I don't know what the fluid retention is from. I had the cervical spinal fusion in 2012 and ever since then my left leg has had major fluid retention. I've had numerous ultrasounds to check for blood clots (another just Sunday night at the ER because it hurts too). Dr says just watch your salt intake and wear compression socks but none of this is helping. Is it related to spinal fusion? What else could it be? I'm only 36 so it's driving me nuts!