Effect of Auto-Erased Sketch Cue in Multiuser Surgical Planning Virtual Reality with Various Visual Communication Cues

Many researchers have introduced Virtual Reality (VR) systems for various medical applications, such as training, education, and collaboration. In this research, we explore the effect of using 3-second sketch communication cue in a collaborative VR system for two surgeons planning surgery, when a head-gaze pointer and hand-gesture are available as the baseline cues. We defined five steps of surgical planning for a liver cancer, based on the proposal from surgeons, and conducted a user study with the task including the five steps. The results demonstrated that the 3-second sketch cue increased the level of usability and message understanding between two collaborators, and decreased the required task load. Additionally, we propose six design principles for the interface of a surgical planning VR system. First, a 3D reconstructed body model should be supported based on real-world data, such as CT and MRI images. Second, the cross-sectional view at any angle and position should be supported for examining inside the body and organs. Third, visual communication cues, such as sketches, pointers, and hand gestures, are crucial for communication. Fourth, the erasing sketch should occur when the next sketch starts being drawn. Fifth, the system should support permanent annotations, especially attached to the 3D body, together with the volatile visual communication cues, such as hand gesture, erased sketch, and head-gaze pointer. Sixth, when both collaborators focus on the same object or area, the system should control the transparency of the hand gestures and head-gaze pointers to mitigate the effect of occlusions.