Dermatologic Approach to Ear Reconstruction

Reconstruction of the ear can be a complex process. The 3-dimensional nature of the ear with its many curves, peaks, and valleys demand the utmost attention to detail. Yet, as challenging as it may seem, reconstruction of the ear can be made easier and predictable if one understands the anatomy and basic surgical principles.

The techniques discussed in this article address defects that result from skin cancer excision. More than 5 million cases of basal cell carcinoma, squamous cell carcinoma, and malignant melanoma occur per year in the United States.[1] Greater than 85% of nonmelanoma skin cancers occur on the head and neck, with a significant portion of these malignancies arising on the ear because of its exposure to the sun.[1, 2] All areas of the external ear are at risk for skin cancer, especially the helix and antihelix areas of the ear. Compared with other cancers, these tend to be more aggressive with higher recurrence rates. Given this setting, the defects on the ear can be relatively large.

Reconstruction of the ear is indicated when a defect is present after skin cancer extirpation. The reconstruction methods discussed in this article all follow the principles of Mohs micrographic surgery. Certain small defects may not need reconstruction and can heal by second intention. This concept is also discussed below.[3]

The external ear is composed of skin and cartilage with the supporting nerves and blood vessels. The auricular cartilage provides a framework for the entire ear except the lobule. The tightly adherent skin extending from the preauricular sulcus to the helix produces distinct topographical landmarks on the anterior surface of the ear that are important in understanding and describing the ear (see the first image below). The concavities include the triangular fossa, the scapha, the cymba, and the cavum of the concha. The helix, the antihelix, the tragus, and the antitragus form the convexities. The skin on the posterior (medial) aspect of the ear that extends to the postauricular sulcus is less adherent to the underlying cartilage (see the second image below).[4]

A well-proportioned ear is 50-60% as wide as it is high. The ear is positioned one ear length from the lateral orbital rim, and the top of the ear is level with the eyebrow and tilted back by 20°.[5]

The auriculotemporal nerve, a branch of cranial nerve V3 innervates the superior aspect of the anterior surface of the ear. The lesser occipital nerve and the great auricular nerve are both derived from C2 and C3. The lesser occipital nerve innervates the superior aspect of the posterior surface. The great auricular nerve innervates the lower portion of both surfaces. The vagus nerve supplies the concha.

The ear is well vascularized, an important feature because most flaps are based on a random blood supply. The superficial temporal artery and the posterior auricular artery are branches of the external carotid artery and supply the anterior and posterior surfaces, respectively.[6] Because of the rich blood supply and collateralization, anesthetics that contain epinephrine can be used safely.

Reconstruction of the ear has relatively few contraindications. If the patient can tolerate the initial Mohs micrographic surgery, they can usually tolerate the subsequent reconstruction as well, although the complexity of the reconstruction may need to be tailored to the patient's medical state. In patients whose medical condition precludes surgery, other treatment options, such as superficial radiation therapy (SRT), should be considered.

The patient's medical history should be assessed prior to surgery. Aspirin and warfarin increase the risk of intraoperative and postoperative bleeding complications, but their discontinuation can lead to life-threatening medical complications. Current guidelines recommend continuing all antiplatelet and anticoagulant medications.[7] However, a 2021 study supports the safety of perioperative discontinuation of direct oral anticoagulants such as apixaban and rivaroxaban.[8] Each case should be approached in an individualized manner and if hesitant to move forward with a case, it is best to consult with the patient's cardiologist or managing physician before stopping any anticoagulants.

The defects addressed below can occur as a result of Mohs micrographic surgery or excisional surgery to treat skin cancers. As with any reconstruction, proper planning is paramount to a successful outcome.[9] A thorough understanding of the defect's size, anatomical location, depth, affected tissues, and auricular subunits is key. Flaps, grafts, and primary linear closures can be used in reconstruction of the ear. Healing by second intention is also a valuable tool. The reconstruction technique best suited for a given defect is determined by the size, shape, depth, and location of the defect. The goal of reconstruction is to restore the form and function of the ear.[10]

An important principle in ear reconstruction is that the entire anterior surfaces of both ears cannot be viewed simultaneously. Therefore, reconstructing the ear so that it is not distorted or deformed is important, but one ear does not have to exactly match the contralateral ear in terms of its size and appearance. The ear also has a functional importance for many patients as a supporting structure for eyeglasses.[11]

Probably most important to the dermatologic surgeon, the helix is commonly divided into the upper, middle, and lower subunits, and reconstruction approaches can differ greatly depending on the subunit.

Owing to the common use of hearing aids and eyeglasses, a primary goal of repair is to maintain the structural integrity of the upper helical subunit. For small defects not affecting the cartilage, primary closure, secondary-intention healing, or skin grafting can suffice. If structural cartilage is involved, composite grafts, advancement flaps, and wedges are commonly used.[11, 9] Reconstruction of the middle third of the helix can also require more advanced repairs, but maintaining structural integrity is not required. In the lower third of the helix, the lack of underlying cartilage and larger tissue reservoir allows direct linear closure and small wedge excisions to meet the majority of the surgeon's needs.[9]

The reconstructions are categorized on the basis of the anatomic location of the defect. The regions are divided into the helix, the anterior surface, the posterior surface (preauricular sulcus and postauricular sulcus), and the lobule.

Helical defects

The underlying shape and curvature of the auricular cartilage gives rise to the contour and rigidity of the helix. The helix arises from the helical root and curves in a semicircular fashion upward then downward to the lobule. The lobule does not contain cartilage. Maintaining the shape and contour of the helix is paramount in recreating a normal-appearing ear. Even a subtle deviation from the normal curvature or a disruption in the contour can lead to an abnormal appearance of the ear.

Primary linear repair

Small helical defects with intact cartilage can be repaired with linear layered closures (see the image below). However, this type of closure does narrow the width of the helix. To better blend this narrowing, the length of the closure may need to be lengthened to taper this effect over a longer surface area. Even in larger defects in which cartilage is missing, primary linear closures can sometimes be used. If a patient's underlying comorbidity precludes a complicated closure, the exposed cartilage can be trimmed and the anterior and posterior skin simply reapproximated (oversewed).

Wedge excision repair

Defects on most aspects of the helix can be repaired with a wedge excision (see the image below). The principle behind the wedge closure is the conversion of the defect into a full-thickness (anterior skin, cartilage, posterior skin) triangular wedge. Ideally, the inner corner of the wedge is 30° or less to minimize the formation of a dog ear.

For larger defects, full-thickness Burrow triangles can be superiorly and inferiorly excised to form a star (see the image below). Results are best in defects less than 2.5 cm in diameter.[11] The wedge is repaired by carefully reapproximating each layer (ie, posterior skin, cartilage, anterior skin). The helix must be meticulously realigned to prevent notching. The use of vertical mattress sutures on the helix helps prevent this cosmetic complication. The ear wedge always makes the ear smaller; therefore, the size of the defect is the limiting factor.

With defects smaller than 1.5 cm, the shape and appearance of the ear is preserved.[12] With larger defects, the likelihood of distortion and deformity increases. Larger ears can tolerate larger wedge excisions and vice versa.

Chondrocutaneous advancement flap procedure

Defects confined to the helix with or without a cartilage defect can be repaired with the chondrocutaneous advancement flap, or Antia-Buch chondrocutaneous advancement flap. This flap is used for moderate-sized defects on the helical rim. The skin of the helix and the underlying cartilage are either unilaterally or bilaterally advanced.

The flap has two variations. The first variation uses a modified O-to-T advancement. The flap can be of full thickness and detached on both the anterior and posterior surfaces of the helix. This construction allows for maximal extension of the flap. The entire posterior skin is undermined to elevate the flap. Then, the flap is advanced with a wedge that is removed posteriorly (see the images below). The helix must be meticulously realigned.

In the second variation, the flap can be designed with the posterior skin intact, leaving a broader flap base as Antia and Buch originally describe.[13, 14] In either variation of the flap, a Burow triangle may need to be excised if the defect is large. Additional length can be gained by using a V-to-Y advancement of the helical root.[15] The ear is smaller than it is at the baseline. However, it is not as small as it would be with a wedge excision closure because of the stretch provided by the flap and smaller sacrifice of the cartilage. The use of the chondrocutaneous advancement flap is usually limited to defects 2.5 cm or smaller.

Banner transposition flap procedure

Defects on the superior aspect of the helix are ideal for repair with the banner transposition flap. Originally described with use of the postauricular skin, the loose preauricular skin can also serve as the donor site for the flap (see the image below).[16, 17, 18] The base of the flap is superior and contiguous with the defect; this construction allows for the flap to be draped onto the defect. To preserve a wide flap base, the posterior dog ear must be removed with an incision away from the base. This flap can be used only for defects of the skin or for defects of both the skin and cartilage.

If a large portion of the cartilage is missing, a cartilage graft from the contralateral ear can be used. For more superior defects not involving the region of the helical root and not contiguous with the preauricular skin, the transposition flap can be converted to a tubed pedicle flap to cross over the intact intervening skin. The pedicle remains attached for approximately 3 weeks while the flap develops an adequate blood supply. The pedicle is then sectioned, and the flap is trimmed to fit the defect.

Bilobed flap procedure[19, 20]

Defects on the superior and mid helix can be repaired with a bilobed flap. Ideally, the cartilage should be intact, but the flap has enough bulk to offset a small cartilage defect. The loose postauricular skin is easily undermined and serves as the donor site for this flap. The classic bilobed flap has a base that is 180°, with 90° between each lobe. This flap can be modified to decrease the angles between the lobes to reduce the movement and the size of the dog ears (see the images below).[21] The pivot point of the flap must be understood to enable correct measurement of the appropriate length and width of the flap. Defects as large as 2 cm can be repaired with a minimal reduction in the size of the ear.

O-to-T advancement

The O-to-T advancement flap is useful for defects that are predominantly on the posterior aspect of the helix. The flap allows for the repair of the helical contour without a significant reduction in the size of the ear or narrowing of the helix. It can be used in areas where the donor skin is insufficient for a bilobed flap. A longitudinal incision is made along the helix, and the flap is lifted off of the skin on the posterior part of the ear. The flap is advanced together to cover the defect (see the images below).

Anterior surface defects

The triangular fossa, the scapha, the antihelix, and the concha are the regions inside the helical rim. Defects in these regions must be assessed for involvement of only the skin, the skin and perichondrium, or the skin and cartilage. Skin grafts are useful in covering a wide variety of ear defects. If the perichondrium is present, a full-thickness skin graft can be applied. Depending on the size of the defect, the common donor sites are the preauricular skin, the postauricular sulcus, or the supraclavicular skin.

Split-thickness skin grafts (STSGs) can also be used, although the color and texture match may not be as good as with other methods.[22] STSGs have an advantage in that they can survive even if the entire perichondrium is not intact. If no perichondrium is present, the cartilage can be excised to reveal the posterior skin of the ear. For most defects within an intact helix, enough structural support is present even without the cartilage. A graft can be placed on this vascular bed (see the image below). Grafts placed in the concha should be generously sized to compensate for the profound concavity.

Small defects can heal by second intention whether or not the perichondrium is intact. If the perichondrium is absent, small holes should be made through the cartilage to facilitate healing from the posterior skin (see the first image below). Concave or flat surfaces are ideal for second intention healing because the resultant scar is usually slightly depressed (see the second image below). If the defect extends into the external auditory canal, an STSG should be placed to prevent strictures of the canal.[23]

Preauricular sulcus defects

Defects in this region often extend onto the tragus and the helical root. Because of the laxity of the cheek skin, a flap can be raised and advanced posteriorly to close the defect (see the image below). Loss of the tragus and subtle loss of the helical root are usually unnoticeable from a frontal view. The resultant scar blends nicely into the face-lift line.

Postauricular sulcus defects

Skin cancers in this region are relatively large because they can go unnoticed for long periods. Defects on the posterior surface can be closed with grafts, flaps, or primary closures as described above. Many cancers arise in the sulcus. The defect straddles the sulcus, resulting in premastoid and posterior ear components that are similar in size and shape. STSGs are commonly used to cover large defects, but they may result in the anterior protrusion of the ear.

A simpler repair technique is to pin the ear back, adjoining both sides of the defect in a fashion similar to closing a postauricular skin graft donor site. Large defects encompassing almost the entire posterior surface of the ear can be closed in this manner (see the first and second images below). A single layer of modified vertical mattress sutures (typically 3-0 Vicryl) is used to close the entire defect. The modification entails grabbing the base of the sulcus with the suture to close the dead space. The sutures are left untied until all the vertical mattress sutures are in place (see the third image below). The sutures are removed in 2 weeks.

Although the postauricular sulcus becomes narrower than the contralateral ear, it typically does not appear asymmetric from either the frontal or the posterior views. If tacking back of the ear is thought to be too excessive for the patient, the wound edges can be pulled slightly apart at the time of suture removal and allowed to heal by secondary intention.

Split bilobed flaps have been used to repair composite posterior auricular and mastoid defects.

Lobular defects

Defects of the lobule and lower helix can be repaired with either a primary linear closure for partial-thickness defects or wedge excision for full-thickness defects. Defects involving as much as 50% of the lobule can be repaired in this fashion without significant cosmetic or functional deficits (see the image below). To prevent notching or separation, wound eversion is important.

Given the great number of skin cancers on the ear, a tremendous variety of defects can result from their treatment. A systematic practical approach must be adopted to meet the challenge of these defects. By categorizing the defects by their size and location, these defects can be reproducibly repaired to restore the symmetry, aesthetics, and function of the ear.