Introduction: Trigeminal neuralgia (TN) is a neuropathic disorder characterized by high intensity electric shock-like attacks of unilateral pain. In medically refractory patients, neurosurgical interventions such as stereotactic radiosurgery (SRS) of the trigeminal nerve at or near the root entry zone (REZ) can relieve pain and effectively impact REZ microstructure. However, the mechanism of these interventions’ influence on the trigeminal nerve and subsequent analgesic effect are not well understood.
Methods: Patients included in the study were any patients who underwent SRS for TN at Ronald Reagan UCLA Medical Center and who had diffusion tensor magnetic resonance imaging performed after treatment. Fractional anisotropy was extracted bilaterally from each trigeminal REZ. Pain reduction was measured in terms of Barrow Neurological Institute scores at 6-month follow-up. Student’s t-test was employed with a threshold of significance set at p < 0.05.
Results: Twelve patients (3 males and 9 females) were included in this study. Seven of the twelve patients had good outcomes (BNI score 3a or less) following therapy. Patients with good responses to treatment had significantly larger fractional anisotropy values over the distribution of the trigeminal nerve of the affected side (mean ± standard deviation: 0.29 ± 0.075) relative to patients with poor outcomes post-SRS (0.16 ± 0.092, p = 0.028).
Conclusions: These results support a role of DTI in detecting subtleties of microstructural changes of the trigeminal nerve and suggest its potential use as an adjunct in assessing patient outcomes after treatment. The use of such metrics could permit a better means of prognosis and assessment of treatment response, bringing us closer to personalizing therapy through measures that are both objective and noninvasive.
Patient Care: This research provides supporting evidence for the potential use of diffusion tensor imaging in assessing patient outcomes
Learning Objectives: By the conclusion of this session, participants should be able to describe the potential applications of diffusion tensor imaging in assessing outcomes of patients with trigeminal neuralgia after stereotactic radiosurgery.