I have heard this too. I know I have PN, but may have RSD in left foot and ankle. Had no correct DX of Anterior tibial tendon disfunction. MRI showed 5 years later, three torn ligaments-tendons, not healing right. Had two surgeries for ganglion cysts that the roots were going into my joint in the ankle. I now have two more, and can't have the surgery because of the PN or RSD. I am better however as I have tried B12 shots and use the pain patches. I also had no fall or injury to account for the injury to my foot and ankle to begin with. Just adding information here, about where this started on me. I hope and pray it never spreads. ginnie