Welcome to the CP forum! What most surgeons don't tell you is that fusion or for that matter, any back surgery done primarily to relieve pain is not going to work in most cases.
Back surgery, in my opinion and the opinions of many back surgeons is that it should only be done for structural problems or what are called mechanical problems. This usually means a spondylolysthesis ( slippage of one vertebra or more out of alignment with the rest) or other mechanical problem that can be fixed with surgery, such as stenosis ( where the nerves exiting the spinal cord or the spinal cord itself, are compressed at a specific level(s).
The tear in the outer portion of the disc can also be treated with another form of injection, in which they introduce a metal coil into the disc, and then heat it, so that the inner core of the disc is heated causing the entire disc to shrink and repair any tears.
If you have ddd, it is not a disease, per se, but rather the state of the discs drying out as we age. Anyone over the age of 18 has some degree of ddd.
The facet joint problems can be addressed with a rhizotomy, which is a burning of the nerves at the facet joint. In fact, before doing that, they can do specialized injections to see if numbing the nerves surrounding the facet joints improves pain levels. If that is positive, then a rhizotomy is usually the recommended treatment.
Anyway, before having any type of spinal surgery, you should get at least two opinions, and make sure that there aren't any other options available before going ahead with it. One thing that I learned the hard way was that the surgeon's opinion of a successful surgery was much different than what mine was.
The recovery from a spinal fusion is at least a year. And that is with no complications or other concerns. It is a long road, and difficult physically and mentally, so you really want to get at least one orthopedic spinal surgeon consult and one spinal neurosurgeon consult under your belt before deciding to undergo surgery.