Chance fracture

Case contributed by Dr Edward Oates

Presentation

Single vehicle MBA @ 120kmh on a remote dirt road in desert shrublands. The patient had ridden into a hidden drainage ditch, and was catapulted into and over the handlebars. GCS 15 at time of retrieval, with bilateral lower limb neurological deficit. Road retrieval with sedation and analgesia, without ventilatory support. Major trauma response initiated at small remote receiving hospital.

Patient Data

Age: Mid 30's
Gender: Male
CT

Devastating vertebral injuries at the levels of T6-T7-T8.

Starting with the most intact vertebral body at T8 - there is anterosuperior wedge shaped destruction of the anterior column with marked bony loss. The middle column, in particular its interface with the spinal canal appears undisrupted, although minimally displaced bony injury to the posterior elements at this level is noted.

There is a chance fracture of T7. This is associated with superior/posterior dislocation of the T7 vertebral body. Some bony fragmentation persists in the original anatomical position of the T7 body (particularly of note is an anteroinferior fragment of T7 still attached to an anterosuperior fragment of T8), otherwise the superior aspect of the T7 body has been dislocated and retropulsed into the paraspinal musculature and subcutaneous soft tissues.

T6 is not able to be seen as an identifiable structure in this limited series of images. Suffice to say it does not exist in its normal anatomical location, and it's obliterated components likely make up part of the retropulsed fragmentation that is seen in the region of injury.

Hematoma and soft tissue swelling immediately anterior to the level of injury is noted. The great vessels in this area are not completely imaged (plus it's a non contrast scan), but appear to have escaped significant injury.

Spinous process fracture of T3 is noted. 

Axial lung window images demonstrate bilateral hemothoraces with bilateral parenchymal lung injuries. Although poorly defined due to lung window settings, the retropulsion of the T7 (and T6?) vertebral bodies can be seen in the paraspinal musculature. Obliteration of the spinal canal at this level is evident.

Case Discussion

An extreme example of a chance fracture, with profound destruction of the involved and neighbouring vertebral bodies, and retropulsion of bony fragments into the paraspinal musculature and subcutaneous soft tissue.

This is one of those cases where the final resting place of the bony fragments really tells a story of the forces and dynamics involved during the mechanism of injury. An understanding of the basic mechanisms of a chance fracture (flexion-distraction) is required to help understand how these fragments got where they did.

Comparison with other cases (such this) allows a better understanding of how such bony destruction evolves through the mechanism of injury.

Such a severe injury, with destructive compromise of the spinal canal was naturally associated with non recoverable traumatic cord injury (cord transection) .

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Case information

rID: 38398
Case created: 17th Jul 2015
Last edited: 23rd Apr 2017
Inclusion in quiz mode: Included

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