In 1977 Tanzer proposed a clinical classification of auricular defects which is often used in publications since that time. He classified the congenital ear defects according to the approach necessary for their surgical correction.I. Anotia
II. Complete hypoplasia (microtia)
A. With atresia of external auditory canal
B. Without atresia of external auditory canal
III. Hypoplasia of middle third of auricle
IV. Hypoplasia of superior third of auricle
A. Constricted (cup or lop) ear
C. Hypoplasia of entire superior third
V. Prominent ear
The term aural atresia refers to the absence of the ear canal. Patients who have microtia usually, but not always, also have aural atresia. Patients who have aural atresia have no hearing on that side but usually have completely normal hearing in the normal ear. Patients who lack the ear canal also have structural abnormalities of the middle ear with absence of the eardrum and incomplete formation of the small middle ear bones, which allow conduction of hearing through the middle ear. Microtia and aural atresia tend to occur together because the outer ear and the middle ear evolve from a common embryologic origin.
Nagata’s technique involves two stages. It was first introduced in 1993 and has undergone several possible technical refinements, depending on the type of microtia present (ie lobular, small concha, anotia, low hairline).In the first stage, the rib cartilage framework, which incorporates a tragal component, is placed in a subcutaneous pocket and the lobule is transposed. This first stage thus roughly corresponds to the first three stages in Brent’s sequence. Nagata uses the skin of the posterior lobule and mastoid to cover the conchal aspect of the construct. By converting the V-shaped posterior lobule incision used by Tanzer into a “W,” he also increases the surface area of skin available to cover the framework. Six months later the second stage is done. The construct is elevated and symmetry adjustments made.
Complications arising from surgical efforts to reconstruct the external ear may occur both at the ear reconstructive site and at the donor sites for tissue harvest. The complications associated with costal cartilage harvest include the immediate problems of the pneumothorax and atelectasis and the delayed issues of chest wall deformity and scarring. Complications at the ear reconstruction site include exposure of the cartilage framework due to overlying skin flap necrosis. This can be devastating to the reconstruction and may necessitate the complete removal of the framework. In cases of flap compromise, early intervention is mandatory for salvage of the reconstruction. More commonly, small areas of skin loss (less than 1 cm) may be dealt with conservatively with topical and systemic antimicrobial therapy, allowing the area to granulate and heal by secondary intent. Infection is not a common complication (0.5 percent), but it may stem from either construct exposure or pathogens in the vestigial external ear canal. As such, careful assessment of any pathologic findings in the middle ear, such as otitis or cholesteatoma, and preoperative cleaning of the canal are imperative. Hematoma is an infrequent complication (0.3 percent), but its occurrence can have devastating consequences. Long-term complications in the reconstructed ear primarily relate to extrusion of suture material and resorption of the cartilage framework, which may alter the shape and form of the auricular components.
- Surgical Procedures of the External Ear Canal and Ear; Dept. of Otolaryngology, UTMB, Grand Rounds; May 5, 1993; Kathleen McDonald M.D., Jeff Vrabec M.D., Melinda McCracken, M.S.
- Total reconstruction of the auricle: The evolution of a plan of treatment; Plast. Reconstr. Surg. 47: 523, 1971; Tanzer, R. C.
- Autogenous Rib Cartilage Reconstruction of Congenital Ear Defects: Report of 110 Cases with Brent's Technique; Plastic & Reconstructive Surgery. 104(7):1951-1962, December 1999; Osorno, Gabriel M.D.
- Auricular Reconstruction: Indications for Autogenous and Prosthetic Techniques; Plastic & Reconstructive Surgery. 107(5):1241-1251, April 15, 2001; Thorne, Charles H. M.D.; Brecht, Lawrence E. D.D.S.; Bradley, James P. M.D.; Levine, Jamie P. M.D.; Hammerschlag, Paul M.D.; Longaker, Michael T. M.D.
- Auricular Reconstruction for Microtia: Part II. Surgical Techniques; Plastic & Reconstructive Surgery. 110(1):234-251, July 2002; Walton, Robert L. M.D.; Beahm, Elisabeth K. M.D. (bottom two photo composites on technique from this article)
- Refinements in the Elevation of Reconstructed Auricles in Microtia; Plastic & Reconstructive Surgery. 117(7):2414-2423, June 2006; Tai, Yoshiaki M.D.; Tanaka, Shinsuke M.D.; Fukushima, Junichi M.D.; Kizuka, Yuichiro M.D.; Kiyokawa, Kensuke M.D.; Inoue, Yojiro M.D.; Yamauchi, Toshihiko M.D.