Elsevier

Surgical Neurology

Volume 55, Issue 3, March 2001, Pages 148-154
Surgical Neurology

Vascular
Characteristics of aneurysms arising from the horizontal portion of the anterior cerebral artery

https://doi.org/10.1016/S0090-3019(01)00396-2Get rights and content

Abstract

BACKGROUND

Aneurysms arising from the proximal portion of the anterior cerebral artery (A1: horizontal portion) are quite rare and are considered to be unique, because they are usually connected with other vascular anomalies and are sometimes part of a multiple aneurysm occurrence. A1 aneurysm cases experienced over the past seven and a half years are summarized in this paper.

METHODS

A total of 413 patients were surgically treated including 142 patients with subarachnoid hemorrhage (SAH); the remaining 271 patients had unruptured aneurysms. Among them, nine cases were categorized as constituent A1 aneurysms, three with SAH and six with unruptured aneurysms.

RESULTS

The shape of the aneurysm was saccular in all nine cases. Three of the nine cases had associated vascular malformations. The average aneurysm diameter in the three cases with SAH was 4.0 mm, which is smaller than other common aneurysms presenting with SAH. Eight aneurysms developed at the takeoff point of perforating arteries—the medial lenticulostriate artery in five cases and the recurrent artery of Heubner in three cases. In the remaining case, the aneurysm originated from the proximal end of the associated A1 fenestration. All nine patients had an excellent outcome after surgery.

CONCLUSION

A1 aneurysms require surgical elimination even if they are small. We emphasize the importance of preserving the blood flow of these perforating arteries by avoiding compression with either the clip blade or the clip body itself.

Section snippets

Materials and methods

Our strategy for treatment of cerebral aneurysms is as follows: aneurysms causing SAH will be eliminated by a clipping procedure as soon as possible. Furthermore, patients with various complaints will undergo a careful examination of the brain, primarily by magnetic resonance imaging (MRI). Thus, the majority of our patients will routinely undergo ordinary axial MRI and MRA. The individuals who are diagnosed with an asymptomatic aneurysm of more than 3 mm in diameter or those who simply request

Summary of cases manifested with SAH

Three cases were SAH-related and are summarized in Table 1 (top). The ages of these patients ranged from 43 to 71 years (mean, 57 years old); there were two women and one man. The shape of the aneurysms was saccular in all three cases and their maximum diameter ranged from 3.4 to 5.0 mm (mean, 4.0 mm). Angiography and surgery revealed that the aneurysms were located at the distal corner of the origin of the medial lenticulostriate artery (LSA) in two cases and the recurrent artery of Heubner

Comparison between SAH group and the asymptomatic group

The characteristics of the aneurysms are classified and summarized according to the cases with and without SAH (Table 1). The shape of the aneurysm was saccular in all cases. The diameter of the aneurysm in cases with SAH tended to be larger compared to those without SAH; however, there was no statistically significant difference. There seemed to be no difference between these groups in regard to the location of the aneurysm, relationship to the perforating artery, or relationship to A1

Discussion

A1 aneurysms are relatively rare, accounting for only about 1% of all cerebral aneurysms 1, 3, 12, 15. We experienced three cases of SAH because of ruptured A1 aneurysms; the maximum diameter of these aneurysms was less than 5.0 mm. In a study of a large number of aneurysm cases, the average diameter of the ruptured aneurysms was reported to be 8.2 mm [5]. The median diameter of our three SAH cases was 4.0 mm—significantly smaller than the majority of those reported in the literature.

Conclusion

The average size of A1 aneurysm in our three cases with SAH was 4.0 mm in maximum diameter, smaller than aneurysms occurring in other common locations that present with SAH. This suggests that A1 aneurysms require surgical elimination even if they are small and unruptured. Most of the A1 aneurysms in our series developed at the distal corner of the origin of a perforating artery.

Three of the nine cases were associated with other vascular malformations, suggesting there may be some congenital

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  • Radiological and clinical outcomes of endovascular coiling of proximal A1 aneurysms

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    In addition, the recurrence and retreatment rates of endovascular coiling were relatively high, with the number of rupture recurrences being significant. In general, proximal A1 aneurysms involve one of the most difficult locations for endovascular coiling because navigating microwires or microcatheters into the aneurysm is not feasible and the microcatheter will be unstable for endovascular coiling [8,10,14–19]. Because microwires should be navigated firstly into the anterior cerebral artery and subsequently should be superselected into the posterior or posterosuperior directed proximal A1 aneurysms, these angiographic features of proximal A1 aneurysms can be unnatural and challenging for microwire navigation or microcatheter superselection.

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