title: Cervical myelopathy with retroodontoid pseudotumor caused by atlantoaxial rotatory fixation and senile tremor.
abstract: OBJECTIVE
  A rare case of retroodontoid pseudotumor caused by the combination of atlantoaxial rotatory fixation and senile tremor is reported.
  
  
  METHODS
  A 63-year-old man was treated for cervical myelopathy with retroodontoid pseudotumor caused by atlantoaxial rotatory fixation and senile tremor. He had an 18-year history of torticollis and a 7-year history of tremor. Magnetic resonance imaging revealed a retroodontoid pseudotumor compressing the spinal cord. Computed tomography showed an atlantoaxial rotatory fixation and osteoarthritis of the lateral facets. Resection of the posterior arch of the atlas and a posterior occiput-to-axis arthrodesis were performed with an autologous bone graft. His neurological condition improved, and the retroodontoid pseudotumor disappeared at 3-year follow up.
  
  
  CONCLUSIONS
  Frequent rotation of the head by the senile tremor caused friction of the lateral atlantoaxial facet with the development of osteoarthritis. This long-term mechanical stress was thought to cause the soft tissue hypertrophy around the lateral facet. Although spontaneous resolution of the pseudotumor after fixation of the unstable segment has been reported as the treatment of choice, decompression with occipitoaxial fusion was selected in the current case because the patient's neurological deficit was severe and progressive because of a remarkable canal stenosis at level C1/2.
authors.affiliation: Department of Orthopaedic Surgery, Surgical Science, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan. masahiko@is.icc.u-tokai.ac.jp
authors.forename: Masahiko
authors.initials: M
authors.lastname: Watanabe
authors.forename: Toru
authors.initials: T
authors.lastname: Iwashina
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sakai
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Joji
authors.initials: J
authors.lastname: Mochida
mesh_terms: D001268:Atlanto-Axial Joint / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D006801:Humans; D004204:Joint Dislocations / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009809:Odontoid Process / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D011859:Radiography; D012399:Rotation; D013118:Spinal Cord Diseases / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D014103:Torticollis / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery; D016896:Treatment Outcome; D014202:Tremor / Q000150:complications* / Q000473:pathology