Hi, could be a couple of things going on, i am wondering if you have had a nerve conduction test for carpal tunnel and have you had a MRI on your cervical spine, long term use of the drug allopurinol has been known cause peripheral neuropathy in a small percentage of some people, but after the drug is ceased symptoms improve.
Have they tried steriod injections to reduce the inflamation ? another thought is the use of splints when sleeping to see if it is comming from compressed median nerves, just seems strange that if the uric acid is well controlled but your symptoms haven't improved, what ongoing treatment has that neuro recommended for your terrible pain ?
best of luck
Aussie