Imaging-Based Evaluation of Neurovascular Compression in Classical Trigeminal Neuralgia

AIM: This study evaluated magnetic resonance imaging (MRI) features of neurovascular compression and posterior fossa morphometry in classical trigeminal neuralgia, emphasizing the symptomatic side and distinguishing simple contact from clinically relevant compression.
MATRERIAL and METHOD: This retrospective study included 31 patients with classical trigeminal neuralgia. The symptomatic ipsilateral side and asymptomatic contralateral side were compared as paired observations. Sixty-two trigeminal nerve sides were assessed for neurovascular compression presence and grade, contact location, offending vessel, contact direction, nerve diameter, atrophy, deviation, cerebrospinal fluid distance, cerebellopontine angle cistern dimensions and area, and flocculus–trigeminal nerve distance. Subgroup analyses were performed according to ipsilateral compression severity.
RESULTS: Neurovascular compression was more frequent ipsilaterally than contralaterally (80.6% vs 38.7%, p<0.001), as was Grade ≥2 compression (32.3% vs 6.5%, p<0.001). Root entry zone contact was more common on the symptomatic side (25.8% vs 3.2%, p=0.030). The superior cerebellar artery was the predominant contacting vessel, particularly ipsilaterally (64.5% vs 29.0%, p=0.004). Ipsilateral trigeminal nerve diameter was smaller (2.1±0.4 vs 2.3±0.3 mm, p=0.025). Increasing ipsilateral compression severity was associated with decreasing nerve diameter (2.3, 2.3, and 1.7 mm for no compression, Grade 1, and Grade ≥2, respectively; p=0.002), while atrophy and deviation occurred predominantly with Grade ≥2 compression. Posterior fossa and flocculus-related measurements showed no significant differences.
CONCLUSION: Symptomatic sides demonstrated more frequent, severe, and morphologically consequential neurovascular compression. Compression severity, rather than simple contact alone, may better indicate clinically relevant neurovascular conflict during routine MRI assessment and clinical decision-making for patients.