Matrix metalloproteinase-7-dependent release of tumor necrosis factor-alpha in a model of herniated disc resorption.
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Herniated disc (HD), one of the major causes of low back pain, is often resolved spontaneously without surgical intervention. Resorption is associated with a marked increase in infiltrating macrophages, and the matrix metalloproteinases (MMP) MMP-3 and MMP-7 have been implicated in this phenomenon. We developed a murine organ culture model in which intact intervertebral discs were cocultured with peritoneal macrophages to investigate the role of MMPs in HD resorption. Using macrophages isolated from MMP-null mice, we report that macrophage-produced MMP-7 was required for proteoglycan degradation, loss of wet weight, and macrophage infiltration of cocultured discs. The inability of MMP-7-deficient macrophages to infiltrate discs could not be attributed to a defect in macrophage migration. MMP-7 was required for the release of the cytokine TNF-alpha from peritoneal macrophages. The generation of soluble TNF-alpha was essential for the induction of MMP-3 in disc cocultures, which in turn is required for the generation of a macrophage chemoattractant and subsequent macrophage infiltration. TNF-alpha release from macrophages was necessary but insufficient for disc resorption, which required macrophage infiltration. We conclude that there is extensive communication between macrophages and chondrocytes in HD resorption and that an essential component of this communication is the requirement for MMPs to release soluble bioactive factors. (+info)
Why the back of the child?
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An international congress about "the back of children and teenagers and the prevention of backache" was held in March 1999 in Grenoble (France). Beside specific low back pain following progressive and growth diseases, special attention was paid to non-specific low back pain (LBP). Some epidemiological data show a high incidence of LBP during and after the rapid growth phase, with the concomitant possibility of continued or recurrent evolution. MRI studies reveal frequent signs of disc degeneration: they start after the growth phase, spread during adolescence and are often correlated with backache. An immunohistological study seems to confirm the presence of degenerative-type alterations and changes in collagen in the vertebral plates and nucleus of juvenile spine. These data must be confirmed, and their relation to natural history and prognosis of juvenile LBP have to be clarified by longitudinal studies. (+info)
Non-specific low back pain in children and adolescents: risk factors.
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Low back pain (LBP) among children and adolescents has become the subject of an increasing amount of literature over the last 15 years. This topic, which was considered almost insignificant less than two decades ago, was the focus of a recent international meeting organised in Grenoble (France) in March 1999. This review paper is the result of an literature update search performed by members of three groups which have been active in this field for many years. Current epidemiological data on LBP is summarized as well as the role of the major risk factors according to studies published in the principal peer reviewed journals interested in the topic. (+info)
Low back pain in a population of school children.
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A study was undertaken to analyse the prevalence of low back pain (LBP) and confounding factors in primary school children in the city of Antwerp. A total of 392 children aged 9 were included in the study. All children completed a validated three-page questionnaire and they all underwent a specific lumbar spine oriented medical examination during their annual routine medical school control. This examination was performed by the city school doctors. The questionnaire was composed of easy "yes/no" questions and visual analogue scales. Statistical analysis was performed using Student's t-test and chi-squared test at the significance level P < 0.05. The prevalence of LBP was high. No gender difference was found. A total of 142 children (36%) reported having suffered at least one episode of LBP in their lives. Of these, 33 (23%) had sought medical help for LBP from a doctor or physiotherapist. Sixty-four percent of children reporting LBP said that at least one of their parents suffered from or complained of LBP. This was significantly higher than for the children who did not report having suffered LBP. The way in which the school satchel was carried (in the hand, on the back) had no bearing on the incidence of LBP. There was significantly more LBP in children who reported playing video games for more than 2 h per day, but this was not so for television watchers. The visual analogue scales concerning general well-being were all very significantly correlated with self-reported LBP, with children who reported LBP being more tired, less happy, and worse sleepers. Of the 19 clinical parameters taken down during the medical examination, only one was significantly more prevalent in the group of children reporting LBP: pain on palpation at the insertion site on the iliac crest of the ilio-lumbar ligament. From this study we can establish that there are few clinical signs that can help to single out school children with LBP. (+info)
Recurrent pain after lumbar discectomy: the diagnostic value of peridural scar on MRI.
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The association between peridural scarring and recurrent pain after lumbar discectomy is much debated. A recently published study found that patients with extensive peridural fibrosis were 3.2 times more likely to experience recurrent radicular pain than those with less extensive scarring. This finding may lead to an overestimation of peridural fibrosis in clinical practice. In a retrospective study we analyzed the records of 53 patients who underwent a lumbar MRI because of recurrent pain after first unilateral microdiscectomy. Patients were classified as those with radicular or non-radicular pain according to history and clinical findings. The diagnosis was confirmed by spinal anesthetic block. The extension of scarring was compared between the two groups of patients. The amount of epidural fibrosis was examined on contrast-enhanced MRI in axial slices subdivided into four quadrants. The amount of fibrosis was divided into four stages in each affected quadrant. We found no differences regarding the amount of peridural fibrosis between patients with radicular pain and patients with non-radicular pain. We conclude that the extent of peridural scarring as defined by MRI is of minor value in the differential diagnosis of recurrent back and leg pain after lumbar microdiscectomy. (+info)
Cervical diskography: analysis of provoked responses at C2-C3, C3-C4, and C4-C5.
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BACKGROUND AND PURPOSE: Previous authors have described the locations of provoked responses to cervical diskography from C3-C4 to C6-C7, but we have found no description of the findings at C2-C3. This study was undertaken to analyze the sensations provoked during cervical diskography at C2-C3 and to compare the results with those provoked at C3-C4 and C4-C5. METHODS: The locations of diskographically provoked responses from 40 consecutive patients who had undergone C2-C3, C3-C4, and C4-C5 diskography were analyzed. Only intensely painful (> or = 7/10) and concordant responses were considered. Disk morphology on MR images and diskograms was also compared with the provoked responses. RESULTS: Eighteen subjects described either unilateral (n = 10) or bilateral (usually asymmetric) (n = 8) concordant pain at the craniovertebral junction in response to C2-C3 diskography. Nine subjects described either unilateral (n = 5) or bilateral (n = 4) neck pain during injection. Cephalalgia or head pain was provoked in 19 subjects, seven bilaterally. Four subjects described either unilateral (n = 3) or bilateral (n = 1) trapezius muscle and/or shoulder pain. Preliminary MR studies were not helpful, as most C2-C3 disks either appeared normal or exhibited nonspecific signs of degeneration. All disks exhibited either fissuring or extradiskal leakage of contrast material at diskography, regardless of the response provoked. CONCLUSION: Diskography at C2-C3 and C3-C4 frequently produces pain sensations in the head, craniovertebral junction, and neck. There is no correlation between C2-C3 disk morphology and the diskographically provoked response. (+info)
Relationship of Schmorl's nodes to vertebral body endplate fractures and acute endplate disk extrusions.
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BACKGROUND AND PURPOSE: Literature regarding clinical pain syndromes associated with acute, traumatic Schmorl's nodes (SNs) is limited. Our purpose was to determine whether an SN could be related to a previous traumatic event producing either acute SN or a vertebral endplate fracture. METHODS: Two neuroradiologists independently reviewed initial and follow-up MR examinations of 14 patients with a clinical diagnosis of acute, symptomatic thoracolumbar SNs or vertebral body endplate fractures that evolved into SNs to evaluate marrow edema, signal intensity, margin definition, presence of intravertebral extruded disk material, and pattern of contrast enhancement. RESULTS: Edema of the affected vertebral body, adjacent to an endplate without wedging or collapse, was observed on the initial MR images in all cases. The initial MR images of six (43%) of 14 patients exhibited only edema of the marrow immediately adjacent to the endplate without wedging or collapse. The MR images obtained at the time of follow-up showed subsequent formation of a chronic and eventually asymptomatic SN for all six patients. The initial MR images of eight (57%) of the 14 patients showed the typical appearance of acute SNs with marrow edema of the affected vertebra. The contrast-enhanced images of three patients manifested enhancement of the invaginated disk material in three (100%) of three cases and enhancement of the surrounding vertebral body in one case (33%). Six (43%) of 14 patients had acute typical compression fracture of a vertebral body of at least one additional level. CONCLUSION: Most (57%) of the SNs in this series could be traced to episodes of significant, sudden-onset, localized, nonradiating back pain and tenderness for which the MR images showed SNs surrounded by vertebral body marrow edema. The remaining SNs (43%) were not immediately apparent as SNs and manifested only as vertebral body edema representing endplate fracture but did evolve into classical chronic SNs that follow-up imaging revealed. (+info)
Lumbar disc high-intensity zone: the value and significance of provocative discography in the determination of the discogenic pain source.
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Disagreement still exists in the literature as to the significance of the high-intensity zone (HIZ) demonstrated on magnetic resonance imaging (MRI) as a potential pain indicator in patients with low back pain. A prospective blind study was therefore conducted to evaluate the lumbar disc high-intensity zone with the pain provocation response of lumbar discography. Consecutive patients with low back pain unresponsive to conservative treatment and being considered for spinal fusion were subjected to MRI followed by lumbar discography as a pre-operative assessment. The discographer was blinded to the results of the MRI scans. We used the chi-squared test to analyse our results. Ninety-two HIZs were identified in 73 patients, mainly occurring at L4/5 (48%) and L5/S1 (35%). Significant correlation was found between abnormal disc morphology and the HIZ (P < 0.001). In morphologically abnormal discs (grades 3, 4 and 5), there was a significant correlation between the HIZ and exact or similar pain reproduction (P < 0.001). The sensitivity, specificity and positive predictive value for pain reproduction were high, at 81%, 79% and 87% respectively. The nature of the HIZ remains unknown, but it may represent an area of secondary inflammation as a result of an annular tear. We conclude from our study that the lumbar disc HIZ observed on MRI in patients with low back pain is likely to represent painful internal disc disruption. (+info)