Tolerance of the Cervical Spine to Eccentric Axial Compression

Acoustic emission signals can discriminate between compressive bone fractures and tensile ligament injuries in the spine during dynamic loading

“…These two types of injuries are often present in the same spine specimen in experiments inducing bending moments (Carter et al, 2002;Przybyla et al, 2007). The present data confirm the potential of using AE sensors to distinguish between these types of injuries in the spine; however, further research will be required to advance this technique for use in experiments with larger segments of the spine.…”

“…This was necessary to simulate the failure modes that are thought to result in most injuries of these tissues in vivo and which have been demonstrated in ex vivo models (McElhaney et al, 1979;Allen et al, 1982;Yoganandan et al, 1989;White and Panjabi 1990;Carter et al, 2002;Torg et al 2002;Thompson et al, 2009), and so that we could be certain that AE signals were from one tissue type. Although the present study indicates differences in AE signals between tissues and loading conditions, these two conditions may be present in the same specimen under eccentric axial compression loading (Carter et al, 2002). Differences between AE signals resulting from tensile ligament injuries and compressive vertebral body fractures would assist in differentiating between these two types of failure in the same FSU under this loading condition.…”

“…These failure loads are often subjectively determined using changes in slope of the force or moment response curves (Maiman et al, 1983;Shea et al, 1991;Pintar et al, 1995;Carter et al, 2002). Acoustic emission (AE) sensors could provide more objective data on the timing of injury as they record dynamic stress waves generated by the release of energy in a material, such as the initiation of a fracture (Kohn, 1995) and they have been used to identify the time of injury of skull, ankle, and tibia bones (Allsop, 1991;Funk et al, 2002a;Rudd et al, 2004;Cormier et al, 2008).…”

Cervical spine injuries and flexibilities following axial impact with lateral eccentricity

“…Numerous studies using cadaver spines have evaluated injurious sagittal plane compression of the cervical spine [23][24][25][26][27], while, to our knowledge, only two studies and few specimens have examined injurious compression-lateral bending loading [28,29]. The spectrum of injuries produced under axial compression with lateral bending is largely unknown and understanding these is essential to design devices and methods to prevent such injuries and for the identification, evaluation, classification, and treatment of patients with such injuries.…”

Moment Measurements in Dynamic and Quasi-Static Spine Segment Testing Using Eccentric Compression are Susceptible to Artifacts Based on Loading Configuration

“…These tolerance values may be determined through dynamic experiments using segments of the cadaver spine [5][6][7][8][9][10], Bending moments are also applied quasi-statically in ex vivo models to evaluate spine mechanics [11] and to assess surgical implants [12,13], Accurate measurement of the applied bending moments in these experiments is essential for the development of optimal injury prevention and treatment strategies for the spine.…”