163 results found
Leff DR, Lovegrove RE, Darzi LA, et al., 2010, Data collection, database development and quality control: Guidance for clinical research studies, Key Topics in Surgical Research and Methodology, Pages: 305-320, ISBN: 9783540719144
Data collection is fundamental to any clinical surgical research study. Without collecting reliable and accurate data, it is impossible to draw meaningful conclusions regarding the research question of interest. This chapter aims to provide an overview of how to plan generic data collection and data storage, protocols, training and analysis that promote accurate and reliable data collection. Additionally, the fundamentals of database models and storage are covered to aid the novice researcher. A wealth of more detailed database design information and administration is available elsewhere for those who wish to pursue more complex designs. Throughout this chapter, we illustrate principles explained using clinically relevant examples. © Springer-Verlag Berlin Heidelberg 2010.
Leff DR, Orihuela-Espina F, Athanasiou T, et al., 2010, Decoupling neurocognitive and technical performance in sleep deprived surgical residents through longitudinal analyses of cortical brain function: Advancing our understanding of compensation to acute fatigue, Annual Clinical Congress of American-College-of-Surgeons, Publisher: ELSEVIER SCIENCE INC, Pages: S118-S118, ISSN: 1072-7515
Orihuela-Espina F, Leff DR, James DRC, et al., 2010, Quality control and assurance in functional near infrared spectroscopy (fNIRS) experimentation, Physics in Medicine and Biology, Vol: 55, Pages: 3701-3724, ISSN: 1361-6560
Leff DR, James DRC, Orihuela-Espina F, et al., 2010, The frontal cortex is activated during learning of endoscopic procedures (Ohuchida et al., Surgical Endoscopy, January 2009), SURGICAL ENDOSCOPY AND OTHER INTERVENTIONAL TECHNIQUES, Vol: 24, Pages: 968-969, ISSN: 0930-2794
Najefi A, Leff DR, Nicolaou M, et al., 2010, Monitoring of Free Flaps Using Near-Infrared Spectroscopy: A Systematic Review of the Initial Trials, PLASTIC AND RECONSTRUCTIVE SURGERY, Vol: 125, Pages: 182E-184E, ISSN: 0032-1052
Unadkat SN, Leff DR, Teoh T-G, et al., 2010, Anorectal symptoms during pregnancy: how important is trimester?, INTERNATIONAL JOURNAL OF COLORECTAL DISEASE, Vol: 25, Pages: 375-379, ISSN: 0179-1958
Saso S, Vecht JA, Rao C, et al., 2010, Statin therapy may influence the incidence of postoperative atrial fibrillation: what is the evidence?, Texas Heart Institute Journal, Vol: 36, Pages: 521-529, ISSN: 1526-6702
Atrial fibrillation is the most common postoperative arrhythmia in patients who undergo cardiac surgery. We sought to determine whether the administration of statins reduces the incidence of postoperative atrial fibrillation in cardiac surgery patients. We performed a meta-analysis on all studies published between 2004 and 2008 that reported comparisons between statin treatment or nontreatment in these patients. Our primary focus was the incidence of postoperative atrial fibrillation. Random-effects modeling and sensitivity analysis were used to evaluate the consistency of the calculated treatment effect. Ten qualifying studies generated a total of 4,459 patients. The incidence of postoperative atrial fibrillation was 22.6% (622/2,758) in the statin-treated group and 29.8% (507/1,701) in the untreated group. Using the random-effects model, we calculated an odds ratio (OR) of 0.60 (95% confidence interval [CI], 0.48-0.76). When we considered only the 4 randomized studies (919 patients) in order to reduce the effects of heterogeneity, this significant reduction in the incidence of postoperative atrial fibrillation in the statin group was maintained (OR, 0.55; 95% CI, 0.41-0.73) with no heterogeneity (chi2 of heterogeneity, 2.96; P = 0.4). In studies wherein only coronary artery bypass grafting was performed, statin treatment decreased postoperative atrial fibrillation (OR, 0.64; 95% CI, 0.43-0.95). We conclude that statin administration results in a reduction in the incidence of atrial fibrillation in patients who undergo cardiac surgery. Further research into the underlying mechanism can elucidate possible relationships between the dosage and type of statin used.
James DRC, Orihuela-Espina F, Leff DR, et al., 2010, Cognitive Burden Estimation for Visuomotor Learning with fNIRS, 13th International Conference on Medical Image Computing and Computer-Assisted Intervention (MICCAI), Publisher: SPRINGER-VERLAG BERLIN, Pages: 319-326, ISSN: 0302-9743
Paggetti G, Menegaz G, Leff DR, et al., 2010, Exploring the link between depth perception, hand eye coordination and parietal lobe activation during robotic-assisted interventions, PERCEPTION, Vol: 39, Pages: 162-163, ISSN: 0301-0066
Paggetti G, Lin Y-C, Menegaz G, et al., 2010, DOES IT EXIST A LINK BETWEEN PERFORMANCE AND PARIETAL CORTEX ACTIVITY IN SURGICAL TASKS?, International Conference on Fuzzy Computation (ICFC 2010) and International Conference on Neural Computation (ICNC 2010), Publisher: SCITEPRESS, Pages: 381-384
Saso S, Vecht JA, Rao C, et al., 2009, Statin Therapy May Influence the Incidence of Postoperative Atrial Fibrillation What Is the Evidence?, TEXAS HEART INSTITUTE JOURNAL, Vol: 36, Pages: 521-529, ISSN: 0730-2347
Leff DR, Heath D, 2009, Surgery for obesity in adulthood., BMJ, Vol: 339
Leff DR, Hassell J, Sufi P, et al., 2009, Emergency and elective laparoscopic repair of spigelian hernias: two case reports and a review of the literature, Surgical Laparoscopy, Endoscopy & Percutaneous Techniques, Vol: 19, Pages: e152-e155, ISSN: 1530-4515
Diagnosing spigelian hernias through physical examinationcan be particularly challenging. Increasingly, laparoscopy isbeing used to both confirm the diagnosis and carry out therapeuticrepair. Here, we describe 2 cases of successful laparoscopic repairof spigelian hernias using an Endocatch assisted sutured technique.A review of the literature describing the role of laparoscopy in themanagement of spigelian hernia is also provided.
Patten DK, Layfield D, Arya S, et al., 2009, Single Best Answers in Surgery (SBA), Publisher: Hodder and Arnold, ISBN: 978-0340972359
Single Best Answers in Surgery offers a new approach to revising for surgical finals; by not only indicating the correct answer to each question, but explaining the full rationale used for finding the answer in each case. This means the book is invaluable not only for self-testing before an exam, but will have long-term value throughout a student's surgical studies, through to finals exams and beyond. The questions are arranged into topic areas, followed by a practice exam for true self-assessment.
Warren OJ, Leff DR, Athanasiou T, et al., 2009, The Neurocognitive Enhancement of Surgeons: An Ethical Perspective, JOURNAL OF SURGICAL RESEARCH, Vol: 152, Pages: 167-172, ISSN: 0022-4804
Leff DR, Orihuela-Espina F, Atallah L, et al., 2008, Functional prefrontal reorganization accompanies learning-associated refinements in surgery: A manifold embedding approach, 10th International Conference on Medical Image Computing and Computer-Assisted Intervention (MICCAI 2007), Publisher: TAYLOR & FRANCIS LTD, Pages: 325-339, ISSN: 1092-9088
Leff DR, Orihuela-Espina F, Atallah L, et al., 2008, Functional prefrontal reorganization accompanies learning-associated refinements in surgery: a manifold embedding approach., Comput Aided Surg, Vol: 13, Pages: 325-339
The prefrontal cortex (PFC) is known to be vital for acquisition of visuomotor skills, but its role in the attainment of complex technical skills which comprise both perceptual and motor components, such as those associated with surgery, remains poorly understood. We hypothesized that the prefrontal response to a surgical knot-tying task would be highly dependent on technical expertise, and that activation would wane in the context of learning success following extended practice. The present series of experiments investigated this issue, using functional Near Infrared Spectroscopy (fNIRS) and dexterity analysis to compare the PFC responses and technical skill of expert and novice surgeons performing a surgical knot-tying task in a block design experiment. Applying a data-embedding technique known as Isomap and Earth Mover's Distance (EMD) analysis, marked differences in cortical hemodynamic responses between expert and novice surgeons have been found. To determine whether refinement in technical skill was associated with reduced PFC demands, a second experiment assessed the impact of pre- and post-training on the PFC responses in novices. Significant improvements (p < 0.01) were observed in all performance parameters following training. Smaller EMD distances were observed between expert surgeons and novices following training, suggesting an evolving pattern of cortical responses. A random effect model demonstrated a statistically significant decrease in relative changes of total hemoglobin (Delta HbT) [coefficient = -3.825, standard error (s.e.) = 0.8353, z = -4.58, p < 0.001] and oxygenated hemoglobin (Delta HbO(2)) [coefficient = -4.6815, s.e = 0.6781, z = -6.90, p < 0.001] and a significant increase in deoxygenated hemoglobin (Delta HHb) [coefficient = 0.8192, s.e = 0.3034, z = 2.66, p < 0.01] across training. The results indicate that learning-related refinements in technical performance are mediated by temporal reductions in prefrontal activation.
Leff D, Leong J, Orihuela-Espina F, et al., 2008, Variations in prefrontal activation support technical performance improvements in surgical novices, Annual Meeting of the Society-of-Academic-and-Research-Surgery, Publisher: WILEY-BLACKWELL, Pages: 936-936, ISSN: 0007-1323
Leong JJH, Leff DR, Das A, et al., 2008, Validation of orthopaedic bench models for trauma surgery., J Bone Joint Surg Br, Vol: 90, Pages: 958-965
The aim of this study was to validate the use of three models of fracture fixation in the assessment of technical skills. We recruited 21 subjects (six experts, seven intermediates, and eight novices) to perform three procedures: application of a dynamic compression plate on a cadaver porcine model, insertion of an unreamed tibial intramedullary nail, and application of a forearm external fixator, both on synthetic bone models. The primary outcome measures were the Objective Structural Assessment of technical skills global rating scale on video recordings of the procedures which were scored by two independent expert observers, and the hand movements of the surgeons which were analysed using the Imperial College Surgical Assessment Device. The video scores were significantly different for the three groups in all three procedures (p < 0.05), with excellent inter-rater reliability (alpha = 0.88). The novice and intermediate groups specifically were significantly different in their performance with dynamic compression plate and intramedullary nails (p < 0.05). Movement analysis distinguished between the three groups in the dynamic compression plate model, but a ceiling effect was demonstrated in the intramedullary nail and external fixator procedures, where intermediates and experts performed to comparable standards (p > 0.6). A total of 85% (18 of 21) of the subjects found the dynamic compression model and 57% (12 of 21) found all the models acceptable tools of assessment. This study has validated a low-cost, high-fidelity porcine dynamic compression plate model using video rating scores for skills assessment and movement analysis. It has also demonstrated that Synbone models for the application of and intramedullary nail and an external fixator are less sensitive and should be improved for further assessment of surgical skills in trauma. The availability of valid objective tools of assessment of surgical skills allows further studies into improving methods of
Leff DR, Leong JJH, Warren O, et al., 2008, Near-infrared spectroscopy: Potential clinical benefits in surgery, JOURNAL OF THE AMERICAN COLLEGE OF SURGEONS, Vol: 206, Pages: 761-762, ISSN: 1072-7515
Leff DR, Aggarwal R, Rana M, et al., 2008, Laparoscopic skills suffer on the first shift of sequential night shifts: Program directors beware and residents prepare, ANNALS OF SURGERY, Vol: 247, Pages: 530-539, ISSN: 0003-4932
Leff DR, Leong JJH, Aggarwal R, et al., 2008, Could variations-in technical skills acquisition in surgery be explained by differences in cortical plasticity?, ANNALS OF SURGERY, Vol: 247, Pages: 540-543, ISSN: 0003-4932
Leff DR, Warren OJ, Enfield LC, et al., 2008, Diffuse optical imaging of the healthy and diseased breast: A systematic review, BREAST CANCER RESEARCH AND TREATMENT, Vol: 108, Pages: 9-22, ISSN: 0167-6806
Warren OJ, Alcock EMH, Choong AMTL, et al., 2008, Recombinant activated factor VII: A solution to refractory haemorrhage in vascular surgery?, EUROPEAN JOURNAL OF VASCULAR AND ENDOVASCULAR SURGERY, Vol: 35, Pages: 145-152, ISSN: 1078-5884
Leff DR, Elwell CE, Orihuela-Espina F, et al., 2008, Changes in prefrontal cortical behaviour depend upon familiarity on a bimanual co-ordination task: An fNIRS study, NEUROIMAGE, Vol: 39, Pages: 805-813, ISSN: 1053-8119
Leff DR, Orihuela-Espina F, Leong J, et al., 2008, Modelling Dynamic Fronto-Parietal Behaviour During Minimally Invasive Surgery - A Markovian Trip Distribution Approach, 11th International Conference on Medical Image Computing and Computer-Assisted Intervention (MICCAI2008), Publisher: SPRINGER-VERLAG BERLIN, Pages: 595-602, ISSN: 0302-9743
Leff DR, Leong J, Yang G-Z, et al., 2008, Visuo-spatial ability and fMRI cortical activation insurgery residents, AMERICAN JOURNAL OF SURGERY, Vol: 195, Pages: 138-138, ISSN: 0002-9610
Leong JJH, Atallah L, Mylonas GP, et al., 2008, Investigation of partial directed coherence for hand-eye coordination in laparoscopic training, 4th International Workshop on Medical Imaging and Augmented Reality, Publisher: SPRINGER-VERLAG BERLIN, Pages: 270-+, ISSN: 0302-9743
Leff D, Aziz O, Darzi A, 2007, Trucks, planes, and scalpels - Is there an evidence-based approach to surgeons' working hours?, ARCHIVES OF SURGERY, Vol: 142, Pages: 817-820, ISSN: 0004-0010
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