Canalplasty Technique

* This information was gathered by directly speaking with surgeons, families and individuals who have already had surgery, and through personal research. The remaining information has come from noted sources.

What is Atresia?

Right ear showing Microtia and Atresia (absence of an ear canal)

Atresia, (also known as aural atresia) is the absence or closure of the external auditory ear canal. The middle ear bones (incus, stapes, and malleus) may be malformed including the narrowing of the ear canal, known as canal stenosis. Atresia is Latin for absence of an opening. An Atretic ear is often sealed off by the skull with no opening (canal) being present. Atresia is a congenital birth defect. There are varying degrees of middle ear bone abnormalities such as: a.) the incus, stapes and malleus all may be present but are not functioning for one reason or another b.) one or more of these three bones may be missing, not connected to the oval window and or are not present in the middle ear structure at all c.) all three of these bones may be present however are misshaped or malformed. A majority of the time, the Cochlea still functions and the auditory nerve is intact. There usually will be a hearing loss to some degree mainly because of having no ear canal allowing sound to travel through to the inner ear. If your child has unilateral Atresia in most cases the non-Atretic ear may have normal hearing. However, sometimes the non-Atretic ear may be affected with a hearing loss as well.

Is surgery available that can help repair Atresia?

Yes.  This surgery is known as Canalplasty or Atresia Repair.  However, an individual with Atresia must be a candidate for canalplasty.  Not every individual can meet the required criteria needed to qualify for canalplasty.

What is Canalplasty (Atresia Repair)?

Canalplasty is a surgical procedure where an ear canal can be reconstructed.  This reconstruction is performed by creating an opening in the skull (where an ear canal would be present) and lining the newly created opening with a skin graft.  In addition to creating the ear canal itself, a surgeon may be able to to manipulate the middle ear bones helping to restore hearing within a normal hearing range (20dB) or better.  The following description of Canalplasty is described by Dr. Brad Kesser:  Surgical repair of congenital aural atresia attempts to restore natural hearing to the ear by opening an ear canal, freeing the ear bones (“ossicles”), constructing a tympanic membrane (eardrum), lining the new bony ear canal with a very thin skin graft, and creating an opening (“meatus”) in the reconstructed auricle that is aligned with the new bony ear canal.  The finished result is a healthy skin-lined ear canal with tympanic membrane and ossicles that vibrate freely allowing sound energy to be conducted efficiently to the inner ear.  In selected patients, the chances of achieving normal or near normal hearing with surgery approach 90-95% (cited by Dr. Brad Kesser, University of Virginia School of Medicine, http://www.medicine.virginia.edu/clinical/departments/otolaryngology/atresia/Atresia-page).

What determines if you are a candidate for Canalplasty?

There are a handful of factors that help determine if an individual with Atresia can be a candidate for Canalplasty.

1.  Functioning cochlea:  An audiogram can help determine if an individual has what is called a “normal inner ear.”  An individual’s cochlea must function in order to be considered a candidate for canalplasty.

2.  Development of the middle ear space, facial nerve, and inner ear structures:  A CT or CAT Scan must be taken of the ear in order for an ENT (ear, nose and throat specialist or otolaryngologist) to be able to view all of the structures inside of the ear.  The middle ear space and inner ear structures must be intact within reasonably good standing and the facial nerve can not be in the way of where surgery would be performed.  A 10 point grading scale is then used to determine candidacy when looking for these structures.  This 10 point scale is called the Jahrsdoerfer or “J” scale, developed by Dr. Robert Jahrsdoerfer, and is used to grade the individual’s ear anatomy.  The “J” scale is broken down on the following point system:

Scoring for the Jahrsdoerfer Grading System:
Stapes bone 2
Oval window open 1
Middle ear space 1
Facial nerve 1
Malleus-incus complex 1
Mastoid pneumatization 1
Incus-stapes connection 1
Round window 1
External ear 1
Total Possible Score 10

Usually, a candidate must score with a 7 or higher out of 10 (with 10 being the optimal score achieved based on ear structure (middle/inner).
7 out of 10 means there is a 70% chance the patient will achieve normal to near normal hearing
8 out of 10 means there is a 80% chance the patient will achieve normal to near normal hearing
9 out of 10 means there is a 90% chance the patient will achieve normal to near normal hearing and so on…

Often times, if the score is below a 7 the individual may not be considered a candidate because the outcome of the surgery would either be risky or not a success.  In this case, a BAHA or bone anchored auditory implant may be suggested as the best option for better hearing.

3. The option for an ossicular replacement prosthesis:  A CT scan may reveal that some of the inner ear structures are missing or malformed.  Depending on the actual anatomy of the ear, it is possible that an ossicular prosthesis can be used to replace one of the missing or damaged bones still allowing the surgeon to restore hearing through canalplasty.  A prosthetic ear bone or replacement prosthesis can be made of two materials, titanium or hydroxyapatite.  In fact, even if an individual rates a 6 out of 10 on the “J” scale, it still may be possible for an individual to be a candidate for canalplasty based on their individual anatomy of the ear.  .Sometimes, a decision can depend on the anatomy that is seen at the time of surgery as a CT scan may not always reveal that all inner ear structures are present.

4.  Appropriate age:  It is suggested to wait until an individual is old enough for canalplasty for many reasons.  One reason is to wait until at least five years of age because at this time, the child is more cooperative and can sit very still when packing materials are removed post surgery in order to ensure a successful result.  Another reason would be to wait until the child is older in hopes that bony growths don’t develop as a result of the surgery causing damage to the ear canal such as causing the canals to collapse and then risk having to have a revision surgery later to restore the damage.  However, canalplasty has been performed on many children between the ages of 2 and 3 and have been successful.  The earliest typical age that a child can have canalplasty is at age 3, usually when considering Medpor outer ear reconstructive surgery.  Although, if a child is suffering from a cholesteatoma, when the cholesteatoma is removed, the surgeon may decide to perform canalplasty during that surgery if everything is anatomically sound and the child has a “normal inner ear.

*  Note:  Canalplasty is a very intricate and extremely detailed procedure that only few surgeons are willing to perform.  Always seek a second or even third opinion when considering canalplasty and request that more than one skilled surgeon at canalplasty read your CT scan.

For more detailed information on Canalplasty, please reference the following articles:

Gray L, Kesser BW, and Cole EA.  Understanding speech in noise after correction of congenital unilateral aural atresia: effects of age on the emergence of binaural squelch but not in use of head-shadow.  International Journal of Pediatric Otorhinolaryngology  2009;73(9):1281-7.

Oliver ER, Hughley BB, Shonka DC, Kesser BW.  Revision Aural Atresia Surgery:  Indications and Outcomes. Otol Neurotol. 2011;32(2):252-8.

DeAlarcon A, Jahrsdoerfer RA, Kesser BW*.  Congenital Absence of the Oval Window:  Diagnosis, surgery, and audiometric outcomes.  Otol Neurotol 2008;29(1):23-8.

Dobratz E, Rastogi A, Jahrsdoerfer RA, and Kesser BW*.  To POP or not:  Ossiculoplasty in congenital aural atresia surgery.  Laryngoscope 2008;118(8):1452-7.

Shonka DC, Jahrsdoerfer RA, Kesser BW*.  The Jahrsdoerfer Grading Scale in Surgery for Congenital Aural Atresia.  Arch Otolaryngol Head Neck Surg 2008;134(8):873-7.

You may also visit www.atresiarepair.com

 




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