Efficacy of Topical Anesthesia Before Fine Needle Aspiration of Thyroid Nodule: A Randomized Clinical Trial

Objective: This study aimed to assess the effectiveness of local anesthesia in reducing pain associated with fine needle aspiration (FNA) of thyroid nodules, examine the side effects of local anesthesia, and identify factors that influence pain during FNA of thyroid nodules. Method: We conducted a randomized clinical trial in the Department of Otolaryngology at Ramathibodi Hospital. Patients scheduled to undergo FNA of thyroid nodules were divided into four groups and subsequently administered four types of local anesthesia: Group A (Placebo cream), Group B (Cold placebo cream), Group C (Topical anesthetic cream), and Group D (Cold topical anesthetic cream). The primary outcome was the mean difference in pain levels (measured using a visual analog scale [VAS] and a numeric rating scale [NRS]) between the treatment and control groups. Results: Initially, 72 participants were enrolled in this study, and data from 62 participants were analyzed. The VAS scores were measured at 0, 10, and 30 minutes post-procedure, with mean scores of 25.85 ± 4.65 (Group A), 21.26 ± 4.81 (Group B), 18.05 ± 4.51 (Group C), and 16 ± 4.97 (Group D). Although Group D showed the lowest pain scores, statistical analysis revealed no significant differences between groups (all P > .05). Conclusion: Local anesthesia and cooling can decrease the level of pain. However, in this study, topical anesthetic did not significantly reduce pain compared to non-anesthetic treatments. Level of Evidence: 2.