title: Myelopathy caused by retro-odontoid disc hernia: case report.
abstract: OBJECTIVE
  Among masses in the craniovertebral junction causing severe compression of the medulla and upper cervical cord, cases of retro-odontoid disc hernia are extremely rare. We report a case of retro-odontoid disc hernia resulting in severe myelopathy.
  
  
  METHODS
  An 82-year-old man suffered from progressive tetraparesis. Although cervical radiological studies showed marked spondylotic change, no congenital malformations or traumatic lesions were identified. Magnetic resonance imaging disclosed a retro-odontoid soft tissue mass with peripheral enhancement compressing the medulla and the upper cervical cord posteriorly.
  
  
  METHODS
  The patient underwent surgery through the posterior approach. The histopathological examination of the surgical specimen revealed fibrocartilage accompanied by reactive vascular tissue; the mass was diagnosed as a retro-odontoid disc hernia.
  
  
  CONCLUSIONS
  In the differential diagnosis of mass lesions compressing the neural structures in the craniovertebral junction, retro-odontoid disc hernia, although extremely rare, should be considered to be one possibility. The posterior approach with wide laminectomies provides a good operative field from which to remove the retro-odontoid mass and is especially adequate for elderly patients, because it is less invasive than other procedures.
authors.affiliation: Department of Neurosurgery, Hamamatsu University School of Medicine, Shizuoka, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nishizawa
authors.forename: H
authors.initials: H
authors.lastname: Ryu
authors.forename: T
authors.initials: T
authors.lastname: Yokoyama
authors.forename: K
authors.initials: K
authors.lastname: Uemura
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology; D003937:Diagnosis, Differential; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000150:complications* / Q000175:diagnosis / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D009809:Odontoid Process / Q000473:pathology / Q000601:surgery; D011782:Quadriplegia / Q000209:etiology; D013117:Spinal Cord Compression / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery; D014057:Tomography, X-Ray Computed