Surgery (St Vincent's) - Research Publications
Now showing items 1-12 of 725
The introduction of a mandatory mask policy was associated with significantly reduced COVID-19 cases in a major metropolitan city
(PUBLIC LIBRARY SCIENCE, 2021-07-21)
BACKGROUND: Whilst evidence of use of face masks in reducing COVID-19 cases is increasing, the impact of mandatory use across a large population has been difficult to assess. Introduction of mandatory mask use on July 22, 2020 during a resurgence of COVID-19 in Melbourne, Australia created a situation that facilitated an assessment of the impact of the policy on the epidemic growth rate as its introduction occurred in the absence of other changes to restrictions. METHODS AND FINDINGS: Exponential epidemic growth or decay rates in daily COVID-19 diagnoses were estimated using a non-weighted linear regression of the natural logarithm of the daily cases against time, using a linear spline model with one knot (lspline package in R v 3.6.3). The model's two linear segments pivot around the hinge day, on which the mask policy began to take effect, 8 days following the introduction of the policy. We used two forms of data to assess change in mask usage: images of people wearing masks in public places obtained from a major media outlet and population-based survey data. Potential confounding factors (including daily COVID-19 tests, number of COVID-19 cases among population subsets affected differentially by the mask policy-e.g., healthcare workers) were examined for their impact on the results. Daily cases fitted an exponential growth in the first log-linear segment (k = +0.042, s.e. = 0.007), and fitted an exponential decay in the second (k = -0.023, s.e. = 0.017) log-linear segment. Over a range of reported serial intervals for SARS-CoV-2 infection, these growth rates correspond to a 22-33% reduction in an effective reproduction ratio before and after mandatory mask use. Analysis of images of people in public spaces showed mask usage rose from approximately 43% to 97%. Analysis of survey data found that on the third day before policy introduction, 44% of participants reported "often" or "always" wearing a mask; on the fourth day after, 100% reported "always" doing so. No potentially confounding factors were associated with the observed change in growth rates. CONCLUSIONS: The mandatory mask use policy substantially increased public use of masks and was associated with a significant decline in new COVID-19 cases after introduction of the policy. This study strongly supports the use of masks for controlling epidemics in the broader community.
Impaired vascular endothelial function as a perioperative risk predictor - a prospective observational trial
BACKGROUND: In the recent years, an increasing number of patients with multiple comorbidities (e.g. coronary artery disease, diabetes, hypertension) presents to the operating room. The clinical risk factors are accompanied by underlying vascular-endothelial dysfunction, which impairs microcirculation and may predispose to end-organ dysfunction and impaired postoperative outcome. Whether preoperative endothelial dysfunction identifies patients at risk of postoperative complications remains unclear. In this prospective observational study, we tested the hypothesis that impaired flow-mediated dilation (FMD), a non-invasive surrogate marker of endothelial function, correlates with Days at Home within 30 days after surgery (DAH30). DAH30 is a patient-centric metric that captures postoperative complications and importantly also hospital re-admissions. METHODS: Seventy-one patients scheduled for major abdominal surgery were enrolled. FMD was performed pre-operatively prior to major abdominal surgery and patients were dichotomised at a threshold value of 10%. FMD was then correlated with DAH30 (primary endpoint) and postoperative complications (secondary endpoints). RESULTS: DAH30 did not differ between patients with reduced FMD and normal FMD (14 (4) (median (IQR)) vs. 15 (8), P = 0.8). Similary, no differences between both groups were found for CCI (normal FMD: 21 (30) (median (IQR)), reduced FMD: 26 (38), P = 0.4) or frequency of major complications (normal FMD: 7 (19%) (n (%)), reduced FMD: 12 (35%), P = 0.12). The regression analyses revealed that FMD in combination with ASA status and surgery duration had no additional significant predictive effect for DAH30, CCI or Clavien-Dindo score. CONCLUSION: FMD does not add predictive value with regards to DAH30, CCI or Clavien-Dindo score within our study cohort of patients undergoing abdominal surgery. TRIAL REGISTRATION: The study was registered in the German Clinical Trials Register ( DRKS00005472 ), prospectively registered on 25/11/2013.
'Managing My Patellofemoral Pain': the creation of an education leaflet for patients.
STUDY DESIGN: Qualitative, including consultation with international experts and patients. PURPOSE: Develop a brief yet comprehensive evidence-based education leaflet to be used as an adjunct in the management of patellofemoral pain (PFP) through consultation with both experts (clinical academics) and individuals with PFP. BACKGROUND: Appropriate patient education is an essential component of effective PFP management. However, there are currently no published educational resources for clinicians and researchers treating individuals with PFP to help translate current evidence into clinical practice. METHODS: A preliminary education leaflet titled 'Managing My Patellofemoral Pain' was created using information from the 'Best Practice Guide to Conservative Management of Patellofemoral Pain' and educational content used in published research. Feedback was sought from 21 experts (clinical academics) for accuracy, adequacy and clarity of the information in the leaflet using a semistructured questionnaire, and a number of suggested modifications were made as a result. Further feedback was sought from 20 patients diagnosed with PFP regarding the clarity and adequacy of information contained in the leaflet, and to determine additional educational resource needs. RESULTS: The leaflet created is titled 'Managing My Patellofemoral Pain' and the main topics of the leaflet are 'What might cause my knee pain?' and 'Treatment options', which are divided into exercise and additional treatments. Patient feedback was positive, and included a number of considerations for further education resource development. CONCLUSIONS: The 'Managing My Patellofemoral Pain' education leaflet may provide a valuable resource for patients, clinicians and researchers to assist the provision of education and translation of the current evidence.
Life or limb: an international qualitative study on decision making in sarcoma surgery during the COVID-19 pandemic.
OBJECTIVES: The COVID-19 pandemic is unprecedented as a global crisis over the last century. How do specialist surgeons make decisions about patient care in these unprecedent times? DESIGN: Between April and May 2020, we conducted an international qualitative study. Sarcoma surgeons from diverse global settings participated in 60 min interviews exploring surgical decision making during COVID-19. Interview data were analysed using an inductive thematic analysis approach. SETTING: Participants represented public and private hospitals in 14 countries, in different phases of the first wave of the pandemic: Australia, Argentina, Canada, India, Italy, Japan, Nigeria, Singapore, Spain, South Africa, Switzerland, Turkey, UK and USA. PARTICIPANTS: From 22 invited sarcoma surgeons, 18 surgeons participated. Participants had an average of 19 years experience as a sarcoma surgeon. RESULTS: 17/18 participants described a decision they had made about patient care since the start of the pandemic that was unique to them, that is, without precedence. Common to 'unique' decisions about patient care was uncertainty about what was going on and what would happen in the future (theme 1: the context of uncertainty), the impact of the pandemic on resources or threat of the pandemic to overwhelm resources (theme 2: limited resources), perceived increased risk to self (theme 3: duty of care) and least-worst decision making, in which none of the options were perceived as ideal and participants settled on the least-worst option at that point in time (theme 4: least-worst decision making). CONCLUSIONS: In the context of rapidly changing standards of justice and beneficence in patient care, traditional decision-making frameworks may no longer apply. Based on the experiences of surgeons in this study, we describe a framework of least-worst decision making. This framework gives rise to actionable strategies that can support decision making in sarcoma and other specialised fields of surgery, both during the current crisis and beyond.
The MURAL collection of prostate cancer patient-derived xenografts enables discovery through preclinical models of uro-oncology
(NATURE PORTFOLIO, 2021-08-19)
Preclinical testing is a crucial step in evaluating cancer therapeutics. We aimed to establish a significant resource of patient-derived xenografts (PDXs) of prostate cancer for rapid and systematic evaluation of candidate therapies. The PDX collection comprises 59 tumors collected from 30 patients between 2012-2020, coinciding with availability of abiraterone and enzalutamide. The PDXs represent the clinico-pathological and genomic spectrum of prostate cancer, from treatment-naïve primary tumors to castration-resistant metastases. Inter- and intra-tumor heterogeneity in adenocarcinoma and neuroendocrine phenotypes is evident from bulk and single-cell RNA sequencing data. Organoids can be cultured from PDXs, providing further capabilities for preclinical studies. Using a 1 x 1 x 1 design, we rapidly identify tumors with exceptional responses to combination treatments. To govern the distribution of PDXs, we formed the Melbourne Urological Research Alliance (MURAL). This PDX collection is a substantial resource, expanding the capacity to test and prioritize effective treatments for prospective clinical trials in prostate cancer.
On the Efficiency of Haptic Based Object Identification: Determining Where to Grasp to Get the Most Distinguishing Information
(FRONTIERS MEDIA SA, 2021-07-29)
Haptic perception is one of the key modalities in obtaining physical information of objects and in object identification. Most existing literature focused on improving the accuracy of identification algorithms with less attention paid to the efficiency. This work aims to investigate the efficiency of haptic object identification to reduce the number of grasps required to correctly identify an object out of a given object set. Thus, in a case where multiple grasps are required to characterise an object, the proposed algorithm seeks to determine where the next grasp should be on the object to obtain the most amount of distinguishing information. As such, the paper proposes the construction of the object description that preserves the association of the spatial information and the haptic information on the object. A clustering technique is employed both to construct the description of the object in a data set and for the identification process. An information gain (IG) based method is then employed to determine which pose would yield the most distinguishing information among the remaining possible candidates in the object set to improve the efficiency of the identification process. This proposed algorithm is validated experimentally. A Reflex TakkTile robotic hand with integrated joint displacement and tactile sensors is used to perform both the data collection for the dataset and the object identification procedure. The proposed IG approach was found to require a significantly lower number of grasps to identify the objects compared to a baseline approach where the decision was made by random choice of grasps.
Treatment of tungiasis using a tea tree oil-based gel formulation: protocol for a randomised controlled proof-of-principle trial
(BMJ PUBLISHING GROUP, 2021-01-01)
INTRODUCTION: Tungiasis (sand flea disease or jigger infestation) is a neglected tropical disease caused by penetration of female sand fleas, Tunga penetrans, in the skin. The disease inflicts immense pain and suffering on millions of people, particularly children, in Latin America, the Caribbean and sub-Saharan Africa. Currently, there is no standard treatment for tungiasis, and a simple, safe and effective tungiasis treatment option is required. Tea tree oil (TTO) has long been used as a parasiticidal agent against ectoparasites such as headlice, mites and fleas with proven safety and efficacy data. However, current data are insufficient to warrant a recommendation for its use in tungiasis. This trial aims to generate these data by comparing the safety and efficacy of a 5% (v/w) TTO proprietary gel formulation with 0.05% (w/v) potassium permanganate (KMnO4) solution for tungiasis treatment. METHODS AND ANALYSIS: This trial is a randomised controlled trial (RCT) in primary schools (n=8) in South-Western Kenya. The study will include school children (n=88) aged 6-15 years with a confirmed diagnosis of tungiasis. The participants will be randomised in a 1:1 ratio to receive a 3-day two times a day treatment of either 5% TTO gel or 0.05% KMnO4 solution. Two viable embedded sandflea lesions per participant will be targeted and the viability of these lesions will be followed throughout the study using a digital handheld microscope. The primary outcome is the proportion of observed viable embedded sand fleas that have lost viability (non-viable lesions) by day 10 (9 days after first treatment). Secondary outcomes include improvement in acute tungiasis morbidities assessed using a validated severity score for tungiasis, safety assessed through adverse events and product acceptability assessed by interviewing the participants to rate the treatment in terms of effectiveness, side effects, convenience, suitability and overall satisfaction. ETHICS AND DISSEMINATION: The trial protocol has been reviewed and approved by the University of Canberra Human Research Ethics Committee (HREC-2019-2114). The findings of the study will be presented at scientific conferences and published in a peer-reviewed journal. TRIAL REGISTRATION NUMBERS: Australian New Zealand Clinical Trials Registry (ACTRN12619001610123); PACTR202003651095100 and U1111-1243-2294.
Perioperative management and anaesthetic considerations in pelvic exenterations using Delphi methodology: results from the PelvEx Collaborative
(OXFORD UNIV PRESS, 2021-01-01)
BACKGROUND: The multidisciplinary perioperative and anaesthetic management of patients undergoing pelvic exenteration is essential for good surgical outcomes. No clear guidelines have been established, and there is wide variation in clinical practice internationally. This consensus statement consolidates clinical experience and best practice collectively, and systematically addresses key domains in the perioperative and anaesthetic management. METHODS: The modified Delphi methodology was used to achieve consensus from the PelvEx Collaborative. The process included one round of online questionnaire involving controlled feedback and structured participant response, two rounds of editing, and one round of web-based voting. It was held from December 2019 to February 2020. Consensus was defined as more than 80 per cent agreement, whereas less than 80 per cent agreement indicated low consensus. RESULTS: The final consensus document contained 47 voted statements, across six key domains of perioperative and anaesthetic management in pelvic exenteration, comprising preoperative assessment and preparation, anaesthetic considerations, perioperative management, anticipating possible massive haemorrhage, stress response and postoperative critical care, and pain management. Consensus recommendations were developed, based on consensus agreement achieved on 34 statements. CONCLUSION: The perioperative and anaesthetic management of patients undergoing pelvic exenteration is best accomplished by a dedicated multidisciplinary team with relevant domain expertise in the setting of a specialized tertiary unit. This consensus statement has addressed key domains within the framework of current perioperative and anaesthetic management among patients undergoing pelvic exenteration, with an international perspective, to guide clinical practice, and has outlined areas for future clinical research.
Factors associated with antimicrobial choice for surgical prophylaxis in Australia.
(Oxford University Press (OUP), 2020-09)
Background: Cefazolin is the most commonly recommended antimicrobial for surgical antimicrobial prophylaxis (SAP). However, the Australian Surgical National Antimicrobial Prescribing Survey revealed a wide range of antimicrobials prescribed for SAP. Inappropriate use of broad-spectrum antimicrobials is associated with increased patient harm and is a posited driver for antimicrobial resistance. Objectives: To describe patient, hospital and surgical factors that are associated with appropriateness of the top five prescribed antimicrobials/antimicrobial classes for procedural SAP. Methods: All procedures audited from 18 April 2016 to 15 April 2019 in the Surgical National Antimicrobial Prescribing Survey were included in the analysis. Estimated marginal means analyses accounted for a range of variables and calculated a rate of adjusted appropriateness (AA). Subanalyses of the top five audited antimicrobials/antimicrobial classes identified associations between variables and appropriateness. Results: A total of 12 419 surgical episodes with 14 150 prescribed initial procedural doses were included for analysis. When procedural SAP was prescribed, appropriateness was low (57.7%). Allergy status, surgical procedure group and the presence of prosthetic material were positively associated with cefazolin and aminoglycoside appropriateness (P < 0.05). There were no significant positive associations with glycopeptides and third/fourth-generation cephalosporins. The use of broad-spectrum antimicrobials was the most common reason for inappropriate choice (67.9% of metronidazole to 83.3% of third/fourth-generation cephalosporin prescriptions). Conclusions: Various factors influence appropriateness of procedural SAP choice. Identification of these factors provides targets for antimicrobial stewardship interventions, e.g. procedures where surgeons are regularly prescribing broad-spectrum SAP. These can be tailored to address local hospital prescribing practices.
Quantifying the Effect of Location Matching on Accuracy of Multiparametric Magnetic Resonance Imaging Prior to Prostate Biopsy-A Multicentre Study
Background: Multiparametric magnetic resonance imaging (mpMRI) has shown promise to improve detection of prostate cancer over conventional methods. However, most studies do not describe whether the location of mpMRI lesions match that of cancer found at biopsy, which may lead to an overestimation of accuracy. Objective: To quantitate the effect of mapping locations of mpMRI lesions to locations of positive biopsy cores on the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of mpMRI. Design setting and participant: We retrospectively identified patients having mpMRI of the prostate preceding prostate biopsy at three centres from 2013 to 2016. Men with targetable lesions on imaging underwent directed biopsy in addition to systematic biopsy. We correlated locations of positive mpMRI lesions with those of positive biopsy cores, defining a match when both were in the same sector of the prostate. We defined positive mpMRI as Prostate Imaging Reporting and Data System (PI-RADS) score ≥4 and significant cancer at biopsy as grade group ≥2. Outcome measurements and statistical analysis: Sensitivity, specificity, PPV, and NPV were calculated with and without location matching. Results and limitations: Of 446 patients, 247 (55.4%) had positive mpMRI and 232 (52.0%) had significant cancer at biopsy. Sensitivity and NPV for detecting significant cancer with location matching (both 63.4%) were decreased compared with those without location matching (77.6% and 73.9%, respectively). Of the 85 significant cancers not detected by mpMRI, most were of grade group 2 (64.7%, 55/85). Conclusions: We report a 10-15% decrease in sensitivity and NPV when location matching was used to detect significant prostate cancer by mpMRI. False negative mpMRI remains an issue, highlighting the continued need for biopsy and for improving the standards around imaging quality and reporting. Patient summary: The true accuracy of multiparametric magnetic resonance imaging (mpMRI) must be determined to interpret results and better counsel patients. We mapped the location of positive mpMRI lesions to where cancer was found at biopsy and found, when compared with matching to cancer anywhere in the prostate, that the accuracy of mpMRI decreased by 10-15%.
Knowledge and attitudes of Australian dermatologists towards sentinel lymph node biopsy for melanoma: a mixed methods study.
BACKGROUND/OBJECTIVES: In melanoma management, sentinel lymph node biopsy (SLNB) is used to stage patients and to indicate prognosis. More recently, it has been used to select patients for adjuvant therapy. This study aimed to report knowledge of and attitudes towards SLNB for patients with melanoma among Australian dermatologists. METHODS: Mixed methods study using cross-sectional questionnaires (n = 88) and semi-structured interviews (n = 13), May-September 2019. RESULTS: Of the dermatologists surveyed, 56% thought SLNB had an important role in melanoma management, 26% were unsure and 18% thought SLNB unimportant. Of the 92% who would discuss SLNB with their patients, the main stated value of SLNB was for assessing eligibility for adjuvant therapies (79%); only 60% indicated SLNB was of value for providing prognostic information, and just over half (53%) thought it could improve staging. Interview data indicated that attitudes towards SLNB are shifting among dermatologists, driven by data from landmark clinical trials and the influence of professional networks. Accordingly, interviewees adopted one of three positions in relation to SLNB: (a) believed in utility of SLNB and adhered to the guidelines; (b) were unconvinced about utility of SLNB but adhered to the guidelines; and (c) were unconvinced about utility of SLNB and did not adhere to the guidelines. CONCLUSION: Although most of the dermatologists surveyed were familiar with and follow the SLNB recommendations, some disagreement with and distrust of the recommendations was evident. Greater acceptance of the SLNB recommendations appeared to be driven by the improved outcomes demonstrated in stage III patients receiving adjuvant systemic therapy.
Lymphoedema rates in pedicled anterolateral thigh flaps for coverage of irradiated groin defects.
BACKGROUND: Limb salvage surgery in conjunction with adjuvant radiotherapy is the preferred treatment for soft tissue sarcoma. This study aims to determine if ipsilateral pedicled anterolateral thigh (ALT) flap reconstruction of groin defects post soft tissue sarcoma resection results in acceptable rates of lymphoedema, while also providing good soft tissue cover and minimal donor site morbidity. METHODS: A retrospective chart audit was conducted with ethics approval, obtaining a case series of 16 patients operated on at a single institution by the senior surgeon. Patients who underwent ipsilateral pedicled ALT flap coverage of irradiated groin defects following soft tissue sarcoma resection were included. Comparative six-point limb circumference measurements were utilized to diagnose lymphoedema, with a difference of 10% when compared to the non-operative side being deemed significant. RESULTS: Lymphoedema was noted in three patients (18.8%) with an average follow-up period of 40.9 (range 8-59) months. CONCLUSION: Previously published lymphoedema rates in sarcoma limb salvage surgery of 15.5-30% are comparable to the rates obtained in this cohort. Lymphoedema rates do not appear to be higher in patients undergoing ipsilateral pedicled ALT flap reconstruction, thus making it a useful soft tissue coverage technique in this cohort.