Three-dimensional visualization of neurovascular compression: presurgical use of virtual endoscopy created from magnetic resonance imaging

To assess the usefulness of presurgical simulation of microvascular decompression (MVD) by virtual endoscopy (VE), a new tool to analyze three-dimensionally reconstructed magnetic resonance data sets in patients with trigeminal neuralgia or hemifacial spasm (HFS). In 17 patients (10 with trigeminal neuralgia and seven with HFS) determined to be candidates for MVD, we performed presurgical simulation of MVD using VE. We used constructive interference in steady-state imaging and magnetic resonance angiography to obtain the original images. VE findings were compared with surgical findings. The three-dimensional relations between visible structures seen on VE were consistent with intraoperative findings in all patients. In total, 20 (91%) of 22 neurovascular compression sites in all 17 patients were correctly delineated on VE, with the exception of two small branches identified as offending vessel in two patients with HFS. Perforators that were not apparent on VE limited our ability to accomplish transpositioning of the offending vessels as simulated. The positions of structures that can affect individual surgical approaches, such as the petrosal vein, cerebellar flocculus, and vertebral artery, were also adequately predicted on VE. All patients had excellent surgical outcomes. Presurgical VE in patients with trigeminal neuralgia or HFS is a novel technique that provides excellent visualization of the three-dimensional relations between neurovascular structures and allows simulation of MVD.