Reverse and pseudoreverse cortical sign in thoracolumbar burst fracture: radiologic description and distinction--a propos of three cases

Eur Spine J. 2009 Feb;18(2):282-7. doi: 10.1007/s00586-008-0848-x. Epub 2008 Dec 12.

Abstract

In thoracolumbar burst fracture the "reverse cortical sign" is a known entity that corresponds to a fragment of the posterior wall that has been flipped 180 degrees with the cancellous surface of the fragment facing posteriorly in the canal and the cortical surface (posterior wall) facing anteriorly. The identification of such reverse cortical fragment is crucial as ligamentotaxis is classically contraindicated as the posterior longitudinal ligament is ruptured. Recognition of such a flipped cortical fragment has relied so far on the axial CT. The advent of CT scans with sagittal reconstruction has allowed us to better describe such entities that have received little attention in the literature. The goal of this report was therefore to describe the appearance of the reverse cortical sign and its likes as they can appear on axial CT scans, sagittal reconstructions and MRI. During 1-year practice at our institution we had to treat three patients with thoracolumbar burst fracture associated with what looked like a reverse cortical sign on the axial CT scans. Further analysis of the sagittal reconstruction CT could differentiate the true reverse cortical sign from a new entity that we coined "the pseudoreverse cortical sign" as observed in two out of the three cases. In the pseudo reverse cortical sign what appears to be a flipped piece of posterior vertebral body is actually part of the superior or inferior endplate that is depressed into the comminuted vertebral body. In such cases the posterior longitudinal ligament appears to be in continuity and therefore such fracture can theoretically be treated with posterior ligamentotaxis as evidenced in one of our case. Careful analysis of the CT scan and specifically the sagittal reconstruction and MRI can differentiate two separate entities that may correspond to a different severity injury.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Female
  • Humans
  • Longitudinal Ligaments / diagnostic imaging
  • Longitudinal Ligaments / pathology
  • Longitudinal Ligaments / surgery
  • Lumbar Vertebrae / diagnostic imaging*
  • Lumbar Vertebrae / pathology
  • Lumbar Vertebrae / surgery
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Spinal Fractures / diagnostic imaging*
  • Spinal Fractures / pathology
  • Spinal Fractures / surgery
  • Thoracic Vertebrae / diagnostic imaging*
  • Thoracic Vertebrae / pathology
  • Thoracic Vertebrae / surgery
  • Tomography, X-Ray Computed