Patterns of spinal cord injury in automobiles versus motorcycles and bicycles

Study design: Retrospective case series. Objectives: To examine the patterns and relative rates of occurrence of spinal cord injury (SCI) in automobiles compared to motorcycles and bicycles. Setting: Los Angeles County, California. Methods: A retrospective chart review of SCI consults at Rancho Los Amigos National Rehabilitation Center in Los Angeles County, California between 2003 and 2013 were selected and screened for a mechanism of injury involving a vehicular accident. Chart review was performed to determine neurological levels and extent of impairment, which were graded according to the International Standards for Neurological Classification of Spinal Cord Injury. Results: We identified 398 cases of SCI from 2003 to 2013 that fit the inclusion criteria. Overall, the relative percentages of ASIA impairment scale (AIS) A/B/C/D did not differ statistically across automobiles, motorcycles, or bicycles. When stratified by spinal region, motorcycles had a higher percentage of thoracic SCIs compared to automobiles. Automobiles resulted in more cervical SCIs with few injuries in the lumbar region. Bicycle patterns followed automobiles, not motorcycles. Thoracic SCIs were more likely graded motor complete than cervical or lumbar injuries, regardless of the mechanism. Conclusions: Automobile, motorcycle, and bicycle related SCIs occur primarily in the cervicothoracic region. SCIs due to motorcycle accidents have a higher predilection for the thoracic region, and there is a statistically higher percentage of motor complete injuries. A higher percentage of cervical SCIs occur as a result of automobile and bicycle accidents. Extrapolations from motor vehicle usage data suggest that the relative rate of occurrence of SCI for motorcycles is higher than for automobiles.