Chance Fracture (flexion-distraction injury)
ANATOMY OF THE SPINE
The human spine is formed by individual vertebrae and connective tissue discs in between. The vertebrae form the spinal canal. There are seven cervical, twelve thoracic, and five lumbar vertebrae. The intervertebral discs are the link between the individual vertebral bodies.
Normal anatomy of the spine. Longitudinal section and cross sections through the cervical, thoracic and lumbar spine.
The little joints that link the vertebrae together are known as facet joints. They help to stabilize the spine and, together with the intervertebral discs, allow a certain degree of mobility of the spinal cord. The spinal canal should be wide enough to allow nerve roots to float freely in cerebrospinal fluid.
The front border of the spinal canal is built by the vertebral bodies and intervertebral discs, the side by the intervertebral joints (facets) and back by the ligamentum flavum (yellow band) and vertebral arches. Discs consist of an outer fibrous ring (annulus fibrosus), which surrounds an inner gel-like center (nucleus pulposus).
The spinal cord and nerve roots lie within the spinal canal. The spinal cord extends downwards approx. to the 1st lumbar vertebra. Below, only nerve roots are present in the spinal canal. At the level of the intervertebral disc the nerve roots pass through the neural root foramina to exit the spinal canal. The spinal cord and nerve roots conduct electric-like signals from the skin and joints to the brain, and process of movement is initiated from the brain to the muscles.
А flexion-distraction injury may cause a fracture of the vertebra and/or a rupture of the ligamentous injury. The mechanism involves compression of the first column of the spine and distraction of the posterior column. This injury is often associated with gastrointestinal injuries (50%) (aka Seat belt injury, car/motorcycle accidents, falling from great heights, sports accidents, ballistic trauma).
CAUSE OF SYMPTOMS
Acute compression of all nerve roots in the lumbar spinal canal
SYMPTOMS AND SIGNS
Severe pain along the spine over the fracture
Numbness, severe pain and weakness in both legs, loss of bladder/bowel control, numbness of the genitals and loss of sexual function (Cauda syndrome)
THE DIAGNOSIS IS BASED ON Medical history Clinical exam Computer tomography Magnetic resonance imaging (MRI) Radiographs
additionally you may have to do: Digital subtraction angiography Functional (dynamic) radiographs
The treatment may be non-surgical or surgical.
Non-surgical treatment may include
In neurologically intact patients with a stable fracture (bone only & intact posterior elements) Nonsteroidal anti-inflammatory drugs
Immobilization with brace
WHEN SHOULD AN OPERATION BE PERFORMED?
Patients with signs of nerve root compression
Neurologically intact patients with an unstable fracture (bone & posterior elements affected)
WHAT IS THE GOAL OF SURGERY?
To release the compressed nerve roots
To restore the protective function of the spine
HOW IS SURGERY PERFORMED?
Posterior decompression of the spinal canal + fusion
WHICH OTHER DISEASES SHOULD BE EXCLUDED (DIFFERENTIAL DIAGNOSIS)? Other fractures of the spine Ankylosing spondylitis (Bechterew's disease)
The condition is treated by medical spetialists in the field of: