Autofluorescence enhances intraoperative detection of parathyroid glands: a single-center comparative study

Permanent hypoparathyroidism after total thyroidectomy remains a major complication, occurring in close to 10% of cases and increasing risks of cardiac, renal, and metabolic morbidity. Near-infrared autofluorescence (NIRAF) imaging has emerged as a promising adjunct to improve parathyroid gland (PG) identification and preservation. This study evaluates the efficacy of NIRAF in enhancing intraoperative PG detection compared to conventional visual inspection.

This single-center retrospective cohort study included 349 patients undergoing total thyroidectomy. Outcomes were compared between a control group managed with visual PG identification alone (n = 126, 2014-2016) and a NIRAF-assisted group using Fluobeam LX^® imaging (n = 223, 2021-2023). The primary outcome was the mean number of PGs identified intraoperatively. Secondary outcomes included postoperative calcium and parathyroid hormone (PTH) levels, rates of PG autotransplantation, and inadvertent PG removal.

NIRAF use was associated with significantly improved intraoperative PG identification, with a higher mean number of glands visualized compared to controls (2.91 ± 0.98 vs. 2.59 ± 1.02; p = 0.004). Postoperative PTH levels were significantly higher in the NIRAF group (3.64 ± 1.72 vs. 3.03 ± 1.40 pmol/L; p < 0.001). Although postoperative calcium levels were lower in the NIRAF group (2.21 ± 0.11 vs. 2.29 ± 0.12 mmol/L; p < 0.001), the incidence of severe hypocalcemia (≤2.0 mmol/L) was low and comparable between groups (3.1% vs. 1.6%; p = 0.497). Rates of postoperative PTH <1.1 pmol/L, PG autotransplantation, and reimplantation did not differ significantly. Inadvertent PG removal was more frequent in the NIRAF group (20.6% vs. 5.6%; p < 0.001).

NIRAF imaging improves intraoperative identification of PG and is associated with higher early postoperative PTH levels. Although hypoparathyroidism did not differ between the two groups, the effect of NIRAF on permanent hypoparathyroidism requires prospective evaluation, particularly when combined with perfusion assessment using indocyanine green (ICG) angiography. Standardized use and surgeon training are necessary to optimize clinical outcomes.