An optimal algorithm for intraoperative parathyroid hormone monitoring

A minimally invasive approach to primary hyperparathyroidism is equivalent to bilateral exploration when intraoperative parathyroid hormone (IOPTH) monitoring is used. The optimal strategy for the monitoring has been debated.

There exists an optimal strategy for IOPTH monitoring.

Retrospective study.

Tertiary referral hospital.

A total of 1882 patients underwent parathyroidectomy for primary hyperparathyroidism with IOPTH monitoring. Successful exploration was defined as a 50% or more decline in IOPTH level from baseline and a normal or near-normal IOPTH level at 10 minutes postexcision. These results were compared with those of alternative strategies for IOPTH monitoring, including a 50% decline at 10 minutes, 50% decline at 5 minutes, and normal IOPTH levels at 10 minutes, using the preoperative parathyroid level as baseline.

A curative operation was performed in 1830 patients (97.2%). The current strategy had a sensitivity of 96% and an accuracy of 95%. Multiglandular disease was present in 271 patients (14.5%); 134 of 1858 patients (7.2%) whose outcomes failed to reach curative criteria had confirmed multiglandular disease. Using only a 50% decline from baseline as the curative criterion would result in a failed operation in 22.4% of patients with multiglandular disease. A 50% decline at 10 minutes was 96% sensitive and 94% accurate. A 5-minute value was 79% sensitive and 80% accurate. With use of the 5-minute value, unnecessary bilateral exploration would have been performed in 272 of 1460 patients (18.6%) compared with 62 of 1750 patients (3.5%) when using a 10-minute value. A normal 10-minute value is 91% sensitive and 90% accurate.

A 10-minute postexcision IOPTH level that decreased 50% from baseline and is normal or near normal is highly successful. Relying on a 50% decrease alone increases the rate of operative failure in patients with multiglandular disease.