2:02 PM Abstract No. 85 - Image-guided targeted radiofrequency ablation (t-RFA) of spinal tumors using a novel bipolar navigational device: multicenter initial clinical experience

Abstract

Purpose Report initial clinical experience and determine the efficacy and safety of targeted radiofrequency ablation (t-RFA) of malignant spinal lesions using a novel bipolar RF ablation system. Demonstrate the use of temperature monitoring of thermocouples (TC) on an articulating electrode to determine ablation size and morphology with use of post-ablation magnetic resonance imaging (MRI) and comparison with pre-clinical thermal distribution curves. Materials and Methods 101 spinal lesions in 73 procedures were treated at six centers. The STAR Tumor Ablation System includes a robust articulating, navigational bipolar electrode containing two active TCs positioned to permit real time monitoring of the peripheral edge of the ablation zone to determine size of ablation. Treatment was controlled by adjusting power while monitoring TC temperature in-situ. Access and number of ablations were based on lesion size, location and ability to articulate the bipolar electrode. Cement augmentation via the same guiding cannula was performed when required. In some cases, post-procedural MRI was performed. Pain was assessed pre- and postprocedurally. Results Lesion etiology included a wide variety of metastatic lesions from T2 to S2 and ilium. No complications or thermal injury occurred. Cement augmentation following t-RFA was efficient and resulted in predictable cement filling. Postablation MRIs demonstrated discrete ablation zones with 3:2 length-to-width aspect ratio consistent in size with thermal monitoring by TCs during the ablation. All patients reported pain relief. Conclusion The STAR device was safely and effectively used in the navigation and t-RFA of spinal malignant lesions. Postablation MRIs confirmed lesions were included in the ablation zone with necrosis of the lesion. The ablation zone was consistent in size with that measured by the TCs and similar in morphology to that extrapolated from thermal distribution curves. The STAR navigational ability allowed for easy access to posterior vertebral body lesions, previously difficult to access with other ablation devices. In many cases, this technique allowed for treatment of individual lesions not controlled by systemic or radiation therapy.