What is a spinal fusion of L4 L5 disk?

L4 and L5 are the last two vertebrae in your back before you hit your tailbone.

To fuse them, the surgeon will physically break the bones and put bone graft over them (bone graft can be from a bone bank or harvested from the patient's ribs or hip bone). When the bone heals, the graft will become part of the vertebrae, making the two vertebrae one solid bone.

Because bone takes about six months to heal, the surgeon will secure the fusion with titanium rods and screws to hold it in place until the fusion takes.

After the bone is fused, there is no need for the metal hardware. However, because the metal hardware is harmless, it won't be removed unless there are complications.