Indocyanine Green Angiography for Parathyroid Gland Evaluation during Transoral Endoscopic Thyroidectomy

Indocyanine green (ICG) angiography, a real-time intraoperative imaging technique, is associated with better parathyroid identification and functional evaluation during open thyroidectomy. However, the benefits of ICG fluorescence imaging application in transoral endoscopic thyroidectomy are not well-documented. Consecutive patients who underwent transoral endoscopic thyroidectomy were retrospectively reviewed. Parathyroid glands were assessed with visual inspection followed by ICG angiography. The fluorescence intensity of all parathyroid glands was recorded. In total, 158 parathyroid glands from 60 patients (41 underwent lobectomy and 19 underwent total thyroidectomy) were eligible for evaluation. A total of 135 parathyroid glands (85.4%) were identified, including nine glands (5.7%) that were solely localized because of ICG angiography. Incidental parathyroidectomy occurred in 12 patients with predominant inferior gland (83.3%) and associated with central neck dissection (66.7%). Among patients receiving total thyroidectomy, patients who retained at least one well-perfused parathyroid gland had higher parathyroid hormone (PTH) level and were less likely to develop hypoparathyroidism on postoperative day one than those without any well-perfused ICG-enhanced parathyroid gland (p = 0.038). In addition, the duration of calcium supplementation to maintain normocalcemia was also shorter. ICG angiography is a feasible adjunct procedure for parathyroid identification and postoperative functional prediction in transoral endoscopic thyroidectomy.