A Comprehensive Review of Intraoperative Parathyroid Hormone Monitoring A Comprehensive Review of Intraoperative Parathyroid Hormone Monitoring

Intraoperative parathyroid hormone monitoring (IOPTH) has changed the surgical approach to primary hyperparathyroidism (PHPT). The traditional approach for the treatment of PHPT is a bilateral neck exploration (BNE), which entails the identification of all parathyroid glands and resection of the abnormal glands. However, with the advent of improved surgical adjuncts, including preoperative ultrasound and sestamibi scintigraphy, and IOPTH monitoring, the pendulum has swung from bilateral exploration to minimally invasive parathyroidectomy. Minimally invasive parathyroidectomy (MIP) encompasses a myriad of “minimally invasive” procedures and includes focused, unilateral, videoscopic, endoscopic, and robotic parathyroidectomies. The standard that MIP is measured against is the traditional bilateral neck exploration which results in a >95% success rate in experienced hands.1-4 The most common and widely accepted adjuncts used with MIP are ultrasound (US) scanning, sestamibi (MIBI) scanning, and IOPTH. The reported accuracy for identifying a single adenoma is 71 to 80% for US and 74 to 88% for MIBI, and 64 to 95% when both are combined.5-8 On the other hand, the accuracy for identifying multigland disease is lower with either single (69% for US and 49% for MIBI) or combined (62%) imaging modalities.6 IOPTH is reported to have an overall accuracy of 80%.5 Similar to preoperative localizing studies, the best results of IOPTH occur in patients with single gland disease (87 to 99%),5,8 but IOPTH assay is less accurate in patients with multigland disease (58%).5 Others, contend that IOPTH is accurate and allows for the successful operative treatment of patients with both single gland and multiple gland parathyroid disease, and rely on parathyroid gland function rather than morphology or histology.9 Not many issues in surgery have been debated as extensively as the use of IOPTH during parathyroid surgery. Proponents supporting IOPTH (in conjunction with localizing studies) propose that the use of IOPTH allows for a less invasive approach, while providing the same operative success and risk of recurrence as a BNE.10,11 On the other hand, opponents of IOPTH argue that a minimally invasive approach underestimates the rate of multigland disease and can potentially lead to operative failure.6 A minimally invasive approach also allows for a shorter hospital stay, although most patients having a bilateral approach can be discharged within 24 hours, a more cosmetic appealing incision, and less postoperative pain are also reported. The risk of surgical complications can be argued to occur less frequently with MIP since only one side of the neck or two parathyroid glands and one recurrent laryngeal nerve are at risk. However, this argument is hard to defend because the complication risk during BNE is already nominal (1%) in the hands of experienced parathyroid surgeons. The contention surrounding the use of IOPTH is centered on the potential risk of operative failure. This comprehensive overview outlines the use of IOPTH during parathyroid surgery and outlines the arguments for and against the use of routine IOPTH.