Repair of Auricular Defects




Repairing defects of the auricle requires an appreciation of the underlying 3-dimensional framework, the flexible properties of the cartilages, and the healing contractile tendencies of the surrounding soft tissue. In the analysis of auricular defects and planning of their reconstruction, it is helpful to divide the auricle into subunits for which different techniques may offer better functional and aesthetic outcomes. This article reviews many of the reconstructive options for defects of the various auricular subunits.


Key points








  • Repairing defects of the auricle requires an understanding of the complex underlying framework, the structural properties of the cartilages, and typical healing tendencies of the surrounding tissues.



  • The auricle is divided into various subunits: central (anterior auricle, posterior auricle) and peripheral (superior, mid, inferior).



  • The optimal reconstructive approach for any given auricular defect will depend on its specific location and the quality of the surrounding available tissues.




The human auricle is an important component of facial aesthetics with functional, cultural, and physiologic significance. Not only is it a sound gathering structure but we rely on it practically for modes of cultural expression and support for eyewear. Asymmetry or deformity of the ear is obvious, even by the untrained eye. The auricle is composed of multiple subunits with numerous convexities, concavities, varying skin thickness and a complex underlying cartilaginous framework ( Fig. 1 ). Accordingly, reconstructing a functional and aesthetically pleasing auricle is challenging. As a general principle, size, projection, tissue matching, and contour are all important considerations with the understanding that the goal is to create a likeness that incorporates as many of the features of a normal auricle as possible.




Fig. 1


The underlying cartilaginous framework of the auricle. ( A ) Anterior. ( B ) Posterior.


When considering any individual reconstruction, not limited to the auricle, it is vital to evaluate all possible options. The paradigm of the reconstructive ladder involves considering reconstructive methods starting with the simplest and progressing to the most complex. For any given site of reconstruction, the chosen method should represent an optimal balance of factors, such as aesthetic result, restoration of function, recovery time, operative time, and donor site morbidity. The simplest method for reconstruction at any site is to close the defect primarily. However, in many instances this can lead to an unfavorable aesthetic outcome and is not always possible given the size or location. Secondary intention is a very useful method; however, it can also have negative cosmetic or functional results. Both primary closure and secondary intention are great options for many small defects; however, the additional time allocation for healing and wound care must be taken into consideration if the wound is to heal by secondary intention. Skin grafts and local flaps are excellent options in certain settings and can be easily undertaken. Composite grafts and free distal flaps have significantly more involvement and require more surgical expertise and comfort with these options; however, sometimes these latter choices are necessary.


With respect to repair of auricular defects, primary closure and secondary intention are the least complex options and work well for many small defects. Although secondary intention may initially be one of the simplest approaches, longer healing times and the ability of the patient to perform the necessary wound care should be considered, particularly if the patient is elderly or has difficulty lifting his or her hands to the affected area. If the cartilaginous framework is intact, free skin grafts may be used to cover larger defects. For anterior defects, full-thickness grafts are generally preferred, though split thickness grafts may suffice in patients with thin skin. Both the lateral neck and preauricular skin are convenient donor sites and typically offer good color match; however, the postauricular skin tends to be a good match as well and favorably hides the donor wound. If the vascular supply in the wound is not sufficient enough to support a free dermal graft, then local random flaps are preferred and tend to do well given the rich blood supply within the dermal plexus of skin surrounding the auricle. Large defects with missing cartilaginous framework often require the use of local flaps and composite grafts to provide structural support and coverage with vascularized tissue. Although the focus of this article is the repair of postsurgical defects, it is important to know that microvascular surgery has been used successfully in the acute trauma setting for reimplantation.


Preoperative planning is essential for the reconstruction of auricular defect. It is important to determine the specific anatomic subunits involved because each subunit has unique characteristics. The structural integrity, skin thickness, contour, and visibility of the subunit involved, and the availability of healthy surrounding tissues will determine which reconstructive option will give an optimal result.


For purposes of analysis, the auricle is divided into central and peripheral zones. The peripheral auricle is divided into 2 main subunits: the helix (which is further subdivided into thirds) and the lobule. The central zone of the auricle is divided into anterior and posterior regions. The anterior central zone is divided into subunits, including the concha, helical root, and antihelix. The posterior central zone does not have further subdivisions. Table 1 summarizes the analytical zones of the auricle. Table 2 summarizes some of the highlighted reconstructive options for each of these areas.



Table 1

Analytical zones for auricular reconstruction














Central Peripheral
Anterior Posterior
Concha
Helical root
Antihelix
Entire posterior surface Helix (upper, mid, lower)
Lobule


Table 2

Reconstructive summary for auricular defects by size and analytical zone








































Location Small Defects Large Defects
Total Microtia-type repair
Temporoparietal fascia flap with autologous cartilage or synthetic implant
Prosthesis
Peripheral
Helix, upper 1/3 Secondary intention
Full-thickness skin graft
Helical advancement
Pre- or postauricular transposition flap
Staged retroauricular tube flap
Helix, mid 1/3 Secondary intention
Full-thickness skin graft
Helical advancement
Wedge excision
Staged retroauricular advancement flap
Composite wedge graft from contralateral ear
Helix, lower 1/3 Secondary intention
Full-thickness skin graft
Helical advancement
Composite wedge graft from contralateral ear
Lobule Primary closure Bilobed flap
Central
Anterior (concha, helical root, antihelix) Secondary intention
Full-thickness skin graft
Retroauricular pull-through flap (concha, antihelix)
Preauricular pedicle flap (helical root)
+/− cartilaginous struts
Posterior Secondary intention
Primary closure
Full-thickness skin graft
Split thickness skin graft




Total or near total auricular defects


One of the most challenging types of facial reconstructive surgery is recreating the entire auricle. When a patient is left with a total or near total auricular defect, a prosthesis should be considered. By using a mold created from the contours of the contralateral ear, a prosthesis can be fashioned that provides an excellent cosmetic result. The lack of further local tissue disruption or rearrangement is particularly helpful when tumor surveillance is needed. Prostheses can be attached to osseointegrated implants in the mastoid region if necessary.


When total auricular reconstruction is required, a staged approach is necessary with the use of autologous tissue. At the initial stage, rib cartilage should be harvested and the new cartilage framework sculpted ( Fig. 2 ). Harvesting cartilage from the contralateral 6th to 8th ribs is optimal; leaving a superior margin of the 6th rib cartilage in place will help to prevent chest deformity. The contralateral ear is used as a template to determine the appropriate amount of cartilage to harvest. The use of 3-dimensional (3D) modeling techniques based from the contralateral ear has been shown to be useful in reconstructive efforts, and this relatively new technology is becoming increasingly accessible. The components of the new cartilaginous framework are sutured together and then implanted in a postauricular subcutaneous pocket. At a subsequent staged procedure, the lobule is transposed ( Fig. 3 ). The auricle is elevated from the head at the next staged procedure, and a skin graft is placed postauricularly to define the posterior margin of the auricle ( Fig. 4 ). The tragus may be created using a graft from the contralateral ear ( Fig. 5 ).




Fig. 2


Harvest of rib cartilage and implantation. ( A ) Cartilage can be taken from the confluence of the 6th to 8th ribs on the contralateral side. ( B ) Harvested cartilage is sculpted and sutured together to create the new auricular framework. ( C ) Placement of the assembled new framework is inserted into a subdermal pocket over the mastoid with suction drains in place.



Fig. 3


Lobular transposition. ( A ) The auricular-lobular remnant is elevated to create an inferiorly based flap. ( B ) The inferior portion of the cartilage is exposed before the lobular remnant is rotated inferiorly to cover the cartilage. ( C ) The donor area, which is closed primarily, will become the tragus.



Fig. 4


Auricular elevation. ( A ) An incision is made several millimeters beyond the margins of the underlying auricular framework. ( B ) The auricular framework is elevated. A wedge of harvested cartilage can be used to create the auriculomastoid angle. The cartilage wedge can be covered with a small temporoparietal fascial flap. ( C ) A skin graft can be used to cover the posterior surface of the temporoparietal fascial flap and cartilage wedge.



Fig. 5


Creation of the tragus. ( A ) The skin of the neoconcha can be used to create an anteriorly based flap, under which a crescent-shaped cartilage graft is placed and sutured in place to create the neotragus. ( B ) The conchal defect is usually covered with a full-thickness skin graft.


Another option for augmenting repair of near total defects is the use of the temporoparietal fascia flap, based from the superficial temporal vessels ( Fig. 6 ). This flap can be used to provide a significant amount of vascularized tissue that is robust enough to support both the autologous costal cartilage graft and overlying skin graft, and it may be helpful in the postradiated or other complex field.


Aug 26, 2017 | Posted by in General Surgery | Comments Off on Repair of Auricular Defects
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