title: Malpositioned spinal instrument as a possible cause of superficial siderosis.
abstract: METHODS
  Case report.
  
  
  OBJECTIVE
  To report a patient with superficial siderosis as a complication after posterior fixation surgery for odontoid fracture.
  
  
  METHODS
  Department of Neurosurgery, Hokkaido University, Japan.
  
  
  METHODS
  A 36-year-old man had undergone C1-C2 posterior fixation using lamina hooks for an odontoid fracture in 1997. In 2003, he presented with hearing loss and ataxia; and in 2006, a diagnosis of superficial siderosis was made and spinal instrument malpositioning was detected.
  
  
  RESULTS
  The malpositioned instrument, suspected as the cause of superficial siderosis, was removed.
  
  
  CONCLUSIONS
  Superficial siderosis of the central nervous system is rare; it results in progressive hearing loss, cerebellar ataxia and pyramidal sign. Chronic hemorrhage in the subarachnoid space precipitates hemosiderin around the cerebellum and brainstem resulting in neurological symptoms. Recurrent hemorrhage and cervical root pathology, for example, root avulsion, are factors; the symptoms worsen gradually and result in hemostasis. Superficial siderosis because of complications from spinal instrumentation surgery is extremely rare. If the instrument is malpositioned in the subarachnoid space, we suggest its removal.
authors.affiliation: Department of Neurosurgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan. taoya@sirius.ocn.ne.jp
authors.forename: T
authors.initials: T
authors.lastname: Aoyama
authors.forename: K
authors.initials: K
authors.lastname: Hida
authors.forename: S
authors.initials: S
authors.lastname: Yano
authors.forename: M
authors.initials: M
authors.lastname: Kawabori
authors.forename: M
authors.initials: M
authors.lastname: Iwasaki
authors.forename: Y
authors.initials: Y
authors.lastname: Iwasaki