The Analgesic Efficacy of Lidocaine/Prilocaine Cream during Fine-needle Aspiration Biopsy of Thyroid Nodules: A Randomized Double-blind Clinical Trial

Abstract

Introduction: Fine-needle aspiration biopsy (FNAB) method is an effective method in diagnosis and approach to patients with thyroid nodules that create pain. This study investigates the analgesic effect of lidocaine/prilocaine cream during fine-needle aspiration (FNA) of thyroid nodules to reduce discomfort in patients during the procedure. Materials and Methods: In a double-blind clinical trial, two groups including patients with thyroid nodules who were rubbed with lidocaine + prilocaine 5% on their skin before FNA and patients with thyroid nodules, who have had topical placebo cream applied to their skin before FNA, were recruited. The Numerical Rating Scale was used to check the pain level. The Chi-square test, Fisher’s exact test, independent t-test, and Mann–Whitney’s nonparametric test were used for data analysis in SPSS software. Results: The average pain sensation in the intervention group is lower than the scores obtained in the control group, but despite the existing difference, this difference was not statistically significant (P = 0.7). The investigations showed that with the increase in the size and diameter of the thyroid nodules, the amount of pain that the patient feels during the procedure is reduced. Moreover, increasing the size of the nodule significantly reduces the amount of pain felt by the patient in the intervention group (P = 0.04). Conclusion: The results of this study indicated that the use of lidocaine/prilocaine cream in patients who are candidates for thyroid nodule biopsy did not have a significant effect on reducing their pain in contrast with literature. Therefore, based on the findings of the study, the use of lidocaine/prilocaine cream in these patients does not offer any significant decrease in pain sensation compared to using just a placebo.