Back and Leg Pain in a 47-year-old
The patient is a 47-year-old female with back and right leg pain. She had to stop working two years ago due to inability to sit for more than 15 minutes. She is taking oral morphine and hydrocodone for pain control.
Her low back pain is exacerbated with forward flexion. The L5-S1 facets are tender to palpation. Motor strength is 5/5. Reflexes are 2+ at the knees and 1+ at the ankles. Sensation is decreased in dorsum of the right foot.
An epidural steroid injection at L5-S1 on the right provided temporary (one week) relief of right radicular leg pain. Physical therapy worsened her back pain.
Figure 1A. Sagittal T2-weighted MRI reveals L5-S1 spondylolisthesis and degenerative disc disease at L5-S1. There is mild disc bulge at L4-L5.
Figure 1B. Axial MRI T2-weighted images reveal spondylolysis at L5-S1.
Figure 1C. Midline sagittal CT scan again demonstrates the L5-S1 spondylolisthesis.
Figure 1D. Paramedian sagittal CT scan demonstrates the spondylolysis at L5-S1.
Figure 2A, Flexion
Figure 2B. Extension
Figure 2C. Standing
Lumbar discography was performed; results:
- L4-L5 and L5-S1 concordant pain
- L3-L4 painless
L5-S1 spondylolysis, with grade 2 spondylolisthesis, degenerative disc disease at L4-L5 (mild) and at L5-S1 (severe) in a patient with back pain and right leg radiculopathy.
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Stage 1: L5-S1 anterior lumbar interbody fusion (ALIF) was performed and the interbody space was serially dilated to restore disc space height. A 16 mm carbon fiber cage with bone morphogenetic protein (BMP) was placed in the interbody space and an anterior plate was applied. The screws pulled the listhesis into alignment as they were tightened. Subsequently, an L4-L5 ALIF was also performed, since the discogram was positive at that level.
Stage 2: a mini-open right-side approach allowed for L4-L5-S1 pedicle screw fixation and posterolateral fusion and a right L5-S1 decompression. In cases of spondylolysis, I prefer to backup my anterior construct with at least a unilateral posterior pedicle screw fixation to prevent anterior plate and graft failure.
Figure 3A. Postoperative, flexion x-ray
Figure 3B. Postoperative, extension x-ray
The patient returned to the clinic 6 months after surgery and reported her right leg radiculopathy was completely resolved. She still had some back pain but was able to decrease her preoperative narcotic dose in half. She is applying for disability.
This case presentation of a 47-year-old female with back and right leg pain accentuates the difficulty spine surgeons encounter with treatment of lumbar pathology. It further exemplifies the potential of heterogeneity of pathology for which patients present with similar clinical scenarios.
In this case, an individual presents with both a combination of back and leg pain. It is important to distinguish between the degree of axial back pain and the degree of radicular or nerve symptoms. This can help define the goals of the surgical treatment. In this case, the patient underwent an epidural steroid injection with temporary relief for one week. This I believe is a good prognostic indicator for surgery in that she was able to have some degree of relief with the steroid and most likely suggests a significant radicular component to her pain.
Review of her imaging studies shows a complete collapse of the L5-S1 disc space, as well as desiccation of her L4-L5 and L3-L4 disc spaces. There is a capacious spinal canal with some degree of lateral recess and foraminal stenosis. I do agree with the author in that obtaining CT scans can be very helpful. This illustrates complete collapse of the L5-S1 interspace with osseous remodeling of the sacrum. Flexion-extension lumbar films were also obtained which are extremely helpful in this population. Unfortunately, the patient did not have much voluntary motion with these flexion-extension films. Despite that there does not appear to have any motion at the L4-L5 disc space, as well as the L5-S1 interspace. One criticism of the film's technique would be that they were done with the patient in a sitting position (determined from her femur being at a 90-degree angle from her pelvis). It is much more advantageous to obtain standing x-rays as such to understand the patient's overall global sagittal balance, as well as coronal balance. In addition, this shows the patient with their weight on the spine. Therefore, in patients with greater than grade I spondylolisthesis, obtain 36" cassette imaging may be beneficial.
The authors had the additional information from a lumbar discogram. I am not exactly sure I would have obtained a discogram in this patient, since the information may be more confusing than helpful. Further, Eugene Carragee has shown us that there are numerous psychosocial factors that can cloud the interpretation of these results. In addition, we must also remember that discography is a subjective test for the patient and discographer, which can further cloud interpretations. Lastly, there are some suggestions that the discogram in itself can result in propagation of disc desiccation, as well as lateral disc herniations, at the site of the annuals' puncture sites.
The difficulty with spinal surgery is to understand the goals of the procedure. We must discern the degree of axial back pain versus radicular symptoms since this will designate our treatment. If this patient presented with the predominance of radicular symptoms and minimal back pain, one option may be to proceed with a decompression and fusion simply of the L5-S1 interspace. Either with a TLIF or posterior lateral instrumented fusion.
On the other hand, if the surgeon decides the symptoms are mostly low back pain and proceeds with an axial back pain procedure, the goal of the procedure would be a complete decompression of the pain generator (disc). In this case, I would have proceeded with a two-level anterior fusion at L4-L5 and L5-S1. In this case, I am not sure that the addition of an anterior plate provides much stability when a posterior pedicle screw construct is also placed.
The author is to be commended in this case in that he was able to provide significant opening and distraction of the L5-S1 interspace. This can be quite difficult in these chronic spondylolisthesis cases due to ankylosing of the joint. In fact, the surgeon returned the disc to its natural height by placing a 16 mm cage. One should be cautious in that over distraction the disc at the L5-S1 interspace can result in neurogenic pain presumable due to traction of the dorsal root ganglion. Therefore, with complete disc space collapse either a 12 mm or possibly with a 14 mm graft typically will suffice. In the discussion, I was unable to discern whether the author proceeded with a foraminotomy at the L5-S1 disc space during the posterior procedure. This is typically not necessary since there is an excellent indirect decompression of the neural foramina due to the reduction of the spondylolisthesis.
In summary, this patient presented with a component of both lumbar axial and leg pain and underwent an anterior-posterior decompression and arthrodesis procedure. As we see from this case, there are numerous strategies a surgeon can take in order to resolve the patient's clinical symptoms. In this case, the author chose to proceed with an anterior-posterior procedure and appears to have quite a successful clinical outcome.
It is important to remember that there are several different types of spondylolisthesis. For example, it is very unusual to have a degenerative spondylolisthesis at the L5-S1 and the great majority of these are lytic spondylolistheses due to a pars defect. At L5-S1 the coronal orientation of the facet joints prevents a translation of the L5 body on S1, and therefore to get a slip there must be a fracture. This is directly opposite to an L4-L5 spondylolisthesis where in a L4-L5 there is a very high likelihood, particularly in a woman, of having a degenerative spondylolisthesis due to ligament laxity and the sagittal orientation of the facets allowing anterior translation.
Further, plain films and particularly flexion-extension films can be of help and detect any instability which may alter surgical planning. It is not uncommon for the patient to have a stiffened segment at L5-S1 due to spondylosis and develop a degenerative spondylolisthesis proximally at L4-L5. To get the greatest understanding of the spinal dynamics, lumbar flexion-extension should be performed with the patient standing, as well -- it is also nice to have the heads of the femur in the image. Therefore, the pelvic incidence (PI) can be calculated. This measurement (PI) has been shown to have a significant correlation with the progression of high grade spondylolistheses. Lastly, as the author did in this case, the surgical technique should be directed at the patient's clinical symptoms in order to maximize the clinical outcome.