Thrombosed giant aneurysm of the distal anterior cerebral artery treated with aneurysm resection and proximal pericallosal artery-callosomarginal artery end-to-end anastomosis: Case report and review of the literature

Abstract

Background:Giant distal anterior cerebral artery (DACA) aneurysms are extremely rare, with only 32 cases reported in the literature. Most giant DACA aneurysms have features that make standard neck clipping difficult, and bypass surgery is sometimes required, although this surgery was performed in only three reported cases. This report presents the fourth case treated with bypass surgery.Case Description:A 69-year-old female presented with an unruptured thrombosed giant DACA aneurysm. She underwent wrapping operation 7 years before, but radiological imaging revealed enlargement of the aneurysm at the left pericallosal artery (PerA)–callosomarginal artery (CMA) junction. Before operation, three different strategies were considered for bypass surgery in case the neck could not be clipped. Aneurysm resection and left proximal PerA–CMA end-to-end anastomosis were successfully performed under intraoperative digital subtraction angiography (DSA) and motor-evoked potential (MEP) monitoring.Conclusion:Most DACA aneurysms are located at the PerA–CMA junction. In some cases, adequate retrograde flow to the distal PerA from the posterior or middle cerebral artery can be expected, making distal PerA reconstruction unnecessary. Moreover, when the distal PerA is cut, proximal PerA–CMA end-to-end anastomosis can be easily performed because of reduced tension in both vessels. We therefore conclude that this strategy should be utilized for treating such patients. We also presented here the effectiveness of intraoperative modalities, such as intraoperative DSA and MEP monitoring, for performing a safe operation.

A giant A4-A5 distal anterior cerebral artery aneurysm treated with microsurgical clip reconstruction

“…On the other hand, giant cerebral aneurysms are in themselves a rare occurrence, representing about 5-8% percent of all intracranial aneurysms (13). With a predilection for the posterior circulation, they tend to arise in large vessels, such as the basilar tip, and are usually partially or completely thrombosed (15,27). A possible explanation for this predilection is the increased flow rate at these locations, which increases the shear forces acting on the vessel wall, increasing the risk of damage and microdissection (32).…”

“…There are less than 40 cases of giant DACA aneurysms reported in the literature. The majority of those are fusiform in nature, and none are located at the A4-A5 segments (5,12,14,15,20,25). A possible explanation of this scarcity would be the decreased flow rate at the distal cerebral circulation, reducing the wall shear stress on the arterial walls and making damage, dissection, and formation of giant aneurysms less likely (8,18,32).…”

“…Moreover, coiling DACA aneurysms in general poses a challenge compared to other aneurysms, given the distal location of these lesions (12). As such, resection of these lesions with neck reconstruction or trapping with bypass may provide the best outcomes (15,22,31).…”

“…Fortunately, internal thrombectomy and decompression of the giant thrombosed part in our case was used reliably to reach the active part of the aneurysm and identify proximal and distal vessels. An alternative would be the use of neuronavigation to help guide the surgeon into the lesion (15).…”

A technique for sequential, progressive clipping for a giant thrombosed distal anterior cerebral artery aneurysm: Technical note

“…recently demonstrated that the proximal PcaA-CmaA end-to-end anastomosis with aneurysm resection was an effective treatment for a case with giant thrombosed DACA aneurysm. [ 12 ] We also considered aneurysmal resection with the left PcaA-right CmaA side-to-side anastomosis and the left A2-CmaA end-to-end anastomosis as another treatment option. However, the fact that the present clipping was feasible notwithstanding moderate calcification and thickening of the aneurysm suggests that our technique would be worth considering even in such cases.…”