Vocal fold palsy, also known as laryngeal nerve palsy, is caused by loss of innervation of the vocal folds secondary to injury to the vagus nerve, superior laryngeal nerve, or the recurrent laryngeal nerve, and is mainly characterized by dysfunction of articulation, swallowing, or breathing. Vocal cord palsy is a clinical manifestation rather than a separate disease. When the motor nerve of the larynx is damaged, three types of vocal fold palsy can occur: abduction, adduction, or relaxation of muscle tone. Clinically, left-sided vocal fold palsy is more common because of the longer stroke of the left recurrent laryngeal nerve. The etiology of vocal fold palsy is complex and varied, and can be divided into central and peripheral according to the location of nerve damage, with peripheral being the most common. 1, central: both sides of the cerebral cortex of the laryngeal motor center has a nerve bundle and the nucleus of suspicion connected to the two sides, so each side of the muscle to receive impulses from both sides of the cerebral cortex, so cortical lesions caused by laryngeal paralysis, clinically very rare. Cerebral hemorrhage, basilar aneurysm, inflammation of the posterior cranial fossa, and tumors of the medulla oblongata and pontine brain can all cause vocal cord paralysis. 2.Peripheral: Any laryngeal paralysis caused by a lesion that occurs mainly in any part of the laryngeal nerve or vagus nerve before it leaves the jugular foramen and divides into the laryngeal nerve is considered peripheral. Fractures of the skull base, thyroid tumors, various traumas of the neck and larynx, malignant tumors of the larynx, benign and malignant tumors of the neck or skull base, compression or invasion of mediastinal tumors or esophageal tumors, compression or invasion of mediastinal metastatic lymph nodes, tuberculous adhesions of the lung apices, pericarditis, and peripheral neuritis can cause vocal cord paralysis. It should be emphasized that thyroid surgery, carotid endarterectomy, anterior cervical approach cervical spine surgery, skull base surgery, thoracic surgery, and tracheal intubation are the main causes of medically induced injury to the superior laryngeal nerve, the recurrent laryngeal nerve, or the vagus nerve. Vocal cord palsy caused by medically induced injury should be treated actively to avoid delaying the best time for treatment. Clinical manifestations According to the location and degree of nerve damage, it can be divided into supraglottic nerve, recurrent laryngeal nerve palsy or mixed nerve palsy, unilateral palsy or bilateral palsy, and complete palsy or incomplete palsy, etc. 1, unilateral incomplete palsy: mainly for the vocal fold abduction disorder, the symptoms are not significant. Laryngoscopy shows that one side of the vocal folds is near the midline and cannot be abducted during inspiration, while the vocal folds can be closed during pronunciation. 2.Unilateral complete palsy: the abduction and induction of the vocal folds on the affected side are gone. Laryngoscopic examination shows that the vocal folds on one side are fixed in the paramedian position, the arytenoid cartilage is tilted forward, the vocal folds on the affected side are lower than those on the healthy side, the vocal folds cannot be closed during articulation, and the articulation is hoarse and weak. 3. Bilateral incomplete palsy: rare, mostly due to thyroid surgery or laryngeal trauma. Both vocal folds cannot be abducted and are close to each other in the midline, and the vocal folds are fissured. The patient can be asymptomatic when calm, but often feels difficulty in breathing during physical activity. Once there is an upper respiratory tract infection, severe respiratory distress can occur. 4. Bilateral complete palsy: both vocal folds are in paracentral position, neither closed nor abducted, pronunciation is hoarse and weak, general breathing is normal, but food and saliva are easily inhaled into the lower respiratory tract by mistake, causing choking and coughing. 5.Bilateral vocal fold inversion palsy: mostly seen in functional loss of voice, the vocal folds cannot be inward when pronouncing, but coughing has sound. Treatment Vocal fold palsy should be treated according to its cause. The current treatment for vocal fold palsy is divided into three stages: etiological treatment, articulation training and surgical treatment. In terms of treatment, according to the type of vocal cord palsy, there are two types of treatment: bilateral and unilateral vocal cord palsy: the main goal of unilateral vocal cord palsy treatment is to improve articulation and reduce misaspiration, including vocal cord internal transposition and laryngeal nerve decompression or reconstruction; patients with bilateral vocal cord palsy often have severe dyspnea and laryngeal tinnitus, and the main goal of treatment is to reduce airway obstruction and preserve articulatory function as much as possible. In patients with unilateral laryngeal nerve injury resulting in vocal fold paralysis, patients with injury not exceeding 3 months can be treated by laryngeal nerve decompression or laryngeal nerve repair; in patients with more than 3 months, the vocal folds can be internally displaced by thyroid cartilage molding and fat injection into the paramedian hiatus, and the hoarseness of the patient’s voice is found to be significantly improved by regular follow-up. For patients with bilateral vocal fold paralysis, after treatment with microscopic CO2 laser-assisted arytenoid cartilage resection or external laryngeal approach arytenoid cartilage resection for vocal fold external migration, the patients’ dyspnea was significantly relieved and the quality of articulation was well preserved. In patients with bilateral vocal cord paralysis who had undergone tracheotomy for dyspnea, CO2 laser microscopic arytenoid chondroidectomy relieved dyspnea, and the patients were extubated successfully after the operation with good preservation of articulation.