Microtia

For many, the term "microtia" is an unfamiliar one. To the parent whose child is born with this rare disorder, the little word can be quite disconcerting. Microtia, literally meaning "little ear," is a congenital disorder that results in an under- or malformed ear and is associated with conductive hearing loss of varying severity.

What is microtia?

Simply put, microtia is a congenital deformity that results in a small, poorly formed external ear. If the external ear is entirely absent, then this is known as anotia. The malformation of the external ear can vary wildly; in some cases the ear lobe or hollow of the ear may partially form, with the rest of the ear missing. In other cases there may only be a small portion of ear tissue where it would normally grow. In the most extreme cases, called anotia, the external ear doesn't to grow at all. Microtia can present unilaterally (on one side only), or bilaterally affecting both ears). For reasons that we don't fully understand yet, microtia is usually unilateral, affecting the right ear more often than the left. Occurring only in about 0.76 to 2.35 per 10,000 births, this condition is exceptionally rare.

All children born with microtia share the most common complication associated with the malformation: reduced hearing. One of the defining characteristics of the disorder is aural atresia or aural stenosis. Aural atresia means that no external ear canal or drum has formed, while aural stenosis refers to a narrowing of the ear canal and a small ear drum. Either of these structural problems make it extremely difficult for sound to travel to the inner ear, resulting in a least some hearing loss.

In the vast majority of cases microtia is diagnosed by itself without any other abnormalities. However, in rare cases microtia can occur simultaneously with other malformations as part of a syndrome. These include:

• Hemifacial microsomia, which causes half of the face to grow out of proportion to the other half.
• Treacher Collins Syndrome, which affects both ears and the eyes.
• Goldenhar Syndrome, which affects the growth and development of the ears, nose, soft palate, lips, and jaw.

What causes microtia?

Though medical science is diligently studying the condition, we still aren't sure what causes microtia. It is important for parents of children born with microtia to understand that it isn't their fault. Despite the fact that we're not sure how it happens, after years of research and study there is absolutely no evidence to suggest anything the mother does during pregnancy causes it. Even in cases where one or both parents were born with it themselves, it is not necessarily inherited by their children.

As researchers have worked tirelessly towards understanding microtia's causes, they have in turn discovered a great deal about the condition. The best way a parent can help their children is to learn more about microtia, how it effects hearing, and the available treatment options.

It is known that while in the womb, ears are formed in the area of the neck before they move upward to the head. When the supply of blood to the area is interrupted at any point, the ears may not form properly and microtia or anotia results.

What are the grades of microtia?

Microtia presents in one of four grades:

• Grade I is defined by a small ear with mostly normal development, however there may be a narrow or missing ear canal.
• Grade II is characterized by some abnormal external ear development, usually in the top two thirds of the ear. Children with grade II usually have a narrow or missing ear canal.
• Grade III microtia is the most common. Children with grade III have small, underdeveloped ears that somewhat resemble a peanut, and have no external ear canal or drum.
• Grade IV describes a complete absence of the ear and its external structures (anotia).

What are the treatments for microtia and anotia?

Partially because of its rarity, microtia is almost never caught on prenatal ultrasounds. This, coupled with the varying ways it can present, has led to a few different treatment options.

The most basic treatment option is no treatment at all. If the deformity isn't severe, and isn't interfering with your child's social development, you may choose to forego treatment altogether. This course of action should be examined carefully, and only truly considered if your child is coping with their microtia well. Negative social interactions, like bullying, might play a role in this decision.

Another possible form of treatment is a prosthesis. Synthetic materials are always improving in quality and can offer some fairly convincing skin tones. That being said, even the best prosthesis can be spotted, and they usually have an unnatural feel to them. Additionally, prosthetics often require surgical pins for proper placement, and once you've chosen to go this route, you can't opt for surgical ear reconstruction later.

The final treatment option is surgical ear reconstruction. For this treatment there are two prevailing techniques:

• The natural cartilage technique utilizes your child's own skin and cartilage from their rib to create a framework for a new ear. This treatment is invasive and requires between two and five surgeries before it is compete. The advantage to this technique is that the new ear is formed entirely from your child's own body tissue. However, the most notable disadvantage is that it requires you to wait until your child is between seven and ten years old to ensure there is enough rib cartilage to create an adult sized ear. This method has been in use for over 50 years, and is considered the “gold standard” in ear reconstruction.
• Medpor reconstruction uses a polyethylene plastic implant as a framework for the patient's own tissue to grow around and into. This method requires only one or two surgeries and can be performed on children as young as three years old, but the use of a plastic implant is undesirable to many parents.
• Depending on the anatomy of the ear canal, the hearing loss associated with microtia may also be treated. Ear canal surgery is the most common practice, but a bone anchored hearing aid (or BAHA) or a cochlear implant are options for children and adults who cannot undergo surgery.

Please note that I do not perform surgery on children under 7 years old. The minimum age is 7 years old.

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