Current Strategies in the Treatment of Intracranial Large and Giant Aneurysms

Introduction: Very large and giant aneurysms are among the most challenging cerebrovascular pathologies in neurosurgery.Methods: The aim of this paper is to review the current literature on the management of very large and giant aneurysms and to describe representative cases illustrating possible treatment strategies.Results: In view of the poor natural history, active management using multiprofessional individualized approaches is required to achieve aneurysm occlusion, relief of mass effect, and obliteration of the embolic source. Both reconstructive (clipping, coiling, stent-assisted coiling, flow diversion [FD]) and deconstructive techniques (parent artery occlusion [PAO], PAO in conjunction with bypass surgery, and strategies of flow modification) are available to achieve definitive treatment with acceptable morbidity.Conclusions: Patients harboring such lesions should be managed at high-volume cerebrovascular centers by multidisciplinary teams trained in all techniques of open and endovascular neurosurgery.

Brain Arteriovenous Malformations Classifications: A Surgical Point of View

Brain arteriovenous malformations (AVMs) classification has been the subject of extensive discussion. The aim of our work was to review the main classification schemes proposed in the literature, which can be summarized in four main groups: (a) traditional schemes oriented to evaluate the operability of AVMs have been joined by (b) specific classifications that evaluate the outcome and the predictability of obliteration of other treatment modalities and (c) others that evaluate the outcome of intracerebral hemorrhages in ruptured AVMs. Eventually, (d) topographical classifications that categorize the subtypes of AVMs located in specific anatomical regions have been drawn. For each classification, we discuss the implications on surgical management.

Characteristic Pattern of the Cerebral Hemodynamic Changes in the Acute Stage After Combined Revascularization Surgery for Adult Moyamoya Disease: N-isopropyl-p-[123I] iodoamphetamine Single-Photon Emission Computed Tomography Study

Objective: Surgical revascularization for moyamoya disease (MMD) prevents cerebral ischemic attack by improving cerebral blood flow (CBF) and could also reduce the risk of re-bleeding in hemorrhagic-onset patients. We sought to clarify the cerebral hemodynamic changes in the acute stage after revascularization surgery for adult MMD.Materials and methods: The present study includes 54 consecutive adult patients with MMD (21–76 years old, 43.1 average), undergoing superficial temporal artery-middle cerebral artery anastomosis with indirect pial synangiosis on 65 affected hemispheres. We prospectively performed single-photon emission computed tomography (SPECT) at postoperative day (POD) 1 and 7 of 65 surgeries. Perioperative management was conducted with strict blood pressure control (100–130 mmHg) and minocycline hydrochloride administration.Results: The outcome of 65 surgeries was favorable except for one (1.5%), which manifested as delayed intracerebral hemorrhage due to local hyperperfusion. The postoperative SPECT revealed the characteristic CBF improvement pattern with transient local hyperperfusion (POD1) and subsequent distribution of CBF in wider vascular territory (POD7) on 37 hemispheres (56.9%, 37/65).Conclusion: The revascularization surgery is a safe and effective treatment for adult MMD, while transient local hyperperfusion should be strictly managed by intensive perioperative care.

Surgical Simulation with Three-Dimensional Fusion Images in Patients with Arteriovenous Malformation

In arteriovenous malformation (AVM) surgery, vessel structures should be well evaluated with angiography. However, with conventional angiography, it is sometimes difficult to distinguish each feeder and its feeding territory in the nidus. In this study, we used two software systems to create three-dimensional (3D) fusion images using multiple imaging modalities and evaluated their clinical use. In the AVM patient, data were obtained from 3D rotational angiography, rotational venography, computed tomography (CT), and magnetic resonance imaging (MRI) and superimposed into 3D fusion images using imaging software (iPLAN and Avizo). Virtual surgical fields that were quite similar to the real ones were also created with these software programs. Compared with fusion images by iPLAN, those by Avizo have higher resolution and can demarcate not only each feeder but also its supplying territory in the nidus with different colors.In conclusion, 3D fusion images in AVM surgery are helpful for simulation, even though it takes time and requires special skill to create them.

Computational Fluid Dynamics for Cerebral Aneurysms in Clinical Settings

Hemodynamics is thought to play an important role in the pathogenesis of cerebral aneurysms and recent development of computer technology makes it possible to simulate blood flow using high-resolution 3D images within several hours. A lot of studies of computational fluid dynamics (CFD) for cerebral aneurysms were reported; therefore, application of CFD for cerebral aneurysms in clinical settings is reviewed in this article.CFD for cerebral aneurysms using a patient-specific geometry model was first reported in 2003 and it has been revealing that hemodynamics brings a certain contribution to understanding aneurysm pathology, including initiation, growth and rupture. Based on the knowledge of the state-of-the-art techniques, this review treats the decision-making process for using CFD in several clinical settings. We introduce our CFD procedure using digital imaging and communication in medicine (DICOM) datasets of 3D CT angiography or 3D rotational angiography. In addition, we review rupture status, hyperplastic remodeling of aneurysm wall, and recurrence of coiled aneurysms using the hemodynamic parameters such as wall shear stress (WSS), oscillatory shear index (OSI), aneurysmal inflow rate coefficient (AIRC), and residual flow volume (RFV).

Microneurosurgical Management of Posterior Inferior Cerebellar Artery Aneurysms: Results of a Consecutive Series

Aneurysms of the posterior inferior cerebellar artery (PICA) are uncommon. The complex anatomy of PICA and its intimate relationships with medulla, lower cranial nerves, and jugular tubercle makes the surgical treatment of these aneurysms fascinating. The reported is study aimed at a critical review of the overall results of a personal series of PICA aneurysms, treated by the senior author, R. Galzio. Demographics, charts, videos, outcome, and follow-up of a cohort of PICA aneurysms managed in the last 10 years were retrospectively analyzed, focusing only upon those treated with microneurosurgery. Twenty-five patients, harboring a single aneurysm, were operated on. Fifteen aneurysms were ruptured. Nineteen were proximal, all of these being been treated through a far-lateral approach. Trans-condylar or trans-tubercular variants were rarely necessary and however reserved to peculiar cases. Twenty-three aneurysms underwent direct treatment consisting of clip ligation. At 6-month follow-up, 60% of patients had a modified Rankin Score (mRS) of 0–2. Given the high anatomical variability of both PICA and patients’ bony anatomy, a case-by-case meticulous preoperative imaging evaluation is mandatory for the choice of the most suitable and tailored surgical corridor which, in turn, is pivotal to achieve the best outcome.

Spinal Dural AVFs: Classifications and Advanced Imaging

Spinal dural arteriovenous fistulas (SDAVFs) are the most common vascular shunts of the spine. They occur predominantly in men (more than 80%), commonly involve the thoracolumbar spine, and usually cause progressive myelopathy because of venous congestion of the spinal cord. Recent advanced imaging technology can visualize the detailed angioarchitecture of the spinal cord, and this provides more information of the regional microanatomy related with the shunt disease. We retrospectively analyzed the location of the shunt with adjacent vasculatures and assessed the efficacy and the sensitivity of each imaging modality. Based on these data, a new concept of classification for SDAVFs was reviewed.

History of the European-Japanese Cerebrovascular Congress

The European-Japanese Cerebrovascular Congress originally started as a Swiss-Japanese joint conference on cerebral aneurysm. The Congress was held in Zürich, Switzerland, from 5–7 May 2001 with Prof. Y. Yonekawa of Zürich and Prof. Y. Sakurai of Sendai as the presidents.Three years later, in July of 2004, the second meeting was held at Zürich again with wide-ranging conference topics on cerebral stroke surgery.The third meeting at Zürich in 2006 was the key congress for future development. The conference was expanded to the European-Japanese Joint Conference for Stroke Surgery.As the year of 2006 was the 70th Anniversary of the Department of Neurosurgery, University Hospital Zürich, Prof. Krayenbühl, Prof. Yasargil, and Prof. Yonekawa introduced the impressive history of the Department of Neurosurgery at the conference.At the fourth European-Japanese Joint Conference on Stroke Surgery we moved from Zürich to the Nordic city of Helsinki, with Prof. Juha Hernesniemi as the conference president.The fifth joint conference was held at Düsseldolf am Rein with Prof. Hans-Jakob Steiger as the Conference president.The sixth conference, named “The European-Japanese Stroke Surgery Conference” (EJSSC), was held in Utrecht, The Netherlands. Professor Luca Regli and Prof. Gabriel Rinkel were the conference presidents.The seventh European-Japanese Stroke Surgery Conference (EJSSC) was held in Verona, Italy with the presidents Prof. Alberto Pasqualin and Prof. Giampietro Pinna.The eighth European-Japanese Cerebrovascular Congress (EJCVC) came back to Zürich in the year 2016 with Prof. Luca Regli as the president.The ninth European-Japanese Cerebrovascular Congress (EJCVC) was held in the historical room of Grande Ospedale Metropolitano Niguarda Milan, Italy, with Prof. Marco Cenzato as the president.The tenth European-Japanese Cerebrovascular Congress (EJCVC) will be held in Kyoto. It will be the first meeting of the EJCVC in Japan.Publication of the proceeding books of the conference as supplements of ACTA Neurochirurgica is one of the main reasons that we have been able to continue this conference for almost 20 years. We sincerely thank Prof. Steiger for his continuous and generous cooperation as the series Editor of ACTA Neurochirurgica.

Outcomes of Balloon Angioplasty and Stenting for Symptomatic Intracranial Atherosclerotic Stenosis at a High Volume Center

Purpose: This study investigated the periprocedural complication rates, long-term outcome, and restenosis of endovascular treatment for intracranial atherosclerotic stenosis (ICS) at our hospital.Methods: We retrospectively analyzed the clinical data of 217 patients comprising 256 endovascular treatments for high-grade symptomatic ICS. The lesion was located in the internal carotid artery in 77, the middle cerebral artery in 111, the basilar artery in 29, and the vertebral artery in 39. Patients were divided into two groups, before (early-phase group, 1999–2013) and after approval of Wingspan (late-phase group, 2014–2017).Results: In the early-phase group (n = 163), 157 lesions were treated by balloon angioplasty and 31 (17%) by coronary stenting. In the late-phase group (n = 54), 33 lesions were treated by balloon angioplasty and 35 (52%) by Wingspan stenting. Overall technical success rates were 96% in the balloon angioplasty and 100% in stenting groups. The 30-day rate of stroke, TIA, and death were 4.8% in the early-phase group and 4.4% in the late-phase group. There was one minor stroke and two TIAs during the follow-up period in the late-phase group.Conclusions: Endovascular treatment for symptomatic ICS in this study appeared to be safe and effective if patients are properly selected. However, future well-designed randomized trials with different techniques and modified patients selection criteria are certainly warranted.

Intraoperative BOLD-fMRI Cerebrovascular Reactivity Assessment

Blood oxygenation-level dependent cerebrovascular reactivity (BOLD-CVR) has gained attention in recent years as an effective way to investigate CVR, a measure of the hemodynamic state of the brain, with high spatial and temporal resolution. An association between impaired CVR and diverse pathologies has been observed, especially in ischemic cerebrovascular diseases and brain gliomas. The ability to obtain this information intraoperatively is novel and has not been widely tested. We report our first experience with this intraoperative technique in vascular and oncologic neurosurgical patients, discuss the results of its feasibility, and the possible developments of the intraoperative employment of BOLD-CVR.