Improved intraoperative verification of parathyroid glands by determining their autofluorescence in the infrared spectrum

Abstract

Background. Detection of parathyroid glands by spectroscopy of their autofluorescence in the near-infrared spectrum (NIRAF) is considered a promising intraoperative tool in addition to their verification with visual identification. The study was aimed to evaluate the role of NIRAF by using two different imaging systems to confirm parathyroid glands during operations for benign and malignant thyroid and parathyroid tumors. Materials and methods. The study included 62 patients who underwent verification of NIRAF by using two different imaging systems equipped with a near-infrared (NIR) camera during surgery. Intravenous fluorophore of indocyanine green was applied to amplify the NIRAF signal. Results. Normal parathyroid glands were identified and mobilized after a visual inspection in 50 patients (80 %), which was subsequently confirmed by evaluation with NIRAF spectroscopy. Determination of NIRAF in the parathyroid glands and their differentiation from lymph nodes was achieved in 8 (13 %) patients with papillary thyroid carcinoma. In 3 (5 %) patients, the parathyroid gland was identified in the area of the postoperative scar, using NIRAF but not by the visual identification. In 2 (3 %) cases, the appearance of the signal was determined but with a decrease in the intensity of the NIRAF from the parathyroid glands during their unintentional removal. The strong NIRAF signal intensity was observed from the parathyroid gland after changing the position of the NIR camera when using the Fluobeam 800 device at an angle of approximately 45–65° to the area of the parathyroid gland location. The Fluobeam LX demonstrated a satisfactory NIRAF signal without any specific changes in camera position. NIRAF signal was determined in the tissue of toxic thyroid adenomas. NIRAF signal of the low intensity was detected in the invasion of thyroid carcinoma in a capsule of a thyroid gland. No NIRAF signal was observed from metastatic and normal lymph nodes. Conclusions. The use of NIRAF parathyroid spectroscopy technology allows improving their imaging and verification as an additional method during surgery of the neck. The practical value of NIRAF spectroscopy of the parathyroid gland is increased in the case of reoperations due to the risk of accidental removal of the parathyroid gland as well as for differential diagnosis between the parathyroid gland and metastatic lymph nodes.

Keywords

• parathyroid autofluorescence, near-infrared fluorescence, hypoparathyroidism, parathyroid identification