Unexpected mapping of recurrent laryngeal nerve by fluorescence-guided surgery using near-infrared indocyanine green angiography

Abstract

Background. The recurrent laryngeal nerve (RLN) damage and parathyroid gland injury are the most severe complications of thyroid surgery. The possibility of RLN confirmation in the near-infrared spectrum after the injection of indocyanine green (ICG) was not yet been studied. Aim: to evaluate the ICG angiography for the identification of RLN during thyroid and parathyroid surgery. Materials and methods. ICG angiography of RLN was performed in 7 patients. An intraoperative neuromonitoring was applied as a method of controlling RLN. During the operation, parathyroid glands and RLN were identified by visual inspection (naked eye). To further confirm the location of the parathyroid glands by autofluorescence, an intravenous injection of ICG was performed with a concentration of 0.25 mg/kg followed by the application of the image-based system. Results. A good signal was achieved in the near-infrared spectrum from the RLN in all cases after the ICG injection. Sufficient blood perfusion of the RLN could be considered as a reasonable explanation for the exhibition of a good ICG near-infrared signal. Conclusions. ICG use might be a helpful approach for the confirmation of the RLN in addition to routine visual identification. Such function could be applied during fluorescence-guided surgery to evaluate the parathyroid gland autofluorescence. Visualization of RLN by ICG angiography is considered as an additional useful feature to prevent RLN injury.