There are arguments pro and con the surgery. I had debilitating crushed discs in both the cervical and lumbar region with level ten pain so bad I couldn't move without a walker, refused the surgery, and followed the excellent advice provided by rehabilitation specialists, and after a long period returned to normality.
Get a second opinion from another doctor. Why can't you have MRI? That should have been done before fusion. Your doc sounds like a quac. Anything that relates to your spine should be done by a neurosurgeon. Never use a orthopedic doc....they are good for hips, shoulders etc., but not spines. Have you asked about going to physical therapy?