OUTER EAR DISEASE

Microtia

Anatomy of auricle *From The Ear comprehensive otology

Microtia

Classification of Microtia Grade I: A slightly small ear with identifiable structures and a small but present external ear canal Grade II: A partial or hemi-ear with a closed off or stenotic external ear canal producing a conductive hearing loss Grade III: Absence of the external ear with a small peanut vestige structure and an absence of the external ear canal and ear drum Grade IV: Absence of the total ear or anotia

Microtia IV I II III

Etiology Known causes Risk factor Thalidomide(啶酮) Isotretinoin(异维甲酸) Genetic Risk factor Diabetes The occurrence of microtia is usually a random, sporadic event, and it is important for the parents to understand that the deformity was not caused by anything the mother did before or during the pregnancy

Epidemiology Occurs 1 in 7,000 to 8,000 infants Occurs more often in right ears Occurs more often in males Higher incidence in Hispanics and Asians than in blacks and whites Fewer than 15% with positive family history Associated with other congenital malformations Cause is multifactorial. Facial cleft/ cardiac defect > anophthalmia/ microphthalmia > limb reduction defects/ severe renal malformation > holoprosencephaly 8

Surgery options canal reconstruction auricular reconstruction Ear canal reconstruction is unnecessary and overcomplicated Very good hearing is possible with modern hearing aids auricular reconstruction Rib Cartilage Graft Reconstruction a polyethylene plastic implant

Microtia reconstruction History Dr. Tanzer 1959 1st article on auricular reconstruction with autogenous rib cartilage, 6 stages procedure Dr. Brent 1974 4 stages procedure, foremost authority on auricular reconstruction Dr. Nagata 1985 2 stages procedure

Rib Cartilage Graft

The ear frame before it is assembled A polyethylene plastic The ear frame before it is assembled A Nylon Carving Block is available for purchase from Porex for use in contouring MEDPOR Biomaterial. Avoid placing the porous implant material on surgical drapes or other fibrous material that may shed particles on the implant. Photo of implant components on a surgical drape. Caution: The porous implant material should not be placed on surgical drapes or other fibrous material that may shed particles on the implant. 12

Tissue engineering

Long term result

Long term result

Principles Hearing External canal Age testing is first done to determine if the inner ear is intact and hearing is normal External canal to determine if a canal exists, by CT scan. (if a canal is not visible externally) Age The earliest age surgery can be attempted is age 3 for Medpor and 6 for Rib Cartilage Grafts. However a later age recommend, 8-10 when the ear is full adult size

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