cytokine profiles in conditioned media from cultured human intervertebral disc tissue. Implications of their effect on bone marrow stem cell metabolism

BACKGROUND

Cytokines released from intervertebral discs cultured in vitro have not been profiled, and the effect of these cytokines on human bone marrow stem cells is yet to be studied.

MATERIALS AND METHODS

Intervertebral discs from 14 patients who had undergone spinal fusion surgery were cultured separately in vitro. Conditioned media were collected after 48 and 96 h of culture in serum-free Minimum Essential Medium (MEM). Profiling of the cytokines was conducted using pooled media. Conditioned medium from each patient was also tested in human bone marrow stem cell culture, and incorporation of alkaline phosphatase and 3H-thymidine incorporation was evaluated.

RESULTS

Of the 18 cytokines screened, 12 were found to be positive, but only eotaxin, IP-10, Rantes IL-6 and IL-8 seemed to be present at high levels. There was a close correlation between IL-6 and IL-8 levels in the medium (R = 0.90, p < 0.001). When the conditioned media were added to human bone marrow stem cell cultures, cellular proliferation was stimulated (p = 0.02), but alkaline phosphatase activity remained unchanged. Cellular proliferation correlated negatively with IL-6 levels (R = -0.44, p = 0.04).

INTERPRETATION

Intervertebral discs secrete certain cytokines into the medium when cultured in vitro, and conditioned media from cultured intervertebral discs stimulate proliferation of bone marrow stem cells.

Pathophysiology of inflammatory, degenerative, and compressive radiculopathies

In answering the patient's question regarding how treatments are likely to "help [her] herniated disc," the mechanical and chemical components of radiculopathy should be addressed. Focal disc abnormalities often can be observed in those without pain, and symptomatic discs can become asymptomatic. Disc lesions can resolve radiologically with time, and patients' symptoms can improve before their radiographs. The literature reviewed in this article suggests that the best opportunity to offer therapies that address the chemical component of injury might be in those patients with acute disc pathology. In the case of degenerative stenosis, gradually evolving mechanical stressors may comprise the primary component of injury. In other instances, patients with radiographic evidence of neural foraminal or lumbar central stenosis may become symptomatic secondary to a superimposed mechanochemical injury. Such stressors can include a focal disc protrusion, leaking nuclear material from an annular tear, or synovial fluid from an adjacent arthrotic zygapophyseal joint. In these patients, the successful treatment of the acute injury process might allow the affected neural elements to return to their state of accommodation in an environment of gradually evolving mechanical compromise. A growing body of literature has helped clinicians to better understand the mechanisms behind radicular disorders. As spine clinicians, we should strive to educate our patients so that they may become more knowledgeable consumers of spine care. As the components of radicular pathology are elucidated further, new biochemical therapies will likely evolve. Similarly, there will probably always be a subset of patients who will require mechanical decompression, and some of these individuals should be offered such treatment without delay. There may a time in the radicular injury process at which a window of opportunity for treatment begins to close. After this point, any therapy offered will not be as likely to result in a more complete symptomatic response. Patients with chronic radicular pain may have neural structural insults and an increased sensitivity of the somatosensory system. Clinicians should strive to avoid this end stage of neural injury, which is less reversible from a chemical or mechanical standpoint and may respond only to chronic pain management modalities.

Lumbosacral radiculopathies: conservative approaches to management

The prevalence of sciatica in Western society and its economic and functional impact make it an important problem to understand for treatment. Such understanding will impact greatly both medical management and decisions regarding activity, which could affect the perceived disability and financial dependence of a patient. This knowledge could be used to direct primary prevention, patient education, and future research efforts in back pain. The article also discusses that such strategies could improve health, decrease disability, and rein in costs.

Gadolinium diethylenetriaminepentaacetic acid enhancement in magnetic resonance imaging in relation to symptoms and signs among sciatic patients: a cross-sectional study

STUDY DESIGN

A cross-sectional descriptive study.

OBJECTIVES

Gadolinium enhancement in lumbar magnetic resonance imaging is not used routinely. The current study explored the possible intercorrelations of enhancement patterns with clinical symptoms and signs.

SUMMARY OF BACKGROUND DATA

Rim enhancement has been reported to occur in the periphery of disc herniations, and it is thought to represent neovascularization. To the authors' knowledge, the significance of the enhancement in relation to clinical symptoms has not been studied.

METHODS

Magnetic resonance imaging of the lumbar spine with intravenous gadolinium diethylenetriaminepentaacetic acid was performed in each patient. Various contrast enhancement parameters and volume of herniation were evaluated, and their correlations with clinical signs and symptoms (straight leg raising, motor defect, Achilles reflex, leg and back pain, disability) were analyzed.

RESULTS

The extent of rim enhancement correlated highly significantly with the degree of disc displacement, being most pronounced in the case of sequesters. The duration of sciatic symptoms correlated negatively with enhancement. The clinical symptoms did not correlate significantly with the different enhancement parameters or disc herniation volume. Straight leg raising correlated only slightly with the extent of rim enhancement (P = 0.04) when bulges were excluded. Achilles reflex abnormality correlated significantly with all enhancement parameters for lesions at L5-S1. In the final stepwise logistic regression model, contrast enhancement extent correlated most significantly with abnormal Achilles reflex (P = 0.0002).

CONCLUSIONS

Although rim enhancement of disc herniation is thought to represent a beneficial phagocytotic phenomenon, it may also have a harmful effect on the adjacent nerve root.

Comparison of the prevalence of inflammatory cells in subtypes of disc herniations and associations with straight leg raising

STUDY DESIGN

The prevalence of inflammatory cells in 205 disc herniations (DHs) and nine macroscopically normal discs for comparison was studied immunohistochemically. Inflammatory cells were separately analyzed in subtypes of DH. Immunohistochemical data were related to clinical parameters, the straight leg raising test (SLR) in particular.

OBJECTIVES

The objectives of the study were to compare the occurrence of inflammatory cells in various subtypes of DH and to determine the association between clinical data and inflammatory cell occurrence in a more extensive sample of DH, with separate analysis of DH subtypes.

SUMMARY OF BACKGROUND DATA

Previous studies have suggested a common occurrence of inflammation and inflammatory cells, particularly macrophages, in DHs. No studies on any larger material comprising different subtypes of DH have been done.

METHODS

For immunohistochemistry the alkaline phosphatase antialkaline phosphatase method was used. Monoclonal antibodies to T cells in general (CD2), activated T cells (CD25), B cells (CD22), and macrophages (CD68) were used. Obtained immunostaining results were then compared with clinical data, e.g., duration of pain, SLR, and type of DH (sequesters 86, extrusions 103, protrusions 16). Associations were studied by the chi2 test or Fisher's exact test, as applicable (level of significance P < 0.05).

RESULTS

Abundant T cells were seen in 17% of the 205 DHs, activated T cells in 17%, B cells in 16%, and macrophages in 37%. All cell types were 2-3 times more prevalent in sequestrated discs than in extrusions. In protrusions macrophages were abundantly seen in 25% (4 of 16) and no other inflammatory cells. In patients with positive SLR and a sequestrated disc abundant lymphocytes were seen three times more often than in extrusions. When patients with bilaterally negative SLR were compared with those with tight SLR (< or =30 degrees ) with respect to inflammatory cell occurrence, some significant differences were noted (CD68, P < 0.025; CD25, P = 0.04). A comparison between SLR bilaterally positive and bilaterally negative also showed associations for all four inflammatory cell types (P = 0.016 to P = 0.029). There was no correlation between inflammatory cells and duration of pain. Abundant inflammatory cells were never seen in control discs.

CONCLUSIONS

When SLR was positive and the DH type was sequestered, inflammatory cells were most commonly seen. Our results showed some statistically significant associations between inflammatory cells and SLR, most clearly when comparing bilaterally positive and negative SLR. Interestingly, a bilaterally positive SLR showed an association with all four inflammatory cell types analyzed. Tight SLR also showed an association, particularly with macrophages. In addition to tissue resorption, they may participate in sciatic pain. Even though lymphocytes were less prevalent, they may have some role in sequestered discs and bilaterally positive SLR.