The importance of subcapsular anesthesia in the anesthesiological management for thyroid radiofrequency ablation.

Radiofrequency ablation is a minimally invasive procedure alternative to surgery to treat benign thyroid nodules causing compressive symptoms. Tolerability of this procedure, aimed at treatment of benign conditions, is fundamental. In this study, we evaluated if local anesthesia should be enough to reduce both hospital costs and sedation-related risks for the patient, avoiding deep sedation and presence of the anesthesiologist. From July 2017 to August 2018, 14 consecutive patients (mean age 60.1 years) were treated and divided in two groups: Group A (7 patients) underwent systemic sedoanalgesia (intravenous remifentanil/fentanyl ± intravenous midazolam ± intravenous acetaminophen/nonsteroidal anti-inflammatory drugs) + subcutaneous anesthesia (lidocaine), with anesthesiologist. Group B (7 patients) underwent mild systemic sedoanalgesia (oral solution morphine sulfate + intravenous midazolam + intravenous acetaminophen) + both subcutaneous and subcapsular anesthesia (mepivacaine + bupivacaine), without anesthesiologist. Tolerability, sedation grade (Ramsay scale), total opioid dose, complications, and results at 12 months were analyzed and compared. Mean tolerability was 9.4 in group A and 8.9 in group B (p: 0.786). Mean sedation grade was 3.86 in group A and 2.71 in group B (p: 0.016). Mean total opioid dose was 70.9 mg in group A and 10 mg in group B (p:0.00015). No complications were observed. At 12 months, mean volume reduction was 56.1% in the group A and 60% in the group B. In thyroid radiofrequency ablation, subcapsular anesthesia can decrease both total opioid dose and level of patient's sedation without significant differences in tolerability, allowing to perform ablation without the anesthesiologist.