A comparison of Atlas and Leo Baby stents-assisted coiling of intracranial aneurysms with small parent vessels.

Some studies have reported the efficacy and safety of the Atlas stent and the Leo Baby stent-assisted coiling (SAC) of intracranial aneurysms arising from small cerebral vessels. The authors aimed to compare the clinical performance of the Atlas and the Leo Baby stents in small parent arteries. Methods and materials: Between January 2019 and November 2022, 56 patients at our centre were treated using either Atlas or Leo Baby SAC of intracranial aneurysms arising from small parent vessels (<2 mm). The clinical and angiographic imaging data of the two cohorts were retrospectively collected and comparatively analyzed. Results: A total of 56 patients were included in this study. Thirty-two patients were treated with the Atlas SAC, and 24 patients were treated with the Leo Baby SAC. The mean age of the Atlas stent cohort was older, and the mean aneurysm size was smaller than the Leo Baby stent. The immediate complete occlusion rate was 68.6% in the Atlas stent cohort and 62.5% in the Leo Baby stent cohort. The mean angiographic follow-up time for Atlas stent cohort was 8.9±2.5 months, and the final aneurysm complete occlusion rate was 81.0%. The mean follow-up time for Leo Baby stent cohort was 18.9±6.0 months, and the final aneurysm complete occlusion rate was 83.3%. Conclusions: At the final follow-up, the Atlas or the Leo baby stent SAC of intracranial aneurysms with small parent vessels resulted in favourable angiographic results and clinical outcomes, with a low rate of associated complications.

Adjuvant Corticosteroids With Surgery for Chronic Subdural Hematoma: A Systematic Review and Meta-Analysis.

The use of adjuvant corticosteroids with surgery for chronic subdural hematoma (CSDH) has received considerable attention in recent years. However, there is no conclusive evidence regarding its effectiveness and safety for CSDH. Therefore, we performed a meta-analysis and systematic review to evaluate the effectiveness and safety of corticosteroids as an adjuvant treatment for the treatment of CSDH. We comprehensively searched electronic databases (PubMed, EMBASE, Cochrane Library, and Web of Science) to identify relevant trials that investigated the efficacy and safety of adjuvant corticosteroids with surgery for CSDH, published from inception until May 2021. Outcome measures included recurrence rate, all-cause mortality, good functional outcome, length of hospitalization, and adverse events. We used the Cochrane risk of bias method to evaluate the quality of randomized controlled trials (RCTs), and the Newcastle Ottawa Scale to evaluate the quality of observational studies. We included nine studies, consisting of three RCTs and six observational studies, that compared corticosteroids as an adjuvant treatment to surgery with surgery alone. Pooled results revealed that the risk of recurrence was significantly reduced in patients who received adjuvant corticosteroids with surgery compared to those who underwent surgery alone (relative risk [RR] = 0.52, 95% confidence interval [CI] = 0.39-0.69, p < 0.00001). However, no statistically significant difference was observed between these groups in all-cause mortality (RR = 0.91, 95% CI = 0.37-2.23, p = 0.83), good functional outcome (RR = 1.03, 95% CI = 0.96-1.10, p = 0.47), length of hospitalization (MD = 0.35, 95% CI = -2.23 to 1.67, p = 0.83), and infection rates (RR = 0.99, 95% CI = 0.64-1.53, p = 0.95). Adjuvant corticosteroids with surgery reduce the risk of recurrence of CDSH, but do not improve the all-cause mortality or functional outcome, as compared to surgery alone. These findings support the use of adjuvant corticosteroids with surgery for CSDH patients. Further high-quality RCTs are required to confirm the efficacy and safety of adjuvant corticosteroids in the treatment of CSDH patients.

The Prognostic Value of Neutrophil-to-Lymphocyte Ratio in Patients With Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis of Observational Studies.

The neutrophil-to-lymphocyte ratio (NLR), as an essential systemic inflammation factor, has been widely used as a prognostic indicator in various diseases, such as malignant tumors, cardiovascular disease, and intracranial hemorrhage. An increasing number of studies have believed that NLR is a valuable predictor of prognosis for patients with aneurysmal subarachnoid hemorrhage (aSAH). However, these results remain controversial. In the current study, we planned to carry out a systematic review and meta-analysis to investigate the association between NLR and poor outcome, and the occurrence of delayed cerebral ischemia (DCI). We carried out a comprehensive search for published literatures on PubMed, EMBASE, Cochrane Library, and Web of Science databases from inception to April 1, 2021. We conducted an assessment of all included studies based on the principles proposed in the Newcastle-Ottawa Quality Assessment Scale (NOS). Poor outcome and the occurrence of DCI were considered as the main outcome measure. We calculated the pooled odds ratio (OR) and corresponding 95% confidence interval (CI) to examine the strength of the association of NLR with poor outcome or the occurrence of DCI. We strictly selected a total of 10 studies comprising 4,989 patients. Nine studies reported the association between NLR and poor outcome, and five studies reported the association between NLR and the occurrence of DCI. The pooled results indicated higher NLR was significantly associated with both poorer outcomes (OR = 1.32, 95%CI 1.11-1.57; P = 0.002, I 2 = 87%), and the occurrence of DCI (OR = 1.72, 95%CI 1.22-2.41; P = 0.002, I 2 = 82%) in aSAH patients. The NLR is a valuable indicator of inflammation to independently predict poor outcome and occurrence of DCI after aSAH, where a higher NLR is significantly associated with poor outcomes and occurrence of DCI. These findings suggest that the NLR can help clinicians evaluate the prognosis and identify potentially severe patients early, which may contribute to better management and improve poor prognosis of aSAH patients.

Combined Endovascular and Surgical Treatment for Brain Arteriovenous Malformations in Biplanar Hybrid Operating Room.

OBJECTIVE: Combined surgical and endovascular treatment for vascular disorders has become prevalent in recent years. However, reports on one-session hybrid surgery for arteriovenous malformations (AVMs) are relatively rare. The safety and efficiency of combined treatment for brain AVMs were analyzed in biplanar hybrid operating room (OR) at one stage. METHODS: We retrospectively analyzed 20 patients with AVMs undergoing combined surgical and endovascular treatment from October 2015 to June 2018. The data for resection rate, microcatheter adhesion, surgical position and postoperative outcomes were analyzed. Total resection or near-total resection was achieved in all cases. RESULTS: A total of 13 patients were under combined endovascular and surgical procedures, and 7 experienced surgery with intraoperative digital subtraction angiography. Sitting position was applied in 3 of them; 2 niduses in cerebellum, and 1 in parietal lobe. Compared with admission modified Rankin Scale (mRS) in all patients, postoperative 12-month mRS showed a significant decline. Besides, 3 patients experienced microcatheter adhesion after endovascular embolization, thereafter underwent surgical adhesion removal while nidus resection was done. CONCLUSION: Combined endovascular and surgical modality in a hybrid OR at one stage provides a safe strategy for the treatment of AVMs. The biplanar hybrid neurointerventional suite is endowed with unconstrained operating angle which enables combined endovascular and surgical treatment in sitting position. It also reduces the risk of microcatheter adhesion, which enables interventional radiologists to perform aggressively.

Efficacy and Safety of Tranexamic Acid in Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Tranexamic acid has been shown to reduce rebleeding after aneurysmal subarachnoid hemorrhage; however, whether it can reduce mortality and improve clinical outcomes is controversial. We performed a systematic review and meta-analysis to evaluate the efficacy and safety of the tranexamic acid in aneurysmal subarachnoid hemorrhage. We conducted a comprehensive literature search of PubMed, Embase, Web of Science, and Cochrane Library from inception to March 2021 for randomized controlled trials (RCTs) comparing tranexamic acid and placebo in adults with aneurysmal subarachnoid hemorrhage. The risk of bias was evaluated using the Cochrane Handbook, and the quality of evidence was evaluated using the GRADE approach. This meta-analysis included 13 RCTs, involving 2,888 patients. In patients with aneurysmal subarachnoid hemorrhage tranexamic acid had no significant effect on all-cause mortality (RR = 0.96; 95% CI = 0.84-1.10, p = 0.55, I 2 = 44%) or poor functional outcome (RR = 1.04; 95% CI = 0.95-1.15, p = 0.41) compared with the control group. However, risk of rebleeding was significantly lower (RR = 0.59; 95% CI = 0.43-0.80, p = 0.0007, I 2 = 53%). There were no significant differences in other adverse events between tranexamic acid and control treatments, including cerebral ischemia (RR = 1.17; 95% CI = 0.95-1.46, p = 0.15, I 2 = 53%). At present, routine use of tranexamic acid after subarachnoid hemorrhage cannot be recommended. For a patient with subarachnoid hemorrhage, it is essential to obliterate the aneurysm as early as possible. Additional higher-quality studies are needed to further assess the effect of tranexamic acid on patients with subarachnoid hemorrhage.

Single-stage endovascular treatment of subarachnoid hemorrhage related to bilateral vertebral artery dissecting aneurysms.

OBJECTIVE: Treatment of bilateral vertebral artery dissecting aneurysms presenting with subarachnoid hemorrhage remains challenging as bilateral deconstructive procedures may not be feasible. In this case series, we describe our approach to their management and review the pertinent literature. METHOD: A retrospective review of our prospectively collected database on aneurysms was performed to identify all patients with acute subarachnoid hemorrhage in the setting of bilateral intradural vertebral artery dissections (VAD) encompassing a period from January 2000 and March 2012. RESULT: Four patients (M/F = 2/2; mean age, 51.5 years) were identified. In two cases the site of rupture could be identified by angiographic and cross-sectional features; in these patients deconstructive treatment (proximal obliteration or trapping) of the ruptured site and reconstructive treatment of the unruptured site (using stents and coils) were performed. In the patients in whom the site of hemorrhage could not be determined, bilateral reconstructive treatment was performed. No treatment-related complications were encountered. Modified Rankin scale scores were 0-1 at discharge, and on follow-up (mean 63 months), no recurrence, in-stent thrombosis or new neurological deficits were encountered. CONCLUSION: We believe that single-stage treatment in patients with bilateral VAD is indicated: If the site of hemorrhage can be determined, we prefer deconstructive treatment on the affected site and reconstructive treatment on the non-affected site to prevent increased hemodynamic stress on the unruptured but diseased wall. If the site of dissection cannot be determined, we prefer bilateral reconstructive treatment to avoid increasing hemodynamic stress on the potentially untreated acute hemorrhagic dissection.

Using DynaCT rotational angiography for angioarchitecture evaluation and complication detection in spinal vascular diseases.

OBJECTIVE: Preoperative comprehension of the complex angioarchitecture and intraoperative complication detection are essential in endovascular treatment and surgical planning for spinal vascular diseases. We aimed to illustrate the application of DynaCT rotational angiography for the treatment of such diseases. METHODS: We retrospectively analyzed the medical records of 23 patients with spinal vascular disease who underwent DynaCT and three-dimensional (3D) rotational angiography between January 2012 and December 2013. Diseases included spinal arteriovenous malformation, spinal dural arteriovenous fistula, and hypervascular neoplasm. Radiological post-processing images and procedural complications were reviewed to compare the advantage of rotational angiography and digital subtraction angiography (DSA). RESULTS: Rotational angiography more clearly revealed the complex angioarchitecture in cases of spinal vascular diseases based on coronal, sagittal, and transverse views compared with DSA. Subarachnoid hemorrhage was confirmed with DynaCT in one patient with spinal arteriovenous malformation, which was not shown on DSA. Both two-dimensional and 3D angiograms effectively identified the fistulous points in five cases of spinal dural arteriovenous fistula while rotational angiography vividly demonstrated the relationship of the fistulous point with the osseous structures in dual-volume mode. Tumor feeders were clearly delineated in 3D reconstructed images and easily cauterized in patients with hemangioblastoma. CONCLUSIONS: Rotational angiography clarified the relationship between the vasculature and surrounding osseous structures for surgical or endovascular therapy of spinal vascular diseases. DynaCT can detect intraoperative subarachnoid hemorrhage in a timely manner during endovascular treatment of spinal vascular diseases.

Parent artery reconstruction for large or giant cerebral aneurysms using a Tubridge flow diverter (PARAT): study protocol for a multicenter, randomized, controlled clinical trial.

BACKGROUND: The treatment of large (10-25 mm) or giant (≥25 mm) cerebral aneurysms remains technically challenging, with a much higher complication and recanalization rate than that is observed for smaller aneurysms. The use of a flow diverter seems to facilitate the treatment of this special entity. In a previous single-center prospective study approved by the Ethics Committee and China Food and Drug Administration (CFDA), we obtained promising results, showing remarkable safety and effectiveness for the Tubridge flow diverter. Nevertheless, the previous study may have been limited by biases due to its single-center design and limited number of subjects. Furthermore, although various articles have reported durable results from treating aneurysms using flow diverters, increasing questions have arisen about this form of treatment. Thus, prospective, multiple-center, randomized trials containing more subjects are needed. METHODS/DESIGN: This study is a multicenter, randomized, controlled clinical trial comparing clinical outcomes for patients with unruptured large/giant intracranial aneurysms treated with either conventional stent-assisted coiling or flow diverter implantation. A total of 124 patients who fulfill the inclusion and exclusion criteria will be randomized into either a treatment group or a control group in the ratio of 1:1. The treatment group will receive Tubridge implantation alone or combined with bared coils, and the control group will be treated with stent-assisted coiling (bare coils). The primary endpoint will be the complete occlusion rate at 6-month follow-up. Secondary endpoints include the immediate technique success rate, overall mortality, adverse events (ischemic stroke or intracranial bleeding) within 30 days, 90 days and 1 year post-operation, and the rate of intra-stent stenosis and thrombosis 6 months post-operation. DISCUSSION: This prospective trial may provide more information on the safety and efficacy of the Tubridge flow diverter and may potentially change the strategy for treatment of large or giant aneurysms. TRIAL REGISTRATION: The trial is registered on the Chinese Clinical Trial Registry: ChiCTR-TRC-13003127.

The interaction between stent(s) implantation, PICA involvement, and immediate occlusion degree affect symptomatic intracranial spontaneous vertebral artery dissection aneurysm (sis-VADA) recurrence after reconstructive treatment with stent(s)-assisted coiling.

OBJECTIVES: We aimed to evaluate risk factors of sis-VADAs recurrence after reconstructive treatment based on 113 reconstructed lesions. METHODS: A total of 111 patients (M:F = 68:43; median age, 47 years) with 113 sis-VADAs underwent reconstruction from October 2000 to March 2011, using stent(s) and coils. Treatments and predictors of recurrence were retrospectively analysed. RESULTS: Fifty-eight sis-VADAs underwent single-stent treatment, and the remaining 55 sis-VADAs underwent treatment with 2-4 overlapping stents. Follow-up angiography was available for 94 sis-VADAs 12 -78 months, with recurrence in ten patients, including seven angiographic recurrences and three post-treatment haemorrhagic recurrences. A higher rate of post-treatment recurrence was observed in the single stent group than in the multiple stents group (p = 0.010). The interaction between stent (s) implantation and immediate occlusion degree (odds ratio [OR] =3.152; 95% confidence interval [CI], 1.293-7.686; p = 0.012), between stent (s) implantation and the posterior inferior cerebellar artery (PICA) involvement (OR = 4.607; 95% CI, 1.172-18.113; p = 0.029), and between PICA involvement and immediate occlusion degree (OR = 5.018; 95% CI, 1.263-19.933; p = 0.022) affect recurrence in the reconstructed sis-VADAs. CONCLUSIONS: This single centre cohort study indicated that the interaction effect between stent (s) implantation, PICA involvement, and immediate occlusion degree were closely associated with recurrence after reconstructive treatment of sis-VADA. KEY POINTS: The interaction between stent (s) and immediate occlusion degree affect aneurysmal recurrence. The interaction between stent and PICA involvement affect aneurysmal recurrence. The interaction between PICA involvement and immediate occlusion degree affect aneurysmal recurrence.

Role of CT perfusion imaging in evaluating the effects of multiple burr hole surgery on adult ischemic Moyamoya disease.

INTRODUCTION: To evaluate the effects of the multiple burr hole (MBH) revascularization on ischemic type adult Moyamoya disease (MMD) by computed tomography perfusion (CTP). METHODS: Eighty-six ischemic MMD patients received CTP 1 week before and 3 weeks after MBH operation. Fifty-seven patients received it again at 6 month and underwent digital subtraction angiography (DSA) and mRS follow-up. Cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP), and relative values of ischemic symptomatic hemispheres were measured. Differences in pre- and post-surgery perfusion CT values were assessed. RESULTS: There were significant differences of CBF, TTP, and relative time to peak (rTTP) in ischemic hemisphere between 1 week before and 3 weeks after surgery, and no significant difference in relative cerebral blood flow (rCBF), CBV, relative cerebral blood volume (rCBV), MTT, relative mean transit time (rMTT). According to whether there was symptom improvement or not on 3 weeks after MBH, the rTTP value was not statistically significant in the patients whose symptoms were not improved at all on 3 weeks after operation. Six-month follow-up showed that CBF, rCBF, and rCBV values were significantly higher than those before operation. Postoperative MTT, TTP, rMTT, and rTTP values were significantly lower than those before operation. CONCLUSION: CTP is a sensitive method to obtain functional imaging of cerebral microcirculation, which can be a noninvasive assessment of the abnormalities of intracranial arteries and cerebral perfusion changes in MMD before and after surgery. CBF and TTP map, especially the relative values of TTP, seems to have the capability of being quite sensitive to the presence of altered brain perfusion at early time after indirect revascularization.

Decreased miR-106a inhibits glioma cell glucose uptake and proliferation by targeting SLC2A3 in GBM.

BACKGROUND: MiR-106a is frequently down-regulated in various types of human cancer. However the underlying mechanism of miR-106a involved in glioma remains elusive. METHODS: The association of miR-106a with glioma grade and patient survival was analyzed. The biological function and target of miR-106a were determined by bioinformatic analysis and cell experiments (Western blot, luciferase reporter, cell cycle, ntracellular ATP production and glucose uptake assay). Finally, rescue expression of its target SLC2A3 was used to test the role of SLC2A3 in miR-106a-mediated cell glycolysis and proliferation. RESULTS: Here we showed that miR-106a was a tumor suppressor miRNA was involved in GBM cell glucose uptake and proliferation. Decreased miR-106a in GBM tissues and conferred a poor survival of GBM patients. SLC2A3 was identified as a core target of miR-106a in GBM cells. Inhibition of SLC2A3 by miR-106a attenuated cell proliferation and inhibited glucose uptake. In addition, for each biological process we identified ontology-associated transcripts that significantly correlated with SLC2A3 expression. Finally, the expression of SLC2A3 largely abrogated miR-106a-mediated cell proliferation and glucose uptake in GBM cells. CONCLUSIONS: Taken together, miR-106a and SLC2A3 could be potential therapeutic approaches for GBM.

Reconstructive Treatment of Ruptured Intracranial Spontaneous Vertebral Artery Dissection Aneurysms: Long-Term Results and Predictors of Unfavorable Outcomes.

INTRODUCTION: Few studies focused on predictors of unfavorable outcomes (modified Rankin Scale, 2-6) after reconstructive treatment of the ruptured intracranial spontaneous vertebral artery dissection aneurysms (ris-VADAs), which was evaluated based on 57 reconstructed lesions in this study. METHODS: Results of 57 consecutive patients (M:F = 29∶28; median age, 48 years; range, 27 to 69 years) harboring 57 ris-VADAs, which were treated with coils combined with single stent(n = 32), double overlapping stents (n = 16), and triple overlapping stents (n = 9) between October 2000 to March 2011, were retrospectively reviewed and analyzed. RESULTS: The available (n = 54) mean durations of angiographic and clinical follow-ups were 27 months (range, 12 to 78) and 62 months (range, 12 to 132), respectively. The involvement of PICA (p = 0.004), size of lesions (p = 0.000), quantity of stent (p = 0.001), and coil type (p = 0.002) affected the immediate obliteration grade, which was only risk factor for angiographic recurrences (p = 0.031). Although the post-treatment outcomes did not differ between single stent and multiple stents (p = 0.434), 5 angiographic recurrences, 1 rebleeding and 1 suspected rebleeding, all occurred in partial obliteration after single-stent-assisted coiling. Progressive thrombosis and in-stent obliteration were not detected on follow-up angiograms. Older age (odds ratio [OR] = 1.090; 95% confidence interval [CI], 1.004-1.184; p = 0.040) and unfavorable Hunt-Hess scale (OR = 4.289; 95%CI, 1.232-14.933; p = 0.022) were independent predictors of unfavorable outcomes in the reconstructed ris-VADAs. CONCLUSIONS: Immediate obliteration grade was only risk factor for angiographic recurrence after reconstructive treatment. Unfavorable Hunt-Hess grade and older age were independent predictors of unfavorable outcomes in ris-VADAs.

Endothelial progenitor cells contribute to neointima formation in rabbit elastase-induced aneurysm after flow diverter treatment.

AIMS: Endothelial progenitor cells (EPCs) are involved in vascular repair and homeostasis after vascular injuries. In this study, we aimed to explore whether bone marrow (BM)-derived EPCs contribute to neointima formation and reendothelialization in rabbit elastase-induced aneurysm after flow diverter treatment. METHODS: Elastase-induced aneurysms were created in New Zealand male rabbits. Three weeks after model creation, flow diverter was implanted to cover the induced aneurysm neck. Autologous EPCs were isolated from bone marrow, expanded ex vivo, double labeled with Hoechst 33,342 and CFSE(carboxyfluorescein diacetate succinimidyl ester), and transplanted transvenously into the rabbits. The rabbits were assigned into three groups. The first group received autologous transfusion of double-labeled EPCs from the first day after stent implantation, and the second group received transfusion from the fifteenth day. The autologous transfusion was given at a 3-day interval and continued for 2 weeks. Fluorescence-labeled cells were tracked under fluorescence microscope at the aneurysm neck and parent artery in the two groups. The third group was established as control group without EPCs transplantation. Scanning electron microscope was used to investigate the reendothelialization rate between the former two groups and the control group. RESULTS: In the first group, double-positive EPCs were found in 3/5 rabbits and mainly located in the subendothelial space and around the stent struts. In the second group, double-positive EPCs were found in 2/5 rabbits and mainly located on the surface of neointima. More endothelial-like cells were observed on the neointima of aneurysm neck and stented parent artery in the groups with EPCs transplantation than control group without EPCs transplantation, but the difference on the number of these cells did not reach statistical significance. CONCLUSIONS: BM-derived EPCs participate in neointima formation and reendothelialization in elastase-induced aneurysm after flow diverter treatment. The EPCs may differentiate into different cell types according to the stages of neointima formation in vivo.

[Safety and short-term results of stent-assisted angioplasty for the treatment of intracranial arterial stenosis].

OBJECTIVE: To evaluate the safety and short-term outcome of endovascular stent-assisted angioplasty for the treatment of intracranial arterial stenosis. METHODS: Angioplasty and stent placement were administered to treat 46 patients with lesions of atherosclerotic intracranial stenosis, including 16 lesions of basilar artery, 12 of vertebral artery, 13 of internal carotid artery and 9 of middle cerebral artery. RESULTS: Technical success was achieved in 49 of 50 vessels (98%), with no procedure-related death or cerebral ischemic attack. Extracranial internal carotid artery dissection occurred in 1 patient and was successfully treated with a self-expand stent. One patient had subarachnoid hemorrhage because of perforation by microwire with no permanent neurologic deficit, and another 2 patients had groin hematoma. Angiographic examination immediately after stenting revealed that the stenosis rate was significantly reduced (72.4% +/- 12.3% vs 10.6% +/- 7.8%). There was no cerebral ischemic attack in the 37 patients who were clinically followed up (6 - 18 months, mean of 8.5 months). CONCLUSION: Angioplasty and stenting for the treatment of intracranial stenosis is safe and feasible, and it may be favorable for decreasing the incidence of ischemic attack.

[Treatment of posterior-communicating wide-necked aneurysms with endovascular stent and Guglielmi detachable coils].

OBJECTIVE: To summarize our clinical experience in treating posterior-communicating wide-necked aneurysms using endovascular stent and Guglielmi detachable coils (GDCs). METHODS: The coronary stents were implanted across the neck of 32 posterior-communication wide-necked aneurysms. Microcatheters were introduced into the aneurysm sac through stent mesh, GDCs were used to embolize aneurysms. RESULTS: All operations were successful. Total occlusion was achieved in 26 patients, over 90% in 4, 60 - 70% in 2. The patients were perfectly recovered with patency of the parent arteries. CONCLUSION: Endovascular therapy combined with stent implatation and GDC placement is a valid approach to the treatment of posterior-communication wide-necked aneurysms.