title: Cranial nerve injury after minor head trauma.
abstract: OBJECTIVE
  There are no specific studies about cranial nerve (CN) injury following mild head trauma (Glasgow Coma Scale Score 14-15) in the literature. The aim of this analysis was to document the incidence of CN injury after mild head trauma and to correlate the initial CT findings with the final outcome 1 year after injury.
  
  
  METHODS
  The authors studied 49 consecutive patients affected by minor head trauma and CN lesions between January 2000 and January 2006. Detailed clinical and neurological examinations as well as CT studies using brain and bone windows were performed in all patients. Based on the CT findings the authors distinguished 3 types of traumatic injury: no lesion, skull base fracture, and other CT abnormalities. Patients were followed up for 1 year after head injury. The authors distinguished 3 grades of clinical recovery from CN palsy: no recovery, partial recovery, and complete recovery.
  
  
  RESULTS
  Posttraumatic single nerve palsy was observed in 38 patients (77.6%), and multiple nerve injuries were observed in 11 (22.4%). Cranial nerves were affected in 62 cases. The most affected CN was the olfactory nerve (CN I), followed by the facial nerve (CN VII) and the oculomotor nerves (CNs III, IV, and VI). When more than 1 CN was involved, the most frequent association was between CNs VII and VIII. One year after head trauma, a CN deficit was present in 26 (81.2%) of the 32 cases with a skull base fracture, 12 (60%) of 20 cases with other CT abnormalities, and 3 (30%) of 10 cases without CT abnormalities.
  
  
  CONCLUSIONS
  Trivial head trauma that causes a minor head injury (Glasgow Coma Scale Score 14-15) can result in CN palsies with a similar distribution to moderate or severe head injuries. The CNs associated with the highest incidence of palsy in this study were the olfactory, facial, and oculomotor nerves. The trigeminal and lower CNs were rarely damaged. Oculomotor nerve injury can have a good prognosis, with a greater chance of recovery if no lesion is demonstrated on the initial CT scan.
authors.affiliation: Department of Neurosurgery, Bellvitge University Hospital, L'Hospitalet de Llobregat, Barcelona, Spain. jandrocoello@gmail.com
authors.forename: Alejandro Fernández
authors.initials: AF
authors.lastname: Coello
authors.forename: Andreu Gabarrós
authors.initials: AG
authors.lastname: Canals
authors.forename: Juan Martino
authors.initials: JM
authors.lastname: Gonzalez
authors.forename: Juan José Acebes
authors.initials: JJ
authors.lastname: Martín
mesh_terms: D000328:Adult; D000368:Aged; D003389:Cranial Nerve Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology; D020209:Cranial Nerve Injuries / Q000000981:diagnostic imaging / Q000453:epidemiology*; D003391:Cranial Nerves / Q000000981:diagnostic imaging; D006259:Craniocerebral Trauma / Q000000981:diagnostic imaging / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D020127:Recovery of Function; D012720:Severity of Illness Index; D019291:Skull Base / Q000000981:diagnostic imaging / Q000293:injuries; D012887:Skull Fractures / Q000000981:diagnostic imaging / Q000453:epidemiology; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D055815:Young Adult