Posterior lumbar interbody fusion (PLIF) is a surgical procedure performed to treat conditions such as degenerative disc disease, disc herniation, or spinal instability in the lower back. The procedure involves making an incision in the back, exposing the affected vertebrae. The damaged disc is removed, and bone graft or a cage filled with bone graft material is inserted into the disc space. This promotes fusion between the adjacent vertebrae, stabilizing the spine. Additional hardware like screws, rods, or plates may be used to provide stability during the fusion process. The procedure aims to relieve pain, restore spinal stability, and prevent further degeneration of the affected segment.