Abstract Details

Title The Anatomy of Vascular Compression in Trigeminal Neuralgia

Topic Peripheral Nerve

Presentation(s) P07 - (-)

Poster/Presentation
Number 051

Objective

Background BACKGROUND: The etiology of TN is unclear but vascular (arterial and venous) compression of the trigeminal nerve roots is thought to be causal in many cases. The theoretical underpinning to the vascular compression hypothesis is primarily based on hypotheses presented by Dandy (1934) and Jannetta (1980) proposing age-related "arterial elongation" and "brain sagging." Reported success rates for microvascular decompression surgery (MVD) vary widely from 30%-97%.

Design/Methods DESIGN/METHODS: We searched the literature using the keywords: "trigeminal neuralgia," "microvascular decompression," "arterial compression," "venous compression," and "neurovascular compression."

Results RESULTS: The vessels most often implicated in TN are the superior cerebellar artery, anterior and posterior inferior cerebellar arteries, and superior petrosal vein including several tributaries. Jannetta's theory of "brain sagging" was proposed to explain the anatomical positions of these vessels, yet if this was valid TN should occur bilaterally. Bilateral TN is seen in <5% of cases and TN is actually more commonly right-sided (>60% of cases) for unexplained reasons. Dandy's theory of "arterial elongation" (increased vessel tortuosity with age) may explain the unilateral juxtaposition of vessel(s) and nerve, but the incidence of TN should then be greater than 4-5/100,000. Additionally, whereas arterial pulsations provide a reasonable compression mechanism, venous compression of the large trigeminal nerve (21%-90% of cases) is not a parsimonious theory. The existence of asymptomatic vascular compression (13%-60% in cadaver studies) seems to further argue against an anatomical basis of MVD.

Conclusions CONCLUSIONS: The data suggest that the anatomical support for a vascular compressive etiology of TN is weak. How and why (and if) the arteries and veins commonly implicated become misaligned so that they exert pressure on the trigeminal nerve is not consistent with a brain sagging/vessel elongation aging process for many cases despite high reported success rates of some of the surgical studies.

Authors/Disclosures
Krystin L. Thomas PRESENTER	No disclosure on file
Fen-Lei F. Chang, MD, PhD (Parkview Neuroscience)	Dr. Chang has nothing to disclose.
Joel A. Vilensky, PhD	No disclosure on file
Mark S. Freedman, MD, FAAN (University of Ottawa)	Dr. Freedman has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Actelion(Janssen/J&J). Dr. Freedman has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Alexion. Dr. Freedman has received personal compensation in the range of $500-$4,999 for serving as a Consultant for BiogenIdec. Dr. Freedman has received personal compensation in the range of $500-$4,999 for serving as a Consultant for BMS/Celgene. Dr. Freedman has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for EMD Inc. Dr. Freedman has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Sanofi-Genzyme. Dr. Freedman has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Roche. Dr. Freedman has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Novartis. Dr. Freedman has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Actelion (Janssen/J&J). Dr. Freedman has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Alexion. Dr. Freedman has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Atara Biotherapeutics. Dr. Freedman has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Bayer Healthcare. Dr. Freedman has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for BiogenIdec. Dr. Freedman has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Clene Nanomedicine. Dr. Freedman has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for GRI Bio. Dr. Freedman has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Roche. Dr. Freedman has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Magenta Therapeutics. Dr. Freedman has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Merck Serono. Dr. Freedman has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis. Dr. Freedman has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sanofi Genzyme. Dr. Freedman has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Sanofi Genzyme. Dr. Freedman has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for EMD Serono. The institution of Dr. Freedman has received research support from Sanofi Genzyme.

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