Preoperative magnetic resonance imaging in Type 2 trigeminal neuralgia.

OBJECT: Trigeminal neuralgia (TN) is a neuropathic pain syndrome that is often associated with neurovascular compression of the trigeminal nerve and may be effectively treated with microvascular decompression (MVD). The authors used high-resolution MR imaging with 3D reconstruction in patients with constant facial pain (Type 2 TN) to determine the presence/absence of neurovascular compression and thus a potential MVD benefit. They retrospectively contacted patients to evaluate outcome.

METHODS: All patients who reported spontaneous onset of constant facial pain (Type 2 TN), which occurred at least 50% of the time, who had undergone high-resolution 3-T MR imaging with 3D reconstruction were retrospectively selected for this study. Clinical history, facial pain questionnaire data, physical examination findings, and results from 3-T 3D MR imaging reconstruction were recorded for all patients. Intraoperative findings and clinical pain outcome were recorded for all patients who underwent MVD.

RESULTS: Data obtained in 27 patients were assessed. On the basis of history and 3D MR imaging reconstruction findings, 13 patients were selected for MVD (Group A) and 14 underwent conservative treatment (Group B). Typical or suspected artery- or vein-induced neurovascular compression was predicted preoperatively in 100% of Group A patients and in 0% of Group B patients. At the time of MVD, definitive neurovascular compression was confirmed in 11 (84.6%) of 13 Group A patients. Following MVD, facial pain was completely relieved in 3 (23%), improved in 7 (53.8%), and no better in 3 (23%) of 13 Group A patients. A history of episodic (Type 1 TN) pain at any time was reported in 100 and 50% of Group A and Group B patients, respectively. A Type 1 TN pain component was reportedly improved/relieved in all Group A patients, but the Type 2 TN pain component was improved in only 7 (53.8%) of 13 patients. The mean postoperative follow-up duration was 13 months.

CONCLUSIONS: High-resolution 3D MR imaging reconstruction in patients with constant facial pain (Type 2 TN) can help determine the presence/absence of neurovascular compression. Surgical selection based on both clinical and radiological criteria has the potential to improve surgical outcome in patients with Type 2 TN who may potentially benefit from MVD. However, even in such selected patients, pain relief is likely to be incomplete.