If the spine is unstable and puts extensive stress on the facet joints, or if there is significant pain originating from the disc or other structures, the spine may still need to be fused. Fortunately, minimally invasive fusion techniques have been developed, which allow for less pain and quicker healing times for the patient, this is known as endoscopic fusion of the spine. Endoscopic fusion treats degenerative spinal disease and instability that cause back and leg pain. In most cases an endoscopic discectomy is necessary. The damaged disc is removed through the endoscope, and spinal endplates are prepared for fusion under direct visualization. Endoscopic fusion is performed under general anesthetic to facilitate the insertion of spinal instrumentation. Patients are usually discharged on the same day as the surgery, and have much less pain and a quicker recovery than those who undergo traditional spinal fusion surgery. Patients can usually begin physical therapy within a month after fusion surgery.