Fracture Dislocations of the Spine

- Discussion:
    - fracture dislocation injuries involve disruption of all three columns by a combination of compression, tension, rotation, and/or shear;
    - posteror to anterior shear type:
         - occurs w/ direct load to back, superior vertebral body segments are displaced anteriorly with respect to those below;
         - vertebral bodies usually remain intact;
         - orientation of facet joint prohibits anterior displacement of posterior arch, resulting in multiple frx thru post. arch;
         - lamina become detached from anteriorly displaced vertebral body segment, resulting in a free floating lamina;
         - dural tears are common;
    - anterior to posterior shear type:
         - posterior arch can be displaced posteriorly w/o inferior facet limiting displacement;
         - as result, AP shear injuries rarely have assoc dural tears;
    - flexion and rotation mechanism:
         - anterior columns fails by compression & rotation;
         - middle column fails primarily by rotation;
         - failure may occur thru the disk or vertebral body;
    - flexion distraction type:
         - this is distinguished from the simple flexion distraction Chance type injury by the presence of significant translation;
         - this is a highly unstable injury often assoc w/ neurologic deficit, dural tears, & intra-abdominal injuries;

- Associated Injuries:
    - intra abdominal injury;

- Thoracic Frx Dislocations:
    - if frx dislocation is above T7 or above and there has been no frx of ribs bilaterally or sternum, the spinal cord will be stable and only 
           conservative treatment is needed;
    - if there is a similar injury below T7, the frx will be unstable;
    - posterior instrumentation and fusion is indicated;

- Lumbar Spine Fracture Dislocation:
    - flexion injury w/ axial compression;
    - posterior ligaments ruptures & drives upper vertebral body into one below;
    - w/ rupture of posterior ligaments & loss of vertebral body (anterior column) support, upper spine will sublux or dislocate anteriorly;
          - w/ loss of both anterior and posterior stability, frx dislocations frequently present with rotational deformity as well;
    - radiographs:
          - more than 50% anterior collapse of the vertebral body;
          - widening of the spinous processes,
          - anterior translation, & displaced frx of posterior vertebral wall;

- Treatment:
    - frx dislocations are usually assoc w/ severe neurologic impairment;
    - goal of treatment is to realign spinal column and provide adequate posterior stabilization so as to allow for early mobilization

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Thursday, April 12, 2012 10:01 am