Hi Desi-
Regarding the fusion... I know many people walk around with herniated disc and don't get them fused. I think it depends on the degree of impingement it is causing on the cord and nerves etc. Many herniated disc can cause neurological impairments and sever pain. I would talk to your neuro and see what they recommend at this point. If it is a budging disc then it can be dealt sometimes with physical therapy.
If you do have to have surgery later on remember to have a SG block done prior to so you can help prevent a spread.
I know there are members here that have had spinal surgery that have RSD that can offer you better advise... I know surgery and RSD are a complicated issue..
I wish I could offer you more advice. You could go to the spinal forum http://neurotalk.psychcentral.com/forumdisplay.php?f=22 they would have loads of information on the useful site sticky for you there on herniated disc and surgery etc.
Take care and be sure to look into your best interest with spinal surgery and RSD...
Many Hugs
Dawn