Atlanto-axial instability
(AAI) is a condition that affects the bones in the upper spine or neck under the base of the skull. The joint between the upper spine and base of the skull is called the atlanto-axial joint. In people with Down syndrome, the ligaments (connections between muscles) are “lax” or floppy.
How do you treat AAI?
The treatment goals for persons with AAI are to protect the spinal cord, stabilize the spinal column, decompress neural tissue, and reduce any deformity. In most cases, the injury is purely ligamentous and unlikely to heal. Therefore, these injuries are typically treated with
posterior C1-2 fusion
.
What is a positive AAI?
“AAI denotes
increased mobility at the articulation of the first and second cervical vertebrae
(atlantoaxial joint). The causes of AAI are not well understood but may include abnormalities of the ligaments that maintain the integrity of the articulation, bony abnormalities of the cervical vertebrae, or both.”
What are the symptoms of atlantoaxial instability?
Neurologic manifestations include
clumsiness, lack of coordination, abnormal gait, difficulty walking, easy fatigability, neck pain
, limited next mobility, torticollis, sensory deficits, neurogenic bladder, upper motor neuron signs (spasticity, hyperreflexia, clonus, Babinski sign), paraplegia, hemiplegia, and ...
What causes atlantoaxial instability in Down syndrome?
Children with Down syndrome are at increased risk of developing compression of the spinal cord called atlantoaxial instability. This problem is caused by
a combination of low tone, loose ligaments and bony changes
. The spinal cord can be pressed by the bones and cause nerve damage.
Why can injuries at C1 or C2 be fatal?
Severe cases of spinal cord injury at C2 can be fatal
because breathing and other critical body functions may be impaired or stop
. Paralysis of the body below the injured region of the spinal cord may also occur in some cases.
Is atlantoaxial instability life threatening?
Objective Atlantoaxial dislocation (AAD) is
a rare and potentially fatal disturbance to the normal occipital-cervical anatomy
that affects some populations disproportionately, which may cause permanent neurologic deficits or sagittal deformity if not treated in a timely and appropriate manner.
What is Somi brace?
A sterno-occipital-mandibular immobilization device (SOMI) is
a rigid cervical brace that positions your neck in straight alignment with your spine
. This brace supports your neck by preventing your head and neck from moving. This level of immobility will allow the damaged structures in your neck to heal faster.
How does cervical instability happen?
Cervical instability occurs
when the ligaments in between your spinal cord and skull are loose
. These “lax ligaments” allow for excessive movement of the top two cervical vertebrae, which may result in many symptoms, such as headaches, fainting, or even memory loss.
What is the subluxation?
The term “subluxation” is used by doctors of
chiropractic to depict the altered position of the vertebra and subsequent functional loss
, which determines the location for the spinal manipulation. “Subluxation” has been defined medically as “...a partial abnormal separation of the articular surfaces of a joint.”
How is Craniocervical instability treated?
Treatment. Conservative treatment of craniocervical instability includes
physical therapy and the use of a cervical collar to keep the neck stable
. Cervical spinal fusion is performed on patients with more severe symptoms.
What causes C1 misalignment?
A misalignment at C0-C1-C2 can also come from
sitting at a desk with poor posture
, birth trauma, or falling out of a tree when you are a child. However, the most common way we see large trauma produced is from a concussion from either sports or work related injuries, or a car accident.
What does Atlantoaxial mean?
Medical Definition of atlantoaxial
:
relating to or being anatomical structures that connect the atlas and the axis
.
What ligament is affected in Down syndrome?
In persons with Down syndrome, congenital absence or laxity of
the transverse atlas ligament
(which may be associated with congenital anomalies of the odontoid bone) must be considered.
What is the difference between Mosaic Down syndrome and Down syndrome?
Mosaic Down syndrome, or mosaicism, is a rare form of Down syndrome. Down syndrome is a genetic disorder that results
in an extra copy of chromosome 21
. People with mosaic Down syndrome have a mixture of cells. Some have two copies of chromosome 21, and some have three.
What prevents atlantoaxial instability?
Individuals with AAI are restricted from participation in certain activities that may result in cervical spine injury. These include
gymnastics, diving
, pentathlon, butterfly stroke, diving starts in swimming, high jump, soccer, and certain warmup exercises.
