To restate, a Low-Grade Spondylolisthesis is one which is a Meyerding Grade 1 or 2.
This means the vertebra has slipped forward up to 50%
of the vertebral body. To use a football analogy it hasn’t crossed the 50-yard
line. Below is a Grade 2.
We typically call spondylolistheses “slips”.
What is the most
common symptom for Low-Grade slips? Just like spondylolysis/pars
fractures, the main symptom for Low-Grade slips is low back pain which worsens
with activities. There is a wide range
of symptoms, from no pain to severe disabling pain.
Are there other
symptoms? At times there will be nerve root pain, or sciatica down one
or both legs. This type of pain is
usually not constant, but more episodic, and worsens with more stressful
activities, such as sports. If present,
this type of pain can be described as “shocky” but also people report decreased
sensation or numbness in part of the leg.
So how do we treat
Low-Grade slips? There are
several factors which must be considered: previous treatment, length of
symptoms, type and severity of symptoms, and how symptoms interfere with
activities (sports and activities of daily living).
1.
The first intervention is pain management
(over-the-counter medications), activity modification, and physical therapy for
paraspinal and core muscle strengthening.
These interventions can be continued long-term, and we discussed these
interventions in the previous posts on spondylolysis.
2.
If all nonsurgical management fails to
adequately relieve the back +/- leg pain, then surgery may be an option.
What is “surgery”
for a Low-Grade Spondylolisthesis? The main goal is to halt the slip
progression and to fuse the slipped vertebra to the vertebra on which it is
slipping.
The below case is
how I generally treat Low-Grade slips surgically:
There is a midline incision on the low back
The spine is exposed
Since most of the surgical cases are the isthmic type (have
pars fractures), the loose posterior elements are removed, which is called a
Gill laminectomy.
The nerve roots are identified and decompressed if
necessary.
Pedicle screws are placed into the two vertebra to be fused.
The disc space is opened up, from the back and the disc is
removed.
To improve the stability of the one-level fusion, a cage is
placed between the vertebral bodies (where the disc was before removal) and
bone is also placed in the disc space.
This also allows the vertebra to be fused in the front.
The slip MAY be reduced.
Rods are placed (one on each side) to stabilize the
vertebra.
Bone graft is placed to get a fusion in the back of the
spine.
The surgical wound is closed over a drain (which evacuates
blood which collects in the surgical site).
