Suitability of a Tool-Speed-Dependent Force Model for VR-Based Soft-Tissue Dissection

Haptics: Science, Technology, and Applications. June 6th, 2018. DOI: 10.1007/978-3-319-93399-3_40.

Fernando Trejo, Yaoping Hu


Models of tool-tissue interaction forces find a potential application in Virtual Reality (VR) based simulators for surgical training. What remains unclear is the effect of such force models on user performance of surgical tasks with different tool speeds. Since soft-tissue dissection accounts for about 35% of surgical time, we herein conducted a preliminary study on user performance of the 1 degree-of-freedom dissection under an analytic force model for various tool speeds. Derived from empirical force-displacement data, the model had averagely a computation time of 2.5 µs to ensure force rendering via a haptic device. On a VR-based simulator featuring the force model, the user’s hand holding a virtual scalpel via the haptic device executed the dissection at the tool speed of 0.10, 1.27, or 2.54 cm/s. User hand movements were recorded by the simulator to compute objective performance metrics of tracing accuracy, speed accuracy, motion quality and damage reduction. User perceived workload was measured using NASA-TLX. One-way ANOVA analyses revealed significantly lower user performance for the tool speed of 0.10 cm/s, compared to both higher speeds. Nonetheless, there were no differences in perceived workload among these speeds. Agreeing with the convention that a low tool speed demands refined hand movements in the dissection, these findings validate the suitability of the force model for VR-based soft-tissue dissection at various tool speeds.