Hyperextension Injuries: (19-38% of cervical injuries)

- See:
    - Central Cord Syndrome:
    - Extension Teardrop Fracture of C2
    - Hangman's frx
    - Jefferson Fracture
    - Lower Cervical Burst Fractures
    - Hyperextension fracture dislocation
    - Prevertebral Soft Tissues
- Discussion:
    - hyperextension injuries may include:
         - hyperextension sprain;
         - Hyperextension dislocation;
         - traumatic spondylolisthesis (Hangman's frx of C2);
         - avulsion injury of the Atlas or Axis;
         - isolated laminar fractures;
    - may occur from a blow to the face (& accompanied w/ fascial frx)
    - mechanism involves distractive anterior forces and compressive Posterior column forces;
    - pts w/ severe Spondylosis may suffer neurologic deficit w/ no radiographic fractures or subluxations;
    - cord is pinched between posteriorly projecting osteophytes & thickened, bulging ligamentum flavum;
    - C2 Laminar Frx:
           - isolated laminar frx of Axis have also been described & may be confused w/ traumatic spondylolisthesis;
           - laminar frx occurs posterior to the pars interarticularis, & unlike Hangman's frx, is considered a stable injury;
           - because of diffus sclerosis in pts w/ Spondylosis, laminar frx may be difficult to detect on plain films;
           - while they are stable, fragments may compromise canal & impinge on cervical cord resulting in deficits;
    - injuries resulting in anterolisthesis include:
           - unilateral facet subluxation (shows > 3-6 mm of anterior offset)
           - hyperflexion strain - results in less offset;
- Radiographs:
    - unilateral articular mass frx are seen on AP film as disruption of undulating lataeral margin;
    - lateral film:
    - oblique film:
    - prevertebral soft tissue swelling;
    - widening of intervertebral disc space;
    - fractures of the posterior elements;
- Treatment:
     - pts with cord or nerve root dysfunction due to hyper-extension injuries are managed non surgically with an orthosis, & their neurologic 
           status is carefully monitored

Hyperextension-dislocation of the cervical spine. Ligament injuries demonstrated by magnetic resonance imaging.

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

Last updated by Data Trace Staff on Thursday, December 22, 2011 12:31 pm