Multimodal MRI fusion and three-dimensional reconstruction for preoperative assessment of neurovascular compression in trigeminal neuralgia: A retrospective study.

BACKGROUND: Microvascular decompression is the primary surgical intervention for trigeminal neuralgia aimed at resolving neurovascular compression. Given the potential surgical risks, accurate preoperative assessment of neurovascular compression is critical. Although 3D visualization has been applied to preoperative assessment of neurovascular relationships, quantitative evaluation of the trigeminal nerve-vessel relationship and its association with intraoperative NVC findings remains limited.

MATERIALS AND METHODS: We retrospectively analyzed data from trigeminal neuralgia patients, hemifacial spasm controls and healthy controls. Preoperative 3D-FIESTA and 3D-TOF-MRA data were acquired and processed for 3D fusion reconstruction using 3D Slicer. After validating the model's reliability against intraoperative findings, trigeminal nerves were stratified into four subgroups. Anatomical morphological parameters and neurovascular relationships were quantitatively measured and compared among the subgroups. Immediate postoperative outcomes in trigeminal neuralgia patients were also evaluated.

RESULTS: A total of 92 trigeminal neuralgia patients, 99 hemifacial spasm controls and 30 healthy controls were enrolled. The trigeminal neuralgia cohort was significantly older than the control group (63.1 vs. 54.3 years, P < 0.05). The preoperative 3D reconstruction demonstrated high consistency with intraoperative findings (accuracy: 93%, Kappa: 0.89). ROC analysis identified an optimal neurovascular distance threshold of 1.23 mm for predicting intraoperative neurovascular compression (AUC = 0.957). Morphological analysis showed no significant intergroup difference in nerve diameter (P = 0.458), whereas cisternal length differed significantly among the five groups (P < 0.001). The TNS group showed the shortest mean neurovascular distance (1.1 mm, P < 0.001) and the highest prevalence of neurovascular compression (NVC) (79.3%, P < 0.001). These findings remained consistent after inclusion of healthy controls. Immediate postoperative outcomes were not significantly associated with intraoperative NVC status or the 1.23-mm neurovascular distance.

CONCLUSION: This study confirmed the high diagnostic accuracy of preoperative 3D MRI fusion. Crucially, a neurovascular distance threshold of 1.23 mm was identified as an exploratory imaging marker for definite intraoperative compression. However, this threshold should not be regarded as an independent criterion for treatment selection.