Applicability of rapid intraoperative parathyroid hormone assay through fine needle aspiration to identify parathyroid tissue in thyroid surgery

Abstract

Hypoparathyroidism is a frequent and serious complication of thyroid surgery. Identification and preservation of the parathyroid glands are key factors in managing hypoparathyroidism. The aim of the present study was to investigate the efficacy of rapid intraoperative parathyroid hormone (rIO-PTH) assay levels through fine needle aspiration (FNA) in identifying parathyroids as a parameter in thyroid surgery. rIO-PTH assay through FNA and frozen section examination were performed on 194 suspected parathyroids anatomical structures from 50 consecutive patients undergoing thyroidectomy (rIO-PTH group). The association between the rIO-PTH values and histological results were analyzed. Clinical effects were compared between the rIO-PTH and control groups from 50 patients undergoing a similar standard surgery. rIO-PTH levels from 93/194 aspirated anatomical structures certified as parathyroid tissues by histological analysis were demonstrated to have a mean of 3,369 pg/ml (range, 145.2-5,000 pg/ml). These values were significantly increased compared with the mean value of 25.7 pg/ml from non-parathyroids tissues significantly (P<0.001). The mean number of 3.76 on the recognized parathyroids was obtained by naked eye measurements combined with rIO-PTH assay through FNA, was significantly higher than compared with only naked eye measurements (P<0.05). Postoperative permanent or transient hypoparathyroidism was not detected in the rIO-PTH groups. The difference between the postoperative serum calcium level and blood PTH values of rIO-PTH and control groups was not statistically significant (P>0.05). The value of rIO-PTH assay through FNA demonstrated that it is a good parameter for differentiating parathyroids and non-parathyroids tissues. The technique is a highly reliable, quick, simple and non-invasive method with a short learning curve in thyroid surgery, which is particularly valuable for inexperienced surgeons. This method may replace frozen section examination, which relies on a surgeon's personal experience on the basis of topographic or morphologic criteria for recognizing parathyroids.