Spondylolisthesis
What is
it?
Forward displacement of one
vertebra over another, usually of the fifth lumbar over the body of the sacrum,
or the fourth lumbar over the fifth, usually due to developmental defect. Click
here for spondylolisthesis animation.
Often occurs as a result of
degenerative disc disease and facet deficiency. It is often associated with
intersegmental instability and with central stenosis. More commonly involves
older black females and diabetics (affects females 6 times as much as males).
Involves L4-L5 level four times more often than the L5/S1 level. This is more
common in patients with transitional L5 vertebrae. Degenerative
spondylolisthesis often causes radiculopathy related to nerve compression
within the foramen (i.e., L4/L5 spondylolisthesis will cause a
L4radiculopathy). Nerve compression occurs between the superior end plate of
the caudad vertebra and the inferior facet of the cephalad vertebral body. The
forward displacement that takes place, will shift the weight bearing structures
from the disks to the facets, thereby causing a lumbar facet syndrome with low
back and leg pain, which occasionally will travel down to the ankles, but more
commonly, it will only go as far as the back of the knees or the buttocks.
Alternatively, it can cause untoward sheering forces on the lumbar disks,
causing discogenic low back pain, characterized by pain in the center of the
lower back, with sitting intolerance.
X-rays are taken in the standing
position to accentuate slippage. In degenerative spondylolisthesis, slippage
rarely exceeds 35%. There are four (4) different grading of displacement. Grade
I through grade IV. Grade III and IV are the most severe, and may require
surgery to fuse the affected levels.
NON-OPERATIVETreatment
Indicated for patients who can be
managed with NSAIDS, epidural steroids, bracing, and/or change of job type. In
up to 30% of patients, additional slippage may occur. Lumbar facet blocks,
followed by radiofrequency neurotomy may be of help with the pain. Similarly,
if discogenic pain is present, intradiscal electrothermal annuloplasty
/nucleoplasty, may be of benefit in relieving some of the pain. More difficult
cases may require implant therapy.
Decompression of the nerve
roots& stabilization by posterolateral fusion. In the study by Nork et al
(Spine1999), 93% of patients were satisfied with decompression and fusion (with
instrumentation) for degenerative spondylolisthesis. In the study by
Herkowitzand Kruz Spine 1991, 96% of patients had good to excellent results
with decompression and fusion (w/o instrumentation) vs. 44% of good to
excellent results in patients with decompression alone. In patients who
underwent decompression alone, further slippage was often seen to occur.