Physical Examination
Consultation regarding a patient born with microtia and atresia ideally should occur soon after birth. This allows the ear surgeon to discuss the options with the parents and to calm their fears and anxieties.
The initial examination consists of a detailed head-and-neck examination. The most important things to be determined in this examination are as follows:
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Type of microtia
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Presence or absence of atresia
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Size and location of the normal ear (in unilateral cases)
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Level of the hairline on each side
Although severe conductive hearing loss usually results from lack of an ear canal, the inner-ear function is almost always normal, resulting in some ability to hear on the affected side.
Because approximately 90% of children with microtia are affected only on one side, the contralateral ear is almost always normal, resulting in relatively normal speech development. During the initial consultation, the ear reconstructive surgeon should reassure the parents and outline the future management of their child's condition.
If microtia is the only developmental anomaly, the initial workup consists of evaluation of the child's hearing status. As previously stated, the inner-ear function is usually normal in patients with microtia and atresia. Also, the middle-ear status of the nonaffected ear is usually normal, resulting in overall normal hearing in the nonaffected ear.
Classification
Microtia is classified into four grades along a spectrum that extends from less severe (grade I) to total absence of the external ear (anotia).
Grade I
In grade I, the pinna is malformed and smaller than normal. Most of the characteristics of the pinna, such as the helix, triangular fossa, and scaphae, are present with relatively good definition (see the image below).
Microtia, grade I. Pinna is malformed and smaller than normal. Most characteristics of pinna (eg, helix, triangular fossa, and scaphae) are present with relatively good definition. Patient is also lacking ear canal (atresia).
Grade II
In grade II, the pinna is smaller and less developed than it is in grade I. The helix may not be fully developed. The triangular fossa, scaphae, and antihelix (anthelix) have much less definition (see the image below).
Microtia, grade II. Pinna is smaller and less developed than in grade I. Helix may not be fully developed. Triangular fossa, scaphae, and antihelix (anthelix) have much less definition.
Grade III
Grade III is considered the "classic" microtia. The pinna is essentially absent, except for a vertical sausage-shaped skin remnant. The superior aspect of this sausage-shaped skin remnant consists of underlying unorganized cartilage, and the inferior aspect of this remnant consists of a relatively well-formed lobule (see the image below).
Microtia, grade III. Pinna is essentially absent, except for vertical sausage-shaped skin remnant. Superior aspect of this sausage-shaped skin remnant consists of underlying unorganized cartilage, and inferior aspect consists of relatively well-formed lobule.
Anotia
In anotia, total absence of the pinna is observed (see the image below).
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Microtia, grade I. Pinna is malformed and smaller than normal. Most characteristics of pinna (eg, helix, triangular fossa, and scaphae) are present with relatively good definition. Patient is also lacking ear canal (atresia).
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Microtia, grade II. Pinna is smaller and less developed than in grade I. Helix may not be fully developed. Triangular fossa, scaphae, and antihelix (anthelix) have much less definition.
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Microtia, grade III. Pinna is essentially absent, except for vertical sausage-shaped skin remnant. Superior aspect of this sausage-shaped skin remnant consists of underlying unorganized cartilage, and inferior aspect consists of relatively well-formed lobule.
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Anotia (total absence of pinna).
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Three-dimensional sonogram of fetus with microtia.
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Arrow in CT scan indicates lack of ear canal (atresia) on left side. Note normal ear canal on right side.
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Arrow points to small incision. Average length is approximately 1.0-1.5 in. (2.5-3.5 cm), depending on experience of microtia surgeon and weight of child.
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Microtia rib cartilage used for patient with microtia. Very small (1.0-1.5 in.) incision is made on skin, and synchondrosis of ribs 6 and 7 is excised, as well as small cartilaginous segment of rib 8. Ribs 6-7 synchondrosis forms main framework, and tragus of ear and rib 8 forms rim or helix of ear.
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Incision should be as small as possible without jeapordizing visualization of cartilage. In this example, incision was only 0.75 in. (2 cm), which was sufficient to harvest cartilage for this child with right-side microtia and atresia.
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Incision should be as small as possible while still permitting excellent visualization of tissues. In this example, incision on right chest area was only 1 in. (2.5 cm), which was sufficient to harvest necessary cartilage to build ear of patient born with left-side microtia.
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Image shows carved cartilaginous framework (including tragus) from small portions of ribs 6, 7, and 8.
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Final portion of first stage of microtia surgery. Once cartilage is sculpted into shape of ear, it is inserted into skin pocket, and once suction is placed, new ear is evident. Note how color of new ear with cartilage technique is normal. There is no skin that has to be removed, and thus, sensation of ear is maintained as well. Earlobe will be mobilized into its future site in next stage of procedure. Video courtesy of Arturo Bonilla, MD.
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Patient shown underwent first stage of microtia surgery 1 week previously. Because cartilage framework is simply placed under skin pocket, note natural color of ear. No skin is removed with rib cartilage technique.
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Second stage consists of forming earlobe (otherwise known as transposition of lobule). Incision is made both in front of and behind skin vestige as shown. Skin vestige is then rotated into place via Z-plasty and spliced to cartilaginous framework that was sculpted during first stage.
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Patient shown underwent second stage of microtia surgery 2 weeks previously. Earlobe has been positioned into its permanent location, and conchal bowl has been deepened (as evidenced by shadow-effect of conchal bowl).
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Full-thickness skin graft is harvested from groin area in order to hide incision site.
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Third (separation and elevation) stage of microtia reconstruction. Swelling is normal and will decrease after several weeks, revealing fine detail of ear. Video courtesy of Arturo Bonilla, MD.
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Once microtic ear is separated and elevated, ears are symmetrical. Patient had classic grade III microtia and atresia. Photograph on right shows excellent separation from third stage.
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Patient with most common type of microtia (ie, grade III microtia and atresia) before surgical reconstruction.
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Patient with grade III microtia and atresia after surgical reconstruction with natural cartilage technique. Note how skin color remains normal. Sensation of skin also remains normal.
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Video shows how alloplastic polyethylene implant can fracture before it is used for microtia surgery. Lifelong risk of infection, rejection, or fracture is why most surgeons do not use this technique to treat microtia.
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Result after rib cartilage framework is placed under skin pocket. Note natural skin color of ear. Cartilage technique does NOT require skin graft placed over ear that will give it two-toned color effect.
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Printing of ear cartilage cells using 3D bioprinting is promising technique in microtia reconstruction.
