While there is a considerable variation in cerebral veins and dural sinuses, some of these variants are referred to as developmental venous anomalies. Venous variants are rarely pathological, but they are sometimes located near intracranial pathologies. In such instances, venous variants can hinder the surgical approach and manipulation of the target lesion. Without preoperative information about the venous variant, extensive bleeding during dural opening and unintended surgical consequences from the formation of venous edema may occur. Therefore, to avoid venous complications, neurosurgeons, including endovascular interventionists, need to be aware of the presence of venous variants to determine the optimal treatment modality (endovascular or open surgery) and surgical approach. Here, we narratively discuss eight venous/dural variants that were found on preoperative three-dimensional computed tomography venography and emphasize the importance of avoiding unexpected venous complications.

Background: Neurothrombectomy is widely accepted as the standard treatment for acute ischemic stroke caused by a large-vessel occlusion. However, the optimal management of large-vessel occlusion resulting from intracranial atherosclerotic disease remains to be determined.

Methods: A retrospective analysis of eight patients treated at two institutions between April 2012 and July 2019 was conducted. Their demographic, clinical, and radiographic presentations and clinical outcomes were studied. The functional outcomes were assessed using the modified Rankin Scale after rehabilitation or discharge.

Results: Five patients were men and three were women. The occluded vessels were the middle cerebral artery in four patients and the basilar artery in the other four. The median age was 75.5 years (range 57-93 years). Neurothrombectomy was performed in five patients as first-line treatment. In two patients, complete recanalization was achieved by intravenous thrombolysis alone. In one patient, percutaneous transluminal angioplasty was performed without successful recanalization. Re-occlusion or flow stagnation after successful recanalization occurred in four patients (57%) within 3 days, in all of whom an intracranial stent was permanently placed. In another patient with basilar artery atherosclerosis, percutaneous transluminal angioplasty for residual stenosis after successful neurothrombectomy was performed on day 19 of the hospital stay. Favorable outcomes were achieved in five (62.5%) patients, and mortality was observed in two of four patients with basilar artery occlusion.

Conclusions: Early re-occlusion within 72 hours after successful recanalization via neurothrombectomy or intravenous thrombolysis was common in patients with intracranial atherosclerosis-related occlusion. A rescue stent procedure seems reasonable as the last resort following the failure of standard treatment.

The major risk of ruptured brain arteriovenous malformations (rAVMs) is the occurrence of recurrent strokes. Long-term follow-up data of consecutive 394 patients who underwent SRS between 1990 and 2016 in our institution were analyzed to evaluate the role of stereotactic radiosurgery (SRS) for rAVM treatment. The mean follow-up period was 138 months. Embolization and surgical resection were performed before SRS in 11% and 15% patients, respectively. The 5-year cumulative obliteration rates were 79%, 97%, and 73% for SRS alone, SRS with prior resection, and SRS with prior embolization, respectively. Prior resection was associated with better obliteration rates than SRS alone or prior embolization. Prior embolization was not associated with worse obliteration rates. The annual post-SRS re-bleeding rate during the latency period was 2.0%. The significant neurological event (SNE)-free rate was 95% at 10 years. Difference among interventional modalities in the re-bleeding rate and SNE-free rate was absent. The present study indicated that SRS is safe and effective for rAVMs as a single treatment modality, as well as an adjunct for post-surgical residual lesions.

Objective: We aimed to determine the safety and validity of clipping middle cerebral artery (MCA) aneurysms (MCA-AN) using the distal sylvian approach and securing the MCA horizontal segment (M1) from the dorsal or ventral side, from the viewpoint of the relationship between M1 morphology and surgical technique.

Patients and Methods: We used preoperative digital subtraction angiography or computed tomography angiography to analyze M1 morphology in patients who underwent MCA-AN clipping during a period of approximately nine years. Differences in proximal control during surgery were assessed using the intraoperative videos. Patients with distal, large or giant (maximum diameter ≥ 12 mm), fusiform, thrombosed, or multiple aneurysms were excluded, leaving 119 patients. A convex arcuate M1 or a straight M1 in which the angle between the aneurysm neck and the internal carotid artery bifurcation was ≥ 10° downwards was defined as upward convex. A straight M1 with an angle ＜ 10° upwards or downwards was defined as horizontal. A concave arcuate M1 or a straight M1 with an angle ≥ 10° upwards was defined as downward convex.

Results: Among the patients, 84 (71%), 26 (22%), and 9 (8%) had upward convex, horizontal, and downward convex M1, respectively. The intraoperative videos showed that most of the upward convex and short M1 were secured from the dorsal side. Some horizontal and downward convex M1 needed to be secured from the ventral side, but problems did not arise while securing it beyond the aneurysm.

Conclusion: Securing M1 from the dorsal side of an MCA-AN by clipping via the distal sylvian approach is safe and valid. Proximal control from the ventral side of the M1 can be safely achieved with the same head and body position, even for some patients with horizontal and downward convex M1.

Objective: Treatment of ruptured blood blister-like aneurysms (BBAs) of the internal carotid artery remains challenging due to the fragility of the aneurysm membrane structure. Here, we report long-term results of ruptured BBAs treated with endovascular coil embolization using a vascular reconstruction stent.

Methods: Four ruptured BBAs in four consecutive patients (one male and three females; mean age, 46 years; age range, 41-50 years) were treated with assisted endovascular coil embolization using a vascular reconstruction stent between September 2013 and February 2017. Treatment results and longterm angiographic and clinical outcomes were retrospectively analyzed.

Results: All four BBAs were treated with stent-assisted coil embolization. Two of the patients underwent a single-stent insertion using the jail and trans-cell technique with a coil, and the rest two underwent a double-overlap stent insertion using the stent in a stent technique. Both patients who underwent overlapping stent placement presented excellent outcomes (modified Rankin Scale, 0) with complete angiographic obliteration of the BBAs. One patient who underwent single-stent placement experienced aneurysm regrowth with and without rebleeding. The recurrent BBA was treated twice with additional coil embolization. No treatment-related complications developed in any of the patients. All four surviving patients exhibited excellent outcomes during the clinical long-term follow-up period (mean, 3.5 years; range, 2-5 years). Complete BBA obliteration and smooth reconstruction of the affected segment of the internal carotid artery were achieved on long-term follow-up angiography during the same period.

Conclusions: Stent overlapping in the ruptured BBA treatment with stent-assisted coil embolization for long-term stabilization to secure the parent artery is important.

Japan’s aging population makes it difficult for clinicians to select the best treatment options for subcortical hemorrhage. This study examined the treatment outcomes of endoscopic hematoma evacuation in the Japanese elderly. (Method) We retrospectively examined the records of 28 elderly patients aged 70 years or older who were treated at our hospital between 2013 and 2019 and had a hematoma volume of ≥ 20 ml. When surgery was selected, hematomas were removed via craniotomy from April 2013 to March 2018 and via endoscopy from April 2018 onward. (Results) Hematomas were managed conservatively in 12 patients and were surgically removed via craniotomy and endoscopy in six and 10 patients, respectively. These groups were not significantly different in terms of age or hematoma size, but relative to craniotomy, endoscopic removal was associated with a shorter duration of hospitalization (72.88 ± 36.16 vs. 130.00 ± 29.00 days [mean ± SD]; p = 0.014), a comparable Functional Independence Measure score one month after surgery (22.40 ± 2.30 vs. 25.50 ± 4.70), and a lower modified Rankin Scale score at discharge (3.90 ± 0.50 vs. 5.17 ± 0.31). However, nine of 10 patients who underwent endoscopic hematoma removal were able to begin rehabilitation the day after surgery and quickly improved with respect to the baseline in terms of food consumption and neurological symptoms, especially the speech. The degree of improvement in the Glasgow Coma Scale scores after one month was significantly greater in patients who underwent endoscopy than in those who received conservative treatment (mean of 1.70 ± 0.67 vs. 0.50 ± 1.24; p = 0.048) (Conclusion) Endoscopic hematoma removal in the subacute phase of subcortical bleeding was comparable to traditional craniotomy in terms of treatment and functional outcomes in Japan’s elderly population, but was superior in several aspects, including less invasiveness, the ability to be performed under local anesthesia, and shorter duration of hospitalization.

Purpose: Carotid artery stenosis (CS) is occasionally observed during preoperative examinations for cardiovascular disease. In 2016, our institution introduced transcatheter aortic valve implantation (TAVI) as a treatment for severe aortic valve stenosis (severe AS). Here, we report a retrospective examination of patients treated with carotid endarterectomy (CEA) for CS found during preoperative examinations for TAVI.

Materials and Methods: Between April 2016 and August 2018, 37 CEA procedures were performed at our institution. Within this group, a retrospective examination compared patients with CS who were diagnosed during preoperative examination for TAVI (Group A) to all patients who received CEA treatment (Group B).

Results: Five patients (five lesions; mean age 79 years, 20% female) were classified into group A, and 30 patients (32 lesions; mean age 71 years; 9% female) were classified into Group B. The median North American Symptomatic Carotid Endarterectomy (NASCET) for Group A was 79% compared to 66.5% in Group B (p = 0.033). Overall, group A tended to experience a relatively better outcome, despite older mean age and a higher percentage of severe stenosis. Preoperatively, most patients reported a modified Rankin Scale (mRS) score of 0 (Group A=40%, Group B=44%) or 1 (Group A=40%, group B=25%), with 20% of patients in Group A and 19% of patients in Group B reporting an mRS score of 2. None of the patients in Group A and 12% of the patients in group B reported an mRS score of 3. At discharge, a greater proportion of patients reported an mRS score of 0 (Group A = 60%, Group B= 53%) or 1 (Group A=20%, Group B=25%). While 20% of patients in group A and 16% of patients in Group B reported an mRS score of 2 at discharge, 6% of patients in Group B reported a worsened mRS score of 4 (0% Group B, no reported mRS score of 3).

Discussion and Conclusion: Among patients with severe AS, the CAS procedure as treatment for CS is typically not recommended, as it may result in a rapid decrease in blood pressure, causing myocardial ischemia. In contrast, CS may be a risk factor for cerebral infarction during surgical treatment of severe AS. There is no current agreement on whether treating cases of CS with severe AS is safe and on which stenosis should be treated first. Our cases suggest that CEA treatment for CS in patients who also present with severe AS can be safely combined with TAVI after careful discussion with the patient.

We report a case of multiple cerebral aneurysms that ruptured sequentially. A 50-year-old woman with untreated hypertension, alcohol consumption, and smoking habits experienced a sudden, severe headache at work and visited our hospital. Computed tomography (CT) revealed mainly subarachnoid hemorrhage in the basal cistern (WFNS Grade I, Fisher Group III). An irregular 6-mm aneurysm in the left middle cerebral artery bifurcation and a 4-mm aneurysm in the left distal anterior cerebral artery (A2-3) were observed on three-dimensional computed tomography angiography (3D-CTA). Based on the distribution of subarachnoid hemorrhage, and the size and shape of the cerebral aneurysms, we considered the ruptured of a left middle cerebral artery bifurcation aneurysm and performed clipping of the aneurysm by left front-temporal craniotomy on the visit day. The postoperative course was good, but she had a severe headache again on day 5 after the subarachnoid hemorrhage. Repeated CT and 3D-CTA showed an intracerebral hematoma in the left frontal lobe, worsening subarachnoid hemorrhage, and an increased aneurysm size in the left A2-3. We performed clipping of the aneurysm via bilateral frontal craniotomy on the same day. The postoperative course was uneventful, and she was discharged with mildly higher brain dysfunction. Because there are few such case reports, we reviewed the literature and considered the strategy employed in this case. In the treatment of multiple cerebral aneurysms with subarachnoid hemorrhage, it should be noted that the treatment was initially decided according to the distribution of subarachnoid hemorrhage, the size and shape of the cerebral aneurysm, and MRI vessel wall imaging, and that rupture of aneurysm may occur sequentially in a short period of time.

Introduction: Recent studies using computational fluid dynamics (CFD) have indicated that cerebral aneurysm rupture points more likely have low wall shear stress (WSS) and high oscillatory shear index (OSI). In this study, we evaluated if WSS, OSI, and a newly developed parameter─standardized pressure difference (SPD)─were related to aneurysmal wall thinning and characterized the local hemodynamics at the rupture point.

Case presentation: A case of ruptured anterior communicating artery aneurysm in which computed tomography angiography (CTA) clearly depicted the rupture point was studied. A patient-specific geometry model was generated using 3D-CTA, and the rupture point was defined by extravasation of the contrast medium at the left lateral wall of the dome. A mesh was generated using ANSYS ICEM CFD (ANSYS, Inc. USA) and numerical modeling was performed using ANSYS CFX 19.2 (ANSYS, Inc. USA). WSS, OSI, and SPD were calculated at both the rupture point and the aneurysm dome.

Results: Visualization of three hemodynamic parameters revealed that the rupture point had unique local hemodynamic characteristics including low WSS, high OSI, and elevated SPD.

Conclusion: Low WSS at the rupture point was reconfirmed as previous reports. High OSI was colocalized in the area of elevated SPD. The coexistence of these three hemodynamic parameters might have a significant role that affects destructive remodeling and triggers aneurysm rupture.

A 37-year-old man suffered a right hemispheric watershed infarction due to moyamoya disease (MMD). Single-photon emission computed tomography (SPECT) revealed a decrease in the cerebrovascular reserve (CVR) mainly in the left hemisphere. Cerebral angiography revealed the presence of a steal phenomenon from the right anterior cerebral artery (ACA) territory to the left ACA territory via the anterior communicating artery. He underwent left revascularization surgery four months after his first visit, and the postoperative course was uneventful. SPECT three months after the surgery revealed an increase in the CVR, but it was still insufficient. Furthermore, we planned a revascularization surgery for the other side. However, the surgery was postponed because of an inflammatory response caused by a periodontal disease. SPECT performed 18 months after the surgery revealed normalized CVR in both the cerebral hemispheres.

Based on the findings of SPECT, this is the first case to report an improvement in CVR in the hemisphere contralateral to the side where revascularization surgery for MMD was performed.

Dural arteriovenous fistulas (dAVFs) of the lesser sphenoid wing region are rare. We report a case of a dAVF of the lesser sphenoid wing region with leptomeningeal drainage.

A 79-year-old man consulted the Department of Neurosurgery for examination of a dAVF of the anterior cranial fossa, which was incidentally revealed on magnetic resonance imaging. Angiography demonstrated a dAVF of the lesser sphenoid wing region; the fistula was supplied by the recurrent meningeal artery (RMA) via the ophthalmic artery and the inferolateral trunk (ILT) from the left internal carotid artery. Multiple feeders were noticed originating from the left external carotid artery, such as the artery of foramen rotundum (AOR), accessory meningeal artery (AMA), and middle meningeal artery (MMA). The fistula drained into the deep middle cerebral vein via the uncal vein and the frontal cortical vein via the superficial middle cerebral vein, which had varices. The patient was scheduled for endovascular treatment, and transarterial embolization (TAE) was performed. The RMA, ILT, and AOR were occluded using platinum coils, while the AMA was occluded using n-butyl-2-cyanoacrylate (NBCA). The fistula was completely embolized via the MMA using NBCA. No adverse events were noticed, and the fistula was successfully obliterated.

dAVFs of the lesser sphenoid wing region are rare, and TAE using NBCA is a useful treatment for this condition.