A Recurrent Large Posterior Cerebral Artery Aneurysm Successfully Treated with Parent Artery Occlusion Using Somatosensory-Evoked Potential: A Case Report.

Objective: Treatment of large posterior cerebral artery (PCA) aneurysm involving the P1-P2 segment is difficult by both neurosurgery and endovascular treatment. Balloon occlusion test (BOT) to identify precise peripheral collateral flow is difficult prior to parent artery occlusion (PAO). Besides, PAO at the aneurysm at this location can cause peripheral cortical infarction of the occipital and temporal lobes and/or perforator infarction involving the midbrain and thalamus perfused by the perforating artery arising from the P1-P2 segment. However, detection of the perforator during PAO is difficult. Case Presentation: The patient was a 49-year-old woman. At the age of 43 years, a right large PCA aneurysm was discovered in the right P1-P2 segment. A simple technique coiling was performed. As recurrence was identified 1 year later, embolization was performed using a same procedure. Since further recurrences were later found, a third round of treatment was planned. Somatosensory-evoked potential (SEP) was recorded as intraoperative electrophysiological monitoring. Tortuosity of the right PCA was observed at the aneurysm neck and the distal right PCA could not be secured. We could neither perform stent-assisted coil embolization nor BOT in the right PCA. Hence, we inflated the balloon in the basilar artery and checked the collateral circulation routes retrograde into the right PCA from the right middle cerebral artery via a leptomeningeal anastomosis. PAO was performed on the right P1-P2 segment at the aneurysm neck. The signal of the SEP was not decreased, and the aneurysm was not visualized. Another coil was added to strengthen the PAO to the right P1 segment, which decreased the SEP amplitude in the extremities by 3 minutes after. As the last coil was thought to be occluding the perforator branching from the right P1 segment, it was removed without detaching. The SEP amplitude began to improve and recovered by 9 minutes after. There was no postoperative deficit. No recurrence of aneurysm was observed on MRA 9 months postoperatively. Conclusion: During PAO at the P1 segment of large PCA aneurysm involving the P1-P2 segment, SEP may be helpful to prevent perforator infarction, even if perforating artery originating from the proximal portion of the aneurysm was not detected by angiography.

Stent-Assisted Coil Embolization of Ruptured Blood Blister-Like Aneurysm of the Basilar Artery: A Case Report and Literature Review.

Objective: Blood blister-like aneurysms (BBA) often develop on the anterior wall of the internal carotid artery, and few cases have been reported at other sites. We report a case of stent-assisted coil embolization in the acute phase for a ruptured BBA of the basilar artery. Case Presentation: A 53-year-old woman underwent emergency stent-assisted coil embolization for subarachnoid hemorrhage due to a ruptured BBA in the main trunk of the basilar artery. Seven months after the operation, cerebral angiography confirmed no recurrence and a good clinical course. Conclusion: Stent-assisted coil embolization for BBA may be one treatment option.

[Ruptured Posterior Inferior Cerebellar Artery Communicating Artery Aneurysm:A Case Report].

The posterior inferior cerebellar artery(PICA)communicating artery is a fine tortuous artery that interconnects the bilateral vermian branches of the distal PICAs. Aneurysms of this anastomotic vessel have been reported in only seven cases(including ours)in the available literature. The PICA communicating artery supplied collateral blood flow to the contralateral vermian territory in all seven cases. A 51-year-old man presented with a rare PICA communicating artery aneurysm(which manifested as a hematoma in the fourth ventricle)and mild subarachnoid hemorrhage at the cerebellomedullary fissure. Angiography revealed a hypoplastic right PICA and a PICA communicating artery from the left PICA that supplied the right vermian territory; the ruptured aneurysm originated from this vessel. Aneurysm trapping is associated with the risk of cerebral infarction of the right vermian territory. We concluded that the distal part of the telovelotonsillar segment could be sacrificed because the right anterior inferior cerebellar artery and the superior cerebellar artery would supply collateral blood flow; therefore, we attempted trapping in this case. A bilateral midline suboccipital approach was used, and we detected a reddish fusiform aneurysm at the top of a hairpin curve of the PICA communicating artery in the uvula of the cerebellar vermis. The aneurysm was trapped and removed without complications. Histopathological evaluation confirmed findings of a true aneurysm. Congenital vulnerability of the arterial wall and hemodynamic stress are considered contributors to PICA communicating artery aneurysms. Preservation of the affected vessel is difficult in patients in whom aneurysmal clipping is challenging. Other vessels tend to establish collateral blood flow to the contralateral vermian territory in such cases. Trapping is a simple and effective therapeutic strategy for these aneurysms.

Five Cases of High-grade Arteriovenous Malformation Treated by Presurgical Embolization through the Anterior Choroidal Artery.

Objective: In cases of cerebral arteriovenous malformation (AVM) in which perforators are involved as feeder, hemostasis is difficult during surgical removal and postoperative hemorrhage may develop. If possible, presurgical embolization should be performed. However, when the anterior choroidal artery (AChA) is the feeder, the risk of embolization is particularly high, and there are few reports describing this situation. Authors report the treatment results of five cases of AVM in which a single operator performed presurgical embolization through the AChA and describe the technique with a review of the literature. Case Presentations: Of the five total cases (three men and two women; average age was 43.4 years [28-68 years]), one case presented with hemorrhage, two with epilepsy, the other ones with headache and trigeminal neuralgia, respectively. The lesions were located in the frontal lobe in one case and in the temporal lobe in four cases. On the Spetzler-Martin (SM) grading scale, four cases were grade III and one was grade IV. The eloquent area was involved within the nidus in four cases. Multimodal treatment was planned because all cases were high-grade AVM. Authors thought that performing presurgical embolization through the AChA would reduce the overall risk of treatment and performed the presurgical embolization. The embolization was possible in all cases, and the AVM was not angiographycally visible through the AChA in three cases. The blood flow through the AChA was reduced in two cases. All cases were awake immediately after embolization and no case had neurological symptom after embolization. CT or MRI after embolization revealed asymptomatic infarction in two cases. The AVM was removed safely without difficulty including hemostasis. Conclusion: In this series, there were no morbidity and embolization was performed relatively safely. Embolization through the AChA was suggested to be an effective treatment, but careful consideration is required in each individual case.

[Stent-in-Stenting for In-Stent Stenosis after Carotid Artery Stenting:A Report of 2 Cases].

Standard strategy for the treatment of subacute in-stent stenosis after carotid artery stenting remains controversial. We report the successful application of stent-in-stenting in 2 patients with subacute in-stent stenosis of the internal carotid arteries (ICA). The postoperative courses of both patients were uneventful, and the patency of the ICA was confirmed at the 2-year follow-up. In this study, medical treatment was not effective, and therefore, stent-in-stenting was used as an alternative treatment for subacute in-stent stenosis.

[Chronic subdural hematoma organized over a short period of time with spontaneous intracranial hypotension: a case report].

Spontaneous intracranial hypotension (SIH) can develop after cerebrospinal fluid (CSF) leakage and is accompanied by various symptoms, including headache and neck pain. In recent years, cases of chronic subdural hematoma (CSDH) that develop concomitantly with SIH have been encountered occasionally. Although various reports regarding the priority of treatment exsist, a conclusive opinion has yet to be given. Here, we present a rare case of CSDH that developed concomitantly with SIH in which the hematoma became organized over a short period of time. Organized CSDH results from impairment of the microcirculation due to metabolic or circulatory dysfunction or inflammation after trepanation. The disease is believed to require craniotomy for treatment, while SIH is frequently treated with an epidural blood patch, which may require repeated procedures to achieve success. If CSF leakage cannot be improved, the concomitant CSDH may become organized. Therefore, it is important to thoroughly discuss the therapeutic options in individual cases.

[A case of aneurysmal subarachnoid hemorrhage associated with bilateral common carotid artery occlusion].

Cerebral aneurysm may occur in some cases of major cerebral artery occlusion. However, according to our search of the literature, only four cases of aneurysmal subarchnoid hemorrhage (SAH) associated with bilateral common carotid artery occlusion (CCAO) have been reported in addition to the case we report here with a summary of the previously reported cases. A healthy 82-year-old female was found unconscious and admitted to our hospital where her neurological state was diagnosed as Hunt & Kosnik grade II, World Federation of Neurosurgical Societies grade II. General physical examination yielded no abnormal findings. A computed tomography (CT) scan of the head revealed a subarachnoid hemorrhage (Fisher's classification group 3). An aortogram demonstrated the presence of both vertebral arteries (VA), but the origins of the common carotid arteries (CCAS) were not visible at all. The left vertebral angiogram (VAG) revealed anastomosis between the muscle branch of the VA and the occipital artery, with retrograde blood flow through the external carotid artery supplying the internal carotid artery (ICA). These findings were also visible on the right VAG, but there was severe stenosis of the C2 portion of the right ICA. The right enlarged posterior communicating artery (Pcom) supplied the right ICA. Two saccular aneurysms arising from the junction of the right posterior cerebral artery (PCA) and the enlarged right Pcom and the P2 segment of right PCA, respectively were also observed. Aneurysm formation in this case was probably caused by hemodynamic stress secondary to bilateral CCAO induced by arteriosclerosis.