Anomalies in the development of the external ear
According to the World Health Organization, up to 15% of children are born with obvious signs of various developmental anomalies. However, congenital anomalies may appear later, so the overall frequency of malformations is much higher. It is established that in children born to mothers of older age, anomalies occur more often, because the older a woman, the greater the amount of harmful environmental influences( physical, chemical, biological) on her body. The developmental anomalies in children born from parents with developmental anomalies occur 15 times more often than in children born from healthy parents.
Congenital malformations of the external and middle ear are found with a frequency of 1-2 cases per 10,000 newborns.
The inner ear appears already in the fourth week of embryo development. The middle ear develops later, and by the time the baby is born, the drum cavity contains a jelly-like tissue, which subsequently disappears. The external ear appears on the fifth week of intrauterine development.
In the newborn, the auricle may be enlarged( hypergenesis, macrocosmia) or reduced( hypogenesis, microtia), which is usually combined with infection of the external auditory canal. Only some of its parts( for example, earlobe) can be excessively enlarged or reduced. The developmental anomalies can be one-and two-sided and manifest in the form of ear appendages, several ears( polyotia).There are splitting of the lobe, congenital fistulas of the ear, atresia( absence) of the external auditory canal. The auricle may be absent, occupy an unusual place. In microtia, it can be located in the form of a rudiment on the cheek( buccal ear), sometimes only the earlobe or the skin-cartilaginous roller with the lobe are retained.
The auricle is coagulated, flat, ingrown, corrugated, angular( ear of macaque), pointed( satyr's ear).The auricle can be with a transverse cleft, and the lobe with a longitudinal one. Other defects of the lobe are known: it can be prirosshey, large, lagging. Combined forms of external ear defects are common. Often, anomalies in the development of the auricle and the external auditory canal are combined in the form of its partial underdevelopment or total absence. Similar anomalies are described in the form of syndromes. So, the developmental defect of connective tissue, in which many organs, including the ears, are affected, is called Marfan syndrome. There are congenital deformities of both auricles in members of the same family( Potter's syndrome), bilateral microtia among members of the same family( Kessler's syndrome), ophthalmic-otic dysplasia( Goldenhar syndrome).
In macroscopy( an increase in the size of the auricle), taking into account the variety of changes, a number of surgical procedures have been proposed. If, for example, the auricle is enlarged evenly in all directions, that is, it has an oval shape, the excess tissue can be excised. Operations to restore the auricle in its absence are quite complex because the skin is needed, and it is necessary to create an elastic skeleton( support) around which the auricle is formed. To form the skeleton of the auricle, cartilage of the rib, cartilage of the auricle of the corpse, bone and synthetic materials are used. Ear pendants, located near the auricle, are removed together with the cartilage.
Among the anomalies in the development of the external auditory canal, its atresia( more often in combination with the anomaly of the development of the auricle), constriction, bifurcation and closure of the membrane are observed.