Effects of Regional and General Anesthesia on the Therapeutic Outcome of Benign Thyroid Nodules Treated with High Intensity Focused Ultrasound (HIFU)

Abstract

Background The study investigated whether anesthesia performed during high-intensity-focused-ultrasound treatment (HIFU) of benign thyroid nodules influenced the therapy outcome, based on volume reduction and the amount of energy delivered. Methods Thirty patients with benign thyroid nodules were treated with HIFU under general or regional anesthesia at two centers from 2014 to 2019. During HIFU, a therapeutic ultrasound probe, EchoPulse (Teraclion, Malakoff, France), heats the focus to 80–90 degrees Celsius. Nodal volumes were measured by ultrasound before and 3 months after therapy. For statistical analysis, the total population was divided into two groups according to the anesthesia performed. In a retrospective long-term multicenter study, volume reduction and the energy delivered were analyzed using the Wilcoxon signed-rank test and the Mann–Whitney test. Results At three months follow-up, the total study population had an average volume reduction of 39.26% (range 4.03–91.16%, p < 0.001, n = 30), the general anesthesia group of 47.46% (range 13.64–91.16%, p = 0.001, n = 15) and the regional anesthesia group of 31.06% (range 4.03—68.63%, p = 0.001, n = 15). Under regional anesthesia a median energy of 3.16 kJ/cm3 (range: 0.96 – 8.2 kJ/cm3) and under general anesthesia a median energy of 0.88 kJ/cm3 (range: 0.18 – 1.63 kJ/cm3) were delivered. All results were significant with p < 0.05. The complication rate was 6.67%. Conclusion HIFU is an effective method to treat benign thyroid nodules. Comparing anesthesia methods, volume reduction is higher in patients treated under general anesthesia and less energy has to be delivered under general anesthesia.