This middle aged male had an instability in the lower back with backward and forward bending x-rays showing movement [instability] with spondylolisthesis [forward shifting of the vertebra]. This was causing back and leg pain. The treatment was surgical fusion of the unstable segment, with bone graft between the vertebral bodies and also posteriorly, with spinal fixation to reduce the deformity back to normal alignment. The x-rays show fusion [milky white bone] between the vertebrae as well as on either side.

 
  Spondylolisthesis with forward flexion instability

AP [front back] view showing fusion in between and on either side of the vertebrae.  
Reduction of the slip of bone, with fusion seen between the vertebral bodies. Internal fixation with metallic devices.