fusion /fyo̅o̅″zhən/ [L, fusio, outpouring] , 1. the joining into a single entity, as in optic fusion.2. See ankylosis. 3. the surgical joining of two or more vertebrae, performed to stabilize a segment of the spinal column after severe trauma, herniation of a disk, or degenerative disease. Under general anesthesia the cartilage pads are removed from between the posterior parts of the involved vertebrae. Bone chips are cut from one of the patient’s iliac crests and inserted in place of the cartilage, fusing the articulating surfaces into one segment of bone. 4. (in psychiatry) the tendency of two people who are experiencing an intense emotion to unite.
