A new approach for perioperative parathyroid hormone (PTH) measurement to establish cure in patients with primary hyperparathyroidism

In this study, we analyse the possibility to omit pre-incision PTH measurement since we routinely measure it at the time of pre-surgery ambulatory admission.

A total of 435 patients were enrolled. All patients with pHPT included underwent pre-surgical PTH level assessment as part of the pre-admission preparation to surgery. Intraoperative PTH was routinely assessed after induction of the anaesthesia (pre-incision PTH) and 15 min after resection of the enlarged gland(s) (post-excision PTH). Moreover, calcium and PTH levels were routinely assessed on the first postoperative day. Cure was defined as an intraoperative drop of > 50% or into normal range on first post-operative day.

The median value of the preoperative and pre-incision PTH were both 127 pg/ml (p = ns). Thirty-two patients (7.3%) exhibited a not appropriate drop of post-excision PTH level. Nevertheless, nineteen of them (59.3%) showed a satisfying PTH drop on 1st POD. Ten patients (2.3%) experienced a persistent disease with six achieving cure through reoperation. Additionally, three patients (0.6%) showed normalization of calcium and PTH values during the follow-up. Three patients, apparently deemed cured after an adequate PTH-drop on the day of surgery, showed persistence. Cure rate at primary surgery was 98.4%. Accuracy of our simplified protocol is 99.3%.

Pre-incision PTH is not superior to preoperative PTH blood test and can be omitted without compromising the sensitivity of cure prediction. One blood sample 15 min after resection, along with the postoperative PTH value on the day after surgery, is sufficient to predict the surgical outcome bearing the cost of a very low reoperation rate.