Needle-free delivery of lidocaine for reducing the pain associated with the fine-needle aspiration biopsy of thyroid nodules: Time-saving and efficacious procedure

Objective: Fine-needle aspiration biopsy (FNAB) is a mandatory procedure in evaluation of thyroid nodules. However, it is sometimes perceived as a painful procedure by the patients. Efficacy of the needle-free injection of local anesthesia for reducing the pain associated with other cutaneous procedures that involve needle insertion was previously reported. In this double-blind, placebo-controlled clinical trial, we evaluated the effectiveness of a needle-free injection of lidocaine in achieving satisfactory pain control in patients undergoing FNAB of thyroid nodules. Design: Patients were allocated to receive either lidocaine administered by needle-free injection system (n = 55) or placebo ( isotonic saline) (n = 52) 2 - 3 minutes before FNAB. A series of four aspirations of each nodule was performed. The 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 four-category verbal rating scale (VRS). Main outcome measure: The two groups studied were similar with respect to age, sex, thyroid volume, nodule size, and nodule site. When the effectiveness of lidocaine was compared with that of placebo, the mean VAS score was 11.4 +/- 13.6mm versus 38.2 +/- 35.5mm ( p < 0.0001) and the mean NRS score was 1.4 +/- 1.5 points versus 3.9 +/- 2.6 points ( p < 0.0001), respectively. The absolute numbers according to VRS score in each group was also significantly different ( p < 0.0001). The percentage of patients with "no pain'' or "mild pain'' in the lidocaine group (90.9%) was significantly higher than that in the placebo group (44.2%) ( p < 0.0001). Less than 10% of the patients in lidocaine group experienced moderate pain and none experienced severe pain. No adverse treatment-related effects were observed. Conclusions: To our knowledge, this is the first study demonstrating that the needle-free delivery of lidocaine is an effective, useful, and noninvasive method of providing local anesthesia for the FNAB of thyroid nodules.