Occipital condyle fractures have previously been viewed as relatively uncommon injuries; but with the increased utilization of CT scanning with reconstructions in the evaluation of suspected spine trauma patients, an increased incidence has been noted. It has been reported to occur in 3-15% of trauma patients. Presence of these fractures indicate high injury trauma.
Occipital condyle fractures may be stable or represent the bony component of occipitocervical dissociation.
Montesano classified these fractures into three categories.
Type I Fractures
These are usually stable fractures and thought to be the result of an impaction injury.
They occur as comminution of the tip of the occipital condyle.
Type II Fractures
These consist of an oblique fracture extending from the condylar surface into
the skull base. Fractures of this nature are likely caused by a shear mechanism and are likely unstable.
Type III Fractures
These are least common of the three.
They occur as a transverse fracture line through an occipital condyle. They are thought to occur as a result of an avulsion.
They are unstable and may represent the bony component of a craniocervical dissociation.
If a unilateral bony injury to an occipitocervical joint is identified, the contralateral side should be looked for any signs of a bony or ligamentous injury.
Due to association of occipitocervical dissociation, any occipital condyle fracture should be evaluated for it.
Type I and II fractures are usually treated conservatively with immobilization in a rigid cervical collar for 6-8 weeks.
Type III fractures should be treated with halo-vest immobilization if there is a suspicion of ligamentous instability. If there is evidence of craniovertebral subluxation, some authors advocate immediate occiput-to-C2 fusion.
Occipitocervical Dissociation
Occipitocervical dissociation is an uncommon injury which can be difficult to identify and has a high mortality. The most common mechanism of injury is that of a pedestrian struck by a car, with a high incidence in pediatric patients.
Obvious signs of instability are translation or distraction of more than 2 mm in any plane, neurologic injury, or concomitant cerebrovascular trauma.
The classification of these injuries is based upon the displacement of the occiput.
- Type I injuries are anterior subluxations and are the most common.
- Type II injuries have vertical distraction greater than 2 mm of the atlanto-occipital joint.
- Type III injuries are posterior dislocations and are rarely reported.
Once an injury is identified, prompt management is of the utmost importance.
Traction is contraindicated.
Treatment consists of immediate halo vest application with reduction of the subluxation and confirmation by CT scanning.
An occiput-to-C2 fusion is required in most cases to provide longterm stability.
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