Navigational Augmented Reality for Robotic Drilling

Fracture fixation surgery is a complex procedure that requires precise placement and drilling of screws or plates to stabilize the broken bone. Precise drilling during surgery can be achieved by orthopedic robots, which can help achieve minimally invasive surgery in terms of preoperative planning and precise intraoperative control, ultimately reducing the surgical pressure on doctors. However, the current assistance in existing systems mainly uses 2D images, and thus, doctors need a more intuitive understanding of the surgical situation. As a technology of overlaying the virtual world on the real world, Augmented Reality (AR) can be used to provide more intuitive guidance. Therefore, this article proposes an AR-assisted robotic bone-drilling system to help improve drilling accuracy and reduce the difficulty of drilling surgery. In this system, AR overlays virtual bones on the natural human body and provides an intuitive way to place target drilling sites. The robotic arm will then be navigated to the target drilling site during the surgery, where the doctor can complete the drilling operation accurately. The proposed system was finally evaluated in terms of AR placement accuracy and drilling accuracy. The AR placement experiments were performed on a bone phantom with errors of $4.53 \pm 2.05$ mm and 5.05 ± 2.82°. Moreover, the final drilling accuracy on four pig femur heads is $4.06 \pm 2.40$ mm and 3.62 ± 2.40°.