Chapter 79. Otoplasty & Microtia

Essentials of Diagnosis

• Prominauris (prominent ears) occurs in approximately 5% of the population.
• Conchal prominence and the absence of an antihelical fold represent the most common causes of prominence of the ears.
• Although there are hundreds of techniques to correct auricular prominence, the most common are suture techniques for conchal setback (technique of Furnas) and for creation of an antihelical fold (technique of Mustarde).
• Otoplasty refinement techniques exist for deformities such as large earlobes and excessive helical prominences.
• Complication rates from otoplasty range from 7% to 12% and may be subdivided into early, late, and aesthetic/anatomic in etiology.
• Auricular hematoma occurs in 1% of otoplasties. Complaints of unilateral pain or tightness within the first 48 hours postoperatively require prompt removal of dressings to examine the wound site for hematoma collection.

Preoperative Evaluation/Timing of Surgical Correction

The incidence of excessively prominent ears is about 5%. It is inherited as an autosomal dominant trait with 25% partial penetrance; it most commonly results from two anatomic irregularities, specifically the absence of an antihelical fold and excessive depth or projection of the conchal bowl.

Precise analysis of auricular deformities is paramount to achieving successful outcomes. Surgeons must identify the specific cause of auricular prominence in the formulation of an appropriate surgical plan. Although frequently bilateral, asymmetries in ear protrusion should be noted. As such, standard preoperative photography should be performed, including frontal, full right and left oblique, full right and left lateral, and close-up right and left lateral views.

Although there exist proponents of earlier surgical correction, most authors agree that the ideal age for otoplasty is between 5 and 6 years. Physiologically, the auricle is roughly 90% of adult height by 6 years of age. Psychosocially, correction is undertaken before or soon after a child's entrance to grammar school, where children are subject to peer ridicule. Moreover, by 5 or 6 years, children are able to participate in their own postoperative care (ie, not pulling off bandages or disturbing the wound).

Techniques of Surgical Correction

Over 200 techniques have been described for correction of the prominent ear. Conceptually, they can be subdivided into procedures that address an absent antihelical fold, procedures that reduce excess in the conchal bowl, and those that reduce prominent or enlarged lobules. Most of the latter techniques involve reshaping auricular cartilage, which can be accomplished through a number of cartilage-manipulating techniques such as suturing, scoring, and excision/repositioning, to name a few. Herein, the most commonly used technique for correction of an absent antihelical fold, originally described by Mustarde, is discussed in greater detail. In addition, the Furnas technique for reduction of an excessive conchal bowl is described.

Technique of Mustarde

In 1963, Mustarde first described a technique for creating an antihelical fold by using permanent conchoscaphal mattress sutures. Since that time, many subtle refinements of this technique have been described, but the fundamentals of the procedure remain unchanged.

Pediatric patients most commonly undergo general anesthesia for this procedure, and perioperative broad-spectrum antibiotics are administered. The face is prepped into a sterile field such that both ears can be visualized simultaneously. After infiltration with lidocaine 1% with epinephrine 1/100,000, an eccentric fusiform incision is made into the postauricular surface. Typically, more skin is excised from the postauricular surface than from the mastoid, in an effort to camouflage the resultant scar into the postauricular sulcus following setback.

Once the fusiform of skin is excised, the remaining skin of the posterior aspect of the helix, antihelix, and concha is undermined with scissors, leaving perichondrium attached to the auricular cartilage. The extent of antihelical fold creation is determined by pinching the anterior auricle with a thumb and index finger. Alternatively, some surgeons mark cartilaginous landmarks with several ink-dipped fine needles. Permanent horizontal mattress sutures (eg, 4–0 Mersilene [Ethicon, Inc., Somerville, NJ]) are placed into the helical cartilage, parallel with the helical rim at the lateral extent of the desired antihelical fold (Figure 79–1). It is critical that sutures are placed through the cartilage and lateral perichondrium but not the lateral helical skin. The first helical suture is placed at the level of the helical root to create the superior crus. The second suture is typically placed just inferior to the junction of the superior and inferior crura. Third and fourth sutures are placed as needed. Some overcorrection is necessary during placement of the most superior suture, because it has been demonstrated that as much as 40% loss of correction at this site may occur within the first postoperative year.

The wound is irrigated with antibiotic solution and closed with resorbable sutures. Antibiotic ointment, along with cotton impregnated in mineral oil, is applied to the new antihelix and postauricular sulcus, and a mastoid dressing is applied.

The dressing is removed on the first postoperative day to check for hematomas, and replaced for 3–4 more days. Subsequently, a head band is worn continuously for 2 weeks and at night for an additional 4–6 weeks.

Technique of Furnas

In 1968, Furnas popularized a technique of conchal setback using permanent conchomastoidal suturing. This procedure is often undertaken in conjunction with techniques to correct an absent antihelical fold, as described above.

The patient is prepped and draped in a manner similar to that described for correction of the antihelical fold. After infiltration of lidocaine 1% with epinephrine 1/100,000, a fusiform incision is made in the postauricular region. The width of the incision is estimated by manually pushing the concha toward the mastoid. Care is taken to avoid excessive skin excision, since tension on the wound predisposes to hypertrophic scar formation. Little to no skin excision is required inferior to the level of the antitragus. After excision of skin, soft tissue and postauricular muscle are excised from the postauricular sulcus. Sufficient soft tissue is excised to produce a pocket that will receive the concha during suture placement.

The skin over the helix, antihelix, and concha is undermined with scissors, and permanent horizontal mattress sutures (eg, 4–0 Mersilene [Ethicon, Inc., Somerville, NJ) are placed at the lateral third of the concha cavum and concha cymba parallel with the natural curve of the auricular cartilage (Figure 79–2). The sutures are thrown through cartilage and lateral perichondrium, but not lateral auricular skin. At least three sutures are placed for adequate setback. The sutures are placed on what was the ascending wall of the concha and, when tightened, convert the wall into a longer floor of the concha. For long-term successful conchal reduction, suture bites of mastoid periosteum must be taken. With extremely thick cartilage, as frequently seen in older persons, the cartilage may be weakened by excising small vertical ellipses of cartilage. It is important for the conchomastoidal sutures to allow the concha to be set not only medially but posteriorly. If not, external auditory canal stenosis can result.

The wound is irrigated and closed as after the Mustarde technique. A mastoid dressing is placed, and subsequent postoperative management is the same as that of antihelical fold surgery.

Otoplasty Refinement Techniques

Frequently, small deformities of the auricle are present that can be corrected by subtle surgical refinements. These techniques are applicable to both congenital irregularities and deformities that are detected after more substantial otoplasty correction (ie, conchal setback and correction of absent antihelical fold). Such refinements include correction of the prominent lobule and reduction of helical prominences.

Reduction of a large ear lobule rarely requires general anesthesia in the adult population. A new earlobe size is designed with a marking pen. After infiltration with local anesthesia, a fusiform incision is made anteriorly and posteriorly in a curvilinear fashion, and a V-shaped, wedge excision of lobule excess is performed (Figure 79–3). The skin is closed with permanent suture (eg, 6-0 nylon), with suture removal occurring on the sixth postoperative day.

Helical prominences, such as superior outer helical rim cartilage excess (ie, elf ears, Spock ears) and superior helical fold cartilage excess (ie, lop ear), may be corrected by a variety of helical reduction techniques. After the infiltration of local anesthesia, a fusiform incision is made on the outer helical rim in the case of helical rim excess and under the helical fold in the case of superior helical fold excess (Figure 79–4). After skin elevation, excess cartilage is shaved using a blade. Skin is trimmed as necessary to ensure appropriate draping over the cartilaginous rim. The incision is closed with permanent suture (eg, 6-0 nylon), with suture removal occurring on the sixth postoperative day. No pressure dressing is required.

Complications of Otoplasty

Overall, there is a high satisfaction rate among patients who undergo otoplasty surgery (85%). Complication rates range from 7% to 12%, with unsatisfactory aesthetic outcomes accounting for the majority of complications. Complications arising from otoplasty may be subdivided into early, late, and aesthetic/anatomic in etiology (Table 79–1).

Hematoma formation occurs following approximately 1% of all otoplasty procedures. Studies suggest a slightly higher incidence of hematoma formation in cartilage-cutting procedures compared with cartilage-suturing operations. Symptoms include unilateral or bilateral ear pain, usually within the first 48 hours after surgery. Hematoma formation may lead to perichondritis and the devastating sequelae of cartilage necrosis and ear disfigurement. Therefore, complaints of ear tightness or pain should be taken seriously with prompt removal of bandages and inspection of wounds. Infections after surgery typically manifest on postoperative day 3 or 4. Treatment involves systemic antibiotics, with particular emphasis on coverage for staphylococci, streptococci, and Pseudomonas aeruginosa.

Late complications include paresthesias of the ear, particularly to cold temperatures, which typically improve over 4–6 months. In addition, suture otoplasty techniques may result in complications surrounding permanent suture placement, such as suture extrusion and suture granuloma formation. These risks are minimized by meticulous placement of sutures. Hypertrophic scars or keloids may form as the wound heals, and conservative treatment with serial triamcinolone acetonide injections is indicated.

Aesthetic complications result from abnormalities in the relationship of the auricle to the scalp or from distortion of the auricle itself. These often stem from over-correction or undercorrection of the initial deformity. Often, an unsatisfactory outcome occurs when there is asymmetry between the left and right ear (typically, less than 3 mm difference in the mastoid-helical distance between left and right ear is satisfactory). Classic deformities include the “telephone ear” deformity that results from overcorrection of the middle third of a prominent ear. “Reverse telephone ear” deformity occurs when the midauricle protrudes after overcorrection of the superior pole and lobule. Alternatively, inadequate conchal setback may produce a similar aesthetic deformity. Isolated antihelical overcorrection, or “hidden helix,” produces the suboptimal appearance of the helix positioned medial to the antihelix on frontal view. All of the above aesthetic complications can usually be addressed through revision surgery, if desired by the patient.

Summary

Protrusion of the ears is a relatively common deformity. Successful surgical correction can relieve both children and adults of the psychosocial distress often associated with these deformities. An understanding of auricular anatomy and aesthetic ideals, plus with accurate analysis and meticulous surgical technique, can yield outcomes that are gratifying to both patient and surgeon (Figure 79–5).

Essentials of Diagnosis

• Microtia occurs due to abnormal development of hillocks during weeks 4 to 12 of gestational age
• Microtia is more prevalent in certain ethnic populations, including certain Latin American countries and the Navajo Indian population in the U.S
• Microtia has been linked to terataogens such as isotretinoin and thalidomide, but in the majority of cases the cause is unknown
• Microtia consists of disorganized remnant of cartilage attached to a variable amount of soft tissue lobule
• Microtia is treated by multistage auricular reconstruction starting after age 5 that preferentially utilizes costal cartilage, although alloplasts are preferred by some surgeons.

Background

Auricular malformations range from anotia to mild alterations in the external form of the ear. Microtia is a congenital malformation of variable severity of the external ear. The microtic auricle consists of a disorganized remnant of cartilage attached to a variable amount of soft tissue lobule, which often is displaced from a position symmetrical with the opposite normal ear.

Microtia occurs with a frequency of 1 in 5,000–20,000 births. It affects males more than females at a ratio of 2.5:1. Unilateral cases are much more common than bilateral cases with a ratio of 4:1. The right ear is affected more frequently than the left ear with a ratio of 3:2. The reason for this predilection remains unclear.

Microtia occurs with increased frequency in certain populations, such as in several Latin-American countries, and among the Navajo Indian community in the United States. The incidence of microtia is 1 per 900–1200 births in the Navajo population and 1 per 4000 births in the Japanese population.

Embryology

Microtia results from abnormal embryologic development of any of the six auricular hillocks. The six hillocks form the auricle during the sixth week of gestation. Abnormal development of the hillocks during weeks 4 to 12 of gestational age leads to auricular defects. Hillocks 1, 2, and 3 are derived from the first branchial arch and give rise to the tragus, helical crus and helix, respectively. Hillocks 4 and 5 form the antihelix, and hillock 6 forms the antitragus (see Figure 79–6).

While certain teratogens such as isotretinoin and thalidomide have been known to produce microtia, the cause in the vast majority of cases remains elusive.

Normal Anatomy

The structure of the auricle can be broken down into its integral elements all of which lend to the natural appearance of an ear. The main components include the helix, antihelix, scapha, triangular fossa, concha cymba, concha cavum, external auditory meatus, tragus, antitragus, and lobule. All these critical facets of the ear need to be present in order to achieve the perception of a normal ear.

The average length of the ear varies between 55 to 65 mm and the average width is 33.4 mm in females and 35.5 mm in males. The width is approximately 55% of the length of the ear. Conceptually, the ear can be divided into equal horizontal thirds. The first third extends from the superior helical rim to the upper border of the concha cymba. The middle third extends from the upper border of the concha cymba to the superior aspect of the antitragus. The lower third extends from the superior aspect of the antitragus to the end of the lobule (see Figure 79–7).

In the general population, the ear protrusion from the mastoid to the posterior surface of the auricle or auriculocephalic angle is 15°–20°. The inclination of the ear is usually 20° from the Frankfort plane. Many surgeons use the inclination of the nasal dorsum as guide. However, this is not an accurate measure, since the average nasal dorsum usually lies approximately 30° from the Frankfort plane.

Types of Microtia

While no universal classification system of microtia prevails, there are several widely used staging systems. Marx described a system based on the degree of deformity and specific anatomic parts.

• Grade 1 microtia is characterized by an abnormal auricle with all identifiable landmarks.
• Grade 2 microtia consists of an abnormal auricle without some identifiable landmarks.
• Grade 3 microtia is recognized by a very small auricular tag
• Grade 4 microtia is anotia.

Weerda described a similar system consisting of only three grades.

Grade I microtia is characterized by a mild deformity with a slightly dysmorphic helix and antihelix, as depicted in the first image below. All the major structures are present, and no additional cartilage is necessary during surgical repair. Characteristic lop ear and cup ear abnormalities are categorized into this group.

Grade II microtic ear deformities have all major structures present to some degree, but repair requires cartilage or skin. The grade III abnormality has few, if any, landmarks. The lobule, if present, is usually positioned anteriorly. Peanut and anotic ears are examples of grade III malformations (see Figure 79–8).

Surgical Repair

Various methods of reconstruction have been advocated throughout the years, including the use of autologous rib cartilage versus the use of a prosthesis. Autogenous cartilage is our favored choice because of lower resorption rates, lower extrusion rates, ability to grow and ability to withstand trauma. A relatively new area of research involves using cultured chondrocytes to create a cartilaginous framework. While this continues to be an area of interest, it is beyond the scope of discussion for this chapter and will not be discussed here.

A child with microtia should be evaluated at an early age with appropriate referrals made for audiologic testing and for an otologist, if there is evidence of hearing loss and/or middle ear deformities. Timing of microtia repair is based on physical maturity, psychological development and the patient's social milieu. By the age of 6, the thoracic cavity increases in size and strength such that there is adequate donor cartilage available. As the child grows, more cartilage becomes available facilitating reconstruction. However, the benefit of availability of greater cartilage needs to be weighed against the patient's social situation, such that it is performed at a time when it limits the psychological effects of peer ridicule and teasing. The psychological effects of such teasing generally do not manifest before ages 7–10. If a child does not have the developmental maturity to manage with the critical early postoperative period, surgical repair should be delayed.

Atresia repair needs to be delayed until after all the auricular reconstruction has been completed. This allows for establishing the auricular position before creation of an external canal, ensuring appropriate symmetry. Secondly, it allows auricular reconstruction to occur with an unadulterated blood supply.

Architecture

The architecture of the auricle is composed of several key components which need to be understood in order to achieve a quality repair. The first defining quality is the general outline of the auricle, which is essentially an oval shape with a slightly flattened area posteriorly. A second defining characteristic is a line that defines the helical rim from its root and the crus helicus. A third line defines the concha, tragus, and antitragus (see Figure 79–9. Finally, the fossa triangularis needs to be highlighted to achieve a realistic appearance to the framework.

The reconstructed ear should be symmetric with the contralateral ear, especially with respect to vertical position, length, and protrusion, as these are the qualities which can be accessed from an anterior view. Asymmetries of the two sides of the face are noted in up to 88% of microtia patients, due to generalized abnormalities in the development of the branchial arch. As a result, measurements of the lower one-third of the face can be deceptive.

Reconstruction

Traditional microtia reconstruction generally occurs in four stages with each stage-taking place 3 to 4 months after the preceding stage. The first stage involves harvesting the rib cartilage, carving, and creating an auricular framework, and placing it under a subcutaneous pocket. The second stage involves rotating the lobule from the microtia remnant and positioning it inferiorly on the helical rim. The third stage encompasses creating an auriculocephalic angle by elevating the framework off the skull and placing a skin graft on the undersurface of the framework. The fourth and final stage involves forming the tragus, and possibly the conchal bowl. It cannot be overemphasized that no incision should be made until a multistage plan is outlined prior to start of the first stage. Incisions for all subsequent stages should be planned prior to starting the first phase in order to maximize blood supply for all subsequent reconstructions.

Stage I

In this first and most critical of the four stages, rib cartilage is harvested, carved and placed under a cutaneous pocket. The normal ear is used to trace out a template on x-ray paper and appropriate measurements made on the microtia side. Next, the contralateral sixth to eight rib cartilages are harvested in continuity (see Figure 79–10). This curvature mimics that of the contralateral ear. The cartilage is then carved and sculpted to match the template (see Figure 79–11). At the end of the rib harvest, the wound should be irrigated while positive pressure ventilation is provided in order to evaluate for an air leak and therefore a pneumothorax.

The microtia harvest incision should be placed in a location that avoids compromising blood flow and can be incorporated into a future incision site. The microtia remnant is carefully dissected free from the overlying skin. A pocket for the framework is dissected such that it is 1–2 cm larger than the framework. The placement of the framework is based on the location of the normal ear and not on the position of the hairline or the desired location for the external auditory meatus. The framework is placed into the pocket and held in place with the use of the suction effect of two small drains. The convolutions of the ear are packed gently with Xeroform in order to maintain their shape (see Figure 79–12).

Stage II

The second stage, referred to as the lobule transposition, can be performed within 6–8 weeks of the first stage. The surgery is performed by transposing the vestigial lobule along an inferiorly based pedicle. The helical rim of the framework created during the first stage needs to be incised and tailored to allow attachment of the lobule equally on either side of the framework (see Figure 79–13). This stage can be performed under local anesthesia in cooperative patients.

Stage III

The third stage involves creating the auriculocephalic angle. After the postauricular area is shaved and prepped, an incision is made extending from the anterior crus, anterosuperiorly, to the antitragus inferiorly. If the lobule requires repositioning, the incision is continued around the entire lobule. The framework is then dissected free from the underlying soft tissue of the mastoid region. A pocket is dissected in the lobule to allow placement of the inferior aspect of the framework.

The skin posterior to the incision is undermined widely in the superior, posterior, and inferior directions. This flap is then advanced to fill in the defect in the new postauricular region. A split thickness skin is harvested from the patient's hip and cut to the size of the defect along the posterior aspect of the elevated ear. The skin graft is sutured in place with a Xeroform bolster is sutured to the postauricular surface. Of note, greater projection of the ear can be obtained by placing a piece or rib cartilage behind the elevated ear and placed under the subcutaneous pocket (see Figure 79–14).

Stage IV

The fourth stage involves creation of the tragus. A composite graft is harvested from the contralateral ear conchal cartilage. In bilateral microtia, a piece of cartilage and skin from the microtia remnant can be used to create the tragus. A “J” incision is made in the location of the planned posterior border of the tragus. The primary limb of the “J” is placed in the posterior tragal margin, while the curve is placed in the intertragal notch (see Figure 79–15). Once an adequate flap is created anteriorly to receive the composite graft, it is then placed and sutured into place along the undersurface of the flap. Cotton bolsters are sutured onto both the anterior and posterior aspects of the newly created tragus, in order to secure the graft and create a pretragal sulcus.

Use of Synthetic Implants

An alternative to antilogous rib cartilage is the use of synthetic prefabricated auricular framework. The most popular of these is porous high-density polyethylene (PHDPE, Porex). It is an inert, noncompressible product that is pliable when heated and can be shaped further. It also has good tissue compatibility and ability to accept tissue ingrowth into its framework. Advantages of its use include the elimination of a chest incision and associated morbidity. Critics cite incidents of implant exposure and infection rates as reasons not to use implants. Some pitfalls of synthetic implants and prostheses include the fact that they are firmer than autogenous grafts, are relatively immobile, are less delicate and are more prone to traumatic injury.

Complications

In Brent's earlier series, he reported a complication rate of 1.6%, but in a more recent series of 1200 cases, he reported no complications. Complications after autologous reconstruction are uncommon, but range from risk of skin loss, cartilage exposure, infection, hematoma, malposition, graft resorption leading to poor contour, scar contracture, pneumothorax, and atelectasis. Skin loss and cartilage exposure can be prevented by careful examination of the repair at the conclusion of the case. If there is any evidence of skin blanching or undue tension, the cutaneous pocket should be made larger or the projection of the framework should be reduced. Preoperative antibiotics, thorough skin prep, sterile technique and postoperative hygiene are key components in preventing infection. Careful hemostasis and the use of suction have been shown to be useful in preventing hematoma.

Intraoperative pneumothorax is a complication, which can be easily treated. A red rubber catheter should be placed in the pleural opening and any residual air removed using a syringe. A chest x-ray should be obtained immediately after closure of the wound. If there is no pneumothorax, the red rubber catheter can be removed after closure. The patient should be followed with serial x-rays.

Summary

Microtia is an uncommon congenital deformity, which is nonetheless psychologically and socially disturbing to the child affected by it. Careful patient selection and thorough patient education, combined with detailed surgical planning and technique, facilitate successful outcomes. Complications can be prevented with judicious preparation and some foresight. The use of autologous cartilage versus an implant is a decision that should be made not only based on surgeon experience with the procedure, but with consideration to patient candidacy as well.