Auricular Reconstruction: Modifications to Classification and Surgical Approach

Abstract

PURPOSE: One of the primary treatments for microtia is two-stage autogenous auricular reconstruction. The first stage involves a costal cartilage framework inset, and the second stage elevates the framework using fascial flaps, wedge cartilage grafts, and skin grafts. We present modifications to the conceptual classifications and surgical approach to auricular reconstruction with a focus on small concha-type microtia. MODIFICATION OF TECHNIQUE: 1) Microtia is classified into four sub-categories: lobule type, conchal type, small concha-type, and anotia. Planning the surgical approach begins with accurately identifying the category. Small concha-type microtia is often overlooked or thought to be a simple indentation in the conchal bowl region. The small concha is often a cavity, instead of an indentation, and located anteriorly to the normal conchal bowl. 2) The proper location of the ear can be determined by constructing an ‘auricular rectangle,’ a term coined by the senior author that utilizes multiple topographic references of the unaffected side in unilateral microtia: top of upper helix, caudal end of lobule, Frankfurt Horizontal line, shape of hairline, and face mask. If the face is asymmetrical like in severe hemifacial microsomia, identification of the auricular rectangle is more challenging and perfect symmetry is less attainable. Identifying the proper location of the ear is crucial to gauge if the vestige is in a surgically-usable location. 3) Surgical technique has evolved from a V- to W-shaped incision along the posterior surface of the auricle to maximize the skin surface area and create the deep concha. The W-shape also creates a superior advancement of the vestige. If the vestige is located at the same height as the unaffected side, the flap is more U-shaped. Additionally, the W-shape can be made asymmetric to create the desired 10-15 degree posterior inclination of the ear framework. 4) The hallmark of small concha-type microtia is that the small concha is not located in the correct anatomic location, so the skin flap elevated off the indent is too anteriorly positioned to be used for the tragus as much of the literature suggests. The small concha skin pocket should instead be excised. 5) After vestigial cartilage is removed and the cartilage framework is inserted around the subcutaneous pedicle of W-flap, the anterior lobule flap and transposed W-flap are closed. Temporary suction is applied to adhere the skin envelope to the framework. The final location and posterior inclination of the ear is determined, which reveals the areas of redundant skin, typically the anterior helix. Although conventional teachings do not include skin trimming, the senior author finds that horizontal wound closure has been successful in providing uninterrupted blood supply while preventing ischemia after years of training under Satoru Nagata and years of independent practice. CONCLUSION: These modifications advance our understanding of microtia classifications and how the surgical approach can be tailored to best utilize each component of the vestige. The functional outcomes of auricular reconstruction are especially important in light of the coronavirus disease 2019 (COVID-19) pandemic where the ability to wear masks relies on external ear function.