Abstract: Objective To assess the safety and efficacy of“leverage pry-off method”for preventing thermal injury during microwave ablation of benign thyroid nodules. Methods From July, 2017 to September, 2019, a total of 348 patients with benign thyroid nodules underwent ultrasound-guided microwave ablation. For protecting from thermal injury during the ablation, "hydrodissection technique" was used in 174 of the patients (admitted from July, 2017 to August, 2018) and "leverage pry-off method" in the other 174 patients (admitted from September, 2018 to September, 2019). All the patients were followed up for 1 to 12 months after the operation for observation of severe complications and nodular residues. Results Ultrasound- guided microwave ablation was completed in all the 348 patients. The most common severe complication associated with the ablation was voice change, occurring in 3 cases (1.7% ) in "hydrodissection technique" group and in 4 (2.3% ) in the "leverage pry-off method" group, showing no significant difference between the two groups (P>0.05). During the follow-up, no significant difference was found in the rate of nodular residues between the "hydrodissection technique" group and "hydrodissection technique" group (9.8% vs 10.9% (P>0.05). Conclusions The "leverage pry-off method" is simple and effective for preventing thermal injury during microwave ablation of benign thyroid nodules.

Key words: hydrodissection; leverage pry-off; ultrasound-guided; microwave ablation; benign thyroid nodules