Li-Jen Liao, Wu-Chia Lo, Wan-Lun Hsu, Po-Wen Cheng, Cheng-Ping Wang

The aim of this study was to evaluate pain scores and specimen adequacy for ultrasound-guided fine-needle aspiration biopsy (US-FNAB) of thyroid nodules without and with local anesthesia (LA). The US-FNAB procedure was performed on 183 patients with and without LA. One puncture was made for solid nodules, and if patients could tolerate it, a two-puncture technique was used for nodules with a cystic change. Four-point verbal rating scores were assessed by a nursing assistant after completion of US-FNAB. To be an adequate specimen, at least six groups of follicular cells are required, and each group should contain at least 10 cells. Immediately after US-FNAB, 92% of patients with LA and 80% without LA reported no or mild pain (p=0.01). Most patients tolerated the procedure well, with no pain (82.5%) reported 5 minutes after the procedure. In univariate logistic regression, irregular boundary (odds ratio [OR]: 2.52, 95% confidence interval [CI]: 1.04-6.06, p=0.04), calcification (OR: 2.86, 95% CI: 1.06-7.76, p=0.04), and LA (OR: 0.35, 95% CI: 0.15-0.86, p=0.02) were significantly associated with immediate moderate or severe pain. Specimen adequacy was significantly associated with age (OR: 0.95, 95% CI: 0.92-0.97, p<0.01), heterogeneous echo-texture (OR: 1.76, 95% CI: 1.23-5.17, p=0.01), predominate solid architecture (OR: 2.78, 95% CI: 1.42-5.41, p<0.01), and the use of LA (OR: 3.34, 95% CI: 1.70-6.56, p<0.01). In multivariate logistic regression, patients receiving LA had lower risk of moderate or severe pain (OR: 0.25, 95% CI: 0.09-0.67, p=0.01) and higher chances of specimen adequacy (OR: 4.84, 95% CI: 2.17-10.7, p<0.01) compared to patients who did not receive LA. US-FNAB is a safe procedure, and most patients report no pain 5 minutes after the procedure. The use of LA was associated with lower immediate pain scales and higher specimen adequacy.