Thanks for writing in.
Yes trigeminal nerve can get compressed by thickened fibrous tissue of the scar. However nothing can be said for sure without an MRI exam. Do let us know the results of your test.
Forgot to mention, you may also want to consider an infection from the shunt.
Has your doc considered giving you Accyclovir for a virus (such as the "cold sore virus"- HSV-1 or the virus causing chickenpox)? They can lay dormant in the trigeminal nerve.
I, too, had brain surgery in 2003 and am a 37,F who will be having an MRA/MRI soon and also hope for answers!