A Small-Scaled Intraoperative 3D Visualization Navigation System for Femoral Head Repair Surgery

Osteonecrosis of the femoral head is a common disabling disease in orthopaedic field. The current repair method is positioning a localization needle with the assist of fluocsopy, which is lack of stability, efficiency, and objective evaluation criteria. This surgery has the following features: (1) The incision of minimally invasive surgery for femoral head repair is very small. (2) The anatomical marks suitable for point-registration navigation and positioning are not obvious. (3) It is not easy to fix the marking points on the femur. Thus, conventional standardized surgical navigation system is not suitable for this kind of surgery with non-standardized procedures. An assisted navigation system for femoral head repair surgery is presented in this paper, with accurate and reliable effect, small scale and convenient manipulation. First of all, point cloud selected form operation window is used to perform registration and realize the precise positioning of femoral head. Secondly, a pose estimation algorithm based on 3D-3D point pairs is proposed and realized the real-time pose tracking of the needle. Finally, the real-time display of the CT model of the femoral head and the relative position of the needle is realized through the mixed reality technology, and guide the surgeons to accurately insert the needle into the necrotic lesions. In the navigation experiment of human femoral head specimen, the navigation error of lesion center is less than 2mm. Under the premise of not changing doctors' surgical operation, the navigation system expands surgeons' vision, and the navigation accuracy meets the accuracy requirements of femoral head repair surgery, so it has certain clinical application value.