Neurovascular compression from a tortuous vertebrobasilar system. Technical note on surgical anatomy and cisternal microdissection

BACKGROUND: Microvascular decompression (MVD) for trigeminal neuralgia (TGN) typically entails mobilisation of the superior cerebellar artery or adjacent veins. Rarely, symptomatic compression arises from a tortuous vertebrobasilar system. These cases are challenging due to eloquence and distorted microsurgical anatomy in cerebellopontine angle (CPA) often needing more complex maneuvers like vessel transposition rather than conventional interposition technique. This technical note discusses MVD technical nuances for TGN from a tortuous vertebrobasilar system. METHOD: Standard retrosigmoid craniotomy was carried out to access the CPA. Radioanatomical correlations within the CPA were analyzed and an exposure extending along the tortuous vertebrobasilar system was planned for surgical control and visualization. Cerebellomedullary and cerebellopontine cisterns were dissected using combination of sharp and blunt techniques to release cranial nerves and resolve neurovascular conflict. CONCLUSION: We demonstrate the resolution of neurovascular conflict from tortuous vertebrobasilar system using interposition technique, without needing large vessel transposition. We illustrate radioanatomical correlations within the CPA and demonstrate dissection techniques in this challenging subtype of MVDs. Our technical observations are generalizable to microneurosurgical cases.