Review Question - QID 215635

This patient has central lumbar spinal stenosis at L3/4 and foraminal/extraforaminal stenosis at L5/S1 with evidence of a stable grade I spondylolisthesis at L4/L5 and has failed an appropriate trial of conservative management (3-6 months). Of the answer choices provided, a decompression through a left sided Wiltse paraspinal (posterolateral) approach at L5/S1 to address his radiculopathy would be an appropriate component of surgical intervention.

Lumbar spinal stenosis (LSS) is a degenerative condition in which changes in the discs, ligamentum flavum, and facet joints with aging cause narrowing of the spaces around the neurovascular structures of the spine. Narrowing of bony and/or soft tissues structures leads to compression of neural elements. Compression located centrally manifests as neurogenic claudication and is often caused by hypertrophied/buckling ligamentum flavum (as seen at L3/4 in the patient above). Lateral stenosis manifests as radiculopathy and may be caused by foraminal (far lateral, extraforaminal) disc herniation, facet arthropathy and osteophyte formation. While lumbar laminectomy is often the mainstay of surgical management in the absence of spondylolisthesis, it is important to consider the location of pathology at hand to ensure that a surgical procedure will predictably address the patient’s complaint(s). Central stenosis and/or lateral recess stenosis secondary to ligamentum flavum pathology can be addressed with a pedicle-to-pedicle decompression. When performing a laminectomy/laminotomy, there is a limit to the degree of foraminal decompression that can be achieved. In the setting of a far lateral disc herniation, such as in the patient above at L5/S1, an approach that allows access to the lateral aspect of the facet joints is necessary (unless a full facetectomy is performed, in which case this would also necessitate a fusion). Fusion procedures in the setting of lumbar spinal stenosis are often reserved for when there is concomitant instability (i.e., spondylolisthesis).

Pearson et al. 2012 performed a combined prospective randomized controlled trial and observational cohort study of intervertebral disc herniation (IDH) in association with the SPORT trial. IDH patients underwent either discectomy or nonoperative care and were analyzed according to treatment received. They reported that all analyzed subgroups improved significantly more with surgery than with nonoperative treatment. They concluded IDH patients who met their strict inclusion criteria improved more with surgery than with nonoperative treatment, regardless of specific characteristics. They do note, however, being married, without joint problems, and worsening symptom trend at baseline were associated with a greater treatment effect.

Lurie and Tomkins-Lane 2016 provide a review on the non-surgical and surgical management of lumbar spinal stenosis. The report options for non-surgical management include drugs, physiotherapy, spinal injections, lifestyle modification, and multidisciplinary rehabilitation, and they note that a systematic review concluded that there is insufficient evidence to recommend any specific type of non-surgical treatment. They also report that outcomes (leg pain and disability) seem to be better for surgery than for non-operative treatment, but the evidence is heterogeneous and often of limited quality.

Försth et al. performed an RTC to evaluate the efficacy of fusion surgery in addition to decompression surgery in patients who have lumbar spinal stenosis, with or without degenerative spondylolisthesis. They reported no significant difference between the groups in clinical outcome scores at 2 and 5 years postoperatively. They further reported that operating time was longer, the amount of bleeding was greater, and surgical costs were higher in the fusion group than in the decompression-alone group. They concluded that among patients with lumbar spinal stenosis, with or without degenerative spondylolisthesis, decompression surgery plus fusion surgery did not result in better clinical outcomes at 2 years and 5 years than did decompression surgery alone.

Figure A is flexion/extension views of the lumbar spine, which demonstrates a stable (no change in slippage between flexion and extension) grade I spondylolisthesis at L4/L5. Figure B represents an axial MRI image of L3/4 that demonstrates central and lateral recess stenosis. Figure C represents an axial MRI image of L5/S1 that demonstrates a left sided far lateral disc herniation.

Incorrect Answers:
Answers 1&3: A laminectomy/hemilaminotomy at L5/S1 would not allow adequate access to a far lateral disc herniation.
Answer 2: In the setting of a stable grade I spondylolisthesis, fusion is not indicated over decompression alone. Furthermore, fusion at this level would not address the patient's neurogenic claudication, as this pathology is secondary to central compression at L3/4 (which is not evident on the MRI at L4/5).
Answer 5: This patient has failed an appropriate trial of conservative management (3-6 months), surgical management should be pursued.