Facial trauma remains a common reason for visits to the emergency department or urgent care facility. The ear remains susceptible to trauma given its delicate anatomy and position in the maxillofacial region. Understanding the anatomy and recognizing the circumstances regarding the mechanism of injury help dictate treatment. The goals of treatment should remain to restore the physiologic form and function of the ear. Middle ear injuries should also be addressed during the process. Although primary repair remains feasible in most cases, there are instances when delayed and staged reconstruction is necessary to achieve successful results.
Key points
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The ear is prone to varying degrees of trauma given its position in the maxillofacial region.
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Understanding the anatomy of the ear remains paramount when repairing the ear.
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Reconstruction can take place in a staged approach to provide the best esthetic and functional outcomes.
Introduction
Facial trauma remains a common initial presentation in many emergency departments and urgent care facilities. Because of its delicate anatomy and prominent position, the ear remains a common structure that is routinely damaged. External ear injuries include simple and complex lacerations, hematoma formation, as well as varying avulsive injuries. Health care providers must also assess these patients for middle ear injuries and possible temporal bone injuries during the examination. Once an initial evaluation has been completed, treatment and repair of the injuries may proceed accordingly.
Anatomy
The anatomy of the ear can be subdivided into 3 sections: the external ear, middle ear, and inner ear. The outer ear includes the auricle ( Fig. 1 ) and the external auditory meatus, which leads into the external auditory canal (EAC), terminating at the tympanic membrane. The auricle is supported by elastic cartilage. Overlying the anterior portion of the cartilage is tightly adherent skin and connective tissue. The posterior ear consists of thicker skin that is slightly more mobile. The lobule of the outer ear consists of no cartilage. Medial to the tympanic membrane is the middle ear. This area includes the tympanic cavity and 3 bony ossicles, the malleus, incus, and stapes. The middle ear also connects to the pharynx by way of the eustachian tube. The inner ear also contains the cochlea, vestibule, and semicircular canals.
The temporal bone ( Fig. 2 ) protects the middle ear and is divided into 4 distinct areas: the squamous, tympanic, mastoid, and petrous portions. The squamous portion is flat and continues toward the zygomatic process of the temporal bone. The mastoid portion contains the mastoid process and comprises the posterior aspect of the temporal bone. Medial to the mastoid process and lateral to the styloid process is the stylomastoid foramen, from which the facial nerve (cranial nerve [CN] VII) exits. The tympanic portion, inferior to the squamous region, houses the external auditory meatus. The petrous portion of the temporal bone lies on the interior of the temporal bone and encases the contents of the middle and inner ear. In addition, the petrous portion of the temporal bone is the densest bone in the human body. The internal acoustic canal is located within the petrous portion of the temporal bone and houses the facial nerve, vestibular cochlear nerve, and labyrinthine artery.
The external ear receives its blood supply from branches of the external carotid artery. These branches include the posterior auricular, superficial temporal, occipital, and maxillary (the deep auricular branch, which supplies the deep aspect of the EAC and tympanic membrane) arteries. Several nerves contribute to the innervation of the ear ( Fig. 3 ). The skin of the auricle is supplied by the greater and lesser occipital nerves (branches of the cervical plexus), the auriculotemporal nerve (branch of the trigeminal nerve), and branches of the vagus (CN X) and facial nerves for the deeper aspects of the auricle and external auditory meatus. Branches of the glossopharyngeal nerve (CN IX) may also contribute to innervation of the auricle or skin overlying the mastoid process.
Soft tissue injuries of the ear
The Advanced Trauma Life Support protocol should be followed for all patients with trauma, beginning with the primary survey and resuscitation. After initial stabilization of the patient’s injuries, if indicated, a comprehensive maxillofacial examination can proceed as part of the secondary survey. If there is a noted otologic injury, it should not be addressed until a thorough clinical and radiographic evaluation is completed. Common trauma to the external ear includes abrasions, lacerations, auricular hematomas, and partial/total avulsions.
Adequate anesthesia must be obtained before attempting any repair. For small lacerations, local anesthetic infiltration can be sufficient. However, for more complex repairs, providers should consider nerve blocks. In the past there was concern for necrosis of the overlying soft tissues and cartilage if local anesthesia with epinephrine was used; however, the literature has not supported this concern and has shown that local anesthesia with epinephrine can be used in acral areas such as the ear. Studies have shown a measurable decrease in the arterial inflow immediately following administration of local anesthetics with epinephrine, but overall perfusion of the soft tissue and cartilage are not affected. The use of epinephrine-containing local anesthetics maximizes the effectiveness and duration of the anesthetic, provides hemostasis, and serves to potentially decrease total operating time. Because the ear is innervated by several nerve branches, a ring block can be used to provide adequate anesthesia ( Fig. 4 ). The vasculature is superficial in this area, so providers should always aspirate before injection. If the superficial temporal artery is accidently punctured, firm compression should be applied to prevent the risk of hematoma formation.
After anesthesia is obtained, care should be taken to adequately clean and irrigate the wound of any foreign bodies or debris. Simple lacerations not involving the cartilage are usually closed via primary closure ( Fig. 5 ). Occasionally, irregular skin edges can be trimmed to allow better reapproximation of the wound edges. Closure can be obtained with either a fine 5-0 nonresorbable or resorbable suture. It is recommended to use resorbable sutures when repairing soft tissue injuries in children. After closure is obtained, bacitracin ointment is recommended for the first 5 days postoperatively to keep the surgical site moist and prevent eschar formation or infection.
Complex lacerations of the ear almost always involve cartilage exposure ( Fig. 6 ). Motor vehicle collisions, ballistic injuries, and animal/human bites are common causes for these injuries. The ear has a robust vascular supply, as previously mentioned, and thus even the smallest areas of attached tissue should be reapproximated if feasible. Tacking sutures should be placed with caution to avoid compromising the vascular supply. These sutures can also help with surgical/anatomic orientation during reapproximation. When repairing the cartilage, figure-of-eight sutures should be placed to prevent overlapping of the cartilaginous segments. Depending on the amount of edema or if any trauma is involving the EAC, a Xeroform packing or other similar material can be placed into the canal to help prevent stenosis. If there is any concern for a contaminated wound, prophylactic antibiotics can be prescribed to prevent perichondritis. The preferred oral antibiotic remains ciprofloxacin because it covers the main cause of perichondritis, Pseudomonas aeruginosa . Common intravenous antibiotics include Zosyn (piperacillin and tazobactam), select carbapenems, or fourth-generation cephalosporins.
Another common injury after trauma to the external ear is the auricular hematoma. Although any form of trauma can lead to an injury of this nature, wrestlers, boxers, and mixed martial artists are most commonly susceptible. The sequela of leaving this injury untreated is classically known as a cauliflower ear. Trauma caused by shearing forces to the pinna of the ear disrupts the perichondrium from the underlying cartilage. The perichondrium is responsible for supplying blood and nutrients to the cartilage. A hematoma then forms in the subperichondrial space. If untreated, the hematoma can lead to infection, necrosis, or loss of cartilage. The resulting hematoma, if not drained, stimulates new and asymmetric cartilage to form, resulting in a cauliflower ear. Treatment success is determined by timely and appropriate drainage of the hematoma. Methods such as needle aspiration or simple incision and drainage have both been successful. An 18-gauge needle is sufficient for drainage of a hematoma, ideally placed over the greatest area of fluctuance. If the patient presents greater than 6 to 8 hours after the hematoma has formed, the blood may have already started coagulating. If no blood is able to be aspirated, the procedure should transition to an incision and drainage. An incision can be made along the hematoma, large enough to provide adequate drainage. After the hematoma is evacuated and thorough irrigation has been completed, a compressive dressing should be placed to prevent dead space and allow reattachment of the perichondrium to the cartilage. A Xeroform bolster ( Fig. 7 ), cotton rolls, magnets, and silicone dressings have all been used in clinical practice with success. Quilting sutures, which pass through the external skin and the cartilage, can also serve to reattach the perichondrium. A common disadvantage is that several sutures must be placed for greatest effect. A Glasscock ear dressing can also be placed to avoid any further trauma. Repeated trauma and long-standing cauliflower ear can obstruct the EAC and interfere with hearing. In addition, reconstruction of the cauliflower ear often results in poor outcomes because of the altered blood supply and exuberant fibrocartilage. Thus, urgent treatment of an auricular hematoma is always recommended.
