The lumbar spine has a steel nail can bend from person to person, as follows: 1, for lumbar spine fracture surgery, steel nail is to fix the repositioned vertebral body, the fracture completely healed can be carried out after a small bending activities or exercise. If a large number of bending activities are carried out prematurely, it may cause the internal fixed steel nail to break, loosen or fall off; 2. For lumbar spine slippage, disc herniation, lumbar spine instability surgery, the steel nail is to fix the intervertebral space, the intervertebral space is completely healed to reach the bony fusion can be bending activities, but should avoid long-term excessive activities.