Laryngeal malformations: causes, symptoms, diagnosis, treatment

Laryngeal malformations are rare. Some of them are completely incompatible with life, for example, with laryngotracheopulmonary agenesis, atresia with complete obstruction of the larynx or trachea and bronchi. Other malformations are not so pronounced, but some of them can cause severe respiratory problems in the child immediately after birth, which require immediate surgical intervention to save his life. Such types of malformations include malformations of the epiglottis and its cysts, cysts of the vestibule of the larynx and its diaphragm. The most common are mild forms of malformations, which are detected at different times after birth, most often when the child begins to lead an active lifestyle associated with movement and development of vocal function. Sometimes the child adapts well enough to these malformations, and they are discovered by chance years later during a routine examination of the larynx. Such defects include split epiglottis or vocal folds, incomplete laryngeal diaphragms, etc. Other laryngeal defects are detected in the process of their gradual development in postnatal ontogenesis (cysts, etc.) due to the resulting disturbances of certain functions of the larynx. Among paralaryngeal developmental defects that can disrupt the functions of the larynx and cause its structural changes, it is necessary to note developmental defects of the thyroid gland, laryngopharynx, etc.

Laryngoptosis. This defect is characterized by a lower position of the larynx than normal: the lower edge of the cricoid cartilage may be at the level of the manubrium of the sternum; cases of laryngoptosis have been described when the larynx was located entirely behind the sternum, when the upper edge of the thyroid cartilage was at the level of its manubrium. Laryngoptosis may be not only a congenital, but also an acquired defect that develops either as a result of the traction action of scars that arise from lesions of the trachea and surrounding tissues, or from tumors that press on the larynx from above.

Functional disorders in congenital laryngoptosis are manifested only by an unusual timbre of the voice, which is assessed as an individual feature of a given person, while acquired forms cause atypical changes in the voice function, which are often accompanied by breathing disorders. Laryngoscopy does not reveal any structural endolaryngeal changes in the larynx in normal laryngoptosis.

Diagnosis of laryngoptosis is not difficult; the diagnosis is easily established by palpation, during which the pomum Adami can be located in the area of the jugular notch, but is not determined in a typical place.

Treatment for congenital laryngoptosis is not required, while secondary laryngoptosis, especially in combination with laryngeal obstruction, often requires tracheotomy, which in such patients is often complicated by subcutaneous and mediastinal emphysema, pneumothorax, or stenosis of the subglottic space.

Developmental defects of the thyroid cartilage are very rare. The most significant of them is the splitting of its ventral part, combined with dystopia of the vocal folds (increased distance between them and their location at different levels). The most common defect is the absence of the upper horns of the thyroid cartilage. In other cases, these formations can reach significant sizes, reaching the hyoid bone, with which each of them can form a supernumerary laryngeal joint. There are also asymmetries in the development of the plates of the thyroid cartilage, which is accompanied by a change in the position and shape of the vocal folds, ventricles of the larynx, and other endolaryngeal developmental defects, which entail certain timbre features of the voice function. The respiratory function of the larynx does not suffer. No treatment is carried out for these defects.

Developmental defects of the epiglottis are observed more frequently than the defects noted above. They include defects of shape, volume and position. The most common defect is splitting of the epiglottis, which can occupy only its free part or extend to its base, dividing it into two halves.

Among the malformations of the epiglottis, changes in its shape are most common. Due to the structure of the elastic cartilage, the epiglottis in an infant in the first years of life is more flexible and soft than in adults, due to which it can acquire a variety of shapes, for example, with a curved anterior edge, which is sometimes observed in adults. However, the most common is an epiglottis in the form of a groove with upwardly curved lateral edges, converging along the midline and narrowing the epiglottic space. In other cases, horseshoe-shaped or Щ-shaped epiglottis are observed, flattened in the anteroposterior direction.

Malformations of intralaryngeal structures. These malformations occur as a result of impaired resorption of mesenchymal tissue filling the lumen of the larynx during the first 2 months of embryonic development. With a delay or absence of resorption of this tissue, partial or total laryngeal atresia, circular cylindrical stenosis and, most often, laryngeal membranes - complete or partial, located between the vocal folds and called the laryngeal diaphragm may occur.

The laryngeal diaphragm is usually located in the anterior commissure and has the appearance of a sickle-shaped membrane that pulls together the edges of the vocal folds. The thickness of the laryngeal diaphragm varies, most often it is a whitish-grayish or grayish-reddish thin membrane that stretches during inhalation and gathers into folds during phonation. These folds prevent the vocal folds from coming together and give the voice a rattling character. Sometimes the diaphragm of the larynx is thick, and then the vocal function is impaired more significantly.

The laryngeal diaphragms may have different areas, occupying from 1/3 to 2/3 of the laryngeal lumen. Depending on the size of the diaphragm, respiratory failure of varying degrees develops, up to asphyxia, which often occurs even with moderate stenosis against the background of colds of the larynx or its allergic edema. Small laryngeal diaphragms are discovered accidentally in adolescence or adulthood. Subtotal or total forms are detected immediately or in the first hours or days after birth as a result of the occurrence of respiratory disorders: in acute cases - the appearance of signs of asphyxia, with an incomplete diaphragm - noisy breathing, sometimes cyanosis, constant difficulty in feeding the child.

The diagnosis in newborns is established by signs of mechanical obstruction of the larynx and by direct laryngoscopy, during which the doctor must be prepared for immediate perforation of the diaphragm or its removal. Therefore, direct laryngoscopy must be prepared as a microendolaryngological surgical intervention.

Treatment for laryngeal diaphragms involves incision or excision of the membrane with subsequent bougienage with a hollow bougie to prevent laryngeal stenosis. In more severe congenital fibrous stenosis, after tracheotomy, the thyroid cartilage is incised (thyrotomy) and, depending on the degree and localization of the scar tissue, appropriate plastic surgery is performed, similar to those used for acquired cicatricial stenosis of the larynx. In adults, a laryngostomy is most often formed for more effective postoperative care of the laryngeal cavity, since it is often necessary to stop the emerging granulations, reposition the skin or mucous plastic flap covering the wound surfaces, perform toilet and treat the larynx with antiseptics. Plastic flaps are fixed to the underlying tissues using a dummy made of elastic spongy material or an inflatable balloon, which is changed daily. If the flaps are well-grafted and there is no granulation tissue, the laryngostomy is closed plastically, with the dilator balloon left in it for 2-3 days, then it is removed using a thread tied to it and brought out through the tracheostomy. Instead of an inflatable balloon, an A.F. Ivanov tee can be used.

In children, surgical removal of the membrane is performed only in the case of obvious signs of respiratory failure, which is an obstacle to the normal physical development of the body and a risk factor for the development of acute asphyxia during colds. In all other cases, surgical treatment is postponed until the larynx is fully developed, i.e. until 20-22 years of age. In the case of complete or subtotal diaphragm of the larynx, the life of the newborn can be saved only by immediate perforation of the membrane, which can be performed with a 3 mm laryngoscope or, under appropriate conditions, by tracheotomy.

Congenital laryngeal cysts occur much less frequently than acquired cysts, which occur during postnatal ontogenesis as a result of certain laryngeal diseases (retention, lymphogenous, posttraumatic, etc.). Sometimes congenital laryngeal cysts grow intensively during fetal development and reach significant sizes, resulting in asphyxia and death immediately after birth. In other cases, these cysts develop more or less slowly, causing respiratory distress or swallowing difficulties during feeding. A true cyst is a cavity whose walls include virtually all layers of epidermoid formations: its cavity contains a lining of multilayered squamous epithelium with varying degrees of keratosis, deflated epithelium, and cholesterol crystals. There is a connective tissue layer under the epidermis, and the cyst is covered with the mucous membrane of the larynx on the outside.

Most congenital laryngeal cysts manifest themselves with some signs of laryngeal dysfunction between the 3rd and 15th months after birth. Among these disorders, the most characteristic is laryngeal stridor. Respiratory disorders caused by congenital laryngeal cysts increase gradually, while disorders arising due to malformations of the epiglottis gradually decrease as the ligamentous and cartilaginous apparatus consolidates and the intralaryngeal muscles strengthen.

Cysts usually arise in the area of the entrance to the larynx, from where they spread downwards, filling the pyriform sinuses, laryngeal ventricles and inter-laryngeal space, penetrating the aryepiglottic folds. Congenital cysts are often localized on the vocal fold.

A type of congenital laryngeal cyst is the so-called groove (a narrow notch on the surface of the vocal fold parallel to its free edge). This cyst is easily detected only by stroboscopy, in which it is revealed during phonation by its rigidity and vibration separate from the true vocal fold.

The diagnosis is established by direct laryngoscopy, during which it is possible to puncture the cyst, open it, partially remove its wall and thus prevent asphyxia of the infant. In case of large cysts, its puncture is performed from the outside, through the skin, which prevents its infection.

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