Occipital Interhemispheric Transtentorial Approach for Microsurgical Treatment of Posterior Midbrain Arteriovenous Malformation: 2-Dimensional Operative Video.

Arteriovenous malformations (AVMs) of the brain stem are very rare lesions accounting for 2% to 6% of the cerebral AVMs.1,2 They carry higher risk of hemorrhage3,4 and are associated with poor prognosis.5-7 This is a 27-year-old man who presented with intraventricular hemorrhage, hydrocephalus, and poor neurological status secondary to ruptured AVM. Deep branches from right triplicate superior cerebellar artery, left duplicate superior cerebellar artery, and right posterior cerebral artery were feeding the AVM. The drainage was directly to the vein of Galen. MRI brain showed the location of the AVM in the posterior midbrain area. The AVM was mostly exophytic to brain stem parenchyma which made it favorable for surgical resection.8 After cerebrospinal fluid diversion (initially with external ventricular drain that was then converted to ventriculoperitoneal shunt), the patient showed some neurological improvement over the next weeks. Thus, the decision was made to treat the AVM. The patient underwent preoperative embolization followed by an occipital interhemispheric transtentorial approach. This illustrative video outlines the steps and technical nuances of the right occipital interhemispheric transtentorial approach for microsurgical resection of this Spetzler-Martin grade 3 (S1, E1, V1)/supplementary Spetzler-Martin grade 2 (A2, B0, C0) AVM. Postoperative cerebral angiogram demonstrated no AVM residual. The patient was discharged to a rehabilitation institute and at 3 months of follow-up, he was alert and orientated to time, person, and place without focal deficits. The patient consented to the procedure and to the publication of his image. Institutional Review Board approval was deemed unnecessary.