Diagnosis Kaga K, Asato H (eds): Microtia and Atresia – Combined Approach by Plastic and Otologic Surgery. Adv Otorhinolaryngol. Basel, Karger, 2014, vol 75, pp 10–12 (DOI: 10.1159/000350495)

Classification of Shapes (Auricle/ External Auditory Canal) Yasutoshi Suzuki  Department of Plastic Surgery, Dokkyo Medical University, Shimotsuga-gun, Tochigi, Japan

Microtia is a congenital anomaly of the auricle in which the components of the auricle are small or missing. The severity and states vary. Its incidence is 1 in 10,000–15,000 births, and male patients outnumber female patients (approximately 2:1). Microtia develops more frequently on the right than the left side (approximately 5:3), and the reported incidence of bilateral microtia is approximately 10%. Many cases are complicated by stenosis or occlusion of the EAC in addition to the morphological abnormality of the auricle. Auricular shape in microtia can be classified by conventional methods using the characteristics of the residual auricle, and by methods using qualitative differences related to embryology in addition to quantitative differences. The former includes the three-grade classification of Marx [1] and the five-grade classification of Ogino et al. [2] (table 1), and the 10-type classification of Fukuda [3] is an example of the latter. These criteria are widely used in Japan for diagnosis, treatment and surgery of microtia. In addition, Asato and Kaga classified microtia into five types from the perspective of simultaneous reconstruction of the EAC with auricular projection, in addition to auricular reconstruction by costal cartilage transplantation (fig. 1, 2). The incidence of lobule-type (a) microtia is highest, accounting for approximately 60% of cases, followed by the concha-type (c) and the small-concha type (b), with a combined incidence of approximately 15%. Atypical-type (d) and anotia-type (e) microtia, which are not included in a, b or c are rare.

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Classification of Shapes of the Auricle

Asato and Kaga’s classification Lobule type Small concha type Concha type Atypical type

Marx’s classification

Ogino’s classification

Anotia

Grade I

Grade I

Grade II

Grade III

Grade II Grade IV Grade V

Grade III

Fig. 1. Correlation between classification systems for microtia.

a

b

c

d

e

Fig. 2. Classification of microtia according to Asata and Kaga. a Lobule type. b Small concha type. c Concha type. d Atypical type. e Anotia type.

Table 1. Clinical classification of microtia Marx’s classification Grade I Auricle shows mild deformity and is slightly smaller than normal, but each part can be distinguished Grade II Auricle shows middle class deficit and only partial structure of helix is retained Grade III Auricle shows severe deformity with only skin upheaval

Classification of Shapes Kaga K, Asato H (eds): Microtia and Atresia – Combined Approach by Plastic and Otologic Surgery. Adv Otorhinolaryngol. Basel, Karger, 2014, vol 75, pp 10–12 (DOI: 10.1159/000350495)

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Ogino’s classification Grade I Auricle is little smaller than normal, but the structures of each part of the ear are recognizable Grade II Auricle is smaller than normal with small conchal cavity, tragus, and ear lobe Grade III Auricular configuration is absent; small auricular remnant and ear lobe exist without conchal cavity and tragus Grade IV Only ear lobe Grade V Anotia (complete absence of auricle)

Classification of the External Auditory Canal by Shape

Many cases of microtia are complicated by atresia of the EAC, which may occur as complete occlusion or EAC stenosis, which is incomplete occlusion. Atresia or stenosis of the EAC is either limited to cartilage or osseous occlusion. Stenosis is classified as: (1) stenosis of the entire bone, (2) stenosis of the lateralis osseous, and (3) stenosis of the cartilage. Osseous occlusion is often observed in microtia patients and is commonly complicated by a middle ear anomaly. In such cases, a deformation or deficit of the auditory ossicle or osseous adhesion to the surrounding tissues is observed, and formation of the middle ear cavity and development of the tympanic antrum are variable. From the viewpoint of treatment and prognosis, classification of cases by combining development of the middle ear with the occlusion of the EAC has been reported. The grading system of Jahrsdoerfer et al. [4] is especially useful, where higher scores indicate expected improvement of auditory acuity (see ‘Imaging diagnosis’, this vol., p. 15).

References   3 Fukuda O: Shoujishou no bunrui; in Soeda S (eds): Zusetsu rinshou keiseigekagaku kouza 4. Tokyo, Medical View, 1988, pp 16–17.   4 Jahrsdoerfer RA, Yeakley JW, Aguilar EA, et al: Grad­ ing system for the selection of patients with congenital aural atresia. Am J Otol 1992;13:6–12.

Yasutoshi Suzuki Department of Plastic Surgery, Dokkyo Medical University 880 Kitakobayashi, Mibu-Machi Shimotsuga-gun, Tochigi 320-0293 (Japan) E-Mail [email protected]

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Suzuki Kaga K, Asato H (eds): Microtia and Atresia – Combined Approach by Plastic and Otologic Surgery. Adv Otorhinolaryngol. Basel, Karger, 2014, vol 75, pp 10–12 (DOI: 10.1159/000350495)

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 1 Marx H: Die Missbildungen des Ohres. DenkerKahler’sche Handbuch der Hals-Nasen und Ohrenheilkunde, Gehörogan 1. Berlin, Julius Springer, 1926, pp 131–169.   2 Ogino Y, Nishimura Y, Horii M, et al: Congenital microtia – multidirectional tomographic and remnant auricular forms. Pract Otol 1976;69:792–801.

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