Intraoperative parathyroid hormone assay in patients with primary hyperparathyroidism and double adenoma.
OBJECTIVE
To determine the utility of parathyroid hormone (PTH) monitoring for double adenomas (DAs).


DESIGN
Retrospective chart review.


SETTING
Tertiary referral center.


PATIENTS
The study included 47 patients with primary hyperparathyroidism who had DAs identified during first-time parathyroid exploration.


MAIN OUTCOME MEASURES
Intraoperative PTH levels were measured in every case, and the intraoperative PTH assay and its influence on surgical outcome were examined.


RESULTS
A total of 47 of 552 consecutive patients (8.5%) with primary hyperparathyroidism were found to have DAs; 457 patients (82.7%) had single adenomas; and 48 patients (8.6%) had disease in more than 2 glands. The mean (SD) age of the patients with DAs was 58 (14) years, and 26 patients (55%) were female. The mean (SD) preoperative intact PTH level was 129 (57) pg/mL (to convert to nanograms per liter, multiply by 1), and the preoperative serum calcium level was 11.0 (0.6) mg/dL (to convert to millimoles per liter, multiply by 0.25). In all patients, the intraoperative PTH levels decreased by 79.7% (11.4%) from baseline after removal of both abnormal parathyroid glands. When the location could be confirmed, the second adenoma was ipsilateral in 17 patients (36%) and contralateral in 27 patients (64%). The mean (SD) postoperative intact PTH level was 46 (26) pg/mL at 6 months, and the cure rate was 98%.


CONCLUSIONS
Intraoperative PTH monitoring and maintenance of normocalcemia after surgery confirm previous reports that DAs do exist and are not simply missed cases of 4-gland hyperplasia. Intraoperative PTH monitoring accurately predicted the success of parathyroidectomy in 98% of patients with DAs.