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Posterolateral versus Posterior Interbody Fusion in
Isthmic Spondylolisthesis
Majid Reza Farrokhi, MD; Abdolkarim Rahmanian, MD; Mohammad Sadegh Masoudi, MD*
Shiraz Neurosciences Research Center, Neurosurgery Department, Shiraz University of Medical Sciences, Shiraz, Iran
Introduction
Results
Spondylolisthesis is a heterogeneous disorder characterised
by subluxation of a vertebral body over another in sagittal
plane. Its most common form is isthmic spondylolisthesis
(IS).
Fusion in PLIF group was significantly better than PLF group
(P=0.012).
Improvement in low back pain was statistically more
significant in PLF group (P=0.001).
The nerve root deficits and leg pains involve foraminal
stenosis caused by a combination of fibrocartilaginous mass
at the isthmic defect, disc and osteophyte of the slipped
body.
Incidence of neurogenic claudication was significantly lower in
PLF group (P=0.004).
In PLF group, there was no significant correlation between slip
Meyerding grade and disc space height, radicular pain, and
low back pain.
Instrument-assisted posterolateral fusion (PLF) and
posterior lumbar interbody fusion (PLIF) are used as two
common techniques for the treatment of IS.
There was no significant difference in
complications at the 1-year follow-up period.
This study aims to compare clinical outcomes of PLF with
posterior instrumentation and PLIF with posterior
instrumentation in the treatment of grades I and II of IS.
postoperative
Intraoperative blood loss in PLIF was significantly more than
PLF procedure (P=0.04).
Materials and Methods
Parameter
We performed a randomized prospective study in which 80
patients out of total of 85 patients with lumbar IS , 18 men
and 62 women aged 18-65, were eligible to participate and
were randomly allocated to one of 2 groups: PLF with
posterior instrumentation (n=40) or PLIF with posterior
instrumentation (n=40). A 1-year follow-up period was
planned from March 2010 to March 2011.
Groups
Mean Rank
PLF
46.19
Mean ± SD P value
6.59±1.79
Radicular Pain
Parameter
Reduction in
Low Back Pain
Fusion was performed by using bone chips, achieved from
the resected lamina, mixed with synthetic bone substitute
granules.
0.138
PLIF
38.44
6.02±1.83
Groups
Mean Rank
Mean ± SD
PLF
51.00
25.34±9.36
P value
0.001
PLIF
33.11
17.10±12.98
Inclusion Criteria
Isthmic spondylolisthesis
No previous spine operation
Age between 18 and 65
Failed conservative therapy
Exclusion Criteria
Non-isthmic spondylolisthesis
Need to perform discectomy in PLF group
Infection
Generalized bone disease
Radiological Evaluation
Static and functional lumbar spine plain X-rays, four
views: anteroposterior (AP), lateral, right and left
obliques, in which features relevant to spondylolisthesis,
including percentage of subluxation, severity of slip,
slippage angle, and height of intervertebral disc space
were evaluated.
Successful fusion was defined as the integrated ossification
at the fusion bed without motion in a dynamic graph.
Statistical Analysis
The Oswestry low back pain disability (OLBP) scale and
visual analogue scale (VAS) were used to evaluate the
quality of life (QOL) and pain, respectively. The Fisher
exact test was used to evaluate fusion rate and MannWhitney U-test was used to compare categorical data.
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Parameter
Groups
Good Fusion
Bad Fusion
PLF
66.7%
33.3%
Fusion
P value
0.012
PLIF
89.1%
10.9%
Discussion
Our findings suggest that PLF with posterior
instrumentation provides better clinical outcomes
compared to PLIF with posterior instrumentation.
Conclusion
Improvement of low back pain in PLF group was more
significant than PLIF group in our study.
The number of the patients who had complaints of
neurogenic claudication 1 year after the operation was
significantly more in PLIF group with posterior
instrumentation than PLF.
It seems that fusion alone is not sufficient for the
reduction of low back pain. More manipulation of osseous
tissue, end plates, dura, and neural structures in PLIF is
the main cause of more LBP in this procedure compared
with PLF, in spite of better fusion rate in PLIF.
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Compared with PLIF, the improvement
in low back pain and QOL was better in
patients who underwent PLF with
posterior instrumentation.
PLF with posterior instrumentation is
recommended in patients with IS
because this procedure is simple, with
less neurological deficits, less blood loss,
and better clinical outcomes.
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