Large but non-giant cerebral aneurysms are usually treated with neck clipping, which carries larger risk compared with clipping for smaller aneurysms.
To maximize the benefit of clipping over the risk, the authors have been cautious about the following points. 1) Preoperative evaluation of not only the aneurysm morphology but also collateral blood flow during temporary occlusion of the parent artery proximal to the aneurysm. 2) Positioning and craniotomy to minimize brain retraction. 3) Monitoring of motor evoked potential to tailor the temporary occlusion time. 4) Utilization of the retrocarotid space by dissecting vessels from the temporal lobe facing the Sylvian fissure and retracting the temporal lobe posteriorly. This is especially important for internal carotid-posterior communicating (IC-Pcom)/anterior choroidal (ACh) and basilar terminal aneurysms in terms of visualization of ACh, perforators of Pcom, and the aneurysm neck behind the IC, as well as to obtain a wide working space even after temporary clipping of the proximal basilar artery. 5) Bypass surgery can be used to prolong permissible temporary occlusion time or to provide permanent blood flow in conjunction with parent artery occlusion, when clipping is considered too risky. 6) Intraoperative reassessment of the surgical strategy by an endovascular surgeon is sometimes valuable to decide whether the clipping should be accomplished or abandoned, with a change to endovascular therapy.

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Nine cases of large/giant aneurysm arising from the terminal portion of the internal carotid artery (ICA) were analyzed. The presenting symptoms were subarachnoid hemorrhage in 6 cases and visual disturbance in 2 cases. One case was asymptomatic. Eight cases were treated with angioplastic clipping by using various decompression methods. One case with marked atherosclerosis in the aneurysm wall was treated with proximal occlusion of the ICA with high-flow bypass. Intraoperative monitoring of motor-evoked potential (MEP) was performed in 5 of the 9 cases. Three of the 4 cases treated without MEP monitoring had permanent ischemic complications. Intraoperative MEP monitoring is useful to prevent ischemic complications caused by insufficient flow in the anterior choroidal artery during ICA aneurysm surgery, especially in cases treated with clipping using the suction decompression method. An experienced surgical team is important to treat emergency cases.

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The treatment of complex internal carotid artery (ICA) aneurysms is still a controversial issue. This study aimed to evaluate the safety and efficacy of a surgical strategy using the bypass procedure in such patients. We retrospectively reviewed the clinical and radiological records of 50 consecutive patients with 52 complex ICA aneurysms who underwent bypass surgery. In this study, we divided the ICA into 3 segments based on the origin of the ophthalmic artery (OpthA) and posterior communicating artery (PComA). All patients with an aneurysm located in the portion proximal to the OpthA (segment 1) were treated with bypass and proximal ICA occlusion, and only 1 patient (5.2%) experienced an ischemic complication. Among patients with an aneurysm located between the OpthA and PComA (segment 2), 14 were treated with bypass and trapping, and 10 were treated with clipping under bypass. Among these, 3 (12.5%) had an ischemic complication and 1 (4.2%) had a hemorrhagic complication. Among patients with an aneurysm located distal to the PComA (segment 3), clipping under temporary bypass was performed in 2, clipping with bypass and proximal occlusion in 4, trapping in 2, and bypass and proximal occlusion in 1. However, 4 of 9 (44.4%) patients had an ischemic complication. Finally, 41 of 50 (82.0%) patients showed a favorable outcome (modified Rankin scale 0-2) in this series. In conclusion, the results of our surgical strategy using a bypass procedure were acceptable; however, ischemic complications were a persistent problem in aneurysms located distal to the PComA.

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This article reviews historical aspects of surgical revascularization for moyamoya disease and the concept of indirect, direct, and combined bypass surgery. The article also precisely describes the surgical technique and perioperative management of superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis and encephaloduromyoarteriopericranial synangiosis (EDMAPS) based on the author's 18-year experience.

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Patients who present with a large intracerebral hematoma (ICH) associated with a ruptured aneurysm usually require urgent clot evacuation as well as aneurysm obliteration, in order to lower the intracranial pressure as early as possible. However, controversy persists regarding the optimal approach for the obliteration of an anterior communicating aneurysm (Acom AN) with massive ICH. The aim of this study was to determine a suitable approach among a variety of surgical procedures for these aneurysms.
The records of 38 patients with ruptured Acom AN with large frontal ICH treated with hematoma evacuation and aneurysm clipping between April 1996 and March 2015 were retrospectively reviewed. The adopted approaches were classified as follows: hematoma-side pterional (PT, 7 patients), contralateral hematoma-side pterional (c-PT, 19 patients), interhemispheric (IH, 9 patients), and transhematoma approach (TH, 3 patients). Preoperative patient characteristics were similar in the four approach groups.
The overall outcomes at discharge according to the Glasgow Outcome Scale (GOS) are summarized as follows: Good Recovery was obtained in 42.1%, Moderately Disabled status in 39.5%, and Severely Disabled status in 13.2%, while the mortality rate was 5.3%. Significant factors associated with poor outcome included increasing age, incomplete evacuation of hematoma, occurrence of infarction due to vasospasm, hydrocephalus, and the use of the c-PT approach.
We therefore recommend aggressive hematoma evacuation and aneurysm obliteration using appropriate approaches such as the TH technique rather than the c-PT procedure for ruptured Acom AN with massive frontal ICH.

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A 52-year-old man presented with sudden severe headache. He was diagnosed with subarachnoid hemorrhage due to ruptured anterior wall aneurysm of the left internal carotid artery (ICA). Left frontotemporal craniotomy was performed followed by superficial temporal artery-middle cerebral artery (STA-MCA) double bypass, and the ICA was trapped just proximal to the posterior communicating artery with intracranial clipping, while simultaneously occluding the proximal ICA by endovascular coil embolization. The outcome of this patient demonstrates that hybrid operations with surgical clipping and endovascular coil embolization in a single stage can offer effective treatment.

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We report two cases of internal carotid-posterior communicating artery aneurysm (IC-PC AN) located above the IC bifurcation. The first case was a 51-year-old woman with subarachnoid hemorrhage (SAH) caused by a ruptured high-lying IC-PC AN projecting superiorly. The aneurysm was behind the arteries and perforators completely in the pterional transsylvian route; therefore, the clip was applied from the carotid-optic triangle confirming the blade tip of the clip through the supracarotid triangle. The second case was an 81-year-old man with SAH because of a ruptured high-lying IC-PC AN projecting posteriorly. The aneurysm was obscured by arteries and the temporal lobe in the pterional transsylvian route, so was visualized and clipped by retracting the arterial structures and temporal lobe, similar to an anterior temporal approach.
IC-PC ANs above the IC bifurcation are located behind the surrounding structures in the operative field. Therefore, selection of the proper approach according to the anatomical location of the IC-PC AN and effective utilization of the space around the IC as the surgical window are important in such cases.

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Cerebral revascularization with high-flow extracranial-intracranial (EC-IC) bypass is generally indicated in patients with complex intracranial aneurysms. This is the first reported case of aneurysm formation followed by rupture occurring on the graft itself, which was constructed to treat a patient with a giant internal carotid artery (ICA) aneurysm. A-78-year-old woman who had undergone right EC-IC bypass using a saphenous vein graft and ligation of the right cervical ICA to treat an unruptured right ICA giant aneurysm 20 years earlier presented with a subarachnoid hemorrhage (SAH). Computed tomography (CT) on admission revealed a ring-like mass in the right temporal lobe with an SAH. Angiography showed a fusiform aneurysmal formation on the graft just before the anastomotic site. We initially performed detachable coil embolization of the aneurysm with a stent in the acute stage. Next, endovascular trapping of the parent artery (saphenous vein graft) and removal of intraaneurysmal thrombus were performed, after we created a new high-flow EC-IC bypass using a radial artery. We report this case along with a review of the literature.

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We report a rare case of infantile cerebral aneurysm that presented with subarachnoid hemorrhage. A 45-day-old female infant developed convulsions accompanied by fever and vomiting. Her various brain scans revealed a subarachnoid hemorrhage in the interhemispheric fissure and a 15mm saccular aneurysm located in the anterior cerebral artery. Neck clipping of the aneurysm was performed. The patient was treated for status epilepticus, delayed cerebral ischemia due to vasospasm, and hydrocephalus with placement of a ventriculoperitoneal shunt. She was discharged with minor left hemiparesis, which did not affect her subsequent life in terms of developmental delay.

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Frontotemporal craniotomy is one of the most commonly practiced operative procedures in craniotomy. We describe our experience with two representative patients in whom conductive hearing loss developed after frontotemporal craniotomy with hemotympanum. We also review the relevant literature. Case 1 was a 69-year-old woman with an unruptured cerebral aneurysm at the bifurcation of the left internal carotid artery and posterior communicating artery. Case 2 was a 69-year-old woman with an unruptured cerebral aneurysm in the left middle cerebral artery. In both cases, clipping surgery was performed using a frontotemporal craniotomy approach. Both experienced hearing loss in the left ear starting a few days after surgery and visited the department of otolaryngology in our hospital. Conductive hearing loss caused by hemotympanum was diagnosed in both cases. We rarely see patients developing hemotympanum after frontotemporal craniotomy. We, herein, examine the causes and countermeasures through anatomical findings.

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We describe the approaches for endoscopic hematoma evacuation for thalamic hemorrhage with ventricular perforation. We suggest minimum invasive surgical approaches to evacuate thalamic hematomas that are divided into the following four types based on the location of the hematoma and ventricular perforation point: Anterior-medial type, posterior-medial type, medial type, and lateral type.
A transcortical intraventricular puncture via the anterior horn of the lateral ventricle is suitable for the anterior-medial type and medial type, via the ipsilateral posterior horn of the lateral ventricle is recommended for the posterior-medial type, and a transcortical puncture via just above the hematoma is suitable for the lateral type of thalamic hematomas.
We suggest that the posterior-medial type is the best indication for endoscopic evacuation; however, appropriately selecting the surgical approach for thalamic hematomas with ventricular perforation may contribute to good post-operative outcome.

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