Microtia means ‘small ear’. This term is applied to anyone who is born with an underdeveloped ear. Microtia occurs in approximately 1:6000 - 10000 births. Microtia occurs more often on the right side than the left and more often in males. The condition can affect one ear (unilateral) or both ears (bilateral). It is bilateral in approximately 10% of cases.
Children born with microtia have a varying degree of ear malformation. In most cases there is a vertical skin appendage with a small lobule (ear lobe) on the lower end. In others the hollow of the ear may partly be formed with the ear lobe. The most severe form of microtia is complete absence of the ear, known as anotia.
Microtia photo gallery
Microtia can occur as an isolated deformity or present as part of a spectrum of other defects. Any child born with microtia should be evaluated to rule out other conditions. Microtia is known to occur as part of a several of syndromes, especially hemifacial microsomia, Goldenhar syndrome and Treacher-Collins syndrome.
Hearing in microtia
The external auditory canal is generally absent in microtia. Associated with the absence of the external canal are deformities within the middle ear and absence of the tympanic membrane. For these reasons, children with microtia have varying degrees of hearing loss (approximatley 40%). Hearing occurs via bony conduction ie sound travels through akin and bone of the skull to the inner ear. Most children with microtia have a normally formed inner ear. Children with unilateral microtia usually do not require a hearing aid. In children with bilateral microtia hearing is typically reduced by 40% on both sides. These children should be fitted with a hearing aid at an early age.
What causes microtia?
There is a rare hereditary pattern for microtia. Studies have shown that in 5% of patients a member of the immediate family has an ear abnormality. There is no specific gene that has been identified and genetic counselling is generally not recommended.
There is some experimental evidence that there is an interruption of blood supply to the ear during its development. It has also been suggested that some medications may lead to this condition, but this is extremely hard to prove. In conclusion, all current evidence suggests that many complicated factors lead to microtia, and there is nothing that the mother did wrong during pregnancy to cause this to happen.
Treatment
There are three options available:
- No treatment
In some cases the child and parents may feel that the ear abnormality has no negative effect on social interaction. In such cases the child does not experience low self -esteem related to the abnormality and thus personal development is not impeded.
- Prosthesis
These generally require the insertion of titanium pins in the bone to enable secure placement of the prosthesis, which is clipped on a metal bar crossing the pins. The prosthesis rarely matches the tone of the skin. It will need to be removed daily for cleaning and may be unclipped by minor trauma. A significant number of patients have minor problems around the pins. If a patient opts for prosthesis then it becomes very difficult to have ear reconstruction at a later date.
- Ear reconstruction
This is highly specialised surgery offered by few surgeons who specialise in this field.
