Machine learning driven prediction of cerebrospinal fluid rhinorrhoea following endonasal skull base surgery: A multicentre prospective observational study

Background. Cerebrospinal fluid rhinorrhoea (CSFR) is a common complication following endonasal skull base surgery, a technique that is fundamental to the treatment of pituitary adenomas and many other skull base tumours. The CRANIAL study explored CSFR incidence and related risk factors, particularly skull base repair techniques, via a multicentre prospective observational study. We sought to use machine learning to leverage this complex multicentre dataset for CSFR prediction and risk factor analysis. Methods. A dataset of 865 cases - 725 transsphenoidal approach (TSA) and 140 expanded endonasal approach (EEA) - with cerebrospinal fluid rhinorrhoea as the primary outcome, was used. Relevant variables were extracted from the data, and prediction variables were divided into two categories, preoperative risk factors; and repair techniques, with 6 and 11 variables respectively. Three types of machine learning models were developed in order to predict CSFR: logistic regression (LR); decision tree (DT); and neural network (NN). Models were validated using 5-fold cross-validation, compared via their area under the curve (AUC) evaluation metric, and key prediction variables were identified using their Shapley additive explanations (SHAP) score. Results. CSFR rates were 3.9% (28/725) for the transsphenoidal approach and 7.1% (10/140) for the expanded endonasal approach. NNs outperformed LR and DT for CSFR prediction, with a mean AUC of 0.80 (0.70-0.90) for TSA and 0.78 (0.60-0.96) for EEA, when all risk factor and intraoperative repair data were integrated into the model. The presence of intraoperative CSF leak was the most prominent risk factor for CSFR. Elevated BMI and revision surgery were also associated with CSFR for the transsphenoidal approach. CSF diversion and gasket sealing appear to be strong predictors of the absence of CSFR for both approaches. Conclusion. Neural networks are effective at predicting CSFR and uncovering key CSFR predictors in patients following endonasal skull base surgery, outperforming traditional statistical methods. These models will be improved further with larger and more granular datasets, improved NN architecture, and external validation. In the future, such predictive models could be used to assist surgical decision-making and support more individualised patient counselling

Storytelling: global perspectives on narrative

This book is a collection of papers from an international inter-disciplinary conference focusing on storytelling and human life. The chapters in this volume provide unique accounts of how stories shape the narratives and discourses of people’s lives and work; and those of their families and broader social networks. From making sense of history; to documenting biographies and current pedagogical approaches; to exploring current and emerging spatial and media trends; this book explores the possibilities of narrative approaches as a theoretical scaffold across numerous disciplines and in diverse contexts. Central to all the chapters is the idea of stories being a creative and reflexive means to make sense of people’s past, current realities and future possibilities

The Effect of CO2 Phase on Oil Displacement in a Sandstone Core Sample

CO2 sequestration in saline aquifers and hydrocarbon reservoirs is a promising strategy to reduce CO2 concentration in the atmosphere and/or enhance hydrocarbon production. Change in subsurface conditions of pressure and temperature and CO2 state is likely to have a significant impact on capillary and viscous forces, which, in turn, will have a considerable influence on the injection, migration, displacement, and storage capacity and integrity of CO2 processes. In this study, an experimental investigation has been performed to explore the impact of fluid pressure, temperature, and injection rate, as a function of CO2 phase, on the dynamic pressure evolution and the oil recovery performance of CO2 during oil displacement in a Berea sandstone core sample. The results reveal a considerable impact of the fluid pressure, temperature, and injection rate on the differential pressure profile, cumulative produced volumes, endpoint CO2 relative permeability, and oil recovery; the trend and the size of the changes depend on the CO2 phase as well as the pressure range for gaseous CO2–oil displacement. The residual oil saturation was in the range of around 0.44–0.7; liquid CO2 gave the lowest, and low-fluid-pressure gaseous CO2 gave the highest. The endpoint CO2 relative permeability was in the range of about 0.015–0.657; supercritical CO2 gave the highest, and low-pressure gaseous CO2 gave the lowest. As for increasing fluid pressure, the results indicate that viscous forces were dominant in subcritical CO2 displacements, while capillary forces were dominant in supercritical CO2 displacements. As temperature and CO2 injection rates increase, the viscous forces become more dominant than capillary forces

The pathophysiology of chronic subdural haematoma and the role of the dexamethasone

Chronic subdural haematoma (CSDH) is an encapsulated collection of blood and fluid overlying the surface of the brain, which is often treated with surgical drainage to prevent cerebral compression. Despite treatment it can recur, requiring further surgery and causing significant morbidity. Historically CSDH formation was considered to occur due to the ageing and expansion of acute bleeding following head trauma. However, within this thesis the natural progression of CSDH was assessed with serial imaging following trauma and highlighted the novel process of CSDH formation from a normal CT. This was hypothesised to occur through injury initiating inflammation within the subdural space which drives formation of a hypervascular membrane responsible for fluid and blood accumulation over time. This theory was investigated by examining 68 CSDH samples for the presence of selected inflammatory markers and haemoglobin concentration. All pro-inflammatory markers were significantly elevated in CSDH fluid compared to venous blood, particularly vascular endothelial growth factor (VEGF). Haemoglobin degradation products were quantified with UV-Vis spectroscopy and more recent haemorrhage indicated an increased CSDH recurrence risk. This work was performed alongside the Dex-CSDH trial, a randomised, placebo-controlled trial of the potent anti-inflammatory dexamethasone. Blinded interim results of the trial are discussed, but the main focus are the scientific, mechanistic sub-studies. A method for detecting dexamethasone in CSDH and blood was developed using high performance liquid chromatography (HPLC), and suggested there is no accumulation of the drug within the CSDH space. However, many of the inflammatory markers were reduced post-operatively following dexamethasone treatment. Volumetric and density analysis of pre-operative and post-operative imaging was also performed and may aid prediction of which patients are more likely to have a poor outcome or recurrence. This could help identify patients in the future who would benefit most from adjuvant therapies such as dexamethasone.Royal college of Surgeons of England research fellowship, Rosetrees Trust funding and National Institute of Health Research (NIHR)- Health Technology Assessment (HTA) funding for the Dex-CSDH trial

An action learning based reflection on participative drama as a tool for transformation of identity in the spirals programme

This thesis is a reflection on both the conceptual frameworks and the personal narratives that have shaped the development of the Spirals Programme. The Programme is a participatory drama and creative arts based initiative established in 2000 in Grahamstown, South Africa, to explore issues of identity in the emerging democratic context of South African society - and support both personal and contextual processes of transformation. Working within a poststructuralist and social constructionist paradigm, Spirals works with groups and communities to facilitate and enable experiential links between the drama based and performative nature of identity construction - and the possibilities for transformation and healing provided by participative drama methodologies. The structure of the thesis follows the principles of the Freirian based Action Learning praxis within which Spirals works. It begins with an account of the contextual dynamics and events that gave rise to the development of the Programme, followed by a reflection on the conceptual frameworks regarding both identity construction and participative drama methodologies that informed Spirals' development. These paradigms are then analysed in relation to the articulated experiences of three workshop participants using critical discourse analysis. The thesis concludes with an assessment of the issues emerging from this analysis - the aspects of the Programme that need to be strengthened and sustained, those that need to be changed and possible new strategies that could be developed.Also known as: Edlmann, Theres

Understanding the interplay of capillary and viscous forces in CO2 core flooding experiments

Interaction between capillary and viscous forces significantly affects the flow instability in immiscible displacement, which is usually investigated by visualization of flow patterns in 2d porous micromodels or in 3d system equipped with X-ray CT. However, in most practical applications, visualization of flow in porous media is not possible and the pressure signal is often as one of the important sources of information. Core flooding experiments were implemented in this study to investigate the interplay of capillary and viscous effects by analysis of differential pressure. Water and crude oil were employed as defending fluid, and different states of CO2 were injected as invading fluid. The inlet was set as the constant injection flow rate while the outlet as the constant pressure. In viscous-dominated displacement, differential pressure evidently depends on the injection rate and the pressure decline curve is fitted by a power function. The exponent of the function is found to be significantly larger at the crossover between capillary-dominated and viscous-dominated regions. In capillary-dominated displacement, the pressure profile is characterized by a pressure jump at the beginning and intermittent fluctuations during the displacement. Further analysis by wavelet decomposition indicates a transition point existing in standard deviation of pressure fluctuations when the displacement is transformed from capillary-dominated to viscous-dominated. The experimental results are finally verified by a macroscopic capillary number, which characterizes the interaction between capillary and viscous forces at a critical value of , agreeing well with the Log Nca-Log M phase diagram