Abstract:

Objective To evaluate the association between local anesthesia and procedural pain in patients undergoing fine-needle aspiration （FNA） of thyroid nodules. Methods A total of 207 patients with thyroid nodules who were referred for FNA were prospectively enrolled. Among them， 99 patients received local anesthesia before the procedure， whereas the remaining 108 patients underwent FNA without anesthesia. Pain levels were evaluated using the Numeric Rating Scale （NRS） at two specific time points： immediately after the procedure （within 5 minutes） and during a delayed period （5 - 30 minutes after the procedure）. Linear regression models with robust standard errors and Bonferroni correction were employed for statistical analysis. Results Local anesthesia was associated with a reduction in delayed post-procedural pain NRS at 5 - 30 minutes （β = -0.937， 95%CI： -1.293 - -0.580， adjusted P 0.001）. Older age was associated with less delayed pain （β = -0.01， P = 0.043）， and a longer puncture duration was associated with higher pain scores during this time frame （β = 0.07， P = 0.007）. The association between local anesthesia and immediate post-procedural pain （within 5 minutes） did not reach statistical significance after Bonferroni correction （adjusted P = 0.046； Bonferroni-corrected α = 0.025）. Conclusion Local anesthesia was associated with a reduction in delayed pain （5 - 30 minutes） after thyroid FNA， but not with immediate pain （ 5 minutes）.

Key words: local anesthesia, post-procedural pain, fine-needle aspiration biopsy, thyroid nodules