Читать книгу Advances in Neurolaryngology - Группа авторов - Страница 52

Intraoperative neural monitoring (IONM) of recurrent laryngeal nerve function and of the external branch of the superior laryngeal nerve is nowadays a standard tool during thyroid surgery. IONM is mostly performed using endotracheal tube surface electrodes for LEMG analysis [12]. It has now also been shown that right vagus, left vagus, and recurrent laryngeal nerve latencies are characteristic of the individual nerves and allow identification of an intact left or right vagus/ recurrent laryngeal nerve system. Timed recording of vagal waveform during IONM can therefore document intact ipsilateral vagal-recurrent laryngeal nerve neural circuit at the end of thyroid surgery [13]. As multichannel IONM becomes more and more available, it will allow for the simultaneous evaluation of the function of other laryngeal muscles such as the CT and also the cricopharyngeus muscle (CP). We know now that both the recurrent laryngeal nerve and the external branch of the superior laryngeal nerve contribute to the motor innervation of the CP muscle [14]. The laryngeal nerve supply is even more complex and variable than established in classic anatomical descriptions. By stimulation of the pharyngeal plexus during thyroid surgery, Uludag et al. [15] have shown recently that the plexus pharyngeus can also contribute to ipsilateral vocal cord innervation by reflex or direct innervation patterns.

Not only is LEMG of the TA of interest after thyroid surgery in the case of patients with suspected recurrent laryngeal nerve lesion but also the LEMG of the CT is now a well-established method to detect an injury of the external branch of the superior laryngeal nerve. Spontaneous activity in the CT and an MUP analysis can be performed as effectively as from the TA [16].