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Ara Darzi

Publications and source records attributed to Ara Darzi.

At least 73 records · Page 4Linked to original sources
PubMed2004

Comparison of bench test evaluations of surgical skill with live operating performance assessments.

BACKGROUND: Attempts at assessing surgical proficiency have generally used laboratory simulation to evaluate skill. The aim of this study was to compare technical ability as measured on a bench simulation with actual operative performance. STUDY DESIGN: Twenty-two general surgeons and trainees were recruited: consultants (n = 4), specialist registrars (n = 14), and senior house officers (n = 4). They were assessed while performing a saphenofemoral dissection on an anesthetized patient in the operating theater, and performing the same procedure on an inanimate model within the laboratory. The Objective Structured Assessment of Technical Skill method, consisting of a 7-parameter global rating (maximum score 35) and 17-point step-by-step checklist (maximum score 17) was used to measure performance in both environments. Face, content, and construct validity of the synthetic model were established as part of this study. RESULTS: There was a significant relationship between technical skill as measured on the bench test model and performance within the operating theater with respect to both global rating (Spearman correlation coefficient 0.824, p < 0.001; alpha coefficient 0.89) and checklist ratings (r = 0.514, p < 0.02; alpha coefficient 0.68) rating assessments. Global rating scores correlated with experience for both operative (r = 0.822, p < 0.001) and bench (r = 0.515, p < 0.05) settings. There was no difference in level of measured performance between operating theater and bench model (global rating mean 23.25 +/- 6.66 versus 23.75 +/- 5.62, respectively; paired t-test p = 0.559). CONCLUSIONS: Assessment of technical skill using inanimate procedural simulation translates to actual surgical performance within the operating theater. This further validates use of bench test evaluations to measure surgical technical ability.

Clinical Competence↗
PubMed2004

Robotic assisted surgery. Part One.

Since the first laparoscopic cholecystectomies were performed by Muhe in 1986 and Mouret in 1987, minimal access surgery has been widely accepted and applied to many procedures. By the end of the 1990s, surgical robots had emerged in operating theatres around the world. This technology has the potential to revolutionise minimal access surgery.

Humans↗
PubMed2004

Robotic surgery: a review.

Minimally invasive techniques have revolutionized surgery by reducing surgical trauma and therefore hospital stay and subsequently cost. There are limitations, however. Robot-assisted surgery endeavours to minimize these technical hindrances and so allow better, more precise surgical practise while still minimizing surgical trauma.

Forecasting↗
PubMed2004

Real-time synchronization of kinematic and video data for the comprehensive assessment of surgical skills.

Surgical dexterity in operating theatres has traditionally been assessed subjectively. Electromagnetic (EM) motion tracking systems such as the Imperial College Surgical Assessment Device (ICSAD) have been shown to produce valid and accurate objective measures of surgical skill. To allow for video integration we have modified the data acquisition and built it within the ROVIMAS analysis software. We then used ActiveX 9.0 DirectShow video capturing and the system clock as a time stamp for the synchronized concurrent acquisition of kinematic data and video frames. Interactive video/motion data browsing was implemented to allow the user to concentrate on frames exhibiting certain kinematic properties that could result in operative errors. We exploited video-data synchronization to calculate the camera visual hull by identifying all 3D vertices using the ICSAD electromagnetic sensors. We also concentrated on high velocity peaks as a means of identifying potential erroneous movements to be confirmed by studying the corresponding video frames. The outcome of the study clearly shows that the kinematic data are precisely synchronized with the video frames and that the velocity peaks correspond to large and sudden excursions of the instrument tip. We validated the camera visual hull by both video and geometrical kinematic analysis and we observed that graphs containing fewer sudden velocity peaks are less likely to have erroneous movements. This work presented further developments to the well-established ICSAD dexterity analysis system. Synchronized real-time motion and video acquisition provides a comprehensive assessment solution by combining quantitative motion analysis tools and qualitative targeted video scoring.

Biomechanical Phenomena↗
PubMed2004

Soft tissue deformation using a Hierarchical Finite Element Model.

Simulating soft tissue deformation in real-time has become increasingly important in order to provide a realistic virtual environment for training surgical skills. Several methods have been proposed with the aim of rendering in real-time the mechanical and physiological behaviour of human organs, one of the most popular being Finite Element Method (FEM). In this paper we present a new approach to the solution of the FEM problem introducing the concept of parent and child mesh within the development of a hierarchical FEM. The online selection of the child mesh is presented with the purpose to adapt the mesh hierarchy in real-time. This permits further refinement of the child mesh increasing the detail of the deformation without slowing down the simulation and giving the possibility of integrating force feedback. The results presented demonstrate the application of our proposed framework using a desktop virtual reality (VR) system that incorporates stereo vision with integrated haptics co-location via a desktop Phantom force feedback device.

Connective Tissue↗
PubMed2003

The surgical error examination is a novel method for objective technical knowledge assessment.

BACKGROUND: Objective analysis of surgical skill is necessary. A novel method of assessment using simple error analysis in synthetic models is examined for construct validity. METHODS: Two examination protocols were devised using synthetic models. These contained either a purpose made error or were representative of good surgical practice. Protocol one contained models of skin closure and minor operations. Protocol two in addition more complex procedures. Face validity was established by the approval of senior surgeons. Junior surgeons were recruited to undertake the assessment. A p value of less than 0.05 was deemed to be significant. RESULTS: Eighty-nine surgeons were recruited. Both protocol one and two were able to discriminate between groups at statistically significant levels. CONCLUSIONS: Construct validity has been established by showing that error analysis is able to distinguish surgeons with varying levels of experience.

Clinical Competence↗
PubMed2003

Robot-assisted laparoscopic colorectal surgery.

Colorectal surgery can be difficult at open and laparoscopic surgery. This is particularly the case for rectal surgery deep in the pelvis. In obese males distal rectal dissection can be challenging because of instrument and visual limitations. Robot-assisted laparoscopic colorectal operations do not differ significantly from the standard laparoscopic approach but it has certainly been shown that it is feasible to perform the same operation using robotic assistance for the dissection. This allows the surgeon to benefit from vastly enhanced vision and dexterity, which may ultimately translate into benefit for the patient in terms of reduced operating time, and better preservation of pelvic nerves and other structures.

Colonic Diseases↗
PubMed2003

Multiple Objective Measures of Skill (MOMS): a new approach to the assessment of technical ability in surgical trainees.

OBJECTIVE: The assessment of surgical technical skills has become an important topic in recent years. This study presents the validation of a 6-task skills examination for junior surgical trainees (at the level of the Membership of the Royal College of Surgeons). SUMMARY BACKGROUND DATA: Six tasks were evaluated in a project that also examined the feasibility of this method of assessment. The tasks were knowledge of sutures and instruments; knowledge of surgical devices; knot formation; skin-pad suturing, closure of an enterotomy; excision of a skin lesion; and laparoscopic manipulation. Comparisons were made between a group of junior trainees (n = 13), and a group of seniors (n = 8). RESULTS: Each of the 6 tasks was able to be used to discriminate between the 2 groups. In all, there were 19 primary analyses across the 6 tasks, and 17 of these showed significant differences between the groups (P values ranging from 0.037 to < 0.001). There was generally a strong correlation between the analyses, and when a mean rank was calculated, the difference between groups was significant (P = 0.005 on Mann-Whitney U test; mean ranks 13.9 and 6.3 [of 21], for juniors and seniors respectively). Reliability of the 6-task assessment was very good at 0.70 (Cronbach's Alpha). CONCLUSIONS: A skills examination is a feasible and effective method of assessing the technical ability of basic surgical trainees.

Computer Graphics↗
PubMed2002

Resection of soft tissue sarcomas with intra-operative magnetic resonance guidance.

PURPOSE: To report on a preliminary series of magnetic resonance (MR)-guided sarcoma resections. MATERIALS AND METHODS: Three patients with the skin sarcoma dermatofibrosarcoma protuberans underwent MR-guided resection. RESULTS: The extent of the tumor at MR imaging was greater in each case than suggested by clinical examination. Adequate resection margins were planned using short Tau inversion recovery (STIR) sequences and intra-operative imaging was used to confirm complete tumor excision. Histological examination confirmed clear surgical margins of at least 1 cm in each case. CONCLUSION: We believe this technique may reduce the incidence of specimen margins positive for tumor following resection, and consequently reduce the need for further excisional surgery.

Adult↗
PubMed2002

The relationship between motion analysis and surgical technical assessments.

BACKGROUND: Recent attempts to gain a more objective measure of surgical technical skill include the use of structured checklists and motion analysis of surgeons' hand movements. We aim to show whether a correlation exists between these two methods of assessment. METHODS: Fifty subjects were recruited from four experience groups in general surgery, ranging from basic surgical trainees to consultants and were assessed performing a standardized laboratory-based task. Motion analysis using the Imperial College Surgical Assessment Device (ICSAD), which measures hand movements and time taken, and the Objective Structured Assessment of Technical Skill (OSATS) technique were used to measure skill. RESULTS: Number of movements made, time taken, and global rating score discriminated between performance and experience group (Kruskal-Wallis, P <0.001, P <0.01, P <0.001, respectively). There was a significant correlation between movements made and global rating score (Spearman coefficient 0.53, P <0.01). Checklist scoring was not an accurate predictor of experience. CONCLUSIONS: There is a strong correlation between hand motion analysis using ICSAD and OSATS global rating assessments in this model.

Clinical Competence↗
PubMed2002

An innovative model for teaching and learning clinical procedures.

CONTEXT: Performing a clinical procedure requires the integration of technical clinical skills with effective communication skills. However, these skills are often taught separately. OBJECTIVES: To explore the feasibility and benefits of a new conceptual model for integrated skills teaching. : Design A qualitative observation and interview-based study of undergraduate medical students. METHODOLOGY: Medical students performed technical and communication skills in realistic clinical scenarios (urinary catherization and wound closure), using latex models connected to simulated patients (SPs). Procedures were observed, videorecorded and assessed by tutors from an adjoining room. Students received immediate feedback from tutors and SPs, before engaging in a process of individual feedback through private review of their videotapes. Group interviews explored the response of students, SPs and tutors. Data were analysed using standard qualitative techniques. SUBJECTS: Fifty-one undergraduate students were recruited from the Faculty of Medicine, Imperial College, London. RESULTS: The scenarios provided a realistic simulation of two common clinical situations and proved feasible in terms of time, facilities and resources within this institution. Students found the opportunity to integrate communication and technical skills valuable, challenging and an appropriate learning experience. Immediate feedback was especially highly valued. Some students found difficulty integrating technical and communications skills, but benefited from conducting two procedures in the same session. CONCLUSION: The integrated model was feasible and was perceived to be valuable. Benefits include the opportunity to integrate, within a safe environment, skills which are often taught separately. Promoting reflective practice may enable the successful transfer of these integrated skills to other procedures.

Clinical Competence↗