The recurrent nerve of the larynx, in Latin ─ n. laryngeus recurrens is one of the branches of the cervical part of the vagus nerve, where in its main trunk the discharge from the right side is observed at the level of the artery located subclavian (a. subclavia). From the left edge ─ at the level of the aortic arch. When bending around these vessels from the front to the back, the recurrent laryngeal nerve is directed upward towards the groove located between the trachea with the esophagus, while the terminal branches reach the laryngeal region. Throughout its length, the laryngeal nerve is divided by the following branches:

• branches of the trachea, heading to the anterior tracheal surface, located below. On their way, they are part of the connections with sympathetic branches, go to the trachea;
• the branches of the esophagus that innervate it;
• lower laryngeal nerve. The recurrent laryngeal nerve is the terminal branch of this nerve. On its way, this inferior nerve is divided into a branch located in front and behind:
• the thyroid, cricoid, thyroid laryngeal, vocal, scary laryngeal muscles are innervated by the anterior branch;
• the back consists of both sensitive, suitable for the laryngeal mucosa below the glottis, and motor fibers. The latter are innervated by the transverse with arytenoid, cricoid muscles.

How does laryngeal dysfunction manifest?

When the vagus nerve is damaged, its branches with nuclei, this leads to paresis of the laryngeal recurrent nerve. This paresis is observed more often, due to a pathological process that occurs in the larynx region, lesions of the NA, chest cavity pathology. And if intercostal neuralgia can be treated at home, then with the laryngeal nerve, everything is somewhat more complicated.

Cause

Paresis of the laryngeal zone is often caused by a pathological process with paresis of the left recurrent nerve and right. Large extent n. laryngeus recurrens, its entry into the laryngeal zone from the cavity to the chest, contact with numerous structural components in anatomy leads to the risk of destruction of nerve tissues in its different zones. The left side of the recurrent nerve endings performs aortic bending of the arch, the aneurysm contributes to their compression. And their right part goes near the upper lobe of the right lung located, can be transmitted by the adhesions of the pleura in this area. Paresis and other damage to this nerve in the larynx occurs due to the following reasons:

• injury to the laryngeal region;
• pleural inflammation, neoplasms in the pleura;
• inflammation of the pericardium;
• oncological pathology;
• inflammation of the lymph nodes;
• cystic neoplasms in the mediastinal region;
• pathology of the thyroid gland, esophagus.

Laryngeal paresis is also possible with toxic damage, n. laryngeus recurrens becomes inflamed, damage to this nerve is toxic in nature with various intoxications.

It is also able to develop due to diabetes mellitus, infectious pathology. Neuropathic laryngeal paresis occurs as a result of surgical intervention on the thyroid gland with its complete or partial removal. Paresis of the laryngeal zone can also cause:

• syndrome affecting the cranial nerves;
• syphilis, poliomyelitis lesion of the NS;
• clostridial bacteria;
• the formation of cavities in the spinal cord;
• vascular atherosclerosis of the brain;
• strokes;
• traumatic brain injury.

Paresis of the laryngeal nerve usually occurs on both sides due to the fact that the neuropathic pathways intersect before entering the brain stem zone.

Symptoms

Injury to the recurrent nerve results in a variety of symptoms. The vocal cords become less mobile, and laryngeal paresis also disrupts the formation of the voice, the function of respiration. Laryngeal paresis sequentially involves the internal muscle fibers of the larynx in a destructive state: first, the cricoid muscle becomes dysfunctional, expanding the glottis and abducting vocal folds, then become weak and the adductor myofibers, narrowing the larynx (larynx), reducing the ligamentous laryngeal apparatus, become weak and paralyzed. The vocal cord (ligamenta vocalia) on the affected area is located in the middle, then, when the adductors are weakened, its location becomes intermediate. At first, laryngeal paresis does not disturb voice formation due to the adjacent unaffected vocal fold to the ligament, which is located in the middle of the affected area. Respiratory function has not yet been impaired, it becomes difficult with physical overload. Then the laryngeal paresis passes into the stage at which the glottis does not completely close when the voice is formed, the person's voice becomes hoarse. Months later, in a patient with laryngeal paresis, the course of the disease is compensatory with the formed hyperadductive vocal fold in the normal zone, with its tight fit to the ligament in which the paresis. As a result, the normal voice is restored, but the person cannot sing. When paresis occurs on both sides, then at the first stage breathing is dysfunctional, asphyxia may develop. This is due to the middle position of both vocal cords, when the air is closed, it encounters an obstacle in its path. The clinical picture is expressed by an infrequent breathing process, noise and retraction of the pits located above the clavicle, the epigastric region and zones located between the ribs during inspiration, and they protrude with exhalation. The position of the patient's body is forced, often sitting with his hands resting on the edge of the furniture, he is very scared, the skin is bluish in color. Minimal physical activity leads to a deterioration in well-being. A few days later, the ligamenta vocalia is intermediate with a gap formation and normalization of respiration. However, during physical work, hypoxia appears.

Diagnosis

The purpose of diagnostic measures for neuropathic laryngeal paresis is both in the diagnosis and the reasons for its occurrence. The patient needs the following consultations:

• otolaryngological;
• neurological;
• neurosurgical;
• endocrinological;
• surgical.

A patient with this pathology must be thoroughly examined. This is possible thanks to the following research activities:

• computed tomography;
• x-ray, microlaryngoscopic examination of the laryngeal zone;
• diagnostics of voice functions with stroboscopic, electroglographic, phonetographic studies, as well as determining the time of maximum voice formation;
• electromyographic examination of muscle fibers of the larynx.

To exclude the cause of laryngeal pathology in diseases in the chest, chest x-ray, computed tomography of the mediastinal region, ultrasound cardiac diagnostics, esophageal radiography are performed. You also need to do an ultrasound examination of the thyroid gland. With TBI, magnetic resonance imaging of the brain is required. Laryngeal paresis is differentiated from myopathological and functional, it should also be distinguished from inflammation or trauma of the scapular joint, pseudo-croup, diphtheria croup, bronchoastmatic attacks, congenital sridor.

How to treat?

If the patient has laryngeal paresis or paralysis, then therapeutic measures are aimed at eliminating the underlying pathology with the cause that caused this problem. For example, if paresis is due to vocal fatigue, then you need to take a vacation in such work. In case of an inflammatory process, the doctor will prescribe non-steroidal anti-inflammatory drugs. When the nerve fiber is injured, the use of thermal procedures is recommended. An intoxication with an infectious nature of the disease is treated, respectively, with detoxification therapy with the treatment of infectious pathology. To eliminate the psychogenic cause of the disease, the appointment of sedatives, psychotherapeutic consultation are recommended.

A good result is given by physiotherapy procedures using electrophoresis, acupuncture, voice with breathing exercises.

In some situations, for example, when laryngeal paralysis occurs on both sides, a surgical tracheotomy operation is shown, in which the skin, the laryngeal area is cut, a special tube is inserted, the incision site is sutured, the tube is fixed to the cervical region. With unilateral laryngeal paralysis, the laryngeal region is reinnervated, using a thyroplastic or implant surgical method. Breathing exercises include:

• blowing out and inhaling at a slow pace;
• blowing out using a harmonica;
• puff out cheeks, air is slowly released through the gap;
• gymnastics for the formation of a long breath and many others.

Gymnastic exercises for the cervical muscles, vocal gymnastics with the supervision of an appropriate specialist, which consists in correcting verbal, syllable sound pronunciations, will also be useful.

Weakness of the internal muscles of the larynx associated with a violation of their innervation. Unilateral neuropathic paresis of the larynx is accompanied by hoarseness and impaired vocal function. Bilateral neuropathic paresis of the larynx leads to severe breathing disorders with the development of hypoxia and can cause asphyxia. Diagnostic measures for neuropathic paresis of the larynx include X-ray examination of the larynx, esophagus, chest organs; CT of the larynx and mediastinum; MRI and CT of the brain; Ultrasound of the heart and thyroid gland. Treatment of neuropathic paresis of the larynx consists in eliminating the factor that caused damage to the nerves innervating the larynx, using neuroprotective agents, conducting phonopedic and vocal exercises in the recovery period.

General information

The innervation of the internal laryngeal muscles is carried out by the branches of the vagus nerve. The anterior cricoid muscle is innervated by the superior laryngeal nerve, the remaining muscles of the larynx - the recurrent nerves. Various injuries or pathological conditions of the vagus nerve and its branches lead to the development of peripheral neuropathic paresis of the larynx. With damage to the nucleus of the vagus nerve in the brain stem or located above the pathways and cortical centers, central neuropathic paresis of the larynx occurs.

Neuropathic laryngeal paresis is the most common type of laryngeal paresis. It can be associated with pathology of the larynx, various diseases of the nervous system, pathological processes in the chest cavity. Therefore, not only otolaryngology, but also neurology and thoracic surgery are involved in the examination and treatment of patients with neuropathic laryngeal paresis.

Causes of neuropathic laryngeal paresis

Peripheral neuropathic paresis of the larynx is most often caused by the pathology of the right and left recurrent nerves. The large length of the recurrent nerve, its entrance to the larynx from the thoracic cavity and contact with many anatomical structures provide ample opportunities for nerve damage in its various parts. The left recurrent nerve bends around the aortic arch and can be compressed by an aneurysm. The right recurrent nerve runs at the apex of the right lung and can be trapped by pleural adhesions in this area. The causes of damage to the recurrent nerves with the development of neuropathic paresis of the larynx can also be: trauma of the larynx, pleurisy, pericarditis, tumors of the pleura and pericardium, lymphadenitis, tumors and cysts of the mediastinum, enlargement of the thyroid gland (with diffuse toxic goiter, autoimmune thyroiditis, iodine deficiency, tumor deficiency diseases), thyroid cancer, benign tumors, diverticula and esophageal cancer, tumors and enlargement of cervical lymph nodes.

Peripheral neuropathic paresis of the larynx can be of toxic origin and arise as a result of toxic neuritis of the recurrent nerves in case of poisoning with arsenic, alcohol, lead, nicotine, etc. It may develop in diabetes mellitus, as a result of intoxication with certain infections, for example, with diphtheria, typhus or typhoid fever , tuberculosis. The occurrence of neuropathic paresis of the larynx can be observed when the recurrent nerve is damaged during operations on the thyroid gland: thyroidectomy, hemithyroidectomy, subtotal resection.

Central neuropathic paresis of the larynx can be observed with damage to the brain stem (bulbar palsy), which is noted in tumors, neurosyphilis, poliomyelitis, botulism, syringomyelia, severe atherosclerosis of the cerebral vessels, hemorrhage in the brain stem in hemorrhagic stroke. Also, neuropathic paresis of the larynx of central origin is noted in pathological processes affecting the corresponding pathways and the cerebral cortex. Cortical neuropathic paresis of the larynx occurs in brain tumors, hemorrhagic and ischemic stroke, and severe traumatic brain injury. It should be noted that cortical neuropathic paresis of the larynx is always bilateral in nature, due to the incomplete intersection of the conducting nerve pathways before they enter the brain stem.

Symptoms of neuropathic laryngeal paresis

Decreased mobility of the vocal cords with neuropathic paresis of the larynx leads to impaired voice formation (phonation) and respiratory function. For neuropathic paresis of the larynx, the sequential involvement of the internal laryngeal muscles in the pathological process is characteristic: first, the function of the posterior cricoid muscle, which is responsible for the expansion of the glottis and the abduction of the vocal folds, is disrupted, then weakness and paralysis of the laryngeal adductors develops, which normally narrow the larynx and reduce the vocal cords ... This phenomenon is called the Rosenbach-Semon law. In accordance with it, with neuropathic paresis of the larynx, due to the operability of the adductors preserved at the beginning of the disease, the vocal cord on the side of the lesion occupies a middle position, after a while the weakness of the adductors increases and the vocal cord moves into an intermediate position.

Unilateral neuropathic paresis of the larynx at the beginning is characterized by the preservation of phonation due to the adjoining of the healthy vocal cord to the ligament of the affected side occupying the middle position. Breathing also remains normal, its difficulty can be detected only with significant physical exertion. The further development of neuropathic paresis of the larynx is accompanied by the involvement of the laryngeal adductors and the intermediate position of the vocal cord, due to which there is no complete closure of the glottis during phonation. Hoarseness of the voice occurs. After a few months, patients with neuropathic paresis of the larynx develop compensatory hyperadduction of the vocal cord on the healthy side and it begins to adhere more closely to the paretic ligament. As a result, the normal sounding of the voice is restored, however, disorders of the vocal function in patients with neuropathic paresis of the larynx persist.

Bilateral neuropathic paresis of the larynx in the initial period is accompanied by severe respiratory disorders up to asphyxia. This is due to the fact that both vocal cords are in a middle position and can completely close, preventing the passage of air into the respiratory tract. Clinically, bilateral neuropathic paresis of the larynx is manifested by rare noisy breathing with retraction of the supraclavicular fossa, epigastrium and intercostal spaces on inspiration and their protrusion on expiration. A patient with bilateral neuropathic paresis of the larynx is in a forced position, often sitting, resting his hands on the edge of the sofa. His facial expression reflects extreme fright, the skin is cyanotic in color. Even a slight physical effort causes a sharp deterioration in the condition. After 2-3 days from the onset of clinical manifestations of neuropathic paresis of the larynx, the vocal cords take an intermediate position and a gap is formed between them. Respiratory function improves, but any physical activity leads to symptoms of hypoxia.

Diagnostics of the neuropathic paresis of the larynx

The purpose of diagnosing neuropathic laryngeal paresis is not only to establish the diagnosis, but also to identify the cause of the paresis. For this, the patient is sent for a consultation

ICD-10 code: G52.2

On the side of the affected nerve, all internal (own) laryngeal muscles are paralyzed. If the external cricothyroid muscle, innervated by the external branch of the superior laryngeal nerve, remains active, it stretches the paralyzed vocal folds and takes them to the paramedian position.

With incomplete paralysis of the adductor muscles, paresis of the only abductor muscles of the vocal folds (posterior cricoid muscle) prevails in the picture of the lesion. This unilateral or bilateral form of paresis is known as posticus paresis. When observing patients with paralysis of the vocal folds, it is also advisable to use the stroboscopy method. If, during the observation process, fluctuations of the mucous membrane appear, then this indicates the beginning of the restoration of the function of the affected nerve, which is a favorable prognostic sign.

Unilateral recurrent nerve paresis

and) Symptoms and clinic... Recurrent nerve involvement is often diagnosed incidentally and manifests itself in the acute phase with moderate to severe dysphonia. Later, the voice is partially restored. Serious signs of airway obstruction are usually absent, appearing only with heavy exertion. Patients cannot play high notes or raise their voices.

b) Diagnostics... Laryngoscopy reveals an immobile vocal fold located in a paramedian or lateral position on one side. To establish the cause of the lesion, a complete laryngoscopic, phoniatric, neurological and X-ray examination is necessary.

in) Treatment... If the treatment of the disease that caused the paralysis of the vocal fold does not lead to the restoration of its function, voice therapy is carried out in order to restore the full closure of the vocal folds by activating the remaining neuromuscular units on the affected side and stimulating the mobile vocal fold on the opposite side.

Bilateral recurrent nerve paresis

and) Symptoms and clinic:
Dyspnea and threat of asphyxia due to narrowing of the glottis. With physical activity, during sleep or talking, an inspiratory stridor appears.
First, dysphonia appears, which has a different duration - from 4 to 8 weeks. depending on the cause of the lesion of the recurrent nerves. Subsequently, the voice becomes weak and hoarse. Speech is interrupted by long inspiratory phases.
A weak cough is also a characteristic symptom.

b) Causes and mechanisms of development are presented in the table below.

in) Diagnostics... The diagnosis is based on the results of laryngoscopy. With bilateral lesions of the recurrent laryngeal nerve, the vocal folds are located in the paramedian position.

d) Treatment of bilateral paralysis of the recurrent nerves:

Restoring a normal airway is of paramount importance. Tracheotomy and the introduction of a cannula with a spoken valve are used only for severe dyspnea, i.e. when the maximum expired airflow reaches below 40% of the patient's normal. Many patients manage to avoid tracheotomy by abstaining from physical activity, at rest they usually cope with dyspnea.

If spontaneous remission does not occur, surgical expansion of the epiglottis is indicated. It can be done in 10-12 months. after the appearance of a picture of paresis. The operation is resorted to in those patients who have persistent dyspnea and limited physical activity, or if, after an imposed tracheostomy, the patient wants to get rid of the speaking valve. Surgical correction is recommended by partial arytenoidectomy and posterior chordectomy.

Operation principles... The operation is performed endoscopically using a CO 2 laser. The part of the vocal process of the less mobile arytenoid cartilage, causing obstruction of the lumen of the lower cricoid ring, is resected (partial arytenoidectomy) and the elastic cone is dissected all the way to the cricoid cartilage. The posterior part of the vocal fold is dissected and part of the vocal muscle is resected (posterior chordectomy).

Lower part sublining mucosa sutured laterally to the bottom of the ventricle of the larynx (morgania ventricle) and the fold of the vestibule. The formation of a gaping gap in the posterior part of the glottis and the preservation of the anterior part of the vocal fold preserves contact of the vocal folds and the possibility of phonation.

P.S. The wider the gaping gap in the posterior part of the glottis after surgery, the worse phonation is restored.

Along with with surgical intervention the speech defect is corrected by restoring the voice at the level of the glottis or folds of the vestibule.