Lumbar fusion has been widely used for spinal disorders when conservative treatment has failed. However, a number of studies have reported that the rate of re-operation is high for lumbar fusion surgery. Swelling, atrophy or fat infiltration of the paraspinal muscles at the surgery site can cause weakness and pain. After fusion, the range of motion is constrained at the fused spine and might facilitate compensative movement of the adjacent levels and increase degeneration rate of the spine.