Is minimally invasive parathyroidectomy without QPTH monitoring justified?

It is matter of discussion if quick parathyroid hormone (QPTH) monitoring is helpful in patients with primary hyperparathyroidism (PHPT) and "localized single-gland disease" (SGD; concordant sestamibi and ultrasound results) to further increase the rate of success (permanent normocalcemia) of performing selective parathyroidectomy by minimally invasive parathyroid exploration (MIP). The aim of this study was to evaluate if a randomized controlled trial was justified in order to clarify this discussion.

The prospective database of patients with sporadic PHPT, SGD, MIP, and QPTH monitoring (1999-2005) was evaluated regarding the "conversion rate" to bilateral exploration and permanent normocalcemia ("QPTH" group). Retrospectively, the patients were analyzed a second time "without" applying QPTH monitoring ("non-QPTH" group). Statistical differences between both groups were calculated (McNemar's test).

By definition, 338 patients with "localized SGD" underwent MIP. MIP was finished in 308 (91.1%) patients. Five of 308 patients (1.6%) showed persisting (n = 1) or recurrent disease (n = 4). In 30 of 338 patients (8.9%), a conversion to bilateral exploration was necessary (false preoperative localization 15 patients--one patient not cured; multiple-gland disease correctly indicated by QPTH monitoring 15 patients--one patient not cured). Analyzing the "non-QPTH" group, 14 additional patients showed persisting disease. Thus, without using QPTH monitoring, the rate of persisting PHPT would increase from 0.9% (three patients) to 5.0% (17 patients; p = 0.0005).

Intraoperative QPTH assay seems necessary even in patients with "localized SGD" by two techniques in an endemic goiter region. Abandoning QPTH monitoring would more than double the rate of persisting disease. A randomized trial seems not to be justified.