Value of intraoperative parathyroid hormone monitoring

Background: Routine use of intraoperative parathyroid hormone (IOPTH) has been challenged in both unilateral/limited (LE) and bilateral exploration (BE). To investigate this, we assessed the usefulness of IOPTH in surgical management of primary hyperparathyroidism and parathyroid carcinoma (PC). Methods: Between 1998 and 2006, 1133 patients were explored for hyperparathyroidism: 185 LE, 743 BE with IOPTH, 95 BE without IOPTH, 110 reoperations, and 4 PCs. IOPTH patterns were correlated with parathyroid pathology (single adenoma [SA] or multigland disease [MGD]) and operative success. Results: In LE, IOPTH returned to normal in 78% of patients; all patients had SA, and 99% were cured at a mean +/- SEM of 1.2 +/- .24 years; 22% of LE patients (n = 41) whose IOPTH did not return to normal were converted to BE, and all had MGD. BE with and without IOPTH was equally successful 97% and 98% (P = NS) of the time, respectively. In BE in which IOPTH did not return to normal, 9% of patients remained hypercalcemic; tumor distribution mirrored other BE patients (75% SA, 25% MGD). In reoperations, a normal final IOPTH correlated with cure in 99%; otherwise, 59% had persistent disease. Differential bilateral internal jugular vein IOPTH sampling lateralized disease in 77% of reoperations. Conclusions: IOPTH is an important adjunct for successful LE by identifying the presence of MGD and avoiding operative failure. IOPTH adds little to BE; however, final IOPTH values may predict persistent disease in BE, reoperations, and PCs.