Modern Approaches to Intraoperative Parathyroid Localization

Hyperparathyroidism is a prevalent endocrine disorder that frequently manifests with severe symptoms. Primary hyperparathyroidism is caused by parathyroid adenoma, whereas secondary and tertiary hyperparathyroidism are typically reported in patients with renal failure on maintenance hemodialysis. Modern cinacalcet-based therapy for secondary hyperparathyroidism has long-term positive effects. However, surgical resection of affected parathyroid glands remains the only curative therapy option in tertiary hyperparathyroidism. In polyglandular primary and (especially) tertiary hyperparathyroidism, parathyroidectomy requires the most accurate examination of the parathyroid glands, thyroid gland, and surrounding structures. Despite advancements in preoperative topical and functional diagnostic approaches, the specific location of the affected parathyroid glands remains unknown until surgery in half of patients. Existing parathyroid imaging techniques, such as intraoperative ultrasound, gamma detection, and methylene blue staining, have demonstrated limited efficacy. Fluorescence imaging using indocyanine green, aminolevulinic acid, and various autofluorescence modes is highly effective. However, its use is limited by high equipment costs, reproducibility issues, and difficulties in achieving the claimed results. This necessitates improvements of intraoperative parathyroid imaging algorithms, which is the focus of this review.