The best person in the position to explain the risks and procedures to you will be your surgeon, but I hope some of these pointers help.
Every surgical operation has its risks depending on your age or if you have other comorbid conditions (hypertension, diabetes, stroke, etc). Complications include difficulty of breathing, heart problems, kidney problems during or after the operation, though these can be minimized with proper pre-operation evaluation (usually by an internist, or cardiologist).
Operation to the spine is also very tedious and technical and the more common complication would include infection of the surgical site. The plates or cage if not properly secured can cause further problems like nerve impingement.
As I've written, you should discuss all of these risks with your surgeon before you sign the consent form.
I hope your surgery will be uneventful and successful! God bless.
THANKS FOR YOUR REPLY. IT IS VERY HELPFUL MY MAIN WORRY IS MY AGE! I AM 68 SOON. MY SURGEON HAS TOLD ME OF MOST OF THE RISKS, BUT NOT THE POSSIBILITY OF THE CAGE BEING FITTED LOOSELY. ARE YOU IN A POSITION TO TELL ME IF YOU WOULD CONSIDER IT YOURSELF? BUT MAYBY THAT IS AN UNFAIR QUESTION! ANYWAY THANK YOU SO MUCH FOR YOUR REPLY BEST WISHES BOYCEE.