Brian F Allen, PhD, Jaisa Olasky, MD, Hussna Wakily, Daniel B Jones, MD, MS, Suvranu De, ScD, Steven Schwaitzberg, MD. Rensselaer Polytechnic Institute, Harvard Medical School.
Objective of the technology
The Virtual Electrosurgical Skills Trainer (VEST) applies the malleable tools of virtual reality and physical simulation to create a guided, safe, interactive platform to teach the principles of electrosurgery. The aim of VEST is to complement the emerging didactic curriculum of the Fundamental Use of Surgical Energy (FUSE) program, with highly immersive, hands-on training.
Description of the technology
The VEST simulator provides true three-dimensional display of the virtual tissue and electrode. The user wears polarized glasses with small retro-reflective markers. These glasses allow the user’s eyes to be tracked over six-degrees of freedom. The simulator is then able to draw the virtual scene correctly for the user’s eye position.
A small stylus controls the virtual electrosurgical tool, with motions of the hand-held stylus reflected one-to-one to the virtual electrosurgical pencil. A small button on the stylus allows the user to activate the ESU, in a manner analogous to standard ES pencils.
Building on the results of a recent survey of members of the FUSE Task Force, as well as the physical and electrical properties of various tissues the VEST simulator aims to teach a cognitive understanding and a hands-on intuition to generate common tissue effects of monopolar electrosurgery. The interactive software guides the user to perform basic functions, including selecting a proper ESU mode (e.g., “Cut” or “Coag”), selecting an appropriate power level, choosing the proper electrode tip (e.g., needle or spatula). Performance of these basic functions leads the user through proper performance of identified common electrosurgical tasks, such as fulguration and dissection.
The electrical and thermal effects of the applied current to the tissue are physically simulated, with distinct tissue phases of unaffected, desiccated, charred and vaporized. Vaporizing tissue also emits smoke particulates.
In addition to the held stylus, a touch-screen interface (using an iPad mini) allows the user to specify electrosurgical unit (ESU) settings, such as power levels and mode. Tissue effects are simulated with these settings.
Pilot testing indicated that tactile feedback is essential for the targeted electrosurgical tasks. A passive tactile feedback system was added though a physical tissue phantom. The phantom was selected for appropriate surface friction and deformation properties and can be substituted to mimic different tissue types. The user’s stylus contacts the tissue phantom at precisely the point where the virtual electrode contacts the virtual simulated tissue surface. With this setup, tactile feedback is supported without cumbersome and expensive active haptic devices (see figure). The addition of a trocar (not shown) allows laparoscopic instruments to be simulated as well.
Conclusions/Future Directions
The VEST simulator provides a means of communicating the abstract fundamentals of electrosurgery through a compelling, hands-on experience. Computer-based simulation provides a mechanism for guided interaction, direct instruction, immediate feedback and passive information display, these factors are ideal for imparting the combination of didactic and experiential learning that is essential to electrosurgery.
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