Lumbar fusion is a surgical procedure designed to join two or more vertebrae in the lower back, eliminating motion between them. It is commonly performed to relieve chronic back pain caused by conditions such as degenerative disc disease, spinal instability, spondylolisthesis, or severe spinal deformities. The procedure involves using bone grafts, metal screws, and rods to stabilize the spine, allowing the bones to fuse over time. Recovery typically includes physical therapy and gradual return to daily activities, with the goal of reducing pain and improving spinal stability.