Correlations between posterior longitudinal injury and parameters of vertebral body damage.

Background: The posterior longitudinal ligament (PLL) is an important structure of spinal stability. The loss of vertebral body height, local kyphosis (LK), and canal compromise may lead to spinal instability. This study determined the correlations between injury of the PLL and the loss of vertebrae height, kyphosis, and canal compromise.
Materials and Methods: A retrospective review of a thoracolumbar burst fracture database was conducted from January 2009 to December 2011. Patients were divided into an intact group and a disrupted group according to the status of the PLL. The loss of vertebral height, mid-sagittal canal diameter, and LK was measured. The anterior, middle, and posterior vertebral compression ratios (AVBCR, MVBCR, and PVBCR) and mid-sagittal diameter compression ratio (MSDCR) were calculated.
Results: Forty-seven patients were included in the study, including 25 patients in the intact group and 22 patients in the disrupted group. There were significant differences in the AVBCR (t = -3.048, P = 0.004), MVBCR (t = -2.301, P = 0.048), PVBCR (t = -2.116, P = 0.040), and MSDCR (t = -4.095, P = 0.000) but no difference in the LK (t = 0.408, P = 0.686) between the two groups. There was a positive correlation between the injury of the PLL and the MSDCR (r = 0.428, P < 0.01), AVBCR (r = 0.372, P < 0.01), and PVBCR (r = 0.271, P < 0.05). There was no correlation between the injury of the PLL and the LK and MVBCR.
Conclusions: The MVBCR and LK are not predictive of a PLL injury. The MSDCR, AVBCR, and PVBCR were associated with a PLL injury.
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