Posterior lumbar spinal instrumented fusion is performed in the setting of instability in the spine. Patients with spinal trauma or conditions such as spondylolisthesis may benefit from this procedure. Surgery is performed from the back of the spine. Spinal implants such as screws and rods are often used to help stabilize the spine while the spinal bones heal and fuse together. Careful selection of patients who may benefit from this procedure is required before surgery can be successfully performed.