BACKGROUND: Fine-needle biopsy is the international standard for diagnostic evaluation of thyroid nodules. There is a lack of consensus regarding the optimal needle biopsy technique. The implementation of capillary action versus aspiration and the optimal needle gauge remain topics of debate. METHODS: A systematic review of the Medline, Embase, and Cochrane databases was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Articles evaluating the effects of capillary action versus aspiration and needle gauge on success rates of fine-needle biopsy of the thyroid were assessed for inclusion. The primary outcome of interest was the rate of non-diagnostic cytopathology. RESULTS: Twenty-four articles with a collective 4428 nodules were ultimately included in the review. Twenty articles evaluated capillary action versus aspiration, and six evaluated needle gauge. All but two studies were prospective, most of which were blinded trials with or without randomization. Using a random-effects model, capillary action was associated with a statistically significant reduction in the relative risk of non-diagnostic cytopathology (relative risk = 0.57 [confidence interval 0.34-0.92]; p = 0.02). There was a nonsignificant trend in favor of smaller needle gauges. CONCLUSION: Given the statistically significant deceased rate of non-diagnostic cytopathology with capillary action and the potential for increased pain and complications with larger needles without a proven benefit, needle biopsy of routine thyroid nodules should be performed without aspiration and with smaller needle gauges (24-27G).
BACKGROUND: Fine-needle biopsy is the international standard for diagnostic evaluation of thyroid nodules. There is a lack of consensus regarding the optimal needle biopsy technique. The implementation of capillary action versus aspiration and the optimal needle gauge remain topics of debate. METHODS: A systematic review of the Medline, Embase, and Cochrane databases was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Articles evaluating the effects of capillary action versus aspiration and needle gauge on success rates of fine-needle biopsy of the thyroid were assessed for inclusion. The primary outcome of interest was the rate of non-diagnostic cytopathology. RESULTS: Twenty-four articles with a collective 4428 nodules were ultimately included in the review. Twenty articles evaluated capillary action versus aspiration, and six evaluated needle gauge. All but two studies were prospective, most of which were blinded trials with or without randomization. Using a random-effects model, capillary action was associated with a statistically significant reduction in the relative risk of non-diagnostic cytopathology (relative risk = 0.57 [confidence interval 0.34-0.92]; p = 0.02). There was a nonsignificant trend in favor of smaller needle gauges. CONCLUSION: Given the statistically significant deceased rate of non-diagnostic cytopathology with capillary action and the potential for increased pain and complications with larger needles without a proven benefit, needle biopsy of routine thyroid nodules should be performed without aspiration and with smaller needle gauges (24-27G).