Research Mentor Name

Dr. Michael Singer

Research Mentor Email Address

Institution / Department

Henry Ford Hospital, Department of Otolaryngology - Head and Neck Surgery

Document Type

Research Abstract

Research Type


Level of Research



Background: A subset of patients with primary hyperparathyroidism present with inappropriately normal PTH levels despite elevated serum calcium, called normohormonal primary hyperparathyroidism (NHPHP). This disease variant presents a clinical dilemma regarding intraoperative parathyroid hormone (IOPTH) monitoring during parathyroidectomy when using the standard criteria of a ≥ 50% reduction in IOPTH from baseline to determine surgical success. This study aimed to determine what percent reduction in post-excision IOPTH from baseline in NHPHP patients would yield a high cure rate similar to that of classic primary hyperparathyroidism.

Methods: This was a single surgeon, single institution retrospective cohort study of patients that underwent parathyroidectomy between July 2013 and February 2020. Demographic, preoperative, intraoperative, and postoperative metrics were collected. Patients with NHPHP were compared to those with classic primary hyperparathyroidism.

Results: 496 patients were included in the study. 66 (13.3%) were of the normohormonal variant based on preoperative intact PTH levels and 28 (5.6%) based on baseline IOPTH levels. The cure rates in the normohormonal groups were not significantly different from their classic counterparts: 98.4% and 100.0% vs 97.1% and 97.1%, p = 1.000. The median percent decline in post-excision IOPTH from baseline that achieved cure in the normohormonal groups were 82.8% and 80.4% compared to their respective controls of 87.3% and 87.1%, p = 0.017 and p=0.001.

Conclusion: A ≥ 75% decline in 15-minute post-excision IOPTH level from baseline can be used as a more stringent criterion for achieving high rates of cure in patients with NHPHP that undergo parathyroidectomy.


Medicine and Health Sciences