Thalamic changes in patients with chronic facial pain.

PURPOSE

To investigate structural alterations in the thalamus in patients with primary trigeminal neuralgia and provide a detailed perspective on thalamic remodeling in response to chronic pain at the level of individual thalamic nuclei.  METHODS: We analyzed a sample of 62 patients with primary trigeminal neuralgia who underwent surgical treatment, along with 28 healthy participants. Magnetic resonance imaging (MRI) data were acquired using a 3T system equipped with a 16-channel receiver head coil. Segmentation of the thalamic nuclei was performed using FreeSurfer 7.2.0. We divided the group of patients with trigeminal neuralgia into two subgroups: those with right-sided pain and those with left-sided pain. Each subgroup was compared to a control group by means of one-way ANOVA. Associations between morphometric and clinical variables were assessed with Spearman correlation coefficient.

RESULTS

Our results revealed significant gray matter volume changes in thalamic nuclei among patients with trigeminal neuralgia. Notably, the intralaminar nuclei (centromedian/parafascicular) and nuclei associated with visual and auditory signal processing (lateral and medial geniculate bodies) exhibited significant alterations, contrasting with the ventral group nuclei involved in nociceptive processing. Additionally, we found no substantial volume increase in any of the studied nuclei following successful surgical intervention 6 months later. The volumes of thalamic nuclei were negatively correlated with pain intensity and disease duration.

CONCLUSION

The results of this study, although preliminary, hold promise for clinical applications as they reveal previously unknown structural alterations in the thalamus that occur in patients with chronic trigeminal neuralgia.