Dynamic vertebral artery elongation during frontal and side impacts

Abstract Background context Elongation-induced vertebral artery (VA) injury has been hypothesized to occur during nonphysiological coupled head motions during automobile impacts. Although previous work has investigated VA elongation during head-turned and head-forward rear impacts, no studies have performed similar investigations for frontal or side impacts. Purpose The present study quantified dynamic VA elongations during simulated frontal and side automotive collisions, and compared these data with corresponding physiological limits. Study design/setting In vitro biomechanical study of dynamic VA elongation during simulated impacts. Methods A biofidelic whole cervical spine model with muscle force replication and surrogate head underwent simulated frontal impacts (n=6) of 4, 6, 8, and 10 g or left side impacts (n=6) of 3.5, 5, 6.5, and 8 g. Results Average (SD) maximum physiological VA elongation was 7.1 (3.2) mm, measured during intact flexibility testing. Average peak dynamic elongation of right VA during left side impact, up to 17.4 (2.6) mm, was significantly greater (p Conclusions Elongation-induced VA injury is more likely to occur during side impact as compared with frontal impact.