Decision Making

In the case of bilateral aural atresia, the primary concern is that of the development of normal speech and language. These children should be fitted early on with bone anchored hearing aids, and surgery should be strongly considered. In the case of unilateral aural atresia, a complete audiologic evaluation should be performed. Surgery is only a consideration if there is normal or near-normal sensorineural hearing loss in the atretic ear. Historically it has been felt that if the patient has normal hearing in one ear, then the effect on language and speech will not be greatly affected by the loss of hearing in the other ear. This premise has recently been called into question and there is debate currently over whether unilateral hearing loss can in fact create linguistic and cognitive deficits.6

As for the timing of repair of the unilateral atretic ear, there is a range of years during which it is considered acceptable to offer surgery, depending on the co-mitigating factors. In the face of atresia coupled with grade III microtia, we feel that the atresia repair should be delayed until after the auricular reconstruction so that the costal cartilage has a well-vascularized bed in which to be placed. As microtia repairs generally do not occur before the age of 6 years, the subsequent atresia repairs are then delayed until the patient is 7 or 8 years of age. If the atresia is in isolation, some authors (e.g., Crabtree1) assert that the repair should take place when the patient is old enough to understand the risks involved. Others believe that it is only necessary for the patient to be able to cooperate so that adequate postoperative care can be delivered.

The fear in operating on patients with unilateral aural atre-sia has historically rested in the inability to predict surgical success and the danger of injuring the facial nerve. The advent ofHRCT imaging and facial nerve monitoring have dramatically reduced these unknowns in atresia surgery and make it possible to offer surgical management based upon objective preoperative data and reasonable expectations of surgical outcome. HRCT has allowed for specific answers to crucial questions that affect the preopera-tive evaluation, such as the following: Is there a stapes? Is the oval window visible? Is the facial nerve identifiable in a predictable course? Jahrsdoerfer used HRCT to develop a 10-point system to predict the success rate for surgical repair.2 In his system, 2 points are given for an identifiable stapes, 1 point for the following findings: an open oval window, an identifiable middle ear space, a normal facial nerve, an identifiable malleus-incus complex, a well-pneumatized mastoid, an incus-stapes connection, a normal-appearing round window, and a normal-appearing external ear. A score of 8 signaled an 80% chance of success defined as a postoperative speech reception threshold of 10 to 25 dB. This point grading scheme has proved more clinically useful than Altmann's purely descriptive classification scheme.7 De la Cruz et al.4 have also proposed a classification scheme with an eye toward guiding surgical management.

If Jahrsdoerfer's grading system allowed for some measure of predictability in terms of surgical success, the advent of mod ern facial nerve monitoring has allowed for greater degrees of comfort with respect to avoiding potentially disastrous pitfalls. Although Jahrsdoerfer8 states that facial nerve monitoring is of little use in atresia surgery, many practicing otologists and oto-laryngologists believe that facial nerve monitoring remains an invaluable tool. The incidence of facial nerve injury after atresia surgery approximates 1%.5 This low incidence is due in part to the use of HRCT and preoperative knowledge of particular facial nerve anatomy. We attribute it to the use of intraoperative facial nerve monitoring, as well. Whether one advocates facial nerve monitoring, it is essential for the surgeon embarking on repair of aural atresia to have a sound knowledge of facial nerve anatomy and its potential aberrations.

Hearing Aids Inside Out

Hearing Aids Inside Out

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