title: Aneurysmal bone cyst of the second cervical vertebrae causing multilevel upper cervical instability.
abstract: OBJECTIVE
  Aneurysmal bone cyst (ABC) is a rare expansile osteolytic lesion of bone comprising proliferating vascular tissue lining blood-filled cystic cavities. ABCs occur most frequently in patients under age 20 and are uncommon after 30 years of age. Three to 20% of cases occur in the spine, and upper cervical involvement is rare. Lesions may grow rapidly and attain considerable size. When involving the spine, ABCs may result in instability and neurologic compromise, making prompt diagnosis and treatment imperative. We present a report of a 6-year-old child with an ABC of the second cervical vertebrae causing atlantoaxial and C2-C3 instability, treated successfully with curettage, decompression, and anterior and posterior arthrodesis with posterior instrumentation.
  
  
  METHODS
  The patient underwent a staged procedure consisting of posterior instrumentation from occiput to C4 and curettage of the lesion followed by anterior cervical discectomy and fusion of C2-C4. The diagnosis, surgical treatment, and outcome of the case are described and relevant literature reviewed.
  
  
  RESULTS
  The patient sustained no lasting neurologic deficits and was disease-free at 3 years of follow-up.
  
  
  CONCLUSIONS
  ABC is a rare but potentially devastating cause of upper cervical spine instability. Prompt detection and treatment with curettage, decompression, and fusion can produce a satisfactory result and prevent spinal cord injury.
authors.affiliation: Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI, USA. Levind01@yahoo.com
authors.forename: David A
authors.initials: DA
authors.lastname: Levin
authors.forename: Robert N
authors.initials: RN
authors.lastname: Hensinger
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Graziano
mesh_terms: D001268:Atlanto-Axial Joint / Q000601:surgery; D017824:Bone Cysts, Aneurysmal / Q000150:complications* / Q000601:surgery; D002574:Cervical Vertebrae / Q000601:surgery; D002648:Child; D019299:Decompression, Surgical; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000209:etiology*; D013122:Spinal Diseases / Q000150:complications* / Q000601:surgery; D013123:Spinal Fusion