Foi avaliada a participação dos corpos vertebrais e discos intervertebrais na lordose lombar e, a contribuição destes nas curvaturas lombares de diferentes magnitudes. Foram avaliadas as radiografias lombares em perfil de 350 adultos assintomáticos (143 homens e 207 mulheres, idade média 29 anos). Foram mensuradas a curvatura lombossacra (L1S1), a curvatura lombolombar (L1L5), a angulação de cada corpo vertebral e cada disco intervertebral por meio de uma variação do método de Cobb. A participação percentual dos corpos vertebrais e dos discos intervertebrais na curvatura lombossacra também foi determinada. Comparações entre os sexos e as faixas etárias foram realizadas. Os indivíduos foram divididos em três subgrupos populacionais, de acordo com a magnitude da lordose lombossacra, de modo a separar os indivíduos pertencentes aos extremos da curva de distribuição. Os componentes da curvatura lombar (corpos vertebrais e discos intervertebrais) foram comparados nestes três subgrupos. A medida da curvatura lombossacra no grupo inicial foi -60,9o (-33o a -89o). Os corpos vertebrais eram cifóticos em L1 (2,15o), tendiam ao neutro em L2 (-0,36o) e eram progressivamente lordóticos de L3 (-1,56o) a L5 (-9,23o). Os discos intervertebrais eram progressivamente lordóticos (variando de -4,99o em L1-L2 a -15,58o em L5-S1). Os corpos vertebrais e discos intervertebrais apresentaram participação progressivamente maior na curvatura lombossacra no sentido crânio-caudal. Os discos intervertebrais participaram com cerca de 80% da curvatura lombossacra, sendo que os elementos mais caudais (corpos vertebrais L4 e L5 e discos intervertebrais L4-L5 e L5-S1) corresponderam a mais de 65% da curvatura lombossacra. Os indivíduos mais velhos apresentaram medidas das curvaturas lombares maiores cerca de 4º em comparação aos indivíduos mais jovens, havendo diferença significante para as medidas dos corpos vertebrais L2 e L5 e o disco intervertebral L3-L4, sendo maiores as medidas nos indivíduos mais velhos. As medidas das curvaturas lombares e dos corpos vertebrais L2 e L4 apresentaram diferença estatisticamente significante entre os sexos, sendo as medidas maiores nos indivíduos do sexo feminino. A curvatura lombossacra apresentou média de -46,9° no subgrupo lordose menor; -61,59° no subgrupo lordose intermediária e; -74,13° no subgrupo lordose maior. A curvatura lombolombar apresentou média de -33,28° no subgrupo lordose menor; -45,34° no subgrupo lordose intermediária e; -56,96° no subgrupo lordose maior. Os corpos vertebrais e os discos intervertebrais apresentaram medidas absolutas menores no subgrupo lordose menor do que as dos subgrupos lordose intermediária e lordose maior, mas a participação dos discos intervertebrais na curvatura lombossacra no subgrupo lordose menor (88%) foi maior que nos subgrupos lordose intermediária (81%) e no subgrupo lordose maior (75%). Complementarmente, os corpos intervertebrais apresentaram maior participação nos subgrupos lordose maior e lordose intermediária. Individualmente, os corpos vertebrais apresentaram maior participação no subgrupo lordose maior, exceto pelo corpo vertebral L5 que apresentou maior participação no subgrupo lordose menor. A maior participação percentual dos discos intervertebrais no subgrupo lordose menor era devida à inclinação cifótica dos corpos vertebrais mais cefálicos (especialmente L1 e L2) no subgrupo lordose menor do que nos demais subgrupos, que, por um efeito compensatório, causava uma maior participação discal nas curvaturas menores. Os demais subgrupos apresentavam os corpos vertebrais cefálicos com inclinação muito mais lordótica do que o observado no subgrupo lordose menor. Concluímos que os discos intervertebrais são os principais responsáveis pela curvatura lombar e que a contribuição dos corpos vertebrais e discos intervertebrais na lordose lombar difere entre indivíduos com curvaturas de diferentes magnitudes. Apesar de ocorrer um aumento gradual do acunhamento lordótico do corpo e disco a cada nível vertebral conforme aumenta a medida da lordose, as vértebras mais cefálicas provocam uma diferença na contribuição percentual entre discos intervertebrais e corpos vertebrais nas curvaturas de tamanhos diferentes. / The vertebral bodies and intervertebral discs participation in lumbar lordosis and their contribution between lumbar curves of different size were studied. 350 lumbar spine radiographs of asymptomatic adults (143 men and 207 women, average age 29 years) were evaluated. Lumbosacral (L1S1) and lumbolumbar (L1L5) curves and the angular inclination of each vertebral boby and intervertebral disc were measured using a Cobb method variant. The percentile participation of each vertebral body and intervertebral disc in the lumbossacal curve was calculated. Sex and age were compared. The subjects were separated in tree subgroups, in acording to lumbosacral curve size. The compounds of lumbar curve (discs and vertebrae) were compared in these tree subgroups. The mean lumbosacral curve was ?60,9º (-33º to ?89º). L1 vertebral body was kyphotic (2,15º), L2 was neutral (-0,36º), and the other ones were progressively lordotic from L3 (-1,56º) to L5 (-9,23º). The intervertebral discs were progressively lordotic from L1-L2 (?4,99º) to L5-S1 (?15,58º). Both vertebrae and discs showed a progressive participation in cephalic-caudal direction. The participation of discs was about 80% of lumbosacral curve, and the caudal elements (L4, L5 vertebrae and L4-L5, L5-S1 discs) contributed far 65% of the curve. The older subjects presented lumbar curves larger than younger 4º average, with significant statistical difference to L2, L5 and L3-L4 measures, with older subjects presenting bigger angular values. There were statistical differences of lumbar curves, L2 and L4 measures between sexes, with females presenting bigger values. The lumbosacral curve presented average -46,9º in minor lordosis subgroup, -64,59º in intermediate lordosis sugbroup, and ?74,13º in major lordosis subgroup. The lumbolumbar curve presented average ?33,28º in minor lordosis subgroup, -45,34º in intermediate lordosis subgroup, and ?56,96º in major lordosis subgroup. The absolut values of vertebrae and discs angles were smaller in minor lordosis subgroup than in major lordosis subgroup, but the intervertebral discs participation of was bigger in minor lordosis subgroup (88%) than intermediate lordosis (81%) and major lordosis (75%) subgroups. Complementarely, the vertebrae had a bigger participation in intermediate and major lordosis subgroups. Individually, the vertebrae presented a larger participation in major lordosis subgroup, excepting L5 that presented bigger participation in minor lordosis subgroup. The discs presented larger participation in minor lordosis subgroup. That is consequence of a more kyphotic inclination of the cephalic vertebrae in minor lordosis subgroup than the other ones, causing a compensating effect, with a larger disc participation in the small curves. The intermediate and major lordosis subgroups had the cephalic vertebrae more lordotic than that of the minor lordosis subgroup. We concluded that the intervertebral discs are the main responsible for the lumbar curve angulation and that the contribution of vertebrae and discs in lumbar curves of different sizes is not equal. In spite of a gradual increase of lordotic wedging while lumbar curve increase, the cephalic vertebrae make the disc and vertebrae participation different between different magnitude lumbar curves.

Introdução- Pacientes portadores de Síndrome Dolorosa Complexa Regional- I (SDCRI) lombar apresentam componente autonômico simpático associado à dor lombar facetaria, são submetidos de forma rotineira à sequência de 4 bloqueios autonômicos associado ao bloqueio do ramo mediano facetário, implicando em 4 procedimentos ambulatoriais por paciente, por semestre. Este estudo visou avaliar a eficácia da realização de ablação por radiofrequência após a realização do bloqueio teste. Métodos- Após aprovação do Comitê de Ética em Pesquisa e consentimento, 25 pacientes portadores de SDCR-I em membros inferiores e dor articular facetária lombar associada foram de forma prospectiva, submetidos a: 1) 4 sessões com intervalos semanais de bloqueio do ramo mediano facetário lombar de L2 a L5 bilateral, associado ao bloqueio do gânglio simpático autonômico L3. Quando a dor atingisse graduação VAS= 4 cm, foi considerado necessário repetição dos procedimentos realizados, e este tempo correspondeu ao tempo de analgesia, sendo calculado o custo anual e efeitos adversos por paciente. Os mesmos pacientes foram submetidos posteriormente a: 1) Bloqueios testes simpático e facetário, seguido de: 2) ablação por radiofrequência (RF) do ramo mediano facetário lombar de L2 a L5 bilateral, com 45 V, 80 segundos, 80 oC, + ablação por RF do gânglio simpático lombar de L3-L4 do lado acometido, 45V, 80 oC, 80 segundos em cada nível acometido, sob sedação consciente, com midazolam e alfentanil por via venosa. Cada paciente atuou como seu próprio controle. Resultados- 21 pacientes participaram da avaliação final. Cada paciente foi submetido a uma sequência semestral de bloqueios, sendo o tempo de analgesia após término do quarto procedimento 5±1 meses, e o custo anual de R$ 15.000,00. Quando os mesmos pacientes foram submetidos à RF, o tempo de analgesia foi em média 15±2 meses (p<0,001), havendo economia no primeiro ano de realização de RF de 23% no custo final e de 32% a 36% nos anos subsequentes, calculado por extrapolação. Durante o período de analgesia, a capacidade para realização de atividades rotineiras e a qualidade de sono melhoraram. Não foram observados efeitos adversos. Discussão- A realização de RF resultou menor número de internações anuais, menor custo anual e maior comodidade para o paciente, com mesma eficácia durante período de analgesia. / Introduction- Patients with Complex Regional Pain Syndrome type-I (CRPS-I) in lower members, often also present lumbar articular facetary pain, and are submitted as part of routine to a sequence of 4 weekly sympathetic blocks combined to facetary block, which sequence is usually repeated after six months for pain control. The study was designed to evaluate the efficacy of a test block followed by radiofrequency efficacy. Methods- After ethical approval and consent, 25 patients with CRPS-I in lower members were submitted to a 4-weekly sympathetic block at L3, combined to bilateral lumbar facetary block fromL2-L5. The sequence was repeated when pain VAS reached 4 cm, and this period was defined as time of analgesia. Thereafter, the same patients were submitted to a test block followed by radiofrequency (RF ablation of sympathetic ganglion L3 and L4 and bilateral ablation of facetary lumbar median branch from L2-L5), 45 V, 80 sec, 80 oC, under conscious sedation. Patients acted as their own control related to analgesia, routine activities, sleep and costs. Results: 21 patients completed the study. The analgesia time after the 4-block sequence was 5±1 months and the annual cost R$ 15.000,00 (USA$5000). The analgesia time after RF was 15±2 months (p<0.001) and the costs were reduced by 23% in the first year and 32%-36% in the following years extrapolation. Routine capacity and sleep at night were equally improved during analgesia for both treatments. There were no adverse effects. Discussion- Test block followed by RF resulted in 15 months of analgesia compared to 5 months for the routine technique of 4-blocks, in improved capacity and sleep comfort at night. Besides that, RF was costly effective, and reduced costs by 23% during the first year evaluation, followed by 32% to 36% cost reduction in following years, by extrapolation.

Corticosteroide por via espinal é uma das alternativas no processo de tratamento da dor radicular quando o tratamento conservador falhou. Sua administração por via epidural vem sendo reavaliada devido ao risco de sequelas, provenientes da obstrução de vasos sanguíneos, associadas a outros efeitos adversos próprios dos corticosteroides. O presente estudo visou avaliar o efeito analgésico da administração de diferentes corticosteroides, exemplificados pela dexametasona e pela betametasona, administrados por via epidural. Vinte e seis pacientes portadores de dor neuropática secundária à hérnia de disco participaram do estudo. A punção sacral foi realizada com combinação de 40 mg de lidocaína, 30 µg de clonidina e 10 mg de dexametasona ou 10 mg de betametasona, diluídos para volume final 10 ml, com solução fisiológica a 0,9%, após comprovação com contraste não-iodado do perfeito posicionamento da agulha no espaço epidural. Este procedimento foi repetido uma vez por semana por 2 semanas seguidas, e após um intervalo de 3 semanas foi realizado mais duas vezes, uma vez por semana, sendo o total de 4 procedimentos por paciente. Treze pacientes iniciaram com dexametasona epidural durante as primeiras duas semanas, e prosseguiram com betametasona após período de descanso de três semanas, sendo que cada paciente atuou como seu próprio controle. Os pacientes foram avaliados em relação à analgesia, incidência de efeitos adversos e alteração das concentrações plasmáticas de íons, cortisol, adrenocorticotrofina e glicemia. Vinte e três pacientes completaram o estudo. Cada paciente foi o seu próprio controle e, no mesmo paciente, o efeito analgésico da dexametasona foi superior ao da betametasona. (p<0,05). Cortisol e adrenocorticotrofina plasmáticos reduziram no sétimo dia após realização do bloqueio (p<0,05), As demais medidas de concentrações plasmáticas de íons Na+, K+, Ca++, glicemia inicial, pós-prandial e hemoglobina glicada foram semelhantes entre os grupos, e sem alteração quando comparados com valores iniciais (p>0,05). Ambos grupos relataram insônia relativa nos primeiros dias pós-bloqueio (p<0,05). Não houve alteração de peso corporal e da pressão arterial durante o tratamento entre os fármacos avaliados (p>0,05). Entretanto, 3 pacientes que receberam dexametasona e 2 que receberam betametasona inicialmente, apresentam medida de pressão ocular aumentada (p<0,05). Como conclusões, a analgesia da dexametasona foi superior quando comparada à da betametasona, (p<0,05). Entretanto ambos grupos apresentaram aumento da pressão ocular e prejuízo do sono noturno, não relevante este último. Finalmente, uma vez que a dexametasona foi superior à betametasona em relação à analgesia e demonstrada ser mais segura em relação à formação de agregados, sugere-se a dexametasona como escolha. / Although the primarily indication of epidural corticosteroids as part of the treatment of acute neuropathic pain when the conservative treatment have failed, recently there have been concerns related to which corticosteroid would be the best indication, as there is the risk of particulate aggregation and serious adverse effects secondary to their own pharmacological properties or intra vessel aggregation and obliteration, as well their efficacy as analgesics. This actual study was designed to evaluate two different corticosteroids, i.e., dexamethasone and betamethasone, as coajuvants in epidural management of acute radicular pain. Twenty-six patients with history of neuropathic pain secondary to disc herniation acted as their own control related to the epidural administration of dexamethasone and betamethasone. Sacral puncture was performed with a combination of 40 mg of lidocaine, 30 µg of clonidine and 10 mg of dexamethasone or 10 mg of betamethasone, diluted to final volume 10 ml with 0.9% physiological solution after non-iodinated contrast of the perfect positioning of the needle in the epidural space.Thirteen patients have started with dexamethasone during the first two weekly procedures, and after 3 weeks of wash-out were submitted to two weekly sequence of sacral betamethasone. The other patients have started with epidural betamethasone, followed by dexamethasone after 3-week rest. Each patient acted as its own control. Patients were evaluated related to analgesia, blood pressure, weight gain, adverse effects and plasmatic measurements of ions, glicemia, ACTH and cortisol. Twenty-three patients completed the study. The analgesic effect was higher when dexamethasone was used in the same patient (p <0.05) Plasma cortisol and ACTH reduced on the 7th day after the block (p<0.05). The plasmatic concentrations of the ions Na+, K+, Ca++, control and post-prandial glicemia, blood pressure, weight were similar between groups and did no differ from initial control values (p>0.05). Both groups reported relative insomnia in the first post-blockade days (P <0.05). However, 3 patients that received dexamethasone and 2 that received betamethasone had ocular pressure increase (p<0.05). As conclusions, both drugs resulted in still unaware increase in ocular pressure and sleep disturbance. Because dexamethasone analgesia was superior and there were no differences regarding adverse effects between either epidural betamethasone or dexamethasone, based on the literature, it would be more appropriate the utilization of dexamethasone.

Back injury in nursing is a significant concern for the health of the worker, the costs to the healthcare system, and the safety of the patients. Current injury prevention measures include ergonomic adjustments to the work environment, the use of mechanical lifting equipment, policies to limit manual handling of patients, and the teaching of lifting techniques. These measures have been met with limited success in reducing injury rates. Little is known about whether changing the lifting biomechanics used in the healthcare setting can lower high injury rates across the profession. The purposes of this dissertation were to: 1) identify the biomechanical risk factors routinely encountered by healthcare workers during the performance of their daily job tasks and 2) determine whether nurses with formal training in weightlifting have better biomechanical performance during routine nursing tasks than nurses with no training. This dissertation included the development of a conceptual model to guide the research. The framework identified the impact of muscle fatigue on the biomechanics used in lifting and moving of heavy equipment and patients. The worker characteristics that affect muscle fatigue include age, gender, height, BMI and the type of recreational activities outside of the workplace. These characteristics were controlled for in two studies aimed at providing a greater understanding of biomechanics used by nurses during routine patient care related activities. The first study addressed a gap in knowledge related to the biomechanics of lifting techniques used by nurses in the work environment, specifically of the anterior rotation of the trunk and pelvis, angles of the hips, knees, and lumbar spine, and muscle activation of core and leg muscles used during patient care activities. We analyzed the biomechanics used by 11 senior level nursing students lifting a simulated patient attached to a rigid spine board from the floor to a standing height. Previous studies have identified that a lumbar spine angle in excess of 22.5 degrees flexion when performing a lift places a worker at a greater risk for back injury. Biomechanical risk factors effecting this lumbar spine angle identified in this study included the anterior rotation of the trunk and pelvis in the starting position of the lift, the angle of the hips and knees during the lifting cycle, the dominate muscle activation of the rectus femoris during the lifting cycle influencing the anterior pelvic rotation, and minimal activation of the core muscles required to add stability to the spine during the lift. This dissertation identifies common biomechanical risk factors routinely encountered by healthcare workers, and gives indication of differences between nurses with formal weightlifting training and those that have not received formal weightlifting training. The differences in body positioning and core stabilization can help reduce the biomechanical risks of back injury in nursing.

Introduction. To test the effects of torsion torques on intradiscal pressure and disc height in human lumbar specimens. Methods. Six human lumbar cadaveric functional spine units (FSU) were loaded in the neutral position with 600 N compression. Nucleus pressure measurements were obtained at 0 Nm, 0.5 Nm, 1.0 Nm and 2 Nm torsion torque. Posterior elements were removed and pressure measurements were repeated at the same torsion torques for the disc body unit (DBU). The pressure in the nucleus was measured by pulling a pressure probe through the disc along a straight path in the midsagittal plane. Results. There was no statistically significant difference of nucleus pressure or intervertebral disc height with different torsion torques among or between the FSU's and DBU's. However, a disc height increase ranging from 0.13 mm to 0.16 mm occurred with the insertion of a 1.85 mm diameter cannula. Conclusions. Small torsion torques showed no significant difference in intradiscal pressures or disc heights. Disc height increases were seen with the insertion of the cannula that could lead to methods of disc height restoration.

Lower back injury remains the most important injury problem in professional cricket with lumbar stress fractures in fast bowlers accounting for the most lost playing time. Previous research has associated workload, paraspinal muscle asymmetry and technique factors with lower back injury in fast bowlers, however, preventative strategies such as workload directives and coaching guidelines have not reduced the incidence and prevalence of these injuries. Recent developments in medical imaging technology have improved diagnosis of pathologies such as lumbar posterior bony element (partes interarticulares and pedicles) stress fractures and intervertebral disc degeneration in athletes whilst also allowing quantification of other, potentially associated factors such as paraspinal muscle asymmetry. However, there is very little published research regarding the use of modalities such as magnetic resonance imaging (MRI) in the identification and prognosis of these types of injuries in fast bowlers. Similarly, advances in three-dimensional (3D) motion analysis has aided technique evaluation in a variety of sports, however, little remains known about the pathomechanics of lower back injury in fast bowling. Therefore, the aim of this doctoral research was to investigate relationships between lower back injury and; the MRI appearance of the lumbar posterior bony elements and intervertebral discs, MRI-derived lumbar muscle morphology and the three-dimensional (3D) trunk kinematics of professional fast bowlers in cricket. This was examined in a series of five studies. The first study undertaken was an investigation of the MRI appearance of the lumbar spines of 36 asymptomatic professional fast bowlers and 17 active controls. / It was identified that the fast bowlers had a high prevalence of multi-level, predominantly non-dominant side, acute and chronic stress changes in the posterior bony elements of the lumbar spine. Multiple level disc degeneration was also more advanced in the fast bowlers compared with the control - iv - participants. However, disc degeneration appeared not to be associated with lumbar stress injury. The second study investigated the reliability and accuracy of using MRI to determine the FCSA of the lumbar paraspinal muscles (psoas, quadratus lumborum, erector spinae and multifidus). The novel methodology developed in this study was determined to be both valid and highly reliable. In the third study, this technique was then used to describe the functional crosssectional area (FCSA) morphology of the paraspinal muscles in a group of 46 professional fast bowlers and the 17 control participants scanned in the first study. It reinforced that there was a higher prevalence of lumbar muscle asymmetry in the fast bowler group. Paraspinal muscle asymmetry, consistent with hypertrophy of the dominant side muscle, was most prevalent in the quadratus lumborum of fast bowlers, and was also evident in the lumbar multifidus in both groups of subjects. The aims of the fourth study of the thesis were to quantify the proportion of lower trunk motion utilised during the delivery stride of fast bowling and to investigate the relationship between the most accepted fast bowling action classification system and potentially injurious kinematics of the lower trunk. 3D kinematic data were collected from 50 male professional fast bowlers during fast bowling trials and these were normalised to each bowler’s standing lower trunk range of motion. A high percentage of the fast bowlers used a mixed bowling action attributable to having shoulder counter-rotation greater than 30°. / The greatest proportion of lower trunk extension (26%), contralateral side-flexion (129%) and ipsilateral rotation (79%) was utilised during the front foot contact phase of the fast bowling delivery stride. There was no significant difference between mixed and non-mixed bowlers in the range of motion used during fast bowling. It was concluded that fast bowling action characteristics currently used to identify potentially dangerous action types may not be directly related to the likely pathomechanics of contralateral side lumbar stress injuries. It is proposed that coupled lower trunk extension, ipsilateral rotation in addition to extreme contralateral side-flexion, during the early part of the front foot contact phase of the bowling action may be an important mechanical factor in the aetiology of this type of injury. In the final study, a combination of the factors described in earlier studies i.e. the lumbar MRI appearance of the partes interarticulares and intervertebral discs, paraspinal muscle asymmetry and selected bowling action and delivery stride trunk kinematic variables, were examined. Therefore, the aim of this study was to examine the relationship between fast bowler lower back injury occurrence (one season either side of testing) and the aforementioned factors that were measured when participants were asymptomatic and bowling competitively. The results of this study indicated that a high percentage of professional fast bowlers in the United Kingdom continue to sustain a high number of acute lumbar stress injuries and these result a significant amount of lost playing and training time. Fast bowling action classification and lower trunk kinematic variables were not conclusively linked to acute lumbar stress injury occurrence. However, further investigation of the effect of coupled lower trunk motion on nondominant side lumbar bone stress is indicated. / The presence of acute MRI stress changes (particularly acute stress changes such as bone marrow oedema, periostitis and acute fracture lines) in the non-dominant side lumbar posterior elements seem to have a relationship with acute stress injury occurrence. Regular lumbar MRI scanning may assist in identifying early acute stress changes prior to the onset of symptoms. Intervertebral disc degeneration was less prevalent amongst professional fast bowlers who suffered acute stress injuries than those who had no significant lower back injury. Finally, although fast bowlers have a high prevalence of quadratus lumborum and lumbar multifidus asymmetry (larger on the dominant side), there was no observed relationship between acute lumbar stress injury and these findings.

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

There have been many advances in surgical residency education and similar interest exists in fellowship education. This study evaluated perceptions among spine surgeons about the specific competencies required for successful spine surgical fellowship training, and then compared these perceptions to clinical practice. Firstly, a questionnaire was administered to spine fellow trainees and academic spine surgeons across Canada in order to identify the cognitive and technical skills required for successful spine fellowship training. Fellowship trainees and supervisors had similar perceptions on the relative importance of specific cognitive and technical competencies. Differences in perceptions were found when comparing surgeons based on background residency specialty training (orthopaedic surgical or neurosurgical). Secondly, using administrative data, a retrospective study assessed volumes, surgeon characteristics, and outcomes for surgery of the degenerative lumbar spine in Ontario between 1995 and 2001. Neurosurgeons were found to perform more decompressions, and more total procedures, than orthopaedic surgeons with similar outcomes.

There have been many advances in surgical residency education and similar interest exists in fellowship education. This study evaluated perceptions among spine surgeons about the specific competencies required for successful spine surgical fellowship training, and then compared these perceptions to clinical practice. Firstly, a questionnaire was administered to spine fellow trainees and academic spine surgeons across Canada in order to identify the cognitive and technical skills required for successful spine fellowship training. Fellowship trainees and supervisors had similar perceptions on the relative importance of specific cognitive and technical competencies. Differences in perceptions were found when comparing surgeons based on background residency specialty training (orthopaedic surgical or neurosurgical). Secondly, using administrative data, a retrospective study assessed volumes, surgeon characteristics, and outcomes for surgery of the degenerative lumbar spine in Ontario between 1995 and 2001. Neurosurgeons were found to perform more decompressions, and more total procedures, than orthopaedic surgeons with similar outcomes.

The dimensions of the lumbar vertebrae are examined in order to determine if these measurements can be used to predict the age of an individual, and if the lumbar vertebrae exhibit sexual dimorphism. Various statistical techniques were utilized to analyze several dimensions of the lumbar vertebrae. Aging patterns in the lumbar elements are distinct between males and females, and females exhibit compression of the L3 element, which may be related to vertebral wedging. Some dimensions of the lumbar vertebrae are sexually dimorphic.