Speed hump spine fractures: injury mechanism and case series.

ABSTRACT

STUDY DESIGN: Retrospective case series. OBJECTIVES: To describe an injury mechanism and a series of patients with spine fractures after passing over speed humps in a motor vehicle. SUMMARY OF BACKGROUND DATA 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.