Comparison of quick parathyroid assay for uniglandular and multiglandular parathyroid disease.

Background: The quick intraoperative parathyroid assay (qPTH) has been proposed as an effective tool in the surgical management of hyperparathyroidism. This assay may facilitate directed, unilateral exploration for uniglandular disease; however, its role in the management of multiglandular disease remains unclear. The purpose of this study is to evaluate the use of qPTH in parathyroid surgery, and to compare the results for uniglandular and multiglandular disease.

Methods: A prospective analysis of 63 consecutive patients explored for hyperparathyroidism using the qPTH assay was performed. Preoperative localization studies including ultrasonography and sestamibi scan were routinely obtained. Blood samples for qPTH were routinely drawn prior to the surgical incision, prior to gland excision, as well as 5 and 10 minutes after gland excision. Patients with primary or secondary hyperplasia had blood samples drawn relative to a 3-1/2 gland resection. Additional samples were drawn as needed for patients with a double adenoma. A qPTH decline of greater than or equal to 50% of the highest preincision or gland preexcision level was considered successful. Unilateral neck exploration was routinely performed unless multiglandular disease was identified. Patients were followed up postoperatively with serum calcium levels and an 8-month median follow-up was recorded.

Results: Forty-nine of 63 (78%) patients were found to have a solitary parathyroid adenoma. The qPTH assay was successful in 48 (97%) patients with uniglandular disease. Forty-four of these 48 patients showed an appropriate assay decline 5 minutes after adenoma excision. One patient with a single adenoma showed a delayed 50% decline in qPTH at 20 minutes. Fourteen (22%) patients were found to have multiglandular disease: 6 patients with primary hyperplasia, 4 patients with hyperplasia secondary to renal failure, and 4 patients with double adenomas. All patients with multiglandular disease demonstrated a successful decrease in qPTH levels. All patients with hyperplasia secondary to renal failure showed a successful assay decline 5 minutes after 3-1/2 gland resection. Eight of 14 (57%) patients with multiglandular disease (4 double adenomas, and 4 hyperplasia) were suspected to have solitary adenomas preoperatively. Overall, 62 of 63 (98%) patients showed an appropriate assay decline within 10 minutes after gland excision. Postoperatively, all patients were normocalcemic with a median follow-up of 8 months.

Conclusions: These data suggest that qPTH can accurately facilitate unilateral, directed neck exploration for uniglandular parathyroid disease, as well as guide the extent of gland resection for multiglandular disease. This assay reliably eliminates the most common cause of parathyroidectomy failure, which is unrecognized multiglandular disease. The qPTH assay can reliably be used with similar accuracy for patients with multiglandular disease as has been shown for uniglandular parathyroid disease.