Fluorescent technologies for intraoperative parathyroid identification

Abstract

Parathyroid fluorescence has emerged as a useful adjunct for the detection and preservation of parathyroid glands during both thyroidectomy and parathyroidectomy. When viewed under near-infrared light, parathyroid tissue has autofluorescent properties, which can be used to identify the parathyroid glands and distinguish them from the surrounding cervical tissues, including lymph nodes, thyroid, and fat. This near-infrared autofluorescence (NIRAF) is based on intrinsic fluorophores within parathyroid tissue and does not evaluate tissue viability. However, the addition of an intravascular fluorescent contrast, such as indocyanine green, can help evaluate gland perfusion. These techniques are safe, require no radiation, and can be easily integrated into the surgical workflow. Though long-term clinical outcomes data, including improvement of post-thyroidectomy hypoparathyroidism and cure of hyperparathyroidism using parathyroid NIRAF and contrast-enhanced parathyroid fluorescence is currently lacking, promising data is emerging that these techniques may improve parathyroid identification and preservation during cervical surgery. They may also be particularly useful in teaching trainees. In this article, we describe the techniques of probe-based and image-based detection of parathyroid NIRAF, as well as contrast-enhanced parathyroid fluorescence. We explore the current literature surrounding these modalities, discuss advantages and limitations of the various techniques, and provide practical guidance for their use and integration into surgical practice.