Characterization of cultured human ligamentum flavum cells in lumbar spine stenosis.

To investigate the pathogenesis of the degenerative changes of the ligamentum flavum occurring in lumbar spine stenosis, yellow ligament cells from patients with lumbar spine stenosis were cultured for the first time and subjected to biochemical, histochemical and immunohistochemical study. Stenotic ligamentum flavum (SLF) cells were seen to express high levels of alkaline phosphatase (ALP) activity and to produce a matrix rich in type I and III collagen, fibronectin and osteonectin. The matrix mineralized only following beta-glycerophosphate (betaGP) and ascorbic acid supplementation. Stimulation with human parathyroid hormone (PTH) increased intracellular cAMP concentration. These findings indicate that there was significant evidence of osteoblast-like activity in these cells. SLF cells also stained for S100 protein, type II and type X collagen, and co-localized type II collagen and ALP labelling, reflecting the presence of hypertrophic chondrocyte-like cells. Cultures from control patients showed neither osteoblastic nor chondrocytic features: they expressed type I and type III collagen and fibronectin, but did not stain for osteonectin, nor were bone-like calcifications observed in presence or absence of betaGP. Normal ligamentum flavum (NLF) cells did not synthesized S100 protein or type II or type X collagen, and showed a weaker response to PTH stimulation. Our data demonstrated the presence of hypertrophic chondrocytes with an osteoblast-like activity in the ligamentum flavum of patients with spinal stenosis suggesting that they could have a role in the pathophysiology of the heterotopic ossification of ligamentum flavum (OLF) in lumbar spine stenosis.     

高氟摄入致家兔胸椎黄韧带退变的实验研究

目的　探讨引起黄韧带退变的病因和机理 ,研究慢性氟中毒与黄韧带退变的关系。方法　将氟化钠注入家兔皮下 ,使其发生氟中毒 ,观察高剂量氟摄入对家兔黄韧带组织结构的影响。结果　高氟摄入后 ,家兔胸椎黄韧带组织内弹力纤维减少、断裂。胶原纤维大量增生 ,排列不规则。在电镜下 ,可见钙盐结晶在增生的胶原纤维间沉着。结论　高氟摄入可以引起黄韧带的退变与钙化。提示低氟摄入 ,可能具有预防和减少黄韧带退变的作用。     

Calcification of the cervical ligamentum flavum--case report

A 52-year-old male presented with calcification of the cervical ligamentum flavum manifesting as hypesthesia of the bilateral middle, ring, and little fingers and ulnar halves of both forearms, as well as motor weakness in the bilateral upper extremities and gait disturbance. Cervical x-ray tomography detected a round calcified mass on the posterior wall of the cervical canal at the C-5 level. Computed tomography showed the round, nodular calcified mass more clearly. Magnetic resonance imaging showed an epidural low intensity mass compressing and distorting the cervical cord at the C-5 level on both T1- and T2-weighted images. Administration of gadolinium-diethylenetriaminepenta-acetic acid caused marginal enhancement of the mass. The lesion was eventually removed by posterior laminectomy. The mass was composed of a very hard crystal-like calcified deposition in the ligamentum flavum. X-ray diffraction analysis of the histological specimen showed calcium pyrophosphate dihydrate (CPPD) and hydroxyapatite in the crystal-like substance, confirming that CPPD is responsible for calcification of the cervical ligamentum flavum.     

Calcium pyrophosphate dihydrate crystal deposition disease in the cervical ligamentum flavum

The authors describe three cases of cervical radiculomyelopathy caused by calcium pyrophosphate dihydrate crystal deposition disease (CPPDcdd). Radiological investigations revealed nodular calcifications, 5 to 7 mm in diameter, in the cervical ligamentum flavum compressing the spinal cord. Light microscopic, scanning electron microscopic, and x-ray diffraction studies were performed on all three surgical specimens obtained by laminectomy. In two of the cases x-ray microanalysis and transmission electron microscope studies were also performed. This study defined the presence of two patterns of crystal deposition in the ligamentum flavum. One is a nodular deposit, in which hydroxyapatite crystals are seen in the central part of the nodules, with calcium pyrophosphate dihydrate (CPPD) being distributed thinly around them. The other pattern is a linear deposit seen in multiple ligaments and composed of pure CPPD, which causes minimal thickening of the ligaments. A transitional pattern between the two types was also observed. This study revealed details of the nodular deposition of crystals in the ligamentum flavum and demonstrates that CPPDcdd and so-called "calcification of the ligamentum flavum" are the same disease: namely, CPPDcdd. Hydroxyapatite is assumed to have been transformed from CPPD.     

腰椎管狭窄症的影像学诊断

目的：探讨腰椎管狭窄症的X线、CT及MRI诊断价值。方法：分析130例临床诊断和影像学检查征象典型的腰椎管狭窄症的病例资料。男83例,女47例;年龄27～75岁,平均43.5岁。所有病例均行CT检查,其中23例行X线检查,57例行MRI扫描。结果：腰椎管狭窄位于L3,4水平25例,L4,5水平48例,L5S1水平57例。CT显示椎体后缘、椎板、下关节突骨质增生46例,椎板上下关节突肥大7例,黄韧带钙化、骨化13例,椎体向前滑脱5例,侧隐窝狭窄24例,椎间孔狭窄35例。MRI显示椎间盘突出伴黄韧带肥厚23例,黄韧带对称性肥厚18例,广泛多节段增生肥厚9例,局限性黄韧带肥厚7例。结论：继发性腰椎管狭窄症的最常见原因是退变。传统X线检查有很大的局限性,CT和MRI具有多方位成像和分辨率高的优点,但在韧带骨化上MRI难于显示,而CT能很好的显示韧带钙化与骨化及骨质改变,腰椎管狭窄症检查应该首选CT。     

Histology of the ligamentum flavum in patients with degenerative lumbar spinal stenosis

The degree of calcification as well as the structural changes of the elastic fibres in the ligamentum flavum in patients with degenerative lumbar spinal stenosis were evaluated and the results were compared to those of patients without spinal stenosis. In 21 patients (13 male, 8 female) with lumbar spinal stenosis the ligamentum flavum was removed, histologically processed and stained. The calcification, the elastic/collagenous fibre ratio as well as the configuration of the fibres were evaluated with an image analyzing computer. As a control group, 20 ligaments of 10 human corpses were processed in the same way. The results were statistically analysed using the Mann-Whitney-Wilcoxon test (α = 0.05) and the t-test (α = 0.05). Nearly all the ligaments of patients with lumbar spinal stenosis were calcified (average 0.17%, maximum 3.8%) and showed relevant fibrosis with decreased elastic/collagenous fibre ratio. There was a significant correlation between age and histological changes (P < 0.05). In the control group we only found minimal calcification in 3 of 20 segments (average 0.015%). No relevant fibrosis was found and the configuration of elastic fibres showed no pathologic changes. The results of this study illustrate the important role of histological changes of the ligamentum flavum for the aetiology of lumbar spinal stenosis. Received: 31 July 1998 Revised: 19 March 1999 Accepted: 12 April 1999     

退行性变黄韧带细胞的体外培养及初步鉴定

目的：探讨黄韧带退变的发生机理。方法：采用组织块培养法，体外培养正常黄韧带和退变性黄韧带细胞．并进行细胞化学、免疫细胞化学等方面研究。结果：黄韧带细胞可以在体外增殖和传代，退变性黄韧带细胞呈现出某些成骨细胞表型特征，而正常黄韧带细胞主要为成纤维细胞表型。结论：退变黄韧带中存在大量具备某些成骨细胞表型特征的细胞，其中包括软骨细胞，它们可能被骨形成蛋白等骨生长因子所调控。     

Ultrastructural study of calcification process in the ligamentum flavum of the cervical spine

The ultrastructure of the formation of calcified nodules in three cases of symptomatic calcification of the cervical ligamentum flavum were studied. In some areas of the ligament, extracellular plasma membrane-invested matrix vesicles and thick wall-bound matrix giant bodies with or without mineralized deposits were present. These calcified vesicles and bodies were also encountered in the wide mineralized areas among the collagen and elastic fibers in the ligament. The mineralization process of the calcified nodules in the ligamentum flavum implies that matrix vesicles and matrix giant bodies acquire mineralized precipitates; then some gather in clusters. Calcified deposits may spread to collagen and elastic fibers contiguous with the calcified vesicles and bodies, and some eventually coalesce to make a calcified nodule.     

A macromolecular inhibitor of in vitro calcification of tendon matrix

Summary Bovine and human tendon tissue do not induce calcification in vitro. However, extraction of those tissues with 3% Na₂HPO₄ converts them to calcifiable matrices. The supernatant fraction derived from the extraction contains a nondialyzable, perchloric acid soluble component that inhibits calcification of the extracted matrix. This inhibitory substance is characterized by a molecular weight in the range of 85,000–100,000. Exposure to pronase or hyaluronidase did not alter the inhibitory potency but did render the inhibitor dialyzable. Commercial sources of hyaluronic acid, chondroitin-6-sulfate, chrondroitin-4-sulfate, dermatan sulfate, heparin and lysozyme did not inhibit calcification of the extracted matrix. Phosvitin, a phosphoglycoprotein is a potent inhibitor. Although phosvitin and the tendon extract also inhibit calcification of previously calcified matrix, they have no detectable effect on the rate of decalcification. We conclude that the mechanism of inhibition is characterized by a degree of specificity and that phosvitin and a macromolecular component of tendon tissue blocks conversion of an intermediate matrix-bound CaP complex to crystalline apatite. It seems reasonable that the tendon inhibitor could function in situ and possibly in vivo to control calcification of tendon tissue.     

Thoracic myelopathy caused by calcified ligamentum flavum

Calcification of the ligamentum flavum is a rare manifestation of the calcium pyrophosphate dihydrate deposition disease (CPPD). In CPPD deposition disease, spinal involvement is rare. Until now, thoracic spine CPPD causing thoracic cord compression has been reported in only sporadic cases. We report a new case of thoracic calcification of the ligamentum flavum. In our case, similar to the other reported cases, an affected middle-aged woman despite the clinical and MRI signs of myelopathy had an unexpected important and rapid improvement of the neurological picture. This condition should be considered in differential diagnosis of thoracic cord compression to offer the patient an early and useful surgical treatment.     

Calcification of the cervical ligamentum flavum. Case report and review of the literature

Calcification of the cervical ligamentum flavum is a rare entity observed exclusively in Japanese people. We report a new case in a 65-year-old man from Tunisia who presented with symptoms of cervical myelopathy with mild tetra paresis, sensory abnormalities and dysuria. Magnetic resonance imaging (MRI) showed a posterior compression of the spinal cord at C3-C4. CT-scan showed a calcification of the ligamentum flavum at level C3-C4, compressing the left postero-lateral aspect of the spinal cord. C3-C4 laminectomy was performed with removal of abnormal ligamentum flavum tissue. The postoperative course was uneventful and all symptoms resolved. Calcification of the cervical ligamentum flavum is a rare entity; the diagnosis is easy but the pathogenesis remains unclear. Literature regarding this pathology is reviewed.     

A case of myelopathy caused by calcified nodules of cervical ligamentum flavum

A case is reported of a 71-year-old female with cervical myelopathy caused by calcified nodules in the cervical ligamentum flavum and improved by en bloc laminectomy. The calcified nodules were formed by the deposition of two crystals, hydroxyapatite (HAP) and calcium pyrophosphate dihydrate (CPPD). Light microscopy, scanning electron microscopy, energy dispersive X-ray microanalysis and X-ray diffraction study disclosed that the larger nodule located on the right was composed mainly of HAP in the central part and CPPD in the circumference. On the other hand, the smaller nodule located on the left was composed mainly of CPPD crystal. These findings support the hypothesis that calcification of the ligamentum flavum and CPPD crystal deposition disease in the cervical region are the same entity and the both are merely different aspects of the same entity at different chronological stages.     

Hypertrophy of ligamentum flavum in lumbar spinal stenosis associated with increased proteinase inhibitor concentration

BACKGROUND: It is well known that age-related fibrosis, or decreases in the elastin-to-collagen ratio of the ligamentum flavum, along with hypertrophy of the ligamentum flavum, are associated with lumbar spinal stenosis. However, the molecular mechanism by which this fibrosis and hypertrophy develop is unknown. Tissue inhibitors of matrix metalloproteinase (TIMPs) are proteinase inhibitors that suppress extracellular matrix degradation. Elevated TIMP-1 and TIMP-2 expression has been implicated in various fibrotic diseases of the liver, kidney, lung, and heart. These TIMPs can also induce cellular proliferation and inhibit apoptosis in a wide range of cell types. These findings led us to postulate that TIMP-1 and TIMP-2 might also be associated with hypertrophy and fibrosis of the ligamentum flavum in lumbar spinal stenosis. METHODS: We quantified and localized TIMP expression in ligamentum flavum tissues that had been obtained during surgery from thirty patients with spinal stenosis and from thirty gender-matched control patients with disc herniation. The thickness of the ligamentum flavum at the level of the facet joint was measured on axial T1-weighted magnetic resonance images. In addition, we examined ligamentum flavum tissues for the expression of markers of cellular proliferation and apoptosis. RESULTS: The ligamentum flavum was significantly thicker in the patients with spinal stenosis (mean, 5.68 mm) than in the patients with disc herniation (mean, 2.70 mm) (p < 0.001). The concentration of TIMP-2 in the ligamentum flavum was significantly higher in the patients with spinal stenosis (mean, 12.62 ng/mL) than in those with disc herniation (mean, 8.85 ng/mL) (p = 0.028). TIMP-1 and TIMP-2 were detected in the cytoplasm of ligamentum flavum fibroblasts. TIMP-1 and TIMP-2 concentrations were associated with hypertrophy of the ligamentum flavum (p = 0.015 and p = 0.003, respectively). None of the samples from the patients with stenosis had evidence of proliferation of ligamentum flavum fibroblasts. The expression of markers for apoptosis was significantly higher in the patients with spinal stenosis (58.8%) than in those with disc herniation (26.6%) (p < 0.001). CONCLUSIONS: Increased TIMP expression has been implicated in fibrosis and hypertrophy of the extracellular matrix of several organs. Our results suggest that increased expression of TIMP-2 in ligamentum flavum fibroblasts is associated with fibrosis and hypertrophy of the ligamentum flavum in patients with spinal stenosis.     

Cervical myelopathy due to calcification of the ligamentum flavum

An elderly Caucasian woman presented with a cervical myelopathy due to cervical spinal cord compression posteriorly by calcified ligamentum flavum and anteriorly by cervical osteophytic bars. Although recognized in the Japanese population, calcification of the ligamentum flavum as a cause of cervical myelopathy is very rare in Caucasians, with only one case previously reported.     

Hypertrophied ligamentum flavum in lumbar spinal canal stenosis. Pathogenesis and morphologic and immunohistochemical observation.

To investigate the pathogenesis of hypertrophy of the ligamentum flavum, 45 cases of lumbar canal stenosis were evaluated by computed tomography scan and pathologic and immunohistochemical studies. The ligamentum flavum along with the medial one-third of the superior facet was obtained en bloc to include the enthesis. Statistically significant differences in transverse area and thickness of the ligamentum flavum were evident compared to the control group (P < 0.01). Pathogenesis of the hypertrophied ligamentum flavum was classified into three major groups: 1) fibrocartilage change due to proliferation of type II collagen, 2) ossification, and 3) calcium crystal deposition. It is stressed that marked proliferation of Type II collagen from the enthesis to the ligament side was revealed in the capsular portion of the hypertrophied ligament.     

Anatomical analysis of the human ligamentum flavum in the thoracic spine: Clinical implications for posterior thoracic spinal surgery

Background

Knowledge of the ligamentum flavum anatomy is important for posterior spinal surgery. However, only a few studies have evaluated the relationship between the thoracic ligamentum flavum and its surrounding structures. This study aimed to clarify the anatomy of the thoracic ligamentum flavum.

Untreated hypophosphatemic vitamin D-resistant rickets with symptomatic ossification of the ligamentum flavum.

An adult case of untreated hypophosphatemic vitamin D-resistant rickets with symptomatic ossification of the ligamentum flavum in the thoracic region is reported and discussed with regard to the calcium metabolism and the ligamentous ossification. Factors influencing ossification of the ligamentum flavum may be mechanical stress on the spine and an increase in calcium retention.     

Calcification des ligaments jaunes du rachis cervical chez l’antillais

Objective. Calcification of the ligamentum flavum at the cervical spine is an uncommon condition reported mainly in Japanese patients. We describe the clinical manifestations, imaging study findings, and outcomes in six cases seen in the French West Indies. Patients and methods. We retrospectively reviewed the medical charts of six patients admitted to an orthopedics department for spinal cord compression shown upon computed tomography to be caused by calcification of the ligamentum flavum. There were five women and one man, mean age at admission was 71.7 years (range, 64-79 years), and all six patients were black. Results. Five patients had cervical myelopathy and one was asymptomatic. All five symptomatic patients had cervical spinal stenosis, explaining the rapid symptom onset (within six and a half months) and severe motor loss. Computed tomography reconstruction in the sagittal plane ruled out ossification of the ligamentum flavum. Magnetic resonance imaging of the neck failed to demonstrate the calcifications but was useful in evaluating the severity of the spinal cord compression. One patient had articular chondrocalcinosis in both knees and another had calcifications in the basal ganglia. Surgical decompression by the posterior route was performed in two patients and was effective in both, whereas two of the three symptomatic patients who did not have surgery experienced worsening neurological loss. Analysis of the operative specimens from the two surgically treated patients showed a mixture of calcium pyrophosphate dihydrate crystals and apatite microcrystals. Conclusion. Calcification of the ligamentum flavum is probably underrecognized in blacks. This condition causes severe neurological loss. Imaging studies provide the diagnosis. The pathogenesis remains unclear.     

The Increased Expression of Matrix Metalloproteinases Associated with Elastin Degradation and Fibrosis of the Ligamentum Flavum in Patients with Lumbar Spinal Stenosis

Background

One of the characteristics of spinal stenosis is elastin degradation and fibrosis of the extracellular matrix of the ligamentum flavum. However, there have been no investigations to determine which biochemical factors cause these histologic changes. So we performed the current study to investigate the hypothesis that matrix metalloproteinases (MMPs), which possess the ability to cause extracellular matrix remodeling, may play a role as a mediator for this malady in the ligamentum flavum.

Methods

The ligamentum flavum specimens were surgically obtained from thirty patients with spinal stenosis, as well as from 30 control patients with a disc herniation. The extents of ligamentum flavum elastin degradation and fibrosis were graded (grade 0-4) with performing hematoxylin-eosin staining and Masson''s trichrome staining, respectively. The localization of MMP-2 (gelatinase), MMP-3 (stromelysin) and MMP-13 (collagenase) within the ligamentum flavum tissue was determined by immunohistochemistry. The expressions of the active forms of MMP-2, MMP-3 and MMP-13 were determined by western blot analysis, and the blots were quantified using an imaging densitometer. The histologic and biochemical results were compared between the two conditions.

Results

Elastin degradation and fibrosis of the ligamentum flavum were significantly more severe in the spinal stenosis samples than that in the disc herniation samples (3.14 ± 0.50 vs. 0.55 ± 0.60, p < 0.001; 3.10 ± 0.57 vs. 0.76 ± 0.52, p < 0.001, respectively). The expressions of the active form of MMPs were identified in all the ligamentum flavums of the spinal stenosis and disc herniation patients. The expressions of active MMP-2 and MMP-13 were significantly higher in the spinal stenosis samples than that in the disc herniation samples (both p < 0.05). The expression of active MMP-3 was slightly higher in the spinal stenosis samples than that in the disc herniation samples, but the difference was not statistically significant (p = 0.131). MMP-2, -3, and -13 were positively stained on the ligamentum flavum fibroblasts.

Conclusions

The current results suggest that the increased expression of active MMPs by the ligamentum flavum fibroblasts might be related to the elastin degradation and fibrosis of the ligamentum flavum in the patients who suffer with lumbar spinal stenosis.     

Six cases of cervical ligamentum flavum calcification in Blacks in the French West Indies

OBJECTIVE: Calcification of the ligamentum flavum at the cervical spine is an uncommon condition reported mainly in Japanese patients. We describe the clinical manifestations, imaging study findings, and outcomes in six cases seen in the French West Indies. MATERIAL and METHODS: We retrospectively reviewed the medical charts of six patients admitted to an orthopedics department for spinal cord compression shown upon computed tomography to be caused by calcification of the ligamentu flavum. There were five women and one man, mean age at admission was 71.7 years (range, 64-79 years) and all six patients were Black. RESULTS: Five patients had cervical myelopathy and one was asymptomatic. All five symptomatic patients had cervical spinal stenosis, explaining the rapid symptom onset (within six and a half months) and severe motor loss. Computed tomography reconstruction in the sagittal plane ruled out ossification of the ligamentum flavum. Magnetic resonance imaging of the neck failed to demonstrate the calcifications but was useful in evaluating the severity of the spinal cord compression. One patient had articular chondrocalcinosis in both knees and another had calcifications in the basal ganglia. Surgical decompression by the posterior route was performed in two patients and was effective in both, whereas two of the three symptomatic patients who did not have surgery experienced worsening neurological loss. Analysis of the operative specimens from the two surgically treated patients showed a mixture of calcium pyrophosphate dihydrate crystals and apatite microcrystals. CONCLUSION: Calcification of the ligamentum flavum is probably underrecognized in blacks. This condition causes severe neurological loss. Imaging studies provide the diagnosis. The pathogenesis remains unclear.