Temporal bone fracture.
Otoscopy of the left ear revealed a longitudinal fracture of the bony canal with a diastasis that was covered with thin epithelium (figure 1). The tympanic membrane was distorted but intact. The long process of the incus appeared to be rotated superiorly and laterally, and the lenticular process was tenting the tympanic membrane. Audiometry demonstrated a left-sided conductive hearing loss that was mild in the lower frequencies and down-sloping to severe in the higher frequencies. High-resolution computed tomography (HRCT) showed subluxation of the left incus body relative to the head of the malleus (figure 2).
A left postauricular type III tympanoplasty with an incus interposition graft and canaloplasty was performed. The longitudinal temporal bone fracture that extended down the length of the bony canal could be seen dearly. In addition, it was noted that the incus was dislocated, with the long process projecting laterally and separated from the head of the stapes, with only a fibrous band connecting the drum to the stapes capitulum. The malleus and the stapes were mobile and intact.
Temporal bone fractures most commonly occur as a result of motor vehicle accidents, assaults, falls, gunshot wounds, and sports accidents. (1) They are generally classified as either longitudinal or transverse and as either otic-capsule-sparing or otic-capsule-involving. Longitudinal fractures are more common. They are so named because they run parallel to the long axis of the petrous pyramid. They are often caused by a lateral blow to the head, and they tend to cause damage to the external auditory canal and tympanic membrane. Complications may include blood in the external auditory canal, hemotympanum, ossicular chain disruption and, less commonly, facial nerve paralysis.
Transverse fractures account for approximately 20% of temporal bone fractures. They occur secondary to frontal or occipital head trauma, and they run perpendicular to the petrous pyramid. They can manifest as sensorineural hearing loss secondary to otic capsule involvement and as vertigo; facial nerve damage is possible. (2)
Ossicular discontinuity, as occurred in our patient, is one of the many causes of conductive hearing loss in patients with temporal bone fractures. Disarticulation of the incudostapedial joint and/or incudomalleolar joint may occur, so it is extremely important to carefully examine both joints in order to achieve the best potential outcome for hearing. (3)
(1.) Johnson F, Semaan MT, Megerian CA. Temporal bone fracture: Evaluation and management in the modern era. Otolaryngol Clin North Am 2008;41(3):597-618, x.
(2.) Little SC, Kesser BW. Radiographic classification of temporal bone fractures: Clinical predictability using a new system. Arch Otolaryngol Head Neck Surg 2006;132(12):1300-4.
(3.) Yetiser S, Hidir Y, Birkent H, et al. Traumatic ossicular dislocations: Etiology and management. Am J Otolaryngol 2008;29(1):31-6.
Danielle M. Blake, BA; Senja Tomovic, MD; Robert W. Jyung, MD
From the Department of Otolaryngology-Head and Neck Surgery, Rutgers New Jersey Medical School, Newark.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||OTOSCOPIC CLINIC|
|Author:||Blake, Danielle M.; Tomovic, Senja; Jyung, Robert W.|
|Publication:||Ear, Nose and Throat Journal|
|Date:||Jan 1, 2014|
|Previous Article:||Money: the elephant in the resident's room.|
|Next Article:||Unusual rhabdomyolysis of the masticator space.|