Bones, stones and surgical moans: rethinking PTH dynamics in parathyroid surgery
Reviewed by Thomas William Binnersley

Intraoperative parathyroid hormone (IOPTH) testing has revolutionised minimally invasive unilateral parathyroidectomy (MIP) as the gold standard treatment for primary hyperparathyroidism, replacing old-timey four-gland exploration. IOPTH testing ensures reliable excision of all hypersecreting glands, including those pesky hard-to-find ones, without relying solely on visual differentiation. The Miami criteria define operative success by a fall of IOPTH from >50% of baseline within 10 minutes of gland resection. However, Esce and colleagues argue these criteria rely on limited intraoperative kinetic data and small, outdated in vitro studies of parathyroid hormone (PTH) half-life. They decided to evaluate the intraoperative kinetics of PTH to aid surgeons utilising IOPTH monitoring. A prospective cohort of 17 patients with single or double parathyroid adenomas underwent MIP with serial IOPTH monitoring every five minutes from pre-anaesthetic neck examination to wound closure. Levels of IOPTH peaked post-incision but pre-resection. In 8/17 patients this peak occurred during or before skin incision; in 7/17 patients the peak occurred following adenoma manipulation but prior to excision. Interestingly, three-quarters of patients exhibited a significant IOPTH decline prior to gland excision. At excision, half returned to their IOPTH baseline whilst a quarter remained at 150% of their baseline. No patients showed multiple IOPTH spikes. The mean PTH half-life was 5.2 ± 0.4 minutes, longer than previously reported and with considerable interpatient variability. These findings suggest pathologic glands experience a refractory period after releasing their hormonal store. This release does not seem to be triggered by gland resection. Additionally, manipulation of normal glands did not cause IOPTH spikes, indicating possible suppression of healthy glands by the adenoma. More data are required, but these data suggest we may need to rethink current protocols based on the Miami criteria. A better understanding of these dynamics could lead to improved thresholds and timing for assessing success during MIP.

Intraoperative parathyroid hormone kinetics are variable: an in-vivo analysis.
Esce AR, Nicholas RG, Syme NP, et al.
ANN OTOL RHINOL LARYNGOL
2025;134(2):142–7.