Safety and Technical Efficacy of Tumescent Anesthesia in Radiofrequency Ablation for Thyroid Nodules Close to the Surrounding Structure

Purpose: This study estimated the changes in distance between a thyroid nodule and the surrounding structures after tumescent anesthesia in radiofrequency ablation (RFA) for a benign thyroid nodule. Methods: Between January 2015 and December 2017, the sonogram images in patients treated with thyroid RFA were reviewed retrospectively. Patients without images immediately after tumescent anesthesia or treated with RFA for carcinoma were excluded. The 0.2% saline mixed lidocaine as a tumescent solution was injected into the anterior, posterior, and lateral capsules of the thyroid and thyroid-trachea junction. In a sonogram image, the distances between the posterior margin of the nodule and above the longus colli muscle, between the medial margin of the nodule and trachea, and between the lateral margin of the nodule and common carotid artery (CCA) were measured before and after tumescent anesthesia. Results: Tumescent anesthesia was technically successful in all 133 patients (100%) and the analgesic effect was also obtained successfully. No complications related to tumescent anesthesia were observed. The average distance between the posterior margin of the nodule and the longus colli muscle increased by 4.2 ± 2.4 mm. The average distance between the medial margin of the nodule and trachea increased by 2.2 ± 1.9 mm. The average distance between the lateral margin of the nodule and CCA increased by 4.6 ± 3.0 mm. Conclusion: Tumescent anesthesia is a safe and useful method for secure a safe distance (over 2 mm) in RFA for thyroid nodules close to the surrounding structure.