USING INDOCYANIN GREEN IN ENDOSCOPIC THYROID SURGERY. OUR FIRST EXPERIENCE
Authors: Beloshitskiy M. E. , Britvin T.A. , Semenov D. Yu. 
Published: January 2021

One of the directions of the safety strategy in thyroid surgery is to preserve the integrity of the recurrent laryngeal nerves (RLN). In this regard, we used «Indocyanin green – Pulsion» (ICG, Germany) to improve the quality of visual control of the RLN during endoscopic operations on the thyroid gland. Goal: to evaluate the possibility of RLN visualization during endoscopic operations on the thyroid gland using fluorescent navigation with the ICG. Materials and methods. The results of 52 endoscopic hemithyroidectomies from axillary approach for various
thyroid diseases were analyzed. Surgical interventions were performed using the KARL STORZ endovideosurgical stand, with the ability to work in double mode: with white light visualization and ICG-fluorescent visualization. In 14 cases, intraoperative RLN monitoring was performed using the ISIS C2 neuromonitor («Inomed», Germany), in 18 cases RLN imaging was performed in standard white light, and in another 20 cases – in ICG-fluorescence mode. Results. Endoscopic hemithyroidectomy from axillary access was performed according to the standard method in white light mode until the anatomical structure was detected based on the topographic location, diameter and color of the corresponding RLN. Then the patient received intravenous administration of the drug with a volume of 5.0 ml. The camera switched to the NIR range, effective fluorescence in the operating field area appeared after 10-15 seconds and lasted up to 15 minutes. In 9 patients, the anatomical structure detected in the standard mode did not change its whitish color when the camera was repeatedly switched to NIR mode and was regarded as RLN. In 6 patients, the anatomical structure resembling RLN, when switching the camera to NIR mode, turned bright blue or green depending on the selected spectrum, which corresponds to the blood vessel, and therefore the search for the RLN continued. In 5 patients, in the projection of the possible location of the RLN in the white light mode, several anatomical structures were simultaneously detected that run parallel to each other along the side wall of the trachea, similar in color, diameter and structure. In these observations, only the introduction of ICG to change the color when switching camera modes allowed to distinguish blood vessels from the RLN.
In the postoperative period, in the group of patients who used the ICG-fluorescent RLN imaging technique, there were no violations of the mobility of the vocal folds according to the results of laryngeal endosonography. Of the 14 patients whose RLN control was performed using variable neuromonitoring, 1 observation showed transient laryngeal paresis. In the group of patients whose RLN was visualized only in the standard white light mode, persistent paresis of the vocal fold was diagnosed in 1, and transient paresis was diagnosed in 1 more patient.
Conclusion: Fluorescent imaging using ICG allows differentiating vascular and neural structures, thereby evaluating the course of the RLN, and may have certain clinical prospects for thyroid endoscopic surgery.