Surgical precision in oncologic surgery is essential to achieve adequate margins in bone tumor resections. Three-dimensional preoperative planning and bone tumor resection by navigation have been introduced to orthopedic oncology in recent years. However, the accuracy of preoperative planning and navigation is unclear. The purpose of this study was to evaluate the accuracy of preoperative planning and the navigation system. A total of 28 patients were evaluated between May 2010 and February 2011. Tumor locations were the femur (n=17), pelvis (n=6), sacrum (n=2), tibia (n=2), and humerus (n=1). All resections were planned in a virtual scenario using computed tomography and magnetic resonance imaging fusion. A total of 61 planes or osteotomies were performed to resect the tumors. Postoperatively, computed tomography scans were obtained for all surgical specimens, and the specimens were 3-dimensionally reconstructed from the scans. Differences were determined by finding the distances between the osteotomies virtually programmed and those performed. The global mean of the quantitative comparisons between the osteotomies programmed and those obtained through the resected specimen was 2.52±2.32 mm for all patients. Differences between osteotomies virtually programmed and those achieved by navigation intraoperatively were minimal.

Background Central chondrosarcoma of bone is graded on a scale of 1 to 3 according to histological criteria. Clinically, these tumors can be divided into low-grade (Grade 1) and high-grade (Grade 2, Grade 3, and dedifferentiated) chondrosarcomas. Although en bloc resection has been the most widely used treatment, it has become generally accepted that in selected patients with low-grade chondrosarcomas of long bones, curettage is safe and effective. This approach requires an accurate preoperative estimation of grade to avoid under-or overtreatment, but prior reports have indicated that both imaging and biopsy do not always give an accurate prediction of grade. Questions/purposes (1) What is the concordance of image-guided needle preoperative biopsy and postoperative grading in central (intramedullary) chondrosarcomas of long bones, and how does this compare with the concordance of image-guided needle preoperative biopsy and postoperative grading in central pelvic chondrosarcomas? (2) What is the concordance of preoperative image-guided needle biopsy and postoperative findings in differentiating low-grade from high-grade central chondrosarcomas of long bones, and how does this compare with the concordance in central pelvic chondrosarcomas? Methods Between 1997 and 2014, in our institution, we treated 126 patients for central chondrosarcomas located in long bones and the pelvis. Of these 126 cases, 41 were located in the pelvis and the remaining 85 cases were located in long bones. This study considers 39 (95%) and 40 (47%) of them, respectively. We included all cases in which histological information was complete regarding preoperative and postoperative tumor grading. We excluded all cases with incomplete data sets or nondiagnostic preoperative biopsies. To evaluate the needle biopsy accuracy, we compared the histological tumor grade, obtained from the preoperative biopsy, with the final histological grade obtained from the postoperative surgical specimen. The weighted and nonweighted kappa statistics were used to evaluate the agreement. Results Concordance between the preoperative biopsy and the final pathological analysis in terms of histological grade was much higher in long-bone chondrosarcoma than in pelvic chondrosarcoma (83% [33 of 40] versus 36% [14 of 39]; odds ratio, 8, 48). Likewise, the weighted kappa coefficients were higher in long-bone chondrosarcoma than One of the authors certifies that he (LAA-T) or a member of his immediate family, has or may receive payments or benefits, during the study period, an amount of USD 10,000 to USD 100,000 from Stryker Americas (Miramar, FL, USA). All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research 1 editors and board members are on file with the publication and can be viewed on request. Each author certifies that his institution has approved the reporting of this study and that all investigations were conducted in conformity with ethical principles of research. This work was performed at the Italian Hospital of Bue...

Background Computer navigation during surgery can help oncologic surgeons perform more accurate resections. However, some navigation studies suggest that this tool may result in unique intraoperative problems and increased surgical time. The degree to which these problems might diminish with experience-the learning curve-has not, to our knowledge, been evaluated for navigation-assisted tumor resections. Questions/purposes (1) What intraoperative technical problems were observed during the first 2 years using navigation? (2) What was the mean time for navigation procedures and the time improvement during the learning curve? (3) Have there been any differences in the accuracy of the registration technique that occurred over time? (4) Did navigation achieve the goal of achieving a wide bone margin? Methods All patients who underwent preoperative virtual planning for tumor bone resections and operated on with navigation assistance from 2010 to 2012 were prospectively collected. Two surgeons (GLF, LAA-T) performed the intraoperative navigation assistance. Both surgeons had more than 5 years of experience in orthopaedic oncology with more than 60 oncology cases per year per surgeon. This study includes from the very first patients performed with navigation. Although they did not take any formal training in orthopaedic oncology navigation, both surgeons were trained in navigation for knee prostheses. Between 2010 and 2012, we performed 124 bone tumor resections; of these, 78 (63%) cases were resected using intraoperative navigation assistance. During this period, our general indications for use of navigation included pelvic and sacral tumors and those tumors that were reconstructed with massive bone allografts to obtain precise matching of the host and allograft osteotomies. Seventy-eight patients treated with this technology were included in the study. Technical problems (crashes) and time for the navigation procedure were reported after surgery. Accuracy of the registration technique was defined and the surgical margins of the removed specimen were determined by an experienced bone pathologist after the surgical procedure as intralesional, marginal, or wide margins. To obtain these One of the authors certifies that he (LAA-T) or a member of his immediate family, has or may receive payments or benefits, during the study period, an amount of USD 10,000 to USD 100,000 from Stryker Americas (Miramar, FL, USA 123 Clin Orthop Relat Res (2017) 475:668-675 DOI 10.1007/s11999-016-4761-z Clinical Orthopaedics and Related Research ® A Publication of The Association of Bone and Joint Surgeons® data, we performed a chart review and review of operative notes.Results In four patients (of 78 [5%]), the navigation was not completed as a result of technical problems; all occurred during the first 20 cases of the utilization of this technology. The mean time for navigation procedures during the operation was 31 minutes (range, 11-61 minutes), and the early navigations took more time (the regression analysis shielded R 2 = 0.35 ...