A Cadaveric Comparative Study on the Surgical Accuracy of Freehand, Computer Navigation, and Patient-Specific Instruments in Joint-Preserving Bone Tumor Resections.

Orthopedic oncologic surgery requires preservation of a functioning limb at the essence of achieving safe margins. With most bone sarcomas arising from the metaphyseal region, in close proximity to joints, joint-salvage surgery can be challenging. Intraoperative guidance techniques like computer-assisted surgery (CAS) and patient-specific instrumentation (PSI) could assist in achieving higher surgical accuracy. This study investigates the surgical accuracy of freehand, CAS- and PSI-assisted joint-preserving tumor resections and tests whether integration of CAS with PSI (CAS + PSI) can further improve accuracy. CT scans of 16 simulated tumors around the knee in four human cadavers were performed and imported into engineering software (MIMICS) for 3D planning of multiplanar joint-preserving resections. The planned resections were transferred to the navigation system and/or used for PSI design. Location accuracy (LA), entry and exit points of all 56 planes, and resection time were measured by postprocedural CT. Both CAS + PSI- and PSI-assisted techniques could reproduce planned resections with a mean LA of less than 2 mm. There was no statistical difference in LA between CAS + PSI and PSI resections (p=0.92), but both CAS + PSI and PSI showed a significantly higher LA compared to CAS (p=0.042 and p=0.034, respectively). PSI-assisted resections were faster compared to CAS + PSI (p < 0.001) and CAS (p < 0.001). Adding CAS to PSI did improve the exit points, however not significantly. In conclusion, PSI showed the best overall surgical accuracy and is fastest and easy to use. CAS could be used as an intraoperative quality control tool for PSI, and integration of CAS with PSI is possible but did not improve surgical accuracy. Both CAS and PSI seem complementary in improving surgical accuracy and are not mutually exclusive. Image-based techniques like CAS and PSI are superior over freehand resection. Surgeons should choose the technique most suitable based on the patient and tumor specifics.

Delay in Diagnosis and Its Effect on Clinical Outcome in High-grade Sarcoma of Bone: A Referral Oncological Centre Study.

OBJECTIVE: To investigate delay in diagnosis by both patients and doctors, and to evaluate its effect on outcomes of high-grade sarcoma of bone in a single-referral oncological center. METHODS: Fifty-four patients with osteosarcoma, 29 with Ewing sarcoma and 19 with chondrosarcoma were enrolled in this retrospective study. Delay in diagnosis was defined as the period between initial clinical symptoms and histopathological diagnosis at our center. The delays were categorized as patient- or doctor-related. Short total delays were defined as <4 months; prolonged delays >4 months were assumed to have prognostic relevance. RESULTS: Total delay in diagnosis was 688.0 days in patients with chondrosarcoma, which is significantly longer than the 163.3 days for osteosarcoma (P < 0.01) and 160.2 days for Ewing sarcoma (P < 0.01). Most doctor-related delays were at the pre-hospital stage, occurring at the general practitioner (GP)'s office. However, prolonged total delays (≥4 months) did not result in lower survival rates. Five-year-overall survival rates were 67.0% for osteosarcoma, 49.0% for Ewing sarcoma and 60.9% for chondrosarcoma. Survival was significantly lower for patients with metastatic disease for all three types of sarcoma. CONCLUSION: Prolonged delay in diagnosis does not result in lower survival. Metastatic disease has a pronounced effect on survival. Aggressive tumor behavior results in shorter delays. Minimizing GP-related delays could be achieved by adopting a lower threshold for obtaining plain radiographs at the pre-hospital stage.

Local Treatment with Adjuvant Therapy for Central Atypical Cartilaginous Tumors in the Long Bones: Analysis of Outcome and Complications in One Hundred and Eight Patients with a Minimum Follow-up of Two Years.

BACKGROUND: A central atypical cartilaginous tumor (ACT)--formerly known as chondrosarcoma grade 1 (CS1)--is a tumor of intermediate-type malignancy, often treated with surgery. The extent of surgery remains controversial, as some advocate resection and others favor local treatment by curettage. Because of the low prevalence of ACT/CS1, the available data are limited and generally not uniform. The purpose of this study was to present the outcome for a large cohort of patients with ACT/CS1 in the long bones who were treated with curettage and adjuvant phenolization and followed for a minimum of two years according to national guidelines. METHODS: A retrospective study was designed to analyze data from 108 patients treated for central ACT/CS1 in the long bones between 2006 and 2012. All patients were treated with curettage and adjuvant phenolization, and defects were filled with polymethylmethacrylate, bone graft, or bone substitutes. The primary end point was local recurrence or residual tumor. Secondary end points included the type and rate of complications and reoperations. RESULTS: All patients were free from local recurrence at a mean follow-up of 48.7 months (range, 24.3 to 97.5 months). Residual tumor was suspected in five patients, leading to a 95.4% disease-free survival rate. A fracture occurred in eleven patients (10.2%). Other complications were osseous penetration during the surgery (two patients), wound infection (one patient), arthrofibrosis (one patient), and skin necrosis (one patient). Tumor volume was related neither to the risk of fracture nor to the occurrence of residual tumor. CONCLUSIONS: In our experience, curettage of ACT/CS1 in the long bones with adjuvant phenolization is safe, even with large tumors of up to 100 cm(3). Most worrisome is the risk of fracture, which occurred in 10.2% of our patients. Considering the relatively mild behavior of ACT/CS1, less aggressive treatment, by observation or by minimally invasive surgery, could be the next step that should be evaluated prospectively.

Computer-assisted surgery in orthopedic oncology.

BACKGROUND AND PURPOSE: In orthopedic oncology, computer-assisted surgery (CAS) can be considered an alternative to fluoroscopy and direct measurement for orientation, planning, and margin control. However, only small case series reporting specific applications have been published. We therefore describe possible applications of CAS and report preliminary results in 130 procedures. PATIENTS AND METHODS: We conducted a retrospective cohort study of all oncological CAS procedures in a single institution from November 2006 to March 2013. Mean follow-up time was 32 months. We categorized and analyzed 130 procedures for clinical parameters. The categories were image-based intralesional treatment, image-based resection, image-based resection and reconstruction, and imageless resection and reconstruction. RESULTS: Application to intralesional treatment showed 1 inadequate curettage and 1 (other) recurrence in 63 cases. Image-based resections in 42 cases showed 40 R0 margins; 16 in 17 pelvic resections. Image-based reconstruction facilitated graft creation with a mean reconstruction accuracy of 0.9 mm in one case. Imageless CAS was helpful in resection planning and length- and joint line reconstruction for tumor prostheses. INTERPRETATION: CAS is a promising new development. Preliminary results show a high number of R0 resections and low short-term recurrence rates for curettage.