We have previously written an article on the range of motion following a lumbar fusion. The postoperative flexibility seems to be based primarily on the mobility prior to surgery. Of course, the more levels fused, and which levels fused, also contributes to the range of motion.
However, many joints are used to maintain the flexibility of our bodies. The hip joints and thoracic spine can aid in flexion even in which the entire lumbar spine is fused. This is an example of a very flexible patient of mine after a thoracolumbar fusion for scoliosis reconstruction.
This surgery straightened her spine and corrected her back and leg problems.
This surgery improved her lumbar curvature by about 10 degrees.
By using her hip flexors and other joints, she is able to nearly touch the floor despite having a T10-pelvis fusion.