Crashes and Car Accidents

Crashes and Car Accidents

Injury Differences Between Small and Large
Overlap Frontal Crashes-  Crashes and Car Accidents

Injury Differences Between Small and Large Overlap Frontal Crashes. 55th Annual

Crashes and Car Accidents
AAAM Conference. Paris, France; 2011: 147-157
Hallman JJ, Yoganandan N, Pintar FA & Maiman DJ.

Because small overlap impacts have recently emerged as a crash mode posing great
injury risk to occupants, a detailed analysis of US crash data was conducted using the
NASS/CDS and CIREN databases. Frontal crashes were subcategorized into small
overlap impact (SOI) and large overlap impact (LOI) using crash and crush
characteristics from the datasets.
Injuries to head, spine, chest, hip and pelvis, and lower extremities were parsed and
compared between crash types. MAIS 3+ occupants in NASS/CDS and CIREN
demonstrated increased incidence of head, chest, spine, and hip/pelvis injuries in SOI
compared to LOI. In NASS/CDS, subgaleal hematoma represented 48.6% of SOI head
injury codes but 27.6% in LOI.

Crashes and Car Accidents
Cervical spine posterior element fractures also represented greater proportions of SOI
spine injuries (e.g., facet fractures: 27.8 vs. 14.0%), and proximal femur fractures
represented a greater proportion of hip/pelvis injuries (e.g., intertrochanteric fracture:
32.5 vs. 11.8%). Tarsal/metatarsal fractures were a lesser proportion of lower extremity
injuries in SOI compared to LOI. Occupant contact points inducing these injuries were
observed in CIREN cases in some instances without compartment intrusion. These
injuries suggest the substantial role of occupant kinematics in SOI which may induce
suboptimal occupant restraint interaction.
In low speed car crashes, it is imperative to evaluate facet joint injuries.
Yoganandan et al. (1998) Yoganandan et al. (1299), conducting further research on
cervical spine specimens, applied reflective targets to adjacent facet joints to track facet
motion during whiplash using high speed video. They commented that, “Neck injuries
secondary to whiplash during rear end vehicular crashes have become a national and
international problem. They often result in no discernable radiographic trauma.
In contrast, soft tissue damage such as excessive deformation is an expected outcome of
these loading sequelae,” and proposed that compression and sliding motions of the facet
joints might lead to joint fiber excitation which could be productive of pain, while the
head lag portion would allow head translations producing soft tissue injuries resulting
in occipital headaches.

Crashes and Car Accidents
Panjabi and co-workers (1182) conducted simulated crash tests using human cadaver
necks with surrogate heads. This paper is one of several that resulted from this single set
of experiments, and it is clear from reading them that more will be forthcoming. In these
tests, the authors dissected eight cadaver cervical spines, removing the skull and
musculature, but taking care not to damage any of the ligamentous structures. They
used a metal surrogate head in place of the cadavers’ heads because the brains would
have had to have been removed because of the fact that the experiments covered several
days’ time. Removing the brain, of course, changes the head’s mass and center of
gravity, so the surrogate head was matched for mass and center of gravity. The spines
were fixed in quick setting epoxy.