Correlation of Interpedicular Distance with Radiographic Parameters, Neurologic Deficit, and Posterior Structures Injury in Thoracolumbar Burst Fractures.

OBJECTIVE: To correlate interpedicular distance (IPD) with radiographic parameters, neurologic deficit, and posterior structures injury in patients with thoracolumbar burst fractures.

METHODS: A total of 103 patients with a thoracolumbar burst fracture retrospectively reviewed. IPD was measured from the medial sclerotic areas of the pedicles on anteroposterior plain radiographs. Data on local kyphosis (LK), the ratio of anterior to posterior vertebral height (A/P ratio), loss of vertebral body height (LOVBH), spinal canal stenosis (SCS), neurologic status, and injuries to posterior structures (lamina, posterior ligamentous complex, and facet joint) were correlated with IPD using correlation analysis. Logistic regression analysis was used to determine the threshold of IPD predictive of neurologic deficit and posterior structure injury.

RESULTS: Of the 103 patients, 98 (95.15%) presented with increased IPD, ranging from 1.41% to 41.53% (mean, 10.92 ± 3.37%). Regarding radiographic parameters, both LK and SCS were linearly correlated with IPD. There was a significant correlation between IPD and neurologic status; logistic regression analysis identified an IPD increase of >20% as an indicator of neurologic deficit. In addition, both facet joint injury and lamina fracture were associated with IPD, with an IPD increase >15% as an indicator of facet joint injury and an IPD increase >20% a predictor of lamina fracture.

CONCLUSIONS: Our results indicate that IPD is correlated with LK, SCS, neurologic status, facet joint injury, and lamina fracture. Our data demonstrate that IPD measured from plain radiographs is a reliable indicator for assessment of thoracolumbar burst fractures.