Pedestrians injured by automobiles: relationship of age to injury type and severity

BACKGROUND: There is little research on the effect of age on the nature and severity of injuries to pedestrians struck by automobiles. STUDY DESIGN: Trauma registry study included all auto versus pedestrian trauma admissions of pedestrians injured by automobiles at an academic Level I trauma center over 10 years and 4 months. Injury Severity Score, severe body area (head, chest, abdomen, extremities) trauma with Abbreviated Injury Score >3, specific organ injuries, and mortality were calculated according to age groups (< or =14 years, 15 to 55 years, 56 to 65 years, >65 years). RESULTS: During the study period 5,838 admissions were reviewed. There were 1,136 patients (19.4%) 14 years old or less, 3,741 (64.1%) who were 15 to 55 years, 420 (7.2%) 56 to 65 years, and 541 (9.3%) older than 65 years. Overall mortality was 7.7% and ranged from 3.2% in the age group 14 years or less to 25.1% in patients over 65 years. The incidences of severe trauma (Injury Severity Score >15) in the four age groups were 11.2%, 18.7%, 23.6%, and 36.8%, respectively. The incidences of critical trauma (Injury Severity Score >30) were 2.3%, 3.9%, 5.7%, and 13.9%, respectively. The incidence of severe head and chest trauma (Abbreviated Injury Score >3) increased with age. The incidence of solid organ and hollow viscus injuries was similar in all age groups. Spinal injuries increased significantly with age and ranged from 0.4% in the pediatric group to 8.5% in the elderly group. Pelvic and tibial fractures were significantly more common in adults; femur fractures were significantly more common in the pediatric group. CONCLUSIONS: Age plays an important role in the anatomic distribution and severity of injuries and survival outcomes after pedestrian injuries.