Korean J Radiol.  2020 Mar;21(3):377-383. 10.3348/kjr.2019.0724.

Feasibility of Adjustable Electrodes for Radiofrequency Ablation of Benign Thyroid Nodules

• Lee J
• Shin JH
• Hahn SY
• Park KW
• Choi JS

• KMID: 2470762
• DOI: http://doi.org/10.3348/kjr.2019.0724

Abstract

OBJECTIVE
The purpose of this study was to evaluate a novel radiofrequency ablation (RFA) application utilizing an adjustable electrode for treatment of benign thyroid nodules.
MATERIALS AND METHODS
From April 2011 to December 2018, 21 patients underwent RFA treatment on 21 thyroid nodules, utilizing an 18-gauge internally cooled electrode equipped with a size adjustable active tip. The peripheral nodule portions were ablated with the moving-shot technique and a shorter active tip, and the nodule centers were ablated with the fixed technique and a longer active tip. We assessed parameters including characteristics of the treated nodules, use of variablesized active tips, volume reduction rate, therapeutic success rate, and post-procedural complications. The therapeutic success rate was defined as a > 50% volume reduction of the initial nodule volume at the 6- or 12-month follow-up.
RESULTS
The treated thyroid nodules were large enough to cause symptoms (mean volume, 29.6 mL). Two types of active tips per session were used for all nodules. The mean volume reduction rate at the last follow-up was 68.3 ± 4.4% and our therapeutic success rate was 90.5%. Both symptoms and cosmetic scores decreased significantly. Minor complications in three patients were recorded during and after the procedure.
CONCLUSION
This initial study demonstrated that an adjustable electrode for RFA of benign thyroid nodules effectively and safely resulted in volume reduction.

Keyword

Thyroid nodule; Ultrasonography; Safety; Radiofrequency ablation

MeSH Terms

Catheter Ablation*
Electrodes*
Follow-Up Studies
Humans
Thyroid Gland*
Thyroid Nodule*
Ultrasonography

Figure

• 

  Fig. 1 Photograph of adjustable RF electrode (18 gauge, total length 8 cm). Simply sliding button enables operator to control length of exposed active tip. RF = radiofrequency

• 

  Fig. 2 Schema of adjustable electrode procedure. Electrode is inserted by trans-isthmic approach. Smaller active tip (right) may be applied to smaller units in periphery of nodule, and larger active tip (left) may be used to ablate larger units in central portion of nodule, thereby completing RFA procedure with single electrode. RFA = radiofrequency ablation

• 

  Fig. 3 RFA using adjustable electrode for benign thyroid nodule. A. 33-year-old woman with thyroid nodule measuring 4.4 cm across largest diameter and 25.5 mL volume. Patient symptom and cosmetic scores were both 4. 1-cm active tip was applied to peripheral portion (B) and 1.5-cm active tip was applied to central portion (C) for treatment of this large-sized nodule. Since nodule was too large to treat in single session, medial section was left untreated (not shown). Additional ablation with fixed electrode was performed for remnant lesion. Six years later, follow-up ultrasound demonstrates that nodule (crosses) (D) has been reduced to 1 mL (volume reduction rate: 96.1%), and symptom and cosmetic scores were 0 and 1, respectively.

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