A Literature Review of Factors Associated With Pain From Fine Needle Aspiration Biopsy of Thyroid Nodules

ObjectiveThyroid nodules are common, being detected in 19% to 67% of the population. A fine needle aspiration biopsy (FNAB) is recommended for suspicious thyroid nodules to rule out malignancy; however, the procedure can be painful for subsets of patients. It remains unclear what factors are more likely to be associated with pain during FNAB. This literature review aimed to investigate patient-, procedure-, and analgesic-related factors that affect pain levels during thyroid nodule FNAB.MethodsPredefined inclusion and exclusion criteria were set to search the Embase, MEDLINE, CINAHL, and Cochrane databases. The articles evaluating the factors affecting pain during FNAB were assessed for inclusion. The primary outcome of interest was scores evaluating pain level during FNAB.ResultsTwenty-two studies were included. The studies were a mix of cohort studies, randomized controlled trials, and clinical controlled trials. Under patient-related factor, nodule calcification was associated with increasing pain. The procedure-related factors potentially increasing pain included the number of needle passes and utilization of the aspiration technique (as opposed to capillary action), perpendicular needle placement (as opposed to parallel), and not using safety devices. Larger needle size, type of biopsy, operator expertise, and patient education did not appear to be correlated with pain. Subcutaneous lidocaine appeared to provide better pain relief than a topical analgesic.ConclusionWith increasing use of FNAB as the diagnostic test of choice for assessing thyroid nodules, understanding patient-, procedure-, and analgesic-related factors associated with optimal patient satisfaction is imperative.