Lumbar spinal fusion is a surgical procedure used to correct problems with the vertebrae of the lower spine/lower back. It is essentially a “welding” process, where the basic idea is to fuse together the painful vertebrae so that they heal into a single, solid bone.
By fusing the vertebrae together, motion is eliminated between vertebrae, also preventing the stretching of nerves and surrounding ligaments and muscles. The procedure is an option when motion is the source of pain, such as movement that occurs in a part of the spine that is arthritic. The theory is if the painful vertebrae do not move, they should not hurt.
Fusion will take away some spinal flexibility, but most spinal fusions involve only small segments of the spine and do not limit motion very much.