Paralysis of the larynx (paresis of the larynx) - Causes and pathogenesis

Paralysis of the larynx - disorder of motor function in the form of the complete absence of voluntary movements due to a violation of the innervation of the corresponding muscles. Paresis of the larynx - reduction of strength and (or) amplitude of voluntary movements, due to a violation of innervation of the corresponding muscles, implies a temporary (up to 12 months) impaired mobility of one or both halves of the larynx.

Among chronic diseases of the vocal apparatus, laryngeal paralysis takes second place and is 29.9%. Paralysis of the larynx, depending on the level of damage is divided into central and peripheral, one-and two-sided.

Etiology. Paralysis of the larynx is a polyetiological disease. It may be due to the compression of the structures that innervate it or the involvement of nerves in the pathological process that develops in these organs, their traumatic injury, including during surgical interventions on the neck, chest, or skull.

Paralysis of central origin depending on the topography of the lesion in relation to nucleus ambiguus conventionally divided into supranuclear (cortical and corticobulbar) and bulbar ones. Cortical paralysis is always bilateral in accordance with innervation from the motor nucleus, their possible causes are contusion, congenital cerebral palsy, encephalitis, bilirubin encephalopathy, diffuse cerebral arteriosclerosis. Corticosteriasis paralysis may occur as a result of damage to the area of ​​the crossroads of the cortico-vulvar tract (for example, in the case of circulatory failure of the vertebral artery, occlusion of the latter). Bulbar palsy can be a consequence of impaired blood circulation in the basins of the vertebral, posterior and anterior lower cerebellar, upper, middle, lower lateral branches of the cerebellar arteries, as well as polysclerosis, syringobulbia, syphilis, rabies, polio, intracerebral tumors. For the development of symptoms of paralysis of the larynx is enough partial damage to the nucleus. Paralysis of the larynx of central Genesis is approximately 10% of cases.

The main causes of peripheral laryngeal paralysis:

  • • medical injury during surgery on the neck and chest,
  • • compression of the nerve trunk over due to a tumor or metastatic process in the neck and chest, tracheal or esophagus diverticulum, hematoma or infiltrate with injuries and inflammatory increase in the size of the heart and aortic arch (Fallot tetrade, mitral defect, aortic aneurysm, ventricular hypertrophy, pulmonary artery dilatation),
  • • neuritis of inflammatory, toxic or metabolic genesis (viral, toxic, poisoning by barbiturates, organophosphates and alkaloids), hypocalcemic, hypokalemic, diabetic, thyrotoxic.

The most common cause of paralysis is a pathology of the thyroid gland and a medical injury during operations on it. With the primary intervention, the complication rate is 3%, with the second one - 9%, with the surgical treatment of thyroid cancer - 5.7%. In 2.1% of patients, paralysis is diagnosed at the preoperative stage.

Pathogenesis. With laryngeal paralysis, all three of its functions suffer. The severity of clinical symptoms and morphofunctional changes of the larynx depends on the degree of denervation and the nature of compensatory-adaptive changes, the position of the paralyzed vocal fold, the development of atrophic processes in the muscular system of the larynx, the condition of the cricoid joint. The severity of the disease in case of unilateral paralysis is caused by the lack of a gap in the glottis, and in a bilateral one, by the median position of the vocal folds, leading to stenosis of the larynx.

The respiratory tract is protected from aspiration during swallowing with several reflex mechanisms, including the movement of the larynx upward and its inclination towards the front, the adduction of the vocal folds, coordination of breathing and swallowing. Such protection is impaired with paralysis of the larynx, especially in the early stages of its development. Normally, the rise of the larynx when swallowing is accompanied by the closure of the glottis. In patients with laryngeal paralysis, this does not occur, the intact vocal fold occupies a more elevated position. Compensation of lost functions in case of one-sided paralysis of the larynx is carried out by changing the voltage of the adductors, forcing the voice to increase the sub-loading pressure, and changing the configuration of the packing space. Clinically, this is expressed by the displacement of the glottis during phonation to the side, hypertrophy of the vestibular folds. With bilateral paralysis of the larynx with an intermediated position of the vocal folds over time, they shift to the midline with the development of laryngeal stenosis.

Clinical picture. Paralysis of the larynx is characterized by immobility of one or both of its halves. Violation of innervation entails serious morphofunctional changes - the respiratory, protective and vocative functions of the larynx suffer.

Paralysis of central genesis is characterized by impaired mobility of the tongue and soft palate, changes in articulation.

The main complaints for unilateral paralysis of the larynx:

  • • hoarseness of varying severity,
  • • shortness of breath, aggravated by voice load,
  • • gagging
  • • foreign body sensation on the affected side.

With bilateral paralysis of the larynx, the clinical symptoms of stenosis come to the fore.

The severity of clinical symptoms and morphofunctional changes in the larynx during paralysis depends on the position of the paralyzed vocal fold and the duration of the disease. There are median, paramedian, intermediary and lateral position of the vocal folds.

In the case of unilateral laryngeal paralysis, the clinical picture is most striking in the lateral position of the paralyzed vocal fold. With a median position, the symptoms may be absent, the diagnosis is established randomly at the dispensary examination. Such paralysis of the larynx is 30%. For a bilateral lesion with lateral fixation of the vocal folds, aphonia is characteristic. Respiratory failure develops according to the type of hyperventilation syndrome, possibly a violation of the separation function of the larynx, especially in the form of choking with liquid food. In case of bilateral paralysis with paramedian, intermediary position of the vocal folds, impairment of respiratory function is observed, up to laryngeal stenosis of the III degree, requiring immediate surgical treatment. It should be remembered that in case of bilateral lesion, the respiratory function is worse, the better the patient's voice.

Fig. 141. The position of the left paralyzed vocal fold during phonation: 1 - the laryngoscopic picture is normal, 2 - median, 3 - paramedian,

4 - intermediate, 5 - lateral

The severity of clinical symptoms depends on the duration of the disease. In the first days, there is a violation of the separation function of the larynx, shortness of breath, significant hoarseness, foreign body sensation in the throat, and sometimes a cough. Later on, on the 4-10th day and later, there is an improvement due to partial compensation of the lost functions. However, in the absence of therapy, the severity of clinical manifestations may increase with time due to the development of atrophic processes in the muscles of the larynx, worsening the closure of the vocal folds.

Diagnostics. The high incidence of laryngeal paralysis of a tumorous nature necessitates a thorough examination of patients in order to detect malignant tumors. In evaluating the history, attention is paid to the duration of the disease, since this affects the tactics of treatment.

All patients with laryngeal paralysis of unclear genesis are examined according to the following algorithm:

• x-ray or computed tomography of the larynx and trachea,

  • • x-ray or computed tomography of the chest and mediastinum,
  • • esophageal radiography with contrast barium sulfate solutionwhich can be supplemented with endofibroosophagoscopy,
  • • thyroid gland ultrasound, consultation of an endocrinologist,
  • • MRI of the brain in the presence of neurological symptoms or suspected central paralysis, consultation with a neurologist.

Clinical and functional state of the larynx is determined by the indicators of the function of external respiration, micro-laryngoscopy and micro-lingrostroboscopy, acoustic voice analysis. Apply electromyography and glottography.

With unilateral paralysis of the larynx, differential diagnosis is carried out with the immobility of the vocal fold due to the pathology of the cricoid joint, including dislocation, subluxation, arthritis and ankylosis. Signs of dislocation include the lack of symmetry in the joints, signs of inflammation in the joint, displacement of scarp-like cartilage, and restriction of mobility or complete immobility of the vocal fold on the side of damage. For arthritis, edema and hyperemia of the mucous membrane in the area of ​​the joint is characteristic.

Differential diagnosis of the pathology of the cricoid joint is performed using X-ray or computed tomography, by means of which the area of ​​the cricoid joint is well visualized, according to electromyography, by definition, electromagnetic resonance, reflecting the state of the internal spaces between the soft tissues. The method of endolaryngeal sounding of the joint probe is considered the most informative.

When conducting a differential diagnosis of paralysis of the larynx of unknown origin, consultations of an endocrinologist, a neurologist, a pulmonologist are shown.

Treatment. The goal of treatment is to restore the mobility of laryngeal elements or to compensate for lost functions (breathing, swallowing and voice). Etiopathogenetic and symptomatic therapy is carried out (Table 7). Treatment begins with the elimination of the cause of the immobility of half of the larynx (for example, nerve decompression). Then detoxification and desensitization therapy is carried out in case of damage to the nerve trunk of an inflammatory, toxic, infectious or traumatic nature.

Fig. 142The method of sensing the cricoid joint

Table 7. Treatment methods for laryngeal paralysis

Nerve decompression (removal of a tumor, scar, removal of inflammation in the damaged area) De-on-detoxification therapy (desensitizing, anti-edematous and antibiotic therapy) Improving nerve conduction and preventing neurodystrophic processes (, triphosphadenine, vitamin complexes, acupuncture)

Improved synaptic conduction (neostigmine methyl sulphate)

Stimulation of regeneration in the damage zone (electrophoresis and medical-drug blockade neostigmine by metipsupfat, pyridoxine, hydrocortisone)

Stimulation of nervous and muscular activity, reflexogenic zones Mobilization of the scyphoid joint Surgical methods (laryngeal reinnervation, laryngotracheoplasty)

Electrical stimulation of the nerves and muscles of the larynx

Surgical methods (TIRO, laryngoplasty, implant surgery, tracheostomy)

Effective use of physiotherapy treatment - electrophoresis of the larynx, electrical stimulation of the muscles of the larynx. External methods are used — direct effects on the muscles of the larynx and nerve trunks, electrical stimulation of the reflexogenic zones with diadynamic currents, endolaryngeal electrical stimulation of the muscles with galvanic and faradic currents, as well as anti-inflammatory therapy.

Of great importance is the holding of respiratory gymnastics and phonopedy. The latter is used at all stages of treatment and for any period of the disease, for any etiology.

When neurogenic paralysis of the vocal fold, regardless of the etiology of the disease, immediately begin treatment aimed at stimulating the nerves on the affected side, as well as on the cross and residual innervation of the larynx. Apply drugs that improve the nervous, synaptic conductivity and microcirculation, slowing neurodystrophic processes in the muscles.

Methods of surgical treatment of unilateral laryngeal paralysis:

  • • reinnervation of the larynx,
  • • thyrooplasty,
  • • implant surgery.

Surgical reinnervation of the larynx is performed by neuro-, myo-, neuromuscular plastics. A wide variety of clinical manifestations of laryngeal paralysis, the dependence of the results of the intervention on the prescription of denervation, the degree of atrophy of the internal muscles of the larynx, the presence of concomitant pathology of cartilage cartilage, various individual features of nerve fiber regeneration, the presence of synkinesis and poorly predicted distortion of the larynx innervation with the formation of scars in the area of ​​operation limit the use of this techniques in clinical practice.

Of the four types of thyroplasty, paralysis of the larynx applies the first (medial displacement of the vocal fold) and the second (lateral displacement of the vocal fold). In the case of thyrooplasty of the first type, in addition to the medialization of the vocal fold, the scaly-shaped cartilage is displaced laterally and fixed with sutures using a window in the plate of the thyroid cartilage. The advantage of this method is the ability to change the position of the vocal fold, not only in the horizontal, but also in the vertical plane. The use of such a technique is limited when fixing the scapular cartilage and muscle atrophy on the side of paralysis.

The most common method of medialisation of the vocal fold in unilateral paralysis of the larynx is implant surgery. Its effectiveness depends on the properties of the implantable material and the method of its introduction. The implant should have good tolerance to absorption, fine dispersion, providing easy insertion, have a hypoallergenic composition, not cause pronounced productive tissue reaction and not have carcinogenic properties. Teflon, collagen, auto fat, etc. are used as an implant. Methods of material injection into the paralyzed vocal fold are anesthetized with direct microlaryngoscopy, under local anesthesia, endolaryngeally and percutaneously. G.F. Ivanchenko (1955) developed a method of endolaryngeal fragmented teflon-collagenplasty: teflon paste is introduced into the deep layers, which forms the basis for the subsequent plastics of the outer layers.

Among the complications of implant surgery, note:

  • • acute laryngeal edema,
  • • granuloma formation,
  • • migration of teflon paste to the soft tissues of the neck and thyroid gland.

Methods of surgical treatment of bilateral paralysis of the larynx. Currently, there are two main areas of laryngeal reconstructive surgery: laryngeal reconstruction and circular resection of the pathological area. The choice of method depends on the patient's indications and contraindications.

In each case, the amount of surgery is determined depending on the etiology of the underlying disease with the condition of maximum radical surgery. Myoaritenoidhordectomy with leverfixation of the opposite vocal fold, redressing of the persistent cartilage, the formation of structures of the larynx and trachea with the help of allohrashchayas are possible.

Treatment of paralysis of the larynx phased, consistent.In addition to medication, physiotherapy, and surgical treatment, patients were shown long-term exercises with phonopods, the purpose of which is to form correct phonon breathing and golosovedenie, correction of violations of the laryngeal separation function. Patients with bilateral paralysis should be observed 1 time in 3 or 6 months depending on the clinical manifestations of respiratory failure. Patients with laryngeal paralysis are shown to consult a phoniatrist to determine the possibilities of rehabilitating lost laryngeal functions, restoring voice and breathing as soon as possible.

With bilateral laryngeal paralysis, the patient’s ability to work is severely limited. With unilateral paralysis of the larynx (in the case of a profession related to the voltage of the vocal cords), disability is possible. However, when restoring the voice function, these restrictions can be removed.

For patients with unilateral laryngeal palsy, the prognosis is favorable, since in most cases it is possible to restore the voice and respiratory function (with some restrictions on physical exertion, since the restoration of the closure of the vocal folds results in the inhalation slit being half narrowed). Most patients with bilateral paralysis of the larynx require a step-by-step surgical treatment. If it is possible to carry out the entire course of rehabilitation treatment, decanulation and breathing through natural paths are likely, the voice function is partially restored.

Symptoms of laryngeal paralysis

  • Frequent gagging.
  • Hoarseness (or hoarseness, aggravated after crying in children) up to aphonia (complete loss of voice).
  • Dyspnea.
The severity of clinical symptoms depends on the position of the paralyzed vocal folds and the degree of damage to the larynx (unilateral or bilateral):
  • in some cases, the symptoms may be absent and the violation is detected by chance during a medical examination,
  • slight paresis (partial reduction of the force of voluntary movements of the larynx) or one-sided paralysis (disorder of the motor function of the larynx up to the complete absence of voluntary movements) is accompanied by pronounced hoarseness,
  • with bilateral paresis or paralysis to the forefront: severe shortness of breath, respiratory failure.
    The peculiarity is that in case of bilateral lesion the respiratory function is worse, the better the patient's voice.

A doctor ENT (otolaryngologist) will help in the treatment of the disease

Diagnostics

  • Analysis of complaints and anamnesis of the disease (nature of breathing, the presence of dyspnea, the presence of diseases or injuries (including operations, birth injuries) in the past (or present), contributing to the development of paralysis, etc.).
  • General examination (signs of respiratory failure, palpation of the neck).
  • Determining the cause of the development of pathology (radiation diagnosis (x-ray or computed tomography) of the larynx, trachea, chest or esophagus to identify pathologies (eg, tumors) that squeeze the branches of the vagus nerve that conduct nerve impulses to the structures of the larynx), especially when unilateral left-sided paresis.
  • Ultrasound examination of the thyroid gland (since thyroid pathology is one of the most frequent causes of the development of laryngeal paralysis).
  • Fibrolaryngoscopy (instrumental method of diagnosis of the larynx with a flexible endoscope). This method allows you to determine the degree of mobility of the larynx, the state of the vocal apparatus and closure of the glottis.
  • Video stroboscopy (method of studying the mobility of the vocal cords using intermittent light with the possibility of video surveillance).
  • Glottography is a method of studying the vocal apparatus by registering a curve representing the oscillation of the vocal folds in the process of phonation (speaking) to determine deviations in the conduction of a nerve impulse to the vocal apparatus.
  • Electromyography is a method for studying the neuromuscular system (in this case, in the larynx area) by registering the electrical potentials of the muscles in order to detect irregularities in the processes of the nerve impulse.
  • Consultation of a neurologist in the presence of neurological symptoms (for example, hearing loss, vision, slurred speech, etc.) is performed by computed or magnetic resonance imaging of the brain in order to avoid damage to brain structures responsible for the transmission of nerve impulses to the vagus nerve.

Treatment of laryngeal paralysis

Treatment depends on the severity of the disease and is aimed at restoring the motor function of the larynx.

  • Elimination of the cause of immobility of the larynx (i.e., treatment of a disease that caused the development of laryngeal paralysis). For example, detoxification therapy in cases of toxic nerve damage in the background of an infectious process.
  • Observance of voice rest - with the infectious nature of paralysis, with myopathic paresis.
  • The appointment of drugs that improve the conductivity of nerve impulses and microcirculation.
  • Physical therapy (for example, electrical stimulation of the muscles of the larynx).
  • Breathing exercises.
  • Acupuncture.
  • Phonopedia is a complex of special exercises aimed at the gradual activation and coordination of the neuromuscular apparatus of the larynx.
  • Treatment of paralysis caused by trauma or surgery on the neck should be started as soon as possible (in 1-2 weeks), in case of delay in treatment, muscle atrophy is possible (irreversible loss of motor function).
  • With the ineffectiveness of the conservative treatment of unilateral paralysis and the retention of pronounced voice disorders, an operation is carried out aimed at bringing the affected fold closer to the midline.
  • Hospitalization - with the development of laryngeal stenosis.
  • In critical conditions (with the development of asphyxiation), a tracheotomy is performed (the essence of the procedure is to form an incision on the front surface of the neck and insert a tube into the airway cavity through which the patient can breathe).
  • For bilateral paralysis and respiratory failure, surgical treatment is performed to avoid permanent wearing of the tracheostomy (for example, the vocal fold is removed with the adjacent cartilage on one side, or one vocal fold is fixed in the lateral position). This adversely affects the voice, but significantly improves the respiratory function. Phonopedic exercises after surgery help to restore a few voice.

Complications and consequences

  • Stenosis of the larynx (narrowing of the lumen of the larynx until complete obstruction, and therefore the respiratory function is impaired).
  • Against the background of stenosis of the larynx, chronic hypoxia (oxygen starvation) develops and, as a result, impaired functioning of vital organs (nervous system, cardiovascular, etc.).
  • The development of acute and chronic inflammatory diseases of the bronchi and lungs.
  • With the existing stenosis, any respiratory infection can lead to decompensation (that is, the inability of the body to “adapt” to the conditions of the existing pathology), which is fatal.
  • Ankylosis (immobility) of scapular cartilage (one of the structures of the vocal apparatus), which leads to a persistent disruption of the vocal function, up to a complete loss of voice,
  • Aspiration during swallowing (sputum and saliva, food in the respiratory tract).
  • Persistent violations of the vocal function until the complete loss of voice.

Prevention of laryngeal paralysis

  • Timely recognition and treatment of pathologies that may lead to the development of paralysis of the larynx (tumor processes, acute inflammation of the upper respiratory tract).
  • Timely treatment of injuries of the larynx and cricoid joint.
  • A gentle approach (that is, compliance with all measures to prevent injury to the larynx) during thyroid surgery.
  • Avoid inhalation of acrid smoke, alkalis or acids in the respiratory tract.
  • Timely and complete treatment of viral and bacterial infectious diseases.
  • To avoid prolonged intubation (imposition of the endotracheal tube in the lumen of the larynx and trachea), according to various sources, no more than 3-5-7 days).
  • Laryngoscopy for persons with prolonged hoarseness, before and after surgery to remove the thyroid gland, prolonged intubation, or surgery on the neck and chest to timely detect signs of paralysis of the larynx.
  • In case of peripheral paralysis, start treatment without delay, immediately after the diagnosis.
  • For persons of vocal and speech professions - avoid excessive or inadequate voice loads, observe voice hygiene:
    • avoid eating too cold, spicy, sour, salty or hot foods,
    • avoiding alcohol and smoking
    • timely treatment and prevention of colds.

INFORMATION FOR READING

Consultation with a doctor is necessary.

National Guide to Otolaryngology, edited by V.T. Palchun 2008
DIRECTORY ON OTORINOLARYNGOLOGY, AG Likhachev, due to “Me d i t and n a” 1984
Stenosis of the larynx in children M. R. Bogomilsky et al. Bulletin of Otorhinolaryngology, №2, 2005

The clinical picture of laryngeal paralysis

To compile a complete picture of the characteristics of the patient’s condition, establish an accurate diagnosis and correct treatment, it is important to take into account all the patient’s complaints, the course of the disease and its specific characteristics. The lumen level of the larynx can be easily determined during a general thorough examination of the patient, as well as after carrying out the necessary general examination.

With paralysis of the larynx, the voice, respiratory and protective functions of the throat are greatly impaired. The voice is sonorous, sometimes aspirated hoarseness is noticed. The disorder of the respiratory tract function matures when there is a mismatch between the size of the glottis and the physical structure of a person, with excessive weight, good physical exertion, chronic laryngitis, acute respiratory infections and various lung diseases.

Often, the patient has confused breathing, he feels apathy or, as opposed to apathy, anxiety. There are bluish spots on the fingers and face, shortness of breath even when calm and with little exertion, the patient breathes loudly and often. Along with this significantly increases blood pressure. Patients with acute stenosis of the throat have a more pronounced clinic than in a chronic one, although their glottis are more open.

If laryngeal paralysis occurs as a result of injury to the recurrent nerve during surgery, then within one and a half to two weeks this problem is treated with conservative methods, unless specific symptoms of acute respiration occur. Next, prescribe antibacterial drugs and effective hormone therapy. If hematomas are expressed, the necessary medicines are prescribed, which coagulate blood, as well as vitamin and vascular therapy.

Positive dynamics is an indication for the purpose of the course of special exercises. Until complete recovery, the patient should be observed by an otolaryngologist. After a full month of rehabilitation after surgery, if the patient has bilateral laryngeal paralysis, treatment is prescribed individually. The appointment takes into account the severity of respiratory failure, the size of the glottis, the key disease that accompanies pathology.

In order to normalize breathing as quickly as possible with the help of local anesthesia or anesthesia, an urgent tracheostomy is performed. As a rule, most patients with bilateral laryngeal paralysis need surgical intervention. The indications for such an operation are damage to the physical activity of the vocal cords, the inability to breathe naturally, the ineffectiveness of conservative treatment.

Do not recommend such operations to conduct patients with advanced age, those who have severe concomitant anomaly, diseases of the thyroid gland.

Expert Editor: Pavel Alexandrovich Mochalov | D.M.N. general practitioner

Education: Moscow Medical Institute. I. M. Sechenov, specialty - “Medicine” in 1991, in 1993 “Occupational diseases”, in 1996 “Therapy”.

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Medical expert articles

Causes of laryngeal paralysis (laryngeal paresis)

Paralysis of the larynx is a polyetiological disease. It may be due to a squeezed innervating structure or the involvement of nerves in the pathological process that develops in these organs, their traumatic injury, including during surgical interventions on the neck, chest, or skull.

Paralysis of central genesis, depending on the topography of the lesion in relation to the nucleus ambiguus, is conventionally divided into naduclear (cortical and corticobulbar) and bulbar ones. Cortical paralysis is always bilateral in accordance with innervation from the motor nucleus, possible m causes contusion, congenital cerebral palsy, encephalitis, bilirubin encephalopathy, diffuse atherosclerosis of cerebral vessels. Corticopulmonary paralysis may occur as a result of damage to the area of ​​the corticobulbral tract, such as insufficient blood circulation in the vertebral artery pool, the occlusion of the latter. Bulbar palsy may be a consequence of impaired blood circulation in the basins of the vertebral, posterior and anterior lower cerebellar, upper, middle, lower lateral branches of the cerebellar arteries, as well as polyscleroa, syringobulbia, syphilis, rabies, encephalitis, polio, intracerebral tumors. For the development of symptoms of paralysis of the larynx is enough partial damage to the nucleus. Paralysis of the larynx of central Genesis is approximately 10% accidental. The main causes of peripheral laryngeal paralysis:

  • medical injury during surgery on the neck and chest,
  • compression of the nerve trunk during a tumor or metastatic process in the neck and chest, tracheal or esophagus diverticulum, hematoma or infiltrate with injuries and inflammatory processes, with an increase in the size of the heart and aortic arch (Fallot tetrade), mitral defect, aortic aneurysm, ventricular hypertrophy, pulmonary dilatation),
  • neuritis of inflammatory, toxic or metabolic genesis (viral, toxic (poisoning with barbiturates, organophosphates and alkaloids), hypocalcemic, hypokalemic, diabetic, thyrotoxic).

The most common cause of paralysis is a pathology of the thyroid gland and a medical injury during operations on it. With the primary intervention, the complication rate is 3%, with the second one - 9%, with the surgical treatment of thyroid cancer - 5.7%. In 2.1% of patients, paralysis is diagnosed at the preoperative stage.

Pathogenesis of laryngeal paralysis (larynx paresis)

With laryngeal paralysis, all three functions of the larynx suffer. The severity of clinical symptoms and morphofunctional changes in the larynx depends on the degree of denervation and the nature of compensatory-adaptive changes, the position of the paralyzed vocal fold, the development of atrophic processes in the muscular system of the larynx, and the state of the cricoid joint. The severity of the disease in case of unilateral paralysis is caused by the lack of a gap in the glottis, and in bilateral paralysis, on the contrary, by the middle position of the vocal folds, resulting in stenosis of the larynx.

The timing of the onset of laryngeal muscle atrophy is not precisely defined, is individual and depends on the degree of denervation and the removal of the vocal fold from the midline. Atrophy of the vocal fold worsens the course of unilateral paralysis of the larynx, as it leads to its additional lateralization and decrease in tone. Carrot-like cartilages on the side of the paralysis are often shifted to the healthy side, rotated anteriorly. The results of electromyographic studies prove that complete denervation of the vocal fold with muscular atrophy during laryngeal paralysis develops infrequently, in most cases any level of synkinesis and reinnervation is diagnosed. With a long-existing paralysis, ankylosis of the scyphoid joint occurs, which is detectable during probing.

The respiratory tract is protected from aspiration during swallowing with several reflex mechanisms, including movement of the larynx upwards and tilting it forward, adduction of the vocal folds, coordination of breathing and swallowing. Such protection is impaired with paralysis of the larynx, especially in the early stages of its development and in normal laryngeal elevation during swallowing, accompanied by the closure of the glottis. In patients with laryngeal paralysis, this does not occur, the intact vocal fold occupies a more elevated position. Compensation of lost functions in case of one-sided paralysis of the larynx is carried out by changing the voltage of the adductors, forcing the voice to increase the sub-loading pressure, and changing the configuration of the packing space. Clinically, this is reflected in the displacement of the glottis during phonation towards paralysis due to the movement of the healthy vocal fold to the opposite side, hypertrophy of the vestibular folds. In case of bilateral paralysis of the larynx with an intermediated position of the vocal folds, more often with time, they shift to the midline with the development of laryngeal stenosis.

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