title: Synovial cyst at the C1-C2 junction in a patient with atlantoaxial subluxation.
abstract: Synovial cysts of the cervical spine causing myelopathy are rare. The pathogenesis of these cysts is often attributed to degenerative changes of the facet joints or microtrauma. The authors report a synovial cyst at the C1-C2 junction in a patient with atlantoaxial subluxation without a congenital anomaly or inflammatory conditions. A 72-year-old man presented with a progressive right-sided myelopathy attributed to a C1-C2 synovial cyst accompanied by atlantoaxial subluxation and C3-C6 spondylosis. Magnetic resonance imaging of the cervical spine showed a large cystic mass compressing the spinal cord located at the C1-C2 junction. A C1 hemilaminectomy, complete evacuation of the cyst contents, and posterior atlantoaxial fusion were performed, and a double-door laminoplasty was also done at C3-C6. The patient showed significant improvement of paresthesia and motor weakness of the right upper and lower extremities immediately after the operation. Synovial cysts should be considered in the differential diagnosis of an extradural mass of the upper cervical spine. Posterior fusion combined with direct excision of the cyst may be the optimum treatment of a synovial cyst at the C1-C2 junction in a patient with atlantoaxial subluxation.
authors.affiliation: Department of Orthopedic Surgery, Kanebo Memorial Hospital, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Okamoto
authors.forename: Minoru
authors.initials: M
authors.lastname: Doita
authors.forename: Masaho
authors.initials: M
authors.lastname: Yoshikawa
authors.forename: Michihiko
authors.initials: M
authors.lastname: Manabe
authors.forename: Norihide
authors.initials: N
authors.lastname: Sha
authors.forename: Shinichi
authors.initials: S
authors.lastname: Yoshiya
mesh_terms: D000368:Aged; D001268:Atlanto-Axial Joint / Q000000981:diagnostic imaging*; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D004204:Joint Dislocations / Q000150:complications* / Q000175:diagnosis / Q000601:surgery; D008297:Male; D011859:Radiography; D013118:Spinal Cord Diseases / Q000209:etiology; D013581:Synovial Cyst / Q000175:diagnosis* / Q000209:etiology* / Q000601:surgery; D016896:Treatment Outcome