Does a 3D Image Improve Laparoscopic Motor Skills?

AIM: To quantitatively determine whether a three-dimensional (3D) image improves laparoscopic performance compared with a two-dimensional (2D) image. METHOD: This is a prospective study with two groups of participants: novices (5) and experts (5). Individuals within each group undertook a validated laparoscopic task on a box simulator, alternating between 2D and a 3D laparoscopic image until they had repeated the task five times with each imaging modality. A dedicated motion capture camera was used to determine the time taken to complete the task (seconds) and instrument distance traveled (meters). RESULTS: Among the experts, the mean time taken to perform the task on the 3D image was significantly quicker than on the 2D image, 40.2 seconds versus 51.2 seconds, P < .0001. Among the novices, the mean task time again was significantly quicker on the 3D image, 56.4 seconds versus 82.7 seconds, P < .0001. There was no significant difference in the mean time it took a novice to perform the task using a 3D camera compared with an expert on a 2D camera, 56.4 seconds versus 51.3 seconds, P = .3341. CONCLUSION: The use of a 3D image confers a significant performance advantage over a 2D camera in quantitatively measured laparoscopic skills for both experts and novices. The use of a 3D image appears to improve a novice's performance to the extent that it is not statistically different from an expert using a 2D image.

The LEAP™ Gesture Interface Device and Take-Home Laparoscopic Simulators: A Study of Construct and Concurrent Validity.

AIM: To assess the potential of the LEAP™ infrared motion tracking device to map laparoscopic instrument movement in a simulated environment. Simulator training is optimized when augmented by objective performance feedback. We explore the potential LEAP has to provide this in a way compatible with affordable take-home simulators. METHOD: LEAP and the previously validated InsTrac visual tracking tool mapped expert and novice performances of a standardized simulated laparoscopic task. Ability to distinguish between the 2 groups (construct validity) and correlation between techniques (concurrent validity) were the primary outcome measures. RESULTS: Forty-three expert and 38 novice performances demonstrated significant differences in LEAP-derived metrics for instrument path distance (P < .001), speed (P = .002), acceleration (P < .001), motion smoothness (P < .001), and distance between the instruments (P = .019). Only instrument path distance demonstrated a correlation between LEAP and InsTrac tracking methods (novices: r = .663, P < .001; experts: r = .536, P < .001). Consistency of LEAP tracking was poor (average % time hands not tracked: 31.9%). CONCLUSION: The LEAP motion device is able to track the movement of hands using instruments in a laparoscopic box simulator. Construct validity is demonstrated by its ability to distinguish novice from expert performances. Only time and instrument path distance demonstrated concurrent validity with an existing tracking method however. A number of limitations to the tracking method used by LEAP have been identified. These need to be addressed before it can be considered an alternative to visual tracking for the delivery of objective performance metrics in take-home laparoscopic simulators.

Virtual reality versus box laparoscopic simulators in trainee selection and aptitude testing.

BACKGROUND: The purpose of this study was to compare the validity of high-fidelity and low-fidelity simulators in a selection center environment, using measures of construct and concurrent validity. METHODS: A total of 46 novice and expert participants were tested on both the low-fidelity Fundamentals of Laparoscopic Surgery (FLS) box trainer and the high fidelity, Lapsim, virtual reality laparoscopic simulator. Outcome scores and performance metrics where recorded. RESULTS: Experts performed better than novices on the FLS (median 71% vs. 51%; P<0.0001) but not the Lapsim (59.1% vs. 57.1%; P = 0.41). No correlation was found between overall Lapsim metrics and FLS outcome scores (correlation = -0.024; P = 0.874). Although most novice participants performed within a narrow window on the FLS simulator, a few high-performing and low-performing outliers where identified. CONCLUSIONS: In a selection center scenario, testing with low-fidelity platforms appears to demonstrate greater validity. Outliers can be identified using low-fidelity simulators.

Accessible laparoscopic instrument tracking ("InsTrac"): construct validity in a take-home box simulator.

INTRODUCTION: Objective performance feedback has potential to maximize the training benefit of laparoscopic simulators. Instrument movement metrics are, however, currently the preserve of complex and expensive systems. We aimed to develop and validate affordable, user-ready software that provides objective feedback by tracking instrument movement in a "take-home" laparoscopic simulator. MATERIALS AND METHODS: Computer-vision processing tracks the movement of colored bands placed around the distal instrument shafts. The position of each instrument is logged from the simulator camera feed and movement metrics calculated in real time. Ten novices (junior doctors) and 13 general surgery trainees (StR) (training years 3-7) performed a standardized task (threading string through hoops) on the eoSim (eoSurgical™ Ltd., Edinburgh, Scotland, United Kingdom) take-home laparoscopic simulator. Statistical analysis was performed using unpaired t tests with Welch's correction. RESULTS: The software was able to track the instrument tips reliably and effectively. Significant differences between the two groups were observed in time to complete task (StR versus novice, 2 minutes 33 seconds versus 9 minutes 53 seconds; P=.01), total distance traveled by instruments (3.29 m versus 11.38 m, respectively; P=.01), average instrument motion smoothness (0.15 mm/second(3) versus 0.06 mm/second(3), respectively; P<.01), and handedness (mean difference between dominant and nondominant hand) (0.55 m versus 2.43 m, respectively; P=.03). There was no significant difference seen in the distance between instrument tips, acceleration, speed of instruments, or time off-screen. CONCLUSIONS: We have developed software that brings objective performance feedback to the portable laparoscopic box simulator. Construct validity has been demonstrated. Removing the need for additional motion-tracking hardware makes it affordable and accessible. It is user-ready and has the potential to enhance the training benefit of portable simulators both in the workplace and at home.

Construct, concurrent, and content validity of the eoSim laparoscopic simulator.

BACKGROUND: The purpose of this study was to validate the eoSim box laparoscopic simulator using measures of construct, concurrent, and content validity. SUBJECTS AND METHODS: Forty-seven novice and expert participants were tested on both the Fundamentals of Laparoscopic Surgery (FLS™; Society of American Gastrointestinal and Endoscopic Surgeons, Los Angles, CA) and eoSim (eoSurgical™, Edinburgh, Scotland, United Kingdom) laparoscopic simulators, using established scoring mechanisms. Three skill areas were examined: object transfer, precision cutting, and intracorporeal suturing. A questionnaire was also completed. RESULTS: Experts performed significantly better on the eoSim than novices, with a median score of 51.1% versus 14.8% (P<.0001), showing construct validity. There was a high correlation between performance on the validated FLS simulator and the eoSim (0.78; P<.0001), demonstrating concurrent validity. Feedback from participants indicated an agreement that the eoSim was a useful training tool providing content validity. CONCLUSIONS: The eoSim demonstrates validity as a model for laparoscopic simulation. It is hoped that its decreased cost relative to other simulators will encourage increased uptake by trainees and institutions.

Thymectomy for inducing remission in juvenile myasthenia gravis.

PURPOSE: The aim of this study was to determine the efficacy of thymectomy to induce remission in juvenile myasthenia gravis. METHODS: A retrospective review of all patients undergoing a thymectomy for the treatment of juvenile myasthenia gravis was performed at a single tertiary referral centre between 1997 and 2009 (N = 8). All cases were moderate to severe cases (Osserman stage ≥ 2a). All operations were open. Median follow-up was 18 months (range 1-77). Postoperative progress was assessed using the De Filippi classification of remission. MAIN RESULTS: Only two minor complications were reported. Mean operative time was 120 min (range 80-290 min). Mean postoperative stay was 17 days (range 3-52 days). Remission was observed in 5 of 8 patients (62%) at last known follow up. CONCLUSIONS: Spontaneous remission rates for myasthenia gravis are quoted to be between 20 and 29% while remission rates following thymectomy are 29-68% at 3 years. Although not all of our patients have had 3 years of follow up-the remission rate of 62% demonstrated by this study is encouraging. If reproducible over a larger series this provides evidence of the efficacy of thymectomy for treating juvenile myasthenia gravis in selected patients.