Intraoperative parathyroid hormone as an indicator for parathyroid gland preservation in thyroid surgery

Abstract

BACKGROUND: Intra-operative parathyroid hormone (PTH) levels have successfully been used to assess surgical ablation of parathyroid adenomas, the use of this same test to predict preservation of viable gland has not been widely used. AIM: to test the sensitivity and specificity of intraoperative rapid PTH assay test in predicting permanent postoperative hypoparathyroidism, and applicability to guide the search for inadvertently removed parathyroid glands for possible auto transplantation. PATIENTS AND METHODS: 52 patients undergoing total thyroidectomy for non-malignant thyroid diseases were included. Intraoperative rapid PTH assay test was performed. If levels were reduced, or less than 3 parathyroid glands were detected, removed thyroid gland was examined for unintentionally removed parathyroid tissue for possible auto transplantation. RESULTS: There was a strong correlation between intraoperative rapid PTH assays and those taken 24 hours after surgery, 16 out of 52 patients had reduction of the PTH intraoperatively to levels below 25 pg/ml, of them, 11 patients (who had values between 15–24 pg/ml) recovered to normal PTH levels within 4 weeks, while the 5 patients with intraoperative PTH levels below 15 pg/ml failed to regain normal PTH levels up to 12 weeks postoperatively, even in those patients where parathyroid tissue was auto transplantated. The 4 patients who had parathyroid tissue reimplanted intraoperatively restored some of their parathyroid function as indicated by relative rise of their PTH levels, but did not reach even the low normal levels. (ROC) curve for prediction of early hypoparathyroidism using intraoperative rapid PTH assay was statistically highly significant with optimal cutoff value for predicting early hypocalcaemia level 80% F/U).

Keywords

• parathyroid
• parathyroid hormone assay
• thyroidectomy