Sestamibi Scan–directed Parathyroid Surgery: Potentially High Failure Rate without Measurement of Intraoperative Parathyroid Hormone

The present study evaluated sestamibi scan–directed parathyroidectomy with intraoperative parathyroid hormone (PTH) assessment (ioPTH). The preoperative sestamibi scintigraphies were compared with the intraoperative findings for 103 patients undergoing first exploration for sporadic primary hyperparathyroidism (pHPT). Data were collected prospectively. Ninety-nine patients (96%) were cured. Patients with persistent pHPT (n = 4) all had an incorrect scintigram as well as an insufficient decline of ioPTH. At operation, 90 patients (87%) had solitary parathyroid adenoma; 12 patients had multiglandular disease. In one patient no enlarged parathyroid gland was found. Overall 77 of 118 abnormal glands (65%) were correctly identified by sestamibi scintigraphy. The sensitivity for localizing a single parathyroid adenoma was 80%. Patients with incorrect scintigrams had a higher proportion of upper pole adenomas than patients with correct scans. High glandular weight and high level of serum PTH were important factors for detectability. Sestamibi scintigraphy did not predict multiglandular disease. However, the use of ioPTH identified 8 of the 9 patients with a positive scan (a solitary focus) and multiglandular disease. In contrast, false-negative ioPTH led to four unnecessary bilateral explorations in the 63 patients with a scan-identified adenoma. With the help of ioPTH, a focused parathyroidectomy was accomplished in 43% of scan-negative patients with a solitary adenoma. In conclusion, sestamibi scintigraphy is an acceptable method for localizing a solitary parathyroid adenoma. However, the technique alone does not reliably predict multiglandular disease. Potentially the failure rate in scan-directed parathyroidectomy could increase, with up to 10% of patients without ioPTH.