Visual cues of soft-tissue behaviour in minimal-invasive and robotic surgery.

Minimal-invasive surgery (MIS) and robotic surgery (RS) offer multiple advantages over open surgery (Vajsbaher et al. in Cogn Syst Res 64:08, 2020). However, the lack of haptic feedback is still a limitation. Surgeons learn to adapt to this lack of haptic feedback using visual cues to make judgements about tissue deformation. Experienced robotic surgeons use the visual interpretation of tissue as a surrogate for tactile feedback. The aim of this review is to identify the visual cues that are consciously or unconsciously used by expert surgeons to manipulate soft tissue safely during Minimally Invasive Surgery (MIS) and Robotic Surgery (RS). We have conducted a comprehensive literature review with papers on visual cue identification and their application in education, as well as skill assessment and surgeon performance measurement with respect to visual feedback. To visualise our results, we provide an overview of the state-of-the-art in the form of a matrix across identified research features, where papers are clustered and grouped in a comparative way. The clustering of the papers showed explicitly that state-of-the-art research does not in particular study the direct effects of visual cues in relation to the manipulation of the tissue and training for that purpose, but is more concentrated on tissue identification. We identified a gap in the literature about the use of visual cues for educational design solutions, that aid the training of soft-tissue manipulation in MIS and in RS. There appears to be a need RS education to make visual cue identification more accessible and set it in the context of manipulation tasks.