2012 APDS spring meetingObjective Differentiation of Force-Based Laparoscopic Skills Using a Novel Haptic Simulator
Introduction
Proficiency in laparoscopic surgery requires mastery of a complex skill set that is fundamentally different from open surgery.1 In particular, the forces experienced through laparoscopic instruments are fundamentally different from those experienced in open surgery wherein surgeons directly touch tissues with gloved hands. In laparoscopy, the forces from tissue interactions are combined with friction in the trocar as well as the pivoting of the tools causing a fulcrum effect.2, 3, 4, 5 As a result, learning to accurately interpret forces felt with tools, and apply controlled forces using them, is challenging for novice surgeons.
Several investigators have sought to analyze forces exerted by surgeons during laparoscopy.2, 6, 7 Richards and coworkers' detailed study, for example, documented force data from expert laparoscopic surgeons and novices as they performed 2 common laparoscopic procedures on an animal model.6 Analysis of in vivo force data revealed that expert surgeons and novices differed in the magnitude of forces applied with laparoscopic tools. Differences in applied forces were significant for 3 surgical skills: grasping, probing, and sweeping (shown in Fig. 1).6 Grasping was defined as applying pinch forces on tool handles to grasp and handle tissues. Probing was defined as using the laparoscopic tool to prod the tissue and perform dissection, a large part of laparoscopic procedures. Sweeping was defined as the lateral motion of the tool as tissues and organs are moved or cleared to reach the surgical site of interest. On all 3 skills, expert surgeons applied precise and controlled forces demonstrating superior haptic skills.6, 8, 9
Training the force-based surgical skills of novice surgeons and residents is especially important because a majority of surgical errors during laparoscopy are caused because of improper application of forces.10 However, no known validated training methods or curricula address this aspect of surgical skills training. Currently, residents learn haptic skills while practicing on animal models in the operating room while receiving verbal feedback from experts. Though operating room training cannot be completely eliminated or replaced, we believe that it can be optimized by initial training on simulators (Fig. 2).
Current laparoscopic skills training methods are depicted in Figure 2, including both simulators and operating room-based training. The current standard for basic laparoscopic skills training is the Fundamentals of Laparoscopic Surgery (FLS) curriculum and trainer which includes 5 basic hand-eye coordination and suturing tasks.11 This simulator-based curriculum has been demonstrated to effectively develop basic laparoscopic skills that transfer to the operating room (predictive validity).12, 13, 14, 15 Simulator-based training can thus enable better-prepared surgeons entering the operating room. Further, there are other inherent advantages to using simulators that include objective assessment of skill and the ability to practice in a penalty-free environment.
The FLS curriculum, however, does not currently include training for force-based laparoscopic skills. Consequently, there is a need for developing haptic skills simulators that will shift the learning of initial force-based skills away from the operating room. This would enable residents entering the operating room to be better equipped with a wider skill set and be better prepared to benefit from operating room training.
What is remarkable about the success of the FLS skills training curriculum is that the program does not seek to realistically recreate the surgical environment; rather, the 5 training tasks recreate the salient or core hand-eye coordination skills that are basic to perform laparoscopic surgery. Similarly, it is hypothesized that there is also a set of salient haptic skills needed for skilled laparoscopy.
Based on previous studies,6, 16, 17, 18 we propose 3 salient haptic laparoscopic skills that require skilled application of forces: grasping, probing, and sweeping. A novel simulator for rendering these 3 force skills was developed and tested previously.19 As a first step toward validating the haptic simulator, this study specifically addresses its construct validity, i.e., can the simulator differentiate between expert and novice haptic skill? The overall hypothesis of this study is that surgeons will apply significantly different force magnitudes than those of novices in all 3 haptic skills. The outcomes of this study will directly contribute toward the development of haptic simulators for initial, simulator-based skills training.
Section snippets
Participants
A total of 34 participants enrolled in the study and were divided into two groups: novices, with no previous surgical experience, and surgeons, with some level of surgical experience (including upper level residents and attendings). All participants provided informed consent. The study was approved by the Clemson University Institutional Review Board. Before beginning the experiment, participants completed a brief questionnaire with demographic information and video gaming history, because
Results
To assess differences in force application between novices and surgeons, regression models were computed with produced score as a function of actual score. Models were computed for each participant, and all coefficients were averaged to obtain overall averages for surgeon and novice groups for each task. Independent samples t tests were then used to compare the performance of surgeons with that of novices. Numerical values of coefficients with corresponding statistical significance values are
Discussion
In this study, novices applied greater force magnitudes than surgeons on the haptic simulator for all 3 tasks (grasping, probing, and sweeping) at particular force ranges. Thus, using the force-based metric on the simulator (score), haptic skill of surgeons can be objectively differentiated from that of novices. To our knowledge, this is the first study to quantify the difference in haptic skill between novices and surgeons on a haptic laparoscopic simulator using a force-based metric.
Previous
Conclusions
In this work, the ability of a novel haptic simulator to objectively measure force skill of surgeons and novices was examined. Results establish the initial construct validity of the simulator by objectively differentiating the haptic skill of surgeons from that of novices. This study may be a first step towards the validation of haptic simulators for initial force-based surgical skills training, enabling the optimization of expensive operating room training time. The difference in performance
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Objective Assessment of Laparoscopic Force and Psychomotor Skills in a Novel Virtual Reality-Based Haptic Simulator
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2019, Journal of Surgical EducationCitation Excerpt :Besides real-time feedback, post-test feedback of force parameters has also been found to elicit a significant improvement of the interaction forces during the knot-tying face of suturing, whereas the effect of training without any feedback did not improve force use.12 A simulator equipped with visual force feedback significantly improves precision and accuracy of force application by combining real-time visual feedback after practicing specifically designed tasks.10,24,83 Instead of visual feedback, Wottawa et al. have investigated the effect of enhanced tactile feedback.
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