Approach Considerations
It is not uncommon to refer the patients to a geneticist for evaluation of a syndrome associated with microtia and atresia. These specialists may also offer the parents an opinion about having another child with microtia.
Imaging Studies
Microtia is rarely noticed on antenatal ultrasonography (US), primarily because of the complexity of the fetal ear and the inherent nature of conventional two-dimensional (2D) US. Some authors suggest the use of three-dimensional (3D) US to provide a better examination of the fetal ear for purposes of antenatal diagnosis and genetic counseling. The image below is a 3D sonogram, with the arrow indicating the microtia.
Computed tomography (CT) of the ears is not recommended in children younger than 4 years. Obtaining a CT scan at an earlier age does not allow any earlier surgical intervention and therefore serves only to irradiate the child's head unnecessarily. Obtaining the scan just before the pinna reconstruction is recommended so as to facilitate counseling of the patient about candidacy for ear-canal and middle-ear surgery. The image below shows the lack of an ear canal on the left side.
Arrow in CT scan indicates lack of ear canal (atresia) on left side. Note normal ear canal on right side.
Procedures
An auditory brainstem response (ABR) test is recommended soon after birth to evaluate inner-ear (cochlear) function on both sides.
Frequent otologic evaluations are essential to rule out other possible problems, such as otitis media in the good ear. In the case of ear-canal narrowing or stenosis, it is important be aware of foul-smelling drainage. This could be a sign of a cholesteatoma growing medial to the stenosis.
Aggressively treat middle-ear effusions of the normal ear to optimize the hearing status of the child and avoid speech delay. An ABR test is usually recommended approximately 3-6 months later. If the child is cooperative, audiologic testing can then be performed by sound-field testing and eventual bilateral pure-tone audiometry. Routine scheduled audiologic follow-up testing should be continued.
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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.
