- My child was born with microtia/atresia in both ears. What now?
- Why aren’t all children candidates for atresia surgery?
- At what age should I pursue the CT scan?
- At what age should I pursue hearing testing?
- What is the difference between atresia and stenosis?
- What is the difference between conductive hearing loss and nerve-type hearing loss?
- What are the problems children have with unilateral atresia? Should I have my child undergo the operation to open the ear canal?
- What is involved in the atresia operation?
- What can we expect after surgery?
- Does the method of microtia repair matter with regard to atresia repair?
- At what age do you recommend atresia surgery?
- Can atresia surgery be performed in adults?
- What are the potential risks for atresia surgery?
- Will the hearing results be lifelong?
- What if atresia surgery fails to improve the hearing?
My child was born with microtia/atresia in both ears. What now?
For children born with bilateral microtia and atresia, the first step is a hearing test. Because we cannot put a newborn in a sound booth and ask if he/she can hear the tones or the words, we have to do a special test called a Brainstem Auditory Evoked Response test, often called a “BAER” or “ABR” or Auditory Brainstem Response test.
Much like an EEG, this test measures the coordinated electrical activity (response) in the auditory nerve and brainstem relay centers when the ear is presented with a sound (usually a click or a tone). The most important part of this test is to measure the bone conduction thresholds. This means that the audiologist or tester places a microphone on the bone of the skull and delivers the signal through the bone to the inner ear. This test measures how well the inner ear receives the sound signal and converts it to an electrical signal. In most cases of atresia, the inner ear has developed normally and can convert sound to electrical energy that we can measure with the BAER test.
If the bone conduction BAER test shows normal responses for the inner ear (most times the examiner is not able to isolate and test each ear individually), a bone conduction hearing aid (e.g., Baha softband) is placed on the child’s head to take advantage of the normal function of the inner ear. The child wears this bone conductor until he/she is ready for atresia surgery, or, if the child is not a candidate for atresia surgery, placement of a more permanent bone anchored hearing aid (BAHA).
If the BAER test shows no response in either ear to bone conduction stimulation, the child has a nerve-type hearing loss (sensorineural hearing loss), and the BAHA will be of no benefit. At that point, the child may be a candidate for a cochlear implant. Talking to your audiologist and otologist is the best way to sort these issues out.
Again, most children with atresia have normal inner ear development, so (fortunately) sensorineural hearing loss is rare in these cases.
One other issue – a child with unilateral or bilateral atresia should have a thorough history and physical examination by the pediatrician to rule out other abnormalities. Many pediatricians recommend an ultrasound test of the kidneys since the ear and the kidneys develop about the same time and share many of the same proteins. Atresia can also accompany syndromes that must be diagnosed, including Treacher Collins syndrome, Goldenhar/hemifacial microsomia, etc.
Why aren’t all children candidates for atresia surgery?
A child must have some development of the middle ear structures – an air-containing space, the ear bone (hammer, anvil, and stirrup), and an open (oval) window into the inner ear. If the child has no space in the middle ear, the ear bones cannot vibrate and sound conduction will not be restored. If the oval window is closed, we have found only about 50% of children who have a drillout of the oval window will enjoy good hearing long-term. If the all-important facial nerve is in the way, surgery to open the ear canal would be too risky, and the child might suffer paralysis of that side of his/her face. Finally, the bone separating the brain from the ear may hang down too low and also be in the way for any attempt to open the ear canal. We would not want to risk brain injury in attempting to open the ear canal!
The only way to determine if a child is a candidate anatomically for atresia surgery is by a special CT scan. Many parents ask for the specifications of the CT scan: Thin section (1 mm cuts) high resolution axial and coronal CT scan of the temporal bone. The anatomy of the middle ear on the CT scan is graded on a 10 point scale first proposed by my mentor, Dr. Jahrsdoerfer. Generally speaking, a 7.5 and above correlates with an 80-90% chance of achieving normal or near-normal hearing with surgery.
A recent audiogram is also critical to ensure that the inner ear is working properly. The audiogram must have bone conduction thresholds of the atretic ear in order to test the inner ear’s function.
At what age should I pursue the CT scan?
Generally speaking, we do not recommend a CT scan until the age of 5-6, when the patient and family are beginning to consider the atresia surgery. See At what age do you recommend atresia surgery?.
At what age should I pursue hearing testing?
Hearing testing (BAER) should be done after birth and at least yearly thereafter. As the child gets older, soundfield (in a sound-proof booth) testing will be better than BAER testing. And as the child gets older still, visual reinforced audiometry or testing of individual ears with air and bone conduction thresholds will be possible.
For unilateral atresia, I recommend hearing testing yearly to ensure that the “normal” ear is working well.
What is the difference between atresia and stenosis?
Atresia means complete lack of development of the ear canal, eardrum, and various levels of development of the middle ear space and ear bones. Stenosis means narrowing – a canal is present but it is very narrow, sometimes as narrow as 1 mm. Stenosis may be accompanied by a normal middle ear (in which case the child may have normal hearing) or may be accompanied by an underdeveloped middle ear (in which case the child may have a significant conductive hearing loss).
What is the difference between conductive hearing loss and nerve-type hearing loss?
Conductive hearing loss is caused by a failure of the outer and middle ear to conduct sound energy to the inner ear. All patients with atresia have a conductive hearing loss. Other causes of conductive hearing loss include a wax impaction, a hole in the eardrum, fluid in the middle ear space, or simply putting your finger in your ear!
Nerve-type hearing loss (sensorineural hearing loss, SNHL) is caused by a problem in the inner ear, the cochlea. Unfortunately, at this time, there is no medicine and no surgery to improve SNHL. We generally recommend hearing aids for this type of hearing loss (if the loss is profound, the patient may be a candidate for a cochlear implant).
Because the middle ear develops from different structures and at different times from the inner ear, fortunately, most children with atresia have normal inner ear function (no SNHL).
What are the problems children have with unilateral atresia? Should I have my child undergo the operation to open the ear canal?
Patients with unilateral hearing loss have two primary problems – difficulty hearing in background noise and inability to locate sound in space. You may have called to your child and your child has no idea where you are – they cannot locate a sound source.
Successful surgery to open the ear canal and restore hearing to the ear will greatly improve your child’s ability to locate sound in space and to hear better in background noise – parties, restaurants, noisy classrooms, in the car with the windows down, etc.
Only you, your child, and your family can make the decision to have surgery, if your child is a candidate for the operation.
What is involved in the atresia operation?
The operation involves 6 basic steps: 1) opening an ear canal by removing (drilling) bone from the surface of the skull into the middle ear space, 2) identifying and freeing the bones of hearing, 3) constructing an eardrum from tissue that covers the chewing muscle just above the ear (temporalis fascia), 4) harvesting a skin graft from the upper arm and using the skin graft to line the new eardrum and new canal, 5) making an opening (meatus) in the reconstructed auricle (usually rib cartilage) from the microtia repair, and 6) delivering the skin graft through the opening to align the newly-created bony ear canal with the opening (meatus) in the previously reconstructed auricle and sewing the skin graft to the native skin at the auricle.
What can we expect after surgery?
Please see “Instructions for the Care of Your Ear After Atresia Surgery.”
The hearing will improve after the packing is removed from the ear one week after surgery. 4-5 weeks after surgery, we need to clean the ear of the dead skin from the skin graft. It is at this time that we get the first postoperative hearing test.
Depending on the anatomy of the middle ear and the surgery, your child can experience some improvement in hearing to substantial improvement – even normal hearing in many cases!
Does the method of microtia repair matter with regard to atresia repair?
Most definitely. Currently, there are two preferred methods to reconstruct the auricle – Medpor, a porous polyethylene implant, and the patient’s own rib cartilage that is sculpted to the form of an auricle. There are proponents and detractors of both methods.
For the purposes of atresia repair, we generally recommend Medpor microtia repair AFTER the atresia operation because if the Medpor implant is placed first, and the implant becomes exposed during the atresia surgery, because the implant does not have its own blood supply, it will stay exposed and may become infected or may extrude (come out). For these reasons, we recommend atresia surgery BEFORE Medpor.
With (autologous – patient’s own) rib cartilage, the cartilage IS the patient’s. It recruits its own blood supply and is extremely durable. We can open it carve it, expose it, and do what we need to do to make a nice meatus, and a meatus that aligns properly with the bony canal. For these reasons, we recommend atresia surgery AFTER rib cartilage repair of microtia.
One other important point – about 15-20% of children who have atresia surgery will need a revision operation. Reasons for revision atresia surgery include narrowing (stenosis) of the opening, new bone growth in the canal, chronic moisture/infection, or loss of initially excellent hearing. We worry that if a child undergoes revision atresia surgery with the Medpor implant that the implant will again be at risk for exposure, extrusion, and infection during the revision atresia surgery. For these reasons, we tend to favor rib graft microtia repair for patients who are candidates and wish to pursue atresia surgery.
For additional details, please see http://www.microtia-atresia.com.
At what age do you recommend atresia surgery?
This question remains hotly debated. While some surgeons offer atresia surgery at age 3-4, we feel that performing the atresia operation this early does not benefit these children. Children have a remarkable ability to heal. This ability to heal actually is counterproductive when we want the new canal to stay open. The tendency is for the new canal to close, to fill in, because the younger child heals so well. Sometimes we have to open the mastoid cavity (mastoidectomy) in children with a different type of ear problem (cholesteatoma – a skin cyst that can grow in the ear). When we go back in the ear 9-12 months later to make sure the cholesteatoma has not regrown, the mastoid cavity has often completely filled in with new bone. The aggressive healing powers of young children would tend to close off the newly created ear canal.
The age of the child is also important when discussing postoperative care. The child has to be mature enough to sit still in the office 1 week after surgery for me to remove the delicate packing in the new ear canal. In addition, the child must sit still and allow me to clean the ear canal of the dead skin one month after surgery. If the child cannot sit still, I have to take him/her back to the operating room for another anesthesia for the cleaning or the removal of packing. If the child cannot sit still, he/she could jeopardize an otherwise successful operation.
Interestingly, one Korean atresia specialist has a large population of children with atresia; he does not recommend atresia surgery until the child is 12! It is certainly possible, as he argues, that after the age of 12, the risk of new bone formation in the new canal is much lower.
Nevertheless, we recommend atresia surgery at the age of 6-7, after the rib graft microtia repair, when the child is getting ready to go into first grade.
Can atresia surgery be performed in adults?
Absolutely, but the same candidacy criteria that apply for children also apply to adults. The adult must have normal inner ear function in the involved ear (as demonstrate on the hearing test), and the CT scan must show favorable anatomy of the middle ear (graded on the Jahrsdoerfer scale – see above) and facial nerve for me to recommend atresia surgery.
What are the potential risks of atresia surgery?
The risks of atresia surgery include but are not limited to infection, hearing loss, failure to improve the hearing, eardrum perforation, dizziness, change in taste, facial nerve weakness (1/1000 in our hands), and stenosis/narrowing of the ear canal which would require a revision operation.
Percentages of each potential complication are on a case by case basis, based on the anatomy of the CT scan, but about 15-20% of cases will require a revision procedure to reopen the canal or remove scar tissue that has caused the ear bones to vibrate poorly. Eardrum perforation is rare, and facial nerve injury is rarer.
Will the hearing results be lifelong?
Yes, that is our goal.
What if atresia surgery fails to improve the hearing?
If the hearing does not come up after atresia surgery, there are a couple options: do nothing if the child has unilateral atresia, revision surgery to improve the hearing, the BAHA system, or a conventional hearing aid that can easily be worn in the new canal.