Objective: This study investigated the incidence of abdominal injuries in frontal crashes by occupant age and seating position. It determined the risk for abdominal injury (AIS 2+) by organ and injury source.
Methods: 1997-2015 NASS-CDS was analyzed to estimate the occurrence of abdominal injuries in non-ejected, belted occupants involved in frontal crashes. Vehicles were included with 1997+ model year (MY). The annual incidence and rate for different types of abdominal injury were estimated with standard errors. The sources for abdominal injury were determined.
Results: 77.8% of occupants were drivers, 16.7% were right-front passengers and 5.4% were rear passengers. Rear passengers accounted for 77.1% of 8-11 year old (yo) and 17.2% of 12-17 yo group. The risk for moderate abdominal injury (MAIS 2 + abdo) was 0.30% ± 0.053% in drivers, 0.32% ± 0.086% in right-front passengers and 0.38% ± 0.063% in rear occupants. The risk of MAIS 2 + abdo was highest at 0.76% ± 0.30% in the 60-84 yo group for right-front passengers and in the 85+ yo group and 8-11 yo children for rear passengers. The liver and spleen had the highest abdominal injury risk in drivers, the spleen in right-front passengers and the digestive system in rear passengers. The leading source for injury was the seatbelt at 38.6% in the drivers, 73.9% in right-front passenger and 96.2% in rear passengers. The NASS-CDS case review identified lap-belt loading on the abdomen and improper seatbelt use as injury mechanisms for rear seated children.
Conclusions: The risk of abdominal injury was high in lap-shoulder belted 8-11 yo children and 60+ yo adults in the rear in frontal crashes. There was an association between abdominal injury and the seatbelt.