Microneurosurgical management of anterior communicating artery aneurysms

Abstract 

Background

Anterior communicating artery complex is the most frequent site of intracranial aneurysms in most reported series. Anterior communicating artery aneurysms are the most complex aneurysms of the anterior circulation due to the angioarchitecture and flow dynamics of the ACoA region, frequent anatomical variations, deep interhemispheric location, and danger of severing the perforators with ensuing neurologic deficits. The authors review the practical microsurgical anatomy, importance of preoperative imaging in surgical planning, and microneurosurgical steps in dissection and clipping of ACoAAs.

Methods

This review, and the whole series on intracranial aneurysms, are mainly based on the personal microneurosurgical experience of the senior author (JH) in 2 Finnish centers (Helsinki and Kuopio), which serve, without patient selection, the catchment area in Southern and Eastern Finland.

Results

These 2 centers have treated more than 10000 patients with aneurysm since 1951. In the Kuopio Cerebral Aneurysm Database of 3005 patients with 4253 aneurysms, 1145 patients (38%) had altogether 1179 ACA aneurysms; of them, 898 patients harbored 921 (78%) ACoAAs. In this series, 715 patients (80%) presented with ruptured ACoAAs with the median diameter of 7 mm. Giant ACoAAs were present in 15 (2%), whereas only 3 (0.3%) were classified as fusiform.

Conclusions

Anterior communicating artery aneurysms present frequently with SAH at small size. Furthermore, unruptured ACoAAs may have increased risk of rupture regardless of size, also as an associated aneurysm, and require treatment. The aim in microneurosurgical management of an ACoAA is total occlusion of the aneurysm sac with preservation of flow in all branching and perforating arteries. This demanding task necessitates perfect surgical strategy based on review of the 3D angioarchitecture and abnormalities of the patient's ACoA complex with its ACoAA and to orientate accordingly during the microsurgical dissection. The surgical trajectory should provide optimal visualization of the ACoA complex without massive brain retraction. Precise dissection in the 3D anatomy of the ACoA complex and perforators requires not only experience and skill but patience to work the dome and base under repeated protection of temporary clips and pilot clips. This is particularly important with the complex, large, and giant aneurysms.

Abbreviations: 3D, 3-dimensional, A1, Proximal segment of anterior cerebral artery, A2, postcommunicating segment of anterior cerebral artery, A1A, aneurysm of the A1 segment, A2A, aneurysm of the A2 segment, A3A, aneurysm of the A3 segment, ACA, Anterior cerebral artery, ACoA, Anterior communicating artery, ACoAA, Anterior communicating artery aneurysm, AdistA, aneurysm of the A4 and A5 segments, CMA, Callosomarginal artery, CSF, Cerebrospinal fluid, CT, computed tomography, CTA, CT angiography, DSA, Digital subtraction angiography, EC-IC, Extracranial-to-intracranial anastomosis, IA, intracranial aneurysm, ICA, Internal carotid artery, ICG, Indocyanine green, ICH, Intracerebral hematoma, ICP, intracranial pressure, ISUIA, International Study of Unruptured Intracranial Aneurysm Investigators, IVH, Intraventricular hematoma, LLA, Lateral lenticulostriate artery, LSO, lateral supraorbital, M1A, aneurysm of the M1 trunk, MbifA, middle cerebral artery bifurcation aneurysms, MCA, middle cerebral artery, MdistA, Distal MCA aneurysm, MLA, Medial lenticulostriate artery, MRI, Magnetic resonance imaging, RAH, Recurrent artery of Heubner, SAH, Subarachnoid hemorrhage

Keywords: Aneurysm, Anterior communicating artery, Anterior cerebral artery, Surgery, Microsurgical technique, Clipping, Subarachnoid hemorrhage