Thyroid RFA procedure
The patient should be positioned in supine with neck slightly extended. Local anesthetic with lignocaine is then injected underneath the skin near the cervical-surrounding soft tissue and thyroid capsule.
S. Spiezia, R. Garberoglio, F. Milone et al., “Thyroid nodules and related symptoms are stably controlled two years after radiofrequency thermal ablation,” Thyroid, vol. 19, no. 3, pp. 219–225, 2009.
J. H. Baek, Y. S. Kim, J. Y. Sung, H. Choi, and J. H. Lee, “Locoregional control of metastatic well-differentiated thyroid cancer by ultrasound-guided radiofrequency ablation,” American Journal of Roentgenology, vol. 197, no. 2, pp. W331–W336, 2011.
J. H. Baek, H. J. Jeong, Y. S. Kim, M. S. Kwak, and D. Lee, “Radiofrequency ablation for an autonomously functioning thyroid nodule,” Thyroid, vol. 18, no. 6, pp. 675–676, 2008
Some would also administer premedication of fentanyl and midazolam to minimize discomfort.
J. M. Monchik, G. Donatini, J. Iannuccilli, and D. E. Dupuy, “Radiofrequency ablation and percutaneous ethanol injection treatment for recurrent local and distant well-differentiated thyroid carcinoma,” Annals of Surgery, vol. 244, no. 2, pp. 296–304, 2006.
Grounding pads are adhered to both thighs and are connected to RF generator, and the generator was connected to RF electrode in unipolar systems only.
The “moving shot” technique is the method of choice. This technique was first described by Baek et al. in Seoul, Korea.
W. K. Jeong, J. H. Baek, H. Rhim et al., “Radiofrequency ablation of benign thyroid nodules: safety and imaging follow-up in 236 patients,” European Radiology, vol. 18, no. 6, pp. 1244–1250, 2008.
A straight internally-cooled short thin electrode is used. The electrode is usually 15 cm in (7 cm shaft length) and smaller (18-19 gauge) electrode with active tips around 0.5, 0.7, 1, 1.5, and 2 cm.
J. H. Baek, J. H. Lee, R. Valcavi, C. M. Pacella, H. Rhim, and D. G. Na, “Thermal ablation for benign thyroid nodules: radiofrequency and laser,” Korean Journal of Radiology, vol. 12, no. 5, pp. 525–540, 2011
With these shorter and smaller electrode, it allows better control and variation of ablation option in treating small or vital structure closed thyroid nodule. The “moving shot technique”, targets thyroid nodule in divided units and during the procedure, each conceptual unit is being ablated by the moving ablation electrode tip. The electrode is inserted through the isthmus under the US guidance. The whole course of electrode could be seen and that greatly reduces the risk of injury of the nearby structures. The ablation first starts from the deepest layer up and so the electrode is slowly withdrawn to the surface.
It is important that the region close to the trachea-esophageal groove be less treated in order to avoid injury to the recurrent laryngeal nerve, trachea, and esophagus as this area is often referred to as the “danger triangle”.
Richard Guttler MD,FACE,ECNU
Clinical Professor of Medicine Keck/USC school of Medicine
Director, Santa Monica Thyroid Center, Santa Monica Ca 90404
Member, American Association of Clinical Endocrinologist’s task force on the introduction of thyroid radiofrequency ablation RFA of thyroid nodules to the United States.