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PubMed1988

Pathological changes in the cartilaginous plates in relation to intervertebral disc lesions.

Three hundred sixty-eight intervertebral discs (T11/12-L5/S1) were obtained at autopsy from 61 individuals (36 male, 25 female) ranging from 25 to 85 years of age, and subsequently examined histopathologically as sagittal-sectioned specimens with special reference to the cartilaginous plates. The numbers of cartilaginous foci found in fissured and ruptured regions of the plates were found to increase with age, and were considered to represent a restoration mechanism. Measurement of the cartilaginous plate/intervertebral disc antero-posterior length ratio showed a decrease with age in intervertebral discs from the same spinal level. Therefore, cartilage cell proliferation in the vertebral body rim was found following rupture of the outer layer of the annulus fibrosus and was thought to be one of the causes of spur formation in spondylosis deformans. When the changes in a cartilaginous plate with aging were accompanied by destructive processes of the vertebrae such as osteoporosis or metastatic cancer, an increase in the height of the disc, or ballooning, developed. On the other hand, when degeneration of the intervertebral disc increased and the nucleus pulposus collapsed, the height of the disc decreased. Thus, although the cartilaginous plate exhibits a restoration mechanism, degeneration with age progresses, resulting in various disc lesions.

Adult↗
PubMed2004

The role of collagen IX tryptophan polymorphisms in symptomatic intervertebral disc disease in Southern European patients.

STUDY DESIGN: We conducted a cross-sectional, genotyping study of intervertebral disc disease patients and controls. OBJECTIVES: To determine the contribution of COL9A2 and COL9A3 Tryptophan polymorphisms to intervertebral disc disease development in a genetically heterogeneous, Southern European population compared to previous Finnish studies. SUMMARY OF BACKGROUND DATA: The COL9A2 and COL9A3 genes encode the alpha2 and alpha3 chains of Collagen IX. Recent Finnish studies suggest that a tryptophan polymorphism in the COL9A2 gene (Trp2) results in hereditary intervertebral disc disease, whereas a similar tryptophan mutation in COL9A3 (Trp3) conveys a 3-fold risk of intervertebral disc disease. METHODS: We studied 105 symptomatic patients with radiographically and/or surgically proven lumbar (98%, n = 103) or cervical (2%, n = 2) intervertebral disc disease and 102 age-matched controls without spinal complaints from hospitals in Athens, Greece. Intervertebral disc disease was defined as significant disc herniation resulting in persistent back or leg pain. We genotyped all patients for COL9A2 and COL9A3 allele variations using a polymerase chain reaction-based technique. RESULTS: None of our patients had the Trp2 allele. Consistent with previous Finnish findings, more Greek intervertebral disc disease cases (8.6%) than controls (4.9%) had at least 1 Trp3 allele, but this difference did not reach statistical significance (P = 0.293). The allele frequency of the Trp3 mutation was significantly higher among previously studied Finnish patients with intervertebral disc disease (12.3%) than among the Southern European patients with intervertebral disc disease in our study (4.3%), P = 0.001. CONCLUSIONS: The differences in Trp allele frequency we found between Greek and Finnish patients with intervertebral disc disease most likely represent true differences in polymorphism prevalence between the respective populations. The 2 previously described Trp alleles in COL9A2 and COL9A3 are likely to be less significant susceptibility factors for intervertebral disc disease development in Southern European populations.

Adult↗
PubMed2003

Geometric and morphological changes of the intervertebral disc under fatigue testing.

OBJECTIVE: To understand the injury mechanism of the intervertebral disc at different loading rates and to explore the anatomic and histological changes of intervertebral discs. DESIGN: Fresh porcine lumbar spines were used for fatigue testing to study the morphological changes of the intervertebral disc. BACKGROUND: Intervertebral disc problem is one of the most common causes that lead to low back pain. Slow repetitive loading was considered to be the critical factor of spine and disc injuries. METHODS: Twenty-four lumbar functional units were subjected to cyclic loading at three different loading rates. The geometric measurements and magnetic resonance image observations were conducted for the comprehension of morphological changes. The detail observation was taken through a stereomicroscope. RESULTS: There was no significance in geometric changes between different loading rates. For magnetic resonance imagings, morphological changes included the changes of nucleus pulposus shape, bulge of anterior and posterior longitudinal ligaments, and dehydration in annulus fibrosus. CONCLUSION: The morphological changes of intervertebral disc were revealed in certain kinds of lesions. The results imply that fatigue failure and degeneration or instability are strongly linked. The correlation of magnetic resonance imaging and anatomic observation showed a high correspondence in the comparison of shape and position of the nucleus pulpasus. RELEVANCE: The changes of geometric measurements and relationship between anatomic observation and magnetic resonance imaging finding had been analyzed. It could help in understanding the mechanism of triggering cause in the early stage of disc degeneration.

Animals↗
PubMed1989

[Magnetic resonance imaging of diseased cervical and lumbar intervertebral discs].

Magnetic resonance images (MRI) of diseased cervical and lumbar intervertebral discs involving both intrinsic and extrinsic cord lesions were examined using either a 0.15 T resistive or a 0.5 T superconductive magnetic imaging system. High resolution images were obtained by means of a surface coil in most cases. The vertebrae, intervertebral discs, and spinal cord were delineated in greatest detail on spin-echo (SE) images with a long repetition time (TR) and a short echo time (proton density-weighted image), on which the spinal cord was appreciated without overshadowing by the cerebrospinal fluid-filled subarachnoid space. Protrusion of degenerated intervertebral discs into the spinal canal was clearly demonstrated not only on sagittal but also on parasagittal and transverse views. The location of protruded discs and compression of the spinal cord, caudal sac, and nerve roots were well visualized three-dimensionally. Pathological features of intervertebral discs were better appreciated on T2-weighted images with long TR and SE pulse sequences. Degeneration of intervertebral discs resulted in decreased signal intensity in cases involving lumbar disc lesions but not those involving cervical disc lesions. In a case of suspected myelomalacia, the intrinsic cord lesion resulting from traumatic disc protrusion appeared as focal low signal intensity on T1-weighted images and as somewhat high intensity on T2-weighted images. The inversion recovery sequence with median inversion time displayed an inferior image of low contrast and was judged uninformative in comparison to SE images. The authors' observations demonstrate that MRI is an essential diagnostic technique for spinal cord disorders.(ABSTRACT TRUNCATED AT 250 WORDS)

Cervical Vertebrae↗
PubMed1998

A new culture system to study the metabolism of the intervertebral disc in vitro.

STUDY DESIGN: This study determined whether entrapment of a rabbit intervertebral disc in alginate gel helped to promote the retention of normal metabolic activities by the nucleus pulposus and anulus fibrosus in tissue culture. OBJECTIVES: To establish an in vitro culture system to study the metabolism of the intervertebral disc as a whole integral organ. SUMMARY OF BACKGROUND DATA: In vitro studies of the metabolism of intervertebral discs have been scarce because of the difficulties involved in maintaining the integrity of the tissues, especially that of the nucleus pulposus, in culture medium. METHODS: Rabbit intervertebral discs were embedded in alginate gel and maintained in culture for as long as 1 month. At weekly intervals, experiments were performed to measure the rate of proteoglycan synthesis and to characterize proteoglycans newly synthesized by cells in the anulus fibrosus and nucleus pulposus. In addition, at these same time intervals, the contents of sulfated proteoglycans, antigenic keratan sulfate, hyaluronan, and collagen in these two intervertebral disc tissues were measured to evaluate tissue integrity. Intervertebral discs cultured in medium alone were used as controls and analyzed in parallel. RESULTS: The anulus fibrosus and nucleus pulposus of intervertebral discs cultured in alginate gel sustained a higher rate of proteoglycan synthesis and maintained a higher content of extracellular matrix components than the respective controls at all times. CONCLUSIONS: This new alginate tissue culture system should prove useful for studying the metabolism of whole intervertebral discs.

Alginates↗
PubMed1996

Effects of degeneration on the elastic modulus distribution in the lumbar intervertebral disc.

STUDY DESIGN: Local elastic moduli of sliced intervertebral disc specimens were studied after establishing the relation between the elastic modulus and indentation behaviors by model tests using polyurethane specimens. OBJECTIVES: This study presents a method to quantify the distribution of compressive elastic moduli in the lumbar intervertebral disc and to clarify the effects of degeneration on the distribution. SUMMARY OF BACKGROUND DATA: No study has been performed to evaluate the distribution of axial compressive elastic moduli, which is supposed to relate previous biomechanical, biological, and biochemical findings regarding the intervertebral disc. METHODS: Local compressive elastic moduli of the intervertebral disc were estimated by indentation tests. To evaluate the distribution of elastic moduli, indentation tests were performed at nodal points of a 10 mm x 10 mm network on a specimen. Nine cadaveric lumbar discs (L3-L4 and L4-L5) with various degrees of degeneration were tested. The age of subjects ranged 39 to 90 years (mean, 58.4 years). RESULTS: The distribution of elastic moduli in normal discs was symmetric about the midsagittal plane. The mean elastic modulus in the nucleus pulposus was 5.8 kPa and those of the anterior and posterior anulus fibrosus were 110.7 and 75.8 kPa, respectively. The elastic moduli in the lateral portions were the lowest in the normal anulus, and were close to the values of the nucleus. Compared to normal discs, degenerated discs showed irregular distributions of elastic moduli. The elastic moduli of the degenerated nucleus were higher than those in normal discs. CONCLUSIONS: The distribution of elastic moduli is much different between discs with and without degeneration.

Adult↗
PubMed1993

The histology of lumbar intervertebral disc herniation. The significance of small blood vessels in the extruded tissue.

Six hundred surgical cases of lumbar intervertebral disc herniation were evaluated histologically for the presence of blood vessels. These patients ranged in age from 12 to 77 years. Blood vessels were observed in 57 of 101 cases of complete prolapse type of herniated disc (56.4%), 12 of 32 cases of incomplete prolapse type of herniated disc (37.5%), and 53 of 467 cases of protrusion type of intervertebral disc herniation (11.3%). The presence of blood vessels in intervertebral discs was also investigated in postmortem specimens. Blood vessels were observed in 293 of 616 intervertebral discs (T10-L5), in individuals older than 40 years of age from 100 postmortem spines. The specimen age range was 16-89 years. Most of the blood vessels seen in the extruded tissue, exposed to the epidural space in cases of complete and incomplete prolapse type of herniation, are thought to have been newly formed after herniation occurred. As invasion of the intervertebral disc by blood vessels was found to occur with the advance of age, it is possible that such blood vessels become extruded with the intervertebral disc tissue. The intervertebral disc may herniate posteriorly in three basic patterns. The first pattern is "protrusion type of herniated disc." In protrusion hernia type there is abnormal posterior bulging of the anulus fibrosus. The disc pathology is predominantly nucleus pulposus, and the peripheral layer of the anulus fibrosus remains attached to the vertebral body bony rim, however.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1998

Effects of steroid and lipopolysaccharide on spontaneous resorption of herniated intervertebral discs. An experimental study in the rabbit.

STUDY DESIGN: Histologic examination was performed on autografted intervertebral disc materials of rabbit models, which were partially incised through a retroperitoneal approach at L1-L2 and grafted within the posterior epidural space at L4. OBJECTIVE: To evaluate whether the resorption process of the herniated intervertebral disc is influenced and controlled by treatments with medications. SUMMARY OF BACKGROUND DATA: Regarding resorption of herniated intervertebral discs, recent studies of magnetic resonance images and histologic investigations of surgically resected specimens in lumber disc herniation patients have been reported. It has been shown that inflammatory factors may play an important role in the mechanism of resorption of the herniated intervertebral disc. However, little is known about the origin of newly formed vessels and inflammatory cells detected in herniated disc specimens from patients. In this study, The resorption process of disc material grafted into the epidural space was observed in a rabbit model. METHODS: Thirty-six adult rabbits were used. The L1-L2 intervertebral disc was partially incised through a retroperitoneal approach. The harvested disc material, which contains the nucleus pulposus and the anulus fibrosus were placed into the posterior epidural space at L4 of the same rabbit. The animals were divided into control, and steroid groups. The control group received no treatment after surgery. In the lipopolysaccharide group, rabbits were injected 1 mg/kg into the peritoneum immediately and at 7 days after surgery. In the steroid group, rabbits were injected with 1 mg/kg betamethasone into the epidural space daily from 1 to 7 days after surgery. Rabbits of each group were killed for histologic examination at 1, 2, 4, and 8 weeks after surgery. RESULTS: At 1 and 2 weeks after surgery, inflammatory cells and newly formed vessels were more frequently observed in the lipopolysaccharide group than in the control and steroid groups. At 4 weeks after surgery, derangement and loosening of collagen fibers were also observed in the lipopolysaccharide group. At 8 weeks after surgery, fragmentation and partial disappearance of matrix were observed in the control and lipopolysaccharide groups. Most of the intervertebral discs were replaced by fibrous tissues in the lipopolysaccharide group. However, the matrix of the intervertebral disc almost remained. CONCLUSIONS: Autologous intervertebral disc material grafted into the epidural space was penetrated by newly formed vessels produced from the epidural fat tissue and resolved as the result of inflammatory reaction. Lipopolysaccharide accelerated the replacement of grafted intervertebral disc by fibrous tissue, which suggests the resorption of the disc in the epidural space of the rabbit, whereas high-dose steroid suppressed the replacement.

Animals↗
PubMed2002

The effect of hydration on the stiffness of intervertebral discs in an ovine model.

OBJECTIVE: To determine the hydration-over-time behaviour of ovine intervertebral discs and intact joints in a saline bath at body temperature and the effect this has on their stiffness compared to air at ambient temperature. DESIGN: The hydration-over-time behaviour and stiffness of the ovine functional spinal unit and disc were quantified. BACKGROUND: The fluid content of an intervertebral disc is not constant but varies with external load and load history. The stiffness of ovine functional spinal units in a hydrated environment and how this compares to testing in air have not been quantified. METHODS: Intervertebral discs and functional spinal units were weighed and soaked in a saline water bath at 37 degrees C and reweighed each hour for 6 h. They were then allowed to stand in air at room temperature while the time to return to initial weight was recorded. Functional spinal units were randomly assigned to two groups. Axial compression, flexion, extension, lateral bending and axial torsion tests were performed on both the intact functional spinal unit and isolated disc. Group 1 was tested in air then in a saline water bath at 37 degrees C with the testing order reversed for Group 2. RESULTS: Hydration of the disc reached a plateau after an average 3-4 h of soaking with the largest increase seen in the first hour. Four hours, standing in air at room temperature, was required to return specimens to their initial weight. The functional spinal unit stiffness was significantly lower for those specimens tested in the bath compared to air. CONCLUSIONS: Ovine intervertebral discs show similar hydration-over-time behaviour when compared to human discs. Stiffnesses in different modes of loading were significantly different when tested in a hydrated environment compared with the standard method of testing in air. RELEVANCE: It has been shown that there are biomechanical and biochemical similarities between sheep and human intervertebral discs. Despite these similarities, no studies have looked at how ovine intervertebral discs behave over time in a hydrated environment. In humans, hydration levels are an important aspect of intervertebral disc degeneration. There is also a relationship between decreased hydration levels and increased stiffness. This study demonstrates the similarities between human and ovine hydration-over-time behaviour. The importance of intervertebral disc hydration and its effects on stiffness under different modes of loading were also demonstrated and have not been previously shown using the ovine model. In this context, the results from this study provide further support for the use of the ovine model.

Analysis of Variance↗
PubMed2006

Immunolocalization of thrombospondin in the human and sand rat intervertebral disc.

STUDY DESIGN: Human intervertebral disc tissue from the anulus was obtained in a prospective study investigating the presence of the matricellular protein thrombospondin (TSP) in human and sand rat discs. Studies were approved by the authors' Human Subjects Institutional Review Board and Institutional Animal Care and Use Committee. OBJECTIVES: To determine whether TSP could be detected in the human or sand rat disc with immunohistochemistry, and to assess its localization. SUMMARY OF BACKGROUND DATA: The role of the matricellular proteins in maintenance of disc health and extracellular matrix remodeling is as yet poorly understood. SPARC and tenascin have previously been shown to be present in the human disc. TSP has a well-recognized antiangiogenic activity in vivo and in vitro. METHODS: Sixteen specimens of human disc tissue and discs from 7 sand rats were assessed for immunohistochemical localization of TSP. Three human disc cell cultures grown in three-dimensional culture were also evaluated. RESULTS.: Strong immunoreactivity was present in the outer anulus of both human and sand rat discs. Inner anulus showed lesser localization. In clusters, both immuno-positive and -negative cells were present. Similar patterns of localization were seen in the sand rat specimens. Human disc cells in three-dimensional culture produced abundant TSP. CONCLUSIONS: The biologic basis for the avascular adult human disc does not appear to have been explored. Since TSP has recognized antiangiogenic effects both in vitro and in vivo, we suggest that the strong immunolocalization of TSP in the outer anulus indicates a role for TSP in the avascular status of the adult human and sand rat disc.

Adolescent↗
PubMed2003

Ultrasound imaging of the intervertebral disc.

STUDY DESIGN: In vitro ultrasound imaging of dog intervertebral discs was performed. OBJECTIVE: To determine the reliability of ultrasound imaging in the detection of structural changes associated with disc pathology. SUMMARY OF BACKGROUND DATA: Little work has been done to evaluate the potential applications of ultrasound in the imaging of intervertebral discs. Initial in vitro studies, however, have indicated that ultrasound imaging is capable of producing images of the disc that contain a high degree of structural information. METHODS: Explanted lumbosacral discs from 13 nonchondrodystrophic dogs, mean age 5 years and 8 months, were stripped of all surrounding tissues and scanned using ultrasound before being sectioned and photographed. The ultrasound images were graded according to criteria chosen to reflect progressive stages of disc degeneration, allowing correlation with the grading scale used to assess the photographic images of the discs. Grades assigned to each disc were compared using Cronbach's alpha to determine the reliability of the images obtained using ultrasound. RESULTS: The results for the anterior anulus fibrosus produced an alpha value of 0.924; those for the nucleus pulposus produced a value of 0.821; whereas those for the posterior anulus fibrosus produced a value of 0.882. Where the grade given to the ultrasound image did not match those given in visual assessment, the disparity was never greater than one grade. Ultrasound images of several discs demonstrated echo patterns that matched, in both location and appearance, real structural defects identifiable on the sectioned discs. CONCLUSIONS: Ultrasound images of intervertebral discs relate well to their pathologic condition. In addition, ultrasound is able to locate specific pathologic defects.

Animals↗
PubMed2005

Human intervertebral disc aggrecan inhibits endothelial cell adhesion and cell migration in vitro.

STUDY DESIGN: The effect of human intervertebral disc aggrecan on endothelial cell growth was examined using cell culture assays. OBJECTIVE: To determine the response of endothelial cells to human intervertebral disc aggrecan, and whether the amount and type of aggrecan present in the intervertebral disc may be implicated in disc vascularization. SUMMARY OF BACKGROUND DATA: Intervertebral disc degeneration has been associated with a loss of proteoglycan, and the ingrowth of blood vessels and nerves. Neovascularization is a common feature also of disc herniation. Intervertebral disc aggrecan is inhibitory to sensory nerve growth, but the effects of disc aggrecan on endothelial cell growth are not known. METHODS: Aggrecan monomers were isolated separately from the anulus fibrosus and nucleus pulposus of human lumbar intervertebral discs, and characterized to determine the amount and type of sulfated glycosaminoglycan side chains present. The effects of these aggrecan isolates on the cellular adhesion and migration of the human endothelial cell lines, HMEC-1 and EAhy-926, were examined in vitro. RESULTS: Homogenous substrata of disc aggrecan inhibited endothelial cell adhesion and cell spreading in a concentration dependent manner. In substrata choice assays, endothelial cells seeded onto collagen type I migrated over the collagen until they encountered substrata of disc aggrecan, where they either stopped migrating, retreated onto the collagen, or, more commonly, changed direction to align along the collagen-aggrecan border. The inhibitory effect of aggrecan on endothelial cell migration was concentration dependent, and reduced by enzymatic treatment of the aggrecan monomers with a combination of chondroitinase ABC and keratinase/keratinase II. Anulus fibrosus aggrecan was more inhibitory to endothelial cell adhesion than nucleus pulposus aggrecan. However, this difference did not relate to the extent to which the different aggrecan isolates were charged, as determined by colorimetric assay with 1,9-dimethylmethylene blue, or to marked differences in the distribution of chondroitin sulfated and keratan sulfated side chains. CONCLUSIONS: Human intervertebral disc aggrecan is inhibitory to endothelial cell migration, and this inhibitory effect appears to depend, in part, on the presence of glycosaminoglycan side chains on the aggrecan monomer.

Aggrecans↗
PubMed2004

Distinction between the extracellular matrix of the nucleus pulposus and hyaline cartilage: a requisite for tissue engineering of intervertebral disc.

Tissue engineering of intervertebral discs (IVD) using mesenchymal stem cells (MSCs) induced to differentiate into a disc-cell phenotype has been considered as an alternative treatment for disc degeneration. However, since there is no unique marker characteristic of discs and since hyaline cartilage and immature nucleus pulposus (NP) possess similar macromolecules in their extracellular matrix, it is currently difficult to recognize MSC conversion to a disc cell. This study was performed to compare the proteoglycan to collagen ratio (measured as GAG to hydroxyproline ratio) in the NP of normal disc to that of the hyaline cartilage of the endplate within the same group of individuals and test the hypothesis that this ratio can be used for in vivo studies to distinguish between a normal NP and hyaline cartilage phenotype. Whole human lumbar spine specimens from fresh cadavers, ranging in age from 12 weeks to 79 years, were used to harvest the IVDs and adjacent endplates. The GAG to hydroxyproline ratio within the NP of young adults is approximately 27:1, whereas the ratio within the hyaline cartilage endplate of the same aged individuals is about 2:1. The production of an extracellular matrix with a high proteoglycan to collagen ratio can be used in vivo to distinguish NP cells from chondrocytes, and could help in identifying a NP-like phenotype in vivo as opposed to a chondrocyte when MSCs are induced to differentiate for tissue engineering of a disc.

Adolescent↗
PubMed1975

Calcification of intervertebral discs in childhood.

Over 75 cases of intervertebral disc calcification in childhood have been reported, but the illness is seldom considered in the differential diagnosis of back pain inchildren. This paper reports two children who required surgery for intervertebral disc calcification. The histologic changes, which have not been described previously, include an amorphous calcification within the nucleus pulposus without any inflammatory reaction. The etiology of disc calcification remains unknown, but it can be differentiated both clinically and pathologically from other causes of calcified intervertebral discs and from spondylarthritis.

Biopsy↗
PubMed2001

New use of a three-dimensional pellet culture system for human intervertebral disc cells: initial characterization and potential use for tissue engineering.

STUDY DESIGN: Human intervertebral disc cells were cultured in a new three-dimensional "pellet culture" system as an alternative to conventional alginate bead microspheres. Histologic, biochemical, and immunohistologic assays were performed to characterize this new culturing method for disc cells. The feasibility of using the pellet culture system to study effects of gene therapy was also assessed. OBJECTIVES: To characterize a new and simpler, three-dimensional culture system for human intervertebral disc cells and to assess the feasibility of its use for gene therapy and tissue engineering studies. SUMMARY OF BACKGROUND DATA: The alginate microsphere three-dimensional culture system has been the most utilized culture method for disc cells, but it is technically difficult and has some disadvantages. Recently, the "pellet culture" method, a simpler three-dimensional culture system, was described for bone marrow stromal cells. This simpler method might be useful for in vitro and in vivo studies of disc cells as well as for delivery of exogenous genes. METHODS: Isolated human intervertebral disc cells were centrifuged at low speeds to form aggregates and allowed to grow as pellets for up to 3 weeks. At various times these pellet cultures were analyzed grossly, histologically, and immunohistologically. Their ability to incorporate [35S]sulfate in their response to TGF-beta1 was also analyzed. The ability of these pellets to deliver and express exogenous genes in vivo was analyzed by implantation of pellet cultures in muscles of SCID mice. RESULTS: Within several days the intervertebral disc cells were able to form mature three-dimensional aggregates that were each well encapsulated by a fibrous capsule. These pellets successfully synthesized proteoglycan and collagen Type II matrix as determined by histology and immunohistochemistry. In response to TGF-beta1, the pellets increased synthesis of proteoglycan and collagen Type II. When implanted into thigh muscles of SCID mice, the pellets remained aggregated and expressed the beta-galactosidase marker gene in vivo for up to 2 weeks. CONCLUSIONS: The pellet culture system is a new and technically simple method to culture human intervertebral disc cells. The majority of the human intervertebral disc cells retained their native phenotype in this three dimensional system and expressed a marker gene both in vitro and in vivo. Thus, this pellet system might be useful for in vitro and in vivo biochemical studies as well as for studies involving gene therapy and tissue engineering.

Adult↗
PubMed1994

Isolation and characterization of metallic wear debris from a dynamic intervertebral disc prosthesis.

A dynamic intervertebral disc prosthesis (DIDP) has been developed. It consists of a CoCrMo body and uses Ti6Al4V springs to replicate the mechanical function of the lumbar joint. Wear studies have been performed previously on the DIDP using two specialized simulators to test the wear properties of the moving parts of the disc prosthesis. A pin-in-slot simulator generates wear that would occur in the hinge-pin assembly of the prosthesis. A spring-in-pocket simulator approximates the conditions under which the springs would wear against the body of the prosthesis. The spring-pocket interface is responsible for the production of approximately 90% of the total wear occurring in the prosthesis, and is therefore the main focus of this study. Bovine serum with a preservative has been used as a lubricant in both simulators. The spring-in-pocket simulator compares the effects of two different manufacturing techniques of CoCrMo (HIPing and forging) on their wear characteristics against Ti6Al4V springs. Debris from the spring-in-pocket simulator has been isolated from the serum lubricant and characterized using scanning electron microscopy techniques. The morphology of the Ti6Al4V fragments is rough and irregularly shaped. The size of these fragments ranges from < 1 microns to > 30 microns. The forged CoCrMo alloy debris has an irregular polyhedral shape, with sizes in the same range as the spring fragments. The morphology of the HIPed CoCrMo debris is spherical with a size range < 5 microns to > 30 microns. Length and width measurements of micron-size particles were made with the particle measurements feature of the scanning electron microscope. Micron-size particles were found in all stations. This article provides a unique way to isolate and analyze debris from serum lubricants used in simulators.

Alloys↗
PubMed2001

Biochemical and morphological changes in herniated human intervertebral disc.

The molecular and morphologic features of herniated human intervertebral disc tissues are of particular importance to clarify the pathogenesis. The present study analyzed the biochemical and morphological features of herniated intervertebral disc tissues to determine the constituent factors responsible for intervertebral disc herniation. A total of 32 herniated disc specimens and 4 control disc samples were analyzed. Collagen subunit composition, collagenase activity, lipid peroxidation level, caspase-3 activity, metal levels, morphologic studies, and genetic analysis were performed on herniated disc tissues of chronic (group A) and acute (group B) group and compared with findings of control group. Nick translation analysis in situ revealed apoptotic-positive stained DNA fragments as black-brown spots in herniated disc tissues. The presence of type II collagen in control disc samples and its absence in herniated samples were confirmed immunohistochemically. The increased caspase-3 activity, the apoptotic-positive stained DNA fragments, and the electron microscopic findings suggest enhanced programmed cell death in herniated discs. The significant increase in lipid peroxidation levels and collagenase activity, and the low metal levels suggest the enhancement of cell death signals in herniated discs, caused by oxygen stress. Linkage analysis of herniated disc tissues in Japanese individuals may suggest ethnic variation. These findings may be helpful in understanding the pathogenesis of herniated disc disease.

Adolescent↗
PubMedDate not supplied

Herniated intervertebral disc without pain.

The diagnosis of herniated intervertebral disc is often made in cases of radicular pain in the low back, the neck, or sciatica or brachialgia. Practitioners often call upon radiologic imaging to confirm this diagnosis. But on radiologic examination, such a herniation may consist of a bulge, protrusion, prolapse, extension, extrusion or sequestration of this disc. We define and illustrate these terms from the literature. We then review the radiologic studies of normal controls, who have never had sciatica, brachialgia or pain in the low back or neck. In over one-quarter of these controls, studies using the plain x-ray, CT scan, myelogram, and MRI show various radiologic signs of a herniated intervertebral disc. We therefore recommend that practitioners should not exclusively rely on radiologic imaging to confirm the clinical diagnosis of a herniated intervertebral disc.

Aging↗