Spinal fusion of L4-L5 discs is a surgical procedure where the two vertebral segments are fused together to stop the motion at one segment. The surgery uses a bone graft to cause the two segments to grow together into a single bone, notes Spine-health.
The L4-L5 are two vertebrae located in the lowest part of the lumbar spine and are attached to discs, joints, nerves and soft tissues. The vertebrae help to support the upper body and allow for a range of motion in multiple directions. Due to the location in the lower lumbar spine, the L4-L5 segment is under heavy load, and combined with the wide range of motion is prone to injury, lower back pain, leg pain and degenerative changes, explains Spine-health.