Anterior Lumbar (surgery performed through the abdomen) fusion surgery is performed to promote the growth of separate bones into one solid unit. This procedure is typically performed if there is a concern that the posterior procedure will not fuse. This procedure involves the placement of an interbody fusion device that is used to form a solid bridge of bone. Fusion does not occur immediately with surgery, but happens over time as your body builds bone at the surgery site. Because the goal of the procedure is to fuse the bones together, motion of the back may be limited in both up and down and side to side movements.