Embolization of a peripheral cerebral aneurysm associated with intracranial major artery occlusion through a transdural anastomotic artery: Case report

Abstract

A peripheral cerebral aneurysm is known to develop at collateral vessels as a result of hemodynamic stress by the occlusion of the intracranial major arteries. We report a case of successful embolization of a ruptured aneurysm through a transdural anastomotic artery. The aneurysm formed at the developed collateral vessel from the meningeal branch of the occipital artery (OA) to the posterior pericallosal artery. A 59-year-old man presented with acute-onset headache, and computed tomography revealed subarachnoid hemorrhage and intracerebral hemorrhage at the splenium of the corpus callosum with intraventricular hemorrhage. Digital subtraction angiography demonstrated a ruptured aneurysm located at a transdural anastomotic artery from the right OA to the posterior pericallosal artery. The patient underwent endovascular treatment for the aneurysm through the transdural anastomotic artery with a coil and n-butyl-2-cyanoacrylate. Because it was impossible to navigate a microcatheter to the aneurysm through the right anterior cerebral artery because of the occlusion of its proximal portion, it was advanced through the transdural anastomosis from the right OA. The aneurysm was completely occluded without complications. Endovascular embolization is a useful treatment option for a peripheral cerebral aneurysm developed at a collateral vessel with intracranial major artery occlusion.

Introduction

In steno-occlusive diseases of major cerebral arteries such as moyamoya disease, hemodynamic stress causes aneurysms at peripheral arteries of the collateral circulation, which occasionally develop intracerebral or subarachnoid hemorrhage. These peripheral aneurysms are sometimes located at the fine collateral branches like moyamoya vessels in the deep region of the brain, in contrast to infectious aneurysms, which are usually induced in the small arteries of the brain surface. Therefore, direct surgery has a potential risk of the complications.¹

Here, we report a case of a ruptured peripheral aneurysm at a collateral artery that connected the meningeal branch of the occipital artery (OA) and the posterior pericallosal artery, which was successfully embolized through transdural anastomosis.

Case report

A 59-year-old man who had hypertension, chronic heart failure and chronic atrial fibrillation presented with a sudden headache and mild consciousness disturbance. On admission, he had no focal neurological deficits. Initial computed tomography (CT) demonstrated subarachnoid hemorrhage and intracerebral hemorrhage at the splenium of the corpus callosum with intraventricular hemorrhage (Figure 1).

Figure 1.

(a) and (b) Computed tomography images on admission showing subarachnoid hemorrhage and intracerebral hemorrhage at the splenium of the corpus callosum (arrow) with intraventricular hemorrhage.

Right internal carotid angiography (ICAG) revealed the occlusion of the left internal carotid artery (ICA) and the right anterior cerebral artery (ACA) at the A2 portion, and a collateral flow from the right ICA to the left ACA and the middle cerebral artery (MCA) through the anterior communicating artery (Figure 2(a)). Right vertebral angiography (VAG) showed a leptomeningeal anastomosis from the right posterior cerebral artery to the MCA territory (Figure 2(b)). Right external carotid angiography (ECAG) demonstrated a transdural anastomosis from the right ethmoidal artery and the middle meningeal artery (MMA) to the branches of the right ACA (Figure 2(c) and (d)), and from the right OA to the posterior pericallosal artery harboring an aneurysm (Figure 3(a) and (b)). Based on the finding of a fusion image of three-dimensional digital subtraction angiography (DSA) and CT, the aneurysm, located at the collateral artery from the right OA (Figure 3(c) and (d)), was considered as the bleeding source. Direct surgery was not feasible for the eradication of the aneurysm since the deep location of the aneurysms made it impossible to approach without damage to the transdural anastomoses. Therefore, endovascular treatment was adopted. Because access through the right ACA was impossible because of its occlusion at the A2 portion, it was advanced through the transdural anastomosis from the right OA.

Figure 2.

(a) Right internal carotid angiography (anteroposterior view) showing right A2 occlusion at the origin. There is a collateral flow through the anterior communicating artery to the left middle cerebral artery due to the left internal carotid artery occlusion. (b) Right vertebral angiography (anteroposterior view) showing leptomeningeal anastomosis. (c) and (d) Right external carotid angiography (anteroposterior and lateral view) showing the transdural anastomosis from the middle meningeal artery to the right anterior cerebral artery.

Figure 3.

(a) and (b) Right occipital angiography (anteroposterior and lateral view) showing the transdural anastomosis and a small aneurysm at the posterior pericallosal artery. (c) and (d) A fusion image of three-dimensional digital subtraction angiography of the right occipital artery and computed tomography showing a deeply located aneurysm.

Meticulous attention was paid to maintain cerebral circulation during general anesthesia. A 6 French sheath was introduced into the right femoral artery, and activated clotting time was prolonged adequately with systemic heparinization. A 6 French guiding catheter (Envoy; Codman & Shurtleff, Johnson & Johnson, Raynham, MA, USA) was advanced as distally as possible to the first segment of the right OA. Because the right OA was tortuous, a triple-coaxial system was required. A 4 French distal access catheter (Cerulean; Medikit, Tokyo, Japan) was also advanced as distally as possible to the third segment of the right OA (Figure 4(a)). Marathon (Medtronic, Minneapolis, MN, USA), a flow-guide catheter, finally reached just proximally to the aneurysm with the aid of a microguidewire (Chikai 008; Asahi Intecc, Nagoya, Japan). To avoid unexpected migration of n-butyl-2-cyanoacrylate (NBCA), a detachable coil, ED coil extrasoft® 1.5 mm × 2 cm (Kaneka Medix, Osaka, Japan), was placed in advance. Then, we injected 17% NBCA (Figure 4(b)), and achieved short-segment parent artery occlusion to avoid obstruction of the collateral pathways. DSA after the procedure confirmed complete disappearance of the aneurysm (Figure 5).

Figure 4.

(a) Right occipital angiography (lateral view). Arrow head indicates the position where the guiding catheter (6 French Envoy) was advanced and arrow indicates the position where the distal access catheter (4 French Cerulean) was advanced in the right occipital artery. (b) Super-selective angiography (left oblique view) just after the coil embolization showing a coil (arrow head) just proximal to the aneurysm.

Figure 5.

(a) and (b) Right occipital angiography (anteroposterior and lateral view) just after n-butyl-2-cyanoacrylate embolization. The aneurysm has completely disappeared.

There was no cerebral infarction on postoperative diffusion-weighted magnetic resonance images, and the patient was discharged without any neurological symptoms.

Discussion

In patients with intracranial major artery occlusion such as moyamoya disease, aneurysms sometimes develop at the collateral vessels because of hemodynamic stress. Actually, 4%∼15% of patients with moyamoya disease harbored aneurysms at the peripheral and proximal arteries in previous reports.^2–5 Although there were no moyamoya vessels in the present case, collateral vessels developed remarkably because of multiple intracranial major artery occlusion probably due to atherosclerosis. Therefore, we speculated that hemodynamic stress at the collateral vessels in this case would contribute to the aneurysm formation in the same way as moyamoya disease.

Regarding the treatment strategy of the present case, direct open surgery would be likely to damage the developed collateral vessels.⁶ In addition, the aneurysm was too small to identify in the deep location. Even if we could reach the aneurysm, preservation of the parent artery would be difficult. Therefore, we chose endovascular embolization.

For the treatment of peripheral aneurysms associated with moyamoya disease, endovascular embolization using coils or NBCA has been reported to achieve good results.^7–10 In the present case, the aneurysm was located at the anastomotic artery from the meningeal branch of the right OA to the posterior pericallosal artery. The only approach route was through the transdural anastomosis from OA because the right ACA was occluded at the origin of the A2 portion. Although endovascular aneurysmal embolization through superficial temporal artery-MCA bypasss,¹¹ OA-posterior inferior cerebellar artery bypass¹² and transdural anastomosis from MMA to the MCA developing as a collateral vessel of moyamoya disease⁸ has been reported, this is the first report of endovascular embolization of the aneurysm through the transdural anastomosis from the OA. The OA is usually highly tortuous, and it is quite difficult to advance a microcatheter to the distal part of the artery. But the recent development of endovascular devices such as the triple-coaxial system¹³ and flow-guide catheters,^14,15 as well as the advancement of endovascular treatment technique, has enabled the occlusion of deep-seated peripheral aneurysms. Because ED coil has the finest delivery wire system, it can be delivered through a Marathon catheter.¹⁵ Therefore, this coil is very useful for embolization using both coils and NBCA in distally located peripheral disease such as the aneurysm in this case. Although the handling of the microcatheter at the delicate collateral vessel needs sufficient attention to avoid vascular injury, endovascular embolization is a useful treatment for the deeply located cerebral aneurysm that developed at the collateral vessels with intracranial major artery occlusion.

Conclusion

We reported a case of successful embolization of a ruptured peripheral aneurysm formed at a collateral vessel through the meningeal branch of the OA. Endovascular embolization with recent advancements of devices and techniques may contribute to the improvement of outcome in patients with peripheral aneurysms.

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.