Treatment Planning and Fracture Prediction in Patients with Skeletal Metastasis with CT-Based Rigidity Analysis.

PURPOSE: Pathologic fractures could be prevented if reliable methods of fracture risk assessment were available. A multicenter prospective study was conducted to identify significant predictors of physicians' treatment plan for skeletal metastasis based on clinical fracture risk assessments and the proposed CT-based Rigidity Analysis (CTRA). EXPERIMENTAL DESIGN: Orthopedic oncologists selected a treatment plan for 124 patients with 149 metastatic lesions based on the Mirels method. Then, CTRA was performed, and the results were provided to the physicians, who were asked to reassess their treatment plan. The pre- and post-CTRA treatment plans were compared to identify cases in which the treatment plan was changed based on the CTRA report. Patients were followed for a 4-month period to establish the incidence of pathologic fractures. RESULTS: Pain, lesion type, and lesion size were significant predictors of the pre-CTRA plan. After providing the CTRA results, physicians changed their plan for 36 patients. CTRA results, pain, and primary source of metastasis were significant predictors of the post-CTRA plan. Follow-up of patients who did not undergo fixation resulted in 7 fractures; CTRA predicted these fractures with 100% sensitivity and 90% specificity, whereas the Mirels method was 71% sensitive and 50% specific. CONCLUSIONS: Lesion type and size and pain level influenced the physicians' plans for the management of metastatic lesions. Physicians' treatment plans and fracture risk predictions were significantly influenced by the availability of CTRA results. Due to its high sensitivity and specificity, CTRA could potentially be used as a screening method for pathologic fractures.

Atypical growth on MRI in a case of Ewing's sarcoma despite lower SUV on PET.

Ewing's sarcoma is a rare primary bone malignancy of small round blue cells. Treatment typically consists of neoadjuvant chemotherapy, surgical resection, and adjuvant chemotherapy. The disease response to chemotherapy can be followed with fluorodeoxyglucose (FDG) positron emission tomography (PET), which measures the metabolic activity of the tumor, and by magnetic resonance imaging (MRI), which measures tumor size. We present a unique case in which the tumor grew in size following neoadjuvant chemotherapy but decreased in metabolic activity, making it difficult to judge efficacy of the chemotherapy. An atypical response to chemotherapy in this case caused tumor growth due to a fibrotic reaction while viable tumor cells were eradicated. This case highlights the ability of FDG-PET scan to identify the uncommon situation in which a tumor that increased in size may have had a favorable response to chemotherapy. This possibility should be considered in similar cases in which FDG-PET scan shows diminishing metabolic activity despite tumor growth.

The practicing orthopedic surgeon's guide to managing long bone metastases.

Long bone skeletal metastases are common in the United States, with more than 280,000 new cases every year. Most of these will be managed by the on-call orthopedic surgeon. A practical primer is offered for the evaluation and surgical management for the practicing orthopedist, including questions to ask during the history, pertinent physical examination findings, appropriate imaging requests, proper laboratory work, and biopsy options. Finally, 7 scenarios are presented to encompass most situations a practicing orthopedic surgeon will encounter, and guidelines for treatment and referral are offered.