Identification and monitoring of laryngeal nerves: technologies and problems. Review

The review paper is devoted to an important problem of surgical treatment of thyroid diseases: avoiding injuries to the nerves of the larynx and the consequences associated with them. One of the ways to solve it is the identification and monitoring of nerves during surgery. An analysis of existing methods and technologies used for identification and monitoring of laryngeal nerves has been carried out. The issues of effectiveness and expediency of their application were considered. The definition of the terms «nerve identification» and «neuromonitoring of laryngeal nerves» has been outlined. The term «nerve identification» defines the procedure for identifying a nerve among the tissues of a surgical wound. Neuromonitoring is the constant monitoring of the nerve during the operation. In the prevention of laryngeal nerve injuries, it is important to combine these two actions and follow their sequence, the nerve identification should be the first, following by its monitoring during the surgery. The authors singled out two stages in the processes of identification and neuromonitoring of laryngeal nerves, electrical stimulation and recording the results of electrical stimulation. A detailed description of each of the stages is given, as well as methods and means of their implementation, technologies, positive and negative aspects. The author’s method of identification and neuromonitoring of laryngeal nerves using a laryngeal mask is described, which is based on the neurochronaxic theory of sound formation. The authors conclude the advisability of the identification and neuromonitoring of laryngeal nerves during operations on the thyroid gland, as they allow reducing the number of paresis of the larynx. Modern IONM technologies do not provide absolute accuracy. Some of them are technically complex, and the obtained results depend on many factors that significantly affect the reliability. The need to create a reliable, physiologically based, easy‑to‑use technology for identification and neuromonitoring of laryngeal nerves is emphasized.