External Auditory Canal Atresia Treatment & Management

Management of external auditory canal atresia (EACA) must begin with early identification and discussion of the developmental, surgical, and educational issues specific to each child. A team approach to management is essential.

Medical care must encompass care of OM and language development.

• Understanding the impact of hearing loss caused by the atretic ear canal is important. Consider the educational impact of hearing impairment in the treatment plan for each child. The importance of restoring early hearing in these patients cannot be underestimated. Once the indication arises regarding the potential for hearing loss, early hearing testing and subsequent early placement of hearing aids greatly facilitate language outcomes. Some centers perform ABR testing as soon as feasible and attempt to place hearing aids by age 6 months at the latest.
• Bilateral atresia usually requires surgery to restore hearing. Before surgery, and sometimes afterward, patients should be fitted with appropriate amplification, such as bone-conduction hearing aids. Surgical intervention on the first ear generally occurs around age 4-5 years. A study that examined the binaural interaction of bone-conducted auditory brainstem responses in children with EACA concluded that fitting of a bilateral bone conduction hearing aid may be a way to optimize binaural hearing and sound lateralization.^[6] Interestingly, the actual anatomical configurations of the external auditory canal have been demonstrated to affect the gain distribution and contribution to audition.^[7]
• Not all patients with unilateral atresia require surgery. Hearing, learning, and social issues must be considered for audiologic and surgical decision making.
• Additional amplification measures include a bone-anchored hearing aid (BAHA),^[8] which is a percutaneous device that conducts sound via bone. Recently, a group in Italy commented that in bilateral atresia, they feel the results from BAHA are superior and should be considered as the initial management.^[9] In children who are too young for a percutaneous device, the BAHA softband is a new strategy. Further developments to augment hearing include the use of a fully-implantable hearing aid, which potentially aids patients with malformations of the middle ear.^[10] A novel device, referred to as a floating mass transducer, may have potential to augment hearing in this group of patients.^[11] The floating mass transducer is a surgically implantable device on the round window and has been shown to augment the air-bone gap in these patients.^[12]

The goal of surgery is to create a safe and hearing ear. Experience with audiologic and medical assessment of pediatric ear disorders and otologic surgery in children is important. Safety pertains to preventing or treating cholesteatoma and, rarely, OM and its complications. Hearing requires the creation of an external auditory canal, tympanic membrane, and ossicles that can transmit sound with or without amplification (ie, hearing aid).

Consider surgery after multidisciplinary discussion with the family concerning risks, alternatives, and benefits and after comprehensive evaluation, including radiographic staging using CT. As with all surgical counseling, maintain open discussion of realistic goals and expectations among members of the medical team and the family. For reasons of social stigma, educational deficit, and perioperative care, the age at which surgery is indicated for noninfectious reasons (ie, not cholesteatoma or otitis) is around early school age, or 5 years. Anatomic growth by this age also allows safer surgery. Above all, proper patient selection for correction of the atresia is crucial. The dictum primum non nocere ("first, do no harm") must be foremost in counseling families.

• In bilateral EACA, corrective surgery, even if only for one ear, is usually beneficial.
• In unilateral EACA, some patients are not good candidates for surgical intervention.

  • Middle ear pneumatization is an important index of surgical success. One study in 1988 by Lambert found that patients with a middle-ear space less than 50% of the normal contralateral ear were poor surgical candidates.^[13] Lambert suggests that the chances for restoration of hearing is reduced in patients who have a middle ear space that is greatly reduced and do not have ossicles. He recommends against surgery for unilateral EACA in these patients. Indeed, studying the middle ear dimensions helps optimize surgical outcomes.^[14]
  • Others advocate operating in children with unilateral EACA only in the presence of a cholesteatoma or an infection of the atretic ear. Some also argue that intervention should not occur until the child is aged 18 years or when the child is able to accept the risks and benefits and understand the alternatives of treatment options. Lambert believes that the advantages of binaural (bilateral) hearing justify the limited surgical risks in properly selected patients. His specific criteria include normal facies, radiographic demonstration of roughly equal middle-ear spaces, and the presence of an ossicular mass.
• Facial nerve anatomy is an important consideration. As Kiesselbach discovered in 1882, the course of the facial nerve is aberrant in patients with atresia of the EAC. Preservation of the nerve is crucial, and CT scanning may be able to delineate the course of the nerve. Regardless of radiography, the surgeon's most important task is to first think of the facial nerve during dissection. Intraoperative nerve monitoring helps. Risk factors of aberrant facial nerve anatomy are the presence of EACA itself, poor mastoid tip development (seen often in EACA), and high degree of microtia. Documentation of facial nerve function, with objective measures if needed, is critical before planning surgery.
• Jahrsdoerfer proposed a grading system to predict which patients would potentially have the greatest benefit from surgical intervention for correction of an atretic external auditory canal.^[15] In this system, points were assigned for normal structures on the basis of CT scanning. Two points were given for the presence of a stapes, whereas 1 point was assigned for the presence of oval window, middle-ear space, facial nerve, malleus/incus complex, pneumatization of the mastoid, incudostapedial joint, round window, and normal external ear appearance. With a score higher than 8, Jahrsdoerfer achieved a postoperative hearing threshold of less than 20 decibels (dB) in 80% of patients. Furthermore, he concluded that patients with a score of less than 6 would most likely benefit more from nonsurgical management.
• The assistance of image guidance, using CT-based or MRI-based surgical navigation systems, is not currently routine. Exploration and removal of cholesteatoma is important in treating this benign epidermal inclusion, which has the potential to cause significant local erosion or regional complications (eg, brain abscess, facial nerve palsy). Surgery is indicated by the presence of a cholesteatoma, whether suggested by a draining fistula, keratin debris in the ear canal, or CT findings.
• Timing of microtia versus atresia surgery must be considered in patients who present with complete absence of the pinna. In these cases, Glasscock feels that the otolaryngologist should perform surgery before the plastic surgeon.^[16] Although this is a controversial area, communication and teamwork between the pediatrician, otolaryngologist, and plastic surgeon are especially important in this case.
• Surgical repair requires general anesthesia. To allow optimal facial nerve monitoring and stimulation during surgery, neuromuscular blockade is avoided with the exception of a short-acting paralytic to aid in the induction of general anesthesia. Surgical technique involves a postauricular incision, followed by creation of a new ear canal. In the authors' practice, skin grafting from the buttock or thigh is used to line the new EAC. Allogenic human dermis may be used as well as a matrix for reepithelialization of the EAC. Middle-ear work to establish a functional middle ear mechanism may require the placement of a prosthesis. The middle ear and ear canal are packed with absorbable packing. EAC packing may include nonabsorbable materials (gauze), which may require general anesthesia for optimal removal.
• Staged EAC debridement 2-4 weeks after the initial surgery may be required for the child's comfort and for optimal surgical results.
• In Slovenia, Battelino et al described a small case series of patients who had success in maintaining patency of the EACA repair with topical application of mitomycin-C.^[17] They reported success with both congenital and secondary fibrotic atresias of the EAC.
• Operating on a patient with EACA and an infected middle ear is challenging. A research group from Japan detailed their modified transmastoid approach.^[18] They advocate visualization of the antrum, sinodural angle, and digastric ridge via the canal-open method, avoiding facial nerve injury, followed by preparation of a relatively large external ear canal with reconstruction of the posterior wall of the external ear canal. They find this method advantageous for minimizing postoperative complications such as restenosis of the new ear canal and postoperative middle ear infection. Interestingly, to mitigate infections during reconstruction, it was suggested that the bacterial flora be studied preoperatively, with administration of targeted antibiotics prophylactically to reduce the bacterial burden prior to surgery.^[19]

A multidisciplinary team approach is advised and should include the pediatrician, plastic surgeon, otolaryngologist (ie, head and neck surgeon), audiologist, speech pathologist, educational consultant, social worker, and psychological counselor.

Consultation with a geneticist is important in guiding evaluation for concomitant medical problems, especially in children who have been diagnosed with a syndrome, and for calculating the risk of EACA to reoccur in subsequent generations. The option to bank blood for future genetic testing may be offered.

No specific dietary therapies have been established to aid children with EACA.

In the authors' practice, flying is not restricted because the middle ear and canal have absorbable packing.