Dural tears in spinal burst fractures: predictable MR imaging findings.

BACKGROUND AND PURPOSE The diagnosis of traumatic spinal dural tears is difficult to establish. The purpose of this study was to determine the reliable MR imaging findings suggesting dural tears in spinal burst fractures. MATERIALS AND METHODS We retrospectively reviewed spine MR images of 21 patients with dural tears (study group) and 33 patients without dural tears (control group), all of whom had spinal burst fractures. The following MR imaging features were compared between the 2 groups: the interpedicular distance, the angle of the retropulsed segments, the ratio of the central canal diameter, the presence or absence of laminar fractures, the degree of laminar fractures, and the extent of epidural hemorrhage. RESULTS The mean values of the grade of the laminar fracture, the interpedicular distance, the ratio of the central canal diameter, the angle of the retropulsed segment, and the extent of epidural hemorrhage in the study and control groups were as follows: 1.77 and 0.86 (P = .034), 28.7 and 26 mm (P = .02), 0.37 and 0.58 (P = .008), 112 degrees and 128 degrees (P = .05), and 2.37 and 1.4 (P = .11), respectively. The ratio of the central canal diameter was the most reliable factor suggesting dural tears compared with other factors. CONCLUSIONS Dural tears are likely when there are MR imaging findings of laminar fracture of more than grade 1, the interpedicular distance is >28 mm, the central canal ratio is <0.46, and the acute angle of the retropulsed segment is <135 degrees .