Abstract No. 491 Simultaneous bipedicular radiofrequency ablation for local tumor control of vertebral metastases

Abstract

To evaluate the safety and effectiveness of simultaneous bipedicular radiofrequency ablation (RFA) for local tumor control of vertebral metastases. Thirty-five spinal lesions in 29 patients were treated, of which 31/35 (89%) and 19/35 (54%) involved the posterior vertebral body and pedicle, respectively. Sixty percent of the lesions involved 75% or more of the vertebral body. Lesions were treated with two articulating, navigational bipolar RFA probes (STAR, Merit) simultaneously to allow more confluent overlapping ablation zone to encompass as much vertebral body volume as possible while minimizing risk of thermal injury and impedance by using variable wattage (3, 5, 7.5, or 10 watts). Mean total ablation times per probe were 18.3 minutes (range, 9.9–29.3) with overlapping ablations zones performed anteriorly, posteriorly, and within the pedicle. Postablation cementoplasty was performed in all cases via the same introducer cannula. Complications were assessed based on the Society of Interventional Radiology classification. Postprocedure local tumor control was defined as the absence of residual enhancement on contrast-enhanced MRI, radiotracer activity on PET, or stability of osteolysis on CT. All lesions were successfully ablated without any complications or thermal injury. Of the 28 lesions with postprocedure imaging, local tumor control was observed in 96% (27/28) of cases at a mean follow-up of 12.7 weeks (range, 1–48). Retraction of epidural tumor was seen in 3 cases. Simultaneous bipedicular RFA is safe and effective in the treatment of vertebral metastases, including those involving the posterior vertebral body and pedicle. This novel technique supports the stereotactic spine radiation surgery paradigm to treat the entire vertebral body and pedicles (i.e. clinical target volume) to account for microscopic disease and marginal failures for better local tumor control rates and more durable pain relief.