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

The intent of this research was to identify if the degenerative changes within arteries in the endometrium (endometrial angiopathies) correlate with degenerative changes in the uterine arteries and can be used as a predictor of increased risk for uterine artery rupture (UAR). With this objective specimens from 20 mares that died from uterine artery rupture and 21 control mares that died from unrelated causes were obtained from cases submitted to the University of Kentucky Veterinary Diagnostic Laboratory (UKVDL) over a two-year period. Postmortem specimens of each mare were collected from the left and right uterine arteries at the origin, bifurcation, and distal to the bifurcation as well as full thickness uterine wall sections at five different sites. An additional sample was taken from the uterine artery at the site of rupture in the affected mares. Tissue samples were immersed in 10% neutral buffered formalin, routinely processed, and stained with hematoxylin and eosin, Masson’s Trichrome, and Verhoeff´s Van Gieson histochemical stains as well as a smooth muscle-actin immunohistochemical marker. Elastosis, fibrosis, and vascular smooth muscle cell degeneration were identified in this study as potential contributors of vascular degeneration and a scoring system was developed to differentiate the degrees of severity of these specific degenerative changes within the intima and media of the vascular wall. Based on the scoring system, sections of uterine arteries and endometrial arterioles were blindly examined and the scored changes recorded for statistical analysis. Although the degenerative changes in endometrial and uterine arteries were similar within each group, the results could not not be used to predict an increased risk for UAR. Furthermore, we determined the major changes in vascular pathology of the affected uterine arteries and show there is a significant difference in degenerative changes between specific layers of the vascular wall.

Amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA) are the commonest motor neuron diseases of adult- and childhood onset. Alterations of the RNA binding protein TDP-43 are associated with most cases of ALS, while SMA is caused by deletion of the Survival Motor Neuron (SMN1) gene. SMN has been well characterised in its role in the assembly of the cellular machinery that carries out splicing of pre-mRNA, but is thought to have other functions in RNA metabolism unrelated to pre-mRNA splicing. It is conceivable that specific aspects of RNA handling are disrupted in both SMA and ALS. A variety of genetic, molecular and neuropathological approaches were applied to investigate a potential common pathway in these diseases. The spectrum of genetic mutations underlying motor neuron disorders were explored by screening patient DNA. Cell culture and mouse models were used to test the hypothesis that altered pre-mRNA splicing causes motor neuron death. Human neuropathological specimens were examined for changes in proteins involved in RNA metabolism. The results indicate that altered pre-mRNA splicing is a late occurrence in disease and more likely to be a consequence rather than the cause of motor neuron degeneration. However, the notion that RNA metabolism is highly relevant to motor neuron diseases was strengthened by the discovery of mutations in another RNA binding protein, FUS, in cases of ALS without TDP-43 pathology. Overall the findings highlight the need to consider disruption of mRNA transport and regulation of mRNA translation in future motor neuron disease research.

Motor neuron disorders are a heterogeneous group of diseases characterized by the selective degeneration of motor neurons leading to muscle wasting and atrophy. Amyotrophic Lateral Sclerosis (ALS) is the most common amongst these disorders and is characterized by the selective loss of both upper and lower motor neurons in the brain and spinal cord. 20% of familial cases of ALS are caused by mutations in the Cu, Zn-superoxide dismutase gene (SOD1), a ubiquitously expressed enzyme responsible for scavenging superoxide radicals. The exact mechanisms underlying mutant SOD1-mediated neurotoxicity are unknown. Misfolded mutant SOD1 accumulates in the cytosol and mitochondrial intermembrane space (IMS) indicating the involvement of unfolded protein responses in ALS pathogenesis. Unfolded protein responses (UPRs) are complex signal transduction cascades which detect perturbations in protein folding and couple them to the expression of protein quality control machinery thereby allowing individual compartments to adapt to stress. In the cytosol, this study has shown that HspB8 was upregulated by SOD1 mutants, where it induced the clearance of aggregates by macroautophagy. This is a protective mechanism, as overexpression of HspB8 suppressed mutant-SOD1 mediated toxicity. In contrast, HspB8 mutants were impaired in macroautophagy and are toxic to NSC-34 cells. The mechanisms for the IMS-UPR have not been previously identified. To address this issue, a model for the accumulation of misfolded mutant SOD1 within the IMS was created and candidate proteins involved in protein quality control within the IMS were explored at the transcriptional level and at the level of protein expression. Preliminary results revealed some possible candidates that may have a role in the adaptation to mitochondrial stress. Interestingly, increased mitophagy was also found in IMS-G93A expressing cells, advocating the central role of macroautophagy in eliminating protein aggregates and damaged mitochondria in SOD1-FALS.

Title: Degenerative changes in the cervical spine with a focus on the intervertebral disc prolapse and its verification using imaging methods and 3D model Objectives: The aim of this work is to describe the problems of degenerative changes in the cervical spine with a focus on the intervertebral disc prolapse. The second part deals with the possibility of imaging methods that are able to detect pathological processes. Part of this work is the study of three cases of patients with a diagnosis of disc herniation. In conclusion, there are some possibilities of 3D modeling of the cervical spine. Methods: The theoretical part is based on the available literature. Images from MRI were obtained from medical facilities in Prague, described and assessed by a specialist. After studying the functions suitable graphical programs were created 3D models of the cervical spine. Results: Degenerative changes in the cervical spine naturally come from the aging of the organism, but a number of modifiable factors accelerating the onset. Among such factors include especially hypokinesia and unilateral overloading of cervical spine. Modern imaging techniques can in detail detect these pathological processes, but are limited by the patient's position during the investigation. The resulting series of images are used as...

Orientador: Sheila Canevese Rahal / Resumo: O objetivo do presente trabalho foi avaliar os efeitos da Vibração de Corpo Inteiro (VCI) em cães diagnosticados com displasia coxofemoral. Dez cães diagnosticados com displasia coxofemoral foram submetidos a 48 sessões de VCI, por um período de 16 semanas. Foram avaliadas a musculatura dos membros pélvicos utilizando-se a mensuração da circunferência da coxa, ultrassom muscular e eletromiografia de superfície; a claudicação e os sinais de dor por meio de avaliação visual da claudicação, e questionários preenchidos pelos tutores; análise cinética por meio da plataforma de pressão. A circunferência da coxa em ambos os membros pélvicos e a mensuração ultrassonográfica dos muscúlos glutei no membro pélvico esquerdo e quadriceps femoris bilateral mostraram aumento significativo ao longo do tratamento. Os escores da eletromiografia de superfície do músculo vastus lateralis e os questionários de dor ficaram mais próximos dos padrões de normalidade após 48 sessões de VCI. Por outro lado, a avaliação visual de claudicação e a análise cinética não apresentaram diferenças significativas. Foi possível concluir que o emprego da plataforma vibratória em longo período promoveu melhora da hipotrofia muscular dos membros pélvicos e dos sinais de dor em cães com displasia coxofemoral, mesmo que sem alteração na porcentagem da distribuição de peso ou dos sinais de claudicação. / Abstract: This study aimed to evaluate the effects of Whole-body Vibration (WBV) in dogs with hip dysplasia. Ten dogs with hip dysplasia were submitted to 48 sessions of WBV for a period of 16 weeks. The muscles of the hind limbs were evaluated using measurement of thigh circumference, muscle ultrasound and surface electromyography. Lameness and clinical signs of pain were assessed by visual lameness scoring and owner-based questionnaire, respectively. Kinetic analysis was performed by using a pressure-sensitive walkway. Thigh circumference measurements of both hind limbs and ultrasound measurements of the left hind limb glutei muscles and both right and left quadriceps femoris muscles showed a significant increase. Surface electromyography scores of the vastus lateralis muscle and results of pain questionnaires were close to normal patterns after 48 WBV sessions. On the other hand, no significant differences were observed in visual lameness scoring and kinetic analysis. In conclusion, the use of long term WBV caused improvement of muscle atrophy of the hind limbs and the pain signs in dogs with hip dysplasia, even though alterations in percentage of body weight distribution and lameness signs were not observed. / Mestre

O RDW é um índice hematológico utilizado para avaliação quantitativa da anisocitose eritrocitária, sendo útil na diferenciação das causas de quadros anêmicos. Atualmente, na medicina humana, o RDW tem sido considerado como um importante fator prognóstico em quadros de ICC, mesmo na ausência de anemia. A CRP é considerada a principal proteína de fase aguda sendo amplamente utilizada como marcadora de inflamação. O objetivo deste estudo foi determinar se há diferença nos valores do RDW e da concentração da CRP em cães com DVDCM com e sem ICC, bem como nos diferentes estágios (A, B1, B2, C e D) da doença, segundo a classificação da ACVIM, comparados a cães de raças predispostas, mas sem a doença cardíaca, e associações entre as variáveis. Esta pesquisa constituiu um estudo clínico observacional prospectivo transversal de caráter exploratório, realizada em cães com DVDCM. Para tal, foram selecionados 141 cães, de até 20kg, machos e fêmeas. O grupo com ICC e sem ICC apresentaram menor número de hemácias, hemoglobina e hematócrito em relação ao grupo controle (P<0,001). O índice RDW não diferiu entre os grupos estudados quando foram alocados quanto ao estadiamento ACVIM (P= 0,25), quanto à presença de ICC (P= 0,146), ou de remodelamento cardíaco (P=0,078). Quanto à CRP, os grupos C e D (C: 2.251 ng/dL, 962,05-5.292,5 ng/dL e D: 3.628,4 ng/dL, 4.1592,3-6.254,5 ng/dL) apresentaram concentração maior que o grupo controle (1.685,5 ng/dL, 1.045,45-3.795,5 ng/dL). Quanto ao estadiamento da DVDCM os grupos diferiram entre si (P=0,014) porém, não foi possível identificar quais grupos apresentaram diferença. O grupo com ICC (2.939,7-1.304,25-5.908,8 ng/dL) apresentou maior concentração de CRP em relação ao grupo controle (1.685 ng/dL, 1.1015,45-3.795,5 ng/dL) (P=0,03). O grupo com remodelamento (4.916,66±6.102,14) apresentou maior concentração de CRP em relação ao grupo sem remodelamento (2.510,67±3,26) (P=0,009). Houve correlação positiva fraca entre CRP e número total de leucócitos (r=0,197; P=0,019). Conclui-se que apesar de não ter sido detectada diferença significativa para o RDW houve tendência a valores maiores nos cães com remodelamento comparados aos sem remodelamento. A concentração de CRP foi maior nos cães com remodelamento cardíaco em relação àqueles sem remodelamento e nos cães com ICC em relação aos cães sem ICC e àqueles de raças predispostas, mas sem alterações cardíacas. A dosagem sérica de CRP juntamente com outros marcadores e exames complementares já utilizados rotineiramente, poderá ser útil na avaliação e acompanhamento de pacientes portadores de DVDCM / RDW is a hematological index used for anisocytosis quantitative assesment, and useful to diferenciate anemic states. In human medicine, it has been considered an important prognostic factor in heart failure (HF), even in the absence of anemia. CRP is considered the main acute phase protein, and it is widely used as a marker of inflammation. An exploratory prospective cross sectional study was conducted aiming to determine whether there is a difference in RDW and CRP concentration in dogs with chronic degenerative mitral valve disease (CDMVD) with and without HF, presence of remodeling, as well as between the different disease stages (A, B1, B2, C e D - ACVIM), compared to dogs of predisposed breeds, but without heart disease. For this study, 141 dogs, up to 20kg, males and females were distributed in groups in order to achieve the main golas. Dogs with and without HF presented smaller number of red blood cells, hemoglobin and hematocrit compared to control group (P<0.001). RDW was not diferente between groups for CDMVD stages (P= 0.25), regarding HF presence (P= 0.146), or cardiac remodeling (P=0.078). Groups C and D (C: 2,251 ng/dL, 962.05-5,292.5 ng/dL e D: 3,628.4 ng/dL, 4,1592.3-6,254.5 ng/dL) presented higher CRP concentration compared to control (1,685.5 ng/dL, 1,045.45-3,795.5 ng/dL). There was a difference in CRP concentration between groups, however, it was not possible to identify the differing groups (P=0.014). CRP concentration was higher in HF group (2,939.7-1,304.25-5,908.8 ng/dL) compared to control (1,685 ng/dL, 1,1015.45-3,795.5 ng/dL) (P=0.03). CRP concentration was higher in cardiac remodeling group (4,916.66±6,102.14) in relation to the group without remodeling (2,510.67±3.26) (P=0.009). There was a weak positive correlation between CRP and total leucocyte count (r=0.197; P=0.019). We conclude that although we could not identify a significative difference for RDW, there was a tendency to increased values in dogs with cardiac remodeling. CRP concentration was higher in cardiac remodeling group and in HF group compared to control. CRP serum together with other markers and auxiliary exames already routinely used may provide useful information for assessment and follow up of dogs with CDMVD

Osteoarthritis (OA) is the most common joint disease in human populations with onset and severity influenced by mechanical loading, aging effects, genetics, anatomy, and body mass. Despite major advancements in knowledge, the aetiopathogenesis of OA is complex and still poorly understood. Lack of standardization in methods to quantify skeletal OA make it difficult to study the effects of interacting explanatory variables on arthritic response, and prevents comparison of results between bioarchaeological studies. Joint changes of OA as a function of both the natural aging process and of mechanical stress can make an individual appear older than their chronological age, potentially impacting current methods to derive accurate skeletal age at death estimates, particularly in load-bearing regions. This project addressed these issues through three studies, using a large skeletal sample of modern Europeans for which sex, age, and occupation were available. The first study used principal component analysis (PCA) as a standardized procedure to compute aggregate scores for joint complexes and a systemic measure of OA in each region of the lumbar spine, pelvis, and knee. The second study analyzed the composite scores with a multiple regression model to determine the relative contribution of three predictors: age, activity, and body size, and their effect on skeletal expression of OA in each region. Body size (stature and mass) was calculated from postcranial skeletal measurements; torsional strength (J) of the femoral midshaft was calculated from three-dimensional surface models, size standardized and used as a proxy for measure of activity. The third study considered the effect of OA severity on the validity and reliability of three methods to estimate age at death from load-bearing joints of the os coxa: the pubic symphysis, auricular surface, and acetabulum. The study was designed to determine whether OA in adults acts as a potential limitation or benefit in deriving accurate skeletal age at death estimates from pelvic joint morphology that will contribute to standardized methods in establishing physiological degeneration of the skeleton due to aging. Body size and activity factors did not contribute significantly to OA pathology outside of the age-related expression in either of the lumbar vertebrae or knee regions, and only demonstrated a weak association at pelvic joints. Differences in adult patterns of age are reflected in joint arthritic changes of the os coxa and OA severity has an effect on the accuracy of age estimates from the pelvis; those with OA consistently aging faster in all three joint areas. This influence is most significant for young individuals at the auricular surface and pubic symphysis, over-aging at both. Oldest persons with little arthritic patterning at the acetabulum were under-aged, but accuracy of the age estimate improved as OA severity increased. Systemic measures of OA determined through PCA as an indicator of age, appear useful to identify the very old, but may also help to distinguish between systemic age-related stresses and localized biomechanical effects. Interpreting OA as evidence for old age, measures of habitual activity, and larger body mass should be exercised with caution in skeletal populations. / Graduate / 2018-04-18 / 0327 / 0339 / 0571 / calce.stephanie@gmail.com

Human gait is a complex process that involves the coordination of the central nervous and muscular systems. A disruption to the either system results in the impairment of a person’s ability to walk. Impairments can be caused by neurological disorders such as stroke and physical conditions like amputation. There is not a standardized method to quantitatively assess the gait asymmetry of affected subjects. The purpose of this research is to understand the fundamental aspects of asymmetrical effects on the human body and improve rehabilitation techniques and devices. This research takes an interdisciplinary approach to address the limitations with current rehabilitation methodologies. The goal of my Doctoral research is to understand the fundamental effects of asymmetry caused by physical and neurological impairments. The methods discussed in this document help in developing better solutions to rehabilitate impaired individuals’ gait. I studied four major hypothesis in regards to gait asymmetry. The first hypothesis is the potential of asymmetric systems to have symmetric output. The second hypothesis is that a method that incorporates a wider range of gait parameter asymmetries can be used as a measure for gait rehabilitation. The third hypothesis is that individuals can visually identify subtle gait asymmetries. Final hypothesis is to establish the relationship between gait quality and function. Current approaches to rehabilitate impaired gait typically focus on achieving the same symmetric gait as an able-body person. This cannot work because an impaired person is inherently asymmetric and forcing them to walk symmetrically causes them to adopt patterns that are not beneficial long term. Instead, it is more prudent to embrace the asymmetry of the condition and work to minimize in specific gait parameters that may cause more harm over the long run. Combined gait asymmetry metric (CGAM) provides the necessary means to study the effect of the gait parameters and it is weighted to balance each parameter’s effect equally by normalizing the data. CGAM provides the necessary means to study the effect of the gait parameters and is weighted towards parameters that are more asymmetric. The metric is also designed to combine spatial, temporal, kinematic, and kinetic gait parameter asymmetries. It can also combine subsets of the different gait parameters to provide a more thorough analysis. CGAM will help define quantitative thresholds for achievable balanced overall gait asymmetry. The studies in this dissertation conducted on able-body and impaired subjects provides better understanding of some fundamental aspects of asymmetry in human gait. Able body subjects test devices that aim to make an individual’s gait more asymmetric. These perturbations include a prosthetic and stroke simulator, addition of distal mass, and leg length alterations. Six able-body subjects and one amputee participated in the experiment that studied the effect of asymmetric knee height. The results which consisted of analyses of individual gait parameters and CGAM scores revealed that there is evidence of overall reduction of asymmetry in gait for both able-body subject on prosthetic simulators and transfemoral amputee. The transfemoral amputee also walked with a combination of distal mass with lowered knee height. Although this configuration showed better symmetry, the configuration is detrimental in terms of energy costs. Analyzing the data of gait with the stroke simulator showed that the subject’s gait does undergo alterations in terms of overall gait asymmetry. The distal mass and leg length alteration study has revealed some significant findings that are also reflected in the prosthetic study with distal mass. A leg length discrepancy (LLD) or the change of limb mass can result in asymmetric gait patterns. Although adding mass and LLD have been studied separately, this research studies how gait patterns change as a result of asymmetrically altering both leg length and mass at a leg’s distal end. Spatio-temporal and kinetic gait measures are used to study the combined asymmetric effects of placing LLD and mass on the opposite and same side. There were statistically significant differences for the amount of mass and leg length added for all five parameters. When LLD is added to longer leg, the temporal and kinetic gait parameters of the shorter limb and the altered limb’s spatial parameter become more asymmetric. Contrary to the hypothesis, there was no significant interaction between the amount of mass and leg length added. There were cases in all perturbations where a combination of mass and LLD make a gait parameter more symmetric than a single effect. These cases exhibit the potential for configurations with lower overall asymmetries even though each parameter has a slight asymmetry as opposed to driving one parameter to symmetry and other parameters to a larger asymmetry. CGAM analysis of the results revealed that the addition of distal mass contributes more towards overall asymmetry than LLD. Analyzing 11 gait parameters for LLD and mass on the same side showed that the overall asymmetry decreased for the combination of small LLD and mass. This is consistent with the findings from analyzing five individual gait parameters. Impaired subjects include individuals with stroke and amputees. The clinical trials for individuals with stroke involve training with the Gait Enhancing Mobile Shoe (GEMS) that pro- vides an asymmetric effect on the subject’s step length and time. Training with the GEMS showed improvement in clinical measures such as timed up and go (TUG), six minute walk test (6MWT), and gait velocity. The subjects also showed lower step length symmetry as intended by the GEMS. The ground reaction force asymmetries became more asymmetric as the spatial and temporal parameters became more symmetric. This phenomenon shows evidence that when an individual with stroke is corrected, for spatial and temporal symmetry is at the expense of kinetic symmetry. The CGAM scores also reflected similar trends to that of spatial and temporal symmetry and the r2 correlation with the gait parameters proved that double limb support asymmetry has no correlation with CGAM while ground reaction force asymmetry has a weak correlation. Step length, step, and swing time showed high correlation to CGAM. I also found the r2 correlation between the clinical measures and the CGAM scores. The CGAM scores were moderately correlated to 6MWT and gait velocity but had a weak correlation with TUG. CGAM has positive correlation with TUG and has negative correlation with 6MWT and gait velocity. This gives some validation to CGAM as a potential metric that can be used to evaluate gait patterns based on their asymmetries. Transfemoral amputees were tested for their gait with varied prosthetic knee heights to study the asymmetrical effects and trained split-belt treadmill. Asymmetric knee heights showed improvement in multiple gait parameters such as step length, vertical, propulsive, and braking force asymmetry. It also decreased hip and ankle angle asymmetries. However, these improvements did lead other parameters to become more asymmetric. The CGAM scores reflect this and they show overall improvement. Although the lowest knee height showed improvement, the input from the amputee suggested that the quality of gait decreased with the lowest knee height. These exploratory results did show that a slightly lower knee height may not affect the quality of gait but may provide better overall symmetry. Another exploratory study with split-belt treadmill training, similar to the protocol followed for individuals with stroke, showed definitive improvement in double limb support, swing time, step length and time symmetry. This was also reflected in the improvements seem post training in the CGAM scores as well. I found the r2 correlation of the CGAM and the gait parameters including gait velocity. Step length and swing time show consistent correlation for individual subjects and all the data combined to CGAM. Gait velocity shows a moderate correlation to CGAM for one subject and a high correlation to the other one. However, the combined data of gait velocities does not have any correlation with CGAM. These results show that CGAM can successfully represent the overall gait parameter asymmetry. The trends seen in the gait parameters is closely reflected in the CGAM scores. This research combines the study of asymmetry with people’s perception of human gait asymmetry, which will help in estimating the thresholds for perceivable asymmetrical changes to gait. Sixteen videos were generated using motion capture data and Unity game engine. The videos were chosen to represent the largest variation of gait asymmetries. Some videos were also chosen based on CGAM values that were similar but had large variation in underlying gait parameters. The dataset consisted of results of perturbation experiments on able-body subjects and asymmetric knee height prosthesis on transfemoral amputee. These videos were rated on a seven point Likert scale by subjects from 7 being normal to 1 being abnormal. Thirty one subjects took part in the experiment, out of which only 22 subject’s data was used because they rated at least 3 videos. The results show that the subjects were able to differentiate asymmetric gait with perturbations to able-body gait without perturbation at a self-selected speed. r2 correlation analysis showed that hip angle had mild correlation to the Likert scale rating of the 16 different gait patterns. Multivariate linear regression analysis with a linear model showed significant contribution of ankle and hip angles, vertical, propulsive, and braking forces. It is interesting that the majority of parameters that showed significance are not perceivable visually. Ankle and hip angles are visually perceivable and this significance revealed that subjects seemed to perceive asymmetric ankle and hip angles as abnormal. However, the subjects do not perceive asymmetric knee angles as completely abnormal with evidence of no significance, no correlation, and neutral Likert rating for gait patterns that perturbed knee angles.

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.