Rxivist logo

Rxivist combines biology preprints from bioRxiv and medRxiv with data from Twitter to help you find the papers being discussed in your field. Currently indexing 150,977 papers from 635,984 authors.

Most downloaded biology preprints, since beginning of last month

in category surgery

103 results found. For more information, click each entry to expand.

61: A hemodynamic model to predict regional cerebral blood flow and blood flow reserve in patients with carotid stenosis
more details view paper

Posted 22 Jul 2020

A hemodynamic model to predict regional cerebral blood flow and blood flow reserve in patients with carotid stenosis
22 downloads medRxiv surgery

joseph p archie

Joseph P Archie Jr, PhD, MD Abstract Purpose. Patients with 50% or greater diameter stenosis are at risk for ischemic stroke due to embolization and/or reduced cerebral blood flow. The hemodynamics of progressive carotid stenosis on cerebral blood flow and blood flow reserve has not been adequately measured or predicted. This information is needed for stroke risk stratification in patients with carotid stenosis. The aim of this hemodynamic model study is to predict the contribution of carotid and collateral blood flows to regional cerebral blood flow and cerebral blood flow reserve in patients with moderate to severe carotid stenosis. Methods. A one-dimensional three-parameter fluid mechanics model for the carotid, collateral and brain vascular systems is used to predict regional cerebral blood flow and blood flow reserve as a function of percent diameter carotid stenosis. The model is based on the principal of conservation of energy as employed by Bernoulli to describe fluid flow on a streamline. When applied to the human cerebrovascular system there are three vascular resistance components; carotid, collateral and brain. Carotid artery vascular resistance is assumed to be a function of fractional percent carotid artery area stenosis. This is not a complex modern computational fluid mechanics study. The model blood flow algebraic equations have simple solutions, one of which gives patient specific collateral resistance values. The solutions are given as patient specific cerebral blood flows and flow reserve as a function of percent diameter stenosis. Established normal clinical values of regional cerebral blood flow, cerebral blood flow auto-regulation and the lower threshold of cerebral perfusion pressure for cerebral auto-regulation are used. Carotid vascular resistance is assumed to be proportional to percent area carotid stenosis. Theoretical solutions use mean systemic arterial pressure of 100mmHg and key clinical values of patient collateral vascular resistance. Clinical solutions use patient measured systemic arterial pressures and carotid stump pressures. The solutions are given as patient specific cerebral blood flow and reserve cerebral blood flow curves over the range of diameter carotid stenosis. Results. Normal regional cerebral blood flow of 50ml/min/100g is predicted to be maintained up to 65% diameter carotid stenosis as reserve blood flow is reduced. With further progression of carotid stenosis to occlusion approximately half of patients are predicted to develop some reduction in cerebral blood flow. However, only about 20% of patients have a decrease in cerebral blood flow below the 30ml/min/100g threshold for cerebral ischemic symptoms. Approximately 10% of patients are predicted to develop regional cerebral blood flow less than the 18ml/min/100g threshold for irreversible ischemic injury. The model predicts critical carotid artery stenosis to be between 65% and 71% diameter depending on mean systemic arterial pressure. With higher degrees of stenosis carotid artery blood flow cannot maintain normal cerebral flow without the contribution of collateral flow. The predicted magnitude of carotid energy dissipation between 60% and 90% stenosis is consistent with observed cervical bruit intensity. Predicted patient specific cerebral blood flow reserve is adequate to prevent significant cerebral ischemia in the majority of patients. Conclusions. Patient specific collateral vascular resistance blood flow curves predict regional cerebral blood flow and blood flow reserve as a function of the degree of diameter carotid artery stenosis. The carotid component of cerebral blood flow is predicted to maintain normal cerebral blood flow up to a critical carotid diameter stenosis of 65% to 71%. Collateral blood flow is necessary to maintain normal cerebral flow at higher degrees of carotid stenosis. The clinical model predicts that many patients do not have sufficient collateral flow to prevent a decrease in cerebral flow should carotid stenosis progress to high grade or occlusion. However, only about 10% of patients are predicted to develop irreversible regional cerebral ischemic injury. Estimated carotid stenosis energy dissipation magnitudes agree with observed cervical bruit intensity. Correlation of predicted cerebral reserve blood flow curves with clinically measured cerebrovascular reactivity/reserve has the potential to predict the probability of future cerebral ischemia in asymptomatic patients with 60% to 80% stenosis.

62: Efficacy and safety of erythropoietin for traumatic brain injury: a meta-analysis of randomized controlled trials
more details view paper

Posted 23 Sep 2019

Efficacy and safety of erythropoietin for traumatic brain injury: a meta-analysis of randomized controlled trials
22 downloads medRxiv surgery

Motao Liu, Amy J. Wang, Gexin Zhao, Hua He, Ziv M Williams, Kejia Hu

ObjectiveRecent studies regarding the effects of erythropoietin (EPO) for treating traumatic brain injury (TBI) have been inconsistent. This study conducts a meta-analysis of randomized controlled trials (RCTs) to assess the safety and efficacy of EPO for TBI patients at various follow-up time points. MethodsA literature search was performed using PubMed, Web of Science, MEDLINE, Embase, Google Scholar and the Cochrane Library for RCTs studying EPO in TBI patients published through March 2019. Non-English manuscripts and non-human studies were excluded. The assessed outcomes include mortality, neurological recovery and associated adverse effects. Dichotomous variables are presented as risk ratios (RR) with a 95% confidence interval (CI). ResultsA total of seven RCTs involving 1197 TBI patients were included in this study. Compared to the placebo arm, treatment with EPO did not improve acute hospital mortality or short-term mortality. However, there was a significant improvement in mid-term (6 months) follow-up survival rates. EPO administration was not associated with neurological function improvement. Regarding adverse effects, EPO treatment did not increase the incidence of thromboembolic events or other associated adverse events. ConclusionsThis meta-analysis indicates a slight mortality benefit for TBI patients treated with EPO at mid-term follow-up. EPO does not improve in-hospital mortality, nor does it increase adverse events including thrombotic, cardiovascular and other associated complications. Our analysis did not demonstrate a significant beneficial effect of EPO intervention on the recovery of neurological function. Future RCTs are required to further characterize the use of EPO in TBI.

63: Post-operative serum procalcitonin vs C reactive Protein as a marker of post-operative infectious complications in pancreatic surgery. A systemic review and metaanalysis.
more details view paper

Posted 09 Oct 2020

Post-operative serum procalcitonin vs C reactive Protein as a marker of post-operative infectious complications in pancreatic surgery. A systemic review and metaanalysis.
21 downloads medRxiv surgery

Bhavin Vasavada, Hardik Patel

Aim of StudyAim of this meta-analysis was to compare diagnostic accuracy of C reactive Protein and Procalcitonin between postoperative day 3 to 5 in predicting infectious complications post pancreatic surgery. MethodsSystemic literature search was performed using MEDLINE, EMBASE and SCOPUS to identify studies evaluating the diagnostic accuracy of Procalcitonin (PCT) and C-Reactive Protein (CRP) as a predictor for detecting infectious complications between postoperative days (POD) 3 to 5 following pancreatic surgery. A meta-analysis was performed using random effect model and pooled predictive parameters. Geometric means were calculated for PCT cut offs. The work has been reported in line with PRISMA guidelines. ResultsAfter applying inclusion and exclusion criteria 15 studies consisting of 2212 patients were included in the final analysis according to PRISMA guidelines. Pooled sensitivity, specificity, Area under curve and diagnostic odds ratio (DOR)for day 3 C-reactive protein was respectively 62%,67% 0.772 and 6.54. Pooled sensitivity, specificity, Area under curve and diagnostic odds ratio (DOR)for day 3 procalcitonin was respectively 74%,79%,0.8453 and 11.03. Sensitivity, specificity, Area under curve, and Diagnostic odds ratio for day 4 C-reactive protein was respectively 60%,68%, 0.8022 and 11.90. Pooled Sensitivity, specificity and Diagnostic odds ratio of post-operative day 5 procalcitonin level in predicting infectious complications were respectively 83%,70% and 12.9. Pooled Sensitivity, specificity, AUROC and diagnostic odds ratio were respectively 50%,70%, 0.777 and 10.19. ConclusionPost-operative procalcitonin is better marker to predict post-operative infectious complications after pancreatic surgeries and post-operative day 3 procalcitonin has highest diagnostic accuracy.

64: Machine learning to predict early recurrence after oesophageal cancer surgery
more details view paper

Posted 03 Jul 2019

Machine learning to predict early recurrence after oesophageal cancer surgery
21 downloads medRxiv surgery

Saqib A Rahman, Robert C Walker, Megan A Lloyd, Ben L Grace, Gijs I van Boxel, Feike Kingma, Jelle P. Ruurda, Richard van Hillegersberg, Scott Harris, Simon Parsons, Stuart Mercer, Ewen A Griffiths, J.Robert O’Neill, Richard Turkington, Rebecca C Fitzgerald, Timothy J Underwood, On behalf of the OCCAMS Consortium, the full list of contributors is displayed in acknowledgements

ObjectiveTo develop a predictive model for early recurrence after surgery for oesophageal adenocarcinoma using a large multi-national cohort. Summary Background DataEarly cancer recurrence after oesophagectomy is a common problem with an incidence of 20-30% despite the widespread use of neoadjuvant treatment. Quantification of this risk is difficult and existing models perform poorly. Machine learning techniques potentially allow more accurate prognostication and have been applied in this study. MethodsConsecutive patients who underwent oesophagectomy for adenocarcinoma and had neoadjuvant treatment in 6 UK and 1 Dutch oesophago-gastric units were analysed. Using clinical characteristics and post-operative histopathology, models were generated using elastic net regression (ELR) and the machine learning methods random forest (RF) and XG boost (XGB). Finally, a combined (Ensemble) model of these was generated. The relative importance of factors to outcome was calculated as a percentage contribution to the model. ResultsIn total 812 patients were included. The recurrence rate at less than 1 year was 29.1%. All of the models demonstrated good discrimination. Internally validated AUCs were similar, with the Ensemble model performing best (ELR=0.785, RF=0.789, XGB=0.794, Ensemble=0.806). Performance was similar when using internal-external validation (validation across sites, Ensemble AUC=0.804). In the final model the most important variables were number of positive lymph nodes (25.7%) and vascular invasion (16.9%). ConclusionsThe derived model using machine learning approaches and an international dataset provided excellent performance in quantifying the risk of early recurrence after surgery and will be useful in prognostication for clinicians and patients. DRAFT VISUAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=110 SRC="FIGDIR/small/19001073v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@2f60b7org.highwire.dtl.DTLVardef@76bfb6org.highwire.dtl.DTLVardef@2469deorg.highwire.dtl.DTLVardef@a27d47_HPS_FORMAT_FIGEXP M_FIG C_FIG Icons taken from www.flaticon.com, made by Freepik, smashicons, and prettycons. Reproduced under creative commons attribution license MINI-ABSTRACTEarly recurrence after surgery for adenocarcinoma of the oesophagus is common. We derived a risk prediction model using modern machine learning methods that accurately predicts risk of early recurrence using post-operative pathology

65: Study protocol for COvid-19 Vascular sERvice (COVER) study: The impact of the COVID-19 pandemic on the provision, practice and outcomes of vascular surgery
more details view paper

Posted 29 May 2020

Study protocol for COvid-19 Vascular sERvice (COVER) study: The impact of the COVID-19 pandemic on the provision, practice and outcomes of vascular surgery
21 downloads medRxiv surgery

Vascular and Endovascular Research Network, Ruth A Benson, Dave C Bosanquet, Sandip Nandhra, Joseph Shalhoub, Athanasios Saratzis, Rachel Forsythe, Sarah Onida, George Dovell, Louise Hitchman, Nikesh Dattani, Ryan Preece, Graeme K Ambler, Christopher Imray

Background: The novel Coronavirus Disease 2019 (COVID-19) pandemic is having a profound impact on global healthcare. Shortages in staff, operating theatre space and intensive care beds has led to a significant reduction in the provision of surgical care. Even vascular surgery, often insulated from resource scarcity due to its status as an urgent specialty, has limited capacity due to the pandemic. Furthermore, many vascular surgical patients are elderly with multiple comorbidities putting them at increased risk of COVID-19 and its complications. There is an urgent need to investigate the impact on patients presenting to vascular surgeons during the COVID-19 pandemic. Methods and Analysis: The COvid-19 Vascular sERvice (COVER) study has been designed to investigate the worldwide impact of the COVID-19 pandemic on vascular surgery, at both service provision and individual patient level. COVER is running as a collaborative study through the Vascular and Endovascular Research Network (VERN) with the support of numerous national (Vascular Society of Great Britain and Ireland, British Society of Endovascular Therapy, British Society of Interventional Radiology, Rouleaux Club) and an evolving number of international organisations (Vascupedia, SingVasc, Audible Bleeding (USA), Australian and New Zealand Vascular Trials Network (ANZVTN)). The study has 3 Tiers: Tier 1 is a survey of vascular surgeons to capture longitudinal changes to the provision of vascular services within their hospital; Tier 2 captures data on vascular and endovascular procedures performed during the pandemic; and Tier 3 will capture any deviations to patient management strategies from pre-pandemic best practice. Data submission and collection will be electronic using online survey tools (Tier 1: SurveyMonkey for service provision data) and encrypted data capture forms (Tiers 2 and 3: REDCap for patient level data). Tier 1 data will undergo real-time serial analysis to determine longitudinal changes in practice, with country-specific analyses also performed. The analysis of Tier 2 and Tier 3 data will occur on completion of the study as per the pre-specified statistical analysis plan. Ethical Approval: Ethical approval from the UK Health Research Authority has been obtained for Tiers 2 and 3 (20/NW/0196 Liverpool Central). Participating centres in the UK will be required to seek local research and development approval. Non-UK centres will need to obtain a research ethics committee or institutional review board approvals in accordance with national and/or local requirements. ISRCTN: 80453162 (https://doi.org/10.1186/ISRCTN80453162) Ethical Approval: 20/NW/0196 Liverpool Central, IRAS: 282224

66: The global impact of the first Coronavirus Disease 2019 (COVID-19) pandemic wave on vascular services
more details view paper

Posted 17 Jul 2020

The global impact of the first Coronavirus Disease 2019 (COVID-19) pandemic wave on vascular services
21 downloads medRxiv surgery

Vascular and Endovascular Research Network, Ruth A Benson, Sandip Nandhra

Background: The Coronavirus Disease 2019 (COVID-19) pandemic is having an unprecedented impact on healthcare delivery. This international qualitative study captured the global impact on vascular patient care during the first pandemic wave. Methods: An online structured survey was used to collect regular unit-level data regarding the modification to a wide range of vascular services and treatment pathways on a global scale. Results: The survey commenced on 23rd March 2020 worldwide. Over six weeks, 249 vascular units took part in 53 countries (465 individual responses). Overall, 65% of units stopped carotid surgery for anyone except patients with crescendo symptoms or offered surgery on a case-by-case basis, 25% only intervened for symptomatic aortic aneurysms cancelling all elective repairs. For patients with symptomatic peripheral arterial disease 60% of units moved to an endovascular-first strategy. For patients who had previously undergone endovascular aortic aneurysm repair, 31.8% of units stopped all postoperative surveillance. Of those units regularly engaging in multidisciplinary team meetings, 59.5% of units stopped regular meetings and 39.1% had not replaced them. Further, 20% of units did not have formal personal protective equipment (PPE) guidelines in place and 25% reported insufficient PPE availability. Conclusions: The COVID-19 pandemic has had a major impact on vascular services worldwide. There will be a significant vascular disease burden awaiting screening and intervention after the pandemic.

67: Predictive value of Altmetric Score on prospective citation and bibliometric impact: rise of a new argot
more details view paper

Posted 20 May 2020

Predictive value of Altmetric Score on prospective citation and bibliometric impact: rise of a new argot
20 downloads medRxiv surgery

David BT Robinson, Arfon G Powell, Jennifer Waterman, Luke G Hopkins, Osian P James, Richard J Egan, Wyn G Lewis

Background Bibliometric and Altmetric analyses provide important but alternative perspectives regarding research article impact. This study aimed to establish whether Altmetric Score (AS) was associated with citation rate, independent of bibliometrics. Method Citations for a previously reported cohort of 100 most cited articles associated with the keyword Surgery (2018, Powell et al), were collected and a three year interval Citation Gain (iCG) evaluated. Previous citation count, Citation Rate Index (CRI), AS, five year Impact Factor, and Oxford Centre for Evidence Based Medicine (OCEBM) levels were used to classify citation rate prospect. Results During follow-up, the median iCG was 161 (IQR 83 to 281), with 73 and 62 articles receiving an increase in CRI and AS, respectively. Median CRI and AS increase were 2.8 (-0.1 to 7.7) and 3 (0 to 4), respectively. Receiver Operator Characteristic (ROC) analysis revealed that CRI (AUC 0.86 (95% CI 0.79 to 0.93), p<0.001) and AS (Area Under Curve (AUC) 0.65 (95% CI 0.55 to 0.76), p=0.008) were associated with higher iCG. AS critical threshold greater than or equal to 2.0 was associated with better iCG when dichotomised at iCG median (OR=4.94, 95% CI 1.99 to 12.26, p=0.001) and iCG Upper Quartile (UQ, OR=4.13, 95% CI 1.60 to 10.66, p=0.003). Multivariable analysis identified that only CRI was independently associated with iCG when dichotomised at the median (OR 18.22, 95% CI 6.70 to 49.55, p<0.001) and UQ (OR 19.30, 95% CI 4.23 to 88.15, p<0.001). Conclusion Citation Rate Indices and Altmetric Scores are important predictors of interval Citation Gain, and better at predicting future citations than the historical and established Impact Factor and OCEBM quality of evidence descriptors.

68: Distinguish Coronavirus Disease 2019 Patients in General Surgery Emergency by CIAAD Scale: Development and Validation of a Prediction Model Based on 822 Cases in China
more details view paper

Posted 23 Apr 2020

Distinguish Coronavirus Disease 2019 Patients in General Surgery Emergency by CIAAD Scale: Development and Validation of a Prediction Model Based on 822 Cases in China
20 downloads medRxiv surgery

Bangbo Zhao, Yingxin Wei, Wenwu Sun, Cheng Qin, Xingtong Zhou, Zihao Wang, Tianhao Li, Hongtao Cao, Weibin Wang, Yujun Wang

IMPORTANCE In the epidemic, surgeons cannot distinguish infectious acute abdomen patients suspected COVID-19 quickly and effectively. OBJECTIVE To develop and validate a predication model, presented as nomogram and scale, to distinguish infectious acute abdomen patients suspected coronavirus disease 2019 (COVID-19). DESIGN Diagnostic model based on retrospective case series. SETTING Two hospitals in Wuhan and Beijing, China. PTRTICIPANTS 584 patients admitted to hospital with laboratory confirmed SARS-CoV-2 from 2 Jan 2020 to15 Feb 2020 and 238 infectious acute abdomen patients receiving emergency operation from 28 Feb 2019 to 3 Apr 2020. METHODS LASSO regression and multivariable logistic regression analysis were conducted to develop the prediction model in training cohort. The performance of the nomogram was evaluated by calibration curves, receiver operating characteristic (ROC) curves, decision curve analysis (DCA) and clinical impact curves in training and validation cohort. A simplified screening scale and managing algorithm was generated according to the nomogram. RESULTS Six potential COVID-19 prediction variables were selected and the variable abdominal pain was excluded for overmuch weight. The five potential predictors, including fever, chest computed tomography (CT), leukocytes (white blood cells, WBC), C-reactive protein (CRP) and procalcitonin (PCT), were all independent predictors in multivariable logistic regression analysis (p[&le;]0.001) and the nomogram, named COVID-19 Infectious Acute Abdomen Distinguishment (CIAAD) nomogram, was generated. The CIAAD nomogram showed good discrimination and calibration (C-index of 0.981 (95% CI, 0.963 to 0.999) and AUC of 0.970 (95% CI, 0.961 to 0.982)), which was validated in the validation cohort (C-index of 0.966 (95% CI, 0.960 to 0.972) and AUC of 0.966 (95% CI, 0.957 to 0.975)). Decision curve analysis revealed that the CIAAD nomogram was clinically useful. The nomogram was further simplified into the CIAAD scale. CONCLUSIONS We established an easy and effective screening model and scale for surgeons in emergency department to distinguish COVID-19 patients from infectious acute abdomen patients. The algorithm based on CIAAD scale will help surgeons manage infectious acute abdomen patients suspected COVID-19 more efficiently.

69: Data Visualization for Surgical Informed Consent to Communicate Personalized Risks and Patient Preferences
more details view paper

Posted 27 Mar 2020

Data Visualization for Surgical Informed Consent to Communicate Personalized Risks and Patient Preferences
20 downloads medRxiv surgery

Undina Gisladottir, Drashko Nakikj, Rashi Jhunjhunwala, Gabriel Brat, Nils Gehlenborg

STRUCTURED ABSTRACTO_ST_ABSObjectiveC_ST_ABSIdentify key elements of an effective visualization method for communicating personalized surgical risks to patients. BackgroundCurrently, there is no consensus on which risks should be communicated during the informed consent process and how. Furthermore, patient preferences are often not considered during the consent process. These inefficiencies can lead to non-beneficial outcomes and raise the potential for legal implications. To address the limitations of the informed consent process, we propose a visual consent tool (VCT) that incorporates patient preferences and communicates personalized risks to patients using data visualization. MethodsTo understand how patients perceive risk visualizations and their role in the informed consent discussion, we gathered feedback on visualizations by conducting semi-structured interviews during postoperative visits. Thematic analysis was performed to identify major themes. Iterative evaluation and consolidation of the major themes were performed with domain experts. ResultsA total of 20 patients were interviewed for this study with a median age of 59 (sd = 14). The thematic analysis revealed factors that influence the perception of risk, of risk visualizations, and the usefulness of the proposed VCT. We found that patients preferred VCT over the current methods and had different preferences for risk visualization. Further, our findings suggest that surgical concerns of patients were not in line with existing risk calculators. ConclusionWe were able to identify key elements that influence effective risk communication in the perioperative setting. We found that patient preference is variable and should influence choices for risk presentation and visualization.

70: FREQUENCY OF INFECTION AFTER CEREBROSPINAL FLUID SHUNTING PROCEDURES
more details view paper

Posted 06 Apr 2020

FREQUENCY OF INFECTION AFTER CEREBROSPINAL FLUID SHUNTING PROCEDURES
19 downloads medRxiv surgery

Kashif Ramooz, Eesha Yaqoob, Nadeem Akhtar, Fraz Mehmood, Saad Javed

Hydrocephalus is routinely treated by surgical procedures. Cerebrospinal fluid shunt placement is a critical therapeutic intervention for hydrocephalus.CSF shunting has multiple complications among which infection is very common. The major cause of morbidity and mortality in patients with CSF shunts is theinfection of the central nervous system (CNS).It can lead to prolonged hospital stay, increase the number of operative procedures 03 times more than then none infected cases and has twice the fatality rate. Study of such type of complication will help the patients to improve their health and also improve our sterilization techniques and reduce burden of hospital and patients expenditures. The objective of the study was to determine the frequency of infection after cerebrospinal fluid shunting procedures.Case series study was used as study design.Study was conducted from 10-2010 to 10-06-2011.One hundred and forty four patients with both genders of all age groups undergoing cerebrospinal fluid shunting, meeting inclusion and exclusion criteria, were selected for the present study after informed consent of patient or guardian and approval by the hospital ethical committee. Follow up was ensured by taking the telephonic contact and address of patient.Total no of patients were 144 among which, 89 were males and 55 were females. Age distribution was from 01 month to 75 years with the mean age of 15.280 and standard deviation was {+/-} 20.450. Post-operative infection was present in 20(13.9%) patients. Authors approvalAll the authors have seen the manuscript and approved it. Declaration of interestNone Conflict/Competing of InterestNone. Disclosure of FundingNone. Ethical ApprovalAttached

71: Use of the Spatial Access Ratio to Measure Geospatial Access to Emergency Surgical Services in California
more details view paper

Posted 29 May 2020

Use of the Spatial Access Ratio to Measure Geospatial Access to Emergency Surgical Services in California
19 downloads medRxiv surgery

Marta L. McCrum, Neng Wan, Steven Lizotte, Jiuying Han, Thomas Varghese, Raminder Nirula

Background: Emergency general surgery (EGS) diseases carry a substantial public health burden, accounting for over 3 million admissions annually. Due to their time-sensitive nature, ensuring adequate access to EGS services is critical for reducing patient morbidity and mortality. Travel-time alone, without consideration of resource supply and demand, may be insufficient to determine a regional health care system's ability to provide timely access to EGS care. Spatial Access Ratio (SPAR) incorporates travel-time, as well as hospital-specific resources and capacity, to determine healthcare accessibility which may be more appropriate for surgical specialties. We therefore compared SPAR to travel-time in their ability to differentiate spatial access to EGS care for vulnerable populations. Methods: We constructed a Geographic Information Science (GIS) platform using existing road networks, and mapped population location, race and socioeconomic characteristics, as well as all EGS-capable hospitals in California. We then compared the shortest travel time method to the gravity-based SPAR in their ability to identify disparities in spatial access for the population as a whole, and subsequently to describe socio-demographic disparities. Reduced spatial access was defined at >60 minutes travel time, or lowest three classes of SPAR. Results: 283 EGS-capable hospitals were mapped, 142 (50%) of which had advanced resources. Using shortest travel time, 36.98M people (94.8%) were within 20-minutes driving time to any EGS capable hospital, and 33.49M (85.9%) to an advanced-resourced center. Only 166, 950 (0.4%) experienced prolonged (>60 minutes) travel time to any EGS-capable hospital, which increased to 1.05M (2.7%) for advanced-resources. Using SPAR, 11.5M (29.5%) of people had reduced spatial access to any EGS hospital, which increased to 13.9M (35.7%) when evaluating advanced-resource hospitals. The greatest disparities in spatial access to care were found for rural residents and Native Americans for both overall and advanced EGS services. Conclusions: While travel time and SPAR showed similar overall patterns of spatial access to EGS-capable hospitals, SPAR showed greater differentiation of spatial access across the state. Nearly one-third of California residents have limited or poor access to EGS hospitals, with the greatest disparities noted for Native American and rural residents. These findings argue for the use of gravity-based models such as SPAR that incorporate measures of population demand and hospital capacity when assessing spatial access to surgical services, and have implications for the allocation of healthcare resources to address disparities.

72: Titanium Fasteners In Endoscopic Mitral Valve Surgery
more details view paper

Posted 05 Jun 2020

Titanium Fasteners In Endoscopic Mitral Valve Surgery
19 downloads medRxiv surgery

Rafik Margaryan, Giacomo Bianchi, Tommaso Gasbarri, Giovanni Concistre, Marco Solinas

Objective We sought to review our experience of new titanium knot fastener devices. We hypothesized that it might reduce the cardiop-polmonary bypass time, aortic cross-clamping time and intervention time. Materials We reviewed our electronic records in order identify the patients who underwent mitral valve (MV) repair and replacement in totally endoscopic setup. Surgical approach was trough limited right periareolar or inframmamary thoracotomy with mainly femoro-femoral arterio-venous cannulation. A part of patients underwent interventions using fast knotting system (FK group,Cor-Knot Device, ISL Solutions Inc) and remaining patients served as control group (conventional hand knotting, HK). We identified the FK patients and performed propensity score matching to match 1:1 ratio from main cohort using FK versus HK. Results A total of 306 patients underwent mitral valve repair or replacement on via right thoracotomy, 265 (87%) patients underwent using FK, remaining. There were on average 2.6 minutes of CPB time reduction (p = 0.64), and 3.1 minutes of CXC time reduction (p = 0.47). However, when dividing into procedures based on complexity, there were on average 8.6 minutes of CPB time reduction (p = 0.18), and 6.9 minutes of CXC time reduction (p = 0.16) in simple cases; on average in complex cases 12 minutes of CPB time was augmented (p = 0.24), and 2.5 minutes of CXC time was augmented(p = 0.76). In propensity matched population the effect of CPB and CXC reduction was consistent and repeated and there were on average 0.5 minutes of CPB time reduction (p = 0.12), and 3.6 minutes of CXC time augmentation (p = 0.05). However, when dividing into procedures based on complexity, there were on average 0.2 minutes of CPB time reduction (p = 0.16), and 2.7 minutes of CXC time augmentation (p = 0.06) in simple cases; on average 5 minutes of CPB time augmentation (p = 0.34), and 14.2 minutes of CXC time augmentation (p = 0.58) in complex cases. Conclusions Titanium fasteners are useful tool to have in minimally invasive approaches, especially in complex cases and redo interventions. Titanium are comfortable and fast in many cases then conventional knot tying, but it is also expensive the traditional knotting. The titanium fasteners do not offer significant time reduction. In matched group the pattern of time saving were identical to main cohort.

73: Determinants of Cerebrovascular Reserve in Patients with Significant Carotid Stenosis
more details view paper

Posted 16 Nov 2020

Determinants of Cerebrovascular Reserve in Patients with Significant Carotid Stenosis
19 downloads medRxiv surgery

Joseph P Archie

IntroductionIn patients with 70% to 99% diameter carotid artery stenosis cerebral blood flow reserve may be protective of future ischemic cerebral events. Reserve cerebral blood flow is created by brain auto-regulation. Both cerebral blood flow reserve and cerebrovascular reactivity can be measured non-invasively. However, the factors and variables that determine the availability and magnitude and of reserve blood flow remain poorly understood. The availability of reserve cerebral blood flow is a predictor of stroke risk. The aim of this study is to employ a hemodynamic model to predict the variables and functional relationships that determine cerebral blood flow reserve in patients with significant carotid stenosis. MethodsA basic one-dimensional, three-unit (carotid, collateral and brain) energy conservation fluid mechanics blood flow model is employed. It has two distinct but adjacent blood flow components with normal cerebral blood flow at the interface. In the brain auto-regulated blood flow component cerebral blood flow is maintained normal by reserve flow. In the brain pressure dependent blood flow component cerebral blood flow is below normal because cerebral perfusion pressure is below the lower threshold value for auto-regulation. Patient specific values of collateral vascular resistance are determined from a model solution using clinically measured systemic and carotid arterial stump pressures. Collateral vascular resistance curves illustrate the model solutions for reserve and actual cerebral blood flow as a function of percent diameter carotid artery stenosis and mean systemic arterial pressure. The threshold cerebral perfusion pressure value for auto-regulation is assumed to be 50 mmHg. Normal auto-regulated regional cerebral blood flow is assumed to be 50 ml/min/100g. Cerebral blood flow and reserve blood flow solutions are given for systemic arterial pressures of 80, 90, 100, 110 and 120 mmHg and for three patient specific collateral vascular resistance values, Rw = 1.0 (mean patient value), Rw = 0.5 (lower 1 SD) and Rd = 3.0 (upper 1 SD). ResultsReserve cerebral blood flow is only available when a patients cerebral perfusion pressure is in the normal auto-regulatory range. Both actual and reserve cerebral blood flows are primarily from the carotid circulation when carotid stenosis is less than 60% diameter. Between 60% and 75% stenosis the remaining carotid blood flow reserve is utilized and at higher degrees of stenosis all reserve flow is from the collateral circulation. The primary independent variables that determine actual and reserve cerebral blood flow are mean systemic arterial pressure, degree of carotid stenosis and patient specific collateral vascular resistance. Approximate 16% of patients have collateral vascular resistance greater than 5.0 and are predicted to be at high risk of cerebral ischemia or infarction with progression to severe carotid stenosis or occlusion. The approximate 50% of patients with a collateral vascular resistance less than 1.0 are predicted to have adequate cerebral blood flow with progression to carotid occlusion, and most maintain some reserve. Clinically measured values of cerebral blood flow reserve or cerebrovascular reactivity are predicted to be unreliable without consideration of systemic arterial pressure and degree of carotid stenosis. Reserve cerebral blood flow values measured in patients with only moderate 60% to 70% carotid stenosis are in general too high and variable to be of clinical value, but are most reliable when measured near 80% diameter stenosis and considered as percent of the maximum reserve blood flow. Patient specific measured reserve blood flow values can be inserted into the model to calculate the collateral vascular resistance. ConclusionsPredicting cerebral blood flow reserve in patients with significant carotid stenosis is complex and multifactorial. A simple cerebrovascular model predicts that patient specific collateral vascular resistance is an excellent predictor of reserve cerebral blood flow in patients with significant carotid stenosis. Cerebral blood flow reserve measurements are of limited value without accounting for systemic pressure and actual percent carotid stenosis. Asymptomatic patients with severe carotid artery stenosis and a collateral vascular resistance greater than 1.0 are at increased risk of cerebral ischemia and may benefit from carotid endarterectomy.

74: The Role of Social Media in Disseminating Plastic Surgery Research: The Relationship between Citations, Altmetrics and Article Characteristics
more details view paper

Posted 01 Sep 2020

The Role of Social Media in Disseminating Plastic Surgery Research: The Relationship between Citations, Altmetrics and Article Characteristics
18 downloads medRxiv surgery

Michael C Grant, Ryckie G Wade, Kai R Scott-Bridge

Background: Social media (SoMe) enables publishers and authors to disseminate content immediately and directly to interested end-users, on a global scale. Alternative metrics (altmetrics) are non-traditional bibliometrics which describe the exposure and impact of an article on freely available platforms such as Twitter, Facebook, Wikipedia and the news. Altmetrics are strongly associated with ultimate citation counts in various medical disciplines, except plastic surgery which represents the rational for this study. Methods: Altmetric explorer was used to extract altmetrics and citation rates for articles published during 2018 in Plastic and Reconstructive Surgery (PRS), the Journal of Plastic, Reconstructive and Aesthetic Surgery, the Annals of Plastics Surgery and Plastic Surgery (also known as Chirurgie Plastique). Multivariable negative binomial regression was used to estimate the relationship between citations and predictors (presented as the incidence rate ratio, IRR with 95% confidence interval, CI). Results: Overall, 1215 plastic surgery articles were captured which were cited 3269 times. There was a strong and independent association between the number of mentions in SoMe and the number of times an article was cited (adjusted IRR 1.01 [95% CI 1.01, 1.1]), whereby each mention in SoMe (e.g. Tweets or Facebook posts) translated to one additional citation. Evidence synthesis articles (e.g. systematic reviews) were cited twice as often as other articles and again, the use of SoMe to advertise these outputs was independently associated with more citations (IRR 2.0 [95% CI 1.3, 3.2]). Conclusions: Dissemination of plastic surgery research through social media channels increases an articles impact as measured by citations.

75: A prospective observational cohort study considering the feasibility and tolerability of high intensity interval training as a novel treatment therapy for patients with intermittent claudication.
more details view paper

Posted 06 Apr 2020

A prospective observational cohort study considering the feasibility and tolerability of high intensity interval training as a novel treatment therapy for patients with intermittent claudication.
18 downloads medRxiv surgery

Sean Pymer, Said Ibeggazene, Joanne Palmer, George E. Smith, Amy E. Harwood, Sean Carroll, Lee Ingle, Ian C. Chetter

BackgroundUptake and completion rates for supervised exercise programmes (SEP) for patients with intermittent claudication (IC) are low. Current exercise prescription is a one size fits all approach, based on claudication pain thresholds, potentially limiting individual benefits. High-intensity interval training (HIIT) has the potential to overcome these barriers as it is a more time-efficient, objectively prescribed exercise programme. This study aimed to assess a novel HIIT programme for patients with IC in terms of safety, feasibility, tolerability and indicators of efficacy. Design/MethodsPatients referred to a usual-care SEP were invited to undertake an alternative HIIT programme. All recruited patients performed a baseline cardiopulmonary exercise test (CPET), to inform their exercise prescription. HIIT involved ten, one-minute high-intensity intervals on a stationary cycle ergometer interspersed with one-minute recovery intervals, performed three times per week for six-weeks. Outcomes included safety, feasibility, tolerability, walking distance and quality of life (QoL). Results144 patients with IC were referred, 95 met initial eligibility criteria (66%) and 30 (32%) were recruited for HIIT, of which 15 (50%) completed. Of the recruited patients, 90% were on optimal medical therapy and 40% had concomitant cardiac, cerebrovascular and/or respiratory disease. One serious adverse event was recorded and patients who completed the programme attended 100% of the sessions. Improvements in walking distances and quality of life were observed. Following recruitment of the first 20 patients, the inclusion criteria was refined on the basis of CPET, leading to improved completion rates. ConclusionThe study provides preliminary findings indicating that patients with IC can complete a short-term HIIT programme. HIIT also appears safe, well-tolerated and although not formally powered, walking distances and QoL appear to improve following HIIT. Further research to evaluate the role of HIIT in patients with IC seems warranted.

76: Fully Automated Delineation of the Optic Radiation for Surgical Planning using Clinically Accessible Sequences
more details view paper

Posted 18 Jul 2020

Fully Automated Delineation of the Optic Radiation for Surgical Planning using Clinically Accessible Sequences
17 downloads medRxiv surgery

Lee B. Reid, Eloy Martínez-Heras, Jose B Manjón, Rosalind L Jeffree, Hamish Alexander, Julie Trinder, Elisabeth Solana, Sara Llufriu, Stephen Rose, Marita Prior, Jurgen Fripp

Quadrantanopia caused by inadvertent severing of Meyer's Loop of the optic radiation is a well-recognised complication of temporal lobectomy for conditions such as epilepsy. Dissection studies indicate that the anterior extent of Meyer's Loop varies considerably between individuals. Quantifying this for individual patients is thus an important step to improve the safety profile of temporal lobectomies. Previous attempts to delineate Meyer's Loop using diffusion MRI tractography have had difficulty estimating its full anterior extent, required manual ROI placement, and/or relied on advanced diffusion sequences that cannot be acquired routinely in most clinics. Here we present CONSULT - a pipeline that can delineate the optic radiation from raw DICOM data in a completely automated way via a combination of robust preprocessing, segmentation, and alignment stages, plus simple improvements that bolster the efficiency and reliability of standard tractography. We tested CONSULT on 694 scans of predominantly healthy participants (538 unique brains), including both advanced acquisitions and simpler acquisitions that could be acquired in clinically acceptable timeframes. Delineations completed without error in 99.4% of the scans. The distance between Meyer's Loop and the temporal pole closely matched both averages and ranges reported in dissection studies for all tested sequences. Median scan-rescan error of this distance was 1mm. When tested on two participants with considerable pathology, delineations were successful and realistic. Through this, we demonstrate not only how to identify Meyer's Loop with clinically accessible sequences, but also that this can be achieved without fundamental changes to tractography algorithms or complex post-processing methods.

77: A prospective study to identify rates of SARS-CoV-2 virus in the peritoneum and lower genital tract of patients having surgery
more details view paper

Posted 01 Aug 2020

A prospective study to identify rates of SARS-CoV-2 virus in the peritoneum and lower genital tract of patients having surgery
16 downloads medRxiv surgery

Dominique Jones, David Faluyi, Sarah Hamilton, Nicholas Stylianides, Kenneth Ma, Sarah Duff, Nicholas Machin, Richard Edmondson

Introduction The risks to surgeons of carrying out aerosol generating procedures during the COVID pandemic are unknown. To start to define these risks, in a systematic manner, we investigated the presence of SARS-CoV-2 virus in the abdominal fluid and lower genital tract of patients undergoing surgery. Methods We carried out a prospective cross sectional observational study of 113 patients undergoing abdominal surgery or instrumentation of the lower genital tract. We took COVID swabs from the peritoneal cavity and from the vagina from all eligible patients. Results were stratified by pre operative COVID status. Results In patients who were presumed COVID negative at the time of surgery SARS-CoV-2 virus RNA was detected in 0/102 peritoneal samples and 0/98 vaginal samples. Peritoneal and vaginal swabs were also negative in one patient who had a positive nasopharyngeal swab immediately prior to surgery. Conclusions The presence of SARS-CoV-2 RNA in the abdominal fluid or lower genital tract of presumed negative patients is nil or extremely low. These data will inform surgeons of the risks of restarting laparoscopic surgery at a time when COVID19 is endemic in the population.

78: Seeing the light: Improving the usability of fluorescence-guided surgery by adding an optimized secondary light source
more details view paper

Posted 12 Mar 2020

Seeing the light: Improving the usability of fluorescence-guided surgery by adding an optimized secondary light source
16 downloads medRxiv surgery

Jonathan T. Elliott, Dennis J. Wirth, Scott C. Davis, Jonathan D. Olson, Nathan E. Simmons, Timothy C. Ryken, Keith D. Paulsen, David W. Roberts

BackgroundTumors that take up and metabolize 5-aminolevulinic acid (5-AlA) emit bright pink fluorescence when illuminated with blue light, aiding surgeons in identifying the margin of resection. The adoption of this method is hindered by the blue light illumination, which is too dim to safely operate under, and therefore, necessitates switching back and forth from white-light mode. This paper examines the addition of an optimized secondary illuminant adapter (SIA) to improve usability of blue-light mode without degrading tumor contrast. MethodsWe used color science methods to evaluate the color of the secondary illuminant and its impact on color rendering index (CRI) as well as the tumor-to-background color contrast (TBCC). A secondary illuminant adapter was built to provide 475-600 nm light the intensity of which can be controlled by the surgeon and was evaluated in two patients. ResultsSecondary illuminant color had opposing effects on color rendering index (CRI) and tumor to background color contrast (TBCC); providing surgeon control of intensity allows this trade-off to be balanced in real-time. Experience in two cases suggests additional visibility adds value. ConclusionThe addition of a secondary illuminant may mitigate surgeon complaints that the operative field is too dark under the blue light illumination required for 5-ALA fluorescence guidance by providing improved CRI without completely sacrificing TBCC.

79: Multifocal breast cancers are more prevalent in BRCA2 versus BRCA1 mutation carriers
more details view paper

Posted 13 Sep 2019

Multifocal breast cancers are more prevalent in BRCA2 versus BRCA1 mutation carriers
16 downloads medRxiv surgery

Alan D McCrorie, Susannah Ashfield, Aislinn Begley, Colin Mcilmunn, Patrick J. Morrison, Clinton Boyd, Bryony Eccles, Stephanie Greville-Heygate, Ellen R Copson, Ramsey I. Cutress, Diana M Eccles, Kienan I Savage, Stuart A McIntosh

Multifocal breast cancer is generally considered to be where two or more breast tumours are present within the same breast, but are clearly separated with no intervening in situ or invasive disease. It is seen in [~]10% of breast cancer cases. This study investigates multifocality prevalence in BRCA1/2 mutant patients via cross-sectional analysis. Data from 211 women with BRCA1/2 mutations (BRCA1 - 91), (BRCA2 - 120), with breast cancer were collected including age, tumour focality, size, type, grade, and receptor profile. The prevalence of multifocality within this group was 25%, but within subgroups, prevalence amongst BRCA2 carriers was more than double that of BRCA1 carriers (p=0.001). Women affected by multifocal tumours had proportionately higher oestrogen receptor positivity (p=0.001), lower triple negativity (p=0.004), and were more likely to be younger at diagnosis compared with those with unifocal tumours (p=0.039). Odds of a BRCA2 carrier developing multifocal cancer were almost four-fold higher than a BRCA1 carrier (OR: 3.71, CI: 1.77-7.78, p=0.001). BRCA2 carriers show much greater multifocality than those carrying BRCA1 - multifocal tumours are strongly associated with being both BRCA2 mutant and oestrogen receptor positive.

80: Enhanced recovery after surgery (ERAS) protocols is extermely beneficial in liver surgeries. A metaanalysis.
more details view paper

Posted 16 Apr 2020

Enhanced recovery after surgery (ERAS) protocols is extermely beneficial in liver surgeries. A metaanalysis.
16 downloads medRxiv surgery

BHAVIN VASAVADA

BACKGROUND: Enhanced recovery after surgery (ERAS) programs aim to improve postoperative outcomes.. This metaanalysis aims to evaluate the impact of ERAS programmes on outcomes following liver surgeries. METHODS: EMBASE, MEDLINE, PubMed and the Cochrane Database were searched for studies comparing outcomes in patients undergoing liver surgery utilizing ERAS principles with those patients receiving conventional care. The primary outcome was occurrence of 30 day morbidity and mortality. Secondary outcomes included length of stay , functional recovery ,readmission rates,time to pass flatus,blood loss and hospital costs. RESULTS: Ten articles were included in the metaanalysis. 30 days morbidity and mortality was significantly less in ERAS group.Hospital stay, time to pass flatus, time to complete recovery and hospital costs were also significantly reduced due to ERAS protocols. Blood loss and readmission rates were also significantly less in ERAS group. CONCLUSIONS: The adoption of ERAS protocols significantly reduced morbidity, mortality hospital stay, readmission rates, time to recovery, hospital costs, time to pass flatus, blood loss and readmission rates.

Previous page 1 2 3 4 5 6 Next page

PanLingua

News