Date of Award

1-5-2009

Document Type

Thesis

Degree Name

Medical Doctor (MD)

First Advisor

Paul Ivancic

Abstract

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-forward rear impacts, no studies have performed similar investigations for head-turned rear, frontal, or side impacts. The present study comprehensively quantifies dynamic VA elongations during simulated head-forward rear, head-turned rear, frontal, and side impact automotive collisions, and compares these data among impact configurations and with corresponding physiological limits. 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 head-forward rear (n=6), head-turned rear (n=6), and left side (n=6) impacts of and 3.5, 5, 6.5, and 8 g. Significant increases (P<0.05) in average (SD) peak dynamic VA elongation above physiological of up to 30.5 (2.6) mm during head-turned rear impact and 17.4 (2.6) mm during side impact were observed beginning at 5 g and 6.5 g, respectively. Highest peak elongation of 5.8 (2.1) mm during head-forward rear impact and 2.5 (2.4) mm during frontal impact did not exceed physiological limit. The times of occurrence of peak VA elongation were earlier and rates later during head-turned rear and side impact vs. head-forward rear and frontal impact. Results indicate that head-turned rear and side impacts may cause elongation-induced VA injury leading to chronic symptoms of vascular insufficiency reported by whiplash patients. Elongation-induced VA injury during head-forward rear and frontal impacts is unlikely.

Comments

This thesis is restricted to Yale network users only. This thesis is permanently embargoed from public release.

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