Surgical management of auricular trauma

Auricular anatomy

Mastery of auricular anatomy is a prerequisite for achieving successful reconstruction. The majority of the auricle is composed of an intricate cartilaginous framework with an overlying taut skin envelope, creating distinct topographical landmarks ( Fig. 3.1 ). The lobule lacks underlying cartilage and is made up of thin skin overlying fibrofatty tissue. Between the cartilage and skin along the posterior surface of the auricle exists a minimal amount of intervening adipose tissue, which is absent on the anterior surface of the auricle. The rich vascular supply to the auricle is derived from two branches of the external carotid artery: the superficial temporal artery and the posterior auricular artery. Venous drainage occurs via the superficial temporal, posterior auricular, and retromandibular veins into the external and internal jugular veins.

The average height and width of the adult auricle is 5–6 cm and 3–4 cm, respectively. In the Frankfort horizontal plane, the root of the adult helix is 6–7 cm posterior to the lateral canthus. The superior and inferior most points of the auricle align with the superior orbital rim and subnasale, respectively. The longitudinal axis of the auricle is inclined 15–20 degrees off the true vertical axis. The auriculocephalic angle, defined as the protrusion of the auricle from the scalp, is between 25 and 35°. The ear protrudes from the postauricular skin approximately 1.5–2 cm. Despite these established anthropomorphic standards for the ideal ear, auricular reconstruction is best modeled on the patient's contralateral ear to ensure symmetry and facial harmony.

Primary survey

Primary survey of the auricular injury should include assessment of the size, location and depth of the defect, viability of any avulsed segments and adjacent tissue, and patient goals based on comorbidities and trauma burden. A complete head and neck examination should be performed with special attention to evaluation of the tympanic membrane, presence of cerebrospinal fluid otorrhea, temporal bone fractures, facial nerve function, and external auditory canal (EAC) edema and lacerations. For lacerations extending into the EAC, a wick is placed to prevent canal stenosis, and otic drops are initiated until wick removal. All auricular injuries in the acute setting should be copiously irrigated and debrided of foreign bodies and visibly necrotic tissue. Tetanus and rabies vaccines should be administered if necessary. Topical antibiotic ointment is applied to all lacerations and open wounds. With regard to systemic prophylactic antibiotic therapy, superficial lacerations with intact perichondrium can be covered with a first-generation oral cephalosporin. For wounds with exposed cartilage in adults, oral fluoroquinolones are recommended to reduce the risk of auricular chondritis.

Principles of auricular reconstruction

The primary goal of auricular reconstruction is to restore the function of the auricle to converge, amplify, and transmit sound to the middle ear. The secondary, more formidable goal is to recreate the complex topographic landmarks and three-dimensional structure of the auricle and to maintain symmetry in its position, protrusion, height, and width when compared to the contralateral ear. For minor skin lacerations with intact perichondrium, the wound can often be closed primarily. If cartilage is exposed, the framework is reestablished either by primary repair or with use of cartilage grafts, with the most common donor sites being the conchal bowl, septum, and autologous rib. Any exposed or grafted cartilage must be covered with vascularized tissue. A multilayered, composite closure is performed with use of cartilage grafts, local advancement flaps, and skin grafts. Bolsters are applied to prevent hematoma or seroma formation and resultant auricular deformity.

Minor auricular trauma

Auricular hematoma

Auricular hematomas ( Fig. 3.2 ) result from accumulation of blood in the subperichondrial plane ultimately forming a dense, fibrin clot. A delay in clot evacuation can lead to an unsightly cauliflower ear deformity. Auricular hematomas are drained via a small, dependent incision down to cartilage overlying the area of fluctuance and hidden within a concavity of the lateral auricle. Dental roll or xeroform bolsters are contoured and secured to the anterior and posterior surface of the auricle via through-and-through large, nonabsorbable monofilament sutures in a quilting fashion to obliterate potential dead space and to prevent reaccumulation of the hematoma.