Aural atresia is a condition where the ear canal is either completely absent or abnormally narrow, preventing sound from reaching the middle ear through the normal pathway. It affects roughly 1 in 10,000 to 20,000 births and is almost always present from birth, though in rare cases it can be acquired later in life. The condition ranges from mild narrowing (called stenosis) to a fully closed or missing canal, and it can affect one ear or both.
How Aural Atresia Affects Hearing
Sound normally travels through the ear canal, vibrates the eardrum, and passes through three tiny bones in the middle ear before reaching the inner ear. When the canal is absent or blocked, that entire chain is disrupted. About 90% of people with aural atresia have what’s called conductive hearing loss, meaning the inner ear works fine but sound simply can’t get to it. The hearing loss is typically significant, in the range of 60 to 70 decibels. For context, that’s roughly equivalent to plugging your ear with your finger and then adding earmuffs on top.
When only one ear is affected (unilateral atresia), a child can still hear through the other ear. This makes it easier to develop speech and language, though localizing sounds and hearing in noisy environments remains difficult. When both ears are affected (bilateral atresia), early intervention with hearing devices is critical to support language development during the first years of life.
The Connection to Microtia
Aural atresia rarely occurs in isolation. Because the outer ear and the ear canal develop from the same structures during fetal growth, a malformed canal usually comes alongside a malformed outer ear, a condition called microtia. The severity of the outer ear deformity tends to correlate with how affected the middle ear structures are on the inside.
Microtia is classified on a scale from Grade I to Grade IV. In Grade I, the ear is slightly smaller than normal but all its parts are present. Grade II involves a noticeably underdeveloped ear, particularly in the upper half. Grade III, the most common form, leaves only a small nub of cartilage and a rotated earlobe (sometimes called a “peanut ear”). Grade IV is the complete absence of the outer ear. Aural atresia is most commonly associated with Grade III and Grade IV microtia.
Some children with aural atresia also have broader conditions such as hemifacial microsomia, where one side of the face is underdeveloped. Preauricular pits (tiny holes in front of the ear) and small skin tags near the ear can also be present.
How It’s Diagnosed
Aural atresia is often visually obvious at birth, especially when it accompanies microtia. However, understanding what’s happening inside the ear requires imaging and hearing tests. Newborns with bilateral atresia typically receive a brainstem hearing test (a painless, non-invasive screen) within the first few months of life to confirm the degree of hearing loss and verify that the inner ear is functioning.
A high-resolution CT scan of the temporal bone is the key tool for mapping the anatomy. It reveals which middle ear structures are present, whether the tiny bones are formed correctly, and where the facial nerve runs (an important safety consideration for any future surgery). CT scans are generally delayed until at least age 2, partly because the structures are still growing and partly because the scan provides the most useful information when surgical planning becomes relevant.
The Jahrsdoerfer Scale
Surgeons use a 10-point scoring system called the Jahrsdoerfer scale to evaluate CT scans and determine whether surgical reconstruction is a good option. Points are awarded based on what structures are present and functional: 2 points for a normal stapes bone (the innermost of the three hearing bones), and 1 point each for the other two hearing bones, the connection between them, open oval and round windows (the passageways into the inner ear), an air-filled middle ear space, an air-filled mastoid bone, a normally positioned facial nerve, and a normal outer ear. A score of 7 or higher suggests a good candidate for surgery. Scores below 6 are associated with poor surgical outcomes.
Hearing Solutions for Young Children
Because the ear canal is absent, traditional hearing aids that sit in the ear aren’t an option. Instead, the goal is to bypass the canal entirely and send sound vibrations directly through the skull bone to the inner ear.
For infants and toddlers, the most common starting point is a bone conduction hearing device worn on a soft headband. This can be fitted as early as a few months of age and delivers sound through gentle vibration against the skull. Studies of children with bilateral atresia show meaningful hearing improvement with these headband devices, making them a valuable bridge during the years before a child is old enough for more permanent options.
Once a child reaches age 5 or older, surgically implanted bone conduction devices become an option. These devices anchor to the skull bone and transmit sound vibrations more efficiently than the headband version. Several types exist, including models that sit partially under the skin and others that connect through a small post. They are particularly useful for children who aren’t strong candidates for canal reconstruction, or as a reliable backup if reconstruction doesn’t achieve adequate hearing.
Surgical Canal Reconstruction
The most ambitious treatment is atresiaplasty, a surgery that creates a new ear canal and connects it to the middle ear structures. When it works well, it can restore hearing through the natural air conduction pathway. In one long-term study, surgery improved hearing by an average of 30.5 decibels initially, with two-thirds of patients achieving hearing levels of 30 decibels or better in the first year. That’s close to the range of normal conversational hearing.
The catch is that results don’t always hold. Over an average follow-up of about four and a half years, hearing declined by roughly 8 decibels from its best post-surgical level, leaving a final average improvement of about 22 decibels. Sixty-four percent of patients maintained stable hearing over time (defined as losing no more than 10 decibels from their best result), but 36% experienced more significant decline. Most of the change happened within the first three years after surgery, with results generally stabilizing after that.
One of the biggest challenges with atresiaplasty is restenosis, where the newly created canal narrows or closes again due to scarring. Even at the most experienced surgical centers, up to half of patients require revision surgery because of restenosis, recurrent infections in the new canal, or hearing that didn’t improve enough. The surgery also creates scar tissue that can complicate future outer ear reconstruction if a child plans to have cosmetic surgery for microtia. Timing and sequencing of these two procedures requires careful coordination.
Choosing Between Surgery and Devices
The decision between canal reconstruction and implantable hearing devices depends on anatomy, age, and family priorities. Candidates with a Jahrsdoerfer score of 7 or above have the best shot at a successful atresiaplasty. For those with lower scores, implantable bone conduction devices tend to produce more reliable and stable hearing outcomes with fewer complications.
Implantable devices also avoid the risk of damaging middle ear structures or complicating future cosmetic ear surgery. On the other hand, a successful atresiaplasty restores hearing through the body’s natural pathway without requiring an external device. For children with bilateral atresia, some families pursue reconstruction on one side and an implantable device on the other, hedging their options.
Regardless of the path chosen, the inner ear in aural atresia is typically healthy. Bone conduction hearing thresholds remain stable over time, which means the potential for good hearing through bone conduction devices or successful surgery is preserved even if treatment decisions are delayed.