They added a spacer and had a discectomy.
I can understand your confusion. If you had a posterolateral spinal fusion then the intervertebral disc is not removed. Therefore this disc can bulge out later. If you have an intervertebral spinal fusion then the disc between the vertebrae is removed. In these cases the disc just above the fusion can bulge. Please discuss these two possibilities with your doctor (in your case probably the spacer has moved out). Hope this helps. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.
In 2008 I had spinal fusion with hardware L4/L5/S1 although the pain has continued and progressively gotten worse. The sciatic pain never went away I still have numbness and burning in my legs and feet. The nerve damage has gotten so bad that I'm taking at least 3200 mg of neuron tin a day and that doesn't keep the nerve spasms from happening at night. I can't remember he last time I've slept more the 3hrs a night. I could tell a year ago that a disc had herniated or a screw was working its way loose cause the stabbing pain in my behind and the weakness in my legs had become unbearable. I have been grinning and bearing this constant pain since 1994 so you can't tell me that I'm not a strong person. But I'm tired my PM had the audacity to tell me the only thing they could do was keep me comfortable well they have failed to do even that. I have had morphine pump inserted that almost killed me with a staph infection. I am not for any experimental treatments or recurring surgeries. At the end of my rope I was in so much pain yesterday I broke down and once agai accepted a narcotic for pain. See I have been on that zombie track don't want to go back there ever. Not looking forward to the next diagnoses. But praying for long lasting relief. New round MRI's here I come
Thanks for the comment and information.