Chance Fracture (flexion-distraction injury)

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.

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).

Acute compression of all nerve roots in the lumbar spinal canal

Vertebral fracture

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 treatment may be non-surgical or surgical.

In neurologically intact patients with a stable fracture (bone only & intact posterior elements)

Patients with signs of nerve root compression Neurologically intact patients with an unstable fracture (bone & posterior elements affected)

To release the compressed nerve roots

To restore the protective function of the spine

Posterior decompression of the spinal canal + fusion