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Biomedical subjects

A Darzi

Publications and source records attributed to A Darzi.

At least 37 records · Page 2Linked to original sources
PubMed2005

Sentinel node biopsy can replace four-node-sampling in staging early breast cancer.

AIM: Four-node axillary sampling for breast cancer is an established method of staging the axilla in the United Kingdom. We report the sensitivity of sentinel node (SN) biopsy and compare it with that of four-node sampling. METHODS: SN identification was attempted in 234 consecutive patients with unifocal breast cancers up to 25 mm in diameter on pre-operative ultrasound. A combination of isotope-labelled nanocolloid and patent blue dye techniques were used and SN were identified in 221 (94.5%). All patients underwent back-up four-node sampling and those with positive sentinel nodes on frozen section (FS) underwent immediate full axillary clearance. RESULTS: Among those patients who had SN successfully identified, an average of 1.38 SN were identified per patient. Histological examination of the SN alone would have identified all node-positive patients that the four-node sample identified. CONCLUSION: In patients who have SN identified, four-node axillary sampling does not provide any additional information.

Axilla↗
PubMed2005

Laparoscopic surgery for colon cancer.

Acceptance of laparoscopy for the management of oncological disease has been slow due to the increased complexity of the technique, requirement of technological advances, and fears for the oncological safety of the approach. Laparoscopic oncological surgery has a role in the management of oncological patients at all stages of disease. Good evidence exists for the laparoscopic approach being a viable option for colon cancer patients. Current large multicenter trials will report the true outcomes of laparoscopic colon cancer surgery and how it compares with open surgery. This article examines some of the parameters by which laparoscopic colectomy will be judged.

Clinical Trials as Topic↗
PubMed2004

Robot-assisted laparoscopic Heller cardiomyotomy: preliminary UK results.

BACKGROUND/AIM: Laparoscopic Heller cardiomyotomy is an established modality in the surgical treatment of patients having achalasia cardia. We present our initial experience in robot-assisted laparoscopic Heller cardiomyotomy without addition of an antireflux procedure and discuss the relative merits and disadvantages of the procedure. PATIENTS AND METHODS: Five patients underwent robot-assisted laparoscopic Heller cardiomyotomy between August 2001 and October 2002. The diagnosis had been confirmed by radiology and manometry in all patients prior to surgery. RESULTS: All procedures were completed successfully using the robotic system, without conversion to open procedure. Mucosal perforation occurred in 1 patient and was sutured robotically. The average operative time was 114.8 (range 65-160) min which is comparable to laparoscopic procedures. After a mean follow-up period of 9.4 (range 3-17) months, 4 patients remained completely asymptomatic, and 1 patient has benefited from symptomatic improvement. CONCLUSIONS: The enhanced dexterity and the high-quality three-dimensional vision available with robot-assisted surgery make the application of this technology highly suitable for Heller cardiomyotomy. The minimal lateral and posterior dissection due to the wristed instruments avoids the need for an antireflux procedure.

Adult↗
PubMed2004

Bimodal assessment of laparoscopic suturing skills: construct and concurrent validity.

BACKGROUND: The assessment of technical skills should provide objective feedback and judge suitability of progress during training. The aim of this study was to validate two objective assessment techniques for laparoscopic suturing and demonstrate a correlation between them. METHODS: Six experts, seven surgeons skilled in laparoscopic suturing, and 13 with no laparoscopic suturing skills were asked to place two or three intracorporeal sutures on a synthetic suture pad. The latter group was given video-based instructions prior to the execution of the sutures. Ergonomic conditions were standardized for all subjects. The procedures were recorded on videotape and two blinded observers rated the first suture of each subject on a 29-point checklist. A motion analysis system, Imperial College Surgical Assessment Device, was used to assess psychomotor skills. RESULTS: There was a significant difference in the time taken (p = 0.000) and total path length (p = 0.000) per suture across the groups. There were also a significant difference in the total checklist score (p = 0.000) and its individual categories. The was a strong correlation between the total path length and the total checklist score (coefficient, 0.78; p < 0.001). CONCLUSIONS: A combination of the motion analysis system and the checklist would make the process of formative feedback during the learning of intracorporeal suturing objective and comprehensive.

Clinical Competence↗
PubMed2004

An innovative method for the assessment of skills in lower gastrointestinal endoscopy.

BACKGROUND: Although virtual reality (VR) simulators can be used ability to objectively assess skills in endoscopy, the evaluation is solely quantitative. We have developed a novel method for the objective assessment of technical skills in lower gastrointestinal (GI) endoscopy that incorporates qualitative as well as quantitative measures. METHODS: We developed a virtual endoscopy suite by deconstructing the VR simulator to enable a more realistic and ergonomic placement of the monitor. Trainee endoscopists with varying levels of experience performed the case 4 task of the simulator. Ten essential components of endoscopic performance were rated on a five-point Likert scale (global score) by three independent observers. These observers viewed two videos (one showing scope handling and the other showing the monitor image), which were synchronized and played simultaneously. RESULTS: The study population comprised six experts (group 1, > 200 procedures), seven subjects with intermediate experience (group 2, 20-80 procedures), and seven novices (group 3, 1-10 procedures). The global score was found to discriminate the level of skills across all three groups (p < 0.001). There were significant differences between groups 1 and 2 (p = 0.003) and groups 2 and 3 (p = 0.004). There was a significant correlation between the global score and the percentage of red-out (without vision) as recorded by the simulator (correlation coefficients = -0.61, p = 0.004). CONCLUSION: This novel method for the assessment of technical skills in lower GI endoscopy has construct validity and high interrater reliability.

Clinical Competence↗
PubMed2004

Robotics in colorectal surgery.

Minimally invasive surgery has been shown to offer many advantages to general surgical patients but has not been widely adopted for colorectal disease. Initial fears surrounding the oncological safety of laparoscopic colectomies have largely subsided but the technical challenges still remain. Surgical robots or telemanipulators present the laparoscopic surgeon with unrivaled dexterity and vision, which may allow colonic resections to be completed with greater ease. Although initial studies suggest promising results using currently available systems, it will take further time for patient benefits to be proven, therefore justifying the greater expense of operating with this new technology.

Colonic Diseases↗
PubMed2004

The learning curve for a colonoscopy simulator in the absence of any feedback: no feedback, no learning.

BACKGROUND: The hypothesis of this study is that working on the simulator without a structured feedback does not change performance; hence, any effects shown after structured feedback would amount to useful learning of the procedure. The aim was to investigate the learning curve for the HT Immersion Medical Colonoscopy Simulator without any structured feedback. This could then be potentially applied to validate the learning curve on the simulator when structured feedback is provided. There are no previous studies on this matter. METHODS: Candidates were asked to perform colonoscopy on the HT Immersion Medical Colonoscopy Simulator. Modules 3 and 4 were used at random. In total, each candidate was asked to perform five consecutive virtual colonoscopies on the same module. These five episodes were collectively referred to as one trial. A time result of 3,600 sec (1 h) was used to denote perforation. No guidance or feedback was given to candidates before, during, or after each procedure. A total of 26 postgraduate doctors were recruited, including nine research fellows, five preregistration house officers, six specialist registrars, and six consultants. Fourteen candidates recorded five attempts each (i.e., one trial each) on the same module of the colonoscopy simulator (14 trials over 70 episodes). Another 12 candidates recorded five attempts (i.e., one trial each) on two modules of the colonoscopy simulator (24 trials over 120 episodes). Hence, 190 episodes were recorded in total, representing 38 trials. RESULTS: There was no improvement in performance on the simulator from first attempt to the fifth in the absence of feedback. If there was any initial gain in any measurable outcome, this was lost in subsequent attempts indicating lack of learning. The outcomes measured included time taken to complete the test, percentage of the mucosa visualized, depth of the instrument inserted, and the path length used. The results were statistically significant for all outcomes. CONCLUSIONS: This study demonstrates that in the absence of feedback, it is not possible to improve performance on the HT Immersion Medical Colonoscopy Simulator. Thus, there is no learning curve for the machine. The information from this study is vital for using the simulators in training and assessment because any improvement in learning curves shown after training on simulators can be presumed to be due to learning the procedure and not the simulator.

Clinical Competence↗
PubMed2004

Dexterity enhancement with robotic surgery.

BACKGROUND: The aim of this study was to quantify the extent of dexterity enhancement in robotic surgery as compared to laparoscopic surgery. METHODS: Ten surgeons with varying laparoscopic suturing experience were asked to place three sutures on a suture pad. The sutures were placed laparoscopically, robotically with 2-D vision and robotically with 3-D vision. The da Vinci systems Application Programming Interface (API) was used for positional data. A validated motion analysis system was used for data retrieval for the laparoscopic task. Custom software was developed for data analysis. RESULTS: Compared to laparoscopic suturing, when the task was undertaken robotically with 2-D vision there was a 20% reduction in the time taken but this was not significant (p = 0.07). There was a 55% reduction in the path traveled by the right hand (p = 0.01) and a 45% reduction in the path traveled by the left hand (p = 0.008). When the task was undertaken robotically with 3-D vision, there was a 40% reduction in the time taken (p = 0.01). There was a 70% reduction in the path traveled by right hand (p = 0.008) and a 55% reduction by the left hand (p = 0.08). CONCLUSIONS: The presence of wristed instrumentation, tremor abolition, and motion scaling enhance dexterity by nearly 50% as compared to laparoscopic surgery. 3-D vision enhances dexterity by a further 10-15%. In addition, the presence of 3-D vision results in a 93% reduction in skills-based errors.

Clinical Competence↗
PubMed2004

The benefits of stereoscopic vision in robotic-assisted performance on bench models.

BACKGROUND: Previous studies have failed to establish clear advantages for the use of stereoscopic visualization systems in minimal-access surgery. The aim of this study was to objectively assess whether stereoscopic visualization improves performance on bench models using the da Vinci robotic system. METHODS: Eleven surgeons carried out a series of four tasks. Positional data streamed from the da Vinci system was analyzed by means of a previously validated custom-designed software-package. An independent blinded observer scored errors. Statistical analysis included the Wilcoxon signed rank test. A p < 0.05 was deemed significant. RESULTS: We found significant improvements in all tasks and for all parameters (p < 0.05). In addition, a significantly lower number of errors was scored using the stereoscopic mode as compared to the standard two-dimensional image (p < 0.001). CONCLUSION: Robotic-assisted performance on bench models is more efficient and accurate using stereoscopic visualization.

Data Display↗
PubMed2004

Laparoscopic virtual reality and box trainers: is one superior to the other?

BACKGROUND: Virtual reality (VR) simulators now have the potential to replace traditional methods of laparoscopic training. The aim of this study was to compare the VR simulator with the classical box trainer and determine whether one has advantages over the other. METHODS: Twenty four novices were tested to determine their baseline laparoscopic skills and then randomized into the following three group: LapSim, box trainer, and no training (control). After 3 weekly training sessions lasting 30-min each, all subjects were reassessed. Assessment included motion analysis and error scores. Nonparametric tests were applied, and p < 0.05 was deemed significant. RESULTS: Both trained groups made significant improvements in all parameters measured ( p < 0.05). Compared to the controls, the box trainer group performed significantly better on most of the parameters, whereas the LapSim group performed significantly better on some parameters. There were no significant differences between the LapSim and box trainer groups. CONCLUSIONS: LapSim is effective in teaching skills that are transferable to a real laparoscopic task. However, there appear to be no substantial advantages of one system over the other.

Adult↗
PubMed2004

Qualitative and quantitative analysis of the learning curve of a simulated surgical task on the da Vinci system.

BACKGROUND: Robotic telemanipulation systems provide solutions to the problems of less dexterity and visual constraints of minimally invasive surgery (MIS). However, their influence over surgeons' dexterity and learning curve needs to be assessed. We present motion analysis as an objective method to measure performance and learning progress.METHODS. Thirteen surgeons completed five synthetic small bowel anastomoses using the da Vinci system. Objective Structured Assessment of Technical Skills (OSATS) allowed qualitative analysis. Quantitative analysis used API software of the system to retrieve real-time robotic signal data of time, path length, and number of movements. Wilcoxon signed ranks test was used for statistical analysis. A p value <0.05 was considered significant.RESULTS. OSATS global scores were 18.6 points for the first attempt and 26 for the fifth attempt ( p < 0.02, Cronbach's alpha = 0.894). Paired data of motion analysis for attempts 1 vs 5 showed significant change: time taken 3507 sec and 2287 sec ( p < 0.008), total number of movements 2411 and 1387 ( p = 0.01), total path length 21,630 cm and 13,941 cm ( p = 0.01).CONCLUSIONS. A rapid learning curve to a competent level using the da Vinci system is possible aided by the system's intuitive motion. Motion analysis is a useful tool to measure performance in the da Vinci system compared to OSATS and time alone.

Anastomosis, Surgical↗
PubMed2004

Laparoscopic skills training and assessment.

BACKGROUND: The introduction of laparoscopic techniques to general surgery was associated with many unnecessary complications, which led to the development of skills laboratories to train novice laparoscopic surgeons. This article reviews the tools currently available for training and assessment in laparoscopic surgery. METHODS: Medline searches were performed to identify articles with combinations of the following key words: laparoscopy, training, curriculum, virtual reality and assessment. Further articles were obtained by manually searching the reference lists of identified papers. RESULTS: Current training involves the use of box trainers with either innate models or animal tissues; it lacks objective assessment of skill acquisition. Virtual reality simulators have the ability to teach laparoscopic psychomotor skills, and objective assessment is now possible using dexterity-based and video analysis systems. CONCLUSION: The tools are now available for the development of a structured, competency-based, laparoscopic surgical training programme.

Clinical Competence↗
PubMed2004

Objective evaluation of the effect of noise on the performance of a complex laparoscopic task.

BACKGROUND: Noise in operating rooms has been found to be much higher than the recommended level of 45 dB. The aim of this study was to objectively evaluate the effect of noise and music on the performance of a complex surgical task. METHODS: Twelve surgeons with varying experience in laparoscopic suturing undertook 3 sutures in a laparoscopic trainer under 3 conditions: quiet, noise at 80 to 85 dB, and music. Other than the test conditions, all other conditions were standardized. A validated motion analysis system was used to assess performance. The tasks were recorded by video and played back to 2 blinded observers who rated the surgeons' performance on a global rating scale by observing the tasks for accuracy, knot quality, and number of nonpurposeful movements. RESULTS: Time taken for the tasks (P=.78), total number of movements (P=.78), total path length (P=.47), global score (P=.54), accuracy, and knot quality remained unchanged across the 3 conditions. The main study measures had a high test-retest reliability and internal consistency. No learning effect was seen across the 3 conditions. CONCLUSIONS: Surgeons can effectively "block out" noise and music. This is probably due to the high levels of concentration required for the performance of a complex surgical task. Future research should focus on the effect of these conditions on communication in the operating room.

Adult↗
PubMed2004

Simulation and clinical practice: strengthening the relationship.

INTRODUCTION: This discussion paper argues for a creative synthesis between simulation and clinical practice, where an iterative process of continual interaction ensures that skills are learned and reinforced within the context of everyday professional life. BACKGROUND: Evidence is mounting that long-established approaches to surgical training are no longer acceptable in the current ethical and professional climate. This paper considers alternatives to the traditional approach of 'learning by doing' in a clinical context, focusing on recent developments in the technology of simulation and virtual reality. Clinical expertise is a complex phenomenon and no single theory can account for its acquisition. After a brief contextualising overview, Vygotsky's 'zone of proximal development' is proposed as a conceptual framework for task-based surgical learning that takes place within skills laboratories. The discussion is located within a wider context of educational theory, drawing on current thinking about situated learning and apprenticeship. The notion of 'legitimate peripheral participation' in a complex professional environment places technical skill alongside a range of other competencies that are necessary to safe practice. CONCLUSIONS: Simulation offers a safe environment within which learners can repeatedly practise a range of clinical skills without endangering patients. Comprehensive simulated environments allow a move away from isolated tasks to more complex clinical situations, recreating many of the challenges of real life. Such simulations, however, can operate in isolation from their clinical context, ignoring the learning needs of individuals within a real health care environment. To realise its full potential as a learning aid, simulation must be used alongside clinical practice and linked closely with it.

Clinical Competence↗
PubMed2004

Robot-assisted laparoscopic adrenalectomy: preliminary UK results.

OBJECTIVE: To describe the results of our first two cases of laparoscopic adrenalectomy using the da Vinci surgical system (Intuitive Surgical, Inc., Mountain View, CA, USA). PATIENTS AND METHODS: Amongst 75 robot-assisted procedures performed at our institution, two patients underwent robot-assisted laparoscopic adrenalectomy. The set-up time, procedure time, hospital stay, complications and outcomes were recorded. RESULTS: Both operations were completed successfully using the robot; the mean (range) set-up time was 31 (25-37) min and mean procedure time 118.5 (107-130) min. One patient had a postoperative pulmonary embolus and was discharged 5 days after surgery; the second patient was discharged after 3 days. There were no intraoperative complications; both patients were well at the 1-year follow-up. CONCLUSIONS: Robot-assisted laparoscopic adrenalectomy is technically feasible and can be conducted efficiently and safely with the da Vinci surgical system.

Adenoma↗
PubMed2004

Deranged smooth muscle alpha-actin as a biomarker of intestinal pseudo-obstruction: a controlled multinational case series.

BACKGROUND AND AIMS: Chronic idiopathic intestinal pseudo-obstruction (CIIP) is a severe motility disorder associated with significant morbidity. Several histopathological (neuropathic and myopathic) phenotypes have been described but only a single adult with jejunal smooth (circular) muscle alpha-actin deficiency. We present a prospective multinational case series investigating smooth muscle alpha-actin deficiency as a biomarker of this disease. METHODS: A total of 115 fully clinically and physiologically (including prolonged (24 hour) ambulatory jejunal manometry) characterised CIIP patients from three European centres were studied. Immunohistochemical localisation of actins and other cytoskeletal proteins were performed on laparoscopic full thickness jejunal biopsies and compared with adult controls. Distribution of alpha-actin was also characterised in other gut regions and in the developing human alimentary tract. RESULTS: Twenty eight of 115 (24%) CIIP patient biopsies had absent (n = 22) or partial (n = 6) jejunal smooth muscle alpha-actin immunostaining in the circular muscle layer. In contrast, smooth muscle alpha-actin staining was preserved in the longitudinal muscle and in adult jejunal controls (n = 20). Comparative study of other adult alimentary tract regions and fetal small intestine, suggested significant spatial and temporal variations in smooth muscle alpha-actin expression. CONCLUSIONS: The ability to modulate alpha-smooth muscle actin expression, evident in development, is maintained in adult life and may be influenced by disease, rendering it a valuable biomarker even in the absence of other structural abnormalities.

Actins↗