Background
Hearing loss associated with CFM has been well described in individuals with microtia and EAC atresia. Patients with microtia and malformed ears are typically diagnosed at birth and should undergo audiological testing. Hearing loss in these patients is typically conductive in nature due to external ear abnormalities, aural atresia and Eustachian tube dysfunction. Sensorineural hearing loss is less common but may also be present in individuals with CFM due to inner ear anomalies seen in these patients.
Hearing consideration
Microtia is accompanied by congenital absence or stenosis of the external auditory canal with variable middle ear anomalies this causes a significant conductive hearing loss. Children with unilateral microtia seem to develop normally. Parents usually do not notice a significant difference between their young children and their siblings without microtia. This is the reason why unilateral hearing loss has been undertreated by many otolaryngologists and usually ignored by plastic surgeons treating microtia.
However, when children with microtia are older, and communication becomes more sophisticated, hearing issues become more obvious. Sound localization and hearing comprehension especially in noisy environments become more difficult.
Patients with microtia tend to turn their unaffected ear in the direction of sound, because the head itself casts a sound shadow, which reduces comprehension in the unturned normal ear.
Once a child is 2.5 years of age, a computer tomography (CT) scan of the temporal bones can allow an otologist to determine if an atresia patient is a possible candidate for a canalplasty. The otologist needs to view the actual scan rather than the radiologist’s report. The Jahrsdorfer 10-point grading scale is commonly used to predict surgical candidacy depending on key features seen on the CT scan.
The treatment of hearing loss by an otologist should be coordinated with the surgeon responsible for the outer ear surgery. Traditionally, atresia repair is done after the costal cartilage ear reconstruction, since almost all otologists perform the ear canal reconstructions through a posterior mastoid skin incision to access the temporal bone. That approach compromises the blood supply of the mastoid skin that is used to cover the cartilage framework. However, prior atresia repair does not jeopardize the success of ear reconstruction using an implant covered by a vascularized fascia flap. With an alloplastic reconstruction, atresia repair is best done before or at the same time as the ear reconstruction as the canal helps with positioning of the reconstructed ear. Also, early atresia repair potentially improves hearing at a critical period of early brain development.
If the patient is not a candidate for atresia repair and a functional canal, a faux-canal can be created at the time of microtia reconstruction.
To speak to a microtia expert and explore various state-of-the-art treatments, contact Dr. Tahiri today.
Atresia Repair
One option for improving hearing is surgical correction of the anatomical malformation. Atresiaplasty was first described by Thomson in 1843. His technique has been modified and improved over the past 175 years.
The degree of hearing improvement obtained with atresiaplasty is associated with higher Jahrsdorfer scores. Patients with craniofacial syndromes, such as Treacher-Collins or craniofacial microsomia, are often poor surgical candidates due to poorly developed middle ear structures reflected in lower Jahrsdorfer scores. Selection of appropriate surgical candidates for atresiaplasty and meticulous surgical technique is essential to achieving optimal patient outcomes.
For patients who are favorable candidates for atresiaplasty based on hearing and radiographic assessments, the goals of atresiaplasty, expected outcomes and anticipated postoperative care should be discussed. The main goals of atresiaplasty are to create a skin lined ear canal and a mobile tympanic membrane that is coupled to a mobile ossicular chain. Hearing may improve in cases of favorable anatomy. Post-operatively, patients with a patent ear canal and a well-defined postauricular sulcus can potentially be fit with ear level amplification. Patients who undergo atresiaplasty will typically require ongoing otologic management to clean the ear canal.
Patients and parents need to consider their options for hearing management in the context of their preferences for microtia management.
One advantage of the Medpor or Omnipore ear reconstruction is that Atresia reconstruction can be performed before the ear reconstruction or at the same time as the ear reconstruction. When an atresiaplasty is performed at the same time of the ear reconstruction, it is called a Combined Atresia Microtia (CAM reconstruction) and our team has the most experience in the world.
Bone Anchored Hearing Aid
BAHA stands for Bone Anchoring Hearing Aid. It is a surgically implantable system for treatment of hearing loss.
It has three parts:
- A sound processor
- An external abutment- Transmits sound vibrations
- A titanium implant- Sets up vibrations within the skull and inner ear
A Baha implant enhances natural bone transmission as a pathway for sound to travel to the inner ear, bypassing the external auditory canal and middle ear.
If the patient is not a candidate for an Atresia repair, a BAHA can easily be placed at the time of microtia reconstruction. A BAHA is placed using the same incision we use for the ear reconstruction; thus, no new incisions are made. Moreover, we use the latest form of BAHA, it is a BAHA 5, which works with a magnet and has no external screw coming out the scalp.
The advantages having a BAHA placed at the same time as the reconstruction include:
- No new incisions are made
- The patient does not have to go through anesthesia twice
- We have a lot of experience with placing BAHAs
- Since the surgical site is already exposed, the BAHA placement is fast and is done very safely
- No screw comes out of the scalp with the new magnetic BAHA 5
Dr. Tahiri specializes in microtia surgery for children. Patients from all over the USA and beyond visit his Beverly Hills office to discuss microtia and surgical treatment.