Spondylolysis and Spondylolisthesis
A
spondylolysis is a type of broken bone in the spine. Both struts holding the
front and back parts of the bone together break. The back part of the vertebral
bone (the lamina) separates from the front part (the body). Because of the
broken bone, the spine can become unstable and the body can slip forward. The
slippage is called a spondylolisthesis.
Spondylolisthesis is graded. Higher numbers indicate a
more severe problem. There are five grades, or levels, of severity.
To determine the grade of spondylolisthesis, or slippage,
the disc is divided in quarters. The grade is equal to the number of quarters
of slippage. If there is no slippage, the grade is zero. If the slippage is
equal to one quarter of the total width of the disc, the slippage is grade one.
If the slippage is three quarters of the width of a disc, it is a grade three
spondylolisthesis. If the slippage is more than four quarters (the whole disc
space) then it is called a grade 5. In a grade 5 spondylolisthesis, the spine
is completely dislocated.
Go to the next
chapter on
symptoms, starting with back pain.
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