Preliminary Evaluation of the Pattern Cutting and the Ligating Loop Virtual Laparoscopic Trainers

Amine Chellali, PhD, Woojin Ahn, PhD, Ganesh Sankaranarayanan, PhD, Jeff Flinn, MS, Steven D Schwaitzberg, MD, Daniel B Jones, MD, Suvranu De, ScD, Caroline G. L Cao, PhD. Cambridge Health Alliance, Harvard Medical School, Rensselaer Polytechnic Institute, Wright State University, Beth Israel Deaconess Medical Center.

INTRODUCTION: The Fundamentals of Laparoscopic Surgery (FLS) trainer is currently the standard for evaluating laparoscopic skills. However, it lacks objective and automated assessments of performance. The Virtual Basic Laparoscopic Skill Trainer (VBLaST©) is the virtual version of the FLS trainer which allows automatic and real time performance assessment of laparoscopic skills without the need of a human proctor. In this study, the VBLaST© pattern cutting (VBLaST-PC©) and ligating loop (VBLaST-LL©) trainers were evaluated as part of a validation study. We hypothesized that performance would be similar on the FLS and VBLaST© trainers, and that subjects with more experience would perform better than those with less experience on both trainers.

METHODS: A total of fifty five subjects with varying surgical experience (33 for the pattern cutting task and 22 for the ligating loop) were recruited at the learning center during the 2013 SAGES annual meeting. For each task, subjects were divided into two groups: experts (PGY 5, surgical fellows and practicing laparoscopic surgeons) and novices (PGY 1-4). The subjects were asked to perform the pattern cutting task or the ligating loop task on both the FLS and the VBLaST© trainers (Figure 1). Their performance scores for each trainer, based on the time to complete the task and error, were calculated and compared.

Figure 1: (1) the pattern cutting trainers, (2) the ligating loop trainers (left: VBLaST©, right: FLS trainer)

RESULTS:

Pattern Cutting task
The Mann Whitney U-test showed that the FLS and the VBLaST-PC scores (Table 1) were significantly higher in the expert group than in the novice group (U=39, Z=3.49, p=0.000; U=68, Z=2.45, p=0.01, respectively). Moreover, the Wilcoxon signed rank sum test showed no significant difference between the FLS and the VBLaST-PC scores (Z=1.94, p>0.05).

Ligating loop task
The Mann Whitney U-test showed that the FLS and the VBLaST-LL scores (Table 1) were significantly higher in the expert group than in the novice group (U=27.5, Z=2.16, p=0.03; U=27.5, Z=2.13, p=0.03). Moreover, the Wilcoxon signed rank sum test showed no significant differences between the FLS and the VBLaST-LL scores (Z=0.21, p>0.05).

Table 1: compraison of FLS and VBLaST scores for novice and expert groups

CONCLUSION: In this preliminary study, the VBLaST© trainer was compared to the FLS box trainer to validate the pattern cutting and the ligating loop tasks. Results showed that the subject’s performance on the VBLaST© trainer was similar to the FLS performance for both tasks. Moreover, the VBLaST-PC VBLaST-LL permitted discrimination between the novice and expert groups, providing supporting evidence of concurrent validity. Further improvements of the VBLaST© system will likely be needed to further studies of validation. Once validated as a training system for laparoscopic surgical skills, the VBLaST system is expected to overcome the current limitations of the FLS box trainer.

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