To see the other types of publications on this topic, follow the link: Human thoracic intervertebral disc.
Dissertations / Theses on the topic 'Human thoracic intervertebral disc'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 29 dissertations / theses for your research on the topic 'Human thoracic intervertebral disc.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Tan, Celia I. C. "A radiological and biochemical perspective on ageing and degeneration of the human thoracic intervertebral disc." University of Western Australia. School of Surgery and Pathology, 2004. http://theses.library.uwa.edu.au/adt-WU2004.0059.
Full textAbstract:
Disc degenerative changes are directly or indirectly associated with spinal pain and disability. Literature revealed a high prevalence of disc degeneration in the thoracic region, however thoracic MRI degeneration trends and information on disc biochemical matrix constituents are limited for thoracic discs compared to lumbar and cervical discs. The objective of this thesis was to use MRI to investigate the prevalence of disc degenerative changes affecting the human thoracic spine, and to determine the factors affecting spinal disc biochemical matrix. A 3-point subjective MRI grading scale was used to grade the films. The feasibility of using archived formalin-fixed cadaver material was investigated to analyse collagen and elastin crosslinks. The prevalence of degenerative changes in human thoracic discs and vertebrae (T1 to T12) was determined retrospectively from an audit of 216 MRI cases, using sagittal T1- and T2-weighted MR images. In a subsequent series of ex-vivo studies, human thoracic discs and LF from 26 formalin-fixed and two fresh spines, involving all thoracic levels, were examined macroscopically to determine the degeneration status. Subsequently, disc and ligament tissues were analysed biochemically for collagen (pyridinoline and deoxypyridinoline) and elastin (desmosine and isodesmosine) crosslinks. These crosslinks were extracted from hydrolysed samples by cellulose partition chromatography, and analysed by reverse-phase HPLC. Collagen content was determined using its hydroxyproline content, and proteoglycan content was assayed using a modified DMB assay for chondroitin sulphate. Finally the MRI and macroscopic assessments of thoracic discs, were compared with the biochemical data from two fresh cadaver thoracic spines. The 3-point MRI grading scale had a high inter- (k = 0.57 to 0.78) and intra-rater (k = 0.71 to 0.87) reliability. There were no significant differences in the collagen and elastin content and extent of collagen crosslinks between formalin fixed and unfixed ligament and disc tissues, after 25 weeks of formalin fixation. From the in-vivo MRI series of investigations (n = 216 MRI films), the prevalence of thoracic disc degenerative and vertebral morphological changes revealed significant age, gender and spinal level trends (p < 0.05).Generally, males had a higher propensity for disc degeneration in contrast to females, especially older females, where the trend showed a higher prevalence of osteophytes and vertebral body changes. In particular, the mid and lower thoracic levels have a higher prevalence of degenerative changes, except for osteophytes and anterior vertebral wedging. With increased age, there was a concomitant increase in anterior wedging and bi-concavity and disc degenerative changes except for end-plates. The biochemical investigations on the ex-vivo series of formalin-fixed thoracic discs (n = 303) also revealed significant changes in the disc matrix due to degeneration status, age, gender and spinal regional factors. With increased age, normal disc matrices have significantly lower collagen content and extent of pyridinoline (p < 0.001). In contrast, the degenerated disc matrix revealed significantly higher collagen content and extent of deoxypyridinoline (p < 0.05). These findings suggest that an altered matrix existed in normal ageing discs, which render the disc prone to injury and degeneration over the life span. The higher collagen and deoxypyridinoline in degenerated disc matrices reflects an increase in chondrocyte synthesis, and is also a novel finding, suggesting that they may be used as markers of ageing and degeneration processes. The biochemical investigations on another series of ex-vivo spinal LF tissues (n = 364), revealed that this had a lower collagen and pyridinoline, but significantly higher elastin and deoxypyridinoline compared to spinal discs (p < 0.05). Elastin crosslinks however were difficult to detect in spinal discs, being present in negligible amounts in a few lumbar discs. The elastin crosslinks in the LF were not significantly affected by age, but were significantly higher in calcified, and female ligamentum tissues, and also in the lumbar region (p < 0.05). These MRI prevalence findings enhanced our knowledge of vertebral body and disc degeneration trends in the thoracic region and contributed to the interpretation of MR images for pathology in the human thoracic spine. Information on the associated collagenous and elastic changes in the disc and ligamentum matrices provide original data and insight on the pathogenesis of degeneration in the disc matrix from a biochemical perspective, highlighting gender, age and spinal level influences on the matrix tensile strength and cellular synthetic activities.
2
Liu, Jane J. "Proteoglycans of the human intervertebral disc." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68204.
Full textAbstract:
The composition and heterogeneity of human intervertebral disc proteoglycans from different aged individuals were investigated. (1) The glycosaminoglycan content in the nucleus pulposus was greater than that in the annulus fibrosus at all ages. Glycosaminoglycan content increased from the infant to the young adult, and then decreased from the young to the mature adult. (2) Disc contained a higher content of hyaluronate than articular cartilage at all ages. (3) Proteolytically modified LP3 was predominant in the disc. (4) Very low link protein concentrations were observed in adult disc proteoglycan preparations and adult disc extracts analysed by SDS/PAGE and immunoblotting suggesting a deficiency in link protein content. In contrast, radioimmunoassay of disc extracts suggests no deficiency in link protein content. (5) The existence of extremely fragmented link protein in adult disc is postulated to reconcile the results of the two analytic methods. (6) Non-proteoglycan forms of biglycan and decorin are present in the disc. The difference between the two non-proteoglycan forms of biglycan appears to be due to different N-linked oligosaccharide substitution rather than proteolysis.
3
Pockert, Aneta Joanna. "Aggrecanolytic ADAMTS Expression in Human Intervertebral Disc Degeneration." Thesis, University of Manchester, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492880.
Full textAbstract:
Low Back Pain (LBP) affects 60-80% of the population at some point in their lives with approximately 10% of sufferers being chronically disabled. Degeneration of the intervertebral disc (DIVD) has been identified as one of the main causes of LBP.
4
Antoniou, John. "Quantitative biochemical changes in the human lumbar intervertebral disc." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0028/NQ50103.pdf.
Full text
5
Frain, Jennie. "The effects of mechanical load on human intervertebral disc cells." Thesis, University of Manchester, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493463.
Full textAbstract:
The precise mechanisms by which human intervertebral discs (IVD) respond to load remains unknown and are a challenge to investigate in vitro. In this study, a novel mechanical loading system was devised, built, tested and successfully used to apply hydrostatic pressure to nucleus pulposus (NP) and annulus fibrosis (AF) cells and explants obtained from human nondegenerate and degenerate IVD. Cells were removed from the IVD, cultured in monolayer to generate sufficient numbers and subsequently embedded in alginate constructs prior to application of dynamic cyclic hydrostatic pressure at physiological levels.
6
Chak-Sum, S. Ng. "The connective tissue degrading enzyme system of the human intervertebral disc." Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376277.
Full text
7
Montanari, Sara. "The effect of intervertebral disc simulated damage on the human spine biomechanics." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/19926/.
Full textAbstract:
More than 50% of intervertebral discs in the third and fourth decade of life exhibit annular tears and fissures with different orientations and extents. On the other hand, in vitro biomechanical investigations of the disc surgery treatment, sometimes requires collaterals lesions, such as incision or disc material removal to recreate biological injuries, as in discoplastly. These lesions could have a mechanical impact on the spine flexibility and in the surrounding tissue and could alter the final outcomes of in vitro studies.
The influence of the presence of lesions on the biomechanics of the segment is still a debated research question.
Thus, this in vitro study aims to evaluate changes in spine biomechanics, in terms of stiffness, range of motion and disc height, induced by an increasing damage of human disc. In order to assess the impact of the annulus damage on the surrounding tissues, principal strain distributions were investigated in the lateral side opposite than the damaged region.
Eight fresh cadaver thoraco-lumbar FSUs were used in this study. The specimens were tested sequentially in flexion and extension in five different configurations: a) with the intact disc; b) with two vertical cuts; c) with four cuts, forming a square, without removing any part of the annulus; d) after having removed the cut part of the AF; e) after having removed the nucleus pulposus. Image analysis and surface strain distribution were performed on the lateral disc by means of the Digital Image Correlation.
8
Parry, Joanna. "The comparison of different pathologies of the annulus fibrosus in human intervertebral disc." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342052.
Full text
9
Lakstins, Katherine S. "Investigating the human cartilage endplate in chronic low back pain: from mechanisms of degeneration to molecular, cell and tissue level characterization." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1584627459584403.
Full text
10
Stolworthy, Dean K. "Advancing Biomechanical Research Through a Camelid Model of the Human Lumbar Spine." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5590.
Full textAbstract:
The increasing incidence of disc degeneration and its correlation with lower back pain is an alarming trend in modern society. The research of intervertebral disc degeneration and low back pain would greatly benefit from additional methods to study its etiology and possible treatment methods. A large animal model that maintains the biological and mechanical environment that is most similar to the human lumbar spine could provide substantial improvements in understanding and resolving the problem of intervertebral disc related low back pain.This dissertation presents my doctoral work of investigating the potential for the camelid cervical spine to serve as a suitable animal model for advancing biomechanical research of low back pain and intervertebral disc degeneration in the human lumbar spine. Specifically, this work identifies the cellular, morphological and biomechanical characteristics of the camelid cervical spine and intervertebral disc as compared to the human lumbar spine. My results demonstrate that there are remarkable similarities in all aspects. Many of the similarities with respect to the cellular environment of the intervertebral disc are a consequence of the camelid status as a large mammal. Additional testing of the cellular makeup of the camelid intervertebral disc cells revealed that many human qRT-PCR primers associated with disc degeneration are suitable for use in alpacas without modification. From a biomechanics standpoint, the camelid cervical spine also has a vertically oriented spinal posture and is unsupported near the end in an open kinetic chain, providing a mechanical parallel with the human lumbar spine. The camelid cervical intervertebral disc size is closer to the human lumbar intervertebral disc than all other currently used animal models available for comparison in the literature. Average flexibility (range of motion) of a camelid spinal motion segment showed similarities in all modes of loading. Based on magnetic resonance imaging and radiologic grading of the intervertebral disc, almost 90% of elderly camelids exhibited advanced degeneration (Pfirrmann grade 3 or higher) in their cervical spine, and about half of aged camelids have developed severe degeneration (Pfirrmann grade 4 or higher) in at least one or more of their cervical segments, most commonly within the two lowest cervical segments (e.g. c6c7 and/or c7t1). Thus, while there remain differences, the remarkable similarities between the camelid and human spine strengthen the case for using camelids as a model for human disc degeneration, normal and pathological biomechanics and fluid transport, and potentially as a pre-clinical model for investigating the efficacy of novel spinal devices.
11
Wei, Ai-Qun Clinical School St George Hospital Faculty of Medicine UNSW. "Biological therapies for the restoration of degenerated intervertebral discs." Publisher:University of New South Wales. Clinical School - St George Hospital, 2008. http://handle.unsw.edu.au/1959.4/42968.
Full textAbstract:
Low back pain is a common cause of disability and work inability, often associated with intervertebral disc degeneration. The current understanding of disc degeneration is limited and none of the available treatments is entirely effective. The work described herein investigates potential strategies for the biological herapeutic restoration of disc degeneration. Firstly, an in vitro study to investigate the effects of BMP-7 on human discal cellular viability was performed. Cultured cells were treated with TNF-a or H202 to induce apoptosis, resulting in the down regulation of extracellular matrix proteins, decreased cell viability, morphological changes and activation of caspase-3; however, addition of BMP-7 alone prevented the observed effects, demonstrating the ability of BMP-7 to prevent apoptosis of human disc cells in vitro. Secondly, the differentiation potential of stem cells towards disc-like cells was studied. Rodent mesenchymal stem cells (rMSCs) were cultured alone or co-cultured with rat disc tissue. Differentiation potential of rMSCs was evaluated by mRNA and protein expression, cellular function and morphological studies. The co-culture conditions led to the expression of chondrocytic markers in rMSCs, whereas rMSCs cultured alone did not express the chondrocytic markers. Cellular contact between the co-cultured rMSCs and the discal tissue were observed. This study demonstrated that rMSCs can differentiate into functional disc-like cells in a tissue influenced co-culture environment. Finally, the survival and differentiation of CD34+ or CD34?? bone marrow (hBM) cells, in an intra-discal xenogeneic transplantation rat model was investigated. Human CD34+ or CD34?? cells were isolated, fluorescent-labelled and injected into rat coccygeal discs. The survival of transplanted cells was confirmed by fluorescent positive cells as well as a human nuclear specific marker. Interestingly, CD34?? cells survived until day 42 in the injected discs, and differentiated into cells ex:pressing a chondrocytic phenotype. In contrast, CD34+ cells could not be detected by day 21. This data suggests that transplanted hBM CD34?? cells, in contrast to CD34+ cells, were able to survive and differentiate within the intervertebral disc. Together, the results of these studies can both encourage and contribute to the basis of potential biological therapies in the restoration of intervertebral disc degeneration.
12
Massey, Christopher John Marcolongo Michele S. "Finite element analysis and materials characterization of changes due to aging and degeneration of the human intervertebral disc /." Philadelphia, Pa. : Drexel University, 2009. http://hdl.handle.net/1860/3128.
Full text
13
Joshi, Abhijeet Bhaskar. "Mechanical behavior of the human lumbar intervertebral disc with polymeric hydrogel nucleus implant : an experimental and finite element study /." Philadelphia, Pa. : Drexel University, 2004. http://dspace.library.drexel.edu/handle/1860/272.
Full text
14
Gilbert, Hamish. "The response of human annulus fibrosus cells to cyclic tensile strain : evidence for an altered mechanotransduction pathway with intervertebral disc degeneration." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/the-response-of-human-annulus-fibrosus-cells-to-cyclic-tensile-strain-evidence-for-an-altered-mechanotransduction-pathway-with-intervertebral-disc-degeneration(e61ab359-7b23-454e-ab4b-2236d3ea9ed9).html.
Full textAbstract:
The Intervertebral disc (IVD), comprised of two distinct regions, namely the fibrous annulus fibrosus (AF) and the gelatinous nucleus pulposus (NP), is a fibrocartilage pad located between adjoining vertebrae of the spine. The function of the IVD is to provide stability to the spine, while maintaining movement. IVD degeneration, also known as degenerative disc disease (DDD), is the process whereby the IVD tissue degrades, resulting in loss of function to the disc. Low back pain (LBP) is associated with the degeneration of the IVD, making it important to investigate the pathogenesis of DDD, as this could lead to novel therapies for the prevention and/or treatment of LBP. Mechanical stimuli (MS) are known to be important for IVD cell matrix homeostasis, with cells of the AF and NP responding to physiological forces with a trend towards increased matrix anabolism, while non-physiological forces lead to matrix catabolism. Furthermore, recent evidence suggests that IVD cells derived from degenerate tissue may have lost their ability to respond to physiological MS in the 'normal' anabolic manner, potentially leading to the progression of DDD. It is therefore important to investigate the response of IVD cells derived from both non-degenerate and degenerate tissue to MS, to ascertain whether there is a difference with degeneration. If the response is found to be altered with degeneration, then elucidation of the potentially altered mechanotransduction pathway utilised by degenerate cells could lead to the discovery of novel therapeutic targets for the treatment of DDD. To date, the majority of IVD MS studies have concentrated on the response of NP cells to hydrostatic pressure, with only a limited number of AF studies available. Thus, the first aim of this PhD was to investigate the response of human AF cells derived from non-degenerate and degenerate IVDs to the physiologically relevant mechanical stimulus of cyclic tensile strain (CTS), to ascertain whether the response (regulation of matrix protein and matrix degrading enzyme gene expression) was frequency-dependent or altered with IVD degeneration. Using an in vitro mechanical loading system (Flexcell® Tension Plus™ system, Flexcell International) capable of delivering a CTS of 10% strain, 0.33Hz or 1.0Hz for 20 minutes, the response of AF cells derived from non-degenerate IVDs was found to be frequency-dependent (reduced catabolism at 1.0Hz, with decreased MMP -3 and ADAM-TS -4 gene expression; and catabolic at 0.33Hz, with decreased types I and II collagen and increased MMP -9 gene expression). Furthermore, the response of AF cells to 1.0Hz CTS was shown to be altered with IVD degeneration, depicted by a switch from reduced catabolism (decreased MMP -3 and ADAM-TS -4) in non-degenerate AF cells, to reduced anabolism (decreased aggrecan and type I collagen gene expression) in degenerate AF cells. Subsequently, the second aim of the PhD was to attempt to elucidate the mechanotransduction pathways operating in human AF cells derived from non-degenerate and degenerate IVDs, to ascertain whether the mechanotransduction pathway was altered with IVD degeneration. An identical mechanical stimulation regime was used (1.0Hz CTS) in parallel with functional inhibitors against the cytokines interleukin (IL) -1 and -4, and the cell surface receptors, RGD-recognising integrins. Additionally, the involvement of the cytokine associated transcription factors, nuclear factor kappa beta (NFκB) and signal transducer and activator of transcription (STAT) -6, as well as the integrin-associated kinase, focal adhesion kinase (FAK) was investigated in 1.0Hz CTS-treated non-degenerate AF cells. The response to 1.0Hz CTS (reduced catabolism) of AF cells derived from non-degenerate IVDs occurred in an IL -1, IL -4 and RGD-recognising integrin-dependent manner, with FAK being phosphorylated. Of significant interest, the altered response of AF cells derived from degenerate IVDs to 1.0Hz CTS (reduced anabolism) occurred independently of either cytokine and independently of RGD-recognising integrins, suggesting an altered mechanotransduction pathway in operation and warranting further investigation.
15
Strassburg, Sandra. "An In Vitro Culture System to Study Human Mesenchymal Stem Cell / Nucleus Pulposus Cell Interactions : Implications for Intervertebral Disc Regeneration." Thesis, University of Manchester, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521587.
Full text
16
Rodrigues, Pinto Ricardo Pedro Ferreira. "Isolation and phenotypic characterisation of human notochordal cells : implications for the development of cell-based therapies for intervertebral disc degeneration." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/isolation-and-phenotypic-characterisation-of-human-notochordal-cells-implications-for-the-development-of-cellbased-therapies-for-intervertebral-disc-degeneration(8d5cbfdd-edd0-458c-a048-554f6a2c830b).html.
Full textAbstract:
Back pain is a highly prevalent condition whose pathogenesis is associated with intervertebral disc (IVD) degeneration. Degeneration is driven by abnormal cell biology, particularly within the IVD’s inner core, the nucleus pulposus (NP). In recent years, there has been an ever-increasing search for cell-based therapies aimed at correcting the cell biology and thus repairing/regenerating the degenerate IVD. The success of these novel therapies, however, requires a thorough understanding of IVD development and of the phenotype of its cells. The embryonic, foetal and juvenile NP is populated by large vacuolated notochordal cells that with skeletal maturity are replaced by smaller NP cells. Since notochordal cells have been shown to display protective and anabolic roles in the IVD their loss in humans has often been suggested to initiate the degenerative process. As such, a detailed understanding of notochordal cells and their regulatory pathways may help identify factors involved in IVD homeostasis and aid the development of novel cell-based therapies targeting IVD degeneration. The study of human notochordal cells has, however, been hindered by ethical, logistical and technical difficulties in obtaining suitable samples and, as such, the human notochordal cell phenotype is, to date, unknown, constituting a major limitation in the field. The work presented here was conducted with the objective of developing a methodology to isolate human developing notochordal cells (NP progenitors) from adjacent sclerotomal cells (annulus fibrosus and vertebral body progenitors), to characterise the notochordal cell phenotype and identify potential factors involved in notochordal cell biology. Initially, human embryonic and foetal spines were characterised to assess their suitability as a source of notochordal cells and to identify a notochord-specific marker that could be used to isolate notochordal cells for microarray studies. The human developing spine contained large vacuolated notochordal cells in all stages analysed (3.5-18 weeks post-conception (WPC)) that specifically expressed KRT8, KRT18 and KRT19 at all stages and CD24 between 5.5-18 WPC. KRT18 and CD24 were independently used to label notochordal cells (7.5-14 weeks post-conception) and separate them from sclerotomal cells. Methodologies were developed to allow extraction of RNA of sufficient quality for microarray analysis from fixed, permeabilised (in the case of KRT18) and/or, labelled and sorted cells (CD24). Microarray analysis identified and real-time qPCR and, for some markers, immunohistochemistry, validated GRB14, SLC19A1, FGF10, ADORA3, TBXA2R, CDH6, ANPEP, CD69, CD24, RTN1, PRPH, MAP1B, ISL1 and CLDN1 as human notochordal cell markers. Ingenuity pathway analysis was performed to investigate the pathways/networks and upstream regulators and downstream effectors of notochordal cells. Inhibition of inflammation and angiogenesis were identified as relevant to notochordal cell biology, function and, possibly, to the known protective and anabolic role notochordal cells display in the IVD. Notochordal marker gene expression was identified in adult NP tissue, and negatively correlated with degeneration. Proteins encoded by ADORA3 and MAP1B were expressed by a proportion of adult NP cells, suggesting the presence of notochord-derived cells in the adult NP.Importantly, this is the first study to detail a methodology and successfully isolate human notochordal cells. Such methodology has the potential to be used to culture and investigate the biology of viable human notochordal cells (CD24+ve). Future studies aimed at developing cell-based therapies for IVD degeneration could also use these identified markers to assess appropriate stem cell differentiation to notochordal cells.
17
Paassilta, P. (Petteri). "The human COL9A3 gene:structure of the gene for the α3 chain of type IX collagen and its role in human cartilage and intervertebral disc diseases." Doctoral thesis, University of Oulu, 1999. http://urn.fi/urn:isbn:9514254562.
Full textAbstract:
Abstract
The nucleotide sequence of the entire COL9A3 gene, coding
for the human α3(IX) chain, was determined. The gene was
approximately 23 kb in length and consisted of 32 exons. The polymerase chain
reaction (PCR)-based procedure of conformation-sensitive gel electrophoresis
(CSGE) was used to screen the gene for sequence variations and mutations
in 83 unrelated patients with generalized primary osteoarthritis
(OA), 31 with rheumatoid arthritis (RA), 171 with intervertebral disc
disease (IDD), and 50 with various osteochondrodysplasias. The frequencies
of certain sequence variations in healthy individuals were also
determined.
The COL9A3 gene was analyzed for mutations in two unrelated
families with multiple epiphyseal dysplasia (MED). The analysis
revealed a splice site mutation leading to skipping of exon 3 and
an in-frame loss of 12 amino acid residues in the COL3 domain, the
first diseasecausing mutation to be identified in the COL9A3 gene.
Sequencing also indicated a 9 bp deletion in one allele in the second MED
family that removed a Gly-Pro-Pro triplet. Surprisingly, the deletion
did not co-segregate with the MED phenotype in the family. A similar
9 bp deletion, was also found in an unrelated family with no obvious
phenotype, suggesting that the two 9 bp deletions represent neutral
sequence variants. A construct with the deletion was then made in
order to produce a recombinant protein, and the mutant type IX collagen
was analyzed under reducing conditions by SDS-PAGE. The results
indicated that the recombinant type IX collagen proteins consisted
of three α chains, α1(IX), α2(JX), α3(IX),
in a 1:1:1 ratio. To study the triple helix stability, pepsin treatment
followed by SDS-PAGE was performed on normally folded and denatured
recombinant type IX collagen samples. The results demonstrated that
the recombinant type IX collagen containing the Gly-X-Y deletion
in the a3(IX) chain is secreted as a correctly folded triple-helical
molecule.
CSGE analysis of exon 5 of the COL9A3 gene identified two
nucleotide variations in the same codon, and thus three alleles:
CGG (Arg), CAG (Gln), and TGG (Trp). The frequency of the Trp for Arg
substitution, the Trp3 allele, was 0.244 among the probands with
the IDD, while its overall frequency in the combined group of all
non-IDD cases was 0.093. This difference was significant, with a
p-value of 0.000013. The Trp3 allele increases the relative risk
of IDD by a factor of 2.6 (95 percent confidence interval, 1.6 to
4.3).
COL9A3 mutations are shown to be associated with mild cartilage
and intervertebral disc diseases.
18
Esat, Volkan. "Biomechanical modelling of the whole human spine for dynamic analysis." Thesis, Loughborough University, 2006. https://dspace.lboro.ac.uk/2134/7839.
Full textAbstract:
Developing computational models of the human spine has been a hot topic in biornechanical research for a couple of decades in order to have an understanding of the behaviour of the whole spine and the individual spinal parts under various loading conditions. The objectives of this thesis are to develop a biofidefic multi-body model of the whole human spine especially for dynamic analysis of impact situations, such as frontal impact in a car crash, and to generate finite element (FE) models of the specific spinal parts to investigate causes of injury of the spinal components. As a proposed approach, the predictions of the multi-body model under dynamic impact loading conditions, such as reaction forces at lumbar motion segments, were utilised not only to have a better understanding of the gross kinetics and kinematics of the human spine, but also to constitute the boundary conditions for the finite element models of the selected spinal components. This novel approach provides a versatile, cost effective and powerful tool to analyse the behaviour of the spine under various loading conditions which in turn helps to develop a better understanding of injury mechanisms.
19
Pang, Toh Yen, and tohyen_pang@yahoo com. "The transmission of vibration at the lower lumbar spine due to whole-body vibration: a numerical human model study." RMIT University. Aerospace Mechanical and Manufacturing Engineering, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20060825.160144.
Full textAbstract:
Lower back disorders due to whole-body vibration (WBV) are the most common injuries reported by professional drivers. Such injuries often have long-term complications leading to significant personal and societal costs. An improved mathematical model of the whole human body would contribute to a better understanding of the mechanisms of lower back injury and be valuable in injury prevention research. Current biodynamic human models reported in the literature lack detailed information for predicting the non-linearity due to vibration amplitude of transmission of vibration from seat to a human. Therefore, one of the primary objectives of this research has been to develop and validate a detailed threedimensional biodynamic human model, with special attention given to the incorporation of active trunk muscles with non-linear stiffness properties. These muscles have been incorporated into an existing spine and neck model of a MADYMO 50th percentile male occupant model. A detailed multi-body human model has been developed, called MODEL ONE. This thesis shows that incorporating non-linear stiffness functions and energy dissipation using hysteresis or damping into a human model is appropriate for predicting non-linear biodynamic responses in arbitrary excitation functions. A major advantage of MODEL ONE compared to other multi-body models and lumped mass models is its ability to predict nonlinear seat-to-human transmissibility. However MADYMO 50th male occupant models use simplified geometry and rigid bodies to represent the lower lumbar spine. These simplified spinal models have no ability to simulate the internal stresses and deformations of soft tissues, even if these are the apparent cause of lower back pain (LBP). Therefore a detailed finite element human lower lumbar spine model - with appropriate material properties and capable of simulating internal stresses⎯is necessary, in order to better understand spinal injuries under WBV. A three-dimensional finite element model of a lower lumbar spine motion segment - called MODEL TWO - has thus been developed for the present study. MODEL TWO comprises a detailed geometric description of vertebrae, nucleus pulposus, endplates, and intervertebral discs. The intervertebral discs lump together the annulus fibrosus, ground substance and ligaments. The vertebrae have been assumed to be rigid. The material properties of the intervertebral discs of MODEL TWO were obtained from test matrices and from various parameter data reported in the literature. MODEL TWO has been validated against cadaveric experiments reported in the literature. The mechanical behaviour and stress distribution within the MODEL TWO intervertebral disc agree reasonably well with the cadaveric experiments. MODEL TWO was integrated into MODEL ONE to form a new human model, called MODEL THREE, which was subsequently dynamically validated against volunteers� responses to WBV reported in the literature. MODEL THREE, as presented in this thesis, consists of a multi-body human model with detailed representation of a finite element (FE) lower lumbar spine. As far as the author is aware, MODEL THREE is the first model with detailed representation of a FE lower lumbar spine to successfully demonstrate that it is capable of simulating the stress profile of the entire intervertebral disc and endplate region due to WBV. The simulated results revealed abnormal stress concentrations in both the posterior and xviii the posterolateral annulus. The stresses increased most in the posterolateral intervertebral discs region during WBV, suggesting a possible mechanism for disc mechanical overload leading to fatigue fracture and degeneration. The results from MODEL THREE are promising and lead to a more comprehensive understanding of the behaviour of the intervertebral disc under WBV. MODEL THREE has also provided a good foundation for the development of a bio-fidelity human model. However, implementation of currently unavailable and/or inadequate in vitro and in vivo experimental studies is needed to further validate and develop MODEL THREE. A better understanding of injury mechanisms and the clinical significance of LBP will ultimately be arrived at using a combination of analytical models with in vitro and in vivo experimental data.
20
Aladin, Kaderbatcha Darwesh Mohideen. "A macro, nano level study to evaluate the impact of Trp2 allele in the [alpha] 2 chain of collagen IX on the biomechanics of human intervertebral discs and disc collagens." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B39634425.
Full text
21
Prado, César Vinicius Gil Braz do. "Combination of stem cells from deciduous teeth and electroacupuncture in dogs with chronic spinal cord injury." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/10/10132/tde-21032017-162328/.
Full textAbstract:
Previous studies have reported that combination of electroacupuncture (EA) and mesenchymal stem/stromal cells (MSC) promoted survival, differentiation and functional recovery in spinal cord-transected rats. In this study, it was examined the therapeutic effects of stem cells from canine exfoliated dental pulp (SCED) combined with EA treatment in dogs with chronic naturally occurred spinal cord injury due to intervertebral disc herniation (IVDH). Dogs were randomly assigned to four experimental groups (n=4 for each group; total of 16 animals): SCED, EA, SCED + EA) and control. Mild increase in the neurological scoring was found in one animal from SCED group (1/4; 2 points gained), one from EA group (1/4; 8 points gained), three from SCED+EA group (3/4; 16 points gained) and one from control group (1/4; 2 points gained). Functional outcome improvements were observed two animals from SCED group (2/4; 3 points gained), two from EA group (2/4; 4 points gained), one from SCED+EA group (1/4; 1 point gained) and two were from control group (2/4; 6 points gained). However no statistical differences were observed. Magnetic resonance imaging (MRI) findings did not suggest improvement comparing pre- and post-treatment within groups, excepted from one animal from SCED group (1/4), and 10 animals from all groups (10/16) presented signs of injury progression in the SCI in post-treatment exam, which could not be associated to the procedures from study, but could be related to the natural evolution of the disease. Limitation such as number of transplanted stem cells, delivery route, injury chronicity and intrinsic variation among naturally spinal cord injured dogs could have influence outcomes negatively. Moreover, canine deciduous exfoliated teeth were easily obtained and SCED were simply isolated, and no mortality followed up 7 month from procedure were observed.Estudos anteriores demonstraram que a associação da eletroacupuntura e células-tronco mesenquimais/estromais (CTMs) pode promover a sobrevivência e diferenciação das CTMs, assim como recuperação funcional em ratos com transecção da medula espinal. Neste estudo, foram avaliados os efeitos terapêuticos da associação de células-tronco derivadas de polpa de dente decíduo esfoliado de cães (CPDEc) e eletroacupuntura (EAP) em cães com lesão de medula espinhal crônica causada de forma natural por herniação do disco interververtebral. Os cães foram divididos aleatoriamente em quatro grupos experimentais (n=4 para cada grupo; total de 16 animais): CPDEc, EAP, CPDEc+EAP e grupo controle. Foram encontradas pequenas melhoras na pontuação do exame neurológico em um animal do grupo CPDEc (1/4; 2 pontos ganhos), um do grupo EAP (1/4; 8 pontos ganhos), três do grupo CPDEc+EAP (3/4; 16 pontos ganhos) e um do grupo controle (1/4; 2 pontos ganhos). Na avaliação funcional, pequenas melhoras também foram observadas em dois animais do grupo CPDEc (2/4; 3 pontos ganhos), dois do grupo EAP (2/3; 4 pontos ganhos), um do grupo CPDEc+EAP (1/4; 1 ponto ganho) e dois do grupo controle (2/4; 6 pontos ganhos). No entanto, não foram encontradas diferenças estatísticas entre os grupos. Os achados ressonância magnética não sugeriram melhoras comparando os exames pré e pós tratamento entre os grupos, com exceção de um animal do grupo CPDEc (1/4), e 10 animais dentre todos os grupos (10/16) apresentaram sinais de progressão na lesão da medula espinhal, que não puderam ser associados com os procedimentos do estudo, mas podem estar relacionados à progressão natural da doença. Além disso, os dentes decíduos esfoliados foram obtidos facilmente e as CPDEc foram isoladas de forma simples, ademais, não foi observada nenhuma mortalidade foi observada até 7 meses após o procedimento.
22
Côrte-Real, João Vasco de Almeida Pessanha. "Establishment of a human model of intervertebral disc degeneration and associated immune response." Dissertação, 2018. https://hdl.handle.net/10216/118623.
Full text
23
Côrte-Real, João Vasco de Almeida Pessanha. "Establishment of a human model of intervertebral disc degeneration and associated immune response." Master's thesis, 2018. https://hdl.handle.net/10216/118623.
Full text
24
Tseng, Wen-Li, and 曾雯莉. "The Failure Strength and Patterns of Human Degenerated Intervertebral Disc in Resisting the Hydrostatic Pressure." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/38341412961618740302.
Full textAbstract:
碩士國立臺灣大學
醫學工程學研究所
96
Objective： To evaluate the strength of hydrostatic pressure of endplate and the spreading pattern of contrast agent in the disc. Summary of Background Data： One of the disc degeneration therapies is to inject the biomaterials, which replace or promote regeneration of nucleus into the nucleus pulposus. To determine the efficacy of this therapy and the criteria of patient selection, it is important to evaluate the hydrostatic pressure strength of endplate and the injection pattern of contrast agent in the disc. Methods：Fifteen discs from 5 cadaver thoracic and lumbar spines (aged 77-92 years, mean age: 86 years) were injected with contrast agent using the quantitative discomanometry (QD) apparatus. The injection process was scanned with cine-CT. The endplate leakage pressure, spreading pattern of contrast agent in the disc, and the correlation between leakage pressure and bone mineral density (BMD) were analyzed. To observe the grade of endplate degeneration and the leakage site of the contrast agent, the discs were sectioned along the coronal plane, and macroscopic photographed. Result：The center region of endplate (1.03±0.14mm) was the thinner than the one of periphery region (1.26±0.06mm). Spreading patterns of contrast agent in the disc included “nucleus space expansion” and “anular fissure formation”. The contrast agent was found to leak through the endplate and the anulus fibrosis. The endplate leakage pressure (0.18±0.17MPa) was lower than the anular leakage pressure (0.27±0.21MPa). The endplate and anular leakage pressure were found positively correlated with BMD. Comparing CT images to macroscopic photographies, the contrast agent leaked through the fissure and the sclerosis site of endplate. The discontinuous lines between endplate and disc in CT images may be the indication of endplate degeneration. Conclusion：Both of the endplate leakage pressure and the anular leakage pressure were correlated positively with BMD. The contrast agent spread through the anular fissure of disc, and leaked through the fissures and the sclerosis site of endplate.
25
Smith, Lachlan James. "Structure and function of the elastic fibre network of the human lumbar anulus fibrosus." 2008. http://hdl.handle.net/2440/47917.
Full textAbstract:
Degeneration of the lumbar intervertebral disc, a condition widely implicated in the cause of low back pain among adult humans, is typically characterised by progressive biochemical and structural changes to the extracellular matrix. Comprehensive descriptions of the structural and functional inter-relationships within the extracellular matrix are therefore critical to understanding the degenerative process and developing effective treatments. In the anulus fibrosus, this matrix has a complex, hierarchical architecture comprised of collagens, proteoglycans, and elastic fibres. Elastic fibres are critical constituents of dynamic biological structures that functionally require elasticity and resilience. Studies to date of elastic fibre network structure in the anulus fibrosus have been qualitative and limited in scope. Additionally, there is poor understanding of the structural and functional associations between elastic fibres and other matrix constituents such as collagen, and, critically, there have been no studies directly examining the nature and magnitude of the contribution made by elastic fibres to anulus fibrosus mechanical behaviour. In this thesis, multiple experimental studies are described that specifically examine each of these areas. Novel imaging techniques were developed and combined with histochemistry and light microscopy to facilitate the visualisation of elastic fibres at a level of detail not previously achieved. Examination of elastic fibre network structure revealed architectural differences between the intralamellar and interlamellar regions, suggesting that elastic fibres perform functional roles at distinct levels of the anulus fibrosus structural hierarchy. The density of elastic fibres within lamellae was found to be significantly higher in the lamellae of the posterolateral region of the anulus than the anterolateral, and significantly higher in the outer regions than the inner, suggesting it may be commensurate with the magnitude of the tensile strains experienced by each region of the disc in bending and torsion. The nature of the structure-function associations between elastic fibres and collagen was then examined with respect to the reported structural mechanisms of collagen matrix tensile deformation. Histological assessment of collagen crimp morphology in specimens from which elastic fibres had been enzymatically removed revealed no observable differences when compared with controls, suggesting that any contribution made by elastic fibres to maintaining crimp is minimal. Elastic fibres in anulus fibrosus specimens subjected to radial tensile deformations exhibited complex patterns of re-arrangement, suggesting that they maintain cross-collagen fibre connectivity. Elastic fibres were also observed to maintain physical connections between consecutive lamellae undergoing relative separation. Finally, the nature and magnitude of the contribution made by elastic fibres to anulus fibrosus mechanical properties at the tissue level was investigated using a combination of biochemically verified enzymatic treatments and biomechanical tests. Targeted degradation of elastic fibres resulted in a significant reduction in both the initial modulus and the ultimate modulus, and a significant increase in the extensibility, of radially oriented anulus fibrosus specimens. Separate treatments and mechanical tests were used to account for any changes attributable to non-specific degradation of glycosaminoglycans. These results suggest that elastic fibres enhance the mechanical integrity of the anulus fibrosus extracellular matrix in the direction perpendicular to the plane containing the collagen fibres. In summary, the results of the studies presented in this thesis provide important new insights into the structure and function of the anulus fibrosus elastic fibre network, and highlight its potential importance as a contributing or ameliorating factor in the progression of the structural and mechanical changes associated with intervertebral disc degeneration. Additionally, these results establish an improved framework for the development of more accurate analytical and finite element models to describe disc behaviour.http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1317006
Thesis (Ph.D.) -- University of Adelaide, School of Medical Sciences, 2008
26
Liao, Shao-Yu, and 廖紹妤. "Applications of Low-intensity Pulsed Ultrasound Stimulation on Human Annular Fibrosus Regeneration for Intervertebral Disc Degenerative Disease." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/69486434387688660369.
Full textAbstract:
碩士國立陽明大學
醫學工程研究所
100
The low intensity plus ultrasound (LIPUS) is forms of physical stimulations, ultrasound have been found to be effective non-invasive treatments for bone healing and tissue repair in clinical. Despite the efficacy exhibited in clinical application, molecular evidence of ultrasound therapeutic effects and biochemical mechanisms on intervertebral disc remain limited. The therapeutic effects of ultrasound could be explained by a propagation of acoustic waves that transfers mechanical energy into tissues. The mechanical forces could serve as extracellular information, which may induce certain intracellular signaling pathway and regulate cell growth, function and differentiation. In this study, the aim is elucidate the effects of physical stimulations on annulus fibrosus cells (AF) mechanotransduction and regulation of extracellular matrix metabolisn in vitro. First, we investigate the effects of ultrasound on cultured AF cell and the molecular and biochemical mechanisms by which ultrasound promote AF cell proliferation and regulate extracellular matrix metabolism. Next, we investigate mechanotransduction pathways of AF cell, and crosstalk mechanisms between transforming growth factor-β (TGF-β) and ultrasound stimulation during mechanotransduction. In this study, the best parameters of ultrasound was treat by 0.5W/cm2 for 5 min for 5 days. The result shows that the cell viability and total GAGs contents has significantly enhanced after treatment, and, the transforming growth factor beta1 (TGF-β1) also activited . Therefore, the synthesis of collagen type I content was increased, otherwise, matrix metalloproteinase-1 (MMP-1) and matrix metalloproteinase-13 (MMP-13) decreased. Furthermore, ultrasound induces Extracellular signal-regulated kinases (ERK) pathway, which doesn’t relate on cell viability. This study revealed that ultrasound stimulation regulates extracellular matrix metabolism through the crosstalk between TGF-β and ultrasound-induced mitogen-activated protein kinases (MAPKs) signaling pathways. Physical stimulus induced the synthesis and release of transformation growth factor-β1, which plays an important role in the synthesis of extracellular matrix catabolism, and the present experimental results show that ultrasound stimulation can indeed enhance the repair of the annulus fibrosus cells.
27
Wu, Guan-De, and 吳冠德. "The Biomechanical and Biochemical Analyses of Human Lumbar Degenerated Intervertebral Disc with and without Exogenous Crosslinking Treatment." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/6h8nfa.
Full textAbstract:
碩士國立臺北科技大學
機電整合研究所
105
Degenerative disc disease (DDD) is a common disease in middle-aged and elderly people. When disc degeneration becomes severe, it can be treated with invasive surgery. When the intervertebral disc is partially removed for decompression surgery or replaced with implants. Such surgical interventions may change the spinal load-bearing mechanism, cause adjacent level compensation, and accelerate the adjacent disc degeneration. Upon the progress of medical knowledge and engineering technology, the implants used to replace the intervertebral disc structure, such as artificial nucleus pulposus and artificial intervertebral disc have been developed using biomimetic concepts and preserving more original tissues. The aim of this research is to investigate the effects of Genipin crosslinking on the biomechanical and biochemical changes on human intervertebral disc tissues. At first, we will collect disc tissue samples from patients who will undergo lumbar fusion surgeries for treating degenerative disc diseases, either with herniated intervertebral disc (HIVD), or lumbar spondylolisthesis. The level of degeneration is categorized by using magnetic resonance imaging (MRI) data. The nucleus pulposus tissue samples harvested from patients were divided into control group, experiment group and crosslinking group in order to perform the mechanical testing and biochemical composition analysis, respectively. Before the mechanical testing can be performed, the testing fixture for creep test was designed and used to carry out the experiment after verification using porcine annulus fibrosus. The data from the human disc tissue creep test will be substituted into a biphasic mathematical model to obtain the biphasic material property (HA and K0). The analysis of biochemical composition can be further divided into water content, collagen content, and glycosaminoglycans(GAG) content tests. The results showed that the deformation and permeability will decrease and the aggregate modulus (HA) will increase by the degeneration of the nucleus pulposus in the human body after the cross-linking of exogenous genipin, which means that the extracellular matrix structure becomes denser as well as improving the static stiffness of the tissue (resistance to external load and energy storage). We can discover that the accumulation will increase and the increased tissue stiffness will make the tissue more susceptible to damage as the degeneration level becomes higher (such as, level V). It means that the tissue sclerosis becomes severe and makes the tissue lose tenacity and swelling ability. Those results can be obtained from the decrease of creeping displacement and increase of aggregate modulus. After biochemical composition analysis, the control group was found to have no significant difference from the experiment group in water content. Water content can be decreased gradually from grade III to V degradation; the permeability will decrease after crosslinking and nutrient will be remained inside the tissue which reduces the discharge. The content of collagen and GAG dissolved from tissue was decreasing obviously. It means that the extracellular matrix was denser after crosslinking, so that the tiny molecular structure is blocked inside the tissue. This research confirmed that Genipin exogenous crosslinking can effectively improve the mechanical properties, biological composition and other characteristics of the degenerated human disc tissues. Since the test specimens used in the current study were directly obtained from human discs, the results can provide more direct response of the human physiological situations.
28
Bridgen, Devin. "Regulation of Human Nucleus Pulposus Cell Phenotype and Behavior by Laminin-Mimetic Peptide Substrates." Diss., 2015. http://hdl.handle.net/10161/10513.
Full textAbstract:
Intervertebral disc (IVD) disorders can cause pain and disability for affected individuals. A subset of IVD disorders are thought to originate in the nucleus pulposus (NP) region of the IVD, due to alterations in tissue structure and composition with age and injury. Cells of the NP undergo a phenotypic and behavioral shift with age, changes that are thought to disrupt tissue homeostasis and lead to disc degeneration. There is significant interest in developing biomaterials and strategies to revert adult degenerate NP cells to healthy, young NP cell phenotypes with increased biosynthesis and cell clustering. Studies demonstrate that healthy porcine NP cells interact with laminin proteins through specific integrin subunits on soft substrates in a process that regulates cell morphology and biosynthesis. The central hypothesis of this dissertation is that the engagement of cell-surface adhesion receptors, using laminin-mimetic peptides on a controlled stiffness material, can revert adult degenerate NP cellular phenotype and behaviors to their healthy, biosynthetically active form.
In the first part of this dissertation, integrin subunits used by adult degenerate human NP cells to attach to laminin were revealed using flow cytometric analyses, function blocking antibodies, and immunohistochemistry. Secondly, NP cell recognition peptides were identified by screening laminin-mimetic peptides for cell attachment. Finally, human NP cells were cultured on peptide functionalized polyacrylamide gels to examine the effect of ligand and substrate stiffness in regulating adult human NP cell phenotype and biosynthesis.
Findings reveal that adult human NP cells express and utilize integrin subunits α3, α5, and β1 to attach to laminins, in contrast to integrin α6β1 found previously for healthy porcine NP cells. This difference between current and previous findings likely arises from aging-associated difference in NP cells between human and porcine tissues. Select laminin-mimetic peptides, chosen from the literature and informed by NP cell integrin expression, were found to promote significant NP cell attachment in a concentration dependent manner. Finally, a subset of laminin mimetic peptides were found to promote a young NP cell phenotype by increasing cell clustering on soft (0.3 kPa) and stiff (14 kPa) substrates as well as increasing proteoglycan synthesis on soft substrates.
The studies presented in this dissertation demonstrate that adult degenerate human NP cells attach to laminin proteins in an integrin dependent manner. Furthermore, laminin-mimetic peptides are able to mediate human NP cell attachment at levels comparable to full-length laminin, increase cell clustering when presented on soft and stiff substrates, and can increase NP cell biosynthesis when presented on soft substrates. Utilizing laminin-mimetic peptides may allow for the design of biomaterials that promote a healthy young NP phenotype for a variety of disc therapies.
Dissertation
29
Matos, Joana Filipa Ferreira de. "Development of a 3D multibody system of the human lumbar spine." Master's thesis, 2013. http://hdl.handle.net/1822/27704.
Full textAbstract:
Dissertação de mestrado integrado em Engenharia BiomédicaIn the present work, a three-dimensional multibody model of the lumbar spine was developed to analyse the force and torques that each intervertebral disc (IVD) is subjected during daily movements. The first work’s stage summarizes the literature review of the state-of-the-art of the multibody models of the spine. It was also characterized the anatomy of the spine, detailing at the vertebrae of the lumbar spine and sacrum, the facet joints, the intervertebral disc and the ligaments. The model is composed by five intervertebral discs, six vertebrae (L1 to S1), ligaments and facet joints. The vertebrae were simulated as rigid bodies, the intervertebral discs as bushing elements (with six degree-of-freedom), the ligaments as spring elements and the facet joints as separators. The spring constant of the bushing elements were characterized using data from a Finite Elements dedicated software, developed under the research project in which this work is inserted. To characterize the spring constant of the ligaments a curve of force-deformation found in the literature was used. After the model validation (with data found in the literature), it was possible to see how the force/torque is distributed along the intervertebral discs during several simulated movements: flexion, extension, lateral bending, axial rotation, traction and compression. Besides a healthy lumbar spine, it was also simulated a spine with fusion of L4L5 to calculate the percentage of variation of the force/torque that each IVD is subjected comparing with the healthy spine.
No presente trabalho, um sistema multibody tri-dimensional da coluna lombar foi desenvolvido com o objetivo de analisar as forças e momentos a que cada disco intervertebral está sujeito durante movimentos diários. A primeira etapa do trabalho consistiu no resumo do estado-de-arte dos modelos multibody da coluna vertebral. Também foi caracterizada a anatomia da coluna vertebra, detalhando as vértebras da coluna lombar e o sacro, as facetas, o disco intervertebral e os ligamentos. O modelo é composto por cinco discos intervertebrais, seis vértebras (L1 até S1), ligamentos e facetas. As vértebras foram simuladas como sendo corpos rígidos, os discos intervertebrais como sendo bushing elements (com seis graus-de-liberdade), os ligamentos como sendo mola e as facetas como sendo separadores. As constantes de mola dos bushing elements foram caracterizadas usando dados gerados por um método de elementos finitos dedicado, no âmbito do projecto mais vasto em que este trabalho está inserido. Para caracterizar a contante de mola dos ligamentos usou-se curvas de força-deformação encontradas na literatura. Depois da validação do modelo (com dados encontrados na literatura), usou-se este para analisar a forma como os esforços (forças e momentos) se distribuem ao longo dos discos intervertebrais durante os movimentos simulados: flexão, extensão, rotação lateral, rotação axial, compressão e tração. Além da coluna saudável, também foi simulada a coluna vertebral com fusão L4L5 para a calcular a percentagem da variação da força/momento a que cada disco intervertebral está sujeito comparativamente com a coluna saudável.