A paper in the NIH library describing surgical treatment for TN can be found with the link below. It is rather lengthy and very thorough. The authors claim that 85% of TN cases are caused by an artery or vein rubbing on the trigeminal nerve. I have copied the conclusion to the article below. I have discussed this procedure with a surgeon at OHSU but, at the moment, prefer medicinal treatment.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9452382/#:~:text=Since%20then%2C%20many%20studies%20have,vessel%20from%20the%20trigeminal%20nerve.
CONCLUSION
The effect of MVD on TN has already been established. However, more advanced research is needed for clearer surgical indications, management of culprit vessels, and durability of the decompression materials. In the future, along with the continuous study on the pathophysiology of TN, a new MVD technique that is safer and can increase the cure rate should be developed.