The Mangement Of Bone Metastases By CT-guided Percutaneous Microwave Ablation

Objective:To analyze clinic applications to treat bone metastases by microwave ablation to assess the safety and effectivity of the CT-guided percutaneous microwave ablation.Materials and Methods:Bone metastases were common from many kinds of prirary cancers. They were the most common cause of cancer-related pain. Painful skeletal metastases were a common problem in cancer patients. Although external beam radiation therapy was the current standard of care for cancer patients who presented with localized bone pain,20-30% of patients treated with this modality did not experience pain relief, and few further options existed for these patients. For many patients with painful metastatic skeletal disease, analgesics remained the only alternative treatment option. Recently, image-guided percutaneous methods of tumor destruction had proven effective for treatment of this difficult problem. Ji jingtao and colleagues described to analyze the heat distribution and heat coagulation of osteoid osteoma treating by microwave ablation in vitro animal model and clinic applications to assess the safety and effectivity of the CT-guided percutaneous microwave ablation. The temperature was 78.5℃,44.0℃and 34.2℃at 0,5, and 10 mm from the periosteum, respectively. The extent of coagulation necrosis in the pig's long bone with microwave ablation was a globular-shaped region of approximately 1.5cm diameter. The pain of 3 patients of osteoid osteoma was alleviated 24h after operation. We based this theory and clinic application, From September 2009 to December 2010, 7 patients with bone metastases were treated with CT-guided percutaneous microwave ablation in clinical applications. There were 6 males and 1 female with an average age of 54.9 years (ranging from 27 to 83 years). The history of local pain was ranging from 3 month to 2 years. The lesion location contained:2 cases in the pelvis, 1 case in the forth lumbar,1 case in the right rib,1 case in the sacrum,1 case in scapular metastasis and 1 case in proximal humerus. All patients had the clinical diagnosis of bone metastases with clinical and radiologic evidence. After localization of the nidus with CT, osseous access was established with a "Gallini" puncturatio needle. After scanning the nidus with CT, Subsequently, a microwave probe was introduced through the biopsy needle to the nidus. Microwave ablation was performed at 90℃for 4～6 minutes.Results:The pain of 7 patients was alleviated 24 h after operation. No complications appeared in the operations.1 case with history of local pain 2 years retained discomfortableness after the operation, and disappeared after 1 weeks.1 case with lesion in the forth lumbar pain reappeared after 3 months, this patient'pain score was 8 (VAS). He was operated with lesion remove and internal fixation with pedicle screws and bone cement, the patient's pain had decreased from 8/10 to 1/101 weeks after treatment, retained pain without nonsteroidal antiinflammatory drugs 5 month after operation. This one died after 6 months of the second operation. No recurrence and complications were observed.Conclusion:CT-guided percutaneous microwave ablation is a simple, minimally invasive, safe, highly effective and economical technique for treatment of bone metastases.