I'm so sorry that you are in so much pain and have suffered for so long.
Has your doctor suggested physical therapy to you? It would be an excellent idea to try a round of physical therapy to learn how to properly strengthen you core muscles.
The cores are vitally important for good support of your spine, and can be helpful in healing a torn disc.
What type of spinal injections have been suggested to you?
Where they nerve block?
Where they epidural?
They can work quite well to ease pain and relieve the inflammation and potentially heal the disc.
If the pain is from the torn disc and fragments of the disc are pressing on the nerves or the disc itself are pressing on the spine, the injections may relieve your pain.
If injections are being done to relieve pain only, then they do not work for long.
Some people have relief for only a few weeks , others, months and still others need them twice a year.
There are also some people that have had 1 injection at it was enough to relieve the pain and inflammation and heal the disc.
It sounds like your neurosurgeon is saying you need a fusion. Did he/she tell you why?
There are many, many people that have had successful lumbar fusions and go on with their life with very little, if any, loss of of mobility.
Did your spine surgeon say what kind of fusion he/she would do and how many levels?
I would suggest, though, that before you make any decisions about surgery, you seek out several other opinions before making a decision.
One should always have more than one opinion when ever possible before agreeing to surgery.
You should get opinions from an orthopedic surgeon that specializes in spines as well as another neurosurgeon.
Good luck and let us know how you are doing
Fran