L5-S1 Grade II Spondylolisthesis
Patient Presents PMVA
The patient is a 21-year-old female who presents after a motor vehicle accident. She also has a 5-month history of low back pain, along with right leg pain and tingling.
She shows a right L5 sensory deficit, but no motor deficit.
Previously, she had physical therapy and facet epidurals to try to address her low back pain and leg pain with no pain relief.
Figure 1: Pre-op lateral x-ray showing Grade II spondylolistheis at L5-S1. There is also a Grade I spondylolisthesis at L4-L5. Lumbar kyphosis is 20º.
Figure 2: Pre-op PA x-ray
Figure 3: Pre-op flexion and extension x-rays. There is motion on flexion-extension.
Figure 4: Pre-op lateral MRI showing some compression at L5-S1.
Figure 5: Pre-op axial MRIs of L4-L5 (left) and L5- S1 (right) showing hyperactivity around the pars.
The patient was diagnosed with Grade II spondylolisthesis at L5-S1 and Grade I spondylolisthesis at L4-L5.
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The patient had an L4-S1 anterior-posterior decompression and instrumented spinal fusion.
An anterior-posterior approach was chosen because the patient was a young female, and I felt I could better reconstruct the anterior column, reduce her slip angle, and correct the pelvic incidence from an anterior-posterior approach, as compared to a posterior-only approach.
Figure 6: 6 weeks post-op lateral x-ray showing improved deformity. Note the reduced spondyloisthesis at L5-S1 especially. There is also a reduced slip angle and improved pelvic incidence. The sagittal imbalance has been corrected.
Figure 7: 6 weeks post-op PA x-ray
Figure 8: Pre-op (left) to post-op (right) lateral x-rays showing improved deformity.
The patient is two years post-op and is doing well. She’s back to her normal activities.
The operative management of spondylolisthesis may include a broad spectrum of approaches. Major areas of controversy in operative management of spondylolisthesis include the role of reduction of deformity, the role of interbody fixation, and the role of iliac fixation. This case exemplifies some important principles of care, and the result is a stable fixation with excellent restoration of lumbopelvic parameters.
The patient is a 21-year-old female with a grade 2 spondylolisthesis at L5-S1 and a grade one spondylolisthesis at L4-5. She became symptomatic after a motor vehicle accident and the pathology may be post-traumatic. The patient presents with significant deformity including a lumbosacral kyphosis of 20º. L4 is kyphotic, and the first horizontal vertebra in the sagittal plane is L1.
The surgeon's first decision in planning operative care is whether to gain reduction of the deformity. The deformity is partially reducible as demonstrated on the MRI scan better than extension views. An in situ fusion would result in significant sagittal plane malalignment, both regionally and globally.
The choice of a combined anterior and posterior approach facilitated an excellent reduction of the lumbosacral kyphosis and restoration of normal lumbopelvic measures. A posterior-only approach with or without interbody fixation would have been unlikely to result in as reliable a restoration of lumbopelvic balance.
Therefore, the surgical strategy of reduction of deformity and circumferential fusion with a combined anterior and posterior approach was well-guided.
The fusion from L4-S1 is a relatively short construct and should have limited stress on the S1 screws. However, in the setting of a significant reduction of deformity, the strain on the S1 screws is significantly increased. One potential mode of failure of this construct may be loosening or migration of the S1 screws. Extension of fixation to the ilium may be a reasonable option in this case to limit the possibility of loss of correction.
Overall, surgical strategies for the management of spondylolisthesis are characterized by significant variability. The goals of care in this case included a reduction of lumbosacral kyphosis and an improvement of regional and global balance. A combined anterior and posterior approach provided the most reliable technique for deformity reduction and maintenance of reduction.