Additional 20-Minute Intraoperative Parathormone Measurement Can Minimize Unnecessary Bilateral Neck Exploration

Parathyroidectomy guided by intraoperative parathormone (ioPTH) monitoring for primary hyperparathyroidism (pHPT) confirms removal of all hyperfunctioning parathyroid glands. This study evaluates the utility of an additional 20-min ioPTH measurement in patients who fail to meet the >50% ioPTH drop criterion.

A retrospective review of prospectively collected data of 706 patients with pHPT who underwent parathyroidectomy guided by ioPTH monitoring was performed. When a >50% ioPTH decrease from the highest either preincision or preexcision level was achieved after 10 min, parathyroidectomy was completed. If this criterion was not met, further exploration was performed or an additional 20-min ioPTH measurement was obtained.

Of 706 patients, 72 (10%) patients did not meet the >50% ioPTH drop criterion at 10 min. Of these patients, 67% (48/72) underwent immediate bilateral neck exploration (BNE). For the other 33% of patients (24/72), a 20-min parathormone (PTH) measurement was drawn. Of patients with an additional 20-min PTH measurement, 46% (11/24) had a >50% ioPTH decrease at 20 min where BNE was avoided and parathyroidectomy completed, whereas 54% (13/24) did not. Compared to patients with insufficient ioPTH drop at 10 min and subsequent BNE, there was a statistically significant 46% reduction of BNE in patients with a 20-min PTH level (P < 0.01).

A 20-min ioPTH measurement is useful in preventing unnecessary BNE in some patients who undergo focused parathyroidectomy with a delayed >50% ioPTH drop.