Laminectomy alone vs laminectomy with posterior fusion in lumbar spinal stenosis: The role of instability

Figure 1 Imaging of degenerative spondylolisthesis (Wiltse type III) at L4-L5. A: Sagittal T2-weighted magnetic resonance imaging demonstrating anterolisthesis of L4 over L5 with associated disc degeneration and loss of disc height; B: Axial T2-weighted magnetic resonance imaging at the L4-L5 level showing severe central canal stenosis and degenerative facet changes; C: Lateral radiograph clearly showing the anterior slip.

Figure 2 Imaging examples of degenerative changes contributing to central canal stenosis. A: Axial T2-weighted magnetic resonance imaging (MRI) from a 66-year-old male with unilateral facet joint hypertrophy (white arrow) narrowing the central canal; B: Sagittal T2-weighted MRI from a 49-year-old male showing ligamentum flavum thickening and buckling into the spinal canal (white arrows); C: Axial T2-weighted MRI from a 75-year-old male with lateral recess stenosis; D: Axial T2-weighted MRI from an 82-year-old male with central canal stenosis due to a combination of bilateral facet joint hypertrophy, ligamentum flavum thickening, and a central disc herniation.

Figure 3 Postoperative lumbar spinal fusion with pedicle screw instrumentation. Lateral (left) and anteroposterior (right) plain radiographs demonstrate solid fixation at the instrumented level with bilateral pedicle screws and connecting rods.