Chance Fracture

Chance Fracture of the Spine

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- Discussion:
    - Chance frx & posterior ligament rupture (variant of flexion distraction injury pattern) may
          present w/ minor anterior vertebral compression;
          - in Chance frx, the anterior column fails in tension (along w/ the middle and posterior columns),
                 where as flexion distraction fracture involve compression of the anterior column and
                 distraction of the middle and posterior columns;
    - approx 1/2 of pts w/ flexion distraction injury pattern have primarily ligamentous rupture;
          - rupture usually includes interspinous ligament, ligamentum flavum, facet capsule, posterior
                 annulus, and thoracodorsal fascia;
    - whether the injury is purely ligamentous or includes a fracture thru vertebral body, all three columns
          rupture in distraction (tension);
    - often these are misdiagnosed as a compression frx;
          - the occurance of a traumatic compression fracture in a young patient (following MVA) should
                 raise the possibility of a Chance fracture;
          - either good quality AP view is necessary to rule out posterior element injury, or a CT scan is
                 required (if the AP view remains equivocal);

- Exam:
    - seldom assoc w/ neurologic compromise unless
    - abdominal injuries are common and occur in upto 50-60% of patients;
    - references:
          - The epidemiology of seatbelt associated injuries.
                 PA Anderson et al.  J. Trauma. Vol 31. 1991. p 60-67.

- Radiographs:
    - significant translation on lateral;
    - anterior wedging may be minimal;
    - often only a portion of the vertebral body will be involved (half ligamentous and half bony injury);
    - look for frx line extending thru spinous process, lamina, pedicles, & portion of the vertebral body;
    - often the AP view will best show the posterior element injury (lamina frx will appear as a "lazy W")  

- CT Scan: is often ordered to help make the diagnosis;

   

- Non Operative Treatment:
    - Chance Frx may initially be unstable, but after 2 weeks there will be sufficient bony healing
           to allow fitting for an orthosis;
           - patients w/ partial vertebral body involvement (half bony injury and half ligamentous injury)
                  may be candidates for non operative treatment is alignment is acceptable;
    - candidates for non operative treatment should have less than 15 deg of kyphosis;
    - patients should be fitted for a custom molded hyperextension orthosis;
    - fractures below L3 may require the addition of a thigh extension;

- Indications for Operative Treatment:
    - w/ Ligamentous Chance Injury, soft tissue healing is unreliable, and about
           half of all patients treated non operatively will have poor outcomes;
           - progressive kyphosis is one of the major complications w/ non-op Rx;