The axis (C2) cervical vertebra is the second vertebra of the spine. It is unique in that it contains the odontoid process — odontoid means “tooth” and that is what this bone looks like — that forms a pivot point on which C1 atlas can rotate. Injuries to the odontoid are common in motor vehicle accidents and falls.
The base of the skull (occiput) and atlas (C1) create the atlanto-occipital joint which connects the skull and spine. This joint is responsible for approximately 50 percent of the head’s ability for nod up-and-down (flexion-extension).
The C1 atlas and C2 axis form the atlantoaxial joint. The atlas (C1) rotates around the odontoid process of the axis (C2), allowing a person’s head to turn from side-to-side (rotate). This joint accounts for approximately 50 percent of the head’s ability to turn left and right.
The diameter of the spinal canal is largest at the upper cervical spine, particularly at the level of C2, so spinal cord injuries due to compression or pressure are not common. However, fractures of the C2 can occur.
Types of spine injuries to the C2 axis
Injuries to the C2 axis vertebra include:
- Fractures, including:
* Lateral mass fractures
* Extension teardrop fractures
* Traumatic spondylolisthesis, also called a "hangman's" fracture
* Odontoid fractures
* Rotatory subluxation of C1-C2 (atlantoaxial) joint
C2 axis injuries can be caused by:
- Motor vehicle accidents
- Sports or diving injuries
- Blood clots
- Birth injuries
Different types of C2 injuries are more common based on the age of the patient. For example, young children are more likely to suffer growth plate fractures and separations than an older child who has reached skeletal maturity.
Symptoms of a C2 axis spine injury can include:
- Swelling around the neck
- Difficulty breathing
- Tingling or loss of sensation in arms or legs
- Loss of bladder or bowel function
To diagnose injuries to the C2 axis, physicians at Children's Hospital of Philadelphia (CHOP) perform a comprehensive physical examination and detailed family history of your child.
We also use the following imaging tests to help determine your child’s diagnosis and the potential cause of the traumatic spine injury.
- X-rays, which use invisible electromagnetic energy beams to produce images of internal tissues, bones and organs on film
- Magnetic resonance imaging (MRI), which uses a combination of large magnets, radiofrequencies and a computer to produce detailed images of organs and structures within the body
- Computed tomography (CT) scan, which uses a combination of X-rays and computer technology to produce cross-sectional images (“slices”) of the body
At CHOP, treatment of C2 axis injuries are largely dependent on the location and severity of the injury. Injuries to C2 axis are classified as type 1, 2 and 3 and treatment protocols vary.
This is an injury to the bone where the periosteum — the connecting tissue around the bone — is still intact, but there is some injury to the area around the C2 axis.
This type of injury is treated with a halo-vest worn for six to eight weeks. The child’s head is supported by a halo, which is stabilized by pins placed directly into his or her skull. Extending from the halo are metal rods that connect to a padded vest worn around the child’s chest and back. The halo-vest keeps the child's head immobilized and supported while the injury heals.
This is a neck injury where the periosteum may be damaged and there is moderate risk of spinal cord injury.
Treatment is a halo-vest as described above. These injuries take anywhere from eight to 12 weeks to heal.
This is a fracture of the neck, where the injury may have also involved the C3, the next vertebra down the child’s spine.
Treatment may be immobilization with a halo-vest or surgery, depending on the extent of the fracture, with an approximate eight to 12 week recovery period.
This is extensive injury to the neck and includes a high risk of spinal cord injury.
Type 3 injuries are usually treated with spinal fusion, a surgical technique to join two or more vertebrae to prevent further instability.
At CHOP, we offer a wealth of ongoing support and services to your child and family. Your child will have access to clinical services such as physical and occupational therapy, as well as psychosocial support from social workers and psychologists who can help your child deal with any emotional effects of the C2 axis injury.
If your child needs surgery, we take every precaution to ensure safety in spine surgery. Our multidisciplinary approach helps us to address all aspects of your child’s care and treatment.
While surgery can dramatically improve traumatic spine injuries, it can also be a stressful experience for you and your child. Our team can help you prepare your child for surgery and know what to expect during surgery.
Additionally, we recognize your child's pediatrician or referring physician as an important part of your child's care team and provide regular updates about your child's progress.
Anytime your child has a neck injury, it is important to follow-up with a physician. In some cases, pain, breathing difficulty or paralysis may develop later — even if the symptoms were not present during your child’s initial evaluation or treatment.
Your physician will advise you about an appropriate follow-up schedule for your child. Follow-up care is available at CHOP's Main Campus or at any of our CHOP Care Network locations.
Our pediatric clinical professionals will follow your child with a traumatic spine injury until young adulthood (between age 18 and 21) and help transition to adult orthopaedic care, if needed.
Long-term outcomes for children with C2 axis injuries vary from patient to patient and depend on the severity of the injury to the C2 axis.
In some cases, children recover full mobility; in others, paralysis and difficulty breathing can be lifelong after effects of the injury. A ventilator may be necessary to aid in breathing.
Surgeons at CHOP have published research on treatment and outcomes for children with traumatic atlanto-occipital dislocation. For details, read the study abstract.