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Object: The introduction of flow diverters (FDs) has represented a paradigm shift in the management of unruptured cerebral aneurysms (UCA). Flow Re-Direction Endoluminal Devices (FREDs) and Pipeline Embolization Devices (PEDs) have gained widespread popularity. We aimed to investigate the cumulative incidence of aneurysm occlusion. Methods: A total of 195 patients with 199 UCAs were analyzed retrospectively. The outcomes were aneurysmal occlusion during the follow-up, a modified Rankin Scale score of 0–2 at 90-day, additional treatment, and major stroke, and steno-occlusive events of FD. Propensity score-matched analysis was performed controlling for age, sex, aneurysmal size, and location of internal carotid artery (ICA) aneurysm. Non-ICA aneurysms were excluded from matching. Results: During the follow-up period (median, 366 days), complete and satisfactory aneurysmal occlusions were observed in 128 (68%) and 148 (78%) of 189 UCAs in unmatched cohort. The 142 (71 each) propensity score-matched cohort was complied. The FRED group had a higher cumulative incidence of ICA aneurysm occlusion (complete: HR 2.7, 95% CI 1.4–5.1, p=0.0025; satisfactory: HR 2.4, 95% CI 1.1–5.2, p=0.025). Proportion of additional treatment was significantly smaller in the FRED group (OR 0.077, 95% CI 0.010-0.57, p=0.0007). Other outcomes showed no significant differences. Conclusion: Propensity score-matched analysis showed that FRED had a higher cumulative incidence of aneurysmal occlusion in the treatment of unruptured ICA aneurysms. Whether a cumulative incidence of aneurysmal occlusion may differ by the type of FDs warrants further investigation.

BackgroundEndovascular treatment (EVT) is widely accepted for intracranial aneurysms due to its safety and efficacy. However, EVT of ruptured very small intracranial aneurysms (RVSIA) (≤3 mm) is still challenging and the risk-benefit ratio of EVT remains unclear. The aim of this study was to evaluate the safety and efficacy of EVT of RVSIA.MethodsWe performed a systematic review and meta-analysis of the studies on EVT of RVSIA. Pooled prevalence rates were calculated for initial and follow-up complete occlusion rates (Raymond Roy Grade 1), recanalization, retreatment, long-term favorable outcome (modified Rankins scale score 0 to 2 or Glasgow Outcome Scale 4 or 5), procedure-related complications (coil herniation, thromboembolism, and intraprocedural re-rupture), and procedure-related mortality. Pooled odds ratios were calculated to compare these outcomes between simple coiling and stent-assisted coiling (SAC).ResultsOf the 600 studies screened, 24 studies with a total of 1355 RVSIAs treated with EVT were included. The initial and follow-up complete aneurysm occlusion rates were 64% (95% confidence interval [CI]: 52–74%) and 85% (95% CI: 74–92%). The rates of recanalization and retreatment were 6% (95% CI: 3–10%) and 3% (95% CI: 2–4%). The favorable long-term follow-up outcome was observed in 91% (95% CI: 89– 93%) of patients. The rates of coil herniation, thromboembolism, and intraprocedural rupture were 2% (95% CI: 1–8%), 4% (95% CI: 3–6%), and 4% (95% CI: 2–7%), respectively. Mortality was 3% (95% CI: 2–4%). Comparison of outcomes between simple coiling and SAC revealed no significant difference, except for a higher likelihood of recanalization in the coiling group (Odds ratio, 3.51 [95% CI, 1.31–9.45]).ConclusionsOur meta-analysis demonstrates that EVT for RVSIA is a feasible, effective, and safe approach that is associated with favorable clinical outcomes in both the short and long term.

OBJECTIVEPerforator territory infarction (PTI) is still a major problem needing to be solved to achieve good outcomes in aneurysm surgery. However, details and risk factors of PTI diagnosed on postoperative MRI remain unknown. The authors aimed to investigate the details of PTI on postoperative diffusion-weighted imaging (DWI) in patients with surgically treated unruptured intracranial saccular aneurysms (UISAs).METHODSThe data of 848 patients with 1047 UISAs were retrospectively evaluated. PTI was diagnosed on DWI, which was performed the day after aneurysm surgery. Clinical and radiological characteristics were compared between UISAs with and without PTI. Poor outcome was defined as an increase in 1 or more modified Rankin Scale scores at 12 months after aneurysm surgery.RESULTSPostoperative DWI was performed in all cases, and it revealed PTI in 56 UISA cases (5.3%). Forty-three PTIs occurred without direct injury and occlusion of perforators (43 of 56, 77%). Poor outcome was more frequently observed in the PTI group (17 of 56, 30%) than the non-PTI group (57 of 1047, 5.4%) (p < 0.0001). Thalamotuberal arteries (p < 0.01), lateral striate arteries (p < 0.01), Heubner’s artery (p < 0.01), anterior median commissural artery (p < 0.05), terminal internal carotid artery perforators (p < 0 0.01), and basilar artery perforator (p < 0 0.01) infarctions were related to poor outcome by adjusted residual analysis. On multivariate analysis, statin use (OR 10, 95% CI, 3.3–31; p < 0.0001), specific aneurysm locations (posterior communicating artery [OR 4.1, 95% CI 2.1–8.1; p < 0.0001] and basilar artery [OR 3.1, 95% CI 1.1–8.9; p = 0.031]), larger aneurysm size (OR 1.1, 95% CI 1.1–1.2; p = 0.043), and permanent decrease of motor evoked potential (OR 38, 95% CI 3.1–468; p = 0.0045) were related to PTI.CONCLUSIONSDespite efforts to avoid PTI, it occurred even without direct injury, occlusion of perforators, or evoked potential abnormality. Therefore, surgical treatment of UISAs, especially with the aforementioned risk factors of PTI, should be more carefully considered. The evaluation of PTI in the territory of the above-mentioned perforators could be useful in helping predict the clinical course in patients after aneurysm surgery.

Sylvian subpial hematoma (SSH) is occasionally observed in aneurysm subarachnoid hemorrhage (aSAH) when accompanied with the thick clot in the inferior limiting sulcus (ILS). We aimed to determine whether the thickness of the clot in the ILS (TCILS) was an indicator of SSH.Data from 150 consecutive patients with aSAH were retrospectively analyzed. The relationship between TCILS on axial computed tomography (CT) image and intraoperatively confirmed SSH was reviewed. In patients without SSH, the average of the clot thickness in the bilateral ILS was used. The primary outcome was SSH.The median TCILS of the SSH group (n = 18, 12%) was larger than that of the non-SSH group (n = 132, 88%) (21 vs. 2.1 mm, respectively; P0.001). The intraclass correlation coefficients for clot thickness in the right and left ILS between 2 observers were 0.97 (P0.001) and 0.85 (P0.001). The TCILS threshold of ≥6.0 mm was associated with SSH, with a sensitivity of 89% and specificity of 99%. The unadjusted and adjusted odds ratios of the SSH of clot thickness in the affected ILS ≥6 mm relative to clot thickness in the affected ILS6 mm were 263 (95% confidence interval [CI], 46-5063) and 137 (95% CI, 19-3029), respectively.The clot thickness in the ILS on CT image was easily measured and could be a marker of SSH. SSH assessment could be useful in helping us predict the clinical course in patients with aSAH.

During surgical treatment of cerebral aneurysm, thin-walled or severe atherosclerotic aneurysms on the middle cerebral artery are sometimes observed. Owing to the vulnerability or stiffness of the aneurysm, simple neck clipping is usually difficult. We aimed to describe a sling-wrap clipping method using a polyglycolic acid (PGA) sheet for thin-walled or atherosclerotic middle cerebral artery aneurysms. The sling-wrap clipping method was performed in six patients with middle cerebral artery aneurysms. After the distal Sylvian approach, the aneurysm and parent artery were slung up like a baby sling by using a transparent PGA sheet. The aneurysm was directly clipped with the PGA sheet by grasping both ends of the sheet and holding them up. Contrary to the existing wrapping methods, our method could directly obstruct the aneurysm under good visibility through the sheet, thereby avoiding slipping in/out of the clip blade. All cases of the sling-wrap clipping method performed in this study were successful. No problems related to this method were encountered. Aneurysm recurrence, allergic reaction to the PGA sheet, and parent artery stenosis were not observed during the follow-up period. The sling-wrap clipping method using a PGA sheet is safe and another surgical option for thin-walled or atherosclerotic middle cerebral artery aneurysms.

The C1 lateral mass screw (LMS) is widely used as one of the screws for atlantoaxial fixation. Tight bicortical screwing from the posterior to anterior cortical margin of the atlas is recommended. However, important structures, such as the internal carotid artery, are located around this area so precision is required to avoid injuring them. We describe the usefulness of a new electronic conductivity device (ECD) with a pedicle probe and a multi-axis angiography unit for inserting the C1 LMS. Four consecutive patients who were treated with C1 and C2 posterior fixation using an ECD and a multi-axis angiography unit in the hybrid operating room were included. All patients were treated successfully. Seven of eight bicortical screws could be inserted into the perfectly ideal location. The median (interquartile range) distance from the anterior margin of the atlas to the tip of the screw was 0.81 mm (0.43, 1.21 mm). This study suggested that the ECD and multi-axis angiography unit are useful for inserting the C1 LMS safely and tightly.

The transsylvian approach(TSA)and interhemispheric approach(IHA)are two basic and important surgical approaches for the treatment of cerebral aneurysms. The TSA is usually the first choice for treating middle cerebral artery aneurysms but is sometimes used for treating even anterior communicating artery, internal carotid artery, and basilar artery aneurysms. In contrast, the IHA is usually the first choice for treating anterior communicating artery and distal anterior cerebral artery aneurysms. Young inexperienced neurosurgeons may find these approaches difficult to perform without blood loss. Therefore, the aim of this study was to provide useful tips regarding hemostasis, brain retraction, and intraoperative microscope magnification for performing the TSA and IHA without blood loss by using intraoperative photography.

Endovascular therapy (EVT) is safe and effective for acute ischemic stroke (AIS) due to large-vessel occlusion (LVO). However, the influence of the AIS subtype (large-artery atherosclerosis [LAA] or cardioembolism [CE]) on clinical outcome in patients treated with EVT remains unclear. This study aimed to evaluate the differences in clinical results between the two subtypes using data from a multicenter prospective registry (RESCUE-Japan Registry 2).Among 2420 patients in RESCUE-Japan Registry, 682 patients who were diagnosed with LAA or CE were enrolled. The primary outcome was a modified Rankin Scale (mRS) score of 0-2 at 90 days. The secondary outcomes were 90-day mRS 0-1, 0-3, and 6. The relationship between time from onset and clinical outcome was also analyzed.Among the 682 patients, 124 were classified into the LAA group and 558 into the CE group. The baseline National Institutes of Health Stroke Scale score was significantly lower (median 15 vs. 18, p 0.001). At 90 days, mRS 0-2 was observed in 54 of 124 patients (44%) in the LAA group and 232 of 558 patients (42%) in the CE group (p = 0.69). The proportion of patients with mRS 0-2 tended to decrease according to onset-to-puncture time in the CE group but not in the LAA group (pThe rate of good outcome was similar between LVO due to LAA and CE. However, the rate of favorable outcome did not decrease according to onset-to-puncture time in the LAA group.

Distal basilar artery aneurysms (DBAs) consist of basilar apex and basilar artery-superior cerebellar artery bifurcation (BA-SCA) aneurysms. The authors aimed to investigate clinical and radiological differences between two locations and to evaluate the 12-month surgical outcome in unruptured DBAs. Fifty-six consecutive patients who underwent surgical treatment (37 basilar apex and 19 BA-SCA aneurysms) between April 2012 and February 2016 were retrospectively evaluated. In patients with a preoperative modified Rankin Scale score (mRS) of more than 1, neurological worsening (NW) was defined as an increase in one or more mRS. In patients without symptoms, NW was defined as mRS ≥2. The mean age of the patient population was 64 ± 9.6 years, and 48 (86%) were female. Mean follow-up period was 2.6 ± 0.94 years. An excellent (mRS 0 to 1) outcome was archived in 31 (55%), 45 (82%), and 48 (87%) patients at 30 days, 6 months, and 12 months, respectively. Clinical and radiological characteristics showed no differences between two locations. One early death (1.8%) and one severe morbidity (1.8%) due to rupture were observed. The postoperative annual rupture rate was 1.4% overall (145 patient-years). After adjustment for age and location, large or giant DBA was related to 30-day and 12-month NW [n = 22 (39%) and n = 6 (11%); p = 0.009 and 0.002, respectively], aneurysm localization in the interpeduncular cistern (LIC) and perforator territory infarction were related to 30-day NW (p = 0.002 and 0.002), and DBA that needed bypass surgery and previously treated recurrent DBA were related to NW at 12 months (p = 0.017 and 0.001). Multivariate analysis showed that LIC was significantly related to perforator territory infarction (p = 0.003). Clinical and radiological characteristics were not different between basilar apex and BA-SCA aneurysms; therefore, they should not be discussed separately. To avoid neurological worsening, results of surgical treatment for unruptured DBAs should be improved.

Background It is essential to identify and be aware of the anatomy of the posterior condylar emissary vein (PCEV) for achieving an adequate operative field for the transcondylar fossa approach (TCFA). Objective To describe the variations in the drainage patterns of PCEVs and the technical issues encountered in such cases. Methods This was a retrospective analysis of the anatomy of PCEVs in 104 sides in 52 cases treated by the TCFA. Preoperative findings of multidetector-row computed tomography (CT) and CT venography (CTV) were compared with the intraoperative findings. The drainage patterns were classified as 5 types: the sigmoid sinus (SS), jugular bulb (JB), occipital sinus (OS), anterior condylar emissary vein (ACEV), and marginal sinus (MS). Results The SS, JB, ACEV, and OS types were observed in 33 (31.7%), 42 (40.3%), 8 (7.7%), and 1 (1.0%) side(s), respectively. One side (1.0%) each had combined drainage from MS and JB, and ACEV and JB, respectively. In 17 sides (16.3%), the PCEVs and posterior condylar canals could not be identified on CT and CTV. Conclusions Preoperative CT and CTV findings correlated well with the intraoperative findings. To make a sufficient operative field for TCFA, PCEVs should be appropriately dealt with based on the preoperative knowledge of their running course, pattern, and origin.

A 68-year-old woman presented with generalized seizure due to the left internal carotid artery (ICA) aneurysmal compression of the ipsilateral medial temporal lobe. Computed tomography angiography (CTA) revealed multiple aneurysms of the right persistent primitive hypoglossal artery (PPHA), the right ICA, and the right anterior cerebral artery (ACA). The right PPHA originated from the ICA at the level of the C1 and C2 vertebral bodies and passed through the hypoglossal canal (HC). The PPHA aneurysm was large and thrombosed, which was located at the bifurcation of the right PPHA and the right posterior inferior cerebellar artery (PICA), projecting medially to compress the medulla oblongata. Since this patient had no neurological deficits, sequential imaging studies were performed to follow this lesion, which showed gradual growth of the PPHA aneurysm with further compression of the brain stem. Although the patient remained neurologically intact, considering the growing tendency clipping of the aneurysm was performed. Drilling of the condylar fossa was necessary to expose the proximal portion of the PPHA inside the HC. The key of this surgery was the preoperative imaging studies to fully understand the anatomical structures. The PPHA was fully exposed from the dura to the corner its turning inferiorly without damaging the occipital condylar facet. Utilizing this technique, the neck ligation of the aneurysm was safely achieved without any surgical complications.

Background: Cardioembolic stroke is associated with a higher rate of functional limitation, which may be related to the larger ischemic lesion size. Endovascular therapy (EVT) for acute stroke caused by large vessel occlusion reduces severe disabilities. Objectives: We aimed to investigate the relationship between EVT and decompressive hemicraniectomy (DH) in patients with cardioembolic proximal intracranial occlusion in the anterior circulation (CPIOAC) using the data from the Recovery by Endovascular Salvage for Cerebral Ultra-acute Embolism (RESCUE)-Japan Registry 2. Methods: Among 2,420 patients in the RESCUE-Japan Registry 2, 555 patients aged 20–80 years with acute cardioembolic occlusion of the internal carotid artery and/or the first segment of the middle cerebral artery were included. The primary outcome was DH. Secondary outcomes were any type of intracranial hemorrhage, symptomatic intracranial hemorrhage indicating neurological worsening of >4 points on the National Institutes of Health Stroke Scale within 72 h after the onset of stroke, and recurrence of stroke or transient ischemic attack (TIA) within 90 days. Results: The median age was 73 years (66–77 years), and 360 patients (65%) were male. DH was performed in 1 of 374 patients in the EVT group and 5 of 181 patients in the no-EVT group (p = 0.032). The incidence of any type of intracranial hemorrhage and symptomatic intracranial hemorrhage within 72 h and recurrence of stroke or TIA within 90 days were similar between both groups. Conclusions: EVT may reduce DH in patients with CPIOAC without increasing intracranial hemorrhage.

Background The application of bypass procedures to the posterior cerebral artery (PCA) in combination with proximal clipping or trapping is a useful option for the treatment of complex posterior circulation aneurysms, especially those of the PCA. Because of its course around the midbrain through various cisterns, different approaches are required to access the PCA. Objective The presented study analyzes a retrospective case series of bypass procedures to the PCA to investigate the relevant treatment strategies and their outcomes. Methods Seven patients with bypass procedures to the PCA bypass were analyzed. The location of the aneurysms, approaches, site of anastomosis, bypass patency, pre- and postoperative modified Rankin Scale scores, and transient and permanent morbidity were assessed. Results Analyzed patients were treated for intracranial aneurysm located on the P2 ( n = 3) or P3 ( n = 2) of the PCA, bilateral vertebral artery dissecting aneurysm ( n = 1) or internal carotid artery-posterior communicating artery aneurysm ( n = 1). The following approaches were used: anterior temporal approach ( n = 2), anterior temporal approach combined with subtemporal approach ( n = 2), combined transpetrosal approach ( n = 1), posterior interhemispheric approach ( n = 1), and posterior interhemispheric approach with subtemporal approach ( n = 1). All bypasses were patent. Permanent morbidity occurred in 2 patients via cognitive dysfunction ( n = 1) and hemiparesis ( n = 1). Conclusions Bypass revascularization of the PCA territory is effective for the treatment of complex vascular lesions affecting the posterior circulation. To address the various surgical segments of the PCA, different approaches are required. Combined approaches allow access to the PCA proximal and distal from the lesion.

OBJECTIVE Bilateral vertebral artery dissecting aneurysms (VADAs) have a poor prognosis because progressive enlargement of the aneurysms compresses the brainstem or causes subarachnoid hemorrhage. The trapping of 1 vertebral artery (VA) places increased hemodynamic stress on the contralateral VA and may lead to enlargement and rupture. Therefore, management strategies are controversial. This study describes a radical treatment for bilateral VADAs using bypass surgery. METHODS Seven patients with bilateral VADAs were included. Three patients were treated by trapping of 1 VA via coiling or clipping at another hospital; the previously treated VA in 1 patient and the contralateral untreated VA in 2 patients subsequently enlarged. The other 4 patients presented without previous intervention and progressive enlargement of the aneurysms. RESULTS The post–coil embolization patients underwent V3–posterior cerebral artery (PCA) bypass and trapping. The other 4 patients underwent VA reconstruction via V3–V4 or V4–V4 bypass, with contralateral trapping on a separate day in 3 patients and observation in 1 patient. Perioperative complications included 1 case of cerebrospinal fluid leakage for which the patient required an additional operation, 1 case of dysphagia and facial palsy due to sigmoid sinus thrombosis, and 1 case of dysphagia. The long-term outcomes of these patients were favorable. CONCLUSIONS Patients with bilateral VADAs require treatment on both sides. If VA trapping is performed first, the treatment options for the other side are limited to V3-PCA bypass and trapping. This procedure is effective; however, it is also invasive and technically difficult. In cases of bilateral VADAs in which it is feasible to reconstruct 1 side, the best approach is to begin by reconstructing the VA that appears technically easiest, followed by trapping of the contralateral VADA. This strategy allows enough time to suture vessels because contralateral reverse flow is maintained.

OBJECT The revascularization technique, including bypass created using the external carotid artery (ECA), radial artery (RA), and M2 portion of middle cerebral artery (MCA), has remained indispensable for treatment of complex aneurysms. To date, it remains unknown whether diameters of the RA, superficial temporal artery (STA), and C2 portion of the internal carotid artery (ICA) and intraoperative MCA blood pressure have influences on the outcome and the symptomatic watershed infarction (WI). The aim of the present study was to evaluate the factors for the symptomatic WI and neurological worsening in patients treated by ECA-RA-M2 bypass for complex ICA aneurysm with therapeutic ICA occlusion. METHODS The authors measured the sizes of vessels (RA, C2, M2, and STA) and intraoperative MCA blood pressure (initial, after ICA occlusion, and after releasing the RA graft bypass) in 37 patients. Symptomatic WI was defined as presence of the following: postoperative new neurological deficits, WI on postoperative diffusion-weighted imaging, and ipsilateral cerebral blood flow reduction on SPECT. Neurological worsening was defined as the increase in 1 or more modified Rankin Scale scores. First, the authors performed receiver operating characteristic curve analysis for continuous variables and the binary end point of the symptomatic WI. The clinical, radiological, and physiological characteristics of patients with and without the symptomatic WI were compared using the log-rank test. Then, the authors compared the variables between patients with and without neurological worsening at discharge and at the 12-month follow-up examination or last hospital visit. RESULTS Symptomatic WI was observed in 2 (5.4%) patients. The mean MCA pressure after releasing the RA graft (< 55 mm Hg; p = 0.017), mean (MCA pressure after releasing the RA graft)/(initial MCA pressure) (< 0.70 mm Hg; p = 0.032), and mean cross-sectional area ratio ([RA/C2 diameter]2 < 0.40 mm [p < 0.0001] and [STA/C2 diameter]2 < 0.044 mm [p < 0.0001]) were related to the symptomatic WI. All preoperatively independent patients remained independent (modified Rankin Scale score < 3). After adjusting for age and sex, left operative side (p = 0.0090 and 0.038) and perforating artery ischemia (p = 0.0050 and 0.022) were related to neurological worsening at discharge (11 [29%] patients) and at the 12-month follow-up or last hospital visit (8 [22%] patients). CONCLUSIONS Results of the present study showed that the vessel diameter and intraoperative MCA pressure had impacts on the symptomatic WI and that operative side and perforating artery ischemia were related to neurological worsening in patients with complex ICA aneurysms treated by ECA-RA-M2 bypass.

A craniotomy that passes through the frontal air sinus (FAS) often results in postoperative complications such as infection, cerebrospinal fluid leakage or mucocele formation. A good understanding of FAS reconstruction can decrease the morbidity rate of complications. This study describes the outcomes of treatment and establishes the most effective technique for FAS reconstruction in our institution. We enrolled 107 patients who had a bifrontal craniotomy which exposed the FAS during the operation for an anterior communicating artery (ACoA) aneurysm. Demographic data including the follow-up information were collected and analyzed. The complications after surgery were observed and described in the treatment procedure. The patency of the nasofrontal outflow tract (NFOT) was proved by removal of blood clots and bone dust by irrigation and by direct inspection under a microscope before closure of the frontal sinus mucosa with a monofilament non-absorbable 7/0 material suture. The dura was closed in a watertight fashion and an abdominal fat graft was packed into the FAS cavity. There were 33 male and 74 female patients and the mean age (range) was 64 years (32–90 years). The mean follow-up time was 13 months (1–35 months) and complications were found in only 2 patients. One patient suffered from dislocation of the fat graft and the other patient developed a surgical wound infection. At post-operation the first patient sneezed several times and the second patient suffered from trauma in the nasal area after discharge to home. Both patients were surgically treated and cured. In conclusion, FAS reconstruction from our technique is very effective for the prevention of complications after bifrontal craniotomy. Direct suturing of the frontal sinus mucosa and proving the patency of the NFOT are keys to successful treatment.

Objective Extracranial to intracranial (EC-IC) high-flow bypass using radial artery or saphenous vein (SV) graft has remained vital for complex aneurysms. If an Allen test is positive, the radial artery cannot be harvested because of poor palmer collateral circulation. The valves are thought to be one of causes of SV graft failure. Herein we illustrate the “valveless SV graft technique” as bypass conduits. Methods Between August 2014 and December 2014 at the Department of Neurosurgery at Teishinkai Hospital, 4 patients whose Allen test was positive underwent EC-IC bypass with the valveless SV graft for complex internal carotid artery (ICA) aneurysm. After SV harvesting, we identified the SV valve, cut it, and performed an end-to-end anastomosis using the fish mouth trimming technique. Graft patency was confirmed by computed tomography angiography. Results We have not encountered any problems related to graft failure, and all valveless SV grafts were patent during the follow-up period (median, 210 days; interquartile range, 93–287 days). Conclusions The valveless SV graft technique is a useful technique in patients with complex ICA aneurysms who undergo EC-IC high-flow bypass with therapeutic ICA occlusion and whose Allen tests are positive.

Objective Giant, or complex, aneurysms of the anterior cerebral artery (ACA) are rare, but their surgical treatment is important. The authors describe their experiences with bypasses for complex ACA aneurysms and discuss the new classification of ACA bypasses, the concept of using bypasses for insurance during the approach to the aneurysm, and simplifying the surgical algorithms for these complex ACA aneurysms. Methods Over a 19-year period, 7 cases of complex ACA aneurysm were treated with bypasses and reviewed retrospectively. The bypasses were classified into 4 groups according to donor blood flow: internal carotid artery-ACA, external carotid artery-ACA, communicating bypass, and reconstruction bypass of the ipsilateral postcommunicating ACA. Results The cases included 1 precommunicating aneurysm, 3 communicating aneurysms, 2 postcommunicating aneurysms, and 1 double aneurysm (communicating and postcommunicating). The types of bypass included 1 internal carotid artery-ACA, 6 communicating bypasses, 3 external carotid artery-ACAs, and 2 reconstruction bypass of the postcommunicating ACA. Postoperative modified Rankin Scale scores were 0 (6 cases) and 3 (1 case of a communicating aneurysm with complicated memory disturbance because of infarction). One case revealed asymptomatic infarction. Conclusions Surgical treatment of complex ACA aneurysms requires knowledge of a variety of bypass techniques. Although the type of bypass should be selected according to patient-specific anatomy and the neurosurgeon's preference, the new classification of bypass-specified ACA aneurysms may alter the way surgeons think about ACA bypasses, and in combination with the concept of the protective bypass, can be used to establish a comprehensive algorithm for each type of complex ACA aneurysm.

Basilar dolichoectasia (BD) is an atherosclerotic, a distinct arteriopathy or a chronic-phase dissection characterized by elongation and dilation of the basilar artery. Spontaneous intradural vertebral artery dissection (siVAD) is an important cause of stroke in young and middle-aged people. It is hypothesized that the BD and the siVAD might partially share aetiologies and this study aimed to examine the relationship.This study compared clinical and radiological characteristics in 93 patients with siVAD with 93 controls. Ectasia was defined as basilar artery diameter4.5 mm and dolichosis, as either basilar artery bifurcation above the suprasellar cistern or lateral to the margin of the clivus or dorsum sellae. The BD was defined if both ectasia and dolichosis were simultaneously observed. Multivariate logistic regression analysis was performed using variables that were marginally or significantly associated with siVAD on univariate analysis (p 0.20).Multivariate analysis showed siVAD patients have higher proportions of hypertension (OR = 2.4; 95% CI = 1.3-4.6; p = 0.007) and BD (OR = 3.7; 95% CI = 1.1-12; p = 0.036).The present study suggested that BD was related to the siVAD. A randomized study from multi-institutions with an adequate sample size is needed to make a strong argument about the association between BD and siVAD.

Background Regardless of acceptable surgical results of middle cerebral artery aneurysms (MCAs), MCA territory infarction (MCATI) remains a major obstacle to achieving a good outcome. We investigated the MCATI in patients with surgically treated MCA aneurysms. Methods The data of 286 consecutive patients with 322 MCA aneurysms were evaluated retrospectively. The aneurysm location was classified as early frontal cortical branch (EFCB), early temporal cortical branch (ETCB), bifurcation or trifurcation (M1-2), and distal aneurysms on the insular, opercular, or cortical segments of the MCA (distal MCA). Neurologic worsening was defined as an increase in 1 or more modified Rankin Scale (mRS) scores. Results Multivariate analysis identified EFCB location as the sole risk factor for MCATI (odds ratio [OR], 3.8; 95% confidence interval [CI], 1.2–12; P = 0.021) and MCATI (OR, 18; 95% CI, 2.8–117; P = 0.002) and a larger size ratio (OR, 1.4; 95% CI, 1.1–1.8; P = 0.019) were related to 12-month neurologic worsening (n = 6; 1.9%). During follow-up (median, 885 days; interquartile range, 485–1229 days), posttreatment rupture and aneurysm recurrence were not observed. Conclusions In the present study, compared with M1-2 aneurysms, MCATIs were observed more frequently in EFCB aneurysms, and the presence of MCATI and a larger size ratio were related to 12-month neurologic worsening in patients with surgically treated MCA aneurysms.

Surgical or endovascular treatment for giant or complex aneurysms is challenging. The aims of this study were to evaluate clinical outcomes and factors affecting the prognosis of giant or complex aneurysms and to better establish the role of microsurgery in the management strategy.One hundred fifty-nine patients with surgically treated complex aneurysms were included. Thirty-two patients (20.1%) had giant aneurysms (≥25 mm) and 57 (35.8%) had large aneurysms (≥15 mm). Poor outcome was defined as modified Rankin Scale scores of 3-6.The mean aneurysm size was 17.0 mm (range, 1.6-47.5 mm). One hundred and sixteen aneurysms (80.0%) were in the anterior circulation and 43 (27.0%) were in the posterior circulation. One hundred and thirty-eight (86.8%) aneurysms were completely occluded without residual aneurysms. Nineteen (11.9%) had minor aneurysm remnants; 2 (1.3%) had incomplete occlusion. Two patients (1.3%) with giant basilar artery (BA) trunk aneurysms experienced rupture of the treated aneurysm and died. Bypass surgery was combined with microsurgery in 148 patients (93.1%). Perforating artery infarction was observed postoperatively in 42 patients (26.4%), and poor outcome was observed in 29 (18.2%). Male sex (P = 0.016; adjusted odds ratio [OR], 4.524 [1.949-10.500]), perforating artery infarction (P0.001; adjusted OR, 13.625 [5.329-34.837]), and BA aneurysm location (P = 0.003; adjusted OR, 56.333 [6.830-464.657]) were significantly related to poor outcome. The aneurysm size (P = 0.017; adjusted OR, 1.064 [1.021-1.107]), C1 aneurysm location (P = 0.042; adjusted OR, 2.591 [0.986-6.811]), and BA aneurysm location (P = 0.033; adjusted OR, 12.956 [3.197-52.505]) were significantly related to perforating artery infarction.Microsurgery with bypass is effective for many different complex aneurysms, except BA aneurysms.

The risk associated with surgical treatment for small-to-moderate size unruptured intracranial aneurysms (SMUIAs, defined as15 mm) has not been well characterized. Authors aimed to investigate risk factors for poor outcome in surgical treatment of SMUIAs. The data of prospectively collected 801 consecutive patients harboring 971 surgically treated SMUIAs was evaluated. Neurological worsening (NW) was defined as an increase in 1 or more modified Rankin Scale at 12-month. Clinical and radiological characteristics were compared. Neurological worsening was observed in 45 (4.6%). In multivariate analysis, only perforator territory infarction (PTI) on postoperative diffusion-weighted imaging (odds ratio (OR), 13; 95% confidence interval (CI), 4.9-32, p 0.0001), and aneurysm locations (paraclinoid (OR, 6.9; 95% CI, 3.1-15, p 0.0001), basilar artery (OR, 4.5; 95% CI, 1.5-14, p = 0.008), vertebral artery (OR, 11; 95% CI, 3.3-34, p 0.0001)) were related to neurological worsening. Multivariate analysis showed that statin use (OR, 12; 95% CI, 3.8-39, p 0.0001) and aneurysm locations (internal carotid artery-posterior communicating artery (OR, 3.9; 95% CI, 1.8-8.2, p 0.0001) and basilar artery (OR, 6.3; 95% CI, 2.3-17, p = 0.008)), and aneurysm size10 mm (OR, 5.3; 95% CI, 1.8-15, p = 0.003) were related to PTI. Although all SMUIAs should be carefully considered whether to be treated, those with statins, specific locations, and larger sizes should perhaps be more meticulously contemplated, and neurosurgeons should continue to avoid PTI.

The pathogenesis of basilar apex aneurysm (BAA) are still poorly understood. Embryologically, basilar apex anatomical disposition is formed by the fusion of both caudal internal carotid divisions on the midline. To compare basilar apex morphology by embryological classification among patients with BAAs, anterior circulation aneurysms (ACAs), and controls. Prospectively collected data of 47 consecutive patients with unruptured BAAs (42 females and five males), age- and gender-matched 47 patients with unruptured ACAs, and 47 controls without any aneurysms were analyzed. Based on embryology, basilar apex morphology was classified into symmetric cranial fusion (SCrF), symmetric caudal fusion, and asymmetric fusion type. Posterior communicating artery (Pcom) was classified into hypoplastic, adult, or fetal type. The asymmetrical Pcom was defined as bilaterally different type Pcom. The ACAs located at the anterior communicating artery (n = 18), paraclinoid portion (n = 12), middle cerebral artery (n = 8), anterior cerebral artery (n = 5), the top of internal carotid artery (n = 2), and anterior choroidal artery (n = 2). Compared with the ACA group and controls, smoking, asymmetrical Pcom (fetal and adult type), and SCrF type were more prevalent in patients with BAAs by residual analysis. The multinomial logistic regression comparative analysis demonstrated that SCrF type was associated with BAAs (vs. ACA group; odds ratio, 13; 95% confidence interval, 3.8–41 and vs. controls; odds ratio, 25; 95% confidence interval, 5.4–121). The assessment of basilar apex morphology may aid in the understanding of the pathogenesis of BAA and the prediction of BAA formation.

This study investigated whether the size of the middle cranial fossa foramina reflects the severity of moyamoya disease (MMD).It compared 20 adult patients managed without surgical revascularization with 2 age- and sex-matched controls. MR angiography scores were assigned by the severity of occlusive changes of the internal carotid artery, the middle cerebral artery, the anterior and the posterior cerebral arteries and the signals of the distal branches of these arteries. These scores were stratified into MR angiography grades (Houkin's grade: 1-4). The relationships between the Houkin's grade and the size of the foramen spinosum (FS), foramen ovale, carotid canal and middle meningeal artery (MMA) were evaluated.Simple regression analysis showed the correlation between the Houkin's grade and the bilateral FS (right, r = 0.56, p = 0.010; left, r = 0.46, p = 0.044) and MMA (right, r = 0.89, p = 0.0050; left, r = 0.47, p = 0.036). It also showed the correlation between the FS and MMA (right, r = 0.53, p = 0.018; left, r = 0.55, p = 0.013). There were no significant differences between the Houkin's grade, the size of the carotid canal and the foramen ovale.The larger FS and MMA on brain CT, which might be performed for patients suspected of intracranial lesions, could aid the diagnosis of MMD.

OBJECTIVEIt is well known that larger aneurysm size is a risk factor for poor outcome after surgical treatment of unruptured saccular intracranial aneurysms (USIAs). However, the authors have occasionally observed poor outcome in the surgical treatment of small USIAs and hypothesized that size ratio has a negative impact on outcome. The aim of this paper was to investigate the influence of size ratio on outcome in the surgical treatment of USIAs.METHODSProspectively collected clinical and radiological data of 683 consecutive patients harboring 683 surgically treated USIAs were evaluated. Dome-to-neck ratio was defined as the ratio of the maximum width of the aneurysm to the average neck diameter. The aspect ratio was defined as the ratio of the maximum perpendicular height of the aneurysm to the average neck diameter of the aneurysm. The size ratio was calculated by dividing the maximum aneurysm diameter (height or width, mm) by the average parent artery diameter (mm). Neurological worsening was defined as an increase in modified Rankin Scale score of 1 or more points at 12 months. Clinical and radiological variables were compared between patients with and without neurological worsening.RESULTSThe median patient age was 64 years (IQR 56–71 years), and 528 (77%) patients were female. The median maximum size, dome-to-neck ratio, aspect ratio, and size ratio were 4.7 mm (IQR 3.6–6.7 mm), 1.2 (IQR 1.0–1.4), 1.0 (IQR 0.76–1.3), and 1.9 (IQR 1.4–2.8), respectively. The size ratio was significantly correlated with maximum size (r = 0.83, p < 0.0001), dome-to-neck ratio (r = 0.69, p < 0.0001), and aspect ratio (r = 0.74, p < 0.0001). Multivariate logistic regression analysis showed that the specific USIA location (paraclinoid segment of the internal carotid artery: OR 6.2, 95% CI 2.6–15, p < 0.0001; and basilar artery: OR 8.4, 95% CI 2.8–25, p < 0.0001), size ratio (OR 1.3, 95% CI 1.1–1.6, p = 0.021), and postoperative ischemic lesion (OR 9.4, 95% CI 4.4–19, p < 0.0001) were associated with neurological worsening (n = 52, 7.6%), and other characteristics showed no significant differences.CONCLUSIONSThe present study showed that size ratio, and not other morphological parameters, was a risk factor for 12-month neurological worsening in surgically treated patients with USIAs. The size ratio should be further studied in a large, prospective observational cohort to predict neurological worsening in the surgical treatment of USIAs.

OBJECTIVEOnly a few previous studies have investigated subarachnoid hemorrhage (SAH) after surgical treatment in patients with unruptured intracranial aneurysms (UIAs). Given the improvement in long-term outcomes of embolization, more extensive data are needed concerning the true rupture rates after microsurgery in order to provide reliable information for treatment decisions. The purpose of this study was to investigate the incidence of and risk factors for postoperative SAH in patients with surgically treated UIAs.METHODSData from 702 consecutive patients harboring 852 surgically treated UIAs were evaluated. Surgical treatments included neck clipping (complete or incomplete), coating/wrapping, trapping, proximal occlusion, and bypass surgery. Clippable UIAs were defined as UIAs treated by complete neck clipping. The annual incidence of postoperative SAH and risk factors for SAH were studied using Kaplan-Meier survival analysis and Cox proportional hazards regression models.RESULTSThe patients’ median age was 64 years (interquartile range [IQR] 56–71 years). Of 852 UIAs, 767 were clippable and 85 were not. The mean duration of follow-up was 731 days (SD 380 days). During 1708 aneurysm years, there were 4 episodes of SAH, giving an overall average annual incidence rate of 0.23% (95% CI 0.12%–0.59%) and an average annual incidence rate of 0.065% (95% CI 0.0017%–0.37%) for clippable UIAs (1 episode of SAH, 1552 aneurysm-years). Basilar artery location (adjusted hazard ratio [HR] 23, 95% CI 2.0–255, p = 0.0012) and unclippable UIA status (adjusted HR 15, 95% CI 1.1–215, p = 0.046) were significantly related to postoperative SAH. An excellent outcome (modified Rankin Scale score of 0 or 1) was achieved in 816 (95.7%) of 852 cases overall and in 748 (98%) of 767 clippable UIAs at 12 months.CONCLUSIONSIn this large case series, microsurgical treatment of UIAs was found to be safe and effective. Aneurysm location and unclippable morphologies were related to postoperative SAH in patients with surgically treated UIAs.

Background Anterior cerebral artery aneurysms (ACAs) are characterized by higher rupture rate and small size at rupture. It was shown that the aneurysm/vessel size ratio, and not the absolute size, might predict the risk of rupture in small unruptured intracranial aneurysms. The present study aimed to investigate the relationship between a size ratio and outcome in patients with unruptured nondissecting ACA aneurysms (UNDAs). Methods A total of 187 consecutive patients with 12 A1 (6.2%), 149 anterior communicating artery (77%), and 33 distal ACA (17%) aneurysms were retrospectively evaluated. The size ratio was defined as (size of aneurysm)/(size of parent artery). Neurologic worsening (NW) was defined as an increase in score of 1 or more on the modified Rankin Scale (mRS). Results The mean age of the patient population was 63 ± 11 years and 132 UNDAs (68%) were seen in women. Complete, partial neck clipping, and aneurysm trapping were archived in 188 (97%), 2 (1.0%), and 4 (2.1%) UNDAs, respectively. An excellent outcome (mRS score 0) at 12 months was archived in 177 (93%) UNDAs overall and 177 (95%) in UNDAs with preoperative mRS score of 0 (n = 186). Postoperative ischemic lesions (odds ratio, 193; 95% confidence interval, 17–2205; P 3.0 (odds ratio, 11; 95% confidence interval, 1.2–105; P = 0.031) were related to 12-month NW on multivariate analysis. The aneurysm size was not related to 12-month NW. Conclusions The present study showed that the size ratio, and not the absolute size, was related to 12-month NW in surgically treated UNDAs.

OBJECTIVEAfter internal carotid artery (ICA) sacrifice without revascularization for complex aneurysms, ischemic complications can occur. In addition, hemodynamic alterations in the circle of Willis create conditions conducive to the formation of de novo aneurysms or the enlargement of existing untreated aneurysms. Therefore, the revascularization technique remains indispensable. Because vessel sizes and the development of collateral circulation are different in each patient, the ideal graft size to prevent low flow–related ischemic complications (LRICs) in external carotid artery (ECA)–middle cerebral artery (MCA) bypass with therapeutic ICA occlusion (ICAO) has not been well established. Authors of this study hypothesized that the adequate graft size could be calculated from the size of the sacrificed ICA and the values of MCA pressure (MCAP) and undertook an investigation in patients with complex ICA aneurysms treated with ECA-graft-MCA bypass and therapeutic ICAO.METHODSIn the period between July 2006 and January 2016, 80 patients with complex ICA aneurysms were treated with ECA-MCA bypass and therapeutic ICAO. Preoperative balloon test occlusion (BTO) was performed, and the BTO pressure ratio was defined as the mean stump pressure/mean preocclusion pressure. Low flow–related ischemic complications were defined as new postoperative neurological deficits and ipsilateral cerebral blood flow reduction. Initial MCAP (iMCAP), MCAP after clamping the ICA (cMCAP), and MCAP after releasing the graft (gMCAP) were intraoperatively monitored. The MCAP ratio was defined as gMCAP/iMCAP. Based on the Hagen-Poiseuille law, the expected MCAP ratio ([expected gMCAP]/iMCAP) was hypothesized as follows: (1 – cMCAP/iMCAP)(graft radius/ICA radius)2 + (cMCAP/iMCAP). Correlations between the BTO pressure ratio and cMCAP/iMCAP, and between the actual and expected MCAP ratios, were evaluated. Risk factors for LRICs were also evaluated.RESULTSThe mean BTO pressure ratio was significantly correlated with the mean cMCAP/iMCAP (r = 0.68, p < 0.0001). The actual MCAP ratio correlated with the expected MCAP ratio (r = 0.43, p < 0.0001). If the expected MCAP ratio was set up using the BTO pressure ratio instead of cMCAP/iMCAP (BTO-expected MCAP ratio), the mean BTO-expected MCAP ratio significantly correlated with the expected MCAP ratio (r = 0.95, p < 0.0001). During a median follow-up period of 26.1 months, LRICs were observed in 9 patients (11%). An actual MCAP ratio < 0.80 (p = 0.003), expected MCAP ratio < 0.80 (p = 0.001), and (M2 radius/graft radius)2 < 0.49 (p = 0.002) were related to LRICs according to the Cox proportional-hazards model.CONCLUSIONSData in the present study indicated that it was important to use an adequate graft to achieve a sufficient MCAP ratio in order to avoid LRICs and that the adequate graft size could be evaluated based on a formula in patients with complex ICA aneurysms treated with ICAO.

Objectives For patients with non-traumatic pontine hemorrhage (PH) who will survive, determining prognosis is vital for appropriate therapeutic planning in the acute stage. This study aimed to determine reliable prognostic factors of mortality in patients with PH. Materials and methods The cases of a total of 118 consecutive PH patients were reviewed. We compared clinical and radiological characteristics between patients who died and survivors by the log-rank test and performed multivariate analysis by the Cox proportional hazards model using variables that were marginally or significantly associated with PH-related death on the log-rank test (P

Object Recent studies have shown that posterior circulation aneurysms, specifically posterior communicating artery (PCoA) aneurysms, are more likely to rupture than other aneurysms. To date, few studies have investigated the factors contributing to PCoA aneurysm rupture. The authors aimed to identify morphological and clinical characteristics predisposing to PCoA aneurysm rupture. Methods The authors retrospectively reviewed 134 consecutive patients with PCoA aneurysms managed at their facility between July 2003 and December 2012. The authors divided patients into groups of those with aneurysmal rupture (n = 39) and without aneurysmal rupture (n = 95) and compared morphological and clinical characteristics. Morphological characteristics were mainly evaluated by 3D CT angiography and included diameter of arteries (anterior cerebral artery, middle cerebral artery, and internal carotid artery), size of the aneurysm, dome-to-neck ratio, neck direction of the aneurysmal dome around the PCoA (medial, lateral, superior, inferior, and posterior), aneurysm bleb formation, whether the PCoA was fetal type, and the existence of other intracranial unruptured aneurysm(s). Results Patients with ruptured PCoA aneurysms were significantly younger (a higher proportion were < 60 years of age) and a significantly higher proportion of patients with ruptured PCoA aneurysms showed a lateral direction of the aneurysmal dome around the PCoA, had bleb formation, and the aneurysm was > 7 mm in diameter and/or the dome-to-neck ratio was > 2.0. Multivariate logistic regression analysis showed age < 60 years (OR 4.3, p = 0.011), history of hypertension (OR 5.1, p = 0.008), lateral direction of the aneurysmal dome around the PCoA (OR 6.7, p = 0.0001), and bleb formation (OR 11, p < 0.0001) to be significantly associated with PCoA aneurysm rupture. Conclusions The present results demonstrated that lateral projection of a PCoA aneurysm may be related to rupture.