You might want to check out the Facial Pain Association, fpa-support.org. There is a lot of info on Trigeminal Neuralgia (TN) on that site. MVD (Micro-vascular Decompression) surgery is used in "typical" TN to move/pad a vein that is wrapped around the trigeminal nerve and rubbing against the nerve. In a large number of TN cases (typical/TN1), the vein irritates the never, causing the facial pain.

With MS, the normal cause of the facial pain is related to plaques in the brain that irritate the trigeminal nerve. An MRI is required to rule out a vein compression, tumors etc. There is a "Trigeminal Protocol MRI" using very thin slices to attempt to see vein compression; however, it is not 100% accurate.

If meds no longer work in controlling the TN, the surgical procedures I listed in my post can be considered. My post is an attempt to find more people with actual experience with Balloon Compression etc. for TN with MS.