Genetic influences on cervical and lumbar disc degeneration: a magnetic resonance imaging study in twins.
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OBJECTIVE: Degenerative intervertebral disc disease is common; however, the importance of genetic factors is unknown. This study sought to determine the extent of genetic influences on disc degeneration by classic twin study methods using magnetic resonance imaging (MRI). METHODS: We compared MRI features of degenerative disc disease in the cervical and lumbar spine of 172 monozygotic and 154 dizygotic twins (mean age 51.7 and 54.4, respectively) who were unselected for back pain or disc disease. An overall score for disc degeneration was calculated as the sum of the grades for disc height, bulge, osteophytosis, and signal intensity at each level. A "severe disease" score (excluding minor grades) and an "extent of disease" score (number of levels affected) were also calculated. RESULTS: For the overall score, heritability was 74% (95% confidence interval [95% CI] 64-81%) at the lumbar spine and 73% (95% CI 64-80%) at the cervical spine. For "severe disease," heritability was 64% and 79% at the lumbar and cervical spine, respectively, and for "extent of disease," heritability was 63% and 63%, respectively. These results were adjusted for age, weight, height, smoking, occupational manual work, and exercise. Examination of individual features revealed that disc height and bulge were highly heritable at both sites, and osteophytes were heritable in the lumbar spine. CONCLUSION: These results suggest an important genetic influence on variation in intervertebral disc degeneration. However, variation in disc signal is largely influenced by environmental factors shared by twins. The use of MRI scans to determine the phenotype in family and population studies should allow a better understanding of disease mechanisms and the identification of the genes involved. (+info)
Clinical evaluation and treatment options for herniated lumbar disc.
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Degeneration of the intervertebral disc from a combination of factors can result in herniation, particularly at the L4-5 and L5-S1 levels. The presence of pain, radiculopathy and other symptoms depends on the site and degree of herniation. A detailed history and careful physical examination, supplemented if necessary by magnetic resonance imaging, can differentiate a herniated lumbar disc from low back strain and other possible causes of similar symptoms. Most patients recover within four weeks of symptom onset. Many treatment modalities have been suggested for lumbar disc herniation, but studies often provide conflicting results. Initial screening for serious pathology and monitoring for the development of significant complications (such as neurologic defects, cauda equina syndrome or refractory pain) are essential in the management of lumbar disc herniation. (+info)
Multiple disc herniations in spondyloepiphyseal dysplasia tarda. A case report.
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Spondyloepiphyseal dysplasia (SED) tarda is a group of inherited dysplasias in which the spine and the epiphyses of long bones are affected from late childhood. A 19-year-old male was diagnosed as SED tarda. He had a thoracic and then lumbar disc herniations which were separated by a 4-year interval. Surgical excision was performed for each disc herniation. This is the first case report of multiple disc herniations in SED. (+info)
Extradural inflammation associated with annular tears: demonstration with gadolinium-enhanced lumbar spine MRI.
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Annular tears are manifest on MRI as the high-intensity zone (HIZ) or as annular enhancement. Patients with annular tears may experience low back pain with radiation into the lower limb in the absence of nerve root compression. Inflammation of nerve roots from leak of degenerative nuclear material through full-thickness annular tears is a proposed mechanism for such leg pain. The aim of this study is to illustrate the appearance of extradural enhancement adjacent to annular tears in patients being investigated for low back pain with radiation into the lower limb(s). Sagittal T1- and T2-weighted spin echo and axial T1-weighted spin echo sequences were obtained in eight patients being investigated for low back and leg pain. In all patients, the T1-weighted sequences were repeated following intravenous gadopentetate dimeglumine (Gd-DTPA). Annular tears were identified at 12 sites in eight patients. Extradural inflammation appeared as a region of intermediate signal intensity replacing the fat between the posterior disc margin and the theca, which enhanced following Gd-DTPA. The inflammatory change was always associated with an annular tear, and in four cases directly involved the nerve root. Enhancement of the nerve root was seen in two cases. The findings may be relevant in the diagnosis of chemical radiculopathy secondary to inflammation at the site of an annular leak from a degenerating disc. (+info)
Ten- to 15-year outcome of surgery for lumbar disc herniation: radiographic instability and clinical findings.
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The most appropriate treatment for radiculopathy associated with disc pathology is still controversial. Since 1934, surgical treatment has consisted of hemilaminectomy and removal of the herniated material. Many authors believe that these procedures may cause degenerative spondylosis and vertebral instability. Several surgical methods have been proposed, but the long-term effects are still being debated. In addition there appear to be few well-designed outcome studies on the management of this disease. In the present study, 150 patients were selected for surgery with strict criteria and all treated with the standard technique. The series was evaluated by subjective analyses (Roland questionnaire; 120 patients), objective examinations (68 patients - 56.6%) and radiographic studies including dynamic views (analyzed by the Taillard and Boxall methods) to establish the presence of vertebral instability (50 patients - 41.6%). The subjective and objective analyses showed a high rate of good results. Radiographic studies showed vertebral instability in 30 cases, but only 9 were symptomatic. Recurrences were not observed and only a few patients suffered from leg pain. The standard procedure for lumbar disc herniation showed good results at 10- and 15-year follow-up. (+info)
The assessment of appropriate indications for laminectomy.
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We have developed criteria to determine the appropriate indications for lumbar laminectomy, using the standard procedure developed at the RAND corporation and the University of California at Los Angeles (RAND-UCLA). A panel of five surgeons and four physicians individually assessed 1000 hypothetical cases of sciatica, back pain only, symptoms of spinal stenosis, spondylolisthesis, miscellaneous indications or the need for repeat laminectomy. For the first round each member of the panel used a scale ranging from 1 (extremely inappropriate) to 9 (extremely appropriate). After discussion and condensation of the results into three categories laminectomy was considered appropriate in 11% of the 1000 theoretical scenarios, equivocal in 26% and inappropriate in 63%. There was some variation between the six categories of malalignment, but full agreement in 64% of the hypothetical cases. We applied these criteria retrospectively to the records of 196 patients who had had surgical treatment for herniated discs in one Swiss University hospital. We found that 48% of the operations were for appropriate indications, 29% for equivocal reasons and that 23% were inappropriate. The RAND-UCLA method is a feasible, useful and coherent approach to the study of the indications for laminectomy and related procedures, providing a number of important insights. Our conclusions now require validation by carefully designed prospective clinical trials, such as those which are used for new medical techniques. (+info)
Delayed vertebral slip and adjacent disc degeneration with an isthmic defect of the fifth lumbar vertebra.
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We reviewed the radiographs of 325 unselected patients with defects in the pars interarticularis of L5 to study whether the incidence of vertebral slip in spondylolysis of L5 remained unchanged after the age of 20 years. MRI was also carried out on 111 of the patients to investigate the relationship between the shape of the transverse process of L5 and the degeneration of the discs adjacent to this level. The incidence of spondylolisthesis increased with age from 17% in the second decade to 51% in the sixth. The transverse process was significantly more slender in patients with less degeneration at L4/5 and advanced degeneration at L5/S1 than in patients with advanced degeneration at L4/5 and less degeneration at L5/S1. Vertebral slip secondary to an isthmic defect of L5 after the age of 20 years was confirmed and the adjacent disc degeneration was significantly related to the vertical thickness of the transverse process of L5. (+info)
Kinetics of tissue and serum matrix metalloproteinase-3 and tissue inhibitor of metalloproteinases-1 in intervertebral disc degeneration and disc herniation.
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We have evaluated the correlation between disc herniation or degeneration and the levels of matrix metalloproteinase-3 (MMP-3) or tissue inhibitor of metalloproteinases-1 (TIMP-1). The lumbar discs obtained from 22 autopsied cadavers and 21 patients with lumbar disc herniation were examined. Immunohistochemical study: The number of MMP-3-producing and TIMP-1-producing cells increased as disc herniation or degeneration progressed. Zymography: Activated type MMP-3 was observed in the normal and herniated intervertebral disc excluding the intervertebral disc with protrusion-type herniation. RT-PCR: The MMP-3 gene was expressed in all groups. However, the expression of the TIMP-1 gene was weak in the normal group as well as in the protrusion type disc herniation. Determination of tissue and serum levels of MMP-3 and TIMP-1 was increased as disc degeneration or herniation progressed. There were positive correlations between the number of MMP-3-producing or TIMP-1-producing cells in the intervertebral disc and the tissue or serum levels of MMP-3 and TIMP-1. These results suggested that MMP-3 and TIMP-1 were closely related to the progression of disc degeneration or herniation. The results also suggested that MMP-3 and TIMP-1 exhibited similar kinetics. Moreover, the serum levels of MMP-3 and TIMP-1 reflected the progression of disc degeneration and herniation. (+info)