Pain Relief-Related Structural Brain Alterations in Trigeminal Neuralgia Induced by Noninvasive Stereotactic Radiosurgery: A Pilot Study

Purpose: Trigeminal neuralgia (TN) is a chronic pain disorder defined fi ned by unilateral shock-like pain in at least one division of the trigeminal nerve. Although several studies have investigated structural brain plasticity in patients with TN, treatment- induced alterations remain largely uninvestigated. Methods and Materials: Combining T1-weighted magnetic resonance imaging with voxel-based morphometry and multiple- regression analyses, we assessed gray matter maps of patients with TN to investigate changes in gray matter volume (GMV) before and 6 months after stereotactic radiosurgery (SRS). Results: Comparison of pre- and post-SRS GMV of 25 patients with TN (16 women; mean age 67 years) did not yield any significant fi cant clusters, suggesting that the effect of SRS intervention itself on gray matter structure may be negligible. Regarding SRS-induced pain relief, we found a significant fi cant GMV increase in the left superior frontal gyrus associated with greater degree of pain relief (P = .024) and a trend toward an increase in GMV in the left dorsolateral prefrontal cortex (P = .097). Conclusions: In this pilot study, we observed significant fi cant increases in GMV in the left superior frontal gyrus with SRS-induced improvements in pain and a trend toward an increase in GMV in the dorsolateral prefrontal cortex. Future studies are indicated to validate these fi ndings and determine whether SRS-induced decrease in distracting pain events and subsequent increases in GMV result in improved functionality, decreased dependence on " top-down" " control, and improved cognitive/ executive balance with amelioration of pain events. (c) 2024 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/)