Treatment of metastatic posterior vertebral body osseous tumors by using a targeted bipolar radiofrequency ablation device: technical note

Purpose: To evaluate the feasibility of use and safety of a targeted radiofrequency ablation (RFA) device for metastatic posterior vertebral body tumors.

Materials and methods: This retrospective study was institutional review board approved and HIPAA compliant. Consent was waived for retrospective participation. Fluoroscopic or computed tomography-guided targeted RFA was performed in 26 patients (47 tumors) with painful metastatic posterior vertebral body tumors, some of which were radiation therapy resistant, by using a newly developed spinal tumor ablation system that contains an articulating bipolar extensible electrode. In 14 women and 12 men aged 44-85 years (mean age, 62 years), the most common primary tumor was lung cancer in seven patients (27%) and renal cell carcinoma and sarcoma in five patients each (19%). Other tumors included breast cancer and melanoma in two patients each (8%) and colon cancer, multiple myeloma, neuroendocrine tumor, head and neck squamous cell carcinoma, and unknown primary tumor in one patient each (4%). Ablation was performed with device thermocouples that permitted real-time monitoring of the periphery of the ablation zones to determine ablation size. Sequential postprocedural pain scores were obtained. Thirteen patients underwent follow-up imaging, and one underwent subsequent biopsy of a treated area. A paired two-tailed Student t test was used to evaluate significance of postoperative visual analog scale scores of pain at 1 week and 1 month.

Results: Four of 26 patients developed transient radicular symptoms after ablation, which resolved with transforaminal blocks. No permanent neurologic injuries resulted from the procedure. Intraprocedural imaging demonstrated that the articulating bipolar instrument could be navigated into the posterior vertebral body tumors with a transpedicular approach. Postablation imaging confirmed necrosis within the ablation zone. Three patients showed progression of disease at the treated levels at follow-up. Systemic therapy was not interrupted to perform the procedures.

Conclusion: Targeted RFA with a newly developed articulating device is both feasible and safe for the treatment of painful posterior vertebral body metastatic tumors.