Fluorescence-guided detection of normal parathyroid glands using 5-ALA during thyroid surgery

Abstract

It is important to identify and save normal parathyroid glands during thyroid surgery to maintain blood calcium level. But detection of normal parathyroid glands is often difficult in the thyroid surgery. Fluorescence-guided parathyroidectomy for human hyperparathyroidism has already been proved. However, there are few reports of fluorescence-guided normal human parathyroid detection. Nine patients with thyroid benign tumor were given 20 mg/kg body weight of 5-Aminolevulinic Acid (5-ALA) orally 5 hours before exposure of the parathyroid glands. After the posterior surface of the thyroid was exposed and the recurrent laryngeal nerve was identified, we illuminated the area using 405nm bluish purple light. The bluish purple light enabled identification of the normal parathyroid glands by their red fluorescence. On the other hand, surrounding structures such as thyroid, muscle, and soft tissue remained nonfluorescent. The tissue was subsequently shown by histopathological analysis to be normal parathyroid gland. 5-ALA can support detection of normal parathyroid in human neck surgery.