The odontoid is a part of the axis. When the odontoid breaks, you cannot turn and twist your neck freely. Odontoid fractures are common in children.
Odontoid fracture accounts for approximately 15% of all cervical spine fractures. Motor vehicle accidents and falls comprise the major mechanisms of injury. Patients often present with neck pain or evidence of myelopathy, such as sensory deficit or loss of fine motor control. In the elderly, spasticity may be the only presenting sign.
Three types of odontoid fractures are recognized. A type I odontoid fracture is an oblique fracture through the tip of the dens. It is an avulsion fracture at the site of the insertion of the alar ligament. This type of fracture is considered mechanically stable, but it may be associated with atlanto-occipital dislocation, which is unstable and potentially life-threatening and thus should be excluded. 2,3 Type I fractures are uncommon and comprise approximately 5% of odontoid fractures.
A Type II odontoid fracture occurs right where the odontoid process attaches to the C2 vertebral body. Without this piece of bone in place, the first two vertebral bones (the atlas and the axis) can slide apart. This puts a tremendous compressive or stretching force on the spinal cord as it goes down through the spinal canal . The spinal canal is a round opening or hollow tube formed by the vertebrae stacked on top of each other.
Symptoms of an odontoid fracture can range from none to mild pain to total paralysis. Many patients with odontoid fractures have no neurologic deficits but may complain of pain and spasms. Neurologic deficits can develop, however, in the weeks to months following injury as a result of delayed or gradual subluxation at the fracture site. Most odontoid fractures occur secondary to flexion with loading on the cervical spine and can result in displacement of the odontoid process anteriorly. Less commonly, there is extension of the cervical spine with loading and posterior displacement of the dens (the odontoid process).
Odontoid fracture should be considered in the differential diagnosis of a non-traumatic patient who develops sudden pain in the neck. Detailed history, accurate physical examination, and advanced radiological techniques, such as high-quality CT with reconstruction, are important for detection of occult cervical spine fractures in the Emergency Department.
There is insufficient evidence to establish a standard or guideline for odontoid fracture management. Given the extent of Class III evidence and outcomes reported on Type I and Type III fractures, a well-designed case-controlled study would appear to provide sufficient evidence to establish a practice guideline, suggesting that cervical immobilization for 6 to 8 weeks is appropriate management. In cases of Type II fracture, analysis of the Class III evidence suggests that both operative and nonoperative management remain treatment options. A randomized trial or serial case-controlled studies will be required to establish either a guideline or treatment standard for this fracture type.
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