My neurologist and a 2nd opinion neurologist brought in by her diagnosed the cause of my neuropathy as an autoimmune reaction to either spinal fusion surgery for stenosis, medication, anesthesia, or infections unrelated to the surgery. The autoimmune diagnosis opened up a treatment of IVIG with immunoglobulin to combat inflammation in the nerves. It led over time to less pain, greater strength and range of motion—all in combination with simultaneous physical therapy.