Assessment of the effectiveness of local anesthesia before thyroid fine needle biopsy considering the size of the nodule

Background: Fine needle aspiration biopsy (FNAB) is usually used to distinguish the malignant and benign nodules. Applying a biopsy needle evokes a sense of fear and pain in the patients. Although some studies refute the usefulness of local anesthesia (LA) prior to fine needle aspiration biopsy, it is still debatable. This prospective cross-sectional study intended to evaluate the effect of LA prior to fine needle aspiration biopsy on pain and anxiety considering nodule size. Methods: Amongst the patients who were referred to Shiraz Shahid Fagihi Hospital for Thyroid fine needle aspiration biopsy from August 2017 to January 2018, 114 patients participated in this study. LA was performed for 41 patients, and 73 underwent the thyroid nodule fine needle aspiration biopsy without LA. Patients' pain and anxiety were scored using the visual-analog-score and Spielberger anxiety scale. The nodules were categorized into five groups. Pain and anxiety of patients were compared considering their nodule sizes to assess the effects of LA in the reduction of pain and anxiety considering the nodule size. Results: The patients undergoing LA had a mean age of 44.69 years old and average body mass index (BMI) of 26.7, the patients who performed thyroid nodule fine needle aspiration biopsy without LA had a mean age of 48.17 years old with an average BMI of 26.0. The patients with the maximum nodule size of<10 mm, experienced more pain during the fine needle aspiration biopsy without LA, but there was no significant difference between the S/T-anxiety of these patients. There was no significant difference between the pain and anxiety scores of the patients with larger nodules. Conclusion: The more pain experienced by the patients with the smallest nodules can be attributed to the need for more needle manipulation due to the small nodule size and less precision while piercing the needle into the nodule. Thus, it can be suggested that in patients with a small nodule size, less than 10mm, usage of LA prior to fine needle aspiration biopsy can reduce the pain significantly.