Microvascular decompression on patients with trigeminal neuralgia caused by ectatic vertebrobasilar artery complex: technique notes

Abstract

Due to its anatomical features, the vertebrobasilar artery complex (VBA) seldom contributes to the neurovascular conflict in patient with trigeminal neuralgia (TN). However, once it offends the trigeminal root, this large artery is really difficult to manipulate during microvascular decompression (MVD) surgery. Therefore, the surgical strategy for such cases needs to be detailed in order to obtain a satisfactory outcome. From 2009 through 2011, 475 consecutive TN patients underwent MVDs in our department. Among them, ten were found in which an ipsilateral deviating ectatic vertebrobasilar artery complex (VBA) offended the trigeminal nerve. Those cases were focused on in this study and each operation was analyzed retrospectively. During the operation, the vertebral artery was regarded as the direct culprit in six (60 %) patients, while the basilar artery in four (40 %). As companions, some smaller vessels were also observed to be close to the nerve, including the superior cerebellar artery (SCA) in five, veins in two and anterior inferior cerebellar artery (AICA) in two. The neurovascular conflict was discovered in the cisternal segment of the trigeminal root in eight, while in the root entry zone (REZ) in two. In six out of the ten cases, the affected nerves were demonstrated to be squeezed towards the tentorium by the ectatic VBA. Postoperatively, the symptom of pain totally disappeared immediately in eight (80 %) patients, while it was relieved apparently in two (20 %). During the follow-up period of 3-30 months, no recurrence or complication was found, except for one patient who had numbness of the face. With a proper strategy, MVD is probably the most effective therapy for the TN cases caused by ectatic vertebrobasilar artery complex. The substance of the surgery is to withdraw the proximal vertebral artery caudally via a lateroinferior cerebellar approach.