Successful flow reduction surgery for a ruptured true posterior communicating artery aneurysm caused by the common carotid artery ligation for epistaxis

Cerebral Aneurysms with Internal Carotid Artery Agenesis: A Unique Case Similar to Moyamoya Disease and Literature Review

Internal carotid artery (ICA) agenesis/aplasia is occasionally accompanied with cerebral aneurysms caused by hemodynamic stress. If the aneurysms are located around the circle of Willis, they are managed with clipping or coil embolization. Herein, we report a case of ICA agenesis with perforating artery aneurysms treated successfully with revascularization. Moreover, a literature review of ICA agenesis with cerebral aneurysms was performed to compare with the current case. We conducted a literature review using data from PubMed. A secondary search was also performed by reviewing the references of each article previously searched. In our case, the aneurysms shrank and disappeared after direct and indirect bypass surgeries, and indirect bypass developed as in moyamoya disease (MMD). The epidemiological and clinical features of aneurysms accompanied with ICA agenesis were identified via a literature review. Aneurysms with ICA agenesis categorized as type F based on the Lie classification system, or referred to as rete mirabile, are occasionally located in an untreatable site; hence, they cannot be treated with clipping or coil embolization. Moreover, results showed that previous studies did not use revascularization for the treatment of aneurysm. In conclusion, if an aneurysm with ICA agenesis is difficult to approach directly or via an endovascular procedure, revascularization can be a treatment option.

Blind-Alley Formation and Occipital Artery-Posterior Inferior Cerebellar Artery Bypass for the Treatment of Unclippable Vertebral Artery Aneurysms with Posterior Inferior Cerebellar Artery Involvement

BACKGROUND AND IMPORTANCE

Unclippable vertebral artery aneurysms (UVAs) are difficult to treat with direct clipping, especially in cases involving the origin of the posterior inferior cerebellar artery (PICA). Bypass with trapping is the common procedure used for these conditions. The authors used the blind-alley formation technique, which is a simpler method than trapping and can avoid some complications.

OBJECTIVES

To report 7 cases of UVA with PICA involvement treated with blind-alley formation and occipital artery (OA)-PICA bypass as well as their surgical outcomes and complications and to describe the operative techniques.

RESULTS

Seven patients with UVA and PICA involvement underwent OA-PICA bypass and blind-alley formation (occlusions of the PICA origin and vertebral artery proximal to the aneurysm). Vertebral artery dissecting aneurysms and fusiform atherosclerotic vertebral artery aneurysms were detected in 6 patients and 1 patient, respectively. All patients presented with subarachnoid hemorrhage, and 71.4% of them were classified into the poor-grade group. Good bypass patency and complete aneurysm obliteration were achieved in all cases. Six aneurysms (85.7%) were completely obliterated according to computed tomography angiography performed immediately postoperatively. Another aneurysm was 50% and 100% thrombosed immediately and at 7 days after the operation, respectively. Surgical complications were found in 1 patient (14.3%) who had postoperative diparesis with dysphagia. Three patients (42.9%) achieved a Glasgow Outcome Score of 4 or 5 one month after the operation.

CONCLUSIONS

Blind-alley formation and OA-PICA bypass are simple, safe, and effective for the treatment of patients with UVA with PICA involvement.

Ruptured Basilar Tip Aneurysm in a Patient with Bilateral Internal Carotid Artery Occlusion Successfully Treated with Bilateral Superficial Temporal Artery-Middle Cerebral Artery Anastomoses: Case Report

BACKGROUND

Some ruptured intracranial aneurysms concomitant with major artery occlusion may not be amenable for standard clipping or coiling due to the specific hemodynamic conditions. The long-term effect of flow reduction therapy for such aneurysms is largely unknown.

CASE PRESENTATION

A 45-year-old woman presented with subarachnoid hemorrhage due to a ruptured basilar tip aneurysm. Angiography revealed that the bilateral internal carotid arteries were hypoplastic and that the anterior circulation was fed by the collateral flow through the bilateral posterior communicating arteries and the posterior choroidal arteries. Endovascular treatment failed because it was extremely difficult to secure the catheter at the neck of the aneurysm and insert the coil safely because it was a small aneurysm with a wide neck. In addition, direct clipping was risky due to the location and projection of the aneurysm. We therefore adopted the 2-stage bilateral superficial temporal artery-middle cerebral artery bypass to alleviate the vascular demand on the anterior circulation, with the aim of reducing the hemodynamic stress to the basilar bifurcation. The patient had no rebleeding for 4 years after surgery, with gradual shrinkage of the aneurysm.

CONCLUSION

All the possible treatment options should be carefully assessed because the long-term effect of the flow alternation method to prevent rebleeding has not been proved. However, our case suggests that the strategy of reducing the hemodynamic stress at the parent artery may be effective even in selected cases of ruptured aneurysms for which standard clipping or coiling is not feasible.