Haptic Feedback for Control and Active Constraints in Contactless Laser Surgery: Concept, Implementation, and Evaluation.

Haptics has proven to be highly beneficial in surgical robotics, bringing enhanced safety and precision by complementing the surgeon's visual channel. However, most of the research body in this context is dedicated to applications involving traditional "cold steel" surgical instruments. This paper proposes to bring the benefits of haptics to contactless surgeries, and presents a novel method to achieve this. The specific case of robot-assisted laser microsurgery is investigated. Here, a fictitious force feedback is created through stereoscopic visualization and 3D reconstruction, allowing the surgeon to sense the surgical area haptically while controlling a non-contact surgical laser. This is shown to significantly improve system usability and the accuracy of laser incisions, especially in applications involving several passes of the laser over the same incision line. Validation of the system is performed through two series of experiments involving both naive users and expert surgeons. The obtained results demonstrate that haptics can indeed be introduced in contactless laser surgery, allowing the exploitation of active constraints and guidance techniques that significantly enhance laser control accuracy both in static and dynamic environments. Furthermore, the proposed haptic technology shows good acceptance and high usability, indicating it has great potential to positively impact real surgeries.