The iceberg technique: an innovative approach for radiofrequency ablation of diving thyroid nodules.

Diving thyroid nodules are a limitation of radiofrequency ablation because the mediastinal component cannot be adequately identified by ultrasound (US). We aim to describe a new technique, the iceberg technique, to overcome this issue and explain our three-year experience of using this novel method. The iceberg technique consists of a two-stage treatment. First, the ablation of the cervical portion of the nodules (easily visualized during the initial US exam) using trans-isthmic access is performed using the moving-shot technique. After three to six months, there is a volumetric reduction of the treated portion, leading to retraction of the thyroid parenchyma. This brings the mediastinal component to the cervical region, thereby enabling a perfect visualization by US. Then, the second stage of treatment is carried out with complete nodule ablation, and the region that was treated first is looked at a second time. From April 2018 to April 2021, nine patients with nine benign nodules were submitted for the iceberg technique. No complications occurred during the entire follow-up period. The patients displayed normal hormonal levels after the procedures, and there was a significant volume reduction of the nodules until three months post-ablation. The iceberg technique is an effective and safe option for the radiofrequency treatment of diving goiters.