Objective: This retrospective review revealed the commonly compressed location and type of trigeminal nerve-compressing
vessel. Despite there being many studies about the intra-operative findings vis-a-vis microvascular decompression, none focus on ethnic Thai patients who can be different at the microanatomic level of vessels.
Materials and Methods: The study was a retrospective cohort design; with data collected from the medical records at
Srinagarind Hospital between 2010 and 2016 among patients who underwent microvascular decompression. Medical records
were reviewed as well as the video of the first 200 surgical operations.
Results: From among the 200 cases who underwent microvascular decompression, the authors found that the compressing vessel was most commonly the superior cerebellar artery (66.7%), followed by the petrosal vein (33%), the transverse pontine vein (12%), and other vessels (<5%). Fifty cases (25%) were compressed by more than one vessel. In 80% of the cases of multiple vessels compression, the superior cerebellar artery was the major compressive vessel. Only 4 cases were compressed by unknown small vessels. The other 4 cases had no compressing vessels.
Conclusion: The superior cerebellar artery is the cause of 66.7% of compressive idiopathic trigeminal neuralgia, followed by veins (27.8%), while 25% have co-compression by both an artery and a vein. In 80% of cases, the superior cerebellar artery is the major compressive vessel.

Keywords: Trigeminal neuralgia, Microvascular decompression, Intraoperative findings