A case of microtia with bilateral conductive hearing loss with unusual findings
Keywords:Microtia, Stapes agenesis, Facial nerve, Conductive hearing loss
Microtia refers to a group of congenital auricle malformations that range in severity from minor partial structural abnormalities to full auricle absence (anotia). A 17-year-old female, who was also a known case of left ear microtia presented to OPD with chief complaint of reduced hearing from both ears since 4 years. Examination showed Left ear microtia with narrow canal with retracted tympanic membrane while right ear had a normal pinna and canal with grade 3 retraction present in the tympanic membrane. In pure-tone audiometry (PTA) a conductive hearing loss of 57 dB in the right ear and 52 dB in the left ear, and impedance audiometry showed a curve of "Ad" and bilaterally ipsilateral reflexes were found to be absent. During exploratory tympanotomy, intraoperatively facial nerve was found to be low lying over the promontory, showing an abnormal course. A piece of cartilage was placed over the posterosuperior region. Temporalis fascia graft was placed over it. Any such case that has a congenital anomaly like microtia should not be planned for any kind of surgical intervention as they might have abnormal findings like an aberrant course of the facial nerve, and any kind of intraoperative manipulation with the ear might further increase the complications of the patient like facial nerve paresis. These patients should be properly assessed and counselled to directly go for a hearing aid rather than undergo any kind of surgical risk or complication.
Carey JC, Park AH, Muntz HR. External ear. In: Stevenson RE, ed. Human Malformations and Related Anomalies. Oxford, New York: Oxford University Press. 2006:329-38.
Castilla EE, Orioli IM. Prevalence rates of microtia in South America. Int J Epidemiol. 1986;15(3):364-8.
Hunter A, Frias JL, Gillessen-Kaesbach G, Hughes H, Jones KL, Wilson L. Elements of morphology: standard terminology for the ear. Am J Med Genet A. 2009;149A(1):40-60.
Suutarla S, Rautio J, Ritvanen A, Ala-Mello S, Jero J, Klockars T. Microtia in Finland: comparison of characteristics in different populations. Int J Pediatr Otorhinolaryngol. 2007;71(8):1211-7.
Alasti F, Van Camp G. Genetics of microtia and associated syndromes. J Med Genet. 2009;46(6):361-9.
Mastroiacovo P, Corchia C, Botto LD, Lanni R, Zampino G, Fusco D. Epidemiology and genetics of microtia-anotia: a registry based study on over one million births. J Med Genet. 1995;32(6):453-7.
Shaw GM, Carmichael SL, Kaidarova Z, Harris JA. Epidemiologic characteristics of anotia and microtia in California, 1989-1997. Birth Defects Res A Clin Mol Teratol. 2004;70(7):472-5.
Harris J, Källén B, Robert E. The epidemiology of anotia and microtia. J Med Genet. 1996;33(10):809-13.
Canfield MA, Langlois PH, Nguyen LM, Scheuerle AE. Epidemiologic features and clinical subgroups of anotia/microtia in Texas. Birth Defects Res A Clin Mol Teratol. 2009;85(11):905-13.
Forrester MB, Merz RD. Descriptive epidemiology of anotia and microtia, Hawaii, 1986-2002. Congenit Anom (Kyoto). 2005;45(4):119-24.
Bergeron M, Côté M. Bilateral stapes agenesis: What can we find? Acta Oto-Laryngologica Case Reports. 2017;2(1):47-51.
Gerhardt HJ, Otto HD. The intratemporal course of the facial nerve and its influence on the development of the ossicular chain. Acta Otolaryngol. 1981;91:567-73.
Jahrsdoerfer RA. Embryology of the facial nerve. Am J Otol. 1988;9:423-6.
Keskin G, Üstündağ E, Almaç A. A case of congenital bilateral stapes agenesis. Turkish J Ear Nose Throat. 2003;11(6):175-8.