Spinal fusion is an operation that is conducted to limit the mobility of adjacent vertebrae in the spine. The most common reason for performing a spinal fusion is low back pain caused by painful motion of the vertebrae. The goal of a spine fusion is to eliminate the motion of the offending vertebrae. This reduces any pain caused by motion. ,

Degenerative disc disease, spondylolysis and other degenerative spinal conditions can cause this abnormal and painful motion.  In addition, a spinal fusion may be indicated for any condition that causes excessive instability of the spine, such as fractures, infections, tumors, and congenital spinal deformities.

There are two main types of spinal fusion: posterolateral fusion and interbody fusion. In a posterolateral fusion a graft is inserted to create a bony bridge between two vertebrae.  In a posterolateral fusion procedure, which is much more common, involves placing screws to bolt two or more vertebrae together into a rigid position.