Microsurgery and endovascular therapy serve instrumental roles in multimodal management of giant cerebral aneurysms: a systematic review.

[INTRODUCTION] Giant intracranial aneurysms are rare vascular lesions consisting of cerebral aneurysms measuring ≥25 mm in diameter. Their formation is the result of multiple factors including their association with a unique genomic landscape, pathophysiologic processes associated with the pathognomonic, histopathological changes observed within the arterial wall, the physical effects of the cerebral vasculature's unique fluid dynamics, and slow growth rates. Because giant intracranial aneurysms are considered among the most complex to manage, we herein perform a systematic review of the extant evidentiary base found within the neurosurgical literature with the goal of profiling multimodality management strategies for these lesions. Additionally, we will highlight the importance of integrating neuroendovascular surgery into microsurgical treatment regimens for giant cerebral aneurysms.

[EVIDENCE ACQUISITION] To this end, we performed a systematic review of the literature through the PubMed, Scopus and Web of Science databases according to PRISMA guidelines. By using predefined search terms, we intended to identify prior reports involving multimodality management of giant intracranial aneurysms. Specifically, we sought to highlight the integral role of both neuroendovascular and microsurgical interventions in treatment of these rare vascular lesions.

[EVIDENCE SYNTHESIS] Ten studies reporting outcomes for 91 patients met criteria for inclusion in the present meta-analysis. Within this cohort of patients, mean age varied from 39.0 to 60.1 years. Among the giant aneurysms in the present review, many were found extending off of the supraclinoid ICA, which is one of the most common sites for giant intracranial aneurysms to form. In 1988, Batjer described the earliest combined intervention included in the present study. Since then, two common approach type themes involved in multimodal management have evolved: combined strategies often consist of 1) an endovascular approach to vessel occlusion, such as embolization, and 2) a microsurgical method capable of eliminating the aneurysm following control of blood flow. In other words, achieving obliteration via clipping, bypass surgery, clip reconstruction, wrapping, and Hunterian ligation (among others). Review of the literature indicated an overall mortality rate associated with multimodal management of 5.4%. Radiographic obliteration rates were reported in three of ten studies. One of the studies reported an 82.9% rate of successful obliteration. Rates of good outcomes (mRS 0-2, GOS 4-5) ranged from 60% up to a maximum of 87.5%.

[CONCLUSIONS] Combined, multimodality endovascular and microsurgical treatments appear to be most successful for the treatment of giant aneurysms because of their adaptability, the flexibility they confer, and the synergistic effect of combining the strengths of multiple modalities.