Discussion

Surgery for atresia of the external auditory canal has undergone vast evolution since the first documented attempt at correction by Kiesselbach in 1883.1 Improvements in imaging and thus patient selection, facial nerve monitoring, grafting techniques, and drill technology have enabled many children to attain functional hearing without the use of amplification. Closure of the air-bone gap to within 30 dB has been achieved in upward of 80% of selected patients.3'8 Nevertheless, not all children are candidates for atresiaplasty. Contraindications to atresiaplasty include poor sensorineural function as documented on brainstem evoked response audiometry, a closed oval window, a facial nerve that courses on the oval window, no aeration of the middle ear space,18 and a poorly pneumatized mastoid (best seen on HRCT in the coronal projection).

Controversy remains over whether children with unilateral atresia should undergo surgery. In the past, Schuknecht,11 Crabtree,12 and Bellucci13 have recommended against operating on children with unilateral atresia, arguing that the benefit to be gained is minimal and unappreciated in the presence of a contralateral normal hearing ear. Hearing results at that time were unpredictable and often did not approach the 20-dB air-bone gap needed for useful hearing in the atretic ear.11 Risks of surgery, including facial nerve injury, also precluded operating on the unilateral atretic ear. In a recent review of more than 1000 operations for aural atresia with and without cholesteatoma, 10 patients (1%) suffered facial nerve injury.17 In nine patients, recovery had occurred by 7 months; the last patient had a facial nerve transection during the skin incision. These investigators identified five situations in which the facial nerve was most vulnerable: (1) skin incision, (2) dissecting in the glenoid fossa, (3) during the canalplasty, (4) transposing the facial nerve, and (5) dissecting soft tissue of the preauricular area.17

Other investigators have advocated atresiaplasty when the patient is old enough to give his own consent.14,19 They have cited moderate rates of restenosis and otorrhea (especially with the mastoidectomy approach) that argue against opening the ear; this approach often results in a draining radical cavity.

Complications of atresia surgery include high frequency sensorineural hearing loss (5%), total sensorineural hearing loss (2%), facial nerve palsy (1%), tympanic membrane graft lateralization (5 to 15%), and restenosis (5 to 15%).3,4 The incidence of major complications (total SNHL and facial nerve injury) has decreased over the years, but the other complication rate has essentially remained unchanged. The decision to operate on the unilateral atretic ear must weigh these potential complication rates along with the possibility of a draining ear. Nevertheless, with excellent preoperative imaging, improved surgical techniques, and advances in technology (i.e., laser), we believe that the results of atresia surgery are now more predictable. Closure of the air-bone gap to within 30 dB in the properly selected patient can be consistently achieved. A recent review examining the long-term stability of hearing results in patients operated on for aural atresia shows some dropoff in hearing thresholds (SRT) over time, however.16 Additional long-term follow-up studies are necessary to document and confirm these hearing results.

Wound complication rates, including otorrhea and restenosis, have stabilized or dropped over time. These potential complications can often be averted with office care. We stress the importance of a cooperative patient in the postoperative setting. Cleaning and manipulation of the ear are necessary; a beautiful result lost in the postoperative period from poor patient follow-up or cooperation serves no one. Most children do very well with cleaning, but an assessment should be made before surgery as to the child's willingness to sit in the chair and have the ears examined.

Using similar grading systems, De la Cruz, (Chan-drasekhar et al.4) and Jahrsdoerfer8 have argued for atresia surgery in selected children with unilateral atresia. A recent literature review also supports this position.15 Again, anatomic candidacy is predicated on temporal bone pneuma-tization, facial nerve course, inner ear morphology, stapes/ oval window appearance on HRCT, as well as documentation of the functional integrity of the inner ear. In the hands of an experienced otologic atresia surgeon with an anatomically favorable patient who (with the parents) understands the risks of potential complications and need for postoperative care, atresiaplasty in the patient with unilateral atresia is a rewarding operation for both surgeon and patient. The healed ear can be treated as a "normal" ear without restrictions on perspiration or water. Surgical correction of unilateral aural atresia offers the benefits of a clean, dry ear with binaural hearing, including sound localization and improved hearing in noise.

REFERENCES

De la Cruz and Kesser—CHAPTER 71

1. Jahrsdoerfer RA. Congenital atresia of the ear. Laryngoscope 1978;88:1

2. Jafek BW, Nager GT, Strife J, et al. Congenital aural atresia: an analysis of 311 cases. Trans Am Acad (Ophthalmol Otolaryngol 1975;80:588

3. De la Cruz A, Linthicum FH Jr, Luxford WM. Congenital atre-sia of the external auditory canal. Laryngoscope 1985;95:421

4. Chandrasekhar SS, De la Cruz A, Garrido E. Surgery of congenital aural atresia. Am J Otol 1995;16:713

5. Cole RR, Jahrsdoerfer RA. The risk of cholesteatoma in congenital aural stenosis. Laryngoscope 1990;100:576

6. Lambert PR. Congenital aural atresia. In: Byron J. Bailey, eds. Head and Neck Surgery—Otolaryngology. Philadelphia: JB Lippincott; 1993:1579

7. Ballachandra BB. Developmental anatomy of the outer ear. In: BB Ballachanda, ed. The Human Ear Canal. San Diego: Singular Publishing; 1995:8

8. Jahrsdoerfer RA, Yeakley JW, Aguilar EA, et al. Grading system for the selection of patients with congenital aural atresia. Am J Otol 1992;13:6

9. Jahrsdoerfer RA, Kesser BW. Issues on aural atresia for the facial plastic surgeon. Facial Plast Surg 1995;11:274

10. Malony TB, De la Cruz A. Surgical approaches to congenital atresia of the external auditory canal. Otolaryngol Head Neck Surg 1990;103:991

11. Schuknecht HG. Congenital aural atresia. Laryngoscope 1989; 99:908

12. Crabtree JA. Congenital atresia: case selection, complications, and prevention. Otolaryngol Clin North Am 1982; 15:755

13. Bellucci RJ. Congenital aural malformations: diagnosis and treatment. Otolaryngol Clin North Am 1981;14:95

14. Mattox DE, Fisch U. Surgical correction of congenital atresia of the ear. Otolaryngol Head Neck Surg 1986;94:574

15. Trigg DJ, Applebaum EL. Indications for the surgical repair of unilateral aural atresia in children. Am J Otol 1998; 19:679

16. Lambert PR. Long-term hearing results in congenital aural atresia surgery. Laryngoscope 1998;108:1801

17. Jahrsdoerfer RA, Lambert PR. Facial nerve injury in congenital aural atresia surgery. Am J Otol 1998;19:283

18. Lambert PR. Major congenital ear malformations: surgical management and results. Ann Otol Rhinol Laryngol 1988; 97:641

19. Glasscock ME III, Scwaber MK, Nissen AJ, Jackson CG. Management of congenital ear malformations. Ann Otol Rhinol Laryngol 1983;92:504

20. Jahrsdoerfer RA. Congenital malformations of the ear: analysis of 94 operations. Ann Otol Rhinol Laryngol 1980; 89:348

Unilateral congenital aural atresia represents one of the most complex and challenging problems that an otolaryngologist may have to face. The surgical procedure itself is fraught with potential pitfalls such as facial nerve paralysis and sensorineural hearing loss. There are differing schools of thought concerning the repair of congenital unilateral aural atresia; one school of thought is represented by Crabtree,1 who states that "one does not usually operate in cases of unilateral atresia until the patient is an adult and expresses the desire for surgery." The other school of thought is represented by Jahrsdoerfer et al.2 who writes that "whether the ear malformation is unilateral or bilateral plays no part in our selection process. Because we believe that hearing results are predictable, we operate on unilateral atresia patients routinely." The underpinnings of and the differences between these two surgical beliefs are in part philosophical, but another part rests in technological advances that have allowed for greater facility in predicting the results of surgery. This chapter, discusses the controversy over managing patients with unilateral congenital aural atresia by describing the preoperative evaluation that goes into formulating a treatment algorithm and our rationale for offering unilateral atresia repair to pediatric patients and their families.

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