Sorry to hear about you husband. There is a Trigeminal Neuralgia board here. Me and my daughter have it. I got mine from the damage of my TMJ. No one knows why my dd has it. We have gone thru lots of meds for it though. Right now she is on dilantin. Tegretol worked best for her but her body didnt process it right. The people on the TN board are great. There is a wonderful post on there for caregivers of TN. You are right it is rare. But not unheard of. I would see a neurosurgeon or neurologist that knows something about it. Good luck. Feel free to email me if you would like.

Crystalina