Title : Experience with intraoperative neuromonitoring of the laryngeal nerves during endovideoscopic surgery on the thyroid.
Abstract:
Among the specific complications of operations on the organs of the neck, the main place is occupied by a violation of the mobility of the vocal cords. Thanks to the introduction of non-invasive methods for recording a signal from the vocal folds, using intraoperative neuromonitoring (IONM), it became possible to evaluate the preservation of laryngeal nerve, to predict the function of the larynx in the postoperative period, and thereby prevent bilateral paresis.
Methods: Modern devices for IONM allow not only variable monitoring, but also constant monitoring, which allows you to monitor the safety of recurrent laryngeal nerves during the operation every second. Issues of using IONM for endoscopic thyroid surgery are practically not covered in the literature, and these surgical interventions have their own characteristics that need to be studied.
We try to adhere to a certain algorithm of actions:
1.Mandatory is the evaluation of the function of the vocal cords in the pre-operative stage.
2. Initial action is the identification and testing of the vagus nerve
3 The vagus nerve should be tested at the end of the operation
4. Determination of the absence of disturbances of function of vocal cords in the postoperative period.
For the localization of the nerve, a monopolar stimulating electrode is more convenient.
The bipolar electrode has a narrower current distribution parameter, but can also be used for nerve search.
There are a number of problems that can distort the true picture: 1) presence in the nerve area of blood or other fluid; 2) insufficient close attachment of active electrode to the nerve; 3) high temperature in the intervention area 4) migration of passive electrodes or the intubation tube itself.
Results: In the period from May 2013 to April 2020, 812 patients with various diseases of the thyroid and parathyroid glands underwent endoscopic interventions. In all cases, axillary mammary access was used.Characteristics of patients by gender: 683 women and 129 men, the average age was 35 years.We performed the following surgical interventions: thyroidectomy - in 292 cases, hemithyroidectomy – 463, subtotal resection - 57, the volume of the thyroid gland ranged from 17 ml to 350. The access was unidirectional. We consider the visualization of recurrent nerve and parathyroid gland to be a standard step.We dealt with postoperative paresis in 29 cases (4.7%), as a rule it lasted up to 3 months Two methods were used to determine the position of TFT and electrodes on the vocal cords at the beginning of the operation: stimulation through the larynx and testing the vagus nerve on one side.
Conclusion: The constant use of IONM provides a more comfortable and safe operation, makes it possible to identify the laryngeal nerves and significantly reduces the risk of damage, improves the quality of intraoperative navigation, especially when using constant neuromonitoring. Assessment of the amplitude and latency of the electromyographic signal allows predicting the function of the larynx in the postoperative period.
