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Features Departments Information |
  Bruce S. Bauer, MD
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Reconstruction of the external ear in microtia BRUCE S. BAUER, MD, FACS aFall 1996 THE SIZE, PROMINENCE and shape of people’s ears are as varied as the individuals on whom they appear. These variations are considered normal as long as the ears’ size and relationship to other facial features are in balance. However, even minor disturbances in balance or shape are immediately perceived as looking "wrong," and this perception can become the source of significant peer ridicule. For the child with microtia, the most severe of the congenital deformities, such an abnormality may be the source of intense shame and anguish. Not surprisingly, the surgical correction of this deformity that brings about an ear of near-normal size, shape and position can have a remarkably beneficial effect on the child’s self-esteem and body image. Given the delicate and complex form of the external ear, it is not surprising that the surgical construction of an absent or a near-total absent ear presents one of the greatest challenges faced by the reconstructive surgeon. Furthermore, because microtia occurs in about one in 6–8,000 births and is therefore a relatively common anomaly, constructing ears that closely approximate normal ones is a source of great satisfaction to everyone involved. The purpose of this brief article is to give an overview of this deformity, its anatomy, classification, timing of reconstruction and the basics of the reconstructive procedures used to correct it. A companion feature (Congenital Aural Atresia by Nancy M. Young, MD) discusses aspects of managing the hearing loss associated with absence or significant anomalies of the middle ear, a finding that is common in these patients. Anatomy and Classification of Microtia Microtia, the most severe of the congenital ear deformities, typically presents as part of a spectrum of branchial arch defects. Some microtic remnants are associated with little or no skeletal deformity, while others exist as part of the full manifestation of craniofacial microsomia.  FIGURE 1. The external ear presents a delicate three-tiered structure the key landmarks of which are named in this figure. Portions of these recognizable parts may or may not be present in the microtic ear. The term "micro" means small, and "otia" means ear. Hence when translated literally, "microtia" means small ear. In fact, in the majority of cases the microtic ear is no more than a bump of tissue with little resemblance to the complicated structure we recognize as the external ear (Figure 1). The microtic ear is typically classified according to the recognizable parts of the normal ear that are present. While many classifications exist, the one most widely used separates the deformity into lobular and conchal types.  FIGURES 2A, 2B. The classification of microtia is based on the recognizable parts of the external ear present in the vestige. These photographs show examples of the most common forms: A, Lolar microtia with a sausage-shaped vestige and B, Conchal remnant microtia with a portion of the concha, tragus and a larger lobular remnant. In both A and B, the canal meatus and canal are absent. The auricle in lobular microtia is typically sausage-shaped with the greater portion of the remnant being the vestige of the lobule or ear lobe. Usually, the external auditory canal and meatus are absent. In conchal remnant microtia, the remnant is larger and more recognizable; usually the lobule, portions of the concha, antihelix, and tragus are identifiable. The external auditory canal may or may not be present (Figures 2a,b). Microtia, while occasionally seen in isolation, is typically a feature of a significant underdevelopment of the facial structures derived from the first and second branchial arches. This facial hypoplasia is known as hemifacial microsomia and may vary from barely perceptible temporal bone underdevelopment to severe hypoplasia of all skeletal, neuromuscular and soft-tissue components of the face on the affected side. The deformity is occasionally seen bilaterally as part of the Goldenhar syndrome, and similar ear deformities may also be seen as part of the Treacher-Collins syndrome. In these syndromes, the position of the microtic remnant may be affected by the other skeletal and soft tissue deformities. The vestige may be found displaced anteriorly, inferiorly and medially on the cheek (a result of a combination of horizontal and vertical shortages in the facial soft tissues in combination with hypoplasia of both the temporal bone and mandible).  FIGURE 2C. In auricular dystopia, the ear deformity exists in combination with moderate to severe facial hypoplasia. In this child with Goldenhar syndrome, the dystopic vestige lies antero-inferiorly on the youngster’s cheek. (Note in addition to the dystopic auricular remnant, the small lower jaw, macrostomia and epibulbar dermoid cyst at the corner of the right eye). This condition is known as auricular dystopia (Figure 2c) and is different from the other forms of microtia in which the ear remnant is in a relatively normal position. As is discussed later, this distinction is an important one because it adds additional complicating factors to the ear construction. Timing of Evaluation and Reconstruction Given the importance of the external ear as part of the "normal" appearance of a child, it is not surprising that the parents of a child with a severe deformity of the external ear are very anxious and concerned about its effect on their child, what can be done to correct it, and how soon the child’s ear can be made "normal." Furthermore, because external deformities are typically associated with abnormalities of the middle ear, the child’s concurrent hearing loss may present an even greater concern for the parents. This is particularly true when children have bilateral involvement. Suffice it to say that all these concerns warrant early consultation with the reconstructive and the otologic surgeons because both of them have a role in explaining the varied aspects of the deformity and in helping to allay the family’s concerns, even though surgical intervention on the external ear will not be done for some years. Several factors enter into the decision about the timing of the reconstruction. These include growth of the normal ear, growth of the chest cartilage used as the donor tissue to construct the ear framework and the psychological effects of the deformity on the developing child. It has been well established that the external ear reaches near-adult size and proportions relatively early in the overall scheme of facial growth and development. By five years of age, the child’s normal ear has reached more than 85% of its adult size, and at that point it can be used as a frame of reference for constructing the affected side. While opinions vary regarding the age at which the costal cartilage is large enough to have sufficient cartilage for the reconstruction, I have found that with the technique described here (one that has been used at Children’s Memorial Hospital during the past 15 years), the repair can begin at age five. (Interestingly the repaired ear does appear to grow after surgery, and in general it comes fairly close to matching the final size of the normal side). Perhaps the best reason for proceeding at age five versus waiting until age seven or eight or later is that children begin to compare themselves with other children and are more aware of their peers’ comments at about age five. If the staged construction begins at this age, most, if not all, of the repair can be finished before the child is unduly stigmatized. Ideally, even though the initial surgery is not performed until age five, the child with microtia should be evaluated by both the reconstructive and otologic surgeons in infancy. The otologic surgeon then follows the child as closely as needed until it is established that the child’s hearing is adequate and that hearing in the unaffected ear is not compromised. The reconstructive surgeon follows the child yearly. These visits provide opportunities for the surgeon to review the complex stages of reconstruction that will come all too soon, to answer the frequent questions that arise from parents, and to establish a good relationship with the parents and the child. Surgical Repair of Lobular and Conchal Microtia Although the reconstruction of these two more typical forms of the deformity vary to some extent because of the differing parts of the normal ear that are present, the overall sequence of stages is similar and for the purpose of this brief overview, I will discuss them together. However, in auricular dystopia the skeletal and soft tissue deformities are more severe and affect the position of the microtic remnant; consequently, some of the techniques used in its repair need to be varied significantly. These differences will be touched on briefly later. Many surgeons, including Drs. Tanzer and Brent, have contributed to what is now considered "state of the art" in the reconstruction of the external ear. More recently, Dr. Nagata has taken microtia repair to an even higher level. Much more can still be done, of course, especially in light of the fact that these reconstructions are among the most difficult faced by plastic and reconstructive surgeons. The techniques mentioned in this article have been built on work of the former two; many individual modifications have been further refined with the added knowledge brought recently by the latter. In each of the approaches the basic elements are the same, though the timing and staging may differ. Each reconstruction involves three main elements and usually three stages (though this may vary from two to four). These elements are:
First Stage The first stage involves creation of the cartilage framework over which the skin of the microtic remnant and the adjacent skin is draped. It is the most complex of the stages and in the current approach creates the greater portion of the future ear. The first step is to create an x-ray film template of the child’s normal ear that shows the relationship of the ear to the other facial features (nasal dorsum, alar base, lateral canthus and lateral brow). An additional template is made of the cartilage framework construction showing the form of the helical rim, antihelix, crura and tragus.  FIGURE 3. The costal cartilage graft is carved from the contralateral 6th, 7th and 8th costal cartilages spliced together to create the three-dimensional framework that gives the reconstructed ear its shape, detail and projection. The cartilage graft is harvested from the contralateral sixth, seventh and tip of the eighth costal cartilages. The block is carved and spliced together, following the x-ray pattern, using fine stainless steel wire and nylon sutures to hold the segments together. The result is a three-dimensional form with the basic details, size and projection of the normal ear (Figure 3). Using the pattern from the normal side, the position for the symmetrical reconstruction is marked in relation to the auricular remnant. The incision is planned to allow rotation of the lobular portion of the remnant into a position that permits splicing it near its ideal position along the helical rim. Through the incision, the entire amorphous cartilage remnant in lobular microtia (or the non-useable portion of the cartilage remnant in conchal microtia) is excised, and a pocket is created under the skin flap for placement of the framework (Figures 4a,b).  FIGURES 4A, 4B. The repair of the lobular microtia shown here entails the placement of the cartilage framework with partial lobule rotation. In the preoperative view, left, notice the vestige and a small non-useable preauricular tag. Right are two views immediately upon completion of the first stage with the suction drain just visible inferior to the ear providing the vacuum that draws the skin into the folds of the framework. The cartilage framework is placed, the lobule inset and the skin draped over the folds of the graft; a suction drain creates a vacuum beneath the skin following completion of the closure. Usually the procedure lasts from three to three-and-one-half hours. The ear is protected with a cup-like bandage for seven to ten days following reconstruction, and the child goes home after one or two nights in the hospital. Second Stage At this point, the partially constructed ear has its three-dimensional form, part of its projection and its basic parts (including in some cases the tragus), but there is not as yet enough skin to drape over the back of the ear, and the lobule is, in general, not fully inset in its final position. After three to four months of healing (the typical period between each stage), the second stage is performed. In this stage, the ear is elevated off the side of the head, the lobule inset in its final position and the post-auricular sulcus created.  FIGURE 4C. A close-up view demonstrates the result following elevation of the helical rim, reconstruction of the tragus and deepening of the concha. The sulcus is formed as the ear is elevated off the mastoid surface. Part of the elevated skin drapes over the rim of the helix, and the remaining part of the sulcus is covered with a full-thickness skin graft harvested from the groin area (Figure 4c). On occasion, additional cartilage may be added to gain further projection of the ear. This may be harvested from the lower tip of the framework as the lobule is inset, or it may be taken through the previous donor scar on the chest. This procedure usually takes about half the time of the first, and the hospital stay is under 23 hours. Third Stage In this stage, the conchal depression and tragal projection are further defined. The cartilage projection in the tragal position and a shadowed hollow suggest that a canal—the pseudomeatus—is present. The tragus is either created now in the initial framework construction—in which case the conchal hollow may be further defined by excision and grafting into the depression—or the tragus is formed from a composite graft of skin and cartilage from the concha of the opposite ear along with a small skin graft from the postauricular surface of that ear (Figure 5).  FIGURE 5. [Left] The pre-operative view of a small, conchal remnant microtia. [Center] Post-operative view. In this case the tragus was reconstructed using a composite graft in the second stage and the helical rim elevated in the third stage. [Right] This wider-angle view of the same child demonstrates how a shadow is cast by the tragus suggesting the presence of the meatus. By harvesting these grafts, the surgeon has the added benefit of adjusting the projection of the opposite ear so the two sides will be symmetrical. This procedure takes about as long as the second stage and usually involves an outpatient stay only. Additional Comments on the Staged Reconstruction The procedures described vary depending on the useable portions of the remnant. When the remnant is large and relatively well formed as in conchal remnant microtia, the procedures are sometimes simpler; in some cases, the repair can be completed in two stages. Sometimes there are minor details of form, scar position or conchal depth, for example, that may be improved with additional minor procedures after six to 12 months or more—time that allows the tissues to settle and the scars to mature. Often these procedures can be done in the office under local anesthesia. For many children (and in this day and age not always for girls), the final touch is piercing their ears. The goal, after all, is to continue refining the details until the child is comfortable with the final results and willing to let the reconstruction be seen without an obscuring hairstyle or any other covering. Repair of Auricular Dystopia As was mentioned earlier, the form and position of the microtic remnant may be significantly influenced by associated underlying skeletal and soft tissue deformities. In auricular dystopia, the remnant can be markedly malpositioned such that it lies either in the middle of the cheek or down at the mandibular angle. On occasion, a stenotic canal remnant may be displaced with it. These types of deformities are far more difficult to repair than the others, and they have not been addressed nearly as much as in the literature; to some extent, their treatment has been formulated at our own institution. The repair requires an integrated approach to all elements of the soft and hard tissue deformity, and therefore requires ear construction and craniomaxillofacial reconstructive techniques. The details of these techniques are beyond the scope in this paper, but a few brief comments can be made. In auricular dystopia the ear deformity exists in combination with moderate to severe facial hypoplasia. By transposing the template from the normal ear onto the affected side, the symmetrical position of the ear is seen to lie partly in the hairline; the remnant is anterior and inferior to the ideal position. Given these conditions, it is necessary to move the remnant initially and then in the subsequent operation when the cartilage framework is placed, cover the framework with a fascial flap and skin graft rather than with hair-bearing skin. With this approach, the framework can be positioned with symmetry to the normal side, the skeletal deficiency beneath the framework can be augmented with additional cartilage graft, and the ear construction can still be completed at an early age before definitive reconstruction of the associated deformities. These reconstructions typically involve more than three stages, but some of the final steps can be coordinated with procedures needed later to reconstruct the other skeletal and soft tissue defects seen in hemifacial microsomia. Summary The treatment of microtia entails the coordination of many of the techniques of plastic and reconstructive surgery and presents ever-evolving challenges for the reconstructive surgeon. Treatment must be coordinated with the otologic surgeon, and many of the children need follow-up by the full craniofacial team because of associated skeletal deformities, potential for hearing and speech problems, potential orthodontic concerns and, finally, associated psychological considerations. Surgical treatment of the more complex ear deformities, especially when bilateral, must not only provide optimal aesthetic results but also provide optimal hearing and limit the overall number of surgical procedures. With an improved understanding of these deformities, continuing advances in all aspects of reconstruction and a team approach to evaluation and treatment, these children and their parents can look forward to a bright future. FOR FURTHER READING 1. Tanzer RC: Microtia. Clin Plast Surg 1978;6:317–336. 2. Brent B: The correction of microtia with autogenous cartilage grafts: I. The classic deformity. Plast Reconstr Surg 1980;66:1–12. 3. Brent B: The correction of microtia with autogenous cartilage grafts: II. Atypical and complex deformities. Plast Reconstr Surg 1980;66:13–21. 4. Bauer B: Reconstruction of Major Congenital and Acquired Auricular Deformities. In Riley WB (ed) Instructional Course, PSEF Vol 1, St. Louis:Mosby, 1988, 146–178. 5. Nagata S: A new method of total reconstruction of the auricle for microtia. Plast Reconstr Surg 1993;92:187–201. |