ATLS versus ETC: time for a decision?
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Emergency Medical Services↗
Biomedical subjects
Ara Darzi
Publications and source records attributed to Ara Darzi.
Training junior operative residents in laparoscopic suturing skills is feasible and efficacious.
BACKGROUND: Laparoscopic suturing has been regarded as an advanced operative task, and courses to develop this skill are aimed at senior trainees and consultants. This study evaluates the role of laparoscopic suturing courses in the modern operative training curriculum. METHODS: The performance of 9 senior operative trainees (course A) was compared to that of 14 junior operative trainees (course B) at identical, 2-day laparoscopic suturing courses. Pre- and post-course assessments measured time taken, dexterity, and quality for the placement of 1 intracorporeal suture on synthetic bowel. Post-course data was compared to the performance of a group of 6 experts. RESULTS: The median number of laparoscopic procedures carried out unassisted was 130 for surgeons on course A, and 0 for those on course B. At the pre-course assessment, senior trainees (course A) were significantly faster, more dexterous, and had higher checklist scores then those on course B. Both groups had improved significantly by the end of each the course. Post-course comparison between the 2 groups showed equivalent path length and checklist scores, although group A remained faster (P = .003) and made fewer movements (P = .033). Senior trainees had similar performance data to the group of expert surgeons, although this was not the case for junior trainees. CONCLUSIONS: Endoscopic suturing is a task that can be learned by operative trainees during short skills courses, regardless of baseline laparoscopic experience. Skills training in laparoscopic suturing should thus not be reserved only for those contemplating advanced laparoscopic operation.
General Surgery↗
The human face of simulation: patient-focused simulation training.
Simulation is firmly established within health care training but often focuses on training for technical tasks and can overlook crucial skills such as professionalism and physician-patient communication. The authors locate this paper within current developments in health care and relate it to the literature on simulation. They make the case for placing real human "patients" (played by actors) within simulation environments, thereby ensuring that the training experience remains rooted in actual practice. By practicing repeatedly within a safe environment, technical skills, communication with patients and team members, decision making, and clinical judgment may all be practiced and mastered while preserving patient safety. In elaborating this concept of patient-focused simulation (PFS), the authors draw on work already published by their group and several recent studies that are in review. These explore PFS in low, medium, and high complexity settings. Important or rare situations can be recreated and practiced, as well as key procedures required across a range of experience levels and clinical specialties. Finally, the case is made for curriculum redesign to ensure that simulator-based technical skills training and assessment take place within an authentic context that reflects the wider elements of clinical practice.
Computer Simulation↗
Fast-track failure after cardiac surgery: development of a prediction model.
OBJECTIVE: Risk factors for unsuccessful fast-tracking of cardiac surgery patients have not been collectively defined in the literature. The aim of this study was to determine risk factors for fast-track failure and incorporate them into a predictive fast-track failure score. DESIGN: Prospective observational study. SETTING: Cardiothoracic Department of St Mary's Hospital, London. PATIENTS: Data were collected from April 2003 to April 2005 including 1,084 patients undergoing heart surgery who were admitted into the fast-track unit. INTERVENTIONS: Multifactorial logistic regression was used to develop a propensity score for estimating the likelihood of fast-track failure. MEASUREMENTS AND MAIN RESULTS: One hundred and sixty-nine patients failed fast-track management (15.6%). Independent predictors for fast-track failure were impaired left ventricular function with or without recent acute coronary syndrome (odds ratios 2.89 and 1.65 respectively), re-do operation (one, two, or more vs. none, odds ratio 1.75, 7.98), extracardiac arteriopathy (odds ratio 2.63), preoperative intra-aortic balloon pump (odds ratio 3.09), raised serum creatinine in micromol/L (120-150, >150 vs. <120, odds ratio 1.57, 11.24), and nonelective (odds ratio 3.43) and complex surgery (odds ratio 2.70). Model validation showed very good discrimination (area under the curve = 0.815) and calibration (ĉ statistic = 8.527, p = .129). CONCLUSIONS: The fast-track failure score incorporates several preoperative factors and has been successfully internally validated; after undergoing external validation and possible recalibration it may be used as a tool to facilitate planning and flow of cardiac surgery patients, based on the predicted probability of failure. Application of this score may limit fast-track failure rates and help to reduce morbidity and cost.
Aged↗
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↗
Surgical crisis management skills training and assessment: a simulation[corrected]-based approach to enhancing operating room performance.
BACKGROUND: Intraoperative surgical crisis management is learned in an unstructured manner. In aviation, simulation training allows aircrews to coordinate and standardize recovery strategies. Our aim was to develop a surgical crisis simulation and evaluate its feasibility, realism, and validity of the measures used to assess performance. METHODS: Surgical trainees were exposed to a bleeding crisis in a simulated operating theater. Assessment of performance consisted of a trainee's technical ability to control the bleeding and of their team/human factors skills. This assessment was performed in a blinded manner by 2 surgeons and one human factors expert. Other measures consisted of time measures such as time to diagnose the bleeding (TD), inform team members (TT), achieve control (TC), and close the laceration (TL). Blood loss was used as a surrogate outcome measures. RESULTS: There were considerable variations within both senior (n = 10) and junior (n = 10) trainees for technical and team skills. However, while the senior trainees scored higher than the juniors for technical skills (P = 0.001), there were no differences in human factors skills. There were also significant differences between the 2 groups for TD (P = 0.01), TC (P = 0.001), and TL (0.001). The blood loss was higher in the junior group. CONCLUSIONS: We have described the development of a novel simulated setting for the training of crisis management skills and the variability in performance both in between and within the 2 groups.
Blood Loss, Surgical↗
An evidence-based virtual reality training program for novice laparoscopic surgeons.
OBJECTIVE: To develop an evidence-based virtual reality laparoscopic training curriculum for novice laparoscopic surgeons to achieve a proficient level of skill prior to participating in live cases. SUMMARY BACKGROUND DATA: Technical skills for laparoscopic surgery must be acquired within a competency-based curriculum that begins in the surgical skills laboratory. Implementation of this program necessitates the definition of the validity, learning curves and proficiency criteria on the training tool. METHODS: The study recruited 40 surgeons, classified into experienced (performed >100 laparoscopic cholecystectomies) or novice groups (<10 laparoscopic cholecystectomies). Ten novices and 10 experienced surgeons were tested on basic tasks, and 11 novices and 9 experienced surgeons on a procedural module for dissection of Calot triangle. Performance of the 2 groups was assessed using time, error, and economy of movement parameters. RESULTS: All basic tasks demonstrated construct validity (Mann-Whitney U test, P < 0.05), and learning curves for novices plateaued at a median of 7 repetitions (Friedman's test, P < 0.05). Expert surgeons demonstrated a learning rate at a median of 2 repetitions (P < 0.05). Performance on the dissection module demonstrated significant differences between experts and novices (P < 0.002); learning curves for novice subjects plateaued at the fourth repetition (P < 0.05). Expert benchmark criteria were defined for validated parameters on each task. CONCLUSION: A competency-based training curriculum for novice laparoscopic surgeons has been defined. This can serve to ensure that junior trainees have acquired prerequisite levels of skill prior to entering the operating room, and put them directly into practice.
Benchmarking↗
A comparison of hand-sewn versus stapled ileal pouch anal anastomosis (IPAA) following proctocolectomy: a meta-analysis of 4183 patients.
OBJECTIVE: Using meta-analytical techniques, the study compared postoperative adverse events and functional outcomes of stapled versus hand-sewn ileal pouch-anal anastomosis (IPAA) following restorative proctocolectomy. BACKGROUND: The choice of mucosectomy and hand-sewn versus stapled pouch-anal anastomosis has been a subject of debate with no clear consensus as to which method provides better functional results and long-term outcomes. METHODS: Comparative studies published between 1988 and 2003, of hand-sewn versus stapled IPAA were included. Endpoints were classified into postoperative complications and functional and physiologic outcomes measured at least 3 months following closure of ileostomy or surgery if no proximal diversion was used, quality of life following surgery, and neoplastic transformation within the anal transition zone. RESULTS: Twenty-one studies, consisting of 4183 patients (2699 hand-sewn and 1484 stapled IPAA) were included. There was no significant difference in the incidence of postoperative complications between the 2 groups. The incidence of nocturnal seepage and pad usage favored the stapled IPAA (odds ratio [OR] = 2.78, P < 0.001 and OR = 4.12, P = 0.007, respectively). The frequency of defecation was not significantly different between the 2 groups (P = 0.562), nor was the use of antidiarrheal medication (OR = 1.27, P = 0.422). Anorectal physiologic measurements demonstrated a significant reduction in the resting and squeeze pressure in the hand-sewn IPAA group by 13.4 and 14.4 mm Hg, respectively (P < 0.018). The stapled IPAA group showed a higher incidence of dysplasia in the anal transition zone that did not reach statistical significance (OR = 0.42, P = 0.080). CONCLUSIONS: Both techniques had similar early postoperative outcomes; however, stapled IPAA offered improved nocturnal continence, which was reflected in higher anorectal physiologic measurements. A risk of increased incidence of dysplasia in the ATZ may exist in the stapled group that cannot be quantified by this study. We describe a decision algorithm for the choice of IPAA, based on the relative risk of long-term neoplastic transformation.
Anastomosis, Surgical↗
Gaze-contingent control for minimally invasive robotic surgery.
OBJECTIVE: Recovering tissue depth and deformation during robotically assisted minimally invasive procedures is an important step towards motion compensation, stabilization and co-registration with preoperative data. This work demonstrates that eye gaze derived from binocular eye tracking can be effectively used to recover 3D motion and deformation of the soft tissue. METHODS: A binocular eye-tracking device was integrated into the stereoscopic surgical console. After calibration, the 3D fixation point of the participating subjects could be accurately resolved in real time. A CT-scanned phantom heart model was used to demonstrate the accuracy of gaze-contingent depth extraction and motion stabilization of the soft tissue. The dynamic response of the oculomotor system was assessed with the proposed framework by using autoregressive modeling techniques. In vivo data were also used to perform gaze-contingent decoupling of cardiac and respiratory motion. RESULTS: Depth reconstruction, deformation tracking, and motion stabilization of the soft tissue were possible with binocular eye tracking. The dynamic response of the oculomotor system was able to cope with frequencies likely to occur under most routine minimally invasive surgical operations. CONCLUSION: The proposed framework presents a novel approach towards the tight integration of a human and a surgical robot where interaction in response to sensing is required to be under the control of the operating surgeon.
Algorithms↗
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↗
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↗
Compression anastomoses revisited.
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Alloys↗
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↗
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↗
New professional roles in surgery.
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Clinical Competence↗
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↗
Gaze-contingent soft tissue deformation tracking for minimally invasive robotic surgery.
The introduction of surgical robots in Minimally Invasive Surgery (MIS) has allowed enhanced manual dexterity through the use of microprocessor controlled mechanical wrists. Although fully autonomous robots are attractive, both ethical and legal barriers can prohibit their practical use in surgery. The purpose of this paper is to demonstrate that it is possible to use real-time binocular eye tracking for empowering robots with human vision by using knowledge acquired in situ. By utilizing the close relationship between the horizontal disparity and the depth perception varying with the viewing distance, it is possible to use ocular vergence for recovering 3D motion and deformation of the soft tissue during MIS procedures. Both phantom and in vivo experiments were carried out to assess the potential frequency limit of the system and its intrinsic depth recovery accuracy. The potential applications of the technique include motion stabilization and intra-operative planning in the presence of large tissue deformation.
Artificial Intelligence↗
Subject specific finite element modelling of the levator ani.
Understanding of the dynamic behaviour of the levator ani is important to the assessment of pelvic floor dysfunction. Whilst shape modelling allows the depiction of 3D morphological variation of the levator ani between different patient groups, it is insufficient to determine the underlying behaviour of how the muscle deforms during contraction and strain. The purpose of this study is to perform a subject specific finite element analysis of the levator ani with open access magnetic resonance imaging. The method is based on a Mooney-Rivlin hyperelastic model and permits dynamic study of subjects under natural physiological loadings. The value of the proposed modelling framework is demonstrated with dynamic 3D data from nulliparous, female subjects.
Computer Simulation↗