Keywords
Parathyroidectomy, Primary Hyperparathyroidism, Intra-Operative Parathyroid Hormone Monitoring, Parathyroid Adenoma, Operative Time
KEY POINTS
INTRODUCTION
Primary Hyperparathyroidism (PHPT), a benign hormonal disorder characterized by a high serum calcium concentration and an inappropriately increased parathyroid hormone, is a relatively common medical condition, with prevalence of 233 to 100,000 in women, and 85 to 100,000 in men.(1) Approximately 88% of cases are due to single adenoma.(2)
The treatment of choice for PHPT is parathyroidectomy with a cure rate of up to 99%.(3–7)
Over the last few decades, the minimally invasive parathyroidectomy has gradually replaced the standard procedure – bilateral neck exploration(8) – due to preoperative localization techniques and intraoperative parathyroid hormone monitoring (IOPTH).
Although preoperative localization techniques vary, Ultrasonography (US) and technetium Sestamibi scintigraphy (Sestamibi) reach a high sensitivity rate of up to 90%.(6,9–11) Other imaging modalities, such as Computed Tomography (CT) and MRI, are acceptable as well.
The definitive treatment for PHPT due to single adenoma, is resection of the affected gland. Cure is defined as a decline in calcium levels to normal (8.4-10.5 mg/dL), six months post-surgery.
Pre-operative imaging for adenoma localization varies between centers worldwide.
The routine use of IOPTH is a long-debated topic in the literature. In a recent survey in the United States, 74% of surgeons responded they always use IOPTH, regardless of the clinical setting.(12)
The American Association of Endocrine Surgeons recommends performing IOPTH in all parathyroidectomies.(13) Several studies have shown that the use of IOPTH results in cure rates of 97-99%.(3–5) Furthermore, studies have also shown that when IOPTH is not performed, there is a decline in operative success.(5,13,14)
Notwithstanding the above, the European Society of Endocrine Surgeons (ESES) recommends that when pre-operative localization with Sestamibi and US is concordant for single gland disease, the use of IOPTH is of little added value (evidence at levels Ib-III, recommendation grades A/B).(15) Other studies have shown that when two imaging modalities are concordant pre-operatively, there is no difference in cure rates when IOPTH is not used.(6,16,17) In addition, some studies have shown that unrelated to imaging modalities, IOPTH usage does not change the surgical success rates.(18–20) Furthermore, in a study that examined 15,000 parathyroidectomies, the authors argue that even 90% decline in IOPTH monitoring during surgery, cannot assure cure. They suggest that all parathyroidectomies should be done with bilateral exploration, without IOPTH monitoring.(21)
Regarding operating room time and operating room economics, a comprehensive cost analysis published in 2010 showed that many parameters should be taken into consideration when assessing the cost-benefit of using IOPTH, the most important of which is the rate of multi-glandular disease.(22)
A decade ago, a study published by our group demonstrated no added value for IOPTH when US and MIBI are concordant.(6) Since then, we have changed our practice and utilized IOPTH only in selected cases (pre-operative imaging is not concordant; suspected multiglandular disease; secondary or tertiary hyperparathyroidism; patients with a diagnosis of MEN1 or MEN2A; revision surgery).
The main goal of the present study was to revisit our protocol following 10 years of experience, by investigating the cure rates of primary hyperparathyroidism since the protocol had changed, compared to the period when IOPTH was used routinely. The secondary goal was to investigate if operating room time can be saved when IOPTH is not used.
MATERIALS AND METHODS