Pain Relief Reverses Hippocampal Abnormalities in Trigeminal Neuralgia

Abstract

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Leveraging high-resolution 7-tesla MRI to derive quantitative metrics for the trigeminal nerve and subnuclei of limbic structures in trigeminal neuralgia

“…Although no effects were shown in subnucleus volumes versus disease duration, this correlation should be explored further in future work with a larger cohort to validate previous findings which suggest that duration of symptoms may be linked to structural alterations in TN 26 . Future work evaluating the intensity of TN attacks, presence of sensory deficit, and allodynia can further elucidate the relationship between pain and structural changes in TN.…”

“…Advanced imaging studies are increasingly being applied to study TN. Studies have shown structural changes in trigeminal nerves [17][18][19][20] and limbic structures [21,[23][24][25][26] in the presence of TN pathology. In this study, ultra-high field MRI provided excellent resolution of the trigeminal nerves as well as granular subregions of the hippocampus, amygdala, and thalamus.…”

“…Vaculik et al found volumetric reductions in ipsilateral hippocampal subfields in two cornu ammonis (CA) regions, CA1 and CA4, as well as in the dentate gyrus (DG) in TN patients [25]. Noorani et al found that pain relief can reverse hippocampal abnormalities in trigeminal neuralgia and suggests that hippocampal volume reduction in TN is pain-driven [26]. These findings provide strong premise and motivation for further investigation of trigeminal nerve anatomy and subregions of limbic structures with hypothesized involvement in TN pain.…”

“…The hippocampus, amygdala, and thalamus are of particular interest when it comes to exploring TN pathophysiology. The hippocampus is a stress-sensitive structure which can undergo changes in the presence of chronic pain [21,25,26]. The amygdala, which is the hub of the emotion-related network and involved in stress regulation, may be associated with pain in TN as well [21,27].…”

Recent update on trigeminal neuralgia

“…A study found that volume recovery or normalization reveals sex-specific hippocampus plasticity in TN, with females experiencing a higher volumetric increase than males. They hypothesized that hippocampus shrinkage in TN is caused by pain, and that proper treatment can correct these anomalies [62].…”