Objective: Efficacy of eutectic mixture of local anesthetics (EMLA) cream and the needle-free injection of local anesthesia for reducing the pain associated with fine-needle aspiration biopsy (FNAB) of thyroid nodules was previously reported. However, direct comparison of the analgesic efficacy for both methods has not been established yet. The aim of this study was to compare the analgesic efficacy of EMLA cream and needle-free injection of lidocaine for FNAB-associated pain.
Subjects and methods: One hundred and thirty-eight patients having their first ultrasonography-guided thyroid nodule biopsy were allocated to receive either EMLA cream (n=68) or needle-free injection of lidocaine (n=70) 1 h and a few minutes, respectively, before FNAB of thyroid nodules. Patients rated pain associated with the procedure according to a 100-mm visual analog scale (VAS), an 11-point numeric rating scale (NRS), and a 4-category verbal rating scale (VRS).
Results: When the EMLA group was compared with the lidocaine group, there were no significant differences with respect to age, sex, thyroid volume, nodule size, or nodule site. Significant differences were noted in the pain ratings of those 2 groups according to all 3 pain scales. When the effectiveness of EMLA was compared with that of needle-free injection of lidocaine, the mean VAS score was 23.4±20.5 vs 12.7±15.5 mm (P=0.001) and the mean NRS score was 2.8±2.1 vs 1.6±1.7 points (P<0.001). The absolute numbers according to VRS score in each group was also significantly different (P=0.001).
Conclusion: Needle-free injection of lidocaine provides more effective and faster analgesia than EMLA cream application during the FNAB.