In a posterior approach to lumbar fusion, the surgeon makes an incision down the middle of the lower back. To see the vertebrae, the surgeon will pull back the muscles that surround the spine. In many cases, the surgeon will remove arthritic bone and other structures that may be putting pressure on spinal nerves. This is called a decompression, or laminectomy.
After the decompression, the surgeon will place graft material along the sides of the vertebrae to stimulate bone growth. This is called a posterolateral fusion. Titanium screws and rods are often used to provide immediate stability to the spine until a solid fusion has been achieved. These screws typically are not removed even after the bone graft has healed.