The term microtia comes from two Latin words ‘micro’ and ‘otia’ which means ‘little ear.’ It is a rare congenital abnormality that affects about 1 to 5 babies in 10,000 live births every year. Bilateral microtia is even more uncommon and estimated to affect on 1 in 25,000 live births a year. Read on this post, to know more about microtia causes and treatment.
What Is Microtia?
Microtia is a congenital deformity that affects the outer ear of the growing foetus in the womb. Microtia can be detected in the early phase of pregnancy during the first trimester. Congenital microtia is a condition wherein one or both the ears of the baby does not fully develop, it may vary in severity and appearance, and usually appears smaller in size close to the shape of a peanut. In the U.S. microtia ears is very rare and happens in about 1 in 5000 live births and in 90% cases only affects one ear and is more common in male babies. Microtia ear is often associated with the absence of the ear canal, also termed as canal atresia or the presence of an extremely narrow ear canal also termed as canal stenosis.
What Are the Four Grades of Microtia?
The severity of microtia can be divided into four categories:
1. Grade 1
In grade 1 microtia the ear appears a little smaller than normal but mostly all the important features of the ear are present. The ear canal may be narrow or missing and other parts may or may not have slight alterations in shape, form or size.
2. Grade 2
Grade 2 microtia is also known as ‘conchal type microtia,’ usually in this case lower two-thirds of the ear is developed normally but remaining one-third of the ear is missing or not formed properly. The ear canal is either absent or extremely narrow.
3. Grade 3
Grade 3 microtia can be defined as the most common type of microtia and is often termed as ‘lobular type microtia.’ In this case, the only feature that remains is a tiny peanut shaped ear lobe and mostly the ear canal is completely absent.
4. Grade 4
Grade 4 is the most severe form of microtia which is extremely rare and is termed as ‘anotia.’ In this case, a complete absence of the external ear along with the ear canal is observed either unilaterally or bilaterally.
Major Causes of Microtia
Microtia is generally developed in the early stages of pregnancy in the first trimester and in most cases the exact cause is unknown. However, some of the possible causes of microtia can be:
1. Drug and alcohol consumption during pregnancy
Excessive intake of drugs and alcohol during pregnancy can be a cause for microtia in the developing baby. Microtia can be caused due to Fetal Alcohol Syndrome in developing foetus. Another cause can be due to the usage of a medication ‘Accutane or isotretinoin’ during pregnancy for the treatment of acne. This medicine is associated with a number of congenital abnormalities including microtia in babies. A diet that is low in folic acid and carbohydrates can also trigger microtia in babies.
2. Inadequate blood supply to the foetus
Sometimes the foetus is positioned in such a way that there is a blockage in the blood supply due to the pressure from inside of the womb or umbilical cord during the first trimester. This may cause microtia or hinder the complete development of the external ear of the baby.
Another major reason that may cause microtia in babies is if the mother is diabetic prior to pregnancy. Diabetic mothers are more likely to give birth to babies with congenital abnormalities like microtia as compared to other non-diabetic pregnant women.
Can Microtia Be Genetically Inherited?
While there is no proper study backing the actual cause or genetic inheritance of microtia, in the majority of cases, microtia is a randomly occurring anomaly in the early development of the embryo. In most cases, babies born with microtia have no family history of microtia or other ear-related problems in both the maternal and paternal side of their families. Even in cases of twins, one child may be born with microtia while the other twin will be completely healthy without any signs of microtia. In about 5% of cases, it is observed that microtia can be present in multiple family members. It may occur that one family member is affected with right ear while the other member is affected with the left ear. It can be said that if a couple has one child born with microtia then there is an estimated increased 5% risk of having another child with microtia. Similarly, if one of the parents is affected with microtia then again there is an estimated increased risk of 5% of having a child affected with microtia.
Risks Associated With Microtia
There are certain risks associated with microtia such as:
1. Infection in the ear
It’s very common for babies born with microtia to have ear infections throughout their lives.
2. Hearing loss
Apart from the visual deformity due to underdeveloped growth of the ears, children born with microtia may also suffer from hearing loss due to complete closure or absence of external ear canal. The hearing loss may also affect the speech of the child.
3. Mental anxiety and a feeling of self-consciousness
In some cases, children may not suffer complete hearing loss, but even then they start feeling the difference when they reach about 6-7 years of age. Many children get teased in school for not appearing normal like other kids which may affect the overall confidence of the child. They may start feeling inadequate and self-conscious due to their visual deformity.
Apart from the above, most children born with microtia do not have any other significant medical problems.
Diagnosis of Microtia
Microtia is a congenital abnormality and can be visible immediately at birth by your child’s paediatrician through physical examination. In order to determine the grade and severity of the condition, the doctor may recommend a screening test with ENT specialist and paediatric audiologist. The doctor may recommend a CAT scan to diagnose the extent of microtia when the child comes of age. An ENT specialist confirms the presence or absence of the ear canal and a further examination with an audiologist will determine the extent of hearing loss if any. Since microtia is a congenital anomaly that can occur with other genetic disorders, the doctor may recommend further tests to rule out other diagnoses. He may recommend an ultrasound to check the functioning of the kidney, liver and other organs. In case the child shows symptoms of other genetic disorders, the doctor may refer to a genetic specialist for further investigation. Craniofacial microsomia is one of the most common microtia associated syndromes which may happen along with microtia, in such cases, the paediatrician may refer to a craniofacial specialist for further investigation, treatment and therapy sessions.
Treatments for Microtia
Depending upon the extent and severity of the condition, your doctor may recommend a microtia ear reconstruction surgery of the ear canal. However, if you are sceptical about the surgery, then you must speak with your doctor and wait till your child gets older. In most cases, doctors themselves advise waiting till the child gets older for the surgery as more cartilage is available to graft as the child gets older. The surgical treatments for microtia include the following:
1. Rib cartilage surgery
This treatment requires about two to four surgical procedures over a period of a few months to a year. Rib cartilage graft surgery is performed by removing the rib cartilage from your child’s chest and using it to create the shape of an ear. The next procedure is to implant this under the skin where actually the ear should have been. Once the new cartilage has been implanted additional surgeries may be performed to correct the position of the ear. This surgery is recommended for children between 8 to 10 years of age. The child’s rib cartilage is chosen for this surgery as it is very strong and since the tissue is from the child’s own body the chances of rejection of the implant material is very less. Some of the side effects of the surgery include pain and scarring at the site of surgery and the rib cartilage tends to feel firmer and stiffer as compared to the ear cartilage which may cause discomfort.
2. Medpor graft surgery
Medpor surgery is different as compared to the rib cartilage surgery as it involves using a synthetic material for implantation as compared to the rib cartilage. This type of surgery mostly involves only one surgical procedure and the implant material is covered using the scalp tissues. This surgery is safe to be performed on children above 3 years of age. The best part about this surgery is that the results are more consistent as compared to rib cartilage surgeries. The side effects of the procedure are that the life of medpor implants is still unknown so some doctors may not perform this procedure. Another downside of the treatment is that there is an increased risk of infection and loss of implant as it is not incorporated into the surrounding tissue.
Non-Surgical Treatments for Microtia
There are non-surgical alternatives which can be effective in the treatment of microtia. Sometimes, when the condition is not severe, parents also opt for no-treatment after consultation with the doctor. Some of the minimally invasive non-surgical procedure for microtia include:
1. A prosthetic ear for microtia
Prosthetics are quite effective and look like a real ear which can be worn by the children with the help of medical adhesive or minimally invasive surgically implanted anchor system. The procedure is quick and involves minimal recovery time. The prosthetic external ear is a great option for kids who can’t go for reconstructive surgeries or if the surgeries were not successful. The downside of the treatment includes the risk of skin infections due to sensitivity to medical-adhesives, and high maintenance.
2. Synthetic ear implants
Instead of using rib cartilage, in this treatment, an artificial ear is made using synthetic material which can be affixed to the spot with adhesive or surgical procedure. The advantages of this treatment include early treatment which can be done at the age of three and no chest scar since rib cartilage is not used. However, disadvantages include a higher risk of complications and potential long-term issues as compared to autologous construction.
When to See a Doctor?
If you see that your child has microtia symptoms then early diagnosis and consultation with your doctor will be very helpful. If your kid has a hearing difficulty then your paediatrician will refer to an audiologist and an ENT specialist and the lien of treatment will be:
- Regular hearing tests will be conducted to monitor the extent of hearing loss.
- Recommend the usage of hearing aids.
- May recommend surgery for the recreating the ear canal and improve hearing.
- May recommend additional assessments for your child as needed.
Most children born with microtia may experience complete or partial hearing loss in the affected ear. This may also affect their speech as they are unable to hear the pronunciation and sentence formations correctly. It may have a negative impact on their quality of life if not treated correctly. In most cases, corrective surgeries are recommended and generally, children adapt well to the recovery. Certain lifestyle changes and adjustments along with proper therapy sessions will be beneficial.
Children born with microtia can lead a completely happy, healthy and stress-free life with proper treatment and lifestyle modifications. Speak to your doctor openly about the situation to decide the best course of action that suitable for your child.