Clinical Application of Computer Navigation in Orthopaedic Bone Tumor Surger

Background Primary bone sarcoma is rare and usually occurs in the young patient group. Wide-local resection with an adequate margin is crucial in the management of this primary bone sarcoma. Inadequate resection margin will result in local tumor recurrence and overall compromise survival of the sarcoma patients. Despite the current best treatment by orthopaedic tumor surgeons and oncologists, about 40% are dying from this fatal condition. For this challenging disease in a demanding patient group, any new technique or technology that may improve the clinical outcomes is urgently needed.;In musculoskeletal oncology, tumor surgeons mentally integrate all the preoperative imaging and formulate a three-dimensional (3D) plan for a tumor resection with clear margin along a desired plane. Conventionally, when surgeons transfer this mental planning to the patient at the operating room, they may use identifiable anatomical landmarks and two-dimensional (2D) measurements based on radiographs to help execute the surgical plan. However, discrepancies between the planned resection and the achieved are expected, particularly in tumor cases at complex anatomical sites such as pelvis and sacrum, or when difficult geometric resections are contemplated.;Purpose This MD thesis described the development of using current computer navigation technology in 3D surgical planning and assisting tumor resection for patients with malignant bone tumors. The new computer-assisted tumor surgery (CATS) technique was proposed to help surgeons accurately reproduce surgical plans, so to reduce human errors when treating patients with bone cancers. The improved accuracy in tumor resection may then translate to better oncological and functional results.;Methods A commercially available CT-based navigation system (CT spine, version 1.6, Stryker) was selected for the studies in this thesis. The navigation system is originally designed for pedicle screw placement in spinal surgery. Instead of using the navigation technology solely for intraoperative image guidance, a fusion of multimodal preoperative images was also investigated for any benefits in surgical planning. The clinical workflow of CATS technique was developed. It was first used in a patient with solitary pelvic bone metastasis and then in 20 patients with bone tumors at various musculoskeletal regions. The surgical accuracy, oncological and functional results were evaluated.;Results Our results show that the navigation system could be used to real-time track tumor bones in different musculoskeletal regions. With the help of fused CT and MR images and intraoperative navigation guidance, we were able to locate anatomical and pathological structures without having to rely on subjective assessments and interpretation of imaging datasets at the time of surgery.;At the mid-term follow-up of 7 years, the clinical results using the CATS technique suggested that it allows surgeons to replicate the intended bone resections in bone tumors accurately. The new technique is particularly helpful in technically demanding procedures, such as pelvic and sacral tumor resection, joint-preserving intercalated and multiplanar tumor resection, and complex reconstruction with a custom CAD prosthesis. The technique was safe as the complications in our clinical series were comparable to those with the conventional technique in the literature.;Conclusions Based on our results, we believe that the CATS technique can be regarded as a useful tool for assisting surgery of complex malignant bone tumors. Comparative clinical studies with more cases and longer follow-up period are needed to determine whether increased accuracy in tumor resection and reconstruction lead to better oncologic and functional outcomes. The work has led to the development of navigation software that is dedicated to orthopaedic tumor surgery, advances in CAD implant design and form the basis of 3D printing applications in bone tumor surgery.