Preface: Recurrent laryngeal nerve injury is a common complication of thyroid surgery, which can result in hoarseness, voice choking, voice reduction or voice loss. Clinically, we often encounter patients who undergo tracheotomy due to asphyxia after bilateral recurrent laryngeal nerve injury. The loss of voice in patients seriously affects their quality of life and causes conflict between doctors and patients. Even experienced thyroid surgeons, faced with the complex and variable laryngeal recurrent nerve, cannot guarantee paralaryngeal injury. Especially for non-dissecting injuries, the integrity of the recurrent laryngeal nerve cannot be determined by the naked eye. Who is doing thyroid surgery: At present, from township hospitals to top hospitals in Beijing and Shanghai, all of them are doing thyroid surgery, including general surgery, otolaryngology, head and neck surgery, and thyroid breast surgery. . In 2010, we successfully held a class on minimally invasive thyroid surgery and intraoperative laryngeal nerve monitoring in Shandong Province, which was attended by more than 100 participants. The best countermeasure for laryngeal nerve injury is prevention. At present, the main methods available are: 1, surgery under cervical plexus anesthesia, the patient remains awake during surgery, and the operator talks with the patient to understand the articulation situation. 2, intraoperative observation of vocal fold activity under the support of laryngeal mask airway (LMA) with the help of optical fiber endoscope, which has not been widely promoted due to the possibility of uncontrolled intraoperative airway. 3, intraoperative real-time monitoring of the laryngeal recurrent nerve through muscle The degree of laryngeal nerve injury can be determined by the electromyographic waveform, the prolongation of the latency period, and the reduction of the wave amplitude. Intraoperative neuromonitoring (INOM) refers to the application of various neurophysiological techniques to monitor the functional integrity of the nervous system at risk during surgery. It has been clinically used for nearly 20 years in developed countries and has been gradually improved, forming a complete intraoperative monitoring system across multiple disciplines. IONM has been used earlier in ENT, maxillofacial surgery, spine surgery, and neurology. IONM has revolutionized thyroid surgery in China, resulting in more rational surgery, improved safety, and fewer doctor-patient disputes. The indications for IONM are: thyroid swelling located on the dorsal side of the gland, suspected thyroid cancer or combined with thyroid inflammation; thyroid cancer with enlarged lymph nodes in the six regions of the nerve prone to injury; thyroid reoperation with disorganized levels and heavy adhesions; retrosternal thyroid; visceral transposition or subclavian artery variation, suspected non-returning laryngeal nerve; already unilateral laryngeal nerve paralysis, requiring contralateral surgery; laryngeal nerve Repair surgery after injury. Myoelectric receiving electrodes can be divided into four types: electrodes inserted into the vocal cord muscle with the help of laryngoscope, electrodes inserted into the vocal cord muscle through the cricoid ligament, surface electrodes acting on the posterior region of the cricoid cartilage, and surface electrodes of the tracheal tube. Technical principle: electrical stimulation directly contacts the recurrent laryngeal nerve, the recurrent laryngeal nerve transmits electrical stimulation, which innervates the vocal cord muscle to produce myoelectric signals, the recording electrodes receive electrical signals, and the monitor records the signals and emits beeping sounds. Animal models have shown that even with the application of 3mA current stimulation, there are no complications such as damage to nerves and muscles. History of nerve monitoring: In 1938, Lahey reported that intraoperative clear visualization of the recurrent laryngeal nerve had a significantly lower injury rate than that of unidentified individuals. In 1969, Fishberg and Lindholm were the first to use electromyography to monitor and identify the recurrent laryngeal nerve during surgery, which effectively reduced the injury rate of the recurrent laryngeal nerve. 1985, Jmaes et al. reported the use of electric current to stimulate the recurrent laryngeal nerve during surgery, and the surgeon could directly feel the contraction and movement of the cricothyroid In 1988, Lipton proposed the use of an electrode inserted into the vocal cords with the aid of a laryngoscope, and the operator held the nerve stimulation electrode to detect and record the activity of the laryngeal muscles through the recording device of the electromyograph. In 1996, Eisele reported a method of intraoperative EMG combined with tracheal intubation, in which surface EMG electrodes and a tracheal tube were placed on the medial side of the vocal cords for recording purposes. Monitoring method: After revealing the tracheoesophageal sulcus, the laryngeal recurrent nerve is searched for, and the laryngeal recurrent nerve is located along the route of the laryngeal recurrent nerve or the fiber strip of the suspected laryngeal recurrent nerve, and the suspected tissue is touched with the detector pen under the appropriate current. The laryngeal nerve is nearby and needs to be carefully isolated. The main objectives are to detect and identify the laryngeal nerve as early as possible, to determine its location, to clarify the damage caused by the surgery, to remove the cause, to avoid permanent nerve damage, to identify the ectopic fibers or nerve tissue, and to determine the site in the nerve repair, etc. It gives the patient and family a sense of psychological security, and the intraoperative electromyogram formed is evidence of successful surgery and greatly reduces medical disputes. The laryngeal recurrent nerve can have multiple branches, and the sensory branch can easily be taken as the nerve trunk if it is thick, thus causing motor branch injury. The application of neuromonitoring can prevent such events from occurring. The American Association for Endocrine Surgery has promoted the use of intraoperative laryngeal recurrent nerve monitors as a guideline. The use rate in the United States is 30%. In China, such operations have been carried out in Hong Kong, Beijing, Changchun, Guangzhou, Zhongshan, Sichuan, etc. Consensus of domestic and foreign scholars: Some scholars believe that the use of the recurrent laryngeal nerve monitor in initial or low-risk thyroid surgery does not reduce the rate of injury to the recurrent laryngeal nerve, but, on the contrary, increases the surgeon’s reliance on the instrument and reduces the surgical skill. IONM is not yet considered routine for thyroid surgery, but is very necessary in high-risk complex thyroid surgery. Intraoperative rather than postoperative determination of nerve function and timely repair of nerve damage can avoid the pain of secondary surgery while providing patients with a safer and more reliable surgical option. Although intraoperative nerve monitoring techniques are not yet perfect and can be interfered by anesthesia, electrical interference, machine malfunction, etc., and cannot yet achieve 100% accurate prediction of nerve function status, with false negative and false positive reports, we believe that the level of monitoring will be further improved with technological advances and improvements in methods.