Accuracy of Preoperative localization studies and intraoperative parathyroid hormone assay in patients with primary hyperparathyroidism and double adenoma

BACKGROUND: The purpose of this retrospective investigation was to evaluate the results of preoperative localization studies and intraoperative parathyroid hormone (IOPTH) assay in patients with primary hyperparathyroidism and double adenomas. STUDY DESIGN: Twenty-one of 287 consecutive patients with primary hyperparathyroidism who had double adenomas identified during first-time parathyroid exploration between July 1999 and September 2002 were analyzed. Individual and combined accuracy of preoperative localization studies, and IOPTH assay and their influence on surgical strategy, were compared. RESULTS: Seven percent of these 287 patients had double adenomas. Fifteen of the patients were female and six were male with a mean age of 59 years (range 17 to 76 years). The accuracy of ultrasonography (US) and technetium 99m sestamibi ((TC)-T-99m-sestamibi) was 40% and 30%, respectively, in this select group. Combined accuracy of both tests reached 60% and guided the surgeon to select a bilateral approach. After removal of the first gland, IOPTH failed to decrease by 50% relative to the highest baseline value in 43% of the cases, indicating other hyperfunctioning parathyroid glands. These results prompted the surgeon to explore further after an initially planned focused approach. When the combination of three tests was analyzed, at least one test accurately suggested a double adenoma in 80% of the patients; in 15% of the patients, no test was suggestive of a double adenoma and in 5% the sestamibi scan was false positive. CONCLUSIONS: This retrospective investigation documents that neither preoperative localization tests nor IOPTH assay accurately document double adenomas in patients with primary hyperparathyroidism. The combined accuracy of US, sestamibi, and IOPTH assay predicted a double adenoma in 80% of the patients.