ObjectiveTo clarify the safety and efficacy of pre-operative embolization using Onyx liquid embolic agent (Onyx; ev3) compared with N-butyl cyanoacrylate (NBCA; Cordis Neurovascular, Inc.) or coils in cerebral arteriovenous malformation (AVM) surgery.MethodsThis was a retrospective review of a prospectively collected clinical database of brain AVMs treated at our institute from January 2005 to March 2021. A total of 38 consecutive patients who underwent AVM resection after pre-operative embolization were included. Based on pre-operative embolization materials, the patients were divided into the pre-Onyx group (n = 16), in which NBCA or coils were used for embolization, and the Onyx group (n = 22). Patient characteristics and treatment results were compared between the two groups.ResultsPatient characteristics were comparable between the two groups in terms of age, sex, and rupture status. While the Spetzler–Martin grade was also similar between the two groups, the location of the AVM nidus in the eloquent area was slightly higher in patients in the Onyx group (72.7%) than in patients in the pre-Onyx group (43.8%) (P = 0.09). The embolization rate was higher in the pre-Onyx group (mean: 63.0%; range: 12.7–100%) than in the Onyx group (mean: 50.0%; range: 15.8–100%), but the difference was not statistically significant (P = 0.06). The time needed for surgical removal was shorter in the Onyx group (mean: 354.8 min; range: 144–884 min) than in the pre-Onyx group (mean: 457.9 min; range: 240–1,294 min); however, this difference was not statistically significant (P = 0.13). The amount of intraoperative bleeding was significantly lower in the Onyx group (mean: 129.8 ml; range: 20–540 mL) than in the pre-Onyx group (mean: 448.8 mL; range: 120–1,550 ml) (P = 0.0008). The surgical complication rates were comparable between the two groups (pre-Onyx group, 18.8%; Onyx group, 4.5%; P = 0.29).ConclusionsPre-operative embolization with Onyx can significantly reduce the amount of intraoperative bleeding in AVM resection and may contribute to safe AVM surgery.

Ischemic stroke associated with intracranial aneurysm is rare but potentially happens because of emboli originating from aneurysm sac or aneurysmal thrombosis extension to the parent artery. We describe two patients who present subarachnoid hemorrhage (SAH) soon after ischemic stroke. Case 1. A 51-year-old woman with a history of multiple endovascular therapy for ruptured basilar top aneurysm presented with double vision. Magnetic resonance imaging (MRI) revealed infarcts in the right thalamus and left occipital cortex. Four days after ischemic stroke, she suffered from sudden onset headache, computed tomography (CT) showed diffuse SAH with intraventricular hemorrhage. Case 2. A 62-year-old man presented with right facial palsy and sensory disorder. MRI revealed an infarct in the left pons. Four days after ischemic stroke, he became comatose and CT showed diffuse SAH. Both cases develop ischemic stroke adjacent to the aneurysms and subsequently cause devasting aneurysm rupture, suggesting ischemic stroke as a warning sign of aneurysm rupture. In such cases, early treatment of the aneurysm should be considered.

Background and Objectives: Non-cystic manifestation of autosomal dominant polycystic kidney disease (ADPKD) is an important risk factor for cerebral aneurysms. In this report, we describe a rare spontaneous internal carotid artery (ICA) dissection in a patient with ADPKD. Observations: A 38-year-old woman with a history of ADPKD and acute myocardial infarction due to coronary artery dissection experienced severe spontaneous pain on the left side of her neck. Magnetic resonance imaging (MRI) revealed a severe left ICA stenosis localized at its origin. Carotid plaque MRI showed that the stenotic lesion was due to a subacute intramural hematoma. Close follow-up by an imaging study was performed under the diagnosis of spontaneous extracranial ICA dissection, and spontaneous regression of the intramural hematoma was observed uneventfully. Conclusions: When patients with a history of ADPKD present with severe neck pain, it is crucial to consider the possibility of a spontaneous ICA dissection. A carotid plaque MRI is beneficial in the differential diagnosis. Conservative management may benefit patients without ischemic symptoms.

BACKGROUND Pure subarachnoid hemorrhage (SAH) in patients with moyamoya disease is a rare occurrence. Three underlying mechanisms have been described previously, except for ruptured aneurysm of the circle of Willis. Herein, the authors describe a novel mechanism: rupture of a perforator aneurysm in moyamoya disease. OBSERVATIONS A 51-year-old man experienced sudden onset of severe headache and vomiting. Computed tomography showed diffuse SAH. Digital subtraction angiography (DSA) showed unilateral moyamoya disease without remarkable etiology of SAH. The patient underwent conservative management with antihypertensive agents. The second DSA on day 17 revealed a slow-filling aneurysm emerging from the basilar top perforating artery. The diagnosis of SAH due to unknown origin was changed to ruptured basilar artery perforator aneurysm (BAPA). The third follow-up DSA on day 159 revealed the resolution of BAPA. LESSONS In the case of pure SAH, it is crucial to consider the possibility of perforator aneurysms due to hemodynamic stress caused by moyamoya disease. Repeated DSA is essential for detecting the lesion.

Background: Whether hematoma expansion after aneurysmal rupture is always a sign of rerupture remains unclear. Hence, the present study aimed to assess the incidence and risk factors of hematoma expansion unrelated to aneurysmal rerupture after endovascular embolization for ruptured cerebral aneurysms. Methods: We included patients who underwent endovascular embolization for ruptured cerebral aneurysms within 48 h after onset at our institution between January 2009 and February 2014. The medical records of 70 consecutive patients were reviewed and analyzed retrospectively. Results: Hematoma expansion unrelated to aneurysmal rerupture occurred in 7 (10%) of 70 patients. Interestingly, four of seven patients had distal anterior cerebral artery (ACA) aneurysms. The interval from onset to aneurysm coiling was shorter in patients with hematoma expansion than in those without (P = 0.040). Conclusion: Early embolization of ruptured ACA aneurysms might increase the risk of hematoma expansion unrelated to aneurysmal rerupture because the procedures were conducted under systemic anticoagulation. It would be better to refer the patient for direct clipping if the patient has a distal ACA aneurysm with parenchymal hematoma at interhemispheric fissure. Delayed coil embolization, which means around 12–18 h delayed, might be another option for ruptured distal ACA aneurysms to prevent hematoma expansion.

BACKGROUND Intraoperative indocyanine green video angiography (ICG-VA) is useful for determining the extent of lesion removal during cerebral arteriovenous malformation (AVM) surgery. The authors described a case of surgical removal of an AVM presenting with early venous filling mimicking a residual nidus on intraoperative ICG-VA. OBSERVATIONS A 7-year-old girl experienced a sudden disturbance of consciousness. Computed tomography revealed right frontal intracerebral hemorrhage. Digital subtraction angiography showed a Spetzler-Martin grade 1 AVM in the right frontal lobe. The patient received surgical removal of the AVM after endovascular embolization. After removal of the nidus, the first intraoperative ICG-VA revealed early venous filling of the cortex around the excision cavity. Additional resection of the cortex around this area was performed. Histopathological examination of the lesion revealed a dilated normal vascular structure without an AVM. LESSONS Early venous filling in the surrounding brain tissue after AVM removal does not necessarily indicate a residual nidus. The need for additional resection of the lesion depends on the eloquence of the area.