Intraoperative measurement of parathyroid hormone in minimally invasive surgery for parathyroid adenoma.

INTRODUCTION: In the past bilateral neck exploration was the gold standard for successful surgical management of primary hyperparathyroidism. More restricted procedures have been introduced recently thanks to imaging techniques and intraoperative parathyroid hormone assay confirming eradication of hyperfunctioning tissue.

METHODS: Thirty patients operated for parathyroid adenoma were submitted to intraoperative PTH determination with Quick Pack immunochemiluminescent assay (Nichols lab.) prior to excision and 5, 10 and 20 minutes after removal of the presumed hyperactive gland. Eleven patients were operated on by a minimally invasive procedure with videoassistance.

RESULTS: Response to excision of the hyperfunctioning gland was evidenced by a significant decrease of PTH levels (50% of initial value) in 26 patients. Plasma PTH levels decreased by at least 80% of pre-excisional value after 20 minutes, 70% after 10 minutes and by 50% after 5 minutes. In 2 cases, significant decrease of PTH was obtained after 45 and 60 minutes respectively. In 2 other cases, the adenoma could not be found and there was no decrease of PTH even after extensive exploration of the neck. In the 11 patients who underwent minimal invasive surgery, 2 were converted to open neck surgery: in one case the adenoma was not accessible in the upper part of the neck, in the other case the hyperfunctioning gland remained undiscovered.

CONCLUSION: intraoperative measurement of PTH should be considered a reliable and reproducible method for evaluation of the secreting activity of a parathyroid gland. The Quick Pack method has the advantage of confirming that the hyperactive gland has really been eradicated and consequently of considerably reducing operating time and avoiding extensive exploration of the neck.