Cervical spine injuries and flexibilities following axial impact with lateral eccentricity

Abstract

Dynamic axial compression loading of the cervical spine with high lateral eccentricities produced primarily soft tissue injuries resulting in more post-injury spinal flexibility in lateral bending and axial rotation than that associated with the bony fractures resulting from low eccentricity impacts.

A neck compression injury criterion incorporating lateral eccentricity

“…Data from a previously-published experimental program 27,28 is included in this study. These experiments tested 12 specimens in two lateral eccentricity magnitudes of the applied compressive force (low and high) with the superior end of the specimen allowed to laterally rotate and translate (translation-free), see Table 1.…”

“…Dynamic testing was carried out on each specimen to simulate loading that would occur to a spine segment during a head-first impact event. One loading run was carried out on each specimen following flexibility testing, described in detail elsewhere 27,30 , which pre-conditioned the specimen. The prepared specimen was inserted into a custom rig incorporated into a materials testing system (Model 8874, Instron, Norwood, Massachusetts).…”

“…The small number of tests and limited range of lateral force eccentricities prohibit determining compression and lateral bending injury criteria and corresponding tolerance values from this data set alone. Our laboratory has previously performed experiments compressing 12 three-vertebrae cervical spine segments and their intervertebral tissues at two degrees of lateral eccentricity (low and high) in a single boundary condition that allowed the superior end of the specimen to translate and rotate in the coronal plane 27,28 . These previous studies found that high eccentricity specimens experienced more soft tissue injuries, less bony fractures, less compressive force and higher lateral bending moments compared to the low eccentricity group.…”

“…Full details on these specimens are available in a separate publication 30 . The two experimental protocols described above 27,28,30 were compiled with the aim of determining a novel injury criterion with corresponding tolerance levels for cervical spine segments in axial compression applied with varying degrees of coronal plane eccentricity. Here, we examined the potential for a lateral Nij criterion and an eccentricity-based criterion in this load condition.…”

META: an MRI-based scoring system differentiating metastatic from osteoporotic vertebral fractures

“…Discriminant analysis is a method used in pattern recognition to find a combination of features that characterize two classes of objects [25], and it is now widely accepted as a method to create a model for decision making in spine surgery [26][27][28]. It involves the calculation of linear discriminant function by multiple regression analysis as follows:…”