Can the outpatient parathormone value be used instead of the initial value in intraoperative parathormone measurement during primary hyperparathyroidism surgery?

Intraoperative parathyroid hormone (IOPTH) measurement is widely used to confirm surgical success in primary hyperparathyroidism (PHPT). The Miami criterion is the most widely used. Despite the significant advantages of IOPTH, its cost remains a matter of debate. This study aimed to investigate the necessity of pre-excision parathyroid hormone (PTH) measurement during parathyroidectomy in PHPT patients. The files of 159 patients who underwent parathyroidectomy in our department between January 2022 and December 2023 were retrospectively reviewed. Patients aged 18 years and older who underwent parathyroidectomy for PHPT were included. Patients with secondary/tertiary hyperparathyroidism and those with incomplete data were excluded. PTH levels were measured in all patients at the outpatient clinic (OPC-PTH), before incision [pre-incision IOPTH (IOPTH1)] and 10 min after pathologic gland(s) excision [post-excision IOPTH (IOPTH2)] intraoperatively. OPC-PTH/IOPTH2 and IOPTH1/IOPTH2 results were compared, and a decrease of > 50% was considered a successful excision. Cure is defined as postoperative normocalcemia. A total of 122 patients who met the study criteria were included. The median age was 55 years (20-80 years). One hundred and three patients (84.4%) were female. A total of 3 (2.5%) patients had persistent disease. The accuracy rates for OPC-PTH/IOPTH2 and IOPTH1/IOPTH2 for cure prediction were 91% and 93.4% respectively, and no statistically significant difference was found between methods (p = 0.474). Evaluating outpatient PTH levels with post-excision PTH levels can be used to confirm surgical success with high accuracy. Using this method can offer advantages in terms of both operative time and cost.