Updated: Feb 11, 2009
Congenital malformations of the external ear are uncommon birth defects with long-term sequelae for children and their families. The impact of such deformities on the patient can be both physical and emotional. Parents often experience feelings of guilt because they believe they have caused the deformity. School-aged children may be the object of teasing and ridicule. Hearing loss due to associated ear canal atresia can result in learning difficulties.
Auricular malformations range from anotia to mild alterations in the external form of the ear. Fortunately, knowledge of reconstructive techniques and audiological rehabilitation continues to improve and benefit patients.
The earliest reports of auricular reconstruction date back to 600 BC from passages in the Sushruta Samhita, in which the great Indian surgeon Sushruta describes ear lobe reconstruction using local skin flaps. In the 16th century, Gaspare Tagliocozzi reported using a transfer flap from the arm to reconstruct the ear. In 1845, Dieffenbach made the next major report when he described the reconstruction of the upper part of an auricle that had been severed sharply by a sabre. Surgeons of the 19th century believed total auricular reconstruction was impossible because no source of skin or elastic cartilage was acceptable to create the auricle.
The modern age of auricular reconstruction begins in the 20th century. In 1920, Gillies first described the use of costal cartilage grafts in reconstructing the auricle. In 1930, Pierce described the principle of creating an auricular framework from cartilage grafts. Tanzer further popularized the use of autogenous rib cartilage for reconstruction. Many of the techniques he described are the foundation of microtia repair today. Brent has further refined these techniques over the last 3 decades.1 More recent innovations have also included the use of alloplastic frameworks, incorporation of temporoparietal fascial flaps, and osteointegrated implants for the anchoring of prosthetic auricles.
Today, the basic steps in microtia repair require an average of 2-4 stages and involve the use of either an alloplast or the patient's rib cartilage to serve as a framework that is implanted under the skin. Subsequent stages may involve creating a lobule, separating the reconstructed auricle from the head, and constructing a tragus.
Surgeons involved in microtia repair have long recognized the difficulty of creating a natural appearing ear. These problems are 2-fold and include the creation of a rigid, biocompatible framework and its coverage with skin. No natural substitute exists for the thin pliable auricular cartilage. Nor is skin available of similar quality and elasticity to that covering the auricle. One key to successful reconstruction is to provide sufficient relief in the helix, scaphoid fossa, and antihelix to create the illusion of thin skin overlying thin cartilage. Problems such as thick skin, hair-bearing skin, and poor quality cartilage serve to frustrate the surgeon's attempt to achieve the desired result.
Other challenges in the creation of the auricle are properly positioning the reconstructed ear in relation to the opposite ear, providing sufficient projection of the auricle from the head, creating a postauricular sulcus, and reconstructing a natural appearing lobule and tragus.
Congenital microtia occurs with a frequency of 1 per 7000 live births. The incidence of microtia varies by race, with the highest incidence in persons of Asian and Latin American descent, as well as certain Native American groups. Persons of European origin have a lower incidence, while people of African descent have the lowest incidence. Males are 3 times more commonly affected than females, and the right ear is more commonly involved by a 2:1 ratio. Bilateral defects occur in only 12% of nonsyndromic cases, as compared with 50% of syndromic cases.
In two thirds of cases, the microtia occurs as an isolated defect. Nearly 28% of microtic ears occur in association with other birth defects. Ten percent of microtia occurs as part of a well-defined syndrome. A large proportion of microtia is believed to be due to autosomal inheritance with variable expression and incomplete penetrance. Coexisting conditions that may be present include Goldenhar syndrome, branchiootorenal syndrome, branchial cleft cysts, holoprosencephaly, Treacher Collins syndrome, and Robinow syndrome. Other malformations may include mandibular deformities, facial paralysis, and maldevelopment of the facial and cranial bones.
Rarely can an environmental or genetic cause for microtia be found. Isotretinoin and thalidomide are teratogens that can cause microtia. Microtia also can occur as a result of fetal alcohol syndrome or maternal diabetes embryopathy. Single gene disorders such as Treacher Collins syndrome or chromosomal abnormalities such as trisomy 18 also can result in microtia or anotia.
The development of the auricle involves many embryonic stages. Any small change in any of these stages may result in various forms of deformity. Some of these deformities are known variously as lop ear, cup ear (constricted ear), or cryptotia. These entities differ from microtia and are not discussed. A relationship between the severity of malformations and the amount of the auricular deformity has been noted. In general, the more auricular tissue present, the less severe the associated malformations. The precise pathophysiologic mechanisms by which teratogenic or genetic influences result in microtia have yet to be defined.
Microtia is a congenital disorder and is immediately recognizable at birth. The malformed ear may be completely absent (grade 4 microtia or anotia; see Image 1), but, most commonly, a residual malpositioned lobule is present beneath a rudimentary hillock of cartilage (grade 3 microtia; see Image 2). Microtia is usually associated with aural atresia in the higher stages. Grade 1 microtia (a small ear with normal architecture; see Image 3) often has an associated patent ear canal. Grade 2 microtia (a small ear missing much of the architectural features of a pinna; see Image 4) may or may not have a patent canal or tympanic membrane.
Ear reconstruction is indicated when a child with microtia has reached sufficient age, which may be between 3 and 6 years old. The latter age is typically recommended for rib cartilage reconstruction because sufficient time must be allowed for the normal ear to reach most of its adult size and act as an accurate template for the ear to be reconstructed. In addition, the costal cartilage will achieve sufficient size to provide adequate donor material for the framework.
Placing the reconstructed ear in the proper location is important. This placement is best determined by taking measurements from facial landmarks (ie, lateral canthus, alar facial crease, lateral commissure) to the normal ear and transposing the same measurements to the side of the deformity. Making a template of the normal ear from overexposed radiographs ensures that the reconstructed ear has the appropriate size and shape.
In many children, the hairline on the abnormal side is unusually low, causing the cartilage framework implant to be placed at least partially under hair-bearing scalp. Recognizing this problem at the outset is better than attempting to shift the framework inferiorly and anteriorly. The problem of hair over the ear can be addressed later using electrolysis, skin grafting, or laser hair removal.
In patients with hemifacial microsomia, measurements from the normal side of the face would cause the surgeon to place the auricular framework far posterior to the auricular remnant. This eventuality would prevent the surgeon from using the malformed hillocks in lobule reconstruction. In these cases, addressing the hemifacial microsomia first is best, so that mandibular symmetry may be achieved. With this accomplished, proper positioning of the auricle is more likely to result.
Typically, the otologist performs hearing restoration surgery after the first stages of microtia repair are complete. The temporomandibular joint, the path of the facial nerve, and the location of the temporal fossa dura are landmarks that dictate the position of the new ear canal.
Occasionally, in persons with microtia and aural atresia, the pinna is not centered over the ideal location for canal placement. In these individuals, the auricular framework can be shifted a few millimeters in the appropriate direction or the conchal bowl may be enlarged. By the time auricular reconstruction is initiated, ossification of the mastoid bone is complete and the facial nerve, deep to the planes critical to microtia repair, should be protected. Nevertheless, overzealous use of the electrocautery may transmit damaging current to the nerve, particularly in smaller children. In patients with multiple facial anomalies in whom the course of the facial nerve is in question, nerve monitoring should be considered.
Skin quality is another anatomic factor critical to a good outcome. Dissection of the pocket for the auricular framework must be carried out in the subcutaneous plane, deep to the subdermal vascular plexus, but superficial to the galea and other elements of the superficial musculoaponeurotic system complex (SMAS) plane. This allows the skin to be stretched and conformed to the underlying framework. Any prior damage to the skin in this area makes the task of reconstruction significantly more difficult. Radiation therapy, actinic damage, cigarette smoking, and trauma have the potential to rob the skin of critical blood supply, deprive it of healing characteristics, and prevent it from adequately revealing the intricacies of the cartilage framework.
If rib cartilage is to be used, the donor cartilage must be of the appropriate size before reconstruction can be contemplated (see Preoperative details). Adequate cartilage size is generally achieved by the time the child is aged 6 years. This is when the surgeon may harvest the cartilaginous portions of the contralateral sixth, seventh, and eighth ribs to form the framework. To ensure that the cartilage remains viable and has the potential for future growth, perichondrium must be preserved over the harvested portions. In taking pains to preserve the deep perichondrium, the surgeon often violates the parietal pleura. This problem is addressed during surgery by evacuating any air from the pleural cavity with a Valsalva breath, sealing the opening with a running watertight closure, and placing a temporary suction drain in the chest.
Auricular reconstruction using costal cartilage probably is not indicated for patients with limiting anomalies in other parts of the body. Other contraindications include lack of graft material in patients with previous cartilage harvest, patients with poor skin quality in the auricular area secondary to burns or previous surgery, and patients who are poor anesthetic risks.
Unless indicated by the patient's overall medical condition, no particular laboratory studies are obtained routinely.
Aural atresia repair requires a fine cut noncontrast axial and coronal CT scan of the temporal bones. The timing of this study is not critical and may be deferred until the otologic procedure is anticipated.
For microtia repair, no routine diagnostic procedures are necessary, unless a thorough history and physical examination reveal that particular studies are necessary.
Because microtia consists of malformed cartilages and skin appendages, no routine histologic examination is indicated. In fact, no pathologic specimen is obtained under normal circumstances.
Meurmann staged microtia as follows:
Grade 3 is the abnormality most commonly encountered in patients desiring reconstruction. Note that anotia is not considered under the above classification.
Nonsurgical treatment of microtia is primarily with prosthetic replacement. This method of treatment has the advantage of providing an ear with a very natural appearance and should be offered to the patient or their parents as an alternative to surgical reconstruction. Prosthetic replacement may be the best alternative in a person with complete anotia because reconstruction of the lobule is a challenging task and is often met with less than optimal results.
Disadvantages of prosthetic reconstruction include the fact that it must be attached to the side of the head. Adhesives may be used, but these have limited strength. Osseointegrated implants to the temporal bone may be joined to a metal framework, which is then connected to the prosthesis by means of magnets. This is a somewhat more secure option than adhesives but is not without problems. The prosthesis is expensive and also wears out, needing frequent replacement. The prosthetic has a tendency to fade when exposed to sunlight or seawater. Obviously, a prosthetic is insensate and feels like an unnatural appendage or ornament rather than part of a patient's own body. The potential also exists for social embarrassment if the prosthesis becomes unglued or detached in public.
The mainstay of surgical therapy for microtia reconstruction has been costal cartilage rib grafting. This is typically a 3-4 stage procedure, whereby the ear is created from local tissue flaps and a cartilage framework carved from rib cartilage.
The first stage involves the carving of rib cartilage into the shape of an external ear and placing the graft into a pocket created in the skin overlying the temporal bone. In the second stage, a Z-plasty is performed, which rotates the auricular remnant inferiorly, creating a lobule. The third stage elevates the cartilage graft off the temporal bone, creating a postauricular sulcus with a split-thickness skin graft. These 3 stages are spaced at 6-month intervals to allow for reestablishment of blood supply between procedures. A fourth stage may be added later to create a neotragus.
Another option with microtia reconstruction is the use of porous polyethylene (Medpor) as the framework (see Image 5). Proponents for the use of this alloplastic option cite the ability to start the reconstruction at an earlier age, as young as age 3. This is possible because one does not need to wait for rib cartilage to achieve appropriate size. Another advantage is avoiding the pain and potential deformity of the rib donor site. The reconstruction may be completed in 2 stages, as opposed to 4 with the rib option.
The final cosmetic result may be superior with alloplasts because framework projection is easier to achieve, the need to sculpt is limited, and the alloplast does not resorb. On the other hand, a danger of extrusion or infection exists with alloplast that is only rarely seen with cartilage. The first stage of alloplastic reconstruction generally takes longer to perform but is associated with a shorter hospital stay. Shaving half the head is necessary, in order to make a long transverse incision to lift a temporoparietal flap. This may result in areas of temporary or permanent alopecia.
As with reconstruction using cartilage, a template from the normal ear is used. The auricular framework is constructed from 2 components, which are trimmed to fit the template. The 2 components are welded together using a thermal cautery or are sutured together with permanent suture. The temporoparietal flap covers the alloplast, and a full thickness skin graft is placed on the flap. The second stage consists of lobule transposition, very similar to the second stage performed with rib cartilage. A third and fourth stage, as needed with the rib cartilage technique, are generally not needed with the alloplast option.
In the authors’ practice, families are presented with both options and are allowed to decide which option they prefer based on their understanding of the risks and benefits. In cases of implant exposure, repair with a local flap is possible if the defect is less than one centimeter squared. For larger exposures, explantation is recommended, followed by revision surgery one year later using rib cartilage.
Timing of reconstruction using rib is based on 2 primary factors. First, a sufficient amount of costal cartilage must exist, specifically the synchondrosis of the fifth through seventh ribs. Second, in unilateral microtia repairs, the normal ear must be at least 85% of normal adult size. Typically, sufficient size is achieved in most children by the time they are aged 5-6 years.
If the alloplastic option is considered, the patient should be evaluated for a palpable superficial temporal pulse, in order to predict adequate blood supply to the temporoparietal flap. Patients as young as age 3 may be considered for this option, and slight overcorrection of the framework should be carried out in younger patients to allow for future ear growth on the normal side.
Rib Option
Alloplast Option
Rib Option
Patients are seen preoperatively, at 1 week postoperatively, and as needed thereafter.
Rib Option
The most frightening common complication with the rib cartilage microtia repair is skin loss. For this reason, the surgeon is doubly careful to avoid damaging the subdermal plexus or stretching the skin unduly. The field is never injected with epinephrine-containing solutions so that blanching of the skin may be monitored accurately. Fortunately, when skin loss occurs, it is usually limited in scope and can be managed adequately with the excision of small portions of exposed cartilage and aggressive wound care. These areas usually heal by secondary intent.
Occasionally, portions of the skin graft are lost. If the underlying perichondrium is still intact, a new graft may be placed successfully. For larger areas of skin loss, a local flap procedure needs to be performed. The temporoparietal flap is a good choice because it is thin, pliable, and in close proximity. After turning down the flap and covering the exposed cartilage, the flap is grafted onto skin. Although the grafted skin has a poor match of color, texture, and thickness, these differences tend to minimize with time.
Resorption of the cartilage graft may occur if the cartilage is denuded of perichondrium during the harvesting stage or during the formation of the framework.
Dislocation of the cartilage elements of the framework may occur, especially if the helix is not secured adequately onto the cartilage base. For this reason, multiple permanent sutures are used. Because wire has a tendency to extrude or become infected, it no longer is used. Despite the possibility of suture failure, the potential for cartilage dislocation is small because the graft has been secured within a precise confined pocket of skin.
Keloid and hypertrophic scar formation are problematic because they defy any satisfactory correction and are difficult to predict. Although surgical resection of the scarred tissue may be attempted, the results are likely to be disappointing. Local injection of long-acting steroid compounds may be attempted.
Infection may occur despite meticulous sterile technique and perioperative antibiotic therapy. Most infections are small and well localized. In some cases, local wound care and a week-long course of oral antibiotics may be necessary. Occasionally, a retained suture needs to be removed.
Alloplast option
Exposure and infection of the framework are more worrisome complications for reconstructions using an alloplast than those using rib cartilage. Plastic implants may develop colonization with bacterial biofilms upon exposure, and the ensuing infections may be difficult, if not impossible, to treat without explantation of the framework. These exposures are more problematic in the initial postoperative period, when vascular integration of the porous implant has not been completed. Smaller (< 1 cm), late-term exposures may be successfully closed with local advancement rotation flaps. Otherwise, the implant is removed and reconstruction using rib cartilage is attempted at a later date, giving the soft tissues time to regain some pliability and a healthy blood supply.
Under ideal conditions, a surgeon with some degree of artistic ability who uses sound judgment can expect a good result after adequately spaced stages. Nevertheless, much of the prognosis depends on factors beyond the surgeon's immediate control, such as skin pliability, scar tissue formation, and the resolution of edema.
The greatest morbidity with the rib cartilage technique is at the harvest site. The postoperative pain, the thoracic scar, and the occasional concavity produced in the chest area have motivated surgeons to seek an adequate alternative. The use of porous alloplastic material has proven to be effective, but concerns persist about its long-term viability and the propensity for exposure and infection.
Prosthetic ears, with or without osteointegrated fixation, are popular with some physicians. Although these prosthetics are remarkably natural in appearance, they have several drawbacks. These include limited longevity, lack of sensation, and unnatural feel. Prosthetics should probably not be considered a first-line remedy for microtia.
Cadaveric (homograft) or animal (xenograft) cartilage has been demonstrated to have high resorption rates that make them unacceptable for preserving the delicate architecture of the reconstructed ear. In addition, concern exists about the transmission of HIV or slow viral diseases.
Seeding autologous cartilage onto a biologic framework to grow tissue in a foreign host is now possible. An auricular cartilage framework was grown in a nude mouse, whose picture was circulated widely by the lay press. Nevertheless, problems remain with such technologies, primarily because the new cartilage lacks the skeletal strength to withstand the contracting forces of the skin pocket and the subsequent scar formation.
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ear reconstruction, ear, ear deformity, microtia, anotia, external ear deformity, aural atresia, external ear reconstruction, microtia repair, auricular reconstruction
Joseph L Leach Jr, MD, Associate Professor of Otolaryngology, University of Texas Southwestern Medical School
Joseph L Leach Jr, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Cosmetic Surgery, American Academy of Facial Plastic and Reconstructive Surgery, American Academy of Otolaryngology-Head and Neck Surgery, Texas Medical Association, and Triological Society
Disclosure: Nothing to disclose.
Michael J Biavati, MD, Clinical Assistant Professor of Otolaryngology, University of Texas Southwestern; Private Practice, ENT Care for Kids, Dallas, TX
Michael J Biavati, MD is a member of the following medical societies: American Academy of Otolaryngology-Head and Neck Surgery, American Academy of Pediatrics, American Cleft Palate/Craniofacial Association, American College of Surgeons, American Laryngological Rhinological and Otological Society, American Society of Pediatric Otolaryngology, Society for Ear, Nose and Throat Advances in Children, and Texas Medical Association
Disclosure: Nothing to disclose.
John C Li, MD, Private Practice in Otology and Neurotology; Medical Director, Balance Center
John C Li, MD is a member of the following medical societies: American Academy of Otolaryngology-Head and Neck Surgery, American College of Surgeons, American Medical Association, American Neurotology Society, American Tinnitus Association, Florida Medical Association, and North American Skull Base Society
Disclosure: Nothing to disclose.
Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment
Dominique Dorion, MD, MSc, FRCSC, Program Director and Division Chair, Professor of Surgery, Division of Otolaryngology, University of Sherbrooke, Canada
Disclosure: Nothing to disclose.
Christopher L Slack, MD, Otolaryngology-Facial Plastic Surgery, Private Practice, Associated Coastal ENT; Medical Director, Treasure Coast Sleep Disorders
Christopher L Slack, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Facial Plastic and Reconstructive Surgery, American Academy of Otolaryngology-Head and Neck Surgery, and American Medical Association
Disclosure: Nothing to disclose.
Arlen D Meyers, MD, MBA, Professor, Department of Otolaryngology-Head and Neck Surgery, University of Colorado School of Medicine
Arlen D Meyers, MD, MBA is a member of the following medical societies: American Academy of Facial Plastic and Reconstructive Surgery, American Academy of Otolaryngology-Head and Neck Surgery, and American Head and Neck Society
Disclosure: Covidien Corp Consulting fee Consulting; US Tobacco Corporation unstricted gift unknown; Axis Three Corporation Ownership interest Consulting; Omni Biosciences Ownership interest Consulting; Sentegra Ownership interest Board membership; Syndicom Ownership interest Consulting; Oxlo Consulting; Medvoy Ownership interest Management position
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