To simulate horizontally aligned head-first impacts with initial head protrusion using a human cadaveric neck model and to determine biomechanical responses, injuries, and injury severity.
Head-first impacts with initial head protrusion were simulated at 2.4 m/s using a human cadaver neck model (n = 10) mounted horizontally to a torso-equivalent mass on a sled and carrying a surrogate head. Macroscopic neck injuries were determined, and ligamentous injuries were quantified using fluoroscopy and visual inspection after the impacts. Representative time-history responses for injured specimens were determined during impact using load cell data and analyses of high-speed video.
Biomechanics research laboratory.
Cervical spines of 10 human cadavers.
Injury severity at the middle and lower cervical spine was statistically compared using a 2-sample t test (P < 0.05).
Neck buckling consisted of hyperflexion at C6/7 and C7/T1 and hyperextension at superior spinal levels. Noncontiguous neck injuries included forward dislocation at C7/T1, spinous process fracture and compression–extension injuries at the middle cervical spine, and atlas and odontoid fractures. Ligamentous injury severity at C7/T1 was significantly greater than at the middle cervical spine.
Distinct injury mechanisms were observed throughout the neck, consisting of extension–compression and posterior shear at the upper and middle cervical spine and flexion–compression and anterior shear at C6/7 and C7/T1. Our experimental results highlight the importance of clinical awareness of potential noncontiguous cervical spine injuries due to head-first sports impacts.
Biomechanics Research Laboratory, Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, Connecticut.
Corresponding Author: Paul C. Ivancic, PhD, Biomechanics Research Laboratory, Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, 333 Cedar St, PO Box 208071, New Haven, CT 06520-8071 (email@example.com).
Supported by grant 5R01CE001257 from the Centers for Disease Control and Prevention, Atlanta, Georgia, and a gift to Yale University from Aspen Medical Products, Inc, Irvine, California.
The author reports no conflicts of interest.
Received May 3, 2012
Accepted July 5, 2012