L4-L5 Grade II Spondylolisthesis: Failed Laser Spine Surgery
The patient is a 52-year-old female with a long-standing history of low back pain (30%) and radicular pain (70%). She initially presented with a Grade I spondylolisthesis, and she received extensive medical treatment, which failed to control her pain. She then had “laser” surgical decompression, but her pain persists and her spondylolisthesis has progressed to a Grade II.
The patient has 5/5 motor strength in bilateral lower extremities. She has no sensory deficits, but she does have an antalgic gait.
Previously, the patient had undergone physical therapy. She has also tried NSAIDs, muscle relaxants, and a narcotic pain medication.
The patient also had an epidural as well as facet injections with no pain relief. She subsequently underwent surgical “laser” decompression (hemilaminotomy/discectomy) with only temporary improvement of leg pain followed by significant worsening of back pain and leg pain.
Figure 1A: Sagittal MRI before “laser” surgery
Figure 1B: Sagittal MRI after “laser” surgery
Figure 2: Extension (left) and flexion (right) x-rays after “laser” surgery
Figure 3: Sagittal CT scan (left) and axial CT scan (right) after “laser” surgical decompression
The patient was diagnosed with L4-L5 Grade II spondylolisthesis.
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The patient had a minimally invasive lateral retroperitoneal transpsoas lumbar interbody fusion at L4-L5 with L4-L5 percutaneous pedicle screw fixation.
The procedure was first performed in the lateral position. A PEEK interbody graft (18 mm × 55 mm × 8 mm with 10° of lordosis) filled with allograft (HAA, triphosphate calcium, and 0.7 mg rhBMP-2) was used. Careful preservation of the anterior longitudinal ligament and an intentional undersizing of the interbody graft were performed to allow for final spondylolisthesis reduction posteriorly.
The patient was then placed in the prone position to allow for bilateral L4-L5 percutaneous pedicle screw placement. The residual spondylolisthesis was then sequentially reduced, and the screws were secured with rods to achieve rigid fixation and to maintain reduction.
Figure 4: Intra-operative fluoroscopy image after lateral interbody fusion and partial deformity reduction followed by percutaneous pedicle screw placement
Figure 5: Intra-operative fluoroscopy image after final percutaneous pedicle screw placement and sequential spondylolisthesis reduction
Figure 6: Post-op sagittal CT scan (left) and coronal CT scan (right) showing adequate spondylolisthesis reduction
Figure 7: Post-op axial CT scans showing cage and pedicle screw placement
Figure 8: Post-op 2-year follow-up upright radiograph showing final construct with evidence of solid fusion and sustained spondylolisthesis reduction
At the 2-year follow-up, the patient has improvement of back pain and leg pain and is able to perform her normal daily activities with discontinuation of narcotics.
After failing reasonable medical management in the first place, the patient was properly indicated for surgical treatment. The initial Grade I listhesis is assumed to be of the isthmic subtype based on the appearance of the axial CT presented in Figure 3. This is significantly less common at L4-L5 than L5-S1, but it can be seen at any lumbar level, even multiple levels.
As an aside, if it had been a more typical degenerative spondylolisthesis, and certain clinical and anatomic conditions existed, a decompression alone would have been appropriate despite the listhesis. In my opinion (practice), someone with predominant leg pain, advanced disc degeneration, little or no change in listhesis between supine and standing x-rays, reasonably intact facets with coronal orientation, and minimal facet effusions on axial T2-weighted MRIs, has the option of decompression without a fusion. But the decompression must be done well while preserving the integrity of the facets. And the patient must accept the possibility of iatrogenic instability and the need for a subsequent fusion. I am not aware of any credible scientific data that support the role of percutaneous "laser" decompression for this hypothetical situation.
Now in the case of an isthmus listhesis, the treatment ought to include an effective decompression and fusion. That is especially the case after an initial failed "surgery." The options are many and will vary in the hands of a given surgeon. But the key to a happy outcome is an anatomically effective decompression and a solid arthrodesis. Reducing the lishtesis is optional, although it is a by-product of an interbody procedure, be it anterior, lateral or posterior.
The method chosen here accomplished all of the treatment principles very well. Personally, I would have elected to do this as an open posterior procedure +/- a PLIF combined with a posterolateral fusion.
If I had felt compelled to do an anterior interbody procedure for such a Grade II listhesis, I would have preferred a mini-open ALIF. The decision to undertake an XLIF at L4-L5 must account for the surgeon's facility with the technique, as well as the increased risk of an acquired femoral nerve palsy.
As a final thought, I would offer a comment about the chosen method of anterior "bone grafting." There is a huge body of basic and clinical science that has led to the approval of BMP-2 use in anterior interbody lumbar fusions. And even though the "on-label" application is to be with a specific interbody cage, the biology of action is the same independent of the cage type. There is no rationale for adding the expense of other bulking agents for an anterior interbody application. This increases the cost of the procedure without adding clinical efficacy. We have a responsibility to make wise and informed choices about resource use in this day and time.
Well done. It is pleasing that the patient's second procedure served her well.