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Radiotherapy has played an essential role in cancer treatment for over a century, and remains one of the best-studied methods of cancer treatment. Because of its close links with the physical sciences, it has been the subject of extensive quantitative mathematical modelling, but a complete understanding of the mechanisms of radiotherapy has remained elusive. In part this is because of the complexity and range of scales involved in radiotherapy - from physical radiation interactions occurring over nanometres to evolution of patient responses over months and years. This review presents the current status and ongoing research in modelling radiotherapy responses across these scales, including basic physical mechanisms of DNA damage, the immediate biological responses this triggers, and genetic-and patient-level determinants of response. Finally, some of the major challenges in this field, and potential avenues for future improvements are also discussed.
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Objective.To biologically optimise proton therapy, models which can accurately predict variations in proton relative biological effectiveness (RBE) are essential. Current phenomenological models show large disagreements in RBE predictions, due to different model assumptions and differences in the data to which they were fit. In this work, thirteen RBE models were benchmarked against a comprehensive proton RBE dataset to evaluate predictions when all models are fit using the same data and fitting techniques, and to assess the statistical robustness of the models.Approach.Model performance was initially evaluated by fitting to the full dataset, and then a cross-validation approach was applied to assess model generalisability and robustness. The impact of weighting the fit and the choice of biological endpoint (either single or multiple survival levels) was also evaluated.Main results.Fitting the models to a common dataset reduced differences between their predictions, however significant disagreements remained due to different underlying assumptions. All models performed poorly under cross-validation in the weighted fits, suggesting that some uncertainties on the experimental data were significantly underestimated, resulting in over-fitting and poor performance on unseen data. The simplest model, which depends linearly on the LET but has no tissue or dose dependence, performed best for a single survival level. However, when fitting to multiple survival levels simultaneously, more complex models with tissue dependence performed better. All models had significant residual uncertainty in their predictions compared to experimental data.Significance.This analysis highlights that poor quality of error estimation on the dose response parameters introduces substantial uncertainty in model fitting. The significant residual error present in all approaches illustrates the challenges inherent in fitting to large, heterogeneous datasets and the importance of robust statistical validation of RBE models.
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Terapia com Prótons , Prótons , Eficiência Biológica Relativa , Benchmarking , Transferência Linear de Energia , Terapia com Prótons/métodosRESUMO
Background: Impaired recovery of blood pressure (BP) in response to standing up is a prevalent condition in older individuals. We evaluated the relationship between the early recovery of hemodynamic responses to standing and brain health in adults over 50. Methods: Participants from The Irish Longitudinal Study on Ageing (TILDA) (n=411; age 67.6 ± 7.3 years; 53.4 % women) performed an active stand challenge while blood pressure and heart rate were continuously monitored. The recovery of these parameters was determined as the slope of the BP and HR response, following the initial drop/rise after standing. We have previously reported a novel and validated measure of brain ageing using MRI data, which measures the difference between biological brain age and chronological age, providing a brain-predicted age difference (brainPAD) score. Results: Slower recovery of systolic and diastolic BP was found to be significantly associated with higher brainPAD scores (i.e., biologically older brains), where a one-year increase in brainPAD was associated with a decrease of 0.02 mmHg/s and 0.01 mmHg/s in systolic and diastolic BP recovery, respectively, after standing. Heart rate (HR) recovery was not significantly associated with brainPAD score. Conclusion: These results demonstrate that slower systolic and diastolic BP recovery in the early phase after standing is associated with accelerated brain aging in older individuals. This suggests that the BP response to standing, measured using beat-to-beat monitoring, has the potential to be used as a marker of accelerated brain aging, relying on a simple procedure and devices that are easily accessible.
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Transcriptomic personalisation of radiation therapy has gained considerable interest in recent years. However, independent model testing on in vitro data has shown poor performance. In this work, we assess the reproducibility in clinical applications of radiosensitivity signatures. Agreement between radiosensitivity predictions from published signatures using different microarray normalization methods was assessed. Control signatures developed from resampled in vitro data were benchmarked in clinical cohorts. Survival analysis was performed using each gene in the clinical transcriptomic data, and gene set enrichment analysis was used to determine pathways related to model performance in predicting survival and recurrence. The normalisation approach impacted calculated radiosensitivity index (RSI) values. Indeed, the limits of agreement exceeded 20% with different normalisation approaches. No published signature significantly improved on the resampled controls for prediction of clinical outcomes. Functional annotation of gene models suggested that many overlapping biological processes are associated with cancer outcomes in RT treated and non-RT treated patients, including proliferation and immune responses. In summary, different normalisation methods should not be used interchangeably. The utility of published signatures remains unclear given the large proportion of genes relating to cancer outcome. Biological processes influencing outcome overlapped for patients treated with or without radiation suggest that existing signatures may lack specificity.
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AIMS: Cerebral hypoperfusion is implicated in the pathogenesis of associations between orthostatic hypotension and adverse outcome such as falls, cognitive impairment, depression, and mortality. Although the blood pressure response to orthostasis has been well studied there is a lack of information on orthostatic cerebrovascular responses in older populations. METHODS AND RESULTS: We measured cerebral hemodynamics, utilizing near infrared spectroscopy, coupled with peripheral blood pressure during an active stand in a large population of well-phenotyped older adults (N = 2764). Multi-level mixed effect models were utilized to investigate associations with age and sex, as well as confounders including anti-hypertensive medications. Normative cerebral oxygenation responses were also modelled utilizing generalized additive models for location, scale, and shape (GAMLSS). Older age groups experienced larger initial drops in oxygenation and a slower recovery, and responses also differed by sex. The drop after standing ranged from -1.85 % (95 % confidence interval (CI): -2.02 to -1.68) in the males aged 54-59 years vs -1.15 % (95 % CI: -1.31 to -1.00) in females aged 54-59 years, to -2.67 % (95 % CI: -3.01 to -2.33) in males aged ≥ 80 years vs -1.97 % (95 % CI: -2.32 to -1.62) females aged ≥ 80 years. Reduced oxygenation levels were also evident in those taking anti-hypertensive medications. CONCLUSION: Cerebral autoregulation is impaired with age, particularly in older women and those taking anti-hypertensives. SBP during the stand explained some of the age gradient in the late recovery stage of the stand for the oldest age group. Reported orthostatic symptoms did not correlate with hypoperfusion. Therefore, measures of orthostatic cerebral flow should be assessed in addition to peripheral BP in older patients irrespective of symptoms. Further studies are required to investigate the relationship between NIRS measurements and clinical outcomes such as falls, cognitive impairment and depression.
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Anti-Hipertensivos , Hipotensão Ortostática , Idoso , Envelhecimento/fisiologia , Pressão Sanguínea/fisiologia , Feminino , Humanos , Hipotensão Ortostática/epidemiologia , Estudos Longitudinais , MasculinoRESUMO
Multiple transcriptomic predictors of tumour cell radiosensitivity (RS) have been proposed, but they have not been benchmarked against one another or to control models. To address this, we present RadSigBench, a comprehensive benchmarking framework for RS signatures. The approach compares candidate models to those developed from randomly resampled control signatures and from cellular processes integral to the radiation response. Robust evaluation of signature accuracy, both overall and for individual tissues, is performed. The NCI60 and Cancer Cell Line Encyclopaedia datasets are integrated into our workflow. Prediction of two measures of RS is assessed: survival fraction after 2 Gy and mean inactivation dose. We apply the RadSigBench framework to seven prominent published signatures of radiation sensitivity and test for equivalence to control signatures. The mean out-of-sample R2 for the published models on test data was very poor at 0.01 (range: -0.05 to 0.09) for Cancer Cell Line Encyclopedia and 0.00 (range: -0.19 to 0.19) in the NCI60 data. The accuracy of both published and cellular process signatures investigated was equivalent to the resampled controls, suggesting that these signatures contain limited radiation-specific information. Enhanced modelling strategies are needed for effective prediction of intrinsic RS to inform clinical treatment regimes. We make recommendations for methodological improvements, for example the inclusion of perturbation data, multiomics, advanced machine learning and mechanistic modelling. Our validation framework provides for robust performance assessment of ongoing developments in intrinsic RS prediction.
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Benchmarking , Neoplasias , Genômica , Humanos , Neoplasias/genética , Neoplasias/radioterapia , Tolerância a Radiação/genética , TranscriptomaRESUMO
BACKGROUND: Cerebral autoregulation (CAR) systems maintain blood flow to the brain across a wide range of blood pressures. Deficits in CAR have been linked to gait speed (GS) but previous studies had small sample sizes and used specialized equipment which impede clinical translation. The purpose of this work was to assess the association between GS and orthostatic cerebral oxygenation in a large, community-dwelling sample of older adults. METHOD: Data for this study came from the Irish Longitudinal Study on Ageing. A near-infrared spectroscopy (NIRS) device attached to the forehead of each participant (n = 2 708) was used to track tissue saturation index (TSI; the ratio of oxygenated to total hemoglobin) during standing. GS was assessed using a portable walkway. RESULTS: Recovery was impaired in slower GS participants with a TSI value at 20 seconds (after standing) of -0.55% (95% CI: -0.67, -0.42) below baseline in the slowest GS quartile versus -0.14% (95% CI: -0.25, -0.04) in the fastest quartile. Slower GS predicted a lower TSI throughout the 3-minute monitoring period. Results were not substantially altered by adjusting for orthostatic hypotension. Adjustment for clinical and demographic covariates attenuated the association between but differences remained between GS quartiles from 20 seconds to 3 minutes after standing. CONCLUSION: This study reported evidence for impaired recovery of orthostatic cerebral oxygenation depending on GS in community-dwelling older adults. Future work assessing NIRS as a clinical tool for monitoring the relationship between GS and cerebral regulation is warranted.
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Hipotensão Ortostática , Velocidade de Caminhada , Idoso , Envelhecimento/fisiologia , Humanos , Estudos Longitudinais , Posição Ortostática , Velocidade de Caminhada/fisiologiaRESUMO
In this study, the relationship between non-invasively measured cardiovascular signal entropy and global cognitive performance was explored in a sample of community-dwelling older adults from The Irish Longitudinal Study on Ageing (TILDA), both cross-sectionally at baseline (n = 4525; mean (SD) age: 61.9 (8.4) years; 54.1% female) and longitudinally. We hypothesised that signal disorder in the cardiovascular system, as quantified by short-length signal entropy during rest, could provide a marker for cognitive function. Global cognitive function was assessed via Mini Mental State Examination (MMSE) across five longitudinal waves (8 year period; n = 4316; mean (SD) age: 61.9 (8.4) years; 54.4% female) and the Montreal Cognitive Assessment (MOCA) across two longitudinal waves (4 year period; n = 3600; mean (SD) age: 61.7 (8.2) years; 54.1% female). Blood pressure (BP) was continuously monitored during supine rest at baseline, and sample entropy values were calculated for one-minute and five-minute sections of this data, both for time-series data interpolated at 5 Hz and beat-to-beat data. Results revealed significant associations between BP signal entropy and cognitive performance, both cross-sectionally and longitudinally. Results also suggested that as regards associations with cognitive performance, the entropy analysis approach used herein potentially outperformed more traditional cardiovascular measures such as resting heart rate and heart rate variability. The quantification of entropy in short-length BP signals could provide a clinically useful marker of the cardiovascular dysregulations that potentially underlie cognitive decline.
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[Figure: see text].
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Envelhecimento/fisiologia , Pressão Sanguínea/fisiologia , Córtex Cerebral/metabolismo , Tontura/fisiopatologia , Hipotensão Ortostática/fisiopatologia , Oxigênio/metabolismo , Idoso , Estudos Transversais , Humanos , Irlanda , Estudos Longitudinais , Pessoa de Meia-Idade , Estudos Prospectivos , Decúbito Dorsal , Inquéritos e QuestionáriosRESUMO
Due to its cardiovascular effects sedentary behaviour might impact cerebrovascular function in the long term, affecting cerebrovascular regulatory mechanisms and perfusion levels. Consequently this could underly potential structural brain abnormalities associated with cognitive decline. We therefore assessed the association between sedentary behaviour and brain measures of cerebrovascular perfusion and structural abnormalities in community-dwelling older adults. Using accelerometery (GENEActiv) data from The Irish Longitudinal Study on Ageing (TILDA) we categorised individuals by low- and high-sedentary behaviour (≤8 vs >8 hours/day). We examined prefrontal haemoglobin oxygenation levels using Near-Infrared Spectroscopy during rest and after an orthostatic challenge in 718 individuals (66 ± 8 years, 52% female). Global grey matter cerebral blood flow, total grey and white matter volume, total and subfield hippocampal volumes, cortical thickness, and white matter hyperintensities were measured using arterial spin labelling, T1, and FLAIR MRI in 86 individuals (72 ± 6 years, 55% female). While no differences in prefrontal or global cerebral hemodynamics were found between groups, high-sedentary individuals showed lower hippocampal volumes and increased white matter hyperintensities compared to their low-sedentary counterparts. Since these structural cerebral abnormalities are associated with cognitive decline and Alzheimer's disease, future work exploring the causal pathways underlying these differences is needed.
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Encéfalo/irrigação sanguínea , Hemodinâmica/fisiologia , Idoso , Feminino , Humanos , Masculino , Comportamento SedentárioRESUMO
Individuals with anxiety disorders exhibit lower intrinsic functional connectivity between prefrontal cortical areas and subcortical regions. The prefrontal cortex (PFC) is sensitive to the acute and chronic effects of physical activity (PA), while the anxiolytic effects of PA are well known. The current study examined the association of generalized anxiety disorder (GAD) and its interaction with PA, with resting-state, left PFC oxygenation. This cross-sectional study used data from participants (N = 2444) from The Irish Longitudinal Study on Ageing, a nationally representative prospective study of community-living adults aged 50 and older in Ireland. The Composite International Diagnostic Interview Short-Form determined fulfillment of criteria for GAD. The short-form International Physical Activity Questionnaire determined adherence to the World Health Organization PA guidelines. Resting-state, left PFC oxygenation was continuously measured via a Portalite. Tissue saturation index (TSI) was calculated as the ratio of oxygenated hemoglobin to total tissue hemoglobin (expressed as a percentage) for the final minute of a 5-minute supine-rest period. Multivariable linear regression quantified associations of GAD with TSI in the total population and population stratified by PA status. Participants with GAD had lower TSI (b = -1.416, p = .008) compared to those without GAD. However, this association was modified by PA. Among participants who met the PA guidelines, TSI did not differ according to GAD status (b = -0.800, p = .398). For participants who did not meet the guidelines, TSI was significantly lower among those with GAD (b = -1.758, p = .004). These findings suggest that PA may help to protect brain health among older adults with GAD.
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Envelhecimento , Transtornos de Ansiedade , Exercício Físico , Consumo de Oxigênio , Córtex Pré-Frontal , Idoso , Envelhecimento/fisiologia , Envelhecimento/psicologia , Transtornos de Ansiedade/diagnóstico , Transtornos de Ansiedade/epidemiologia , Transtornos de Ansiedade/metabolismo , Transtornos de Ansiedade/fisiopatologia , Conectoma , Estudos Transversais , Exercício Físico/fisiologia , Exercício Físico/psicologia , Feminino , Hemoglobinas/análise , Humanos , Irlanda/epidemiologia , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Córtex Pré-Frontal/irrigação sanguínea , Córtex Pré-Frontal/fisiopatologia , Fatores de Proteção , AutorrelatoRESUMO
BACKGROUND: Orthostasis is a potent physiological stressor which adapts with age. The age-related accumulation of health deficits in multiple physiological systems may impair the physiological response to orthostasis and lead to negative health outcomes such as falls, depression, and cognitive decline. Research to date has focused on changes with orthostasis at prespecified intervals of time, without consideration for whole signal approaches. METHODS: One-dimensional statistical parametric mapping identified regions in time of significant association between variables of interest using a general linear model. Frailty index operationalized accumulated health and social deficits using 32-items from a computer-assisted interview. This study examined the association of frailty index on blood pressure, heart rate, and cerebral oxygenation during an orthostatic test in a sample of 2742 adults aged 50 or older from The Irish Longitudinal Study on Ageing. RESULTS: Frailty index was seen to be negatively associated with cerebral oxygenation changes from baseline over a period of 7 seconds (p = .036). Heart rate and systolic blood pressure were positively and negatively associated with frailty index over periods of 17 seconds (p = .001) and 10 seconds (p = .015), respectively. CONCLUSIONS: Statistical parametric mapping demonstrated these significant regions of cerebral oxygenation during orthostasis provide indirect evidence of impaired autoregulation associated with frailty. Statistical parametric mapping also replicated prior relationships in heart rate and systolic blood pressure associated with a higher frailty index. These findings highlight the utility of 1-dimensional statistical parametric modeling in identifying significant regions of interest in physiological recordings.
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Envelhecimento/fisiologia , Tontura/fisiopatologia , Fragilidade/fisiopatologia , Hipotensão Ortostática/fisiopatologia , Modelos Estatísticos , Idoso , Pressão Sanguínea/fisiologia , Circulação Cerebrovascular , Feminino , Frequência Cardíaca/fisiologia , Humanos , Modelos Lineares , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Oxigênio/sangue , Espectroscopia de Luz Próxima ao Infravermelho , Sístole/fisiologiaRESUMO
BACKGROUND: In total hip arthroplasty the surgeon aims to restore the biomechanics of the joint. Femoral height has the greatest influence on restoring limb length and contributes equally to the restoration of femoral head centre. On X-ray, the level of femoral neck resection is most often referenced off the upper border of lesser trochanter. Less frequently, femoral head centre is referenced from the tip of the greater trochanter. The error in measurement of femoral height resulting from unknown femoral rotation is crucially important and can result in inappropriate surgical planning for implant selection and placement. It is unknown which reference produces lower error. METHODS: A sample of femoral shapes was generated using a femoral statistical shape model. These were placed in a range of orientations in terms of external rotation and flexion, at intervals of 10°. Simulated X-rays were then produced and the distances from the tip of either greater or lesser trochanter to femoral head centre were measured. FINDINGS: Although using greater trochanter as a reference demonstrated greater errors at the extremes, both techniques resulted in errors of 7-8 mm with 20° of both femoral external rotation and flexion. INTERPRETATION: Moderate degrees of femoral external rotation combined with flexion can result in unsatisfactory errors when templating limb length. There should be greater focus and an agreed definition for femoral height. There is a clinical need for a method with a lower error in determining true femoral height and the level of neck resection.
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Artroplastia de Quadril , Cabeça do Fêmur/cirurgia , Período Pré-Operatório , Fenômenos Biomecânicos , Feminino , Fêmur/diagnóstico por imagem , Fêmur/patologia , Fêmur/cirurgia , Cabeça do Fêmur/diagnóstico por imagem , Cabeça do Fêmur/patologia , Colo do Fêmur/diagnóstico por imagem , Colo do Fêmur/patologia , Colo do Fêmur/cirurgia , Humanos , Masculino , RadiografiaRESUMO
In this cross-sectional study, the relationship between noninvasively measured neurocardiovascular signal entropy and physical frailty was explored in a sample of community-dwelling older adults from The Irish Longitudinal Study on Ageing (TILDA). The hypothesis under investigation was that dysfunction in the neurovascular and cardiovascular systems, as quantified by short-length signal complexity during a lying-to-stand test (active stand), could provide a marker for frailty. Frailty status (i.e., "non-frail", "pre-frail", and "frail") was based on Fried's criteria (i.e., exhaustion, unexplained weight loss, weakness, slowness, and low physical activity). Approximate entropy (ApEn) and sample entropy (SampEn) were calculated during resting (lying down), active standing, and recovery phases. There was continuously measured blood pressure/heart rate data from 2645 individuals (53.0% female) and frontal lobe tissue oxygenation data from 2225 participants (52.3% female); both samples had a mean (SD) age of 64.3 (7.7) years. Results revealed statistically significant associations between neurocardiovascular signal entropy and frailty status. Entropy differences between non-frail and pre-frail/frail were greater during resting state compared with standing and recovery phases. Compared with ApEn, SampEn seemed to have better discriminating power between non-frail and pre-frail/frail individuals. The quantification of entropy in short length neurocardiovascular signals could provide a clinically useful marker of the multiple physiological dysregulations that underlie physical frailty.
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Background: A shift towards the dynamic measurement of physiologic resilience and improved technology incorporated into experimental paradigms in aging research is producing high-resolution data. Identifying the most appropriate analysis method for this type of data is a challenge. In this work, the functional principal component analysis (fPCA) was employed to demonstrate a data-driven approach to the analysis of high-resolution data in aging research. Methods: Cerebral oxygenation during standing was measured in a large cohort [The Irish Longitudinal Study on Aging (TILDA)]. FPCA was performed on tissue saturation index (TSI) data. A regression analysis was then conducted with the functional principal component (fPC) scores as the explanatory variables and transition time as the response. Results: The mean ± SD age of the analysis sample was 64 ± 8 years. Females made up 54% of the sample and overall, 43% had tertiary education. The first PC explained 96% of the variance in cerebral oxygenation upon standing and was related to a baseline shift. Subsequent components described the recovery to before-stand levels (fPC2), drop magnitude and initial recovery (fPC3 and fPC4) as well as a temporal shift in the location of the minimum TSI value (fPC5). Transition time was associated with components describing the magnitude and timing of the nadir. Conclusions: Application of fPCA showed utility in reducing a large amount of data to a small number of parameters which summarize the inter-participant variation in TSI upon standing. A demonstration of principal component regression was provided to allow for continued use and development of data-driven approaches to high-resolution data analysis in aging research.
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Assessment of the cerebrovascular and cardiovascular response to standing has prognostic value for a range of outcomes in the older adult population. Studies generally attempt to control for standing speed differences by asking participants to stand in a specified time but little is known about the range of transition times observed. This study aimed to characterize how standing speed associates with cardiovascular and cerebrovascular measures following transition from supine to standing. Continuous cerebral oxygenation, heart rate, systolic and diastolic blood pressure were monitored for 3 minutes after transitioning from supine to standing. An algorithm was used to calculate the time taken to transition from existing Finometer data (from the height correction unit). Linear mixed-effects models were used to assess the influence of transition time on each of the signals while adjusting for covariates. Transition time ranged from 2 to 27 s with 17% of participants taking >10 s to stand. Faster transition was associated with a more extreme decrease 10 s after standing but improved recovery at 20 s for cerebral oxygenation and blood pressure. Standing faster was associated with an elevated heart rate on initiation of stand and a quicker recovery 10 to 20 s after standing. The speed of transitioning from supine to standing position is associated with cardiovascular and cerebrovascular response in the early period after standing (<40 s). Care should be taken in the interpretation of findings which may be confounded by standing speed and statistical adjustment for standing time should be applied where appropriate.
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Envelhecimento/fisiologia , Pressão Sanguínea/fisiologia , Frequência Cardíaca/fisiologia , Hipotensão Ortostática/fisiopatologia , Posição Ortostática , Decúbito Dorsal/fisiologia , Idoso , Feminino , Seguimentos , Humanos , Hipotensão Ortostática/diagnóstico , Hipotensão Ortostática/epidemiologia , Irlanda , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos RetrospectivosRESUMO
Orthopaedic surgeons often experience a mismatch between perceived intra-operative and radiographic acetabular cup orientation. This research aimed to assess the impact of pelvic orientation and surgical positioning technique on operative and radiographic cup orientation. Radiographic orientations for two surgical approaches were computationally simulated: a mechanical alignment guide and a transverse acetabular ligament approach, both in combination with different pelvic orientations. Positional errors were defined as the difference between the target radiographic orientation and that achieved. The transverse acetabular ligament method demonstrated smaller positional errors for radiographic version; 4.0° ±â¯2.9° as compared to 9.4° ±â¯7.3° for the mechanical alignment guide method. However, both methods resulted in similar errors in radiographic inclination. Multiple regression analysis showed that intraoperative pelvic rotation about the anterior-posterior axis was a strong predictor for these errors (BTALâ¯=â¯-0.893, BMAGâ¯=â¯-0.951, pâ¯<â¯0.01). Application of the transverse acetabular ligament method can reduce errors in radiographic version. However, if the orthopaedic surgeon is referencing off the theatre floor to control inclination when operating in lateral decubitus, this is only reliable if the pelvic sagittal plane is horizontal. There is currently no readily available method for ensuring that this is the case during total hip replacement surgery.
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Acetábulo/diagnóstico por imagem , Acetábulo/cirurgia , Artroplastia de Quadril , Fenômenos Mecânicos , Pelve/diagnóstico por imagem , Pelve/cirurgia , Tomografia Computadorizada por Raios X , Período Intraoperatório , Erros MédicosRESUMO
INTRODUCTION:: Acetabular cup orientation during total hip arthroplasty (THA) remains a challenge. This is influenced by patient positioning during surgery and the method used to orientate the acetabular cup. The aim of this study was to assess current UK practice for patient positioning and cup orientation, particularly with respect to patient supports and techniques used to achieve target version and inclination. METHODS:: A literature review and pilot study were initially conducted to develop the questionnaire, which was completed by British Hip Society members ( n = 183). As the majority of THA surgical procedures within the UK are performed with the patient in lateral decubitus, orthopaedic surgeons who operated with the patient in the supine position were excluded ( n = 18); a further 6% were incomplete and also excluded ( n = 11). RESULTS:: Of those who operated in lateral decubitus, 76.6% ( n = 118/154) used the posterior approach. Only 31% ( n = 47/154) considered their supports to be completely rigid. More than 35% ( n = 55/154) were unhappy with the supports that they presently use. The most common methods for controlling operative inclination and version were a mechanical alignment guide (MAG; n = 78/154; 50.6%) and the transverse acetabular ligament (TAL; n = 82/154; 53.2%); 31.2% (48/154) used a freehand technique to control operative inclination. CONCLUSION:: Limited studies have been conducted whereby patient supports have been analysed and key design principles outlined. With 35.7% of the orthopaedic surgeons surveyed having issues with their current supports, a greater awareness of essential characteristics for patient supports is required.
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Artroplastia de Quadril/métodos , Prótese de Quadril , Posicionamento do Paciente , Padrões de Prática Médica , Acetábulo/cirurgia , Idoso , Artroplastia de Quadril/instrumentação , Feminino , Humanos , Ligamentos Articulares/cirurgia , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Inquéritos e Questionários , Reino UnidoRESUMO
Variation in hip joint contact forces directly influences the performance of total hip replacements (THRs). Measurement and calculation of contact forces in THR patients has been limited by small sample sizes, wide variation in patient and surgical factors, and short-term follow-up. This study hypothesised that, at long-term follow-up, unilateral THR patients have similar calculated hip contact forces compared to controls walking at similar (self-selected) speeds and, in contrast, THR patients walking at slower (self-selected) speeds have reduced hip contact forces. It was further hypothesised that there is no difference in calculated hip contact forces between operated and non-operated limbs at long-term follow-up for both faster and slower patients. Gait analysis data for THR patients walking at faster (walking speed: 1.29⯱â¯0.12â¯m/s; nâ¯=â¯11) and slower (walking speed: 0.72⯱â¯0.09â¯m/s; nâ¯=â¯11) speeds were used. Healthy subjects constituted the control group (walking speed: 1.36⯱â¯0.12â¯m/s; nâ¯=â¯10). Hip contact forces were calculated using static optimisation. There was no significant difference (pâ¯>â¯0.31) in hip contact forces between faster and control groups. Conversely, force was reduced at heel strike by 19% (pâ¯=â¯0.002), toe-off by 31% (pâ¯<â¯0.001) and increased at mid-stance by 15% (pâ¯=â¯0.02) for the slower group compared to controls. There were no differences between operated and non-operated limbs for the slower group or the faster group, suggesting good biomechanical recovery at long-term follow-up. Loading, at different walking speeds, presented here can improve the relevance of preclinical testing methods.
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Artroplastia de Quadril , Marcha , Velocidade de Caminhada , Caminhada/fisiologia , Adulto , Idoso , Fenômenos Biomecânicos , Estudos de Casos e Controles , Extremidades , Feminino , Seguimentos , Articulação do Quadril/cirurgia , Humanos , Imageamento Tridimensional , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/fisiologia , Estresse MecânicoRESUMO
Little has changed in the way we report pathology results from blood sciences over the last 50 years other than moving to electronic display from paper. In part, this is aspiration to preserve the format of a paper report in electronic format. It is also due to the limitations of electronic media to display the data. The advancement of web-based technologies and functionality of hand-held devices together with wireless and other technologies afford the opportunity to rethink data presentation with the aim of emphasising the message in the data, thereby modifying clinical behaviours and potentially reducing post-analytical error. This article takes the form of a commentary which explores new developments in the field of infographics and, together with examples, suggests some new approaches to communicating what is currently just data into information. The combination of graphics and a new approach to provocative interpretative commenting offers a powerful tool in improving pathology utilisation. An additional challenge is the requirement to consider how pathology reports may be issued directly to patients.