title: The Rates and Clinical Characteristics of Pneumolabyrinth in Temporal Bone Fracture.
abstract: BACKGROUND
  Pneumolabyrinth is a rare inner ear clinical manifestation. To date, only about 50 cases have been reported—all as case reports. Consequently, the rate and clinical characteristics of pneumolabyrinth have not been evaluated.
  
  
  METHODS
  Of the 38, 568 patients who visited our emergency department for head trauma, 466 underwent temporal bone computed tomography (CT). One hundred seventy-five patients had temporal bone fracture (13 bilateral temporal bone fractures; 188 ears with temporal bone fractures), and 14 patients had pneumolabyrinth (15 ears with pneumolabyrinth; 1 bilateral case). A retrospective review of their medical records and radiologic findings was performed. Temporal bone fractures were classified by two different systems: the traditional classification and an otic capsule-based classification.
  
  
  RESULTS
  Pneumolabyrinth occurred in 8.0% of all temporal bone fractures, 4.0% of longitudinal temporal bone fractures, 16.1% of transverse or mixed temporal bone fractures, and 48.4% of otic capsule-violating temporal bone fractures. In all cases, pneumolabyrinth was found on CT, which was performed within 3 days, but not on follow-up CT performed 5 days or longer after head trauma. All patients complained of hearing loss and dizziness. Hearing in most patients (83.3%) did not improve, whereas dizziness improved in 91.7% of patients. Air was located only in the vestibule or semicircular canal in 53.3% and in the vestibular or semicircular canal and cochlea in 46.6% of ears with pneumolabyrinth. The initial hearing threshold and recovery rate using pure-tone audiometry were not different according to the air location in the inner ear.
  
  
  CONCLUSIONS
  Pneumolabyrinth was more common than expected; we believe that the timing of evaluation affects its rarity. Pneumolabyrinth was detected in nearly 50% of patients with otic capsule-violating temporal bone fractures when CT scanning was performed early after trauma.
authors.affiliation: *Department of Otorhinolaryngology-Head and Neck Surgery and †Interdisciplinary Program-Molecular Medicine, Hallym University College of Medicine, Chuncheon, Republic of Korea.
authors.forename: Hyo Geun
authors.initials: HG
authors.lastname: Choi
authors.forename: Hyo-Jeong
authors.initials: HJ
authors.lastname: Lee
authors.forename: Joong Seob
authors.initials: JS
authors.lastname: Lee
authors.forename: Dong Hyun
authors.initials: DH
authors.lastname: Kim
authors.forename: Sung Kwang
authors.initials: SK
authors.lastname: Hong
authors.forename: Bumjung
authors.initials: B
authors.lastname: Park
authors.forename: Si Whan
authors.initials: SW
authors.lastname: Kim
authors.forename: Ja Hee
authors.initials: JH
authors.lastname: Kim
authors.forename: Hyung-Jong
authors.initials: HJ
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold; D002648:Child; D003051:Cochlea / Q000000981:diagnostic imaging; D006259:Craniocerebral Trauma / Q000150:complications / Q000473:pathology; D004244:Dizziness / Q000209:etiology; D007758:Ear, Inner / Q000000981:diagnostic imaging*; D005260:Female; D034381:Hearing Loss / Q000209:etiology; D006801:Humans; D007759:Labyrinth Diseases / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000209:etiology; D008297:Male; D008875:Middle Aged; D012665:Semicircular Canals / Q000000981:diagnostic imaging; D012887:Skull Fractures / Q000150:complications* / Q000000981:diagnostic imaging*; D013701:Temporal Bone / Q000000981:diagnostic imaging* / Q000293:injuries*; D014057:Tomography, X-Ray Computed; D014722:Vestibule, Labyrinth / Q000000981:diagnostic imaging; D055815:Young Adult