Decompression with or without Fusion in Degenerative Lumbar Spondylolisthesis
- Controversy remains whether fusion is beneficial in addition to decompression for patients with lumbar spondylolisthesis.
- Multi-center, randomized, open-label, parallel group, noninferiority trial.
- Ages 18-80 with neurogenic claudication or radicular pain that had not responded to 3 months of conservative management.
- MRI evidence of spinal stenosis and degenerative spondylolisthesis at the stenotic level of at least 3 mm.
- Excluded if had foraminal stenosis of grade 3 or higher (i.e. deformed nerve root in foramen), previous surgery, or thoracolumbar fracture.
- Patients assigned 1:1 - decompression versus decompression with instrumented fusion.
- For those assigned to decompression, a posterior decompression that preserved the midline structures was used.
- Fusion technique and implants used at discretion of surgeon.
- Fusion determined by computed tomography at 2 years.
- Primary outcome: reduction of Oswestry Disability Index by 30% or greater from baseline at 2 years post-operatively, assessed for non-inferiority of decompression alone by difference within 15 percentage points.
- 267 patients randomized, 134 to decompression alone, 133 to decompression with instrumented fusion.
- Primary endpoint: 71.4% in decompression alone and 72.9% in the decompression and fusion groups had a reduction of at least 30% in the ODI score, indicating noninferiority of decompression alone.
- Secondary subgroup analyses: mean duration of surgery, mean length of hospital stay and dural tears were all greater in the instrumented fusion group.
- Rates of re-operation were not significantly different between the two groups.
- Variation in surgical approach: bilateral vs. unilateral decompression, interbody cage use.
- 15 percentage point difference was chosen empirically as no accepted margin for noninferiority exists in literature.
- Patients were included regardless of the grade of slippage above 3mm and regardless of the result of radiographs to detect dynamic slippage of vertebral bodies.
- Decompression alone was noninferior to decompression and fusion with respect to the percentage of patients who had a reduction of at least 30% in the ODI score at 2 years after surgery within a margin of 15 percentage points lower.
This summary was published in Nov. 2021.