1Biomechanics Research Laboratory, Department of Orthopedics and Rehabilitation, Yale University School of Medicine, New Haven, Connecticut
2Department of Orthopaedic Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
Objectives: To quantify the strains in the cervical spine ligaments during simulated frontal impact and investigate injury mechanisms.
Summary of Background Data: Clinical and biomechanical studies have documented injuries to cervical spine ligaments during frontal impact. There are no biomechanical studies investigating subfailure injury mechanisms to these ligaments during simulated frontal impacts of increasing severity.
Methods: The whole cervical spine with muscle force replication model and a bench-top sled were used to simulate frontal impacts at 4, 6, 8, and 10g horizontal accelerations of the T1 vertebra. The peak ligament strains during frontal impacts were compared with physiologic strain limits determined during intact flexibility testing.
Results: Significant increases (P < 0.05) in the supraspinous and interspinous ligaments and the ligamentum flavum strains beyond physiologic limits were observed throughout the cervical spine, with the highest strains occurring at C3–C4. Significant increases were observed in the capsular ligament strains only during the 10g impact, whereas the posterior longitudinal ligament strains did not exceed physiologic limits.
Conclusions: The supraspinous and interspinous ligaments and the ligamentum flavum may be at risk for injury due to excessive strains during frontal impacts.