This single-center, prospective, three-phase observational cohort quantifies the relationship between indocyanine green (ICG) fluorescence and early parathyroid function. Adult patients scheduled for unilateral thyroid lobectomy with autotransplantation of the ipsilateral inferior parathyroid gland are enrolled. After intravenous ICG 25 µg/kg, peak fluorescence of the superior parathyroid gland and the common carotid artery (CCA) is recorded at 60-120 seconds to calculate the ratio R = PTG/CCA. Serum parathyroid hormone (PTH) is measured 30 minutes post-operatively. A derivation cohort (\~120 patients) generates R-based thresholds for in-situ preservation versus autotransplantation, which are prospectively validated in an independent cohort (60 patients) together with decision-curve analysis of clinical net benefit.
Scheduled for unilateral thyroid lobectomy plus central (VI-level) lymph-node dissection.
Complete identification and in-situ preservation of the ipsilateral superior parathyroid gland;
Complete identification and autotransplantation of the ipsilateral inferior parathyroid gland.
Serum 25-hydroxy-vitamin D ≥ 30 ng/mL at baseline; patients below this level may be enrolled after standardized vitamin-D and calcium supplementation with re-test confirming ≥ 30 ng/mL.
Prior surgery on the thyroid or parathyroid glands.
Severe hepatic or renal impairment, or other serious metabolic bone disease.
Pregnancy or lactation.
Known hypersensitivity to indocyanine green or iodine-containing compounds.