bluuebunny/crossref_metadata_2025 huggingface dataset:
Multivariable machine learning models for clinical prediction of subsequent hip fractures in older people using the Chinese population database
Authors: Huang Wenbo , Wang Jie , Xu Jilai , Guo Guinan , Chen Zhenlei , Xue Haolei
Published: March 2024

Purpose

This study aimed to develop and validate clinical prediction models using machine learning (ML) algorithms for reliable prediction of subsequent hip fractures in older individuals, who had previously sustained a first hip fracture, and facilitate early prevention and diagnosis, therefore effectively managing rapidly rising healthcare costs in China.

Methods

Data were obtained from Grade A Tertiary hospitals for older patients (age ≥ 60 years) diagnosed with hip fractures in southwest China between 1 January 2009 and 1 April 2020. The database was built by collecting clinical and administrative data from outpatients and inpatients nationwide. Data were randomly split into training (80%) and testing datasets (20%), followed by six ML-based prediction models using 19 variables for hip fracture patients within 2 years of the first fracture.

Results

A total of 40,237 patients with a median age of 66.0 years, who were admitted to acute-care hospitals for hip fractures, were randomly split into a training dataset (32,189 patients) and a testing dataset (8,048 patients). Our results indicated that three of our ML-based models delivered an excellent prediction of subsequent hip fracture outcomes (the area under the receiver operating characteristics curve: 0.92 (0.91–0.92), 0.92 (0·92–0·93), 0.92 (0·92–0·93)), outperforming previous prediction models based on claims and cohort data.

Conclusions

Our prediction models identify Chinese older people at high risk of subsequent hip fractures with specific baseline clinical and demographic variables such as length of hospital stay. These models might guide future targeted preventative treatments.
Identifying excessive chronic alcohol use with phosphatidylethanol in patients with suspected severe injury-results from the IDART study
Authors: Jørgenrud Benedicte M , Bråthen Camilla C , Steinson Stenehjem Jo , Kristiansen Thomas , Rosseland Leiv Arne , Bogstrand Stig Tore
Published: March 2024

Introduction

Acute and chronic alcohol use are well-known risk factors for accidents and injuries, and concurrent psychoactive drug use can increase injury risk further. Phosphatidylethanol (PEth) 16:0/18:1 is a biomarker used to determine alcohol consumption the previous 3–4 weeks. The aim was to investigate the prevalence of chronic alcohol use in trauma patients, as determined by PEth 16:0/18:1 concentrations, and how excessive chronic alcohol use relate to demographic variables, injury mechanisms and drug use.

Setting

Patients received at Norwegian trauma hospitals from March 2019 to February 2020. The study is part of the Impairing Drugs and Alcohol as Risk factors for Traumatic Injuries study.

Methods

All patients aged ≥ 16 years received with trauma team were included in the study. Data on injury date and mechanism, gender and age was registered. Blood samples were analyzed for 22 psychoactive medicinal and illicit drugs, ethanol and phosphatidylethanol 16:0/18:1. Regression analyses were conducted to assess associations between alcohol use and gender, age, injury mechanism and drug use.

Results and Conclusion

Of the 4845 patients included in the study, 10% had PEth 16:0/18:1 concentration ≥ 600 nM (~430 ng/mL), indicative of excessive chronic alcohol use. Being male, between 44-61 years old, involved in violence, and testing positive for medicinal drugs was associated with excessive chronic alcohol use.

Excessive chronic alcohol use was common among males, middle-aged, patients with violence as injury mechanism and those with medicinal drug use. These findings emphasize the need to detect and treat excessive chronic alcohol use among trauma patients.
Efficient computation of high-dimensional penalized generalized linear mixed models by latent factor modeling of the random effects
Authors: Heiling Hillary M , Rashid Naim U , Li Quefeng , Peng Xianlu L , Yeh Jen Jen , Ibrahim Joseph G
Published: March 2024

Modern biomedical datasets are increasingly high-dimensional and exhibit complex correlation structures. Generalized linear mixed models (GLMMs) have long been employed to account for such dependencies. However, proper specification of the fixed and random effects in GLMMs is increasingly difficult in high dimensions, and computational complexity grows with increasing dimension of the random effects. We present a novel reformulation of the GLMM using a factor model decomposition of the random effects, enabling scalable computation of GLMMs in high dimensions by reducing the latent space from a large number of random effects to a smaller set of latent factors. We also extend our prior work to estimate model parameters using a modified Monte Carlo Expectation Conditional Minimization algorithm, allowing us to perform variable selection on both the fixed and random effects simultaneously. We show through simulation that through this factor model decomposition, our method can fit high-dimensional penalized GLMMs faster than comparable methods and more easily scale to larger dimensions not previously seen in existing approaches.
Bayesian mixed model inference for genetic association under related samples with brain network phenotype
Authors: Tian Xinyuan , Wang Yiting , Wang Selena , Zhao Yi , Zhao Yize
Published: March 2024

Genetic association studies for brain connectivity phenotypes have gained prominence due to advances in noninvasive imaging techniques and quantitative genetics. Brain connectivity traits, characterized by network configurations and unique biological structures, present distinct challenges compared to other quantitative phenotypes. Furthermore, the presence of sample relatedness in the most imaging genetics studies limits the feasibility of adopting existing network-response modeling. In this article, we fill this gap by proposing a Bayesian network-response mixed-effect model that considers a network-variate phenotype and incorporates population structures including pedigrees and unknown sample relatedness. To accommodate the inherent topological architecture associated with the genetic contributions to the phenotype, we model the effect components via a set of effect network configurations and impose an inter-network sparsity and intra-network shrinkage to dissect the phenotypic network configurations affected by the risk genetic variant. A Markov chain Monte Carlo (MCMC) algorithm is further developed to facilitate uncertainty quantification. We evaluate the performance of our model through extensive simulations. By further applying the method to study, the genetic bases for brain structural connectivity using data from the Human Connectome Project with excessive family structures, we obtain plausible and interpretable results. Beyond brain connectivity genetic studies, our proposed model also provides a general linear mixed-effect regression framework for network-variate outcomes.
O114: Enhancing palliative oesophageal cancer treatment pathway prediction and prognostication through machine learning models
Authors: Thavanesan Navamayooran , Parfitt Charlotte , Bodala Indu , Walters Zoë , Ramchurn Sarvapali , Underwood Timothy , Vigneswaran Ganesh
Published: March 2024

Introduction

Non-curative treatment plans comprise the majority of Oesophageal Cancer (OC) decision-making by Multidisciplinary Teams (MDTs), operating under significant caseload pressures. Machine Learning (ML) can semi-automate, streamline, and standardise these decisions to predict treatments and prognosticate for new patients. We present ML models which predict treatment decisions and prognostication in palliative OC patients.

Methods

Using clinicopathological data from 437 palliative OC cases treated at a single tertiary centre over 12 years, we trained several ML algorithms (Multinomial Logistic Regression [MLR], Random Forests [RF], Extreme Gradient Boost [XGB], Decision Tree [DT], and Random Survival Forests [RSF]) to predict treatment pathways (best supportive care, chemotherapy, radiotherapy, palliative stent, or stent plus oncological adjunct) and survival prognoses. Model performance was evaluated using Area Under the Curve (AUC) for classifier models and C-index (1-concordance) along with calibration plots for the survival model. Additionally, the models were integrated into a web application for clinician-friendly usability.

Results

Mean AUCs for the classifier models were: MLR 0.801±0.090, RF 0.806±0.078, XGB 0.817±0.079 and DT 0.762±0.108. Mean C-Index for the RSF survival model was 0.330±0.018 while calibration curves showed good calibration within the first 6-12months (median survival for the cohort was 6.31 months (range 0.1-105.8 months)).

Conclusion

This study is the first use of ML to predict palliative treatment plans and offer prognostication for OC patients, seamlessly integrated into a user-friendly interface for real-time treatment pathway prediction. This offers significant potential to streamline MDT caseload and provide data-driven decision-support for clinicians counselling these patients.
O225: Oxygenated hypothermic machine perfusion (HMPO2) of the pancreas; a porcine circulatory death model to compare a ‘continuous’ and an ‘end-ischaemic’ approach
Authors: Elzawahry Mohamed , Fallon John , Nawaz Sameena , Hastoy Benoit , Clark Anne , Ploeg Rutger , Friend Peter , Hunter James
Published: March 2024

Pancreas and islet cell transplantation are used in the treatment of patients with diabetes complications. During static cold storage (SCS) ATP is depleted, and by-products of anaerobic respiration accumulate. Ischaemia-reperfusion injury (IRI) affects quantity and viability of islets and it is characterised by acinar necrosis, oedema, and endothelial disruption (graft pancreatitis). The introduction of HMPO2 in liver & kidney preservation has demonstrated a significant reduction in the consequences of IRI. Pancreas HMPO2 was shown to be feasible in pre-clinical studies. We aimed to compare a ‘continuous’ to an ‘end-ischaemic’ approach of HMPO2 in pancreases using a porcine circulatory death model. Porcine pancreases were either started on HMPO2 for the totality of the cold storage time (‘Continuous’ group, n=6) or for the last two hours of the cold storage time (‘End’ group, n=6). All pancreases then underwent normothermic reperfusion (NR) to mimic transplantation. Glucose stimulated insulin secretion (GSIS) was measured using Mercodia human insulin ELISA (n=3 in each group). Both groups had no significant change of wet-to-dry ratio during the experiment, despite an increase in gross weight. Flows were higher during NR in the Continuous group. Amylase, Lipase and LDH increased throughout the study for all pancreases and showed no statistically significant difference between both groups. The Continuous group had a significantly greater insulin secretion in response to glucose stimulation and followed a biphasic pattern. Continuous HMPO2 preserved islet function and was a superior mode of preservation, showing no statistically significant difference in oedema or markers of damage, with improved perfusion parameters.
O148: Unlocking Enhanced Immunity in Pancreatic Ductal Adenocarcinoma: Activins Interplay with CAF-Stroma Mechanisms
Authors: McCluney Simon , Park Danielle , Miller Daniel , Bloxham Robert , Mehic Merima , de Vries Emma , Wang Xuelu , Wilkinson Robert , Hunt James , Hyvonen Marko , Boeing Stefan , Sarker Debashis , Hill Caroline
Published: March 2024

SMAD4 is a tumour suppressor gene that is mutated in up to 60% of pancreatic ductal adenocarcinoma (PDAC) tumours. Activins are members of the TGF-b signalling superfamily which signal through SMAD4 and are generally associated with an oncogenic process, with differing effects on tumour and stromal cells, such as cancer associated fibroblasts (CAFs). We sought to further elucidate the role of activin within PDAC and perturb activin signalling in vitro and in vivo. Analysis was performed of publicly available human datasets alongside human and murine single-cell RNA-sequencing datasets to study the effect of activin expression on survival and tumourigenesis. We developed anti-activin monoclonal antibodies to perturb activin signalling in PDAC mice, with deep analysis of tumour composition including immune cells and CAFs via a multitude of basic science techniques. We demonstrated that circulating activin levels are higher in PDAC patients than in healthy volunteers, whilst activin overexpression is associated with reduced overall survival in PDAC patients. Activin was shown to be predominantly expressed by contractile (collagen-depositing) CAFs, as opposed to inflammatory CAFs. Activin expression co-localises with fibroblasts, and anti-activin antibodies can reduce the collagen content of dense PDAC tumours. Additionally, anti-activin antibodies led to a statistically significant increase in CD4 and CD8 T-cell infiltration into murine PDAC tumours. We have shown that activin is overexpressed in PDAC, and high expression is associated with a more aggressive disease process. Anti-activin antibodies can alter the composition of desmoplastic PDAC tumours and increase the immune infiltrate of these typically “immune cold” tumours.
O126: Non-invasive vagus nerve stimulation to reduce ileus after colorectal surgery: randomised feasibility trial and efficacy assessment
Authors: Chapman Stephen , Kowal Mikolaj , Helliwell Jack , Naylor Maureen , Pyrah Harriet , Mappa Georgia , Croft Julie , Farley Katherine , Stocken Deborah , Jayne David
Published: March 2024

Objective

Ileus is characterised by intestinal dysmotility after surgery. In preclinical models, vagus nerve stimulation reduces intestinal inflammation, preventing smooth muscle dysfunction and accelerating the return of gut function. This study explored the efficacy and feasibility of a definitive trial and implementation of non-invasive, electrical, vagus nerve stimulation (nVNS).

Design

A participant-blinded, multi-centre, feasibility trial of self-administered nVNS was performed. Patients undergoing colorectal surgery were randomised to four groups of pre- and post-operative treatment (A: nVNS/nVNS; B: nVNS/Sham; C: Sham/nVNS; D: Sham/Sham). Feasibility outcomes were participant recruitment, compliance, and blinding. Clinical outcomes were intestinal function and adverse events. Interviews with patients and clinicians explored barriers to feasibility and implementation. In an independent cohort, the effects of nVNS on serum IL-1b, IL-6, and TNFa were quantified at baseline, 24-hours, and 72-hours after surgery.

Results

Ninety-seven out of 125 (77.6%) eligible patients took part. The median compliance was 19 out of 20 stimulations (IQR: 17-20). The median time to pass stool was 4 (3-5), 3 (2-4), 2.5 (2-3.5), and 3 (2-4) days for groups A-D, respectively. The incidence of adverse events was similar across groups. Trends toward reduced pro-inflammatory mediators were observed after nVNS. Interviews with patients (n=19) demonstrated their motivation to contribute actively to their recovery and interviews with clinicians (n=10) revealed strong reciprocal support.

Conclusion

This study confirms the safety, feasibility, and support for nVNS after surgery. Research on nVNS should progress from its current focus on pre-clinical models to powered, dedicated assessments of clinical effectiveness.
O250: Blood Pressure Homeostasis and Hyper-perfusion Syndrome Following Carotid Surgeries
Authors: Acharya Yogesh , Hynes Niamh , Sultan Sherif
Published: March 2024

Objectives

We aim to compare blood pressure homeostasis in patients undergoing bilateral versus unilateral carotid surgeries. Our primary endpoints are the incidence of postoperative hypertension and hyperperfusion syndrome (HPS). Secondary endpoints are major adverse cardiovascular events and all-cause mortality.

Methods

All patients undergoing carotid endarterectomy (CEA) from 2003 to 2022 were reviewed. We performed 1230 carotid interventions, of which 690 procedures had ten years of follow-up.

Results

Both the unilateral (512) and bilateral (91) carotid interventions caused a significant acute elevation in blood pressure (p<0.001). In unilateral carotid interventions, the mean SBP was 137 ± 19.90 mmHg preoperatively and 152 ± 25.80 postoperatively (p<0.001). Smoking (p=0.007), hyperfibrinogenemia (p=0.004), emergency admission (p=0.005), ipsilateral carotid stenosis >90% (p=0.022), and previous ipsilateral carotid intervention (p=0.003) were significantly associated with the development of postoperative hypertension. No incidence of HPS occurred in the unilateral group. In bilateral carotid interventions, the mean SBP was 138 ± 20.50 mmHg preoperatively and 159 ± 24.60 mmHg postoperatively (p<0.001). Emergency admission (p=0.012) and plaque morphology (p=0.035) were significantly associated with postoperative hypertension. Three patients with bilateral carotid interventions had HPS (3.3%) and developed hemorrhagic stroke within 30 days. Multivariate analysis found postoperative stage II hypertension following bilateral carotid procedures to be an independent predictor of stroke (p=0.004). However, postoperative hypertension was not an independent predictor of myocardial infarction (p=0.475) and mortality (p=0.608).

Conclusion

Significant acute elevation in blood pressure occurred following carotid surgeries. We observed HPS post bilateral carotid interventions, with postoperative hypertension being an independent predictor of peri-operative stroke.
O92: Machine perfusion in liver transplantation; Cochrane review and meta-analysis
Authors: Tingle Samuel , Dobbins Joseph , Thompson Emily , Figueiredo Rodrigo , Mahendran Balaji , White Steve , Pandanaboyana Sanjay , Wilson Colin
Published: March 2024

Introduction

Several novel machine perfusion technologies have been developed which attempt to improve outcomes compared with ice-box static cold storage (SCS). We aimed to evaluate the effects of different methods of machine perfusion liver transplantation.

Methods

We used standard, extensive Cochrane search methods to identify randomised machine perfusion trials. Data extraction was performed independently by two authors. Pairwise random-effects meta-analysis was performed. We assessed bias using Risk of Bias 2 and used GRADE to assess certainty of evidence.

Results

We included seven randomised trials (1024 transplant recipients from 1301 randomised/included livers); four compared end-ischaemic hypothermic oxygenated perfusion (HOPE) with SCS, and three compared normothermic machine perfusion (NMP) with SCS. When compared with SCS, HOPE was associated with improvement in the following clinically relevant outcomes: graft survival (HR=0.45, 95% CI=0.23-0.87; P=0.02; high-certainty evidence), serious adverse events (OR=0.45, 0.22-0.91; P=0.03; moderate-certainty evidence) and clinically significant ischaemic cholangiopathy (OR=0.31, 0.11-0.92; P=0.03; high-certainty evidence). NMP was not associated with improvement in any of these clinically relevant outcomes, although evidence for these outcomes was low certainty. NMP was associated with improved utilisation compared with SCS (one trial found a 50% lower rate of organ discard; P = 0.008).

Conclusions

Where the decision has been made to transplant a DCD or marginal DBD liver, HOPE will provide superior clinically relevant outcomes compared with SCS alone (graft survival, adverse events, cholangiopathy). NMP appears to improve utilisation of grafts that would otherwise be discarded, but well-powered trials specifically designed to assess utilisation are required.
O254: Open Latarjet Procedure in Athletes With a Minimum of 5 Years Follow Up: An Analysis of Factors Associated With Success
Authors: Doyle Tom , Keogh Carl , Kilkenny Conor , Moore Thomas , Kearney Jack , Albersharah Bader , Khan Sami , Hurley Eoghan , Mullett Hannan
Published: March 2024

Introduction

The open Latarjet (OL) procedure has shown excellent return to play (RTP) and low recurrence in athletes but there is limited published evidence for long term outcomes. The purpose of this study was to evaluate the outcomes of athletes 5-years post-operatively following the OL procedure.

Methods

A retrospective review of athletes who underwent OL under a single surgeon with a minimum of 5-year follow-up was performed. Multi-linear regression models were used to evaluate factors affecting postoperative satisfaction, and SSV level.

Results

141 shoulder in 132 male athletes who underwent OL were included, with a mean age of 22.9 years, with mean follow-up of 71.5months. At final follow up, 93.7% were satisfied/very satisfied, and the mean SSV was 85.5. Overall, the rate of RTP was 91.3%, with 80.8% returning at the same level at a mean of 7.3months. There were 9 athletes (6.4%) who experienced further dislocation, all during collision sports. In total 10 (7.1%) athletes had a further operation, of which 3 (2.4%) were for recurrent instability. The mean SIRSI score was 82.1 ± 27.3, the mean Rowe score was 85.4, while the mean VAS score was 2.1. Linear regression revealed the SIRSI, VAS and Rowe score as well as RTP were significantly associated with SSV score. 90.6% of athletes reported they would undergo the procedure again were it required.

Conclusion

There was very high rate of satisfaction, with excellent patient-reported outcomes, low rates of recurrent instability and a high rate of return to play among athletes.
O138: Predictors of early recurrence of oesophagogastric adenocarcinoma after neoadjuvant FLOT
Authors: Dayanamby Abbienaya , Chmelo Jakub , Bradshaw Alexander , Phillips Alexander
Published: March 2024

Background

Although survival of patients with oesophagogastric adenocarcinomas has improved over the years, rates of cancer recurrence remain high. There is limited research on predictors for early recurrence (ER), especially in patients receiving FLOT chemotherapy. The aim of this study was to investigate ER and survival rates and identify risk factors of ER.

Methods

Patients receiving neoadjuvant chemotherapy with FLOT for oesophagogastric adenocarcinoma at single high-volume centre between August 2018 and October 2022 were evaluated for early recurrence defined as disease present within 1 year of surgery. Multivariable analysis was conducted to identify risk factors for ER. Patients who died in-hospital or within 90 days of surgery and those with positive longitudinal margin were excluded.

Results

169 patients were included. 92.9% and 41.4% of patients completed all four neoadjuvant and adjuvant cycles of FLOT respectively. 51 patients (30.2%) developed recurrence in the follow up period with 24 patients (14.2%) having ER. Recurrence free survival and overall survival at one year were 84.1% and 91.7% respectively. The estimated median survival after recurrence was 4.8 months. Extracapsular spread was found to be independent risk factor for ER (OR 6.507, 95% CI 1.964-21.556, p=0.002) in multivariable analyses together with ypN3 stage (OR 7.204, 95% CI 1.118-46.403, p=0.038).

Conclusions

The variables identified in this study may be helpful in determining patients at a higher risk of ER following curative surgery. Understanding these predictors may help tailor the follow up care of these patients, such as regular surveillance imaging, treatment, and frequency of reviews.
O220: The role of cardiopulmonary exercise testing in predicting sarcopenia after neoadjuvant chemotherapy and post-operative complications
Authors: Dayanamby Abbienaya , Chmelo Jakub , Convill James , Samake Maurice , Petrides George , Phillips Alexander
Published: March 2024

Background

Neoadjuvant chemotherapy (NAC) may contribute to sarcopenia development in patients with oesophageal and oesophagogastric junction (OGJ) adenocarcinoma. Preoperative cardiopulmonary fitness and sarcopenia are both variables which have been correlated with outcomes after major surgery. The aims of this study were to investigate if pre-operative cardiopulmonary exercise testing (CPET) variables were associated with radiological sarcopenia post NAC, and the effect of CPET variables on post-operative outcomes in sarcopenic patients.

Methods

Patients from a single high-volume tertiary centre diagnosed with oesophageal or OGJ adenocarcinoma between August 2015 and August 2022 were included. CPET variables and post-NAC CT scans to assess for radiological sarcopenia were evaluated. CPET variables included in statistical analyses were ventilatory equivalent for carbon dioxide (VE/VCO2), anaerobic threshold (AT) and peak oxygen consumption (VO2 peak).

Results

208 patients were included. Median VE/VCO2 was 29 in patients with sarcopenia post-NAC and 28 in non-sarcopenic patients (p = 0.009). Other CPET variables were not associated with sarcopenia post NAC. Within the sarcopenic group, CPET variables were not associated with post-operative complications. Within the whole cohort, increased VE/VCO2 or decreased VO2 peak correlated with a longer hospital stay (p=0.043 and p=0.012 respectively), and an association was observed between VE/VCO2 and Clavien-Dindo grade of complications (p=0.019).

Conclusions

VE/VCO2 was associated with sarcopenia post NAC in patients with oesophageal and OGJ adenocarcinoma. Further analysis with a larger sample size might help establish this, which could be helpful in identifying and targeting patients at higher risk of sarcopenia and post-operative complications.
O265: Laparoscopic Cholecystectomy in Class III (Morbid) Obesity
Authors: Warrell Daniel , Oh Ke En , Pessoa Luiza , Manson David , Nageswaran Haritharan
Published: March 2024

Background

High body-mass index (BMI) has been associated with increased operative-time, conversion to open surgery, and poorer perioperative outcomes. Criteria for day-surgery often includes BMI, with centers excluding patients with BMI>40kg/m2. However, as cholecystectomies are routinely performed laparoscopically with low complication rates in patients with higher BMI, this cut-off is being questioned.

Objectives

To examine outcomes of Laparoscopic Cholecystectomy in patients with increased BMI, particularly when comparing patients with morbid-obesity (Class-III;BMI>40 kg/m2) to those with lower BMI.

Methods

Data was collected between 01/01/2022 and 31/07/2023 from hospitals throughout the Aneurin-Bevan University Health-Board, South-Wales, UK. Data on BMI, surgical indication, surgical duration, length of admission, and 30-day complications, amongst others was collected.

Results

This study included a total of 915 patients, 77.92%female 22.08%male. Patients were placed into 5 BMI categories: BMI<25(n=98),25-29(n=255),30-34(n=253),35-39(n=176), and>40(n=133). Median BMI was 31kg/m2, median surgical duration was 79-minutes, length of stay 0-days, the complication rate was 7.3%. There were two 30-day mortalities, one in each of BMI categories <25 and 25-29. Comparing patients with BMI>40 with others showed a significantly higher surgical duration (median 90.05mins vs83.5mins;p=0.045) but no difference in complications including bile-leak (2.3%vs1.8%;p=0.1823), significant bleed (0.7%vs0.4%;p=0.4779) or bile-duct injury (0%vs0.1%;p=0.4060). Due to existing day-surgery criteria, there was significantly increased length of admission in this group (median 1vs0 days;p=0.00).

Conclusion

This retrospective study finds Laparoscopic Cholecystectomy safe in patients with Class-III obesity with no increased association with intraoperative or post-operative complications. Criteria for day-surgery based solely on BMI>40 appears inappropriate.
O65: Extremity Trauma in the UK (UK): Vascular Interventions and Surgery in Trauma Audit (VISTA)
Authors: Hurndall Katherine-Helen , Leatherby Robert , Tai Nigel , Glasgow Simon , Davenport Ross
Published: March 2024

Background

Extremity injury is the commonest form of vascular trauma but currently there is no national surgical surveillance of operative management and amputation rates. Vascular injury impacts both the young and elderly, with time critical, trauma specific intervention key for limb salvage.

Methods

Subgroup analysis of a six-month multicentre, prospective audit of vascular injuries to examine procedures for extremity vascular trauma at 27 UK Major Trauma Centres conducted by the National Trauma Research & Innovation Collaborative and Vascular & Endovascular Research Network.

Results

There were 153 extremity vascular injuries (n=120 patients: 66 upper limb, 81 lower limb) with 92 primary interventions performed (n=86 open: primary repair, bypass or ligation vs. n=6 endovascular). The median age of operated patients was 36 (IQR: 22.5 - 52) years and 74% were male. 51% of injuries operated upon were secondary to blunt trauma with concomitant orthopaedic injury in 33%. Median time to intervention was 169 (IQR: 112 - 371) minutes with a consultant vascular surgeon present in 84% of cases. Overall, there were n=16 amputations: 7% primary and 11% secondary in operative cases. The median age for amputation was 41.5 (IQR: 36 - 52) years.

Conclusion

Extremity vascular interventions, regardless of aetiology, require national surveillance to assess outcomes and identify targets for improved limb salvage across all UK vascular and trauma networks.
O166: Safety and Efficacy of Autologous Fat Grafting in the Treatment of Radiation-Induced Fibrosis and Contour Defects in Head and Neck Reconstruction
Authors: Langridge Benjamin , Abul Ahmad , Nagra Raveenjot , Awad Laura , Jasionowska Sara , Bollen Edward , Frommer Marvin , Sinha Deepti , Thompson Anna , Kalavrezos Nicholas , Butler Peter
Published: March 2024

Background

Multimodal treatment for head and neck cancer results in significant functional and cosmetic morbidity, often through contour deformity and radiation-induced skin fibrosis (RIF), affecting head and neck function and cosmesis. Autologous fat grafting is an emerging treatment for RIF. We conducted a retrospective cohort review of patient outcomes following autologous fat transfer for reconstruction of head and neck contour deformity and RIF.

Methods

A retrospective analysis was performed of patients treated at 2 UK centres between 2009-2022. Patient data collated included demographics, oncological treatment, reconstruction, operative details, and pre- and post-operative patient reported outcome measures (PROMs) including University of Washington Quality of Life Questionnaire (UW-QOL), Derriford Appearance Scale (DAS24) and Patient Outcomes of Surgery (POS). Patients were stratified by indication for AFG.

Results

A total of 45 patients were identified. 89% of patients (85% RIF, 92% contour deformity) reported cosmetic or functional improvement. Two patients (4%) reported no improvement, and three (7%) were lost to follow-up. Psychological health scores improved in patients following AFG for both RIF and contour deformity patients (DAS24, P< 0.0001). The UW-QOL scores revealed statistically significant improvements in multiple functional domains including appearance, activity, recreation, mood, and anxiety in both patients with RIF and contour deformities.

Conclusion

This study demonstrates that AFG is an effective technique for the correction of contour deformity and RIF in patients following treatment for head and neck cancer. Patients suffering from RIF demonstrated significant improvements in both functional and psychological domains.
O87: Stratified Evaluation of Large Language Model GPT-4’s Question-Answering In Surgery reveals AI Knowledge Gaps
Authors: Lonergan Rebecca Murphy , Curry Jake , Dhas Kallpana , Simmons Benno
Published: March 2024

Introduction

Large Language Models (LLMs), such as GPT, are artificial intelligence models designed to analyse vast data and generate coherent outputs, changing the way healthcare professionals access knowledge. Critically, LLMs also present incorrect information confidently, a phenomenon known as hallucination, which is particularly dangerous in the safety-critical field of medicine. The validity of LLM responses to medical queries are being explored generally, however, responses to surgical questions remain poorly quantified. Variations between specialties are important to identify to support strategic LLM improvements.

Methods

We assessed accuracy of GPT-3 and GPT-4 in answering surgical multi-choice questions from the MedMCQA post-graduate question bank. We calculated the percentage accuracy of GPT-4 on all surgical questions (n=23025) and compared this to published GPT-4 performance across the whole MedMCQA dataset. We also analysed variations in performance by topic on a randomised sample of questions manually sorted by surgical specialty (n=1000).

Results

Accuracy rates for GPT-3 and GPT-4 were 53% and 64% respectively, demonstrating significant superiority of GPT-4, however GPT-4's surgical performance remained weaker than its overall MedMCQA performance. Notably, accuracy varied significantly by specialty, with strong performances in anatomy, vascular and paediatric surgery but below-average performances in orthopaedics, ENT and neurosurgery.

Conclusion

This study holds significant implications for the expanding use of LLMs in surgery, especially education. GPT has improved accuracy with sequential developments, however, its performance requires further scrutiny. We recommend ongoing attention on factors underpinning subject-variation in performance to aid strategic LLM innovation.
O162: A Surgically Led Quality Improvement Initiative in Surgical Antibiotic Prophylaxis (SAP): A One-year Review of Practice and Change in an Irish Context
Authors: Giblin Katie , Hill Gerard , Weir Niamh , Gash Sadhbh , Bagwe Isha , Stapleton Alex , Stevens Niall , Hill Arnold
Published: March 2024

Introduction

Amongst growing concerns of antimicrobial resistance, surgical site infection (SSI) remains one of the most common healthcare associated infections. Optimal use of Surgical Antibiotic Prophylaxis (SAP) is critical. Quality Improvement (QI) in this area is often led by pharmacists or infection specialists.

Methods

A two-year, surgically led QI initiative was established in two Irish hospitals in July 2022. Baseline level of compliance with local guidelines with regard four aspects of SAP (indication, agent, timing, and duration) was audited. Change interventions aimed at specific aspects of compliance were trialled. Interventions included; guideline education for prescribers, process changes (editing the sign in/time out sheet) and the application of prescribing nudges (antibiotic duration sticker in post-operative drug chart).

Results

A total of 620 patient records were audited over one year. Pre-intervention compliance with all four aspects of SAP was observed in only 72/303 patients (23.7%). Educational interventions with surgical prescribers led to improved compliance with agent choice (43.5% (71/165) to 65.3% (94/144)). Education of anaesthetists showed improved timing of administration with 10.8% (14/129) of SAP administered post-incision post-intervention compared to 18.9% (21/111) pre-intervention. Application of the SAP duration sticker showed an overall decrease in mean SAP duration from 70.4 hours to 28.2 hours in those patients requiring more than a single SAP dose. Overall compliance levels have improved, thus far, from 23.7% to 39.8%.

Conclusion

Increasing compliance with SAP guidance is a challenge. A multi-faceted, institution specific, surgically led approach grounded in QI methodology shows promise.
O120: Knowledge and perceptions of General and Vascular surgeons and the public on antibiotic resistance: a validated questionnaire study
Authors: Kutyla Kamila , Lam Kyle , Acharya Amish
Published: March 2024

Introduction

Antibiotic resistance is a leading cause of death globally. Surgeons are responsible for a significant proportion of antibiotic prescribing with surgical prophylaxis constituting 15% of all antibiotic prescriptions. Despite this, knowledge and perceptions of surgeons surrounding antibiotic resistance are poorly understood and therefore antibiotic stewardship programmes have failed to target this cohort of prescribers.

Methods

Two parallel surveys were created and distributed to surgeons (n=48) and the public (n=115). Content validity was ensured through a systematic review of the literature. Clinical scenarios testing antimicrobial prescribing practice were included in the surgeon survey. Both surveys were further validated by a multidisciplinary panel of surgeons and consultant microbiologists. A multimodal distribution approach was utilised including face-to-face, email, and patient and public engagement platforms.

Results

Surgeons scored poorly across knowledge domains with 7/9 clinical scenarios answered correctly by less than 50% of participants. Key barriers to adequate prescribing identified were knowledge/education, fear of missing an infection, guidelines, and cultural issues. The most useful interventions identified were formal education to prescribers (70.8%), provision of local antibiotic resistance patterns (64.7%) and increased help from Infectious Diseases/Microbiology/Pharmacy (64.7%). Although public participants demonstrated good knowledge surrounding antibiotic use and antimicrobial resistance, medical professionals were reported to be their major information source.

Conclusion

Surgeon knowledge surrounding antimicrobial resistance can be improved through targeted antibiotic stewardship interventions and addressing barriers identified by this study. Although public participants surveyed demonstrate willingness to improve antibiotic use, behaviour change will be predominantly driven by improved practice by surgeons.
O6: Trends in the mortality, incidence, and disability-adjusted life-years of intestinal obstruction and paralytic ileus: an observational study of the Global Burden of Disease database
Authors: Proctor Dominic , Goodall Richard , Borsky Kim , Salciccioli Justin , Marshall Dominic , Mohamed Abdulla , Shanmugarajah Kumaran , Shalhoub Joseph
Published: March 2024

Background

Intestinal obstruction and paralytic ileus place a substantial burden on global healthcare systems despite its aetiology often being amenable to preventative healthcare interventions. Further characterisation of the disease burden in EU15+ countries may help optimise the delivery of healthcare services. This observational analysis assessed the trends in mortality and incidence of intestinal obstruction and paralytic ileus in European Union (EU) 15+ countries between the years 1990 and 2019.

Methods

Sex-specific age-standardised mortality rates (ASMRs), age-standardised incidence rates (ASIRs) and disability-adjusted life years (DALYs) data for intestinal obstruction and paralytic ileus were extracted from the 2019 Global Burden of Disease (GBD) study. Temporal trends across the observation period were analysed using Joinpoint regression analysis.

Results

The median ASMRs across EU15+ countries in 2019 were 1.96/100,000 and 2.16/100,000 for females and males, respectively. Between 1990 and 2019 the median percentage change in ASMR was -8.11% for females and +5.50% in males. The median ASIRs in 2019 for females and males were 150/100,000 and 133/100,000, respectively, with a median percentage change of +18.7% for females and +15.3% for males during the observation period. Decreasing trends in DALYs were observed over the 30-year study period, with median percentage changes of -11.86% and -5.80% for females and males, respectively.

Conclusion

Overall, increasing ASIRs of intestinal obstruction/paralytic ileus were observed across EU15+ countries, with modest overall decreases in ASMRs. Variations in both diagnostic and management strategies for intestinal obstruction/paralytic ileus over the observation period are likely contributors to the changing disease burden.
O188: Progressive specialisation within General Surgery and minimally invasive techniques: how can we prepare today's surgeons for humanitarian work?
Authors: Walsh Nadia , Maitra Sulagna , Wladis Andreas , O’Sullivan Cliona
Published: March 2024

Background

General surgery has evolved from training a surgeon who was able to perform a variety of procedures to an increase in subspecialists and the narrowing of the specialty’s scope of practice. In contrast, the humanitarian field still demands a broad trained specialist who can work with limited resources, adapted to the cultural context. The present study aimed to explore this gap and propose solutions to the existing problem.

Methods

Qualitative approach using one-to-one semi-structured interviews with surgeons with various levels of experience in the humanitarian field.

Results

Thirteen humanitarian surgeons were interviewed. The main challenges of working in humanitarian environments were limited resources, diverse pathology or distinct presentation of common pathology, lack of referral systems and the decision-making process per se. The field demands a broad trained surgeon with experience in emergency procedures in various subspecialties. The learning process in the ground is more practical than the formal surgical education, therefore, adequate preparation is required prior to deployment. Individual and systemic approaches were suggested by the participants for training of surgeons, although barriers are still numerous. Surgeons who plan to have a humanitarian career must identify the gaps in their training and fulfil them accordingly, and organisations must take approaches to aid surgeons to satisfy these requirements.

Conclusions

There is urgent need to develop formal mechanisms of training and to ensure quality of care through professionalization of humanitarian surgery. Collaboration between organisations and leadership are essential for the establishment of training programmes and for the future of humanitarian surgery.
O97: Long term outcomes after negative appendicectomy: does morbidity justify mandatory pre-operative confirmation of appendicitis prior to surgery?
Authors: Hammett Felix , Ghoneima Ahmed , Nasir Uzair , Saha Arin
Published: March 2024

Introduction

Negative appendicectomy is sometimes described as a quality indicator of an acute surgical service. Previous studies have suggested that negative appendicectomy carries an unacceptably high risk of morbidity and advocate pre-operative imaging to confirm a diagnosis in all cases, despite the resource implications this policy carries. This study quantified long term morbidity after negative appendicectomy.

Methods

This retrospective cohort study identified all patients who underwent appendicectomy for suspected appendicitis from June 2010 to August 2015 at a single centre. Patients with a histologically normal appendix were identified and their notes were interrogated to record outcomes; median follow-up was 10.6 (range, 8 – 13) years. Complications after surgery were classified using the Clavien-Dindo system.

Results

1914 patients had an appendicectomy. 181 patients (9.5%) had a negative appendicectomy. There were 40 re-admissions after surgery; half (20 patients) were within 30 days. The most common causes of re-admission were ongoing symptoms with no identifiable cause (15 patients, 37.5%) or post-operative pain (9 patients (22.5%). Overall post-operative complication rate was 11 patients (6.1%). Of these, 6 patients had Grade 1 or 2 complications, 5 patients (3%) had Grade 3 complications (return to theatre for infection, bleeding or hernia) and none had Grade 4 or 5 complications. There was no mortality.

Conclusions

There is low short- and long-term morbidity after negative appendicectomy which suggests that routine pre-operative imaging to confirm a diagnosis of appendicitis before surgery is unwarranted. The concerns around complications after negative appendicectomy appear unjustified and should not be a quality indicator.
O123: External peri-stomal skin granulations in paediatric tracheostomy: incidence, outcomes and a proposed treatment algorithm
Authors: Kawar Luai
Published: March 2024

Background

External peri-stomal skin granulations after tracheostomy in children are common and may interfere with routine tube changes. This study is the first attempt to describe the incidence and outcomes, along with a proposed treatment algorithm.

Methods

A retrospective review of all inpatient children with a tracheostomy between January 2020 and May 2022 at the Royal Hospital for Children (RHC) in Glasgow. The presence of external peri-stomal granulation, date of onset and resolution, recurrence and treatment modalities were noted.

Results

A total of 50 episodes of peri-stomal granulation were identified in 27 children (52%). Median age at the end of the study period was 4.3 years, with younger children experiencing more frequent granulation. 3 episodes interfered with tracheostomy tube changes. Time to resolution of the granulation was significantly longer with topical steroid/antimicrobial ointment monotherapy, but recurrence was less common when this was used a first treatment modality.

Conclusion

Non-invasive measures such as topical anti-microbials should be used in the first instance when managing external stoma-site granulations. More invasive measures, such as silver nitrate cautery and surgical excision, should be considered if the granulation tissue is not improving or when it poses a risk to safe tube changes.
O209: Stress-induced extracellular vesicles promote EGFR-ERK dependent growth and cetuximab resistance in colorectal cancer
Authors: Mason John , Marks Ewan , Fan Shih-Jung , Wilson Clive , Hamdy Freddie , Harris Adrian , Cunningham Chris , Goberdhan Deborah
Published: March 2024

Introduction

Extracellular vesicles (EVs) are nanoized vesicles, which deliver bioactive cargoes to target cells. Our lab has shown that metabolic stress leads to changes in the trafficking and also the cargo and functions of EVs secreted from colorectal cancer (CRC) cells: a so-called “EV switch”. Proteomic analysis revealed that switched EVs carry increased levels of the EGFR-ligand Amphiregulin (AREG). The aim of this work was to investigate the pro-tumorigenic properties of switched EVs in vitro and in vivo.

Methods

Size exclusion chromatography was used to isolate EVs from HCT116 and Caco-2 CRC cells grown under glutamine-replete and -depleted conditions, and their effect on recipient cell growth measured using the IncuCyte Live Cell Imager. Co-incubation assays with an AREG-neutralising antibody were undertaken to test the role of switched EVs. The in vivo role of switched EVs were investigated using a novel chick embryo model. In addition, we tested whether the growth inhibitory effects of cetuximab could be reversed by co-treatment with switched EVs.

Results

Switched EVs from HCT116 and Caco-2 cells contain increased levels of AREG and promote EGFR-ERK dependent growth in recipient cells in vitro and in vivo. These effects were inhibited by co-treatment with an AREG neutralising antibody. Caco-2 (KRAS-wild type), but not HCT116 (KRAS-mutant), cell growth was inhibited by cetuximab, which was partially reversed by co-treatment with switched EVs. AREG neutralisation reversed this EV-induced cetuximab rescue.

Conclusion

Switched EVs mediate CRC cell growth and cetuximab resistance, and could serve as novel biomarkers to predict treatment response.