A research team reports on June 17 that a new system combining robotics and augmented reality has improved the accuracy of complex jaw surgery. The system, called RAMRS, integrates preoperative planning, robot-assisted osteotomy, and augmented reality-guided reconstruction into a single workflow.
The first module uses an optical tracking system and a collaborative robotic arm to guide the bone saw during osteotomy. A hand-eye calibration procedure determines the exact pose of the robot's end-effector relative to a tracking marker. During surgery, the surgeon traces the bone surface with an optical probe; data is registered to preoperative CT scans using an algorithm. The robotic arm then positions a slotted jig at the planned osteotomy plane, constraining the saw blade for precise angles and depths while compensating for patient movement.
"Our system covers the whole chain – from preoperative planning to osteotomy and finally to segment positioning and fixation – within a single, integrated framework," explains Professor Jian Yang, co-corresponding author. RAMRS consists of two modules. "This gives us angular control without needing an invasive custom guide," says Professor Jingfan Fan.
The second module addresses fibular segment alignment using augmented reality (AR). A QR marker is attached to the mandible but can be inaccurately picked due to hand tremor or deformation. To address this, researchers developed a rotating-calipers-based compensation method that reduces corner displacement by over 25% compared with conventional methods. "RCC reduces corner displacement by over 25% compared to conventional least-squares or constrained optimization," notes Dr. Long Shao. After refinement, AR overlays show surgeons where each fibular segment should be placed in real time.
RAMRS was evaluated on anatomical specimens and cadaver models mimicking clinical conditions. For fibula osteotomy, it achieved mean angular errors of 3.19° (SD 1.39°) and centroid-distance errors of 1.28 mm (SD 0.59 mm), outperforming previous methods in accuracy metrics for both fibula and mandible procedures.
Authors acknowledge challenges such as intraoperative blood contamination affecting marker tracking but plan further improvements, including robust image-enhancement algorithms and distance-warning mechanisms for vital structures protection in future studies. "Our vision is a seamless, 'see-and-cut, see-and-place' workflow where the robot handles the geometrically demanding osteotomy and AR provides real-time visual guidance for reconstruction," concludes Professor Yang.
