Sorry to hear about your latest surgery and hope that it doesn't keep you from enjoying your vacation.
I'm no expert like some of the people here but assuming your doctor told you no jerky movements at all, here's a list of what to avoid.
At Universal Studios, I would not ride The Simpsons, Rip Ride Rocket, Disaster, Shrek, Jimmy Neutron and maybe the Mummy. Now, you may be ok on the Mummy since I don't remember it being jerky, just fast. You can also ask for stationary seating at Jimmy Neutron. Not so sure about Shrek but I would imagine so. MIB has some minor spining if you're ok with that.
At Islands of Adventure, I would not ride The Hulk, Dr.Doom's Fearfall and Dragon's Challenge. Cat in the Hat has minor spinning, Storm Force Accelatron is a "Tea Cups" ride, all spinning. Spiderman has some spinning and a simulated fall but not jerky. Popeye can have a bump or two when the Water Barge hits the edges same goes for Dudley-Do-Rights which has a drop at the end. Jurrasic Park River Adventure also has a drop, if you're ok with a fast drop then these will be ok too. Finally, Harry Potter and the Forbidden Journey I hear is very smooth, there is a couple of parts that you're on your back for a few seconds but it's not jerky at all.
Hope this helps and I wish you a speedy recovery.
