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Posterior lumbar spinal dynamic stabilisation devices are intended to relieve the pain of spinal segments while prolonging the lifespan of adjacent intervertebral discs. This study focuses on the design of such a device, one that has the correct stiffness to stabilise the spinal segment by the correct amount. An initial literature survey covers contemporary topics related to the lumbar spine. Included topics are lumbar anatomy and kinematics, pathology of degenerative disc disease and treatment thereof, other spinal disorders such as spondylolisthesis and spinal stenosis, as well as the complications associated with lumbar dynamic stabilisation. The influence of factors such as fatigue and wear, as well as the properties of appropriate biomaterials are considered when determining the basis of the device design and development. Stabilising the spinal segment begins with correct material selection and design. Various designs and biomaterials are evaluated for their stiffness values and other user requirements. The simplest design, a U-shaped spring composed of carbon fibre-reinforced poly-ether-ether-ketone (CFR-PEEK) and anchored by polyaxial titanium pedicle screws, satisfies the most critical user requirements. Acceptable stiffness is achieved, fatigue life of the material is excellent and the device is very imaging-friendly. Due to financial constraints, however, a simpler concept that is cheaper and easier to rapid prototype was chosen. This concept involves a construct primarily manufactured from the titanium alloy Ti6Al4V extra-low interstitial (ELI) and cobalt-chrome-molybdenum (CCM) alloys. The first rapid prototype was manufactured using an additive manufacturing process (3D-printing). The development of the device was performed in three main stages: design, verification and validation. The main goal of the design was to achieve an acceptable stiffness to limit the spinal segmental range of motion (ROM) by a determined amount. The device stiffness was verified through simple calculations. The first prototype’s stiffness was validated in force-displacement tests. Further validation, beyond the scope of this study, will include fatigue tests to validate the fatigue life of the production-ready device. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

Posterior lumbar spinal dynamic stabilisation devices are intended to relieve the pain of spinal segments while prolonging the lifespan of adjacent intervertebral discs. This study focuses on the design of such a device, one that has the correct stiffness to stabilise the spinal segment by the correct amount. An initial literature survey covers contemporary topics related to the lumbar spine. Included topics are lumbar anatomy and kinematics, pathology of degenerative disc disease and treatment thereof, other spinal disorders such as spondylolisthesis and spinal stenosis, as well as the complications associated with lumbar dynamic stabilisation. The influence of factors such as fatigue and wear, as well as the properties of appropriate biomaterials are considered when determining the basis of the device design and development. Stabilising the spinal segment begins with correct material selection and design. Various designs and biomaterials are evaluated for their stiffness values and other user requirements. The simplest design, a U-shaped spring composed of carbon fibre-reinforced poly-ether-ether-ketone (CFR-PEEK) and anchored by polyaxial titanium pedicle screws, satisfies the most critical user requirements. Acceptable stiffness is achieved, fatigue life of the material is excellent and the device is very imaging-friendly. Due to financial constraints, however, a simpler concept that is cheaper and easier to rapid prototype was chosen. This concept involves a construct primarily manufactured from the titanium alloy Ti6Al4V extra-low interstitial (ELI) and cobalt-chrome-molybdenum (CCM) alloys. The first rapid prototype was manufactured using an additive manufacturing process (3D-printing). The development of the device was performed in three main stages: design, verification and validation. The main goal of the design was to achieve an acceptable stiffness to limit the spinal segmental range of motion (ROM) by a determined amount. The device stiffness was verified through simple calculations. The first prototype’s stiffness was validated in force-displacement tests. Further validation, beyond the scope of this study, will include fatigue tests to validate the fatigue life of the production-ready device. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

Dissertation in partial compliance with requirements for the Masters Degree in Technology: Chiropractic, Durban University of Technology, 2010. / The aim of this study was establish if Leander versus Static traction was useful for the treatment of facet syndrome, a common type of mechanical lower back pain seen by chiropractors. Two groups of fifteen participants were chosen on the basis of the inclusion and exclusion criteria. The first objective was to determine if Static linear traction was effective for the treatment of lumbar facet syndrome in terms of subjective and objective findings. The second objective was to determine if Leander traction was effective for the treatment of lumbar facet syndrome in terms of subjective and objective clinical findings. Lastly the third objective was to compare the subjective and objective clinical findings for both groups. Design: A randomised, two group parallel controlled clinical trial was carried out between the two sample groups. Participants had to have had chronic lower back pain (> 3months). Thirty symptomatic volunteer participants between 25 and 55 were randomly divided into two equal groups – group A (Leander traction) received 5 treatments over a 2 week period. Similarly, group B (Static linear traction) also received 5 treatments over a 2 week period. Algometer readings, Numerical Pain Rating Scale (NRS101), Pain Severity Scale (PSS) and Oswestery Disabilty Index (ODI) were used as v assessment tools. Subjective and objective clinical findings were taken on the first and second visits (i.e. 48 hours) prior to treatment and immediately after treatment. Another set of subjective and objective readings were taken one week after the fifth treatment in order to gauge the long term effects of both treatments. No treatment was given on the sixth visit. Pressure tolerance measurements using an algometer were taken at the end ranges of motion in Kemp’s test and spinal extension. Outcome measures: SPSS version 15 (SPSS Inc., Chicago, Illinois, USA) was used for statistical analysis of data. A p value of <0.05 was considered as statistically significant. The two groups were compared at baseline in terms of demographics variables and location using Pearson’s chi square tests and ttests as appropriate. Intra-group comparisons were made between all time points. A significant time effect indicated successful treatment intervention. Inter-group comparisons were achieved using repeated measures ANOVA tests for each outcome measured separately. A significant time group interaction effect indicated a significant treatment effect. Profile plots were used to assess the trend and direction of the treatment effect. Results: The results of the study showed that Leander traction and Static linear traction were both effective for treating chronic lumbar facet syndrome and no statistically significant difference was found between subjective and objective clinical findings between the two groups.

M.Tech. / Purpose: To determine what effects flexion distraction will have on males with chronic lumbar facet syndrome, in reference to intersegmental range of motion and pain. Method: Thirty male participants with chronic lumbar facet syndrome received flexion distraction technique. The trail consisted of seven visits over two to three weeks. Treatment was performed on the first to sixth visit, readings and questionnaires were completed on the first, fourth and seventh visits. Data collection was concluded before treatment on the mentioned visits. Subjective data consisted of the Oswestry Disability Index (ODI) and the Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2). Objective data included global lumbar range of motion measurements using the Baseline Digital Inclinometer, and segmental lumbar range of motion by means of the Radiographical Midplane Angle method. Results: Objectively, clinical significance of the intersegmental lumbar range of motion increased from the L1/L2 to the L4/L5 level (2.2% - 17.7%), but showed no statistical significance. In relation to the maximal motion possible at these levels, the increase in motion escalated from 0.8% at the L1/L2 segment to 9.2% at the L4/L5 segment. The global lumbar range of motion showed clinical significant increase in all of the ranges except for extension, however statistical significance was found in right lateral flexion only (p = 0.045). The greatest increase in motion was observed in left lateral flexion (15.72%) and a decrease in extension (3.72%) was illustrated. Subjectively, the group showed statistical significant improvement in both the SF-MPQ-2 (p = 0.000) and ODI (p = 0.000). Clinical meaningful change was noted throughout the subjective data, which resultantly showed a 66% and a 67% change in pain respectively. Conclusion: Flexion distraction has shown to have clinical significant effects on segmental and thus global range of motion, and great clinical meaningful change in pain levels and pain perception. Thus specific segmental mobilisation does affect the segmental motion.

O sistema de fixação vertebral utilizando o parafuso pedicular é um dos métodos mais eficientes no tratamento de patologias da coluna vertebral. Quando o parafuso estiver submetido à força de arrancamento, ele gera tensões ao redor, principalmente próximo do canal medular, situação que pode ser analisada pela técnica da fotoelasticidade. O objetivo foi analisar as tensões internas geradas em modelos fotoelásticos de vértebras, utilizando diferentes medidas de parafusos do sistema de fixação vertebral, submetidos à força de arrancamento. Foi utilizado um modelo de vértebra lombar em material fotoelástico utilizando três medidas de diâmetros externos de parafusos pediculares (5, 6 e 7mm) do tipo USS1. As tensões internas ao redor do parafuso foram avaliadas em 18 pontos pré-determinados utilizando um polariscópio de transmissão plana. As regiões de maiores concentrações de tensões foram observadas entre o canal medular e as curvas do processo transverso. Nas comparações das médias das tensões cisalhantes entre os parafusos 5 e 7mm, e 6 e 7mm foram observadas diferenças estatísticas significativas, o que não ocorreu com os parafusos de 5 e 6mm onde não foram observadas diferenças estatisticamente significativas. Foi observado que as tensões internas são mais elevadas em áreas irregulares próximas do canal medular, o que sugere ser uma região crítica, em termos de esforços mecânicos. / The system of vertebrae fixation using the pedicular screw is one of the most efficient methods to treat vertebral spine pathologies. When the screw is submitted to pullout strength, it causes internal stress near the medullary canal and this situation can be analyzed using the photoelasticity technique. The objective of this study was to examine the internal stress of a photoelastic vertebrae model using different sizes of screws for the vertebral fixation submitted to pulling out. A lumbar vertebral model made of photoelastic material with three different pedicular screw sizes (5, 6 and 7mm), type USS1 was used. The internal stress around the screw were tested in 18 pre established points by a plain transmission polariscope. The areas of greater concentration of stress were placed between the medullary canal and the transverse process. Comparing the maximum average pulling out stress, statistical differences were observed between screws 5 and 7, and 6 and 7. On the other hand, when screws 5 and 6mm where compared no significant differences were found. This study identified that the internal stress are greater in irregular areas, near the medullary canal, suggesting that this may be a critical region.

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

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published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

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