Severe auricular trauma is a rare injury. In addition to the type of injury, the location and the extent of the involved auricular structures have an important influence on the selection of an appropriate replantation or reattachment technique. A satisfactory primary reconstruction is not always possible to obtain and the remaining defects must be reconstructed secondary. The localization of the defect, its extent, and the condition of the tissue surrounding the defect are essential criteria for further treatment planning. This article provides an overview of the treatment of acute auricular trauma and of important aspects of secondary defect repair of the pinna.
Key points
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The success of a classic replantation as a composite graft is particularly dependent on the size of the amputated auricle segment and on the associated size and surface of the nutrient base.
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An important criterion for surgery planning is, in addition to localization, the size of the defect, its surface area, and depth.
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Small peripheral defects of the cranial third of the auricle may be reconstructed with typically cranially based transposition flaps.
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Fitting auricular defects, especially subtotal and total defects, with prosthetics plays an important role in the regimen of the reconstructive ear surgeon.
Introduction
Severe auricular trauma, especially complete amputations, is a rare injury. To date, less than 100 of these have been reported in the literature.
In addition to the type of injury, the location and the extent of the involved auricular structures have an important influence on the selection of an appropriate replantation or reattachment technique. The treatment options vary substantially, ranging from a simple restitching as composite graft up to a complex microvascular replantation.
A satisfactory primary reconstruction is not always possible to obtain and the remaining defects must be reconstructed secondary. The localization of the defect, its extent, and the condition of the tissue surrounding the defect are essential criteria for a further treatment planning.
This article provides an overview of the treatment of acute auricular trauma and important aspects of secondary defect repair of the pinna.
Introduction
Severe auricular trauma, especially complete amputations, is a rare injury. To date, less than 100 of these have been reported in the literature.
In addition to the type of injury, the location and the extent of the involved auricular structures have an important influence on the selection of an appropriate replantation or reattachment technique. The treatment options vary substantially, ranging from a simple restitching as composite graft up to a complex microvascular replantation.
A satisfactory primary reconstruction is not always possible to obtain and the remaining defects must be reconstructed secondary. The localization of the defect, its extent, and the condition of the tissue surrounding the defect are essential criteria for a further treatment planning.
This article provides an overview of the treatment of acute auricular trauma and important aspects of secondary defect repair of the pinna.
Surgery of auricular trauma
Classification
Different classifications of auricular trauma are described in the literature. Some are related to specific causes of injury (eg, sharp or blunt trauma, burn, chemical burn); others consider anatomic landmarks of the ear and the nature and extent of tissue trauma or tissue loss. For clinical aspects Weerda’s classification into four degrees of injuries has proved to be very useful ( Table 1 ).
| Classification of Auricular Trauma | |
|---|---|
| First degree | Abrasions without significant cartilage involvement |
| Second degree | Tear with nutrient skin pedicle |
| Third degree |
|
| Fourth degree |
|
Superficial Trauma (First Degree)
These cases are characterized by abrasions without or only a little cartilage involvement. The wounds are rinsed and the wound edges adapted and carefully sutured. Small defects are closed with small local skin flaps.
Tear with Nutrient Skin Pedicle (Second Degree)
Primary readaptation of the partially amputated part of the auricle is the best solution in these cases ( Fig. 1 ). Because of the excellent vascular supply of the auricle with many branches communicating with each other, even subtotal amputations with a very narrow skin pedicle (6 mm in width) can be reconstructed successfully.
Partial and Total Avulsion with Existing Segment (Third Degree)
The success of a classic replantation as a composite graft is particularly dependent on the size of the amputated auricle segment and on the associated size and surface of the nutrient base. However, the ischemic time of the amputated segment, which usually amounts to less than 4 to 6 hours, can almost be neglected based on animal studies by Weerda and colleagues and does not influence the success or failure of a direct replantation as a composite graft, even in microsurgical replantation. Direct reattachment as a composite graft can be achieved when the amputated part is smaller than 15 mm in diameter.
A direct readaptation of larger segments is rarely successful ( Fig. 2 ). Therefore, multistaged so-called pocket methods have been suggested. Their common characteristic is that the skin of the amputated auricle is in part or completely removed from the cartilage. The cartilage itself is then stored in a well-vascularized pocket, either in the ear region or remote area (abdominal, supraclavicular, cervical ). Other authors suggest repositioning of the cartilage and covering it with local skin flaps, with platysma, or with a temporoparietal fascia flap.
Another technique to salvage and reconstruct an amputated auricle has been described by Baudet and coworkers. He removes the posterior skin of the amputated auricle; creates little windows into the cartilage in the triangular fossa, scaphoid fold, and cavum conchae to allow an exposure and contact of the underside of the anterior skin to the vascularized bed; and replants it into its original position ( Fig. 3 ). He leaves the anterior skin intact and sutured it to the mastoid skin. In a second step some months later the auricle is lifted up and the retroauricular sulcus reconstructed with a skin graft.
The most important problem of all these techniques is a very high failure rate of about 60%. In addition, the delicate elastic cartilage is unable to withstand the contractile forces of scarring especially when using the pocket principle including its modifications. Because of distortion and flattening the contours of the auricular cartilage are lost in time so that the esthetic results are not convincing in a high number of cases.
In 1980, Pennington and colleagues reported the first successful microsurgical replantation of an auricle using vein grafts to the superficial artery and vein. Compared with all other techniques microsurgical replantation offers the best chance for success and shows excellent aesthetic results. Nevertheless, microvascular replantation is very challenging, not only because of the small vessel diameter less than 1 mm. Depending on the type of injury, an additional vessel damage by stretching and pressure may occur with an increasing risk of vascular complications, especially on venous congestion. A suitable vein cannot always be found in the amputated part, sometimes not even after successful arterial revascularization. In such cases and in cases of visible venous congestion it is essential to prevent or reduce a venous backflow problem using multiple skin punctures, stitch incisions, and leeches. Regarding several reports that venous connections between the replanted auricle and the recipient bed occur within a week after replantation, a venous drainage procedure should be performed during that time period.
The technique by Baudet can be summarized as an appropriate second choice if a microsurgical replantation is not possible. However, the pocket techniques should no longer be used.
Partial and Total Avulsion without Existing Segment (Fourth Degree)
Severe injuries to the auricular region with loss of the amputated auricle or auricle segment have to be covered by local skin flaps or free skin grafts. After some months the auricle can then be reconstructed secondary.
Secondary reconstruction of auricular defects
Defects and deformities of the auricle are not only caused by accidents or trauma. In addition they are the result of tumor resections and rarely of complications of aesthetic or reconstructive surgery using improper techniques. The techniques of reconstruction are, with the exception of the correction of microtia, in essence identical and follow standardized surgical principles.
Classification
An important criterion for surgery planning is, in addition to localization, the size of the defect and its surface area and depth. Based on the aforementioned variables, auricular defects may be classified simply and reproducibly in the everyday clinical setting ( Table 2 ).
| Classification of Auricular Defects | ||
|---|---|---|
| Central | Peripheral | Postauricular |
| Ear channel | Helix | |
| Concha | Upper part | Subtotal |
| Antihelix | Medial part | |
| Combined | Lower part, lobule | Total |
Moreover, the integrity of the tissue surrounding the defect is very important. Scar tissue, previous surgery, and previous radiation therapy may greatly affect and limit the techniques used. Therefore, this must be taken into consideration for surgery planning.
Central Defects
Skin defects of the concha are most effectively treated with a full-thickness skin graft as long as the perichondrium is intact. If not, the cartilage should be removed and a skin graft sutured onto the vascularized connective tissue underneath the cartilage. The retroauricular region of the ipsilateral, or alternatively, the contralateral side serves as the donor area.
Multilayer defects of the concha and the adjacent anthelix may be reconstructed with a cranial- or caudal-based retroauricular pedicled flap. Its pedicle can be severed after 2 to 3 weeks. This procedure may be performed in a similar manner to a transposition flap with a portion of pedicle epithelium being removed for tunneling or with a subcutaneous pedicled island flap from the postauricular sulcus.
The pedicle containing the posterior auricularis artery may be placed cranially or caudally. This is possible because of the perfusion in the case of a cranially based flap.
In extended central defects including the antihelix a large retroauricular cranially based bilobed flap by Weerda may be used. The anthelix should be reconstructed with rib cartilage ( Fig. 4 ).
