Navigation Surgery for Bone and Soft Tissue Tumor

Inclusion criteria: 1. First condition is that the benign tumor is located deeply in bones of extremities, or pelvis, so we anticipate the difficulty to find the tumor and to assess the adequacy of resection without the aid of computer-assisted navigation during operation. 2. Second condition is when the violation of joint or growth plate is expected during removal of tumor due to its close proximity to joint or growth plate. In case of malignant bone tumor, the sufficient preservation of joint anatomy should be required even with resection margin of 1.5 cm away from reactive zone of tumor. The sufficient preservation of joint is defined when at least 1 cm subchondral bone is remained after tumor resection, because 1 cm subchondral bone is required for fixation with allograft in subsequent reconstruction. The sufficient preservation of joint is also defined when articular surface is removed, but more than 50% of articular surface has to be saved. Exclusion criteria were 1. Patients who denied to perform navigation surgery after explanation of navigation surgery protocol 2. Medically high-risk patients who could not withstand long surgical time for joint reconstruction 3. Patients whose feasibility of joint preservation was not fulfill the above inclusion criteria at initial presentation, although the tumor size was decreased enough to fulfill the inclusion criteria in MRI after completion of neoadjuvant chemotherapy.