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D
egenerative
spondylolisthesis
:
surgical
treatment
R
ev
A
ssoc
M
ed
B
ras
2014; 60(5):400-403
401
Recommendation
After 12 weeks of unsuccessful conservative treatment,
surgery is a treatment option for these patients (
B
).
I
s
it
necessary
to
refer
the
patient
to
arthrodesis with
use
of
rigid
pedicle
screws
(
non
-
dynamic
)?
The trials below discussed the value of fusion as treat-
ment for spinal stenosis associated on one or two levels
with degenerative spondylolisthesis.
Herkowitz and Kurz
8
studied the isolated non-instru-
mented arthrodesis and showed that fusion produced less
radicular pain (in the lower limbs) and better clinical out-
come according to the surgeon’s assessment (
B
).
8
Bridwell
et al.
9
compared instrumented and non-instrumented fu-
sion techniques. Patients undergoing instrumented fusion
had less progression of spondylolisthesis and improved
walking ability (
B
).
9
Obtaining solid fusion was associa-
ted with subjective improvement. Both studies have me-
thodological limitations: the control group was small (
B
).
8,9
Fishgrund et al.
10,11
in a randomized trial done in 1997,
studied the effect of instrumentation on outcomes of spondy-
lolisthesis, either arthrodesed or not. The authors found
that the instrumentation increased the fusion rate but did
not improve clinical outcomes (
B
).
10,11
These studies have
provided conflicting evidence according to which instru-
mentation would produce significant clinical improvement.
Recommendation
Instrumentation is an option in the treatment of dege-
nerative spondylolisthesis to increase the chance of ob-
taining solid fusion and improve clinical outcomes (
B
).
I
s
the
use
of
bone
substitutes
such
as
BMP (
bone morphogenetic
protein
)
safe
and
effective
in
lumbosacral
arthrodesis
?
Regarding the rate of fusion, two studies
12-14
A compared
the use of osteoinductors (BMP) with iliac graft in pa-
tients with degenerative spondylolisthesis (single level),
treated by means of neural decompression and non-ins-
trumented intertransverse arthrodesis, with similar cli-
nical and radiographic results (
B
). However, there are
many publications and case reports on complications ari-
sing from the use of BMP, including bone resorption and
osteolysis, cage/graft migration, heterotopic ossification,
radiculitis, formation of specific antibodies and bruises.
15
Prospective and randomized studies are needed to eluci-
date the best clinical indications and safe dosages for the
use of osteoinductors (BMP) in lumbosacral spine.
Recommendation
Due to the small number of studies on osteoinductors
(BMP) and the high number of complications arising
from their use, it was not possible to recommend its rou-
tine use for the treatment of these patients.
W
hat
is
the most
appropriate
diagnostic
study
in
this
clinical
context
?
Plain radiographs in the standing position determine the
diagnosis and the percentage of slippage in degenerative
spondylolisthesis. Being available in most hospitals and
since it is not an invasive test, this is the first additional
test requested (
C
).
16,17
Plain radiographs of the spine are
effective to evaluate the bone structure of the spine and
should be performed in the standing position to be more
accurate in identifying the intervertebral disc height, lum-
bar lordosis and the degree of slippage between the
verte-
brae
. Plain radiographs in anteroposterior incidence also
allow assessment of the morphology of the articular fa-
cets. The lateral view also allows dynamic evaluation of
the stability of the spine with studies of lumbosacral spi-
ne in maximum flexion and extension (
C
).
22
Computed tomography is more sensitive and speci-
fic in identifying the narrowing of the spinal canal than
plain radiography, because it allows visualization of the
spinal canal in axial view. Myelography or CT myelo-
graphy is more specific than non-specific CT scans and
is important for the identification of spinal stenosis in
patients with degenerative spondylolisthesis and neu-
rologic symptoms. However, this is a test rarely used
because it is invasive and is associated with adverse ef-
fects – secondary to ionizing radiation and contrast in-
jection (
C
).
18,19
In the presence of symptomatic lumbar stenosis, the
most sensitive and specific radiologic examination is MRI,
as it enables the visualization of soft tissues in the spine.
MRI is the most accurate study to analyze the pathologi-
cal anatomy of the narrowing of the spinal canal – produ-
ced by prolapsed intervertebral disc, hypertrophy of the
ligamentum flavum
, zygapophyseal joint hypertrophy, and
vertebral slippage with intact vertebral arch (
C
).
20
Dyna-
mic myelography and CT myelography may be indica-
ted to elucidate cases where there is a lack of association
between symptoms and MR imaging for dynamic analy-
sis or the presence of bony component contributing to
the narrowing of the spinal canal. Another possibility for
such an indication is MRI contraindicated in patients
with pacemakers and claustrophobia. Sedation and open
MRI are options for performing the test in patients with
claustrophobia (
C
).
17-21