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Ara Darzi

Publications and source records attributed to Ara Darzi.

At least 19 recordsLinked to original sources
PubMed2006

Minimally invasive conduit harvesting: a systematic review.

Minimally invasive conduit harvesting techniques for coronary artery bypass grafting have developed over the past decade, aiming to reduce the morbidity and recovery time associated with the procedure, whilst preserving the quality of the conduit. Two types of commonly harvested free conduits include the great saphenous vein and the radial artery. Although much research has focussed on comparing less invasive and conventional harvest techniques, there is at present no consensus on the areas where one technique is superior to the other. Aspects of conduits that deserve appreciation when comparing minimally invasive and open harvesting techniques include wound healing at the harvest site, the macroscopic, histological and functional quality of the conduit, but perhaps most importantly its long-term angiographic patency. This paper aims to review the literature comparing minimally invasive and conventional conduit harvesting techniques for coronary artery bypass grafting, with regard to the previously mentioned factors. A literature search of Medline, Ovid, Embase and Cochrane databases was used to identify comparative studies published between 1997 and 2005. Outcomes of interest included: wound infection, non-infective healing disturbances, post-operative pain, neurological disturbance, mobility, patient satisfaction, conduit quality (macroscopic, histological and functional) and long-term conduit patency. A scoring system was applied and used to grade the quality of the evidence, based on which a recommendation of it being 'good' (Grade A), 'fair' (Grade B), or 'insufficient' (Grade C) was made. Results showed that there was 'good' evidence to suggest that wound infection and non-infective complications are reduced with minimally invasive harvest as compared to conventional vein harvest. The evidence suggesting that post-operative pain and mobilisation is reduced after minimally invasive vein harvest and that once harvested, the conduits are macroscopically comparable to conventional ones, is only 'fair'. Finally, although initial reports are encouraging, there is at present insufficient evidence to comment on whether minimally invasive radial artery harvesting is better than that of conventional open surgery. Wounds from minimally invasively harvested venous conduits appear to be less prone to complications although more comparative evidence on conduit quality and long-term patency is eagerly awaited.

Coronary Artery Bypass↗
PubMed2006

Objective assessment of small bowel anastomosis skill in trainee general surgeons and urologists.

INTRODUCTION: The object of this study was to compare the technical ability of general surgery and urology trainees to perform a small bowel anastomosis using a life-like bench model. METHODS: Forty subjects were divided into two groups based on the stage of their training. Specialist registrars (SpRs) trained for 1 to 3 years were defined as junior SpRs, and those with 4 to 6 years of training were defined as senior SpRs. They were asked to perform a small bowel anastomosis on a standard latex model using the same equipment, suture material, and standardized instructions. Trainees were assessed by three trained observers based on a global rating scale. RESULTS: Interrater reliability was 0.83 for the general surgical group and 0.88 for the urology group. The median scores obtained by the junior SpRs were lower than those achieved by the senior SpRs, and general surgical trainees consistently performed better than their matched urology group. This difference reached statistical significance for the senior group. CONCLUSIONS: Global rating scores provide a reliable, valid method for assessing technical skills between specialties when performing a small bowel anastomosis. We provide reasons why general surgeons may be more proficient at this task than urologists. These findings have possible application to identifying trainees who need additional training and may also provide a mechanism to ensure competence in this task.

Adult↗
PubMed2006

Reduction in adhesive small-bowel obstruction by Seprafilm adhesion barrier after intestinal resection.

INTRODUCTION: Although Seprafilm has been demonstrated to reduce adhesion formation, it is not known whether its usage would translate into a reduction in adhesive small-bowel obstruction. METHODS: This was a prospective, randomized, multicenter, multinational, single-blind, controlled study. This report focuses on those patients who underwent intestinal resection (n = 1,701). Before closure of the abdomen, patients were randomized to receive Seprafilm or no treatment. Seprafilm was applied to adhesiogenic tissues throughout the abdomen. The incidence and type of bowel obstruction was compared between the two groups. Time to first adhesive small-bowel obstruction was compared during the course of the study by using survival analysis methods. The mean follow-up time for the occurrence of adhesive small-bowel obstruction was 3.5 years. RESULTS: There was no difference between the treatment and control group in overall rate of bowel obstruction. The incidence of adhesive small-bowel obstruction requiring reoperation was significantly lower for Seprafilm patients compared with no-treatment patients: 1.8 vs. 3.4 percent (P < 0.05). This finding represents an absolute reduction in adhesive small-bowel obstruction requiring reoperation of 1.6 percent and a relative reduction of 47 percent. In addition, a stepwise multivariate analysis indicated that the use of Seprafilm was the only predictive factor for reducing adhesive small-bowel obstruction requiring reoperation. In both groups, 50 percent of first adhesive small-bowel obstruction episodes occurred within 6 months after the initial surgery with nearly 30 percent occurring within the first 30 days. Additionally no first adhesive small-bowel obstruction events were reported in Years 4 and 5 of follow-up. CONCLUSIONS: The overall bowel obstruction rate was unchanged; however, adhesive small-bowel obstruction requiring reoperation was significantly reduced by the use of Seprafilm, which was the only factor that predicted this outcome.

Adolescent↗
PubMed2006

The effects of stress on surgical performance.

BACKGROUND: Although the general literature on stress and performance is extensive, little is known about specific effects of stress in surgical practice. This qualitative study explored key surgical stressors, their impact on performance, and coping strategies used by surgeons. METHODS: Individual in-depth semistructured interviews with surgeons were analyzed by 2 researchers independently. Key themes were discussed within the research team. RESULTS: Sixteen interviews were performed, including interviews with consultants (n = 9) and surgeons in training (n = 7). A wide range of intraoperative stressors was identified. Although stress had both positive and negative effects, undue levels of stress impaired judgment, decision making, and communication. Although junior surgeons showed uncertainty about their ability to cope, senior surgeons had developed sophisticated strategies for controlling each situation. CONCLUSIONS: Although stress poses significant risks, coping strategies are not taught explicitly during surgical training. This article presents a framework for categorizing surgical stress and suggests key elements for effective coping strategies.

Adaptation, Psychological↗
PubMed2006

A competency-based virtual reality training curriculum for the acquisition of laparoscopic psychomotor skill.

BACKGROUND: Studies have demonstrated the beneficial effect of training novice laparoscopic surgeons using virtual reality (VR) simulators, although there is still no consensus regarding an optimal VR training curriculum. This study aims to establish and validate a structured VR curriculum to provide an evidence-based approach for laparoscopic training programmes. METHODS: The minimally invasive VR simulator (MIST-VR) has 12 abstract laparoscopic tasks, each at 3 graduated levels of difficulty (easy, medium, and hard). Twenty medical students completed 2 sessions of all tasks at the easy level, 10 sessions at the medium level, and finally 5 sessions of the 2 most complex tasks at the hard level. At the medium level, subjects were randomized into 2 equal groups performing either all 12 tasks (group A) or the 2 most complex tasks (group B). Performance was measured by time taken, path length, and errors for each hand. The results were compared between groups, and to those of 10 experienced laparoscopic surgeons. RESULTS: Baseline performance of both groups was similar at the easy level. At the medium level, learning curves for all 3 parameters reached plateau at the second (group A, P < .05) and sixth (group B, P < .05) repetitions. Performance at the hard level was similar between the 2 groups, and all achieved the pre-set expert criteria. CONCLUSION: A graduated laparoscopic training curriculum enables trainees to familiarise, train and be assessed on laparoscopic VR simulators. This study can aid the incorporation of VR simulation into established surgical training programmes.

Adolescent↗
PubMed2006

Laparoscopic versus open appendectomy in children: a meta-analysis.

OBJECTIVE: This study aims to use meta-analysis to compare laparoscopic and open appendectomy in a pediatric population. SUMMARY BACKGROUND DATA: Meta-analysis is a statistical tool that can be used to evaluate the literature in both qualitative and quantitative ways, accounting for variations in characteristics that can influence overall estimate of outcomes of interest. Meta-analysis of laparoscopic versus open appendectomy in a pediatric population has not previously been performed. METHODS: Comparative studies published between 1992 and 2004 of laparoscopic versus open appendectomy in children were included. Endpoints were postoperative pyrexia, ileus, wound infection, intra-abdominal abscess formation, operative time, and postoperative hospital stay. RESULTS: Twenty-three studies including 6477 children (43% laparoscopic, 57% open) were included. Wound infection was significantly reduced with laparoscopic versus open appendectomy (1.5% versus 5%; odds ratio [OR] = 0.45, 95% confidence interval [CI], 0.27-0.75), as was ileus (1.3% versus 2.8%; OR = 0.5, 95% CI, 0.29-0.86). Intra-abdominal abscess formation was more common following laparoscopic surgery, although this was not statistically significant. Subgroup analysis of randomized trials did not reveal significant difference between the 2 techniques in any of the 4 complications. Operative time was not significantly longer in the laparoscopic group, and postoperative stay was significantly shorter (weighted mean difference, -0.48; 95% CI, -0.65 to -0.31). Sensitivity analysis identified lowest heterogeneity when only randomized studies were considered, followed by prospective, recent, and finally large studies. CONCLUSIONS: The results of this meta-analysis suggest that laparoscopic appendectomy in children reduces complications. However, we also see the need for further high-quality randomized trials comparing the 2 techniques, matched not only for age and sex but also for obesity and severity of appendicitis.

Appendectomy↗
PubMed2006

The use of a GripForce system to map force distribution patterns of laparoscopic instruments.

While it is acknowledged that the forces required to manipulate laparoscopic instruments can be significant and are important in terms of potential discomfort after prolonged use, no systematic study has been conducted. In this paper we present a GripForce system that allows for the mapping of force distribution patterns of laparoscopic instruments. Initial results showed significant differences in force distribution between various instrument handles, thus demonstrating the viability of the system and proposed methodology. Analysis of force distribution patterns of laparoscopic instruments can help towards improving instrument design, better understanding the relationship between force applied and performance, as well as provide useful feedback to trainees and surgeons.

Computer Simulation↗
PubMed2005

Does Doppler echography have a diagnostic role in patency assessment of internal thoracic artery grafts?

The amount of literature published over the past decade comparing coronary angiography with transthoracic Doppler echocardiography assessment of internal thoracic artery graft patency after CABG is substantial. There has been no review of the available literature, and conflicting reports of diagnostic accuracy have prevented routine use of transthoracic Doppler in graft patency assessment. Thus, this article reviews the available literature on diagnostic accuracy of transthoracic Doppler echocardiography of coronary bypass grafts. Relevant studies were identified and meta-analysis of diagnostic accuracy was performed. Study quality was assessed. Quantitative data synthesis included calculation of sensitivity, specificity, summary receiver operating characteristic curve analysis, pooled analysis and meta-regression of accuracy against study quality, publication date, angina, probe frequency and diagnostic criteria. Twenty studies of 929 patients produced 26 results included for analysis. Grafts were not visualized in 93 (10%) patients. Pooled sensitivity (85%) and specificity (94%) and diagnostic odds ratio (100.7) were high. SROC analysis showed an area under the curve of 0.96. Heterogeneity of results was due to variations in diagnostic criteria and study size. Subgroup analysis showed best performance in patients with postoperative angina (p = 0.014). Study quality did not affect results. Diastolic fraction less than 0.5 (sensitivity 89%, specificity 94%) was shown to be the best criterion for prediction of stenosis. Performance was lower using peak diastolic to systolic velocity ratio less than 1 (sensitivity 85%, specificity 86%). Transthoracic Doppler echography is effective in first-line assessment of left internal thoracic artery graft patency. It shows high specificity, prevents invasive investigations and improves in patients with postoperative angina. TDE is best used in combination with other non-invasive tests due to its inability to visualize the graft. The potential for use in postoperative coronary bypass patients is high.

Adult↗
PubMed2005

Handheld computers and the 21st century surgical team: a pilot study.

BACKGROUND: The commercial development and expansion of mobile phone networks has led to the creation of devices combining mobile phones and personal digital assistants, which could prove invaluable in a clinical setting. This pilot study aimed to look at how one such device compared with the current pager system in facilitating inter-professional communication in a hospital clinical team. METHODS: The study looked at a heterogeneous team of doctors (n = 9) working in a busy surgical setting at St. Mary's Hospital in London and compared the use of a personal digital assistant with mobile phone and web-browsing facilities to the existing pager system. The primary feature of this device being compared to the conventional pager was its use as a mobile phone, but other features evaluated included the ability to access the internet, and reference data on the device. A crossover study was carried out for 6 weeks in 2004, with the team having access to the personal digital assistant every alternate week. The primary outcome measure for assessing efficiency of communication was the length of time it took for clinicians to respond to a call. We also sought to assess the ease of adoption of new technology by evaluating the perceptions of the team (n = 9) to personal digital assistants, by administering a questionnaire. RESULTS: Doctors equipped with a personal digital assistant rather than a pager, responded more quickly to a call and had a lower of failure to respond rate (RR: 0.44; 95%CI 0.20-0.93). Clinicians also found this technology easy to adopt as seen by a significant reduction in perceptions of nervousness to the technology over the six-week study period (mean (SD) week 1: 4.10 (SD 1.69) vs. mean (SD) week 6: 2.20 (1.99); p = 0.04). CONCLUSION: The results of this pilot study show the possible effects of replacing the current hospital pager with a newer, more technologically advanced device, and suggest that a combined personal digital assistant and mobile phone device may improve communication between doctors. In the light of these encouraging preliminary findings, we propose a large-scale clinical trial of the use of these devices in facilitating inter-professional communication in a hospital setting.

Attitude of Health Personnel↗
PubMed2005

Objective assessment of technical skills in cardiac surgery.

OBJECTIVE: Reduced training time combined with no rigorous assessment for technical skills makes it difficult for trainees to monitor their competence. We have developed an objective bench-top assessment of technical skills at a level commensurate with a junior registrar in cardiac surgery. METHODS: Forty cardiothoracic surgeons were recruited for the study, consisting of 12 junior trainees (year 1-3), 15 senior trainees (year 4-6) and 13 consultants. The assessment consisted of four key tasks on standardised bench-top models: aortic root cannulation, vein-graft to aorta anastomosis, vein-graft to Left Anterior Descending (LAD) anastomosis and femoral triangle dissection. An expert surgeon was present at each station to provide passive assistance and rate performance on a validated global rating scale giving rise to a total possible score of 40. Three expert surgeons repeated the ratings retrospectively, using blinded video recordings. Data analysis employed non-parametric tests. RESULTS: Both live and video scores differentiated significantly between performances of all groups of surgeons for all four stations (P < 0.01) (median live and video score for LAD; Junior 19,17; Senior 29,22; Consultant 36,28). Correlations between live and blinded rating were high (r = 0.67-0.84; P < 0.001) as was inter-rater reliability between the three expert video raters (alpha = 0.81). CONCLUSIONS: The use of bench-top tasks to differentiate between cardiac surgeons of differing technical abilities has been validated for the first time. Furthermore, it is unnecessary to perform post-hoc video rating to obtain objective data. These measures can provide formative feedback for surgeons-in-training and lead to the development of a competency-based technical skills curriculum.

Cardiac Surgical Procedures↗
PubMed2005

Synchronized video and motion analysis for the assessment of procedures in the operating theater.

HYPOTHESIS: Objective assessment of surgical skill has recently been shown to be possible through the use of dexterity-based and video analysis systems. The aim of this study was to synchronize these 2 modalities to produce a comprehensive surgical assessment tool. DESIGN: The Imperial College Surgical Assessment Device is a dexterity-based motion analysis device that has been developed in the Department of Surgical Oncology and Technology by the Surgical Computing and Imaging Research Group. Further advances to this system have been made to enable synchronized acquisition of hand kinematics and video from real procedures, and their concurrent analysis. To test the feasibility of the system, 10 laparoscopic cholecystectomies performed by 5 different surgeons on consenting patients were recorded. Analysis focused on the entire procedure and also on specific parts of the operation such as the clipping and cutting of the cystic duct and artery. RESULTS: Dexterity analysis was performed using the objective measures of time, path length, number of movements, velocities, and trajectories. Comparative analysis of a surgeon's dexterity was carried out on the whole procedure and by using the synchronized zoom facility in the software. Kinematic signals revealed rapid changes in velocity caused by alternating between different instruments or occurring after complications such as bleeding. CONCLUSION: This new motion analysis system has been shown to be an effective tool for the comprehensive assessment of operative procedures.

Cholecystectomy, Laparoscopic↗
PubMed2005

A comparison of open vs. laparoscopic abdominal rectopexy for full-thickness rectal prolapse: a meta-analysis.

PURPOSE: Using meta-analytical techniques, this study was designed to compare open and laparoscopic abdominal procedures used to treat full-thickness rectal prolapse in adults. METHODS: Comparative studies published between 1995 and 2003, cited in the literature of open abdominal rectopexy vs. laparoscopic abdominal rectopexy, were used. The primary end points were recurrence and morbidity, and the secondary end points assessed were operative time and length of hospital stay. A random effect model was used to aggregate the studies reporting these outcomes, and heterogeneity was assessed. RESULTS: Six studies, consisting of a total of 195 patients (98 open and 97 laparoscopic) were included. Analysis of the data suggested that there is no significant difference in recurrence and morbidity between laparoscopic abdominal rectopexy and open abdominal rectopexy. Length of stay was significantly reduced in the laparoscopic group by 3.5 days (95 percent confidence interval, 3.1-4; P < 0.01), whereas the operative time was significantly longer in this group, by approximately 60 minutes (60.38 minutes; 95 percent confidence interval, 49-71.8). CONCLUSIONS: Laparoscopic abdominal rectopexy is a safe and feasible procedure, which may compare equally with the open technique with regards to recurrence and morbidity and favorably with length of stay. However large-scale randomized trials, with comparative, sound methodology are still needed to ascertain detailed outcome measures accurately.

Adult↗
PubMed2005

Surgical skill is predicted by the ability to detect errors.

BACKGROUND: Objective analysis methods of surgical performance are now available so comparison between surgeons is available. One such method is by direct observation using the Objective Structured Assessment of Technical Skills (OSATS), but this is a time-consuming process; therefore, a simple screening tool for the ability to detect errors (previously validated) was analyzed and considered as a predictor of qualitative performance. METHODS: Thirty-eight volunteer surgeons were recruited to the skills laboratory to undertake 3 exercises. Two were bench-top surgical tasks that were scored using the global rating of the OSATS technique. The third task was the ability to detect simple errors in 22 synthetic models of common surgical procedures, some of which contained purposefully made errors. P<.05 was deemed to be statistically significant. RESULTS: The scores (interquartile ranges in parentheses) for the 3 sections were excision of sebaceous cyst=21 (19,24), closure of small bowel enterotomy=23 (21,27), and identification of errors=31 (27,34). Three scorers blinded to the operative models exhibited an interobserver reliability of .9 and .91 for the video tasks, respectively. Spearman's rank correlations between the error examination and performance on the 2 tasks were both statistically significant at .69 (cystectomy) and .54 (enterotomy). CONCLUSIONS: The ability to detect simple surgical errors is a predictor of technical skill and performance of bench tasks. What must be answered is whether the use of such models and principles can shorten the qualitative surgical learning curve.

Clinical Competence↗
PubMed2005

The reliability of multiple objective measures of surgery and the role of human performance.

BACKGROUND: There is a need for reliable and valid objective methods of technical skills in surgery. Six-bench surgical top stations have been combined to assess basic surgical trainees (BSTs) objectively. The current study examines its reliability and validity across repeat sittings. METHODS: Eleven surgical trainees (6 senior BSTs and 5 higher surgical trainees [HSTs]) undertook 5 sittings of the 6-station assessment designed to be completed within 90 minutes. The 6 stations consisted of knot tying, suturing, closure of enterotomy, excision of sebaceous cyst, laparoscopic task, and instrument examination. Methods of analysis employed were motion analysis, observation with criteria, and inbuilt simulation metrics. RESULTS: On analysis 3 knot tying and suturing stations exhibited significant differences in either time or movement; any difference was over by the second run. The intertest reliabilities were .66, .74, .55, .51, and .65 for the 5 runs. The intratest reliability across repeated sittings varied from .56 to .96. The inter-rater reliability for video assessment varied from .77 to .94. CONCLUSION: The assessment is reliable and valid across repeated sittings. Its use in assessment of basic technical skills needs to be encouraged.

Clinical Competence↗
PubMed2005

Assessment of psychomotor skills acquisition during laparoscopic cholecystectomy courses.

BACKGROUND: Standardized short courses in laparoscopic cholecystectomy aim to teach laparoscopic skills to surgical trainees, although end-of-course assessments of performance remain subjective. The current study aims to objectively assess psychomotor skills acquisition of trainees attending laparoscopic cholecystectomy courses. METHODS: Thirty-seven junior surgical trainees had their laparoscopic skills assessed before and after attending 1 of 3 separate 2-day courses (A, B, and C), all with identical format. Assessments were comprised of a standardized simulated laparoscopic task, with performance measured using a valid electromagnetic hand-motion tracking device. RESULTS: Overall, trainees made significant improvements in path length (P=.006), number of movements (P<.001), and time taken (P<.001). Analyzing the 3 courses separately, only trainees attending courses A and C made significant improvements. DISCUSSION: Objective validated methods can be used to assess learning of psychomotor skills on courses. In addition to providing participants with an insight into their skills, these data can be used to demonstrate course efficacy.

Cholecystectomy, Laparoscopic↗
PubMed2005

Does minimally invasive vein harvesting technique affect the quality of the conduit for coronary revascularization?

The effect of minimally invasive great saphenous vein harvest on patient morbidity (wound infection and other healing disturbances) has been extensively investigated, yet its impact on the quality of the venous conduit is less well known. This study aims to review the literature with regard to macroscopic quality, postoperative myocardial infarction rates, and angiographic patency of the minimally invasive versus conventionally harvested vein using meta-analytic techniques where appropriate. Results suggest that conduits are comparable in macroscopic quality with minimally invasively harvested veins requiring more repairs prior to grafting. Postoperative myocardial infarction rates were not significantly different between groups, which is supported by the limited evidence on angiographic patency.

Coronary Artery Bypass↗