A preliminary comparative study of three different microwave ablation methods for cystic-solid thyroid nodules

This preliminary comparative study assessed the effectiveness of three microwave ablation (MWA) techniques in managing cystic-solid thyroid nodules.

Patients who underwent MWA from January 2018 to October 2021 at the Second Affiliated Hospital of Shantou University Medical College were divided into three groups: Simple Aspiration Group (SAG) (cyst fluid drained before direct ablation), Epinephrine Solution Immersion Group (ESIG) (cyst fluid drained followed by soaking in epinephrine), and High-Power Ablation Group (HPAG) (immediate high-power ablation after drainage). Twenty patients were retrospectively analyzed in each group, comparing intraoperative intracapsular bleeding, ablation time of cystic-solid nodules, 12th-month nodule volume reduction rate (VRR), preoperative cosmetic and symptom scores, and postoperative scores.

Significant differences were observed in intraoperative intracapsular rebleeding (≥50% cyst cavity volume) between ESIG and SAG (p = 0.029) and HPAG and SAG (p = 0.008), but not between ESIG and HPAG (p = 0.602). The ablation time for cystic-solid nodules was shorter in ESIG and HPAG compared to SAG (p = 0.003 and p = 0.006, respectively), with no significant difference between ESIG and HPAG (p = 0.689). However, the 12th-month outcomes-VRRs, symptom scores, and cosmetic scores-showed no statistical significance among the groups (p = 0.634, p = 0.329, and p = 0.717, respectively).

ESIG and HPAG significantly reduced intraoperative intracapsular bleeding and ablation time of solid-cystic nodules compared with SAG, indicating enhanced procedural efficiency. Nevertheless, the long-term therapeutic outcomes (nodule shrinkage, symptom relief, and cosmesis) were similar across all methods. These findings underscore the potential of epinephrine immersion and high-power ablation in optimizing MWA for cystic-solid nodules.