Study On Computer-aided Orthopedic System For Spinal Surgery Based On Volume Visualization

Spinal orthopaedic surgery is difficult and its risk is high, as the operation involves complex tissues such as bone structures and nervous system. With the in-depth application of visualization technology in medicine, spinal clinical diagnosis and treatment are assisted effectively. In the computer-aided operation, 3D reconstruction of the spine model, the use of measuring, cutting and registration positioning greatly improved the accuracy of preoperation, that completely changed the traditional treatment mode, and greatly improved the success rate of surgery. While how to use the volume visualization technology to provide high quality 3D images, and how to develop a system with friendly interactive performances to meet the needs of orthopedic surgical precision and safety requirements, become the urgent problems to solve.This thesis is mainly for the practical requirements of spinal surgery, and establishes a computer-aided orthopedic system. Aiming at the above problems, I intensely researched the high-quality volume visualization techniques, the technology of orthopedic surgery interactive simulation and its implementation. In general, the main research results are as follows:1)To achieve high quality 3D reconstruction, the thesis focused on the visualization technology of surface rendering and volume rendering algorithms, combinated the two rendering results to show the complementary information to doctors. It achieved drawing the isosurfaces based MC algorithm and considering all the details of the process of ray casting algorithm, got the implement based on GPU isosurface, material indexed and improved Blinn-Phong lighting model volume rendering. In both models, the surface smoothness and realistic image well meet the real-time rendering.2) In the development of orthopedic spine surgery scheme, spinal lesions regional organizations of pathological conditions are in need. The thesis examined the interaction based on volume rendering algorithm, designed a functional areas. And in adequate consideration of the possibility occlusion between the soft tissue and the spine, the closed irregular cutting method is developed without affecting the rendering efficiency, so we can get osteotomy sites by unobstructed observing, and it offers guidance to surgery under the surface rendering.3) To assist in designing surgery program, I studied computer-aided surgery techniques based on the surface rendering, registration method and rapid prototyping technology. I have understood deeply the principles of position transform, analyzed the 3D graphics picking mechanism to achieve the model coordinate locationing and measurement and discussed the cutting methods of triangular facets, and the use of rigid registration techniques for consistent reference point after spinal osteotomy. In order to facilitate data transmission among CAD systems, this paper saved triangular facets group into STL file.4) The system of computer-aided orthopedic surgery for spinal deformity is finally established based on the above researches. The design solution, overall framework, function modules and key technologies are discussed in detail; Simulation results show that: the system can more intuitively, accurately reflect the orthopedic effect, and it can provide a more scientific basis for surgical planning, while it also has better scalability and engineering reference value.