Cerebellar lobular morphometry in trigeminal neuralgia: cross-sectional and exploratory postoperative analyses

Cerebellar morphometric findings in trigeminal neuralgia (TN) are inconsistent, and lobular volume and cortical thickness are poorly characterized. We compared cerebellar lobular morphometry between patients with TN and healthy controls (HCs) and explored postoperative changes.

We included 86 patients with TN and 40 HCs; 49 patients had paired preoperative and postoperative magnetic resonance imaging (MRI). DeepCERES was used to quantify bilateral volume and MRI-derived mean cortical thickness in 12 cerebellar regions. Cross-sectional regression models adjusted for age (linear and quadratic terms) and sex; volume models additionally adjusted for intracranial volume (ICV). Longitudinal changes were assessed using paired t tests. False discovery rate (FDR) correction was applied separately to the 12 tests for each measure.

No regional or global cerebellar volume differences were significant after FDR correction in the cross-sectional analysis. Patients with TN had higher MRI-derived mean cortical thickness in Lobules IV and VI than HCs. Adjusted differences were 0.104 mm (95% confidence interval [CI], 0.040-0.168; q = 0.020) for Lobule IV and 0.071 mm (95% CI, 0.021-0.121; q = 0.036) for Lobule VI. The Lobule IV difference was significant across the age models examined, whereas the Lobule VI finding was sensitive to how age was modeled. Among the 49 patients with paired MRI, volume increased postoperatively in Lobules IV-VI, VIIb, VIIIa, and VIIIb, and thickness increased in Lobules IV-VI (all q < 0.05). Across these regions, the mean of individual percentage changes ranged from 0.86 to 1.69% for volume and from 1.38 to 3.00% for thickness. Three of the six volume increases and all three thickness increases remained significant after FDR correction in sensitivity models accounting for changes in ICV and automated quality scores.

Patients with TN had higher MRI-derived cortical thickness in Lobules IV and VI than HCs, with the most consistent evidence in Lobule IV. No significant between-group differences in cerebellar volume were detected. Postoperative increases in volume and thickness across several lobules are exploratory findings whose biological significance requires further investigation.