Augmented reality guidance for rib fracture surgery: A feasibility study

Rib fractures occur in 10% of all trauma patients. Surgical fixation of the fractured ribs is usually performed to improve the respiratory mechanics and reduce pain. Rib fractures can be observed in x-ray and CT scans allowing for better surgical planning. However, translating the surgical plan to the operating table through mental mapping remains a challenging task. This is due to the lack of visual and tactile feedback in identifying the fractured ribs, especially when the patient is obese or when rib fractures are subtle. Using augmented reality (AR), a preoperative plan can be intraoperatively visualized in the field of view of the surgeon, allowing for a more accurate determination of the size and location of the incision for optimum access to the fractured ribs. This study aims to evaluate the use of AR for guidance in rib fracture procedures. To that end, an AR system using the HoloLens 2 was developed to visualize surgical incisions directly overlayed on the patient. The system tracks ArUco markers and aligns the preoperative model using landmarks-based registration. To evaluate the feasibility of the system, a torso phantom with registration landmarks was 3D scanned for preoperative planning of the incision lines. A user study with 13 participants was conducted to align the preoperative torso model and delineate the visualized incisions on the physical phantom. An independent optical tracking system was then used to evaluate the accuracy of the delineated incisions compared to the planned incisions. For a total of 39 delineated incisions, a mean distance error of 3.6±1.7 mm was achieved. The study shows the potential of using AR as an alternative to the traditional palpation approach for locating rib fractures, which has an error of up to 5 cm. Further assessment of the system in clinical settings is needed to demonstrate its clinical applicability.