High-Speed X-Ray Assessment of the Bony Kinematics of the Cervical Spine During Frontal Impacts

摘要

The aim of this study was to assess the feasibility of using a high-speed x-ray system (capable of 1000 frames/sec) to evaluate the bony kinematics of postmortem human surrogate (PMHS) cervical spines at real-world speeds during frontal impact. Whole-body frontal impact sled tests were performed on two fresh PMHS specimens. Screws were inserted into the tips of the spinal processes to optimize contrast on the high-speed cine x-ray. Head, T1 and sternum accelerations, as well as shoulder, and lap belt forces were recorded. Vertebral motion was captured using a modified mobile c arm x-ray system, and an image intensifier linked to a high-speed camera (Kodak motion corder analyzer, model SR 1000C, Kodak, San Diego, CA, USA) The variable parameters for the tests were camera frame rate and sled velocity. Tests were performed with delta-V's (Dv) of approximately 15 kph (8G) and 21 kph (10G). Cine x-rays of the tests were recorded at 250, 500 and 1000 frames/sec. Motion tracking analysis of the bony elements of the cervical spine was performed. Only tests recorded a 250 frames/sec produced high enough quality images to perform motion analysis. The results show high-speed cine x-ray can be used to directly visualize the bony skeleton, for the assessment of skeletal kinematics during impact. Analysis of bony kinematics using high-speed cine x-ray reduces errors caused by extrapolating data from external surface makers. Additionally, the system also offers the potential for detecting the site at which fractures originate. It also allows visualization of the timing of fractures, and the order they occur in. Further research and testing is required to optimize the use of the system, to increase the field of view and improve image quality at the highest frame rates (> 500 frames/sec).