NON RECURRENT LARYNGEAL NERVE DISCOVERED WITH INTRA OPERATIVE NEUROMONITORING DURING MIVAT

The non recurrent laryngeal nerve (NRN) is an anatomical abnormality that, altrhought rare (0,03-1% on the right, only 4 cases on the left), represents a serious threat of recurrent lesioni during thyroidectomy. The existence of anatomical abnormalities such as the presence of the lusor artery can suggest a NRN, but are usually not assessed in the preoperative study. The use of intraoperative neuromonitoring (IONM) during total thyroidectomy may highlight the NRN during a setting phase of vagal potential registration. Therefore the lack of signal could suggest the presence of non recurrent laryngeal nerve. In this case, after separation of the carotid artery from the deep jugular vein, positioning the stimulus probe on the vagus nerve, there was no potential, and after checking the right position of the all electrodes, no signal has been recordered. The dissection of the neurovascular bundle of the neck continues cranially, until the existence of a nerve that runs parallel to the vagus is shows. The stimulation of this nerve produced the recording of the signal and demonstrates the existence of a lower laryngeal nerve that comes out from the vagus at the level of the pharynx. Continuing the dissection of the neurovascular bundle upwards, the emergence of the inferior laryngeal nerve is found. The stimulation of the vagus nerve above the point of emergency allows the recording of the signal. The electrode of continuos monitoring is placed on vagus nerve above the emergence of the NRN. At the level of the thyroid gland the inferior laryngeal nerve is found, as it runs below the carotid artery to the pharynx, and it is confirmed by the registration of the potential.