Prevention of intraoperative injuries of the laryngeal nerves. Literature review and own data

Based on the recent literature data, the analysis has been performed for the causes of the laryngeal nerve injuries and methods of their prevention during thyroid surgery. Literature data demonstrate that over the past 20 years the incidence of the laryngeal nerve injuries remained stable, from 0.1 to 3.0 % and more. It does not tend to decrease despite the introduction of neuromonitoring. The authors presented the peculiarities of monitoring the recurrent nerves and the external branch of the superior laryngeal nerve and options for evaluating its results. Based on own clinical material, the authors performed the comparative assessment of the number and nature of the laryngeal nerve injuries and resulted phonation disorders after surgical treatment of patients with goiter. The first group consisted of 208 patients who underwent only visual identification of recurrent nerves of the larynx during thyroid surgery. To prevent injuries of the external branch of the superior laryngeal nerve, the method of gradual and separate ligation of the superior thyroid artery and its branches on the thyroid capsule was used. The second group involved 201 patients who underwent surgery using intraoperative neuromonitoring of the recurrent and external branches of the superior laryngeal nerve by the author’s method. Analysis of the number of injuries from our own clinical material showed that in the group using intraoperative neuromonitoring they were almost 2.5 times less than in the group of patients who underwent surgeries with visual identification of nerves. It was established that the use of intraoperative neuromonitoring enabled an increase of the number of the identified laryngeal nerves and reduction in the rate of their trauma, laryngeal paresis and phonation disorders. It has been emphasized that intraoperative neuromonitoring does not replace the visual identification of laryngeal nerves, but complements it. In complex cases, its results are crucial for making a technical decision during the surgery. The amended topographic and anatomical proportions of the organs of the anterior part of the neck in different clinical forms of goiter create conditions for intraoperative injuries of the laryngeal nerves. The possibility of their occurrence and their number depend only on the correctness of the surgeon’s actions and their adequacy to the clinical situation. In order to prevent these injuries, the following important requirements for the surgeon and the technology of performing goiter surgery should be considered: knowledge of the anatomy of the anterior, lateral parts of the neck, larynx, superior anterior and posterior mediastinum; possession of elements of technology and sequence of surgery on the thyroid depending on the clinical situation, in particular cervical, thoracic, recurrent goiter, compression syndrome; dry operating field and calm, without haste of performance of operation at adequate lighting. In the complicated situations of tissue differentiation optics should be used as well as an intraoperative intermittent or continuous neuromonitoring.