Ear and Temporal Bone Trauma

2 Otology

2.1 Otologic Emergencies .1 Sudden Hearing Loss.1 Sudden Hearing Loss

2.1.2 Ear and Temporal Bone Trauma

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Key Features

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Outcome and Follow-Up

Follow-up audiograms to assess for recovery are obtained, usually at 2 to 3 weeks following initiation of treatment. The natural history of idiopathic sudden SNHL is that two-thirds of patients should experience some recovery without treatment, often within 2 weeks. Less-severe initial loss, shorter duration of loss, and early treatment are associated with better recovery. The presence of vertigo is associated with poorer prognosis.

Auditory rehabilitation in patients who fail to recover is important, especially in children.

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ICD-9 Code

388.2 Sudden hearing loss, unspecified

Epidemiology

Overall, between 14 and 22% of skull fractures involve the temporal bone.

These are often associated with other serious injuries. Traumatic tympanic membrane perforations have been estimated to occur at an annual incidence of 1.4 per 100,000 persons. Lacerations, avulsions, hematomas, and thermal injuries to the auricle are common.

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Clinical

Signs and Symptoms

Symptoms and signs depend on the type and extent of injury.

Auricular Injury

Blunt injury may result in local pain and swelling with auricular hematoma.

Lacerations and avulsions will present with local findings. Burns to the auricle may appear mild or full thickness; underlying cartilage viability is the critical concern. The auricle is a common site of frostbite injury, which may present as a spectrum of symptoms over several weeks—from clear blistering, hemor- rhagic blisters, a dry insensate wound, to blackened tissue demarcation.

Penetrating Trauma or Perforations

Foreign body, instrumentation, blunt injury, acoustic trauma, and barotrauma may all cause traumatic tympanic membrane rupture as well as middle or inner ear damage. Patients may present with pain, hearing loss, dizziness, or facial paresis.

Temporal Bone Fracture

This is associated with severe traumatic head injury and the patient will present as such, requiring resuscitation, stabilization and multiteam care.

Victims may present with Battle’s sign (mastoid bruise), raccoon eyes (periorbital bruising), otorrhea, hearing loss, nystagmus, and other cranial neuropathies. Fracture is classified by CT scan with respect to the long axis of the petrous pyramid: a transverse fracture crosses this axis (10–20% of fractures); a longitudinal fracture is oriented along this axis; fractures are most commonly mixed (Fig. 2.5).

Differential Diagnosis

The differential diagnosis may include soft tissue injury, an auricular hematoma, a cartilage injury, a tympanic membrane perforation, an ossicular disruption, a perilymph fistula, an inner ear injury, a temporal bone fracture, and a facial nerve injury.

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Evaluation

Physical Exam

The examination should include a full head and neck exam, paying special attention to cranial nerves. In a trauma patient with severe head injury or multisystem injury, standard trauma protocol and resuscitation are performed. Life-threatening injuries (cervical spine trauma, intracranial injury, etc.) must be stabilized prior to evaluation of a temporal bone injury. With severe injuries requiring intubation and other treatment,

an initial assessment of facial nerve function is important. Cleaning and examination of the ear promotes the assessment of the injuries. Initially, hearing can be assessed with 512-Hz tuning fork. Presence and type of nystagmus should be noted. When stable, temporal bone CT scanning is performed.

In the patient with more limited injury, a more focused exam is feasible.

Foreign body or penetrating injuries must be evaluated under the otomi- croscope. In uncooperative children, there should be a low threshold for exam under anesthesia. Ear canal injuries can be cleaned and stented if circumferential. Traumatic perforations may require surgical exploration if located in the posterosuperior quadrant and associated with severe vertigo.

However, most perforations are anteroinferior and can be observed. Avoid pneumatic otoscopy.

Soft tissue injuries isolated to the auricle are treated with focused exam and emergency care. Exposed cartilage and hematoma must be recognized and treated promptly.

Imaging

High-resolution CT scanning of the temporal bone is the most useful imaging study for temporal bone trauma. Angiography is indicated with gunshot wounds to rule out vascular injury.

Fig. 2.5 Temporal bone fractures: a typical longitudinal temporal bone fracture (left) and transverse temporal bone fracture (right). (From Probst R, Grevers G, Iro H. Basic Otorhinolaryngology: A Step-by-Step Learning Guide. Stuttgart/New York: Thieme; 2006:303.)

Other Tests

Perform an audiologic assessment as soon as feasible. Electrophysiologic testing of the facial nerve in the setting of traumatic paralysis may be helpful in terms of predicting recovery and guiding treatment decisions.

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Treatment Options

Soft Tissue Injuries

Auricular lacerations must be cleaned thoroughly. Cartilage may be reap- proximated. When possible, soft tissue should be closed over exposed cartilage. If tissue is devitalized, wet-to-dry dressing coverage can be provided and surgical reconstruction planned in a delayed fashion. Antibiotics are prescribed, and Pseudomonas coverage is required.

Auricular hematomas must be drained to prevent a cauliflower defor- mity. To prevent reaccumulation, a pressure bolster is applied. Dental roles or rolled Xeroform (Kendall Company, Mansfield, MA) are placed on the anterior and posterior surface of the auricle and secured with 2–0 nylon in a through-and-through mattress stitch for 5 days. Antibiotics are prescribed.

Auricular burns are treated with mafenide topically. This may penetrate eschar and help to prevent cartilage loss. Infected cartilage is débrided. With a frostbite injury, avoidance of thawing and refreezing is critical. Injured areas are rapidly rewarmed and patients may benefit from ibuprofen.

Ongoing local wound care is required as the injury demarcates.

Attempt at surgical reattachment of avulsions should be performed.

There is a high failure rate, requiring delayed débridement and discussion of reconstructive options. Most animal bites are thoroughly irrigated, closed, and treated with oral antibiotics. Management of human bites remains controversial. Débridement, irrigation, intravenous (IV) antibiotics for 48 hours and delayed repair is advocated by some; others treat human auricular bite wounds with irrigation, immediate closure, and oral antibiotics.

Penetrating Trauma/Perforations

Ear canal lacerations should be suctioned and cleaned under the microscope.

If circumferential, stenting with Oto-Wick (Medtronic Xomed, Inc., Jackson- ville, FL) or Gelfoam (Pfizer Pharmaceuticals, New York, NY) for 10 days may be required to prevent stenosis. Antibiotic and steroid drops are prescribed.

Traumatic perforations in the posterosuperior quadrant with symptom- atic vertigo should undergo exploratory tympanotomy due to possible stapes dislocation. At surgery, unstable bone fragments are removed and the oval window is grafted; prosthesis placement is controversial.

Traumatic perforation in other locations can be treated conservatively.

Antibiotic steroid drops are prescribed, dry ear precautions observed, nose- blowing avoided, and follow-up exams planned. Vestibular symptoms are treated with antiemetics and rest. Approximately 90% of small perforations heal spontaneously. Large perforations or an accompanying infection may complicate healing and eventually require surgical repair.

Temporal Bone Fracture

If there is no facial nerve injury, from an otologic standpoint the fracture may be handled conservatively. Local wound care and follow-up audiograms are necessary. However, patients often require neurosurgical intervention for other injuries. If there is complete facial nerve paralysis, this may require surgical exploration, depending on the nature of the injury. Gunshot wounds may involve widespread injury, carrying a high incidence of severe vascular injury and high mortality rate. Cerebrospinal fluid (CSF) otorrhea or rhinor- rhea may require surgical repair via a neurosurgical or mastoid approach.

Injuries with CSF otorrhea not requiring neurosurgical repair may be observed with conservative measures; a high percentage spontaneously stop.

Antibiotic prophylaxis is controversial. Audiometry at 3 months should be performed to follow conductive hearing loss. Persistent conductive loss may require exploratory tympanotomy. Vestibular dysfunction is treated with rest and antiemetics; follow-up vestibular testing is performed.

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Outcome and Follow-Up

For temporal bone injuries involving hearing loss, follow-up audiograms are required, as discussed above. Most traumatic perforations heal spontaneously but should be reassessed at 3 months. Benign paroxysmal peripheral vertigo is common following temporal bone injuries, and is managed with canalith repositioning exercises. For patients without hearing recovery, auditory rehabilitation options should be offered, ranging from a conventional hearing aid, a bone-anchored hearing aid, to possible cochlear implantation.

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ICD-9 Code

801 Fracture of base of skull

2 Otology

2.1 Otologic Emergencies .1 Sudden Hearing Loss.1 Sudden Hearing Loss

2.1.2 Ear and Temporal Bone Trauma

Key Features

Outcome and Follow-Up

ICD-9 Code

Further Reading

Epidemiology

Clinical

Evaluation

Treatment Options

Outcome and Follow-Up

ICD-9 Code

Further Reading