Malignant glioma is the most common primary brain tumor and carries a grim prognosis, with a median survival of just over 14 months. Given the poor outcomes with standard-of-care treatments, novel treatment strategies are needed. The concept of virotherapy for the treatment of malignant tumors dates back more than a century and can be divided into replication-competent oncolytic viruses and replication-deficient viral vectors. Oncolytic viruses are designed to selectively target, infect, and replicate in tumor cells, while sparing surrounding normal brain. A host of oncolytic viruses has been evaluated in early phase human trials with promising safety results, but none has progressed to phase III trials. Despite the 25 years that has passed since the initial publication of genetically engineered oncolytic viruses for the treatment of glioma, much remains to be learned about the use of this therapy, including its mechanism of action, optimal treatment paradigm, appropriate targets, and integration with adjuvant agents. Oncolytic viral therapy for glioma remains promising and will undoubtedly impact the future of patient care.

OBJECTIVE Flow diversion for posterior circulation aneurysms performed using the Pipeline embolization device (PED) constitutes an increasingly common off-label use for otherwise untreatable aneurysms. The safety and efficacy of this treatment modality has not been assessed in a multicenter study. METHODS A retrospective review of prospectively maintained databases at 8 academic institutions was performed for the years 2009 to 2016 to identify patients with posterior circulation aneurysms treated with PED placement. RESULTS A total of 129 consecutive patients underwent 129 procedures to treat 131 aneurysms; 29 dissecting, 53 fusiform, and 49 saccular lesions were included. At a median follow-up of 11 months, complete and near-complete occlusion was recorded in 78.1%. Dissecting aneurysms had the highest occlusion rate and fusiform the lowest. Major complications were most frequent in fusiform aneurysms, whereas minor complications occurred most commonly in saccular aneurysms. In patients with saccular aneurysms, clopidogrel responders had a lower complication rate than did clopidogrel nonresponders. The majority of dissecting aneurysms were treated in the immediate or acute phase following subarachnoid hemorrhage, a circumstance that contributed to the highest mortality rate in those aneurysms. CONCLUSIONS In the largest series to date, fusiform aneurysms were found to have the lowest occlusion rate and the highest frequency of major complications. Dissecting aneurysms, frequently treated in the setting of subarachnoid hemorrhage, occluded most often and had a low complication rate. Saccular aneurysms were associated with predominantly minor complications, particularly in clopidogrel nonresponders.

Clopidogrel nonresponders experienced a significantly higher rate of thromboembolic complications when compared with clopidogrel responders. However, this risk seems to be mitigated in nonresponders who were switched to ticagrelor or received a clopidogrel boost within 24 hours pre-procedure.

Vein of Galen aneurysmal malformations are a rare and diverse group of entities with a complex anatomy, pathophysiology, and serious clinical sequelae. Due to their complexity, there is no uniform treatment paradigm. Furthermore, treatment itself entails the risk of serious complication. Offering the best treatment option is dependent on an understanding of the aberrant anatomy and pathophysiology of these entities, and tailored therapy is recommended. Herein, the authors review the current concepts related to vein of Galen aneurysmal malformations and suggest a new classification system excluding mesodiencephalic plexiform intrinsic arteriovenous malformations from this group of malformations.