------------------------------------------------------------------------------- TITLE: Surgical Procedures of the External Ear Canal and Ear SOURCE: Dept. of Otolaryngology, UTMB, Grand Rounds DATE: May 5, 1993 RESIDENT PHYSICIAN: Kathleen McDonald M.D. FACULTY: Jeff Vrabec M.D. DATABASE ADMINISTRATOR: Melinda McCracken, M.S. ------------------------------------------------------------------------------- "This material was prepared by resident physicians in partial fulfillment of educational requirements established for the Postgraduate Training Program of the UTMB Department of Otolaryngology/Head and Neck Surgery and was not intended for clinical use in its present form. It was prepared for the purpose of stimulating group discussion in a conference setting. No warranties, either express or implied, are made with respect to its accuracy, completeness, or timeliness. The material does not necessarily reflect the current or past opinions of members of the UTMB faculty and should not be used for purposes of diagnosis or treatment without consulting appropriate literature sources and informed professional opinion." History Ear reconstruction was first referred to in the Susruta Samhita in India (1907), in which the use of a cheek flap was suggested for the repair of the earlobe. As early as 1597, Tagliacozzi described repair of both upper and lower ear deformities with retroauricular flaps. In 1845 Dieffenbach reported the repair of the middle third of the ear with an advancement flap. Early surgery primarily focused on traumatic deformities, but by the end of the 19th century surgeons began to address the congenital auricular deformity of prominent ears. The concept of microtia repair began in 1920 by Gillies when he buried carved costal cartilage under mastoid skin and subsequently separated it from the head with a cervical flap. Pierce in 1930 modified this method by lining the new sulcus with a skin graft and building the helix with a tubed flap. Gilles (1937) repaired auricles with maternal cartilage which was found to be resorbed so it was discontinued. Many have tried to use allograft material and synthetic material and have had discouraging results with high extrusion rates. A major breakthrough came in 1959, when Tanzer rekindled the use of autogenous rib cartilage, which he carved in a solid block. To this date, autogenous cartilage remains the most reliable material that produces results with the least complications. Anatomy The ear is difficult to reproduce surgically because it is made up of a complexly convoluted frame of delicate elastic cartilage surrounded by a thin skin envelope. The denuded cartilage framework conforms almost exactly to the ear's surface contours except for its absence in the earlobe, which consists of fibrofatty tissue rather than cartilage. In most microtic vestiges, the presence of the lobular tissue is a valuable assets in the repair. When the lobule is lost in total ear avulsions, it is best recreated by shaping the bottom of the carved ear framework to resemble the lobe. The ear's rich vascular supply come from the superficial temporal and posterior auricular vessels, which can nourish a nearly avulsed ear even on surprisingly narrow tissue pedicle. The sensory supply is chiefly derived from the inferior coursing great auricular nerve. The upper portions of the ear is supplied by the lesser occipital and auriculotemporal nerves, whereas the conchal region is supplied by a auricular branch of the vagus. At three years of age, 85% of its auricular growth has been achieved. Ear width and distance from the scalp will change only minimally after age 10. Contrary to cartilaginous growth of the nose, that of the auricular cartilage is nearly completed at age 5 or 6. This permits corrective surgery before the child starts school. Normal ears are often asymmetrical in their position and size and degree of protrusion. The auriculocephalic angle is between 25 - 35 degrees (40 to 45 degrees is considered abnormal). The vertical height is usually equal to the distance between the lateral orbital rim and the root of the helix (6 cm). It also the vertical axis should incline about 20 degrees posteriorly. The width is approximately 55% of the length, with the superior aspect even with the brow. Embryology: The otic placode is first evident at 3 weeks. Then at 6 weeks the auricular hillocks of His are present. Theses are responsible for the development of the auricle. The three cranial hillocks belong to the mandibular (1st branchial) arch and the three caudal hillocks belong to the hyoid (2nd branchial) arch. The first three form the tragus, crus helicis and the helix. The second three form the antihelix, antitragus and the lobule. During the 8th and 12th weeks of gestation, the skin and helix grow rapidly overlying the underdeveloped antihelix. The anti helix unfurls during the 12th and 16th weeks. If this fails to occur, an overhanging or protruding ear is left. Microtia represents the arrest in development in the 6th to 8th week of gestation. Auricular deformities can be classified as either acquired or congenital. The acquired deformities are related to trauma or excisions for neoplasms. There are numerous congenital auricular deformities. They range from complete unilateral/bilateral anotia to subtle alterations in the external configuration. Congenital auricular deformities are a manifestation of developmental problems of the first and second branchial arches, and often other arch deformities are present, such as hypoplasia of the mandible, maxilla, and soft tissue on the side of the face of the atresia. The most common deformity of congenitally microtic auricle is a longitudinal fold of skin (peanut ear) that contains a markedly disfigured auricular cartilaginous remnant that is usually anatomically located in the position of what one might anticipate as the external auditory canal. Etiology Microtia occurs 1 in every 6000 births. The occurrence is estimated to be 1 in 4000 for Japanese and as high as one in 900 to 1200 in Javajo Indian. Microtia is nearly twice as likely in male as in females, and the right-to-left-to-bilateral ratio is 5:3:1. Congenital abnormalities of the Auricle show a transmission pattern of mendelian dominance with variable penetrance. The severity of the abnormality appears to be in degrees of penetrance. Ear deformities frequently occur in families of patients with mandibulofacial dysostosis (Treacher Collins syndrome). Many patients with microtia have evidence of the first and second branchial arch syndrome (craniofacial microsomia). In previous studies it is thought that this is multifactorial and there is approximately a 6 % risk of recurrence in first degree relatives. Classification: There has been many different classification schemes to describe the congenital malformations of the auricle. Marx, in 1926, used four major grades of microtia. This was amended by Jahrsdoerfer and Aguilar in 1988. Grade I is a normal ear. Grade II has some of the auricular framework present, but there are obvious deformities. Grade III is the standard "peanut ear" deformity, which encompasses anotia (Marx's grade IV). In 1977 Tanzer proposed a clinical classification of auricular defects which is often used in publications since that time. He classified the congenital ear defects according to the approach necessary for their surgical correction. I. Anotia II. Complete hypoplasia (microtia) A. With atresia of external auditory canal B. Without atresia of external auditory canal III. Hypoplasia of middle third of auricle IV. Hypoplasia of superior third of auricle A. Constricted (cup or lop) ear B. Cryptotia C. Hypoplasia of entire superior third V. Prominent ear Complete Microtia Clinical Microtia varies from the complete absence of auricular tissues (anotia) to a somewhat normal but small ear with an atretic canal. The most common abnormality lies between these and is a sausagelike ("peanut ear") remnant oriented vertically. The lobule is usually displaced superiorly to the level of the opposite normal side. Incomplete migration can leave it inferior. Nearly half of the patients exhibit gross characteristics of unilateral craniofacial microsomia. Goals of auricular reconstruction The rehabilitation of the congenital or acquired auricular deformity requires a multistaged surgical reconstruction or the use of a prosthesis. The surgical goal or prosthetic auricular rehabilitation are the same: both are being undertaken to help restore facial symmetry. This means to create a structure that has a comparable size to the normal auricle in the unilateral case or a comparable size to a reconstructed auricle in bilateral microtia with atresia and is also located in a similar position and at a similar distance away from the side of the head. Surgical Auricular Reconstruction: The reconstruction of the auricle usually takes 5 stages (up to 13). The principles here can be used to reconstruct a congenital microtia or an acquired defect. There are five primary operations involved with total auricular reconstruction. The first involves the use of existing tissue to form a portion of the reconstructed auricle. That operation is followed by another that is intended to insert a rigid framework of the reconstructed auricle. The third operation involves the transfer of tissue that will ultimately be used to create the medial epithelial surface of the reconstructed auricle. The final operation involves the transferring of the reconstructed auricle into the normal auricular position. After the four primary procedures have been completed, it is not unusual to require additional lesser "touch up" procedures to attempt to improve minor deformities. Stage 1 Most adult auricular growth had been achieved by the time a child reaches 7 years of age. This is the time the reconstruction will begin. The first step is to develop a template using sterile x-ray film in the configuration of a normal auricle (opposite if unilateral.) The template is then used to draw the planned auricle with methylene blue in the optimal anatomical position. Z-plasty or an inferiorly based pedicle flap can be used to reposition the lower 1/3 part of the vertical fold of skin to form the lobule. The underlying deformed cartilage is removed taking care to dissect close to the skin as to avoid damage to the usually malpositioned facial nerve. Stage 2 The second operation occurs after healing is complete and the surgical scars have softened and become pale. This step involves the insertion of a rigid auricular framework. This will be used to contour the helix and antihelix and aid in the correct positioning of the newly formed lobule. A variety of autologous and synthetic materials have been used in the past to provide this rigid support. Although there is minimal donor site morbidity with this there are frequent problems with wound breakdown, extrusion, and infection. The harvest of the autologous costal cartilage is obtained en bloc from the side contralateral to the ear being constructed, so as to utilize the natural rib configuration. The cartilage is removed through a slightly oblique incision just above the costal margin. The helical rim is fashioned separately using cartilage from the first free-floating rib. Excision of this cartilage facilitates access to the synchondrotic region of the sixth and seventh ribs, which supplies a sufficient block to carve the framework body. Care must be taken not to enter the pleural space and cause a pneumothorax which may require a small chest tube. Autologous costal cartilage fashioned in three curved arches which are carved into the shape of the helix/antihelix complex. The framework exaggerates the helical rim and the details of the antihelical complex. The contour is refined using a mastoid burr. Satisfactory long term results ultimately depends on living tissue so some authors prefer to avoid power tools which could damage the chondrocytes. The cartilage is sculpted and thinned to cause deliberate warping in a favorable direction. This allows one to produce the acute flexion necessary to create a helix, which is fastened to the framework body with horizontal mattress sutures. A cutaneous pocket is created and the framework is then buried in a superficial subcutaneous pocket. Care must be taken to preserve the subdermal vascular plexus of the thin skin. Suction drainage is used to coapt the skin flap and prevent hematoma formation. Firm pressure dressing is dangerous and unnecessary. Stage 3 The third operation is the repair of the atresia by the otologist. As the human ear's inner portion is derived from embryologic tissue different from that of the conductive portion, the inner ear is rarely involved in microtia and these patients should have serviceable hearing. The problem is conductive, which is blocked by the malformation of the middle and external ear complex. Typically these patients have 40 % of the hearing on the affected side. Because of the normal inner ear patients with bilateral microtia usually have serviceable hearing, and bone conductive hearing aids should be used. Surgical correction of the conductive problem is difficult because the middle ear lying beneath the closed skin is not normal. Exploration involves cautiously avoiding the facial nerve while drilling a canal through solid bone. One must create a tympanic membrane with a tissue graft; the distorted or fused ossicles may be irreparable. The skin grafts are not readily vascularized on the drilled bony canal, chronic drainage is frequently complication and meatal stenosis is common. It is believed that middle ear surgery should be reserved for bilateral microtia. The auricular reconstruction should precede the middle ear surgery, since once the skin is scared a good auricular reconstruction is difficult. This should be done after the first two stages of repair. The temporal bone remnant is in only one location, and thus the opening to the remnant can be made in only one location on the overlying skin. Therefore, it is quite easy to manipulate the framework and line it up where the otologist has drilled the canal. Stage 4 The tragus is constructed using the composite cartilage taken from the contralateral ear and A J shaped incision is made in the concha. Stage 5 The fifth operation is for the elevation of the auricle. The postauricular skin flap is incised and elevated to cover the medial aspect of the newly formed auricle. A split thickness or full thickness skin graft is used to cover the created postauricular defect. Some authors take an additional step and create a postauricular skin tubular graft and then stage to reconstruct the helical rim and medial aspect of the auricle Complications: Complications are possible during the surgical reconstruction. The placement of the cartilage graft places severe strain on the overlying skin, which can cause skin necrosis. Infection can result in reabsorption of cartilage, and there may be improper placement of the framework. Any grafting procedure can involve graft loss. Keloid formation is possible. Constricted Ear This is considered any ear anomaly in which the encircling helix seems tight, as if constricted by a purse string. These have been termed "cup" or "lop" ears, these deformities collectively have helical and scaphal hooding and varying degrees of flattening of the antihelical complexes. Lop-ear deformity Congenital deformity that is often familial. During the third month of gestation, the protrusion of the auricle increases; by the end of the sixth month the helical margin curls, the antihelix forms its fold, and the anthelical crura appears. Anything that interferes with this process will result in a prominent ear. The basic deformity is the lack of development of the antihelix with the resultant protrusion of the auricle. This deformity has no negative impact on the patient's hearing, yet has a profound psychological impact. Accordingly it is advisable to recommend surgical correction before the begins school which would be around 5 years of age. The literature describes several techniques for the correction of lop-eared deformity. These techniques often incorporated a step that involves cutting the auricular cartilage with the creation of an abnormally sharp bend in the position of the anthelix. However, Mustarde (1963) described the technique that primarily involves suturing the auricular cartilage with horizontal mattress sutures that create a gently and more normal- appearing antihelical fold. The Mustarde approach has been the basis for most currently used surgical reconstructions of the lop-eared deformity. During the surgery a clear drape must be used to compare ears and also have visual access to the rest of the facial landmarks so that the surgeon can determine the ideal auricular contour and position during the procedure. The outline of the antihelix is placed on the lateral aspect of the auricle. A postauricular incision is made and the skin is elevated of the cartilage. A needle directed from the lateral surface perforates the auricular cartilage, an then the tip is touched with methylene blue so that it stains the tissue as the needle is retracted. This is done in several places along the new anthelix. Horizontal mattress sutures are then placed using 5-0 clear nylon that transverse the entire thickness of the cartilage including the perichondrium on the lateral surface. Reprotrusion of the corrected lop-ear deformity is the most common complication of suture otoplasty. This can be minimized by assuring that the sutures have passed thought all auricular cartilage layers. All the sutures (5-6) are place before tightening them. The sutures are tightened down so that the superior helical rim is approximately 2 cm from the side of the head and the lobule is about 1 cm from the side of the head. The temptation is to tighten the suture excessively, which medially displaces the auricle against the side of the head. The excessive skin is then excised in a fusiform fashion, and the postauricular skin incision is closed. The skin provides no strength to the medial displacement of the auricle. Lop-eared deformity may not be only a function of the lack of an antihelix but also a deep conchal bowl. The deep conchal bowl can be modified by excising a cartilaginous ellipse form the medial aspect of the conchal bowl then placing a 5-0 clear nylon suture through the conchal cartilage to the mastoid periosteum near the external auditory meatus using a horizontal mattress suture. This will displace the conchal bowl towards the external auditory canal and decrease the depth and protrusion of the bowl. Stenosing the external meatus must be avoided. Care must be taken to avoid a telephone ear deformity resulting in overly enthusiastic correction of the middle third segment of the ear. Pinching of the external auditory meatus can occur with improper placement of conchal sutures. Cryptotia Cryptotia is the unusual congenital deformity in which the upper pole of the ear cartilage is buried beneath the scalp. The superior auriculocephalic sulcus is absent but can be demonstrated by gentle finger pressure. This is common in Japan with one in 400 births. The nonoperative procedure is accomplished by applying an external conforming splint. This is successful if done in infants less than 6 months of age. Surgical repair entails using many different types of flap such as Z-plasty, V-Y advancement, or rotational flap as well as a skin graft to replace deficient skin of the retroauricular sulcus. Acquired Deformities Injuries may range from loss of skin to full-thickness loss of part of the auricle. Loss of skin with an intact perichondrium can be repaired with a split-thickness skin of full-thickness skin graft. Postauricular skin from either side provides a good color match. Skin may also be obtained from the supraclavicular areas. If the skin and perichondrium have been lost, vascularized tissue is need to cover the cartilage. A skin flap from the adjacent postauricular or preauricular area may be used. If the area of exposed cartilage is small, it is simply excised and the wound edges are reapproximated. If none of these options are available then local wound care and granulation is allowed prior to grafting. Repairs of full-thickness losses of auricular tissue, such as the helical rim or the earlobe, or major segmental defects involving the upper, middle or lower third of the auricle are more complex and may require multiple procedures. The method chosen to repair a loss of the helical rim depends on the size of the defect. A small (less than 2 cm) defect can be converted to a wedge and closed primarily, with the excision of side triangles if necessary to avoid cupping. A larger loss may require advancement of the adjacent helical rim. A chondrocutaneous flap is created from the adjacent helix, both superior and inferior to the defect. An incision is made through the skin and cartilage on the lateral surface of the auricle. The skin on the medial surface is then widely undermined, which allows advancement of the flaps to close the defect. Large defects of the helical rim can be closed using advancement techniques, the resulting decrease in ear size may be cosmetically unacceptable. If it appears that primary closure will result in a ear that is too small, the repair may be staged using additional tissue brought into the defect to reconstruct the helical rim. If it is determined that a staged procedure is necessary, the skin should be closed to provide coverage of the cartilage. This may be done by burying the edge of the remaining cartilage under the postauricular skin. This provides the necessary coverage of the cartilage, and the skin may be used in the first stage of the reconstruction. Conchal cartilage may be harvested from the ipsilateral or contralateral ear and used as a composite graft. The earlobe may be reconstructed using folded skin from the postauricular area or medial surface of the auricle. Acquired deformities of the auricle present special problems differing from microtia in the fact that many times skin coverage is deficient. Partial Auricular Loss With a small partial auricular deformity many times a conchal cartilage graft from the contralateral ear can be used. Ipsilateral cartilage can also be used but it is imperative that an intact antihelical strut be present to permit removal of cartilage without collapse of the ear. With small to moderate-sized defects a composite graft from the unaffected ear may be used. One can resect a wedge-shaped composite graft of less than 1.5 cm in width from the scapha and helix of the unaffected ear and transplant it to a clean-cut defect on the contralateral ear. Repair of the helical rim for acquired defects vary in size. This defect can be repaired by auricular skin and cartilage advancement of retroauricular skin advancement flap. Upper third defects may be reconstructed by four major methods. 1. minor loss confined to the rim are repaired by helical advancement or by readily accessible preauricular flap. 2. Intermediate losses of the upper third are repaired with a banner flap based anterosuperiorly in the auriculocephalic sulcus. This flap should be used in conjunction with a small cartilage graft for support. 3. Major losses in the superior third are most successfully reconstructed with a contralateral conchal cartilage graft. The cartilage graft is secured to the cartilaginous remnant of the helical root by sutures to insure helical continuity. 4. If the existing skin is unfavorable for the above technique, the entire concha may be rotated upward as a chondrocutaneous composite flap on a small anterior pedicle of the crus helicis. Middle third auricular defects are usually repaired with a cartilage graft, which is either covered by an adjacent skin flap or inserted via the tunnel procedure. The tunnel procedure was perfected by Converse in 1958 is effective for moderate sized defects. The auricle is pressed against the mastoid area and lines are drawn on the skin keeping them parallel to the adjacent edge of the auricular defect. Incisions are made through the skin along the line and through the edge of the auricular defect. The medial edge of the auricular incision is sutured to the anterior edge of the mastoid skin incision. A cartilaginous graft is placed in the soft tissue between and joined to the edges of the auricular cartilage defect. The mastoid skin is undermined and advanced to cover the cartilage. A healing and vascularization period of two or three months is permitted. The auricle is detached in a second stage, and the retroauricular area is covered with a skin graft. Replantation of the amputated auricle The choice of salvage procedure is influenced by the size of the amputated portion, the condition of the tissues of the amputated segment, and the condition of the stump and surrounding tissues, particularly in the retroauricular area. Clean cut amputations have a higher reimplantation rate. Small amputated segments are replaced as composite grafts with some hope of success. If the composite graft is all or a large part of the auricle aggressive medical therapy must be used in conjunction with the surgery. The patients are treated with several days of IV antibiotics and anticoagulation with heparin and dextran, and in some instances vasodilators were used. Venous congestion must be relieved; this can be done with multiple stab incisions or medicinal leeches. Due to the rich vascularity of the auricle partly avulsed auricular tissue can be successfully replace even though the remaining attachment is tenuous. Another method is the "pocket principle" were the severed part is dermabraded, and anatomically reattached to the remaining auricle. A postauricular pocket is created in which the reattached part is buried. After 2 weeks, the buried portion is brought out and allowed to reepithelialize. There has been some success with microsurgical reattachment of the amputated auricle or auricular defects. Burns Auricular trauma with resulting skin loss is usually secondary to burns. Superficial second degree burns of the skin usually heal with little if any deformity. In third degree burns, the ear skin exposes segments of underlying auricular cartilage, leading to desiccation of the cartilage and areas of focal necrosis. If not to extensive coverage of the cartilage with musculocutaneous flap can sometime prevent significant deformity. Suppurative chondritis is common with exposed cartilage which occurs three to five weeks after the burn. This is better prevented than treated with the use of topical ointments to prevent bacterial proliferation (sulfamylon). The repair of ear deformities employs the same surgical technique as with acquired deformities. Skin covering When local skin is irreparably scarred or the skin graft is inadequate to permit framework placement a temporoparietal fascial flap is used. All thick scar must be excised taking care to preserve the temporal vessels. The rib cartilage is sculpted as above and place with a covering of fascia. This secured to the peripheral skin and then covered with a skin graft. The remainder of the reconstruction takes place with stage 3 and 4. Keloids Traumatic clefts and keloids that result from ear piercing are the most common acquired defects of the ear lobe. Keloids occur especially in young blacks and Asians between the ages of ten and thirty years. Keloids may be treated with intralesional injections of triamcinolone acetonide, pressure, or surgery, or in combination. Intralesional injections of 20 to 40 mg per ml of triamcinolone combined with pressure provided by clip-on earrings will reduce to size of a keloid. These injections are repeated every three to four weeks. Keloids that do not respond to this therapy may be excised. Carbon dioxide laser excision is used to surgically remove the lesions. During the postoperative period it is important that the surgical site be injected every three to four weeks with 5 to 10 mg of triamcinolone. It appears that regular injections over an extended period of time is more important that the volume or strength of the solution that is injected. Traumatic clefts Traumatic clefts occur when earrings are accidentaly pulled out or with prolonged use of heavy earrings. These tears can usually be repaired by simple closure or by other more complex surgical procedures. A Z-plasty at the low point of the closure may prevent the earlobe from healing with an indented scar or notch. Approximately six to eight weeks later, the earlobe may be repierced. Auricular Hematoma Due to the positioning of the ear it often experiences both blunt and penetrating trauma. This occurs frequently in the contract sports such as boxing and wrestling or as we often see it in the Schooler. This glancing-type injury often results in s subperichondrial hematoma. If left untreated there may be disastrous results, most notably "cauliflower" ear. The mechanism by which cauliflower ear develops where a subperichondrial collection of serosanguinous fluid stimulates the proliferation of mesenchymal cells in the overlying perichondrium by elevating it off the cartilage. Eventually, the chondroblasts form new cartilage causing neocartilage to form in the shape of a cauliflower. The anterior auricle is tightly adherent to the underlying perichondrium; the skin of the posterior surface is more loosely attached to the perichondrium and is able to slide. This is why there is a tendency for the hematoma to form on the anterior surface. The treatment of the hematoma differs depending on the timing of presentation after the injury. It is unlikely that significant formation of neofibrocartilage appears before 7 to 10 days. If the injury is fresh the access to the hematoma is gained by incision through the anterior surface of the pinna at its most dependent point and a drain is placed. A through and through pressure dressing using dental rolls is often used. There is an increase in incidence of chondritis and infection when compared to external pressure dressing. Starck prefers the use of an external removable auricular stent (elastic dental impression material and a cotton roll) that is used to prevent hematoma after auricular cartilage procurement for TMJ reconstruction. After 10 days the there will be neocartilage formation that must be debrided. An anterior approach camouflaged in the scaphoid or conchal area then the cartilage and perichondrium are debrided then closed as above. The stent is worn for 7 days and the drain is removed in 2 days. This treatment should not disrupt lifestyle in the active patient. Congenital Aural Atresia General Atresia of the ear canal with middle ear anomalies can occur in isolation or in association with microtia or craniofacial dysplasia. The incidence is 1 in 10,000 to 20,000 births. Syndromes with aural atresia have a genetic link, this is not seen in isolated occurrence. One third of the cases are bilateral. The treatment of the problem is very challenging to the otologist. Embryology The external canal is derived from the first branchial groove and initially is a solid core of epithelial cells extending down to the tympanic ring and the first pharyngeal pouch. This core begins to absorb, medial to lateral, beginning the seventh month, a time when most structures of the inner, middle, and outer ear are well differentiated. Isolated branchial arch (ossicular) or branchial cleft (external ear canal) deformities are possible, but usually these malformations occur in combination. The stapes footplate is formed form the otic capsule, and in most cases, normal in a congenital ear. Facial nerve abnormalities are common in cases of aural atresia. The abnormal position of the mastoid segment places the nerve in jeopardy when drilling the posterior inferior portion of the new canal. Classification Canal atresia has been classified in several very confusing ways. The simplest is by Ombredanne who proposed dividing congenital ear atresia into two groups only, major and minor malformations. Major Malformations In this group the external ear canal and tympanic membrane are usually absent. The severe stenosis prevents visualization of the medial aspect of the ear canal. The size of the middle ear space is reduced, and the malleus and incus are deformed, fused and fixed to the atretic bone. Dehiscence or displacement of the facial nerve is present. Microtia is common, and inner ear function is usually normal. Minor Malformations The significant defect in the minor group involves the middle ear. There is absence or deformity of one or more of the ossicles or fixation of the ossicular chain. The middle ear space and tympanic membrane are normal. The external ear canal is patent, but may be mildly stenotic. Facial nerve positioning is usually normal as is the pinna. Patient Evaluation CT of the temporal bone (axial and coronal cuts) are necessary in all patients being considered for surgery. Cholesteatoma can occur in association with aural atresia. Management A child with unilateral atresia needs no initial management if the contralateral ear has normal hearing. Early amplification is essential with bilateral atresia. The concern of hearing benefit and risk to facial nerve with unilateral atresia the surgery is delayed until consenting adulthood. With bilateral atresia most surgeon recommend operation on the first ear as the child approaches school age and, depending on the hearing results, on the second ear within the next several years. In microtia patients the auricular reconstruction is started first using the virgin skin without unnecessary scaring. The repair of the external canal atresia requires drilling of the canal. Ideally, drilling is confined to the area just lateral to the middle ear space without entering the mastoid cavity. In most cases the ossicular chain, although deformed, is mobile, and hearing results may be better when the chain is left intact instead of interpostioning a prosthesis. A fascial graft is placed over the mobilized ossicular chain. A meatoplasty is performed by undermining the auricle and the deep soft tissue debulked from the approximate area of the meatus. A circular meatal opening about twice the normal size is made and a split thickness skin grafting to the newly made canal and bolstered with antibiotic impregnated Nu-Guaze. Ten days postoperatively the pack is removed. Acquired Aural Atresia: Acquired atresia of the external auditory canal is a fairly rare anomaly. It is usually the result of short-term or chronic inflammation of the skin in the auditory canal, but also from neoplasms, or trauma. To repair this requires a canalplasty techniques with bony widening and application of spilt-thickness skin grafts or full-thickness skin graft. A Z-plasty technique can also be used if the skin of the canal is adequate. --------------------------------------------------------------------------- BIBLIOGRAPHY: 1. Adamson PA, McGraw BL, Tropper GJ. Otoplasty: critical review of clinical results. Laryngoscope 1991;101(8):883-8. 2. Bailey BJ. Head and Neck Surgery - Otolaryngology. J.B. Lippincott Co. Chapters 116, 118, and 120. Philadelphia; 1993. 3. Brent B. Auricular repair with autogenous rib cartilage grafts: two decades of experience with 600 cases. Plastic Reconstr Surg 1992;90(3):355-74. 4. Cremers WR, Smeets JH. Acquired atresia of the external auditory canal-Surgical treatment and results. Arch Otolaryngol Head Neck Surg. 1993;119(2):162-4. 5. Cummings CW. Otolaryngology - Head and Neck Surgery. C.V. Mosby Co. Chapter 153 and 159. St. Louis; 1993. 6. Ellis DA. Keohane JD. A simplified approach to otoplasty. J Otolaryngol. 1992;21(1):66-9. 7. Fulmer RP. Otoplasty. Grand Rounds Dec 15, 1993. 8. Hendricks WM. 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