Atlantoaxial Instability or Fractures

What is atlantoaxial instability?

There are 33 vertebrae (bones) of the spine that are generally divided into three main sections: the lumbar (lower), thoracic (middle), and cervical (neck) regions. There are seven vertebrae of the cervical spine that are identified by their letter C (cervical) and a corresponding number. C1 is at the base of the skull while C7 is near the bottom of the neck.

Sitting at the top of the cervical spine, C1 (atlas) and C2 (axis) form the atlantoaxial joint, a crucial part of the body that is primarily responsible for the left and right rotation of the neck and head. In a healthy spine, the joint at C1-C2 allows for as much movement as possible while still providing structural support. Sometimes, however, there is excessive movement at the base of the skull between C1 and C2. When this happens, it is known as atlantoaxial instability, which can lead to misalignment and compression of the spinal cord. Doctor Andre M. Samuel, orthopedic spinal doctor, treats patients in Clear Lake, Houston, Sugar Land, TX area who have been diagnosed with atlantoaxial instability.

What causes instability in the cervical spine at C1-C2? 

In adults, atlantoaxial instability can be caused by chronic joint degeneration over time, such as arthritis, or it can also be caused by acute or traumatic events, such as a transverse ligament injury or a C1 or C2 fracture. Infections, excessive blood flow (hyperemia), or conditions such as rheumatoid arthritis, have also been known to be factors.

As with adults, infection or injury can cause atlantoaxial instability in children, but it can arise from congenital factors as well. Down syndrome, Morquio syndrome, Larsen syndrome, Grisel’s syndrome, Kniest syndrome, as well as osteogenesis imperfecta, neurofibromatosis, and metatropic dysplasia have all been linked to atlantoaxial instability.

What are the symptoms of atlantoaxial instability?

There are a variety of symptoms that could indicate the presence of atlantoaxial instability or a C1-C2 fracture, but most will involve neck pain, numbness, or tingling. You may also experience dizziness, vertigo, difficulty walking, rapid heart rate, limited ability to move the neck, brain fog, or neurological symptoms such as difficulty swallowing.

How are atlantoaxial fractures or instability diagnosed?

To diagnose atlantoaxial instability or cervical fractures, Dr. Samuel will carefully review your medical history, perform a manual exam, and order diagnostic imaging. He may order a Dynamic Motion X-ray (DMX), CT Scan with motion, and/or a static or dynamic MRI of the upper neck. Dr. Samuel will need to determine the severity of the condition to help you make an informed decision as to the best way to treat the atlantoaxial instability.

What is the treatment for atlantoaxial fractures or neck instability?

Non-surgical treatment:

Depending on the severity and symptoms presenting, Dr. Samuel may suggest non-surgical options to treat atlantoaxial fractures or neck instability. They may include rest, physical therapy, pain management with medicine or injections, or orthotics (such as a cervical collar).

Surgical treatment:

In severe cases, or when more conservative measures are not deemed adequate, it may be determined that a fusion procedure is the best treatment to address the instability. C1-C2 cervical fusion can be done using a minimally invasive technique. This technique utilizes a small incision with stability the C1 and C2 bones using hardware and bone graft. ]