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Fenestration of the A1 segment of the anterior cerebral artery is a rare vascular anomaly with a high risk of saccular aneurysm at the proximal end of the A1 fenestration. These aneurysms have a high risk of rupture. However, conventional surgical clipping can be technically challenging due to the anatomical characteristics. We report a case of A1 fenestration with a ruptured aneurysm wherein we successfully achieved complete obliteration of the aneurysm with a new “single-lane” clipping technique. A 64-year-old woman presented with a ruptured saccular A1 aneurysm at the proximal end of an A1 fenestration, resulting in subarachnoid hemorrhage. Microsurgical clipping was attempted; however, adequate exposure of the aneurysm could not be achieved. The recurrent artery of Heubner originated near the distal end of the lateral limb of the A1 fenestration. The lateral limb of the A1 fenestration had no perforating arteries, according to surgical examination. Thus, the aneurysm neck and lateral limb were concurrently obliterated using a nonfenestrated clip, preserving the medial limb of the A1 fenestration. The antegrade flow of the recurrent artery of Heubner was detected using the retrograde flow of the distal part of the lateral limb of the A1 fenestration during intraoperative indocyanine green video angiography. The postoperative course was uneventful without any evidence of ischemic stroke. For A1 aneurysms arising from the proximal end of the A1 fenestration, this technique may be a useful treatment option. Before using this technique, careful surgical exploration should be performed to assess the A1 perforating arteries.

We report a case of a 48-year-old female who presented with abulia and headaches. Head CT (HCT) demonstrated a left caudate intracerebral hemorrhage (ICH) with extension into the left lateral ventricle. Diagnostic cerebral angiogram showed a left distal medial lenticulostriate artery (MLSA) aneurysm with remote left parietal Spetzler-Martin grade 3 arteriovenous malformation (AVM). The patient underwent an endoscope-assisted transcortical-transventricular approach to the distal MLSA aneurysm with complete excision and evacuation of the intraventricular hemorrhage (IVH) postoperatively; the patient had no further neurologic deficits and recovered well from her initial hemorrhage. Ruptured MLSA aneurysms are a very rare cause of spontaneous ICH. Urgent treatment of these aneurysms is needed to prevent further rebleeding. We present a novel operative technique utilizing an endoscope-assisted transcortical-transventricular approach to a ruptured distal MLSA aneurysm with successful excision of the aneurysm.

Introduction Distal medial lenticulostriate artery (LSA) aneurysms associated with isolated intraventricular hemorrhage (IVH) are extremely rare. We report a very rare case of the isolated IVH due to the rupture of the distal medial LSA pseudoaneurysm that was not visible at the initial angiography but later emerged and grew. Case Report A 61-year-old woman with a history of hypertension had sudden onset of severe headache and mild consciousness disturbance. The computed tomography scan revealed the IVH, but the initial angiographies showed no evidence of aneurysm. The follow-up magnetic resonance imaging revealed that an intraventricular mass, arising from the right distal medial LSA, emerged and grew into the right anterior horn. Considering the risk of rebleeding, we resected the mass lesion via the transsulcal transventricular approach. The postoperative imaging showed complete obliteration of the mass lesion. Histopathological analysis indicated the pseudoaneurysm. The patient was discharged without any neurological deficit. Conclusions The careful and repetitive follow-up imaging should be done in the cases with isolated IVH even if the initial image evaluations are unrevealing. The transsulcal transventricular approach can be the most minimally invasive surgical option for intraventricular lesion.

Background Medial lenticulostriate artery (MLSA) aneurysms are rare; to our knowledge, only 2 cases without an association with moyamoya disease have been documented. We treated a ruptured dissecting aneurysm of the distal MLSA surgically using a tube retractor. Case Description A 66-year-old woman suffered a sudden-onset disturbance in consciousness. Computed tomography showed diffuse subarachnoid hemorrhage and a dense intraventricular hematoma associated with acute hydrocephalus. She underwent emergent ventricular drainage. Angiography revealed a 3-mm distal MLSA aneurysm. On repeat angiographs, the aneurysm had not disappeared. Because the stenotic, narrow structure of the proximal portion of the MLSA disallowed the endovascular approach, we performed direct surgery via the transventricular approach using a tube retractor. The aneurysm on the intraventricular surface of the anterior horn of the lateral ventricle adjacent to the caudate nucleus was exposed. We resected the aneurysm under transcranial motor-evoked potential monitoring because neck clipping would have endangered the patency of the MLSA. Her postoperative course was uneventful. The pathologic diagnosis was ruptured dissecting aneurysm. Conclusions There is no definitive strategy to treat distal MLSA aneurysms. Our experience illustrates that natural healing of the vessel wall cannot be expected in all cases. Therefore, less-invasive direct surgical as well as endovascular treatment should not be ruled out in patients with ruptured distal MLSA aneurysms.

BACKGROUND Aneurysms arising from the proximal portion of the anterior cerebral artery (A 1 : 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. A 1 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 A 1 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 A 1 fenestration. All nine patients had an excellent outcome after surgery. CONCLUSION A 1 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.

Precommunicating (A1) segment aneurysms of the anterior cerebral artery are rare and often pose technical challenges for coil embolization due to their distinctive configurations. Clinical and radiologic outcomes of treating such aneurysms through endovascular coil embolization are presented herein. Data accruing prospectively from May 2002 to August 2013 yielded 48 patients harboring 50 A1 segment aneurysms, each classified as proximal, middle, or distal by location. Clinical outcome of the patients and morphological outcome of the aneurysms were assessed, with emphasis on technical aspects of treatment. The aneurysms studied occupied either proximal (n = 39), middle (n = 6), or distal (n = 5). Proximal aneurysms were largely directed posteriorly (80 %), and most (97 %) were devoid of branches. Middle and distal aneurysms were associated with the medial lenticulostriate artery, cortical branches, or fenestrations. The preshaped “S” and steam-shaped “S” microcatheters facilitated aneurysm selection in 60 % of lesions. Single-microcatheter technique was most commonly applied for coil embolization (62 %), followed by balloon protection (16 %). Successful aneurysmal occlusion could be achieved in 76 % of the patients, with no procedure-related morbidity and mortality. At final follow-up (mean interval, 29.9 months), stable aneurysmal occlusion was sustained in 93 % of the patients (40/43). A1 segment aneurysms are amenable to safe and efficacious endovascular coil embolization by adjusting procedural strategy to accommodate distinctive anatomic configurations.

Background: Isolated intraventricular hemorrhage (IVH) secondary to lenticulostriate artery aneurysm rupture is extremely rare. Thus, the diagnostic imaging modalities and therapeutic interventions utilized in the management of such cases are not clearly defined. Case Description: Here we describe a case of isolated or primary IVH (PIVH) in a 71-year-old woman presenting with severe headache. Emergent catheter cerebral angiography, performed after nondiagnostic computed tomography angiography (CTA), revealed the bleeding source to be a 4 × 2.6 mm distal medial lenticulostriate artery aneurysm that ruptured directly into the lateral ventricle. The poorly accessible location of the aneurysm for both endovascular and direct surgical treatment argued for conservative management. A good clinical outcome was obtained with rapid angiographic resolution of the ruptured aneurysm. Conclusion: Thus, lenticulostriate artery aneurysm rupture must be given diagnostic consideration in cases of isolated IVH. Emergent catheter cerebral angiography should be performed in cases such as this when noninvasive imaging is unrevealing. Conservative management may be a reasonable therapeutic option in patients with this kind of aneurysm, and spontaneous resolution can be observed.

We report a rare case of an idiopathic pseudoaneurysm causing intraventricular hemorrhage (IVH). A 28-year-old man presented with sudden onset of severe headache. He underwent external ventricular drainage for an isolated IVH in the right lateral ventricle. Digital subtraction angiography (DSA) revealed that the aneurysm (7.5×4.5 mm) arose from the distal part of the medial lenticulostriate artery. Following removal of the external ventricular drainage catheter, the aneurysm decreased in size (4.0×2.3 mm). However, follow-up DSA revealed a slightly enlarged aneurysm (4.2×3.2 mm) with morphologic change. The aneurysm was clipped via the interhemispheric transcallosal approach, but postoperative DSA revealed a residual aneurysm sac beside the clips. Given the risk of rebleeding, a second operation was planned for complete resection of the aneurysm. After revised craniotomy and careful dissection of the caudate nucleus, the aneurysm sac was completely resected. Histopathological examination revealed that the aneurysm was a pseudoaneurysm. The patient recovered without any neurological sequel and was discharged. To the best of our knowledge, this is the first reported case of an idiopathic lenticulostriate artery pseudoaneurysm protruding into the right lateral ventricle and causing an IVH that was successfully treated with microsurgical resection.