Temperature distribution during radiofrequency ablation of spinal metastases in a human cadaver model: Comparison of three electrodes.

Abstract

Radiofrequency ablation (RFA) temperatures reaching 45°C in adjacent tissues are cytotoxic to the spinal cord, nerves and surrounding tissues. This study compares different RFA electrodes with regard to the temperature distribution during ablation of spinal metastases. In vitro experimental study in isolated lumbar vertebrae of a human cadaveric spine. The temperature distribution of RFA electrodes was measured during ablation in human cadaveric lumbar vertebrae containing a simulated vertebral body lesion. The analysis compared a novel bipolar RFA electrode with two conventional monopolar RFA electrodes. A vertebral metastasis model was prepared in eight lumbar vertebrae for each electrode. Differences between the electrodes were evaluated with a one-way ANOVA. The lowest temperature at the thermocouples adjacent to the simulated lesion was achieved when using the bipolar RFA electrode (46.4 ± 3.3°C), but temperature difference to the monopolar RFA electrodes was not significant. In the neural foramen and epidural space of lumbar vertebrae the maximal temperature measured when using the bipolar RFA electrode was 37.0 ± 0°C and 37.3 ± 0.7°C, which was significantly lower than during ablation via either of the monopolar RFA electrodes (p ≤ 0.001). Temperatures in areas of adjacent tissue during RFA using a specific for spinal ablation designed electrode with integrated thermocouples were significantly lower compared to other electrodes, potentially reducing temperature related risks during ablation.