Construct and face validity of MIST-VR, Endotower, and CELTS

BACKGROUND: Video trainers may best offer visually realistic laparoscopic simulation, whereas virtual reality (VR) modules may best provide multidimensional objective measures of performance. This study compares the construct and face validity of three different laparoscopic simulators. METHODS: Subjects were voluntarily enrolled at the Learning Center during the 2004 SAGES annual meeting. Each subject completed two repetitions of a single task on each of three simulators, MIST-VR, Endotower, and CELTS; performance scores were automatically generated and recorded. Scores of individuals with various levels of experience were compared to determine construct validity for each simulator. Experience was defined according to four parameters: (a) PGY level, (b) fellowship training, (c) basic laparoscopic cases, and (d) advanced laparoscopic cases. Subjects rated each simulator regarding six face validity (realism of simulation) parameters using a 10-point Likert scale (10 = best rating) and participant scores were compared to previously established expert scores (proficiency goals for training). RESULTS: Ninety-one attendees completed the study. Construct validity was demonstrated for all three simulators; significant differences in scores were detected according to one parameter for MIST-VR, two parameters for Endotower, and all four parameters for CELTS. Face validity was rated as good to excellent for all three simulators (7.0 +/- 0.3 for MIST-VR, 7.9 +/- 0.3 for Endotower [p < 0.001 vs MIST-VR], and 8.7 +/- 0.1 for CELTS [p = 0.001 vs MIST-VR, p = 0.01 vs Endotower]); 6%, 0%, and 36% of "expert" participants obtained expert scores on MIST-VR, Endotower, and CELTS, respectively. CONCLUSIONS: All three simulators demonstrated significant construct and reasonable face validity. Although virtual reality holds great promise to expand the scope of laparoscopic simulation, current interfaces may limit their utility for assessment. Computer-enhanced video trainers may offer an improved interface while incorporating useful multidimensional metrics. Further work is needed to establish standards for appropriate skills assessment methods and performance levels using simulators.     

Validation of a new basic virtual reality simulator for training of basic endoscopic skills

BACKGROUND: The aim of this study was to establish content, face, concurrent, and the first step of construct validity of a new simulator, the SIMENDO, in order to determine its usefulness for training basic endoscopic skills. METHODS: The validation started with an explanation of the goals, content, and features of the simulator (content validity). Then, participants from eight different medical centers consisting of experts (> or =100 laparoscopic procedures performed) and surgical trainees (<100) were informed of the goals and received a "hands-on tour" of the virtual reality (VR) trainer. Subsequently, they were asked to answer 28 structured questions about the simulator (face validity). Ratings were scored on a scale from 1 (very bad/useless) to 5 (excellent/very useful). Additional comments could be given as well. Furthermore, two experiments were conducted. In experiment 1, aimed at establishing concurrent validity, the training effect of a single-handed hand-eye coordination task in the simulator was compared with a similar task in a conventional box trainer and with the performance of a control group that received no training. In experiment 2 (first step of construct validity), the total score of task time, collisions, and path length of three consecutive runs in the simulator was compared between experts (>100 endoscopic procedures) and novices (no experience). RESULTS: A total of 75 participants (36 expert surgeons and 39 surgical trainees) filled out the questionnaire. Usefulness of tasks, features, and movement realism were scored between a mean value of 3.3 for depth perception and 4.3 for appreciation of training with the instrument. There were no significant differences between the mean values of the scores given by the experts and surgical trainees. In response to statements, 81% considered this VR trainer generally useful for training endoscopic techniques to residents, and 83% agreed that the simulator was useful to train hand-eye coordination. In experiment 1, the training effect for the single-handed task showed no significant difference between the conventional trainer and the VR simulator (concurrent validity). In experiment 2, experts scored significantly better than novices on all parameters used (construct validity). CONCLUSION: Content, face, and concurrent validity of the SIMENDO is established. The simulator is considered useful for training eye-hand coordination for endoscopic surgery. The evaluated task could discriminate between the skills of experienced surgeons and novices, giving the first indication of construct validity.     

Randomized prospective blinded study validating acquistion of ureteroscopy skills using computer based virtual reality endourological simulator

PURPOSE: Surgical simulation has emerged in the last decade as a potential tool for aiding acquisition of technical skills, including anesthesia protocols, trauma management, cardiac catheterization and laparoscopy. We evaluate and validate the use of a computer based ureteroscopy simulator (URO Mentor, Simbionix Ltd., Lod, Israel) in the acquisition of basic ureteroscopic skills. MATERIALS AND METHODS: We assessed 20 novice trainees for the ability to perform basic ureteroscopic tasks on a computer based ureteroscopy simulator. Participants were randomized to receive individualized mentored instruction or no additional training, and subsequently underwent post-testing. Pre-training and post-training improvement in performance was assessed by objective simulator based measurements. Subjective overall performance was rated using a validated endourological global rating scale by an observer blinded to subject training status. RESULTS: Demographics and pre-test scores were similar between groups. Post-testing revealed a significant effect of training on objective and subjective measurements. Spearman rank correlation demonstrated a significant association between objective simulator based measurements and the endourological global rating scale. CONCLUSIONS: Use of a computer based ureteroscopy simulator resulted in rapid acquisition of ureteroscopic skills in trainees with no prior surgical training. Results of this study demonstrate the use of a virtual reality ureteroscopy simulator in endourological training. Correlation of simulator based measurements with a previously validated endourological global rating scale provides initial validation of the ureteroscopy simulator for the assessment of ureteroscopic skills.     

A surgical virtual reality simulator distinguishes between expert gynecologic laparoscopic surgeons and perinatologists

Background:Concern regarding the quality of surgical training in obstetrics and gynecology residency programs is focusing attention on competency based education. Because open surgical skills cannot necessarily be translated into laparoscopic skills and with minimally invasive surgery becoming standard in operative gynecology, the discrepancy in training between obstetrics and gynecology will widen. Training on surgical simulators with virtual reality may improve surgical skills. However, before incorporation into training programs for gynecology residents the validity of such instruments needs to first be established. We sought to prove the construct validity of a virtual reality laparoscopic simulator, the SurgicalSim^TM, by showing its ability to distinguish between surgeons with different laparoscopic experience.Methods:Eleven gynecologic surgeons (experts) and 11 perinatologists (controls) completed 3 tasks on the simulator, and 10 performance parameters were compared.Results:The experts performed faster, more efficiently, and with fewer errors, proving the construct validity of the SurgicalSim.Conclusions:Laparoscopic virtual reality simulators can measure relevant surgical skills and so distinguish between subjects having different skill levels. Hence, these simulators could be integrated into gynecology resident endoscopic training and utilized for objective assessment. Second, the skills required for competency in obstetrics cannot necessarily be utilized for better performance in laparoscopic gynecology.     

Assessment of construct validity of a virtual reality laparoscopy simulator

BACKGROUND: The aim of this study was to assess whether virtual reality (VR) can discriminate between the skills of novices and intermediate-level laparoscopic surgical trainees (construct validity), and whether the simulator assessment correlates with an expert's evaluation of performance. METHODS: Three hundred and seven (307) participants of the 19th-22nd Davos International Gastrointestinal Surgery Workshops performed the clip-and-cut task on the Xitact LS 500 VR simulator (Xitact S.A., Morges, Switzerland). According to their previous experience in laparoscopic surgery, participants were assigned to the basic course (BC) or the intermediate course (IC). Objective performance parameters recorded by the simulator were compared to the standardized assessment by the course instructors during laparoscopic pelvitrainer and conventional surgery exercises. RESULTS: IC participants performed significantly better on the VR simulator than BC participants for the task completion time as well as the economy of movement of the right instrument, not the left instrument. Participants with maximum scores in the pelvitrainer cholecystectomy task performed the VR trial significantly faster, compared to those who scored less. In the conventional surgery task, a significant difference between those who scored the maximum and those who scored less was found not only for task completion time, but also for economy of movement of the right instrument. CONCLUSIONS: VR simulation provides a valid assessment of psychomotor skills and some basic aspects of spatial skills in laparoscopic surgery. Furthermore, VR allows discrimination between trainees with different levels of experience in laparoscopic surgery establishing construct validity for the Xitact LS 500 clip-and-cut task. Virtual reality may become the gold standard to assess and monitor surgical skills in laparoscopic surgery.     

Virtual reality applied to procedural testing: the next era

OBJECTIVE: To establish the construct validity of a virtual reality-based upper gastrointestinal endoscopy simulator as a tool for the skills training of residents. SUMMARY BACKGROUND DATA: Previous studies have demonstrated the relevance of virtual reality training as an adjunct to traditional operating room learning for residents. The use of specific task trainers, which have the ability to objectively analyze and track user performance, has been shown to demonstrate improvements in performance over time. Using this off-line technology can lessen the financial and ethical concerns of using operative time to teach basic skills. METHODS: Thirty-five residents and fellows from General Surgery and Gastrointestinal Medicine were recruited for this study. Their performance on virtual reality upper endoscopy tasks was analyzed by computer. Assessments were made on parameters such as time needed to finish the examination, completeness of the examination, and number of wall collisions. Subjective experiences were queried through questionnaires. Users were grouped according to their prior level of experience performing endoscopy. RESULTS: Construct validation of this simulator was demonstrated. Performance on visualization and biopsy tasks varied directly with the subjects' prior experience level. Subjective responses indicated that novice and intermediate users felt the simulation to be a useful experience, and that they would use the equipment in their off time if it were available. CONCLUSIONS: Virtual reality simulation may be a useful adjunct to traditional operating room experiences. Construct validity testing demonstrates the efficacy of this device. Similar objective methods of skills evaluation may be useful as part of a residency skills curriculum and as a means of procedural skills testing.     

Construct validity of the LapSim: Can the LapSim virtual reality simulator distinguish between novices and experts?

Background Virtual reality simulators may be invaluable in training and assessing future endoscopic surgeons. The purpose of this study was to investigate if the results of a training session reflect the actual skill of the trainee who is being assessed and thereby establish construct validity for the LapSim virtual reality simulator (Surgical Science Ltd., Gothenburg, Sweden). Methods Forty-eight subjects were assigned to one of three groups: 16 novices (0 endoscopic procedures), 16 surgical residents in training (>10 but <100 endoscopic procedures), and 16 experienced endoscopic surgeons (>100 endoscopic procedures). Performance was measured by a relative scoring system that combines single parameters measured by the computer. Results The higher the level of endoscopic experience of a participant, the higher the score. Experienced surgeons and surgical residents in training showed statistically significant higher scores than novices for both overall score and efficiency, speed, and precision parameters. Conclusions Our results show that performance of the various tasks on the simulator corresponds to the respective level of endoscopic experience in our research population. This study demonstrates construct validity for the LapSim virtual reality simulator. It thus measures relevant skills and can be integrated in an endoscopic training and assessment program.     

SE16VIRTUAL REALITY LAPAROSCOPIC TRAINING IN AUSTRALIA

Opinions on the role of virtual reality simulation in surgical training are diverse and usually not evidence‐based. Several adequately powered, randomised and blinded studies have demonstrated an improvement in the operative performance of those who have undergone virtual reality training. Nonetheless there remains reluctance by the medical profession to incorporate simulation into training. This seems to be based on three misconceptions.

• 1 Simulators are expensive
• 2 It is difficult to incorporate them into an already overcrowded curriculum
• 3 The transfer of skill to the real world has not been demonstrated to reduce risk or improve patient outcomes.

We report on our attempts to assess the feasibility of establishing virtual training for local trainees and to assess its outcome on operative performance. 16 Basic surgical trainees were randomised into control and training groups. All underwent baseline testing of their psychomotor ability before the training group were allowed 24 hour access to a LapSim virtual reality simulator. It was not possible to complete this study and we will discuss the reasons for this which we believe has important implications for the future use of simulation in surgical training. 16 final year medical students were also recruited, and similarly randomised and assessed before being allowed access to the simulator. After four weeks of training, we were able to demonstrate a significant improvement in their simulated laparoscopic surgical skills when compared with the skills of local specialists. Using an animal model, we were able to demonstrate the effect of this on their operative performance.     

Virtual reality simulator training equals mechanical robotic training in improving robot-assisted basic suturing skills

Background This study aimed to investigate the effect of a virtual reality simulator on the learning of basic robotic suturing skills. Methods Two randomized groups of students underwent a controlled training program. Both groups completed an identical test before and after training. The increase in the number of stitches placed during the pretest and posttest was used as an objective measure of the training effect. To evaluate the subjective feeling of understanding and mastering, the students indicated this on a visual analog scale. Results Both groups showed a significant increase in the number of stitches placed during the posttest, and an increase in subjective feeling of understanding and mastering. The increase did not differ between the groups, indicating that the virtual reality simulator equaled the mechanical trainer in training of robotic suturing technique. Conclusions Training in basic robot-assisted suturing skills using a virtual reality simulator without additional training equaled training using a mechanical simulator.     

Construct validity testing of a laparoscopic surgery simulator (Lap Mentor®)

BACKGROUND: Before surgical simulators can be implemented for assessment of surgical training, their construct validity should be assessed. METHODS: Nine novices (NOV), nine medical students (MS), and nine residents (RES) underwent a laparoscopic skills training on the virtual reality (VR) simulator Lap Mentor. Assessment of laparoscopic skill was based on parameters measured by the computer system before and after training. RESULTS: Significant difference existed between RES and NOV at seven of nine tasks before training on the VR simulator. After the training in some tasks significant differences were observed between the experienced group (RES) and the nonexperienced groups (MS and NOV) or between medical groups (RES and MS) and nonmedical group (NOV). CONCLUSIONS: Performance parameters of the Lap-Mentor can be used to distinguish between subjects with varying laparoscopic experience.     

Use of a virtual reality, real-time, simulation model for the training of urologists in transurethral resection of the prostate

OBJECTIVE: There is a growing need to develop surgical skills outside the operating theatre. In this study we describe the development of a virtual reality training system for practising transurethral resection of the prostate (TURP). MATERIAL AND METHODS: A face validity study was performed using a questionnaire sent to 28 experienced urologists to find out the ideal characteristics of a simulated TURP. Based on the comments a simulator was constructed and a content validity study was then performed in which nine experienced urologists tested the simulator and answered a second questionnaire. After corrections to the simulator, a basic construct validity test was performed. RESULTS: We have developed a computer-based simulator based on the requirements listed by 17 urologists. It consists of a modified resectoscope connected to a haptic device and supported by a frame. The software provides a virtual view of the prostatic lumen and resectoscope tip, a haptic rendering that generates force feedback and a simulation module that computes the information from the haptic device, resectoscope fluid tap and handle and the foot pedals. The software also simulates bleeding, absorption of irrigation fluid and pressure gradients. Variables are measured and presented in a result file after each "operation". Nine experienced urologists performed a content validity study and changes were made accordingly. A basic construct validity test performed by seven inexperienced students showed a significant improvement in performance after they each performed six simulated procedures. CONCLUSION: We have developed a simulator that may be used to practise TURP and which meets most of the demands raised in a face validity study. A basic construct validity test showed improved performance after repeated practice in the simulated environment.     

Objective assessment of gynecologic laparoscopic skills using the LapSimGyn virtual reality simulator

BACKGROUND: Safe realistic training and unbiased quantitative assessment of technical skills are required for laparoscopy. Virtual reality (VR) simulators may be useful tools for training and assessing basic and advanced surgical skills and procedures. This study aimed to investigate the construct validity of the LapSimGyn VR simulator, and to determine the learning curves of gynecologists with different levels of experience. METHODS: For this study, 32 gynecologic trainees and consultants (juniors or seniors) were allocated into three groups: novices (0 advanced laparoscopic procedures), intermediate level (>20 and <60 procedures), and experts (>100 procedures). All performed 10 sets of simulations consisting of three basic skill tasks and an ectopic pregnancy program. The simulations were carried out on 3 days within a maximum period of 2 weeks. Assessment of skills was based on time, economy of movement, and error parameters measured by the simulator. RESULTS: The data showed that expert gynecologists performed significantly and consistently better than intermediate and novice gynecologists. The learning curves differed significantly between the groups, showing that experts start at a higher level and more rapidly reach the plateau of their learning curve than do intermediate and novice groups of surgeons. CONCLUSION: The LapSimGyn VR simulator package demonstrates construct validity on both the basic skills module and the procedural gynecologic module for ectopic pregnancy. Learning curves can be obtained, but to reach the maximum performance for the more complex tasks, 10 repetitions do not seem sufficient at the given task level and settings. LapSimGyn also seems to be flexible and widely accepted by the users.     

Face,content and construct validation of the first virtual reality laparoscopic nephrectomy simulator

Study Type – Therapy (case series)
Level of Evidence 4

OBJECTIVE

To evaluate the face, content and construct validity, and to identify whether participants improved with practice, for the Procedicus MIST Nephrectomy? simulator (Mentice, Gothenburg, Sweden), which incorporates force feedback and can record numerous performance measures (metrics) during the simulation, and which is the first virtual reality simulator for laparoscopic nephrectomy.

SUBJECTS AND METHODS

Eight expert urological laparoscopic surgeons, 10 novices and 10 trainee urologists completed at least one simulated retroperitoneal radical nephrectomy. They completed a structured questionnaire to assess face and content validity; the performance of experts and novices were then compared to evaluate construct validity.

RESULTS

Face validity was established by the experts who all felt the simulator was a good training tool. Content validity was established by the experts who rated all aspects of the simulator as above average for realism. When performance metrics were analysed, experts completed the simulated nephrectomy significantly faster than novices, with fewer errors, less simulated haemorrhage and less tool travel, which established construct validity. After practice, both novices and trainees were able to perform the simulation faster, with fewer errors, less blood loss and less tool travel.

CONCLUSIONS

This study has established the face, content and construct validity for the Procedicus MIST Nephrectomy. The simulator can distinguish experts from novices and it has potential as a laparoscopic training tool for urology.     

Perceptual, visuospatial, and psychomotor abilities correlate with duration of training required on a virtual-reality flexible endoscopy simulator

BACKGROUND: Trainees acquire endoscopic skills at different rates. Fundamental abilities testing could predict the amount of training required to reach a performance goal on a virtual-reality simulator. METHODS: Eleven medical students were tested for fundamental abilities. Baseline endoscopic proficiency was evaluated with the GI Mentor II VR simulator (Simbionix, USA, Cleveland, OH). Subjects trained on the simulator with a defined performance goal. Subjects who achieved the goal were then reassessed. RESULTS: All subjects completed at least 10 trials or reached the performance goal. The <10 trial group (n=6) tested better for all fundamental abilities and baseline endoscopic performance than the >10 trial group (n=5). The number of trials required to reach the performance goal correlated significantly with both perceptual (r=.92, P=0.001) and visuospatial ability (r=.76, P=.03). Multiple regression showed strong correlation of all three abilities with duration of training (r=.95, P=.015). CONCLUSIONS: Most of the variability in acquisition of endoscopic skills can be accounted for by differences in fundamental abilities of trainees. Testing of fundamental abilities could help identify trainees who will require additional training to achieve desired performance objectives.     

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.     

Construct validation of a novel hybrid surgical simulator

Background Simulated minimal access surgery has improved recently as both a learning and assessment tool. The construct validation of a novel simulator, ProMis, is described for use by residents in training. Methods ProMis is a surgical simulator that can design tasks in both virtual and actual reality. A pilot group of surgical residents ranging from novice to expert completed three standardized tasks: orientation, dissection, and basic suturing. The tasks were tested for construct validity. Two experienced surgeons examined the recorded tasks in a blinded fashion using an objective structured assessment of technical skills format (OSATS: task-specific checklist and global rating score) as well as metrics delivered by the simulator. Results The findings showed excellent interrater reliability (Cronbach’s α of 0.88 for the checklist and 0.93 for the global rating). The median scores in the experience groups were statistically different in both the global rating and the task-specific checklists (p < 0.05). The scores for the orientation task alone did not reach significance (p = 0.1), suggesting that modification is required before ProMis could be used in isolation as an assessment tool. Conclusions The three simulated tasks in combination are construct valid for differentiating experience levels among surgeons in training. This hybrid simulator has potential added benefits of marrying the virtual with actual, and of combining simple box traits and advanced virtual reality simulation.     

Development of a structured virtual reality curriculum for laparoscopic appendicectomy

BackgroundLaparoscopic appendicectomy (LA) is a common surgical emergency procedure mainly performed by trainees. The aim was to develop a step-wise structured virtual reality (VR) curriculum for LA to allow junior surgeons to hone their skills in a safe and controlled environment.MethodsA prospective randomized study was designed using a high-fidelity VR simulator. Thirty-five novices and 25 experts participated in the assessment and their performances were compared to assess construct validity. Learning curve analysis was performed.ResultsFive of the psychomotor tasks and all appendicectomy tasks showed construct validity. Learning was demonstrated in the majority of construct-valid tasks. A novel goal-directed VR curriculum for LA was constructed.ConclusionsA step-wise structured VR curriculum for LA is proposed with a framework which includes computer generated metrics and supports deliberate practice, spacing intervals, human instruction/feedback and assessment. Future study should test the feasibility of its implementation and transferability of acquired skill.     

A cost-effective proficiency-based knot-tying and suturing curriculum for residency programs

BACKGROUND: The purpose of this study was to develop a structured open skills curriculum for knot-tying and suturing using expert-derived performance goals and to examine its feasibility, cost-effectiveness, and construct validity. METHODS: Using commercially available bench models, 11 standardized tasks (ranging from 2-handed knot-tying to running subcuticular closure) were developed and scored using previously validated metrics based on time and errors. Expert performance was used to establish training endpoints and to create a video tutorial. PGY 1 residents (n = 4) were enrolled in a prospective Institutional Review Board-approved pilot study that included proctored orientation and baseline testing, self-training to proficiency, and proctored post-testing (conducted over a 4-wk period). Baseline trainee scores were compared with expert scores to evaluate construct validity. RESULTS: The 11 tasks proved relatively robust, and excellent feedback was obtained from the trainees regarding educational benefit. Overall, trainees performed 144 +/- 33 repetitions over 11 +/- 2 h. Trainees achieved proficiency for 4.6% of the 11 tasks at baseline, 91% during training, and 84% at post-testing. Trainees demonstrated significant improvement from baseline to post-testing, validating skill acquisition; baseline trainee and expert performance were significantly different, confirming construct validity. Curriculum development cost $1200 and required 72 man-hours. Incremental training cost less than $12 per participant and required 8 man-hours per rotation using the video-based self-practice curriculum. In response to participant feedback, two of the 11 tasks were modified and a twelfth task was added. CONCLUSIONS: This curriculum is cost-effective, feasible within the context of residency training, educationally beneficial, and demonstrates construct validity. More widespread adoption of standardized, validated skills curricula such as this by residency programs is warranted.     

Comparison of minimally invasive surgical skills of neurosurgeons versus general surgeons: is there a difference in the first exposure to a virtual reality simulator?

OBJECTIVE: The increasing use of minimally invasive surgery, which has a longer learning curve compared to open surgery lets the necessity to develop training programs to improve endoscopic skills of trainees become ever clearer. The aim of this study was to compare the endoscopic skills of neurosurgeons versus general surgeons at first exposure to a virtual reality simulator. METHODS: 72 general surgeons who visited the 122nd Conference of the German Surgeons Society (DGCH in Munich 2005) and 35 neuroendoscopic surgeons, who visited the Third World Conference of the International Study Group of Neuroendoscopy (ISGNE in Marburg 2005) participated in this study. Each participant performed the basic module "clip application" on the virtual reality simulator (LapSim). All participants were given the same pretest instructions. Time to complete the task, error score and economy of motion were recorded. RESULTS: The general surgeons performed the clip application faster, but with more errors than neuroendoscopic surgeons. However, the difference of both parameters was not significant. Both surgeon groups have a similar score for economy of motion. CONCLUSION: Although neuroendoscopic surgeons were exposed to a foreign procedure and unfamiliar equipment, they were able to perform virtual endoscopy with similar accuracy as general surgeons, who are adapted to these endoscopic instruments and procedures and do these daily.     

Measuring and developing suturing technique with a virtual reality surgical simulator.

BACKGROUND: We have developed an interactive virtual reality (VR) surgical simulator for the training and assessment of suturing technique. The surgical simulator is comprised of surgical tools with force feedback, a 3-dimensional graphics visual display of the simulated surgical field, physics-based computer simulations of the tissues and tools, and software to measure and evaluate the trainee's performance. STUDY DESIGN: This study uses the simulator to measure and compare the skills of 8 experienced vascular surgeons versus 12 medical students when performing a virtual reality suturing task. Eight parameters of the suturing task were measured: total tissue damage, accuracy of needle puncture, peak tissue tearing force, time to complete the task, damage to the surface of the tissue, angular error in needle technique, total distance traveled by the tool tip, and a measure of overall error. Three test conditions (dominant hand, nondominant hand, and 3-dimensional needle guide) were tested. Statistical significance was defined as a univariate two-sided p value < or = 0.05. RESULTS: The surgeons' average performance was significantly better than the students' average performance for three of the measured parameters (total tissue damage, time to complete the task, and total distance traveled by the tool tip) for each of the test conditions. For the test condition most similar to surgery (using the dominant hand to suture) one additional parameter was also significantly different (the measure of overall error). The medical students showed improvements for 6 of the 7 parameters for which the users received feedback during the training process. The surgeons also had significant improvement for 4 of the 7 parameters. The students had a larger improvement than the surgeons for 6 of the parameters, but these differences were not statistically significant. CONCLUSIONS: Data indicate differences between surgeon and nonsurgeon performance and in improvement in performance with training. One possible explanation for the superior performance of the surgeons is that their suturing skills applied well to the simulated suturing task. Additional research is required to confirm or deny the similarity between actual and simulated surgical tasks and the relevance of virtual reality surgical simulation to surgical skill assessment and training.