Radiofrequency and Microwave Ablation as Minimally Invasive Approaches for Managing Benign Thyroid Nodule

Summary

This protocol describes radiofrequency ablation and microwave ablation. Both these techniques can significantly reduce the volume of thyroid nodules while preserving normal thyroid function and minimizing complications, making them the preferred minimally invasive treatments for benign thyroid nodules.

Abstract

The management of benign thyroid nodules has evolved significantly with the advent of minimally invasive techniques, offering patients effective alternatives to traditional surgery. Among these, radiofrequency ablation (RFA) and microwave ablation (MWA) have emerged as the leading modalities. RFA, the most widely adopted method, uses high frequency alternating current to induce thermal coagulation. MWA, though less established in thyroid applications, employs electromagnetic waves to generate rapid and intense heat, making it particularly effective for larger or hypervascular nodules. These approaches are particularly advantageous for patients with symptomatic nodules or cosmetic concerns, as they preserve thyroid function while minimizing complications and recovery time. This protocol establishes a standardized approach for RFA and MWA of benign thyroid nodules. The procedure begins with cytological confirmation (Bethesda II) and ultrasound evaluation, followed by local anesthesia and protective hydrodissection with 40-80 mL of 5% dextrose or distilled water to safeguard critical structures. Under real-time ultrasound guidance, the trans-isthmic approach is employed for needle placement. Ablation is performed at 30-40 W (RFA) or 35-50 W (MWA) using the moving-shot technique. Complete nodule devascularization is confirmed by contrast-enhanced ultrasound (CEUS) during post-ablation assessment, with immediate supplementary ablation being performed if residual enhancement is identified. Clinical and sonographic follow-up is conducted at 1, 3, 6, and 12 months to assess volume reduction ratio, symptom relief, and cosmetic outcomes. The protocol also details the patient selection criteria, technical nuances for cystic/solid nodules, and management of intraoperative complications. This comprehensive guide aims to optimize the reproducibility, safety, and efficacy of thermal ablation for benign thyroid nodules, serving as a practical reference for clinicians adopting these minimally invasive techniques.

Introduction

Thyroid nodules are a prevalent clinical condition, with detection rates increasing significantly due to advancements in imaging techniques, reaching up to 70% in high-frequency ultrasound (US) screenings¹. While the majority (approximately 90%) are benign and asymptomatic, some benign nodules may cause compressive symptoms, neck discomfort, or cosmetic concerns, warranting therapeutic intervention². Surgical resection, though effective, is associated with significant drawbacks, including surgical trauma, permanent hypothyroidism, and suboptimal aesthetic outcomes³.

Im....

Protocol

The protocol in this article describes standard clinical practice. No permission from the ethical committee was needed. All participants provided written consent for the use of identifiable images or clinical data in this publication.

1. Preoperative evaluation and preparation

1. Confirming cytological diagnosis
   1. Perform a fine needle aspiration (FNA) biopsy preoperatively and obtain a cytological diagnosis of a definite benign nodule.
2. Complete preoperative examinations
   1. Conduct routine tests, including complete blood count, coagulation profile, liver and kidney functio....

Results

The clinical characteristics of the enrolled patients are summarized in Table 1.

The volume of the nodules treated with ablation was 8.3 mL (5.0-11.2 mL) at baseline, 4.6 mL (2.6-7.0 mL) at 1 month, 3.5 mL (2.0-5.6 mL) at 3 month, 2.5 mL (1.5-4.3 mL) at 6 month, 1.1 mL (0.5-1.8 mL) at 12 month, and 0.9 mL (0.3-1.6 mL) at the last follow-up period (Table 2). The nodules exhibited a time-dependent volume reduction pattern, showing significant decreases relative .......

Discussion

This study details an optimized ablation protocol where RFA or MWA procedures are dynamically guided by real-time ultrasonography for benign thyroid nodule management. Our protocol's applicability to both RFA and MWA is supported by their shared procedural principles. The primary distinction lies in the ablation device (radiofrequency electrode versus microwave antenna) and power settings, while all other procedural steps, including CEUS-guided assessment, protective hydrodissection, and moving shot technology, remai.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Absolute ethanol	Sigma-Aldrich	459836	sclerotherapy
Hydrodissection needle	BD (Becton, Dickinson and Company)	20G Insyte	hydrodissection
Lauromacrogol	Shaanxi Tianyu Pharmaceutical Co., Ltd.	10ml	sclerotherapy
Lidocaine	Shanghai Harvest Pharmaceutical Co., Ltd.	0.1g, 5ml	local anethesia
Microwave ablation antenna	Nanjing Great Wall Medical Equipment Co., Ltd.	G-18-10	microwave ablation
Microwave ablation apparatus	Nanjing Great Wall Medical Equipment Co., Ltd.	MTI-5AT	microwave ablation
Radiofrequency applicator	Olympus Surgical Technologies	CelonProSurge, micro-100-T15	radiofrequency ablation
Radiofrequency device	Olympus Surgical Technologies	CelonLabPOWER	radiofrequency ablation
Saline solution	Anhui Shuanghe Pharmaceutical Co., Ltd.	100ml	isolation fluid
Saline solution at room temperature or 4°C	Shandong Lukang Chenxin Pharmaceutical Co., Ltd.	500ml	serving as a cooling fluid to reduce the probe tip temperature during ablation
SonoVue	Bracco	-	CEUS agent
Syringe	Shandong Weigao Group Medical Polymer Co., Ltd.	5ml	local anethesia
Syringe	Shandong Weigao Group Medical Polymer Co., Ltd.	20ml	skin dilation; isolation solution injection
Ultrasound machine	Sonoscape Medical Corp.	E5 series	ultrasound guidance