title: Speed hump spine fractures: injury mechanism and case series.
abstract: METHODS
  Retrospective case series.
  
  
  OBJECTIVE
  To describe an injury mechanism and a series of patients with spine fractures after passing over speed humps in a motor vehicle.
  
  
  BACKGROUND
  The use of speed humps as an effective measure to reduce the rate of traffic accidents is still a matter of discussion. Furthermore, their use in mass transport routes may cause spine injuries among passengers in motor vehicles.
  
  
  METHODS
  Review of the database in our medical records, identifying all the patients with spine fractures that occurred after passing over speed humps while in a motor vehicle, from January 1, 1997 to April 30, 2008 in the Hospital del Trabajador de Santiago, Chile.
  
  
  RESULTS
  Of a sample of 46 patients with 52 fractures-none of them with neurologic impairment-37 female patients (80.4%) and 9 male patients (19.6%) with an average age of 48.5 years (16 to 70 y), 67.4% (31 of 46) presented comorbidities. Six patients presented 2 spine fractures, all of them at adjacent levels. Forty-four individuals (95.7%) were injured in a bus: 42 of 44 patients (95.5%) were seated on the last row, whereas the remaining 2 patients were bus drivers. All patients had type A Association for Osteosynthesis/Association for the Study of Internal Fixation fractures, 30/52 (57.7%) subtype A1 and 20/52 (38.5%) subtype A3. L1 was the most frequently fractured vertebra (23/52, 44.2%), followed by T12 (11/52, 21.2%). Ten patients (21.7%) required surgical treatment. The average time out of work was 104.3 days; 3 patients (6.5%) received workers' compensation for chronic lumbar pain. The mean follow-up time was 78.6 months (24 to 159).
  
  
  CONCLUSIONS
  Seating in a motor vehicle, particularly on the last row in a bus, as it passes over a speed hump may cause severe traumatic spine injuries. These fractures occur more frequently at the thoracolumbar junction and treatment may require surgery.
authors.affiliation: Spine Surgery Unit, Department of Orthopedics, Hospital del Trabajador de Santiago, Providencia, Santiago, Chile. mmunjin@hts.cl
authors.forename: Milan A
authors.initials: MA
authors.lastname: Munjin
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Zamorano
authors.forename: Bartolomé
authors.initials: B
authors.lastname: Marré
authors.forename: Francisco
authors.initials: F
authors.lastname: Ilabaca
authors.forename: Vicente
authors.initials: V
authors.lastname: Ballesteros
authors.forename: Celmira
authors.initials: C
authors.lastname: Martínez
authors.forename: Ratko
authors.initials: R
authors.lastname: Yurac
authors.forename: Alejandro
authors.initials: A
authors.lastname: Urzúa
authors.forename: Miguel
authors.initials: M
authors.lastname: Lecaros
authors.forename: José
authors.initials: J
authors.lastname: Fleiderman
authors.forename: Nicolás
authors.initials: N
authors.lastname: García
mesh_terms: D000063:Accidents, Traffic; D000328:Adult; D000368:Aged; D001334:Automobile Driving; D002677:Chile; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017116:Low Back Pain / Q000209:etiology* / Q000601:surgery; D008159:Lumbar Vertebrae / Q000293:injuries*; D008297:Male; D008875:Middle Aged; D016103:Spinal Fractures / Q000209:etiology* / Q000601:surgery; D013904:Thoracic Vertebrae / Q000293:injuries*; D014942:Workers' Compensation; D017132:Workplace