Hi,
Thanks for writing in. A spine fusion is a surgery performed to link together individual segments, or vertebrae, within the spine. When there is a problem with the vertebrae (often a problem with the disc space), your doctor may recommend a spine fusion to eliminate the motion that occurs within that portion of the spine. By linking together the vertebrae, your doctor is trying to eliminate the source of your back problem.
What was the cause for surgery in your case? And since how long did you have this problem? There are several concerns with spine fusion surgery, but overall the procedure works very well for the vast majority of patients. The common problems after surgery are non-fusion of vertebrae, blood loss, infection, adjacent level degeneration and damage of spinal cord or nerves that exits from that part of the cord. It could most probably be damage to the nerves or thrombophlebitis in your case.
I would suggest that you visit your doctor and discuss the above mentioned possibilities, and treatment accordingly.
Best.