title: Occult vertebral fractures in ankylosing spondylitis.
abstract: METHODS
  A retrospective review of patients with ankylosing spondylitis involved in a blunt trauma.
  
  
  METHODS
  Patients referred to two Level I tra uma centers.
  
  
  OBJECTIVE
  To determine the incidence and clinical sequelae in thi s patient population where vertebral injury was diagnosed on a delayed basis.
  
  
  BACKGROUND
  The ankylosed spine is at increased risk for fracture and spinal cord injury. Radiological identification of injury is more difficult than in the normal spine.
  
  
  RESULTS
  Over a 5 year period, 21 patients were identified with seven having an occult vertebral fracture not recognized as the primary injury or occurring as a second non-contiguous injury level. In these cases, delay in diagnosis of the occult injury was from 3 to 22 days. Development of secondary neurological deficits occurred in three patients.
  
  
  CONCLUSIONS
  A high index of suspicion and an appreciation of the extreme instability of a fracture in ankylosing spondylitis must be present.
authors.affiliation: Division of Orthopedic Surgery, Sunnybrook Health Science Center and The University of Toronto, Ontario, Canada.
authors.forename: J A
authors.initials: JA
authors.lastname: Finkelstein
authors.forename: J R
authors.initials: JR
authors.lastname: Chapman
authors.forename: S
authors.initials: S
authors.lastname: Mirza
mesh_terms: D000058:Accidental Falls; D000063:Accidents, Traffic; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D016103:Spinal Fractures / Q000175:diagnosis* / Q000209:etiology* / Q000601:surgery; D013167:Spondylitis, Ankylosing / Q000150:complications*; D014949:Wounds, Nonpenetrating / Q000150:complications*