Distal anterior cerebral artery aneurysms: A brief review

Abstract

Distal anterior cerebral artery (DACA) aneurysms or pericallosal aneurysms are defined as aneurysms arising from any part of the A2 up to the A5 segments of the anterior cerebral arteries. They are relatively uncommon and have unique salient features that are pertinent to its accepted surgical management, hence requiring strong theoretical and conceptual knowledge. The objective of this study is to provide a comprehensive review and discussion on DACA aneurysms, from its nomenclature, anatomical characteristics and its impact on the pathophysiology, to the data on surgical management and outcome, and essential considerations required in the microneurosurgical approach, and to summarise the subject in a sequential and wholesome manner for a neurosurgeon at any stage of the career. Extensive review of available literature and surgical experiences published in indexed journals, was consolidated into concise text. DACA aneurysms represent about 6% of all intracranial aneurysms, and A3 aneurysms are the most common subtype. They have been identified at a mean age of 50 years, women more commonly affected, and found to be associated with other intracranial aneurysms. Patients present with subarachnoid haemorrhage in the distal interhemispheric fissure and pericallosal cisterns along with intracerebral and intraventricular haemorrhage in the vicinity of the frontal lobes, most commonly with Hunt and Hess Grade 2. The majority of such patients managed with surgical clipping had complete occlusion achieved in 67% and favourable outcome achieved in as many as 94%, versus a mortality rate of as high as 70% in conservatively managed cases, making surgical clipping through the interhemispheric approach is the preferred treatment modality. DACA is microsurgically interesting and challenging due to its peculiarities in anatomy. Microsurgical clipping of DACA aneurysms has been proven by literature, and tested by time, to be safe and have a favourable outcome, and hence must be taken up with clarity and vigour.