--how was the small fiber neuropathy diagnosed? Was there specialized autonomic testing (such as tilt table), sudomotor axon reflex testing, qualitative sensory testing, or skin biopsy?

The reasons for my asking is that many of your symptoms might well be explained by the spinal problems you've had. It's often very difficult to distinguish between nerve problems with the spinal cord or nerve roots and problems with the more peripheral nerves, as the symptoms may be exactly the same. This is why investigation into the genesis of neurological symptoms is often long, costly, and very much a process of elimination. But I'd be wary of a small-fiber neuropathy diagnosis without clearly abnormal results from such specialized small fiber testing, especially inasmuch as you have documented spinal issues.