Spondylolisthesis, spinal fusion, is a condition in which one of the bones of the spine (vertebrae) slips out of place onto the vertebra below it. If it slips too much, the bone might press on a nerve, causing pain. Spinal fusion is surgery to permanently connect two or more vertebrae in your spine, eliminating motion between them. It is a disease, often after the age of 60, which causes unbearable pain in the lumbar and lower limbs, gradually limited autonomy during walking. It intervenes with a micro decompression, but it becomes necessary to the positioning of a system is stabilization of pedicle screws and titanium bars. A surgery of this kind requires the latest surgical techniques and radiological threats. Our Equipe has been the first in Italy and one of the first in the world to use the system of neuro-navigation cord and, recently, a CT intraoperative type O-Arm, able to reduce to minimum the risks of the positioning of the prosthesis. The CT allows acquisition of high-resolution images directly in the operating position, and to control at each instant the use of the tools with respect to the 3D images of the patient, reaching an accuracy equal to 98%. The device thus allows a surgery "guided", a computerized control of all surgical gestures, particularly useful if you need to introduce systems for fixation of the spine, or when s' acts on the cervical spine area, home to vital structures. The patient leaves the hospital 2-3 days after surgery and resume normal activity. More than 25,000 spine surgeries have been done by our Group of Surgeon.