Intraoperative parathyroid hormone assay: a necessary tool for multiglandular disease.

Objectives: The aims were to: (1) evaluate whether failure of intraoperative parathyroid hormone (ioPTH) to decrease by the Miami criterion is a more specific indicator of multiglandular disease (MGD) than sestamibi scan and (2) determine an adequate cutoff value for decrease in ioPTH in MGD.

Study Design: Case series with chart review.

Setting: Louisiana State University Health Sciences Center- Shreveport.

Subjects And Methods: Review of subjects undergoing parathyroidectomy using ioPTH and sestamibi for suspected parathyroid adenoma between 2005 and 2009. Patients with MGD were identified by pathology and operative reports.

Results: Eighty-three subjects were identified (68 single adenomas, 11 double adenomas, and 4 multiple-gland hyperplasias). Sestamibi predicted MGD in only 4 of 15 cases (27%). Five of the 11 double adenomas (DAs) were identified during initial surgery; the rest required reoperation for cure. ioPTH was useful in predicting MGD in 7 of 10 cases (70%) when a postexcisional value was drawn after removal of the first enlarged gland. Using the Miami criterion of 50% decrease in ioPTH over 15 minutes would have resulted in 1 unnecessary neck exploration and 3 missed DAs. Requiring both a 50% decrease in ioPTH over 15 minutes and normalization of the postexcisional value would have missed only 1 DA and resulted in a single unnecessary neck exploration.

Conclusion: Sestamibi alone fails to identify MGD 73% of the time, but the success rate increases significantly when combined with ioPTH. The “50% and normal” criterion worked best to increase the success rate in our study population, but larger trials are needed to confirm the utility of this criterion.