Hi Ross
Welcome to NeuroTalk

.
I am sorry to read about your problems.
The PN forum here (
https://www.neurotalk.org/peripheral-neuropathy/) is very active so if you post there other members will be able to offer you support and good ideas. Also, a thoracic syrinx can be associated with Chiari Malformation. You could search (
https://www.neurotalk.org/search.php) the Chiari forum here to see if there is anything which might help.
All the best.