Operative monitoring of parathyroid gland hyperfunction.

With a 20-year experience of more than 700 parathyroidectomies, our persistent hypercalcemic postoperative failure rate of 7% has remained constant. Reasons for failure have been misdiagnosis or inability of the surgeon to detect and excise all hypersecreting glands. We have modified a commercially available immunoradiometric assay for intact parathyroid hormone (PTH) resulting in a 15-minute turnaround time. Since intact PTH has a half-life measured in minutes, whole blood samples taken 10 minutes after gland excisions were monitored intraoperatively to confirm significant changes in circulating hormone. Quantitative evidence that all hyperfunctioning parathyroid tissue had been ablated during operation was obtained in 19 of 21 patients. Less than four glands each were identified in 53% of these patients. The PTH "quick" test correctly pointed to an inadequate excision requiring further parathyroid ablation in two patients, made bilateral neck exploration unnecessary in two patients who had previously undergone parathyroidectomy, and predicted persistent hypercalcemia in two patients with complications.