Search PubMed⌕ Search

Biomedical subjects

A Darzi

Publications and source records attributed to A Darzi.

At least 55 records · Page 3Linked to original sources
PubMed2004

The simulated operating theatre: comprehensive training for surgical teams.

Surgical excellence is traditionally defined in terms of technical performance, with little regard for the importance of interpersonal communication and leadership skills. Studies in the aviation industry have stressed the role of human factors in causing error and, in an attempt to reduce the occurrence of adverse events, led to the organisation of simulation based training scenarios. Similar strategies have recently been employed for the surgical team with the development of a simulated operating theatre project. This enables technical and non-technical performance of the surgeon and circulating staff to be assessed by experts situated in an adjacent control room, and provides an opportunity for constructive feedback. The scenarios have good face validity and junior surgeons can benefit from the process of learning new technical skills in a realistic environment. The effect of external influences such as distractions, new technology, or a crisis scenario can also be defined, with the ultimate aim of reducing the number of adverse events arising in the real operating room.

Clinical Competence↗
PubMed2004

Laparoscopy for malignancy: current status.

The acceptance of laparoscopy for the management of oncologic disease has been slow because of initial fears regarding the effect of this new approach on the interaction between the patient and the tumor. Since the initial attempts at laparoscopic resection, experience and technology have improved in parallel, facilitating improvements in this area. Laparoscopic oncologic surgery has a role in the management of oncologic patients at all stages of disease. Good evidence exists that laparoscopy has become an invaluable staging tool in many upper gastrointestinal cancers as well as lymphomas. The specter of port-site recurrence has loomed over the use of a laparoscopic approach for curative resections. However, it is clear from many reported trials that the initial prevalence of port-site metastases was more a technical issue rather than a problem with laparoscopy. Current large, multicenter trials will report the true outcomes of laparoscopic colon cancer surgery and its comparison with open surgery. It does appear that laparoscopic cancer surgery is feasible, safe, and oncologically sound. We fully believe that laparoscopic cancer surgery will play an increasingly major role in the management of gastrointestinal malignancies.

Clinical Trials as Topic↗
PubMed2004

Anatomy: the future teaching of undergraduates.

The time devoted to the teaching of anatomy to medical students has long been under pressure. Much work has been devoted to how best to teach anatomy in both a time-efficient and cost-effective manner. This article discusses the main methods of teaching anatomy and their respective advantages and disadvantages as evidenced in the literature. Suggestions are made as to how best to teach anatomy to medical students in the future.

Anatomy↗
PubMed2004

[Laparoscopic and general surgery guided by open interventional magnetic resonance].

Interventional magnetic resonance (IMR) machines have produced unique opportunity for image-guided surgery. The open configuration design and fast pulse sequence allow virtual real time intraoperative scanning to monitor the progress of a procedure, with new images produced every 1.5 sec. This may give greater appreciation of anatomy, especially deep to the 2-dimensional laparoscopic image, and hence increase safety, reduce procedure magnitude and increase confidence in tumour resection surgery. The aim of this paper was to investigate the feasibility of performing IMR-image-guided general surgery, especially in neoplastic and laparoscopic field, reporting a single center -- St. Mary's Hospital (London, UK) -- experience. Procedures were carried out in a Signa 0.5 T General Elettric SP10 Interventional MR (General Electric Medical Systems, Milwaukee, WI, USA) with magnet-compatible instruments (titanium alloy instruments, plastic retractors and ultrasonic driven scalpel) and under general anesthesia. There were performed 10 excision biopsies of palpable benign breast tumors (on female patients), 3 excisions of skin sarcoma (dermatofibrosarcoma protuberans), 1 right hemicolectomy and 2 laparoscopic cholecystectomies. The breast lesions were localized with pre- and postcontrast (intravenous gadolinium DPTA) sagittal and axial fast multiplanar spoiled gradient recalled conventional Signa sequences; preoperative real time fast gradient recalled sequences were also obtained using the flashpoint tracking device. During right hemicolectomy intraoperative single shot fast spin echo (SSFSE) and fast spoiled gradient recalled (FSPGR) imaging of right colon were performed after installation of 150 cc of water or 1% gadolinium solution, respectively, through a Foley catheter; imaging was also obtained in an attempt to identify mesenteric lymph nodes intraoperatively. Concerning laparoscopic procedures, magnetic devices (insufflator, light source) were positioned outside scan room, the tubing and light head being passed through penetration panels. Intraoperative MR-cholangiography was performed using fast spin echo (SSFSE) techniques with minimal intensity projection 3-dimensional reconstruction. About skin sarcomas, 2 of them were skin recurrences of previously surgically treated sarcomas (all of them received preoperative biopsy) and the extent of the lesion was then determined using short tau inversion recovery (STIR) sequence. The skin was closed in each case without need for any plastic reconstruction. The breast lesions were visualized with both Signa and real-time imaging and all enhanced with contrast: 2 (20%) were visualized only after contrast enhancement; intraoperative real time imaging clearly demonstrated a resection margin in all cases. Maximum dimensions of breast specimens (range 8-50 mm, median 24.5 mm) were not significantly different from those measured by Signa (p>0.17, Student's paired t-test) or real time images (p>0.4): also there was no significant difference in lesion size between Signa and real time images (p>0.25). All postprocedure scans clearly demonstrated complete excision. The extent of the tumor at MR imaging was greater in each case than suggested by clinical examination. Adequate resection margins were planned using STIR sequences. Histological examination confirmed clear surgical margins of at least 1 cm in each case. During right hemicolectomy, both intraoperative SSFSE and FSPGR contrast imaging revealed the lesion and details of the colonic surface; imaging of the lymph node draining right colon was only partially successful, due to movement artifact. Concerning laparoscopic procedures, both FSE and SSFSE techniques produced reasonable images of the gallbladder and intrahepatic ducts, but the FSE imaging was of poor quality due to respiration artifact; however, SSFSE allowed visualization of the gallbladder and part of the common bile duct. About skin sarcomas, the extent of the tumor at MR imaging was greater in each case than suggested by clinical examination and in each case the complete tumor excision was confirmed. Histological examination confirmed clear surgical margins of at least 1 cm in each case. Intraoperative MR scanning reliably identifies palpable breast tumours and skin sarcomas and is sufficiently accurate to guide their surgical excision. Further work may be done to develop laparoscopic and open abdominal surgery as well.

Anesthesia, General↗
PubMed2004

Evaluation of the benefit of VR simulation in a multi-media web-based educational tool.

WebSET is an Internet based educational tool that can be used on any standard personal computer. It has been developed by a European collaboration and integrates high quality multimedia learning materials with VR simulation. The aim of this study was to evaluate the benefit of the VR simulation on the learning of procedure based psychomotor skills. Subjects were divided into three groups. The group that used the entire package including the VR simulation were superior to the group that used only the multimedia component in terms of the their procedural skills in the post-training assessment. Both groups performed better than the controls.

Computer-Assisted Instruction↗
PubMed2003

Validity and reliability of a virtual reality upper gastrointestinal simulator and cross validation using structured assessment of individual performance with video playback.

BACKGROUND: This study aims to evaluate the ability of an upper gastrointestinal virtual reality simulator to assess skills in endoscopy, and to validate its metrics using a video-endoscopic (VES) technique. METHODS: The 32 participants in this study were requested to undertake two cases on the simulator (Simbionix, Israel). Each module was repeated twice. The simulator's metrics of performance were used for analysis. two blinded observers rated performance watching the simulator's playback feature. RESULTS: There were 11 novices (group 1), 11 trainees with intermediate experience (10-50 procedures, group 2), and 10 experienced endoscopists (>200 procedures, group 3). There was a significant difference in the total time required to perform the procedure (p < 0.001), percentage of mucosa visualized (p < 0.001), percentage of pathologies visualized (p < 0.001), and number of inappropriate retroflexions (p = 0.015) across the three groups. The reliability of assessment on the simulator was greater than 0.80 for all parameters. The VES assessment also was able to discriminate performance across the groups (p < 0.001). There was a significant correlation between the VES score and the percentage of mucosa visualized (rho = 0.60; p < 0.001). CONCLUSIONS: The upper gastrointestinal simulator may be a useful tool for determining whether a trainee has achieved a desired level of competence in endoscopy. The next step will be to validate the VES score in real procedures.

Endoscopy, Gastrointestinal↗
PubMed2003

A study to validate the colonoscopy simulator.

BACKGROUND: The aim of this study was to investigate the relation between clinical experience and performance with regard to colonoscopic procedures performed on the HT Immersion Medical Colonoscopy Simulator. The hypothesis is that the performance of novice, intermediate, and experienced operators is different on simulators, just as it is on real patients. METHODS: 25 Postgraduate doctors were recruited and divided into three groups according to their level of colonoscopic experience. Candidates were asked at random to perform colonoscopy on module 3 or 4 of the HT Immersion Medical Colonoscopy Simulator. Modules 3 and 4 have built-in complex loops, and can demonstrate the candidate's ability either to avoid or undo the loop. Candidates in the first group, termed "novice," each had performed fewer than 10 colonoscopies and included four preregistration house officers (PRHOs), five specialist trainee resistrars (SpRs) and two consultants. This novice group had completed 80 episodes among them. In the second group, termed "intermediate," each candidate had performed between 11 and 100 colonoscopies, and the candidates included five SpRs and two research fellows. This intermediate group had completed 65 episodes. Members of the third group, termed "experienced" each had performed more than 101 colonoscopies, and included one SpR and six consultants. This experienced group had completed 45 episodes between them. A time result of 3,600 s (1 h) was used to denote perforation. RESULTS: The experienced group were shown to perform better than the intermediate group, which in turn performed better than the novice group. The assessment was based on multiple factors including time taken to complete the test, percentage of the colonic mucosa visualized, incidence of colonic perforations, and path length used. The results were highly significant statistically for all these factors ( p < 0.000) except in path length used. CONCLUSIONS: This study demonstrated that operators who differ in terms of their clinical experience and technical ability also differ in their performance of simulated colonoscopy. Thus, the findings have shown the simulator technology to be a powerful discriminator of manipulative skills in colonoscopy. The clinical differences that exist between novices and experts in terms of experience and technical expertise in endoscopic procedures are reflected by statistically significant differences in performance on the simulator. It is therefore reasonable to argue that improving proficiency on the simulator may translate into improvements in clinical practice. This study has validated the use of the HT Medical Immersion Colonoscopy Simulator to discriminate among subjects with different levels of experience.

Colonoscopy↗
PubMed2003

The effects of different viewing conditions on performance in simulated minimal access surgery.

This study aimed to assess performance in simulated minimal access surgery (MAS) tasks under a range of viewing conditions. MAS conventionally uses 2d viewing systems which produce a flat image. However, 3d viewing systems which produce stereoscopic depth information should in principle lead to better depth perception, and improve performance on tasks which require appropriate spatial representation of layout and depth. The study compared a novel 3d viewing system with a state of the art 2d viewing system and a direct viewing condition ('open surgery') as a point of reference. Tasks included pulling and cutting of threads using standard surgical instruments. Medical students (n = 16) were allocated to viewing conditions according to a Latin square and carried out 120 tasks each. Assessment was by means of a 3d movement tracking device providing a number of performance parameters (time on task, velocity, number of movements, distance travelled). In addition instrument movement was video-recorded and analysed by four observers to validate the tracking device. Results from tracking data and observer data were highly correlated (r > 0.85). While open surgery naturally scored highest, the key finding was the clearly superior performance in the 3d condition compared to 2d. Thus modern 3d viewing systems can improve performance in a realistic task.

Adult↗
PubMed2003

The effect of stress-inducing conditions on the performance of a laparoscopic task.

BACKGROUND: The availability of objective means for assessment of surgical skills has made it possible to evaluate the effect of adverse environmental conditions on surgical performance. METHODS: Participants performed a laparoscopic transfer task under five conditions: a simple verbal mathematical task (M), operating theatre background noise at 80 to 85 dB (N), performance as quickly as possible (T), all three stressors combined (A), and quiet conditions (Q). The effect of these conditions on performance was evaluated by using a motion analysis system and an error score. RESULTS: The study included 13 right-handed surgeons with varying levels of laparoscopic experience. There was a significant increase in the path length per movement of the right hand (p = 0.001) under T and a significant increase in the path length per movement of the left hand under M (p = 0.002), T (p = 0.01), and A (p = 0.02). A significantly higher number of errors occurred under all four stress-inducing conditions. The effect was more pronounced when all the stressors were applied in combination ( p = 0.001) followed by performance under M (p = 0.005), then T (p = 0.01) and N (p = 0.03). CONCLUSIONS: All three stressors led to impaired dexterity and an increase in the incidence of errors.

Adult↗
PubMed2003

Depth cue reliance in surgeons and medical students.

BACKGROUND: Depth perception is reduced in endoscopic surgery, although little is known about the effect this has on surgical performance. METHODS: To assess the role of depth cues, 45 subjects completed tests of depth cue reliance. Surgical skill was assessed using the Minimally Invasive Surgical Trainer-Virtual Reality, a previously validated laparoscopic simulator. RESULTS: We could demonstrate no difference in cue reliance for three depth cues--namely stereo, texture, and outline--between surgeons and medical students. Greater dominance on stereo for medical students was a positive finding and a negative finding for the surgeons when correlated with surgical performance. CONCLUSIONS: We suggest that surgeons learn to adapt to the nonstereo environment in MIS, and this is the first study to show evidence of this phenomenon. This difference in stereo reliance is a reflection of the experience that surgeons have with laparoscopy compared with medical students, who have none.

Adult↗
PubMed2003

Can tonic accommodation predict surgical performance?

BACKGROUND: Pilots undergo many visual tests for both selection and assessment, and we know that there are many similarities between pilots and surgeons. Hence, it would not be unreasonable to bring similar visual tests into surgery. Tonic accommodation (TA) is a stable parameter that is adopted by the eye in the absence of any stimulation. Over recent years, surgery has undergone change from traditional open surgery to minimally invasive procedures, bringing many advantages. However, not every surgeon has the ability to perform under conditions where the operative field is represented on a flat monitor. METHOD: We determined the TA values in medical students and then correlated this with their performance on a virtual reality surgical simulator. RESULTS: We found that TA values predicted the number of errors made with the dominant hand, accounting for 27% of the variance. CONCLUSION: The data suggest that TA may play a role in the individual differences that are noted when surgeons perform laparoscopic surgery. Further studies are needed to evaluate the exact role of TA in surgical performance.

Accommodation, Ocular↗
PubMed2003

Objective assessment of technical skills of surgical trainees in Hong Kong.

BACKGROUND: The need for assessment of technical skills is well recognized and objective methods of assessment are currently under investigation in the UK. The applicability of these assessment tools to trainees with a different training background in another country was examined. METHODS: Six bench-top models for basic surgical trainees (BSTs) and eight for higher surgical trainees (HSTs) (five in common) were assessed for construct validity in 70 subjects. Objective assessment methods included motion analysis using the Imperial College Surgical Assessment Device, Objective Structured Assessment of Technical Skills and Minimally Invasive Surgical Trainer in Virtual Reality. RESULTS: All models shared between BSTs and HSTs exhibited construct validity (range P = 0.050 to P < 0.001). Of the three modules for HSTs alone, only one gave significant results (small bowel anastomosis; P = 0.005). Reasons for this were sought. CONCLUSION: The methods of objective technical skills assessment of trainees in the UK are applicable to those in Hong Kong. Their use should be promoted and the tracking of skills development encouraged.

Adult↗
PubMed2003

Core biopsy versus FNAC for palpable breast cancers. Is image guidance necessary?

The aim of this study was to assess the efficacy of free-hand percutaneous core biopsy (FHCB) and to determine the role of fine needle aspiration cytology (FNAC) as diagnostic tools for palpable radiologically-suspicious breast lumps. This retrospective study was based on reviewing the clinical records of all patients diagnosed as having breast cancer between January 1999 and December 2000 and patients who had benign lesions, but suspicious breast imaging at triple assessment. Absolute sensitivity of FHCB for diagnosing cancer in palpable lesions was 98.7% compared with 51.3% for FNAC. The difference in the sensitivity of FHCB and FNAC was statistically significant (P<0.005, Wilcoxon matched pair test). Since 94.8% of radiologically-suspicious lumps were shown to be cancers, we advocate FHCB for all patients presenting with radiologically suspicious palpable lumps to our breast clinic. We also conclude that the sensitivity of FHCB for the diagnosis of malignancy in palpable radiologically-suspicious breast lesions is so high that image-guidance is unnecessary.

Biopsy, Needle↗
PubMed2003

Learning the skills of flexible sigmoidoscopy - the wider perspective.

BACKGROUND: Nurse-led gastrointestinal endoscopy is a priority clinical area in the UK. Endoscopic procedures are challenging to learn, requiring a combination of technical competence (manipulating a flexible endoscope and interpreting the findings) and interpersonal skills (engaging effectively with a conscious patient who is frequently apprehensive). This paper explores the potential of an innovative, scenario-based approach which links a simulated patient with a computer-driven virtual reality (VR) training device for flexible sigmoidoscopy. Within this safe yet realistic quasi-clinical environment, learners carry out the procedure while interacting with the 'patient'. Communication skills are assessed by simulated patients, while quantitative performance data relating to the procedure is generated automatically by the VR simulator. METHODS: This pilot study took place within a nurse practitioner endoscopy course. A mixed methodology combined qualitative and quantitative data (observation and interview studies, communication rating scales and a range of computer-generated output measures from the VR simulator) in a multifaceted evaluation. RESULTS: Seven nurses took part in the study. Participants found the scenarios to be a convincing and powerful learning experience. All experienced high levels of anxiety. Simulated patients identified strengths in participants' communication skills, together with areas for development. Simulator-based practice led to an improvement in objective performance measures. DISCUSSION: Scenario-based training provides a powerful learning experience, allowing participants to build their technical expertise and apply it within a holistic clinical context without the risk of causing harm. We used this pilot study as a springboard for discussions over wider implications of procedure-based skills training, locating it within the literature on expertise and situated learning.

Clinical Competence↗
PubMed2003

The use of handheld computers in scenario-based procedural assessments.

This paper describes the authors' experiences of using handheld computers within scenario-based formative assessments aimed at developing clinical procedural skills. Previous experiences of using paper forms in these assessments were problematic. Multiple paper forms were generated and data sets were sometimes incomplete. Forms adapted for use on handheld computers offer significant potential advantages over paper-based versions. These include streamlining the process of data collection, entry and retrieval, thereby reducing data loss and providing learners with immediate and cumulative feedback on their performance. All participants in this study found the Personal Digital Assistant (PDA) forms easy to use. Further adaptation, together with increased familiarity with PDA technology, will address users' feedback by providing more space for free text and a larger visual field. Technical expertise is required for the development and delivery of PDA-based forms, but their potential for use in formative and summative assessments is considerable.

Attitude of Health Personnel↗