Characteristics and surgical treatment of dolichoectatic and fusiform aneurysms

Combined Treatment of Large Fusiform A2 Aneurysm with End-to-Side Extended Superficial Temporal Artery-A3 Bypass Using Contralateral Superficial Temporal Artery Interposition Graft and Endovascular Aneurysm Trapping: A Case Report and Literature Review

Background: A2 fusiform aneurysms present certain management difficulties with conventional microsurgical or endovascular approaches due to the circumferential morphology, deep location within the interhemispheric fissure, and narrow surgical corridor. Methods: We present a case of a large (>10 cm) fusiform aneurysm in the right A2 segment treated with a combined method consisting of an extended superficial temporal artery to A3 bypass using a contralateral superficial temporal artery interposition graft and subsequent endovascular trapping of the aneurysm. To treat the aneurysm, endovascular trapping following revascularization was planned. During surgery, as the left A3 segment was not available, a superficial temporal artery to A3 bypass was performed. The right frontal branch (donor) was extended with the left frontal branch as a free interposition graft (end-to-end anastomosis) and then anastomosed with the right A3 segment (end-to-side anastomosis). At 6 days after surgery, after confirming the good patency of the bypass graft, endovascular aneurysm trapping was performed. Results: At 8 days after surgery, the patient was discharged without any neurologic deficits. Follow-up digital subtraction angiography at 12 months after surgery showed the good patency of the bypass graft with complete occlusion of the aneurysm. Conclusions: Our case demonstrates the feasibility and effectiveness of a combined microsurgical-endovascular approach as a management strategy for deeply located A2 fusiform aneurysm. When in situ bypass is not possible, an extended superficial temporal artery donor may be considered.

C2-P2 Bypass: Technical Assessment of Petrous Carotid Artery to Posterior Cerebral Artery Interpositional Bypass Through the Combined Transcochlear-Subtemporal Approach as a Part of Microsurgical Treatment for Dolichoectatic Vertebrobasilar Artery Aneurysms

BACKGROUND AND OBJECTIVES

Managing dolichoectatic vertebrobasilar artery aneurysms requires a multifaceted approach. Revascularization of the posterior circulation with a high-flow bypass is part of the flow reversal paradigm. Performing a robust high-flow bypass and addressing the aneurysm through the same approach smooths the operative intervention. This study assessed the anatomic feasibility of accessing the basilar trunk and aneurysm simultaneously to revascularize the posterior circulation using a petrous internal carotid artery (pICA)-posterior cerebral artery (PCA) interpositional bypass through a complete petrosectomy.

METHODS

Six embalmed cadaveric heads (12 sides) underwent a combined extended transcochlear-subtemporal approach to expose the pICA and P2 PCA. A pICA (side-to-end) graft (end-to-side) PCA bypass was attempted. The lengths of the vessels relevant to the bypass and the graft length were measured.

RESULTS

The bypass was successfully completed in all specimens. The mean exposed lengths of the pICA and PCA were 21.3 and 20.0 mm, respectively. The mean length of the perforator-free zone on PCA was 11.2 mm. The mean length of the interposition graft was 36.6 mm.

CONCLUSION

The transcochlear approach can be used to expose the pICA as a donor for a high-flow bypass to the PCA as part of the treatment paradigm for dolichoectatic vertebrobasilar artery aneurysms. Careful patient selection and extensive knowledge of skull base anatomy are mandatory for this strategy.

Statins may Decrease Aneurysm wall Enhancement of Unruptured Fusiform Intracranial Aneurysms: A high-resolution 3T MRI Study

Inflammation plays an integral role in the formation, growth, and progression to rupture of unruptured intracranial aneurysms. Aneurysm wall enhancement (AWE) in high-resolution magnetic resonance imaging (HR-MRI) has emerged as a surrogate biomarker of vessel wall inflammation and unruptured intracranial aneurysm instability. We investigated the correlation between anti-inflammatory drug use and three-dimensional AWE of fusiform intracranial aneurysms (FIAs). We retrospectively analyzed consecutive patients with FIAs in our database who underwent 3T HR-MRI at three Chinese centers. FIAs were classified as fusiform-type, dolichoectatic-type, or transitional-type. AWE was objectively defined using the aneurysm-to-pituitary stalk contrast ratio in three-dimensional space by determining the contrast ratio of the average signal intensity in the aneurysmal wall and pituitary stalk on post-contrast T1-weighted images. Data on aneurysm size, morphology, and location, as well as patient demographics and comorbidities, were collected. Univariate and multivariate logistic regression analyses were performed to determine factors independently associated with AWE of FIAs on HR-MRI. In total, 127 FIAs were included. In multivariate analysis, statin use (β = -0.236, P = 0.007) was the only independent factor significantly associated with decreased AWE. In the analysis of three FIA subtypes, the fusiform and transitional types were significantly associated with statin use (rs = -0.230, P = 0.035; and rs = -0.551, P = 0.010; respectively). It establishes an incidental correlation between the use of statins daily for ≥ 6 months and decreased AWE of FIAs. The findings also indicate that the pathophysiology may differ among the three FIA subtypes.

Treatment strategies and outcomes for intracranial fusiform aneurysms: A systematic review and meta-analysis

BACKGROUND

Fusiform aneurysms are a distinct subgroup of intracranial aneurysms with unique characteristics and pose a treatment challenge compared to common saccular aneurysms. Traditionally, surgery was the main treatment; however, endovascular techniques are gaining favor.

METHODS

We searched major databases for studies on treatment, clinical outcomes, and radiological outcomes of intracranial fusiform aneurysms published before May 31st, 2023 in order to compare surgical Vs endovascular treatment strategies. Pooled data analysis was performed using a random-effects model.

RESULTS

This systematic review and meta-analysis analyzed 1704 patients with 1737 fusiform aneurysms from 63 studies. Endovascular treatment, particularly stent-assisted coiling and stenting, emerged as the preferred approach with lower mortality and complication rates compared to surgery. Aneurysm location played a role in outcomes, with anterior circulation aneurysms generally faring better. Deconstructive strategies, designed to occlude the parent artery, carried a doubled risk of complications compared to reconstructive approaches, which aim to preserve blood flow (OR: 2.188; 95% CI: 1.474-3.248; p < 0.001).

CONCLUSION

Endovascular techniques are becoming the mainstay of treatment for fusiform aneurysms, offering improved safety and efficacy compared to surgery. Anterior circulation location and reconstructive strategies are associated with better outcomes. However, no significant differences in OR for early complete occlusion were found between surgery and endovascular techniques at discharge and follow-up with very low heterogeneity among studies.

Hyperintense vessel sign in vertebrobasilar dolichoectasia

Vertebrobasilar dolichoectasia (VBD) is a rare condition characterised by ectasia, elongation and tortuosity in the vertebrobasilar arteries. VBD prevalence ranges from 0.05% to 18%. A possible interplay between vascular risk factors and a predisposing genotype could alter the balance between tunica media matrix metalloproteinases and antiprotease activity. VBD is characterised by the disruption of smooth muscle atrophy, reticular fibre degeneration and multiple gaps in the inner elastic lamina, causing thinning of the tunica media and arterial wall weakening and deformation. VBD can be asymptomatic. VBD is often characterised by ischaemic stroke, intracerebral haemorrhage, brainstem/cranial nerve compression and subarachnoid haemorrhage. Vascular events are the most common clinical manifestation. Slow arterial blood flow results in hyperintense vascular signals, which are linked with a larger infarct and a higher risk of cerebral bleeding. Treatment for VBD is difficult. Currently, there are no specific treatments for VBD, and the available treatments focus on the consequences.

Complex intracranial aneurysms: a DELPHI study to define associated characteristics

PURPOSE

Intracranial aneurysms present significant health risks, as their rupture leads to subarachnoid haemorrhage, which in turn has high morbidity and mortality rates. There are several elements affecting the complexity of an intracranial aneurysm. However, criteria for defining a complex intracranial aneurysm (CIA) in open surgery and endovascular treatment could differ, and actually there is no consensus on the definition of a "complex" aneurysm. This DELPHI study aims to assess consensus on variables defining a CIA.

METHODS

An international panel of 50 members, representing various specialties, was recruited to define CIAs through a three-round Delphi process. The panelists participated in surveys with Likert scale responses and open-ended questions. Consensus criteria were established to determine CIA variables, and statistical analysis evaluated consensus and stability.

RESULTS

In open surgery, CIAs were defined by fusiform or blister-like shape, dissecting aetiology, giant size (≥ 25 mm), broad neck encasing parent arteries, extensive neck surface, wall calcification, intraluminal thrombus, collateral branch from the sac, location (AICA, SCA, basilar), vasospasm context, and planned bypass (EC-IC or IC-IC). For endovascular treatment, CIAs included giant size, very wide neck (dome/neck ratio ≤ 1:1), and collateral branch from the sac.

CONCLUSIONS

The definition of aneurysm complexity varies by treatment modality. Since elements related to complexity differ between open surgery and endovascular treatment, these consensus criteria of CIAs could even guide in selecting the best treatment approach.

Exploring the latest findings on endovascular treatments for giant aneurysms: a review

Giant intracranial aneurysms represent a very challenging aspect of aneurysmal pathophysiology with very high mortality and morbidity if left untreated. Their variety in clinical presentation (subarachnoid hemorrhage, cranial nerve palsy, etc.) and pathological and imaging properties (location, anatomy, presence of collateral circulation) pose serious questions regarding the best treatment option. Admirable advances have been achieved in surgical techniques, while endovascular modalities with flow diversion techniques have become widely used. However, there is still lack of data regarding whether a single endovascular technique can be the universal treatment for such cases. In this review, we aim to summarize the current funds of knowledge concerning giant intracranial aneurysms and the role of endovascular management in their treatment.

Pathology-based brain arterial disease phenotypes and their radiographic correlates

INTRODUCTION

Brain arterial diseases, including atherosclerosis, vasculitis, and dissections, are major contributors to cerebrovascular morbidity and mortality worldwide. These diseases not only increase the risk of stroke but also play a significant role in neurodegeneration and dementia. Clear and unambiguous terminology and classification of brain arterial disease phenotypes is crucial for research and clinical practice.

MATERIAL AND METHODS

This review aims to summarize and harmonize the terminology used for brain large and small arterial phenotypes based on pathology studies and relate them to imaging phenotypes used in medical research and clinical practice.

CONCLUSIONS AND RESULTS

Arteriosclerosis refers to hardening of the arteries but does not specify the underlying etiology. Specific terms such as atherosclerosis, calcification, or non-atherosclerotic fibroplasia are preferred. Atherosclerosis is defined pathologically by an atheroma. Other brain arterial pathologies occur and should be distinguished from atherosclerosis given therapeutic implications. On brain imaging, intracranial arterial luminal stenosis is usually attributed to atherosclerosis in the presence of atherosclerotic risk factors but advanced high-resolution arterial wall imaging has the potential to more accurately identify the underlying pathology. Regarding small vessel disease, arteriosclerosis is ambiguous and arteriolosclerosis is often used to denote the involvement of arterioles rather than arteries. Lipohyalinosis is sometimes used synonymously with arteriolosclerosis, but less accurately describes this common small vessel thickening which uncommonly shows lipid. Specific measures of small vessel wall thickness, the relationship to the lumen as well as changes in the layer composition might convey objective, measurable data regarding the status of brain small vessels.

A case of bilateral vertebral artery dissection treated by bilateral surgical occlusion and low-flow bypass

Background

Bilateral vertebral artery dissection aneurysm (VADA) is a rare condition that leads to severe stroke. However, the surgical strategy for its treatment is controversial because the pathology is very complicated and varies in each case. Here, we report a case of bilateral VADA that was successfully treated with staged bilateral VADA occlusion and low-flow bypass.

Case Description

A Japanese man in his 40s presented with bilateral VADA with subarachnoid hemorrhage. He had only mild headaches without any other neurological deficits. Subsequently, the ruptured left VADA was surgically trapped. However, on postoperative day 11, the contralateral VADA enlarged. The right VADA was then proximally clipped via a lateral suboccipital approach. Furthermore, a superficial temporal artery-superior cerebellar artery bypass was performed through a subtemporal approach in advance to preserve cerebral flow in the posterior circulation. The bilateral VADA was obliterated, and the patient had an uneventful postoperative course during the 1-year and 6-month follow-up period.

Conclusion

Bilateral VADA can be successfully treated with staged bilateral VADA obstruction and low-flow bypass. In this case, as the posterior communicating arteries were the fetal type and the precommunicating segments of the posterior cerebral arteries (P1) were hypoplastic, a low-flow bypass was used to supply the basilar and cerebellar arteries, except the posterior cerebral and posterior inferior cerebellar arteries. Furthermore, low-flow bypass is a less invasive option than high-flow bypass.

Microcurrent wave alleviates mouse intracranial arterial dolichoectasia development

Intracranial arterial dolichoectasia (IADE) is associated with the interaction of hypertension and inflammation, and microcurrent can be effective in hypertension. Therefore, this study aimed to investigate the therapeutic effect of microcurrent electrical stimulation in a mouse IADE model. This study randomly categorized 20 mice into five groups: group 1-C (healthy control), group 2-D (IADE model), group 3-M + D (microcurrent administration before nephrectomy and until brain surgery), group 4-D + M (microcurrent administration for 4 weeks following brain surgery), and group 5-M (microcurrent administration for 4 weeks). Cerebral artery diameter and thickness and cerebral arterial wall extracellular matrix components were assessed. Among the five groups, group 2-D showed significantly higher cerebral arterial wall diameter (117.79 ± 17.05 µm) and proportion of collagen (42.46 ± 14.12%) and significantly lower arterial wall thickness (9.31 ± 2.26 µm) and proportion of smooth muscle cell (SMC) and elastin in the cerebral arterial wall (SMC: 38.05 ± 10.32%, elastin: 11.11 ± 6.97%). Additionally, group 4-D + M exhibited a non-significantly lower diameter (100.28 ± 25.99 µm) and higher thickness (12.82 ± 5.17 µm). Group 5-M demonstrated no evidence of toxicity in the liver and brain. The pilot study revealed that microcurrent is effective in preventing IADE development, although these beneficial effects warrant further investigation.

Targeting myeloperoxidase to stabilize unruptured aneurysm: an imaging-guided approach

Inflammation plays a key role in pathogenesis and rupture of aneurysms. Non-invasively and dynamically monitoring aneurysm inflammation is critical. This study evaluated myeloperoxidase (MPO) as an imaging biomarker and therapeutic target for aneurysm inflammation using an elastase-induced rabbit model treated with or without 4-aminobenzoic acid hydrazide (ABAH), an irreversible inhibitor of MPO. Myeloperoxidase-sensitive magnetic resonance imaging (MRI) using Mn-TyrEDTA, a peroxidase activity-dependent contrast agent, revealed weak contrast enhancement in contralateral arteries and decreased contrast enhancement in aneurysm walls with ABAH treatment, indicating MPO activity decreased and inflammation mitigated. This was supported by reduced immune cell infiltration, matrix metalloproteinases (MMP-2 and - 9) activity, ROS production and arterial wall destruction on histology. Finally, the aneurysm expansion rate remained < 50% throughout the study in the ABAH(+) group, but increased gradually in the ABAH(-) group. Our results suggest that inhibition of MPO attenuated inflammation and expansion of experimental aneurysm and MPO-sensitive MRI showed promise as a noninvasive tool for monitoring aneurysm inflammation.

Treatment of an Intracranial Fusiform Vertebral Aneurysm Using the MVP® Micro Vascular Plug System as an Adjunct to Pipeline(TM) Embolization: Technical Case Instruction

Fusiform and dolichoectatic aneurysms pose unique challenges in treatment, often requiring alternative approaches compared to saccular aneurysms. Microsurgical options like clipping or a bypass can be difficult, leading to the advancement of endovascular techniques. Flow-diverting stents and vessel sacrifice with detachable coils have shown efficacy in reconstruction. The MVP® Micro Vascular Plug System (Medtronic, Minneapolis, Minnesota, USA) offers a resheathable plug for vessel occlusion through electrolytic detachment. This case report illustrates the supplementary application of MVP® subsequent to flow diverter (FD) stenting, resulting in the effective endovascular management of a fusiform aneurysm affecting both vertebral arteries (VA), following unsuccessful coil vessel sacrifice treatment. A 61-year-old female presented with an unruptured fusiform aneurysm in the bilateral vertebral arteries (VAs). Treatment included a flow diverter in the right VA and vessel sacrifice in the left VA using Onyx-18 and coils. Despite initial success, left V4 segment recanalization occurred. Endovascular treatment, deploying two devices and additional coils using the MVP®, halted the flow. Follow-up showed left VA occlusion and reconstruction of the treated right VA, with the patient being discharged without deficits. This case demonstrates a unique approach using MVP® alongside a flow diverter (a PipelineTM Embolization Device (PED), Medtronic) for the treatment of a V4 segment fusiform aneurysm. This innovative technique is an alternative when conventional coil embolization for vessel sacrifice fails. The MVP®'s ease of use and precise delivery render it a feasible and efficacious alternative for treating complex aneurysms.

Clip Reconstruction of Fusiform A1 Segment Aneurysm Using Lateral Supraorbital Approach

Fusiform aneurysms of the anterior cerebral artery are a surgical rarity encountered only occasionally by a neurosurgeon.1,2 Seen most commonly in the vertebrobasilar territory, these aneurysms differ in pathophysiology and clinical presentation from their saccular counterparts. Arterial dissections and atherosclerosis are the leading causes of these aneurysms in young and elderly patients, respectively.3 Patients can present with symptoms related to mass effect/compression of adjacent structures or with ischemic symptoms apart from aneurysm rupture. Management of these aneurysms remains challenging owing to the lack of a distinct neck. Surgical options include clip reconstruction, parent vessel occlusion, or aneurysm trapping with4 and without1 bypass using a branch of the superficial temporal artery. Clipping techniques used for these aneurysms include the use of fenestrated clips, vessel wall reconstruction, and wrapping.5,6 However, due to enormous variations in aneurysm morphology, each case presents a unique challenge; hence neurosurgeons need to be aware of this important entity. Endovascular techniques including parent vessel occlusion or vessel-preserving techniques using coil or flow diverters have also been described,3 but clipping remains the preferred choice for most surgeons worldwide. In Video 1, we present a case of fusiform A1 segment aneurysm in a 34-year-old gentleman and demonstrate how the aneurysm was clipped using a lateral supraorbital approach. He made an uneventful recovery with subtle right lower limb weakness. This video shows the technique and utility of a minimally invasive skull base approach for dealing with a fusiform anterior circulation aneurysm.

Giant Aneurysms: Not So Giant in Behavior

BACKGROUND

Giant intracranial aneurysms (GIAs) are very complex in their behavior and treatment procedure. There are various modalities of treatment. The annual rupture rate of GIA (6%) is higher than that of small aneurysms (1-3%). Neurosurgeons handle these aneurysms during operations.

OBJECTIVE

We tried to analyze the intraoperative rupture rate (IRR) of GIA in relation to small aneurysms. IRR is concerned with the rupture of the aneurysms during operative handling.

MATERIALS AND METHODS

For conducting the study, we compared the IRR of 7 GIAs and 45 small aneurysms during a span of 10 years. All the operations were performed by the same team and the same principal surgeon. IRR was compared by statistical analysis.

RESULT

Z-test was done to compare the two rates: Z = 0.68 and P = 0.49. According to our study, the IRR of GIA is not statistically different from small aneurysms. The IRR of GIA is not higher because of three factors which we have analyzed: 1) layers of intraaneurysmal thrombus, 2) fibrin deposition on the aneurysm wall, and 3) blocked neck of the aneurysm by thrombus.

CONCLUSION

The IRR of GIA is not different from small aneurysms.

Fusiform aneurysms of anterior cerebral artery: center experience and systematic literature review

Fusiform aneurysms of the anterior cerebral artery (ACA) are uncommon, and the natural history of this entity is poorly characterized. Along with our center experience, we conducted a systematic literature review to help shed light on the clinical course of ACA fusiform aneurysms. We queried our institutional database to identify cases with fusiform aneurysms of ACA. In addition, following the PRISMA algorithm, we identified all reported cases published in the English literature from the inception of PubMed until December 2022. We categorized clinical presentations into three categories: (i) traumatic/iatrogenic, (ii) spontaneous symptomatic ruptured/unruptured, and (iii) spontaneous asymptomatic aneurysms. We utilized descriptive statistics. We identified seven cases from our center along with 235 patients from published literature. Blunt trauma was responsible for the development of 19 aneurysms. Sixty-three percent of these aneurysms tend to rupture within 2 weeks from the initial trauma, and despite treatment, only 74% of these patients had good clinical outcomes. Spontaneous symptomatic presentation occurred in 207 patients and was often associated with previous/concomitant ACA dissection. Subarachnoid hemorrhage from ruptured aneurysms was the most common presentation. Spontaneous symptomatic fusiform aneurysm is rapidly evolving lesions, and treatment is necessary. Three of our own cases were treated with an endovascular flow diverter (pipeline) stenting with good outcomes. Spontaneous asymptomatic aneurysms were reported in nine patients. These lesions are often associated with other vascular abnormalities. Treatment included surgical clipping with good clinical outcomes. Instead, four patients from our center database were managed conservatively with equally good outcomes. Our study demonstrates good clinical outcomes when fusiform aneurysms of ACA, especially when symptomatic, are treated promptly with either reconstructive or deconstructive therapies.

Flow diversion for posterior circulation aneurysms: a multicenter retrospective study

Background

The prevalence of intracranial aneurysms is approximately 3% worldwide. Posterior circulation (PC) aneurysms have a higher risk of treatment complications than anterior circulation aneurysms. Improving the survival rate and quality of life of patients with PC aneurysms remains one of the most important issues in the field.

Objectives

Flow diverter (FD) treatment of PC aneurysms remains controversial. We aimed to investigate the effects of FD treatment and analyze differences among different application methods or aneurysm types in PC aneurysms.

Design

This is a multicenter retrospective study.

Methods

Patients with PC aneurysms treated with the pipeline embolization device (PED) or Tubridge embolization device (TED) between 2015 and 2020 in five neurovascular centers were retrospectively enrolled. The primary outcomes were major perioperative complication, clinical outcome, and aneurysm occlusion rates. Univariable and multivariable logistic regression analyses were used to determine the risk factors of each outcome.

Results

In total, 252 aneurysms were included. Major perioperative complication, favorable clinical outcome, and complete occlusion rates were 7.5%, 91.0%, and 79.1%, respectively. Compared with other types of aneurysms, dissecting aneurysms had the best clinical outcome and highest occlusion rate. Both clinical and angiographic outcomes were independently associated with the aneurysm location at the basilar artery. Aneurysm size was not associated with any outcome. TED had similar clinical and angiographic outcomes compared with PED but more perioperative major complications. Tandem treatment and coiling assistance may have poorer clinical outcomes but similar occlusion rates. Single- and multiple-stent treatments had similar outcomes.

Conclusion

FD treatment of PC aneurysms achieved favorable clinical outcomes and long-term aneurysm occlusion rates with acceptable perioperative complication rates, especially in dissecting and non-basilar artery aneurysms. There was no additional improvement in outcomes with coiling assistance, multi-stent application, or tandem treatment. Therefore, the use of PC aneurysms should be carefully considered.

Characteristics and evolution of cerebral aneurysms among adults living with HIV: A retrospective, longitudinal case series

OBJECTIVE

Previous research indicates an increased risk of cerebral aneurysm formation in adults living with human immunodeficiency virus (ALWH), however there are few longitudinal studies on the risk factors for and outcomes of cerebral aneurysms in this population. We aim to describe the characteristics and evolution of cerebral aneurysms in a large cohort of ALWH.

MATERIALS AND METHODS

A chart review was completed for all adults evaluated at an urban, safety-net U.S. hospital between January 1, 2000, and October 22, 2021, with history of both HIV and at least one cerebral aneurysm.

RESULTS

A total of 82 cerebral aneurysms were identified amongst 50 patients (52% female sex). Forty-six percent of patients with a nadir CD4 count less than 200 cells/mm³ (N=13) and 44% of patients with maximum viral load >10,000 copies/mL (N=18) developed new aneurysms or were found to have aneurysm growth over time compared with 29% of patients with a CD4 nadir above 200 cells/mm³ (N=21) and 22% of patients with maximum viral load </= 75 copies/mL (N=9). New aneurysms were found, or existing aneurysms grew in 67% of those not on antiretroviral therapy (ART) at time of aneurysm diagnosis (N=6), 38% of those with inconsistent ART use (N=8), and 21% of those with consistent ART (N=19).

CONCLUSIONS

Among ALWH, lower CD4 nadir, higher zenith viral load, and inconsistent ART use may contribute to aneurysm formation or growth. Further studies are needed to more thoroughly characterize the association between immunologic status and cerebral aneurysm formation.

Supraclinoid Internal Carotid Artery Dolichoectasia Causing Compression of the Prechiasmatic Optic Nerve

BACKGROUND AND IMPORTANCE

Intracranial arterial dolichoectasia (or dilatative arteriopathy) is characterized by abnormal elongation, tortuosity, or increase in diameter of at least one of the main cerebral vessels. Dolichoectasia can be found incidentally or can present with cranial neuropathies (including vision loss) or stroke. Here, we describe the presentation and open surgical treatment of a patient with dolichoectasia of the intracranial internal carotid artery (ICA) causing monocular vision loss.

CLINICAL PRESENTATION

A 73-year-old man presented with several months of progressive monocular vision loss and was found to have dolichoectasia of the supraclinoid ICA and subsequently underwent microsurgical decompression of the overlying affected optic nerve. The patient's postoperative convalescence was uncomplicated, and he had improvement in his right-sided monocular vision loss after surgery.

CONCLUSION

We present the case of a patient with dolichoectasia of the supraclinoid ICA causing compression of the optic nerve with resultant monocular vision loss. Timely microvascular decompression proves to be an effective technique for vision preservation in the setting of this rare pathologic entity.

Petrous Carotid to Upper Posterior Circulation Bypass for the Treatment of Basilar Trunk Aneurysm: A Novel High-Flow Intracranial-Intracranial Skull Base Bypass for Posterior Circulation

BACKGROUND

Basilar trunk aneurysms are the most surgically challenging, and the spectrum covers small fusiform to dolichoectatic aneurysms and may lead to rupture, brain ischemia, or direct brainstem compression. The current strategy remains cerebral revascularization coupled with aneurysm trapping. Available bypass options for upper posterior circulation (UPC) are based on (1) different flow volumes from diverse blood supplies and (2) distinct modulation purposes for cerebral revascularization; however, the potential compromise of eloquent perforators of the basilar trunk and the occurrence of fatal brainstem infarcts remain unacceptable.

OBJECTIVE

To innovate a high-flow intracranial-intracranial skull base bypass for posterior circulation to afford robust retrograde flow and shorten the graft length.

METHODS

We retrospectively reviewed our experience in the treatment of a patient with basilar trunk aneurysm and reported a novel bypass alternative supplied by petrous internal carotid artery to augment blood flow to the UPC by a pretemporal approach.

RESULTS

The postoperative course was uneventful, and there was no pons or midbrain ischemia or other complications. Postoperative computed tomography angiogram revealed the patency of bypass. There was no further development or rerupture observed during follow-up.

CONCLUSION

Petrous internal carotid artery as a donor site is a reliable bypass modality for UPC. This approach provides the utmost retrograde flow to alleviate the development of dissecting aneurysms, preserves eloquent perforators of the basilar trunk, maintains bypass patency, and shortens the graft course. Therefore, this novel therapeutic alternative could be beneficial for improving the prognosis of basilar trunk aneurysms.

Flow Redirection Endoluminal Device Flow Diverter Placement for Recurrent Dolichoectatic Vertebrobasilar Artery Aneurysm Treated with Multiple Low-Profile Visualized Intraluminal Support Stents: A Case Study

Objective

We report a case of dolichoectatic vertebrobasilar aneurysms treated with multiple low-profile visualized intraluminal support (LVIS) stents followed by flow redirection endoluminal device (FRED) flow diverter to prevent the growth of the thrombosed aneurysm.

Case Presentation

A 71-year-old man developed diplopia due to oculomotor nerve palsy after 11 years of follow-up for an enlarging thrombosed dolichoectatic vertebrobasilar artery aneurysm. He initially had a fusiform thrombosed aneurysm from the right vertebral artery to the basilar artery. This lesion was tortuous and strongly compressed the pons. A total of 11 LVISs were deployed from the right posterior cerebral artery to the right vertebral artery. Six months after surgery, there was no enlargement of the thrombosed aneurysm on MRI and the contrast leakage out of the stent was markedly reduced in DSA compared to immediately after surgery. One year and seven months after surgery, contrast leakage out of the stent was increased in DSA. The FRED was placed within the overlapped LVISs, and contrast leakage was somewhat reduced. After 2 years and 7 months from the initial treatment, the contrast leakage was still observed. However, there was no enlargement of the aneurysm and no complications related to treatments were observed.

Conclusion

Treatment with multiple LVIS stents followed by FRED flow diverter treatment for dolichoectatic vertebrobasilar aneurysms (DVAs) may be one of the treatment options for controlling the growth of thrombotic aneurysms without complications, but the long-term prognosis of this case is unclear, and careful follow-up is mandatory.

Flow diversion treatment for giant intracranial serpentine aneurysms

Background

Giant serpentine aneurysms (GSAs) are among the most complex and challenging type of intracranial aneurysms. Surgical clipping, bypass, or endovascular parent artery occlusion has been the main treatment of GSAs in the past. However, studies on flow diversion (FD) are limited. Therefore, we reported our experience with patients with GSAs treated with FD.

Methods

Patients with GSAs treated with FD from 2012 to 2020 in our single center were retrospectively reviewed. Angiographic outcomes were graded according to the O’Kelly–Marotta scale as complete occlusion (D), trace filling (C), entry remnant (B), or aneurysm filling (A). Clinical outcomes were assessed using the modified Rankin scale (mRS) score. We also collected the patients’ treatment details and perioperative complications.

Results

Thirteen patients with 14 aneurysms were included, including three in the anterior circulation and 11 in the posterior circulation. Grades B–D were found in 72.7% (8/11) of the GSAs. Good prognosis (mRS score, 0–2) was found in 66.7% (8/12) and 50.0% (6/12) of the patients at the 6-month and latest follow-up, respectively. Parent artery occlusion was found in three cases of GSAs. Five postoperative complications were observed, including two minor complications and three major complications.

Conclusion

Although reconstructive treatment with FD could be considered as one of the treatment strategies for patients with both anterior and posterior circulation GSAs, however, the risk of complications and parent artery occlusion should be considered.

Telescoping pipeline vantage embolization devices with shield technology for the treatment of a giant, symptomatic dolichoectatic basilar trunk aneurysm

Background:

Dolichoectatic basilar trunk aneurysms are exceedingly rare and carry a poor prognosis. Treatment strategies are often reserved for patients with severe and progressive symptoms.

Case Description:

A patient in their 40s with a dolichoectatic basilar trunk aneurysm developed significant progression of the lesion and neurologic decline, necessitating treatment. He underwent flow diversion utilizing multiple telescoping Pipeline Vantage Embolization Devices with Shield Technology for treatment. At 1-year follow-up, the aneurysm was stable in size and the patient remained at his neurologic baseline.

Conclusion:

This case illustrates the need for continued development of next-generation endovascular devices as these aneurysms have limited management options.

Analysis of Bending Degree of Basilar Artery Using Image Processing

The basilar artery, which is the core of the posterior circulation, supplies blood to the brainstem and cerebellum. When basilar artery blood circulation is impaired, several symptoms can occur. In addition, the bending of the basilar artery causes stroke and infarction. Therefore, an image processing method for analyzing the bending degree of the basilar artery is introduced herein. To analyze the bending degree, the coordinates of the center points of the basilar artery are extracted using image processing techniques such as Canny edge detection, the contour technique, and the distance conversion technique. An image reconstructed using the three-dimensional scatter plot function in MATLAB and vector plots is used to calculate the vectors for each central point of the basilar artery. Meanwhile, the angle of each central point is calculated by selecting the first central point where the basilar artery begins, the central point with the greatest bending degree, and the central point at which the branching ends. The greater the bending degree of the basilar artery is, the larger the magnitude of the vector in the bending direction. The obtained results are verified by experts in the field, and the proposed algorithm demonstrates good performance.

Symptomatic Vascular Compression of Brainstem May Be Managed Conservatively

Medulla compression from vertebral artery abnormality is a very rare occurrence with few cases present in the literature. It has been documented to present with a very wide spectrum of clinical symptomatology ranging from asymptomatic to full hemiplegia. There is currently no treatment algorithm in place to guide clinicians encountering such patients but treatments have historically involved major posterior compartment surgical interventions. This case outlined a patient evaluated for dizziness without any other neurological symptoms or signs, found to have abnormal dilatation, elongation, and tortuosity of the vertebral artery with resultant compression of the medulla oblongata. The patient was managed conservatively after discussion of surgical options. This report outlined an important consideration for management of medullar compression by vertebral artery based on symptom severity with the possibility of postponing surgical or endovascular interventions and opting for conservative management with an anti-platelet regimen, particularly in the short term.

Comparisons between cross-section and long-axis-section in the quantification of aneurysmal wall enhancement of fusiform intracranial aneurysms in identifying aneurysmal symptoms

Background

To investigate the quantification of aneurysmal wall enhancement (AWE) in fusiform intracranial aneurysms (FIAs) and to compare AWE parameters based on different sections of FIAs in identifying aneurysm symptoms.

Methods

Consecutive patients were prospectively recruited from February 2017 to November 2019. Aneurysm-related symptoms were defined as sentinel headache and oculomotor nerve palsy. All patients underwent high resolution magnetic resonance imaging (HR-MRI) protocol, including both pre and post-contrast imaging. CR_stalk (signal intensity of FIAs' wall divided by pituitary infundibulum) was evaluated both in the cross-section (CR_{stalk−cross}) and the long-axis section (CR_stalk−long) of FIAs. Aneurysm characteristics include the maximal diameter of the cross-section (D_max), the maximal length of the long-axis section (L_max), location, type, and mural thrombus. The performance of parameters for differentiating symptomatic and asymptomatic FIAs was obtained and compared by a receiver operating characteristic (ROC) curve.

Results

Forty-three FIAs were found in 43 patients. Eighteen (41.9%) patients who presented with aneurysmal symptoms were classified in the symptomatic group. In univariate analysis, male sex (P = 0.133), age (P = 0.013), FIAs type (P = 0.167), mural thrombus (P = 0.130), L_max (P = 0.066), CR_{stalk−cross} (P = 0.027), and CR_stalk−long (P = 0.055) tended to be associated with aneurysmal symptoms. In the cross-section model of multivariate analysis, male (P = 0.038), age (P = 0.018), and CR_{stalk−cross} (P = 0.048) were independently associated with aneurysmal symptoms. In the long-axis section model of multivariate analysis, male (P = 0.040), age (P = 0.010), CR_stalk−long (P = 0.046), and L_max (P = 0.019) were independently associated with aneurysmal symptoms. In the combination model of multivariate analysis, male (P = 0.027), age (P = 0.011), CR_{stalk−cross} (P = 0.030), and L_max (P = 0.020) were independently associated with aneurysmal symptoms. CR_{stalk−cross} has the highest accuracy in predicting aneurysmal symptoms (AUC = 0.701). The combination of CR_{stalk−cross} and L_max exhibited the highest performance in discriminating symptomatic from asymptomatic FIAs (AUC = 0.780).

Conclusion

Aneurysmal wall enhancement is associated with symptomatic FIAs. CR_{stalk−cross} and L_max were independent risk factors for aneurysmal symptoms. The combination of these two factors may improve the predictive performance of aneurysmal symptoms and may also help to stratify the instability of FIAs in future studies.

Quantification of aneurysm wall enhancement in intracranial fusiform aneurysms and related predictors based on high-resolution magnetic resonance imaging: a validation study

Background:

Aneurysm wall enhancement (AWE) in high-resolution magnetic resonance imaging (HR-MRI) has emerged as a new imaging biomarker of intracranial aneurysm instability.

Objective:

To determine a standard method of AWE quantification for predicting fusiform intracranial aneurysms (FIAs) stability by comparing the sensitivity of each parameter in identifying symptomatic FIAs. The predictors of AWE and FIA types were also identified.

Methods:

We retrospectively analyzed consecutive fusiform aneurysm patients who underwent HR-MRI from two centers. The aneurysm-to-pituitary stalk contrast ratio (CR_stalk), aneurysm enhancement ratio, and aneurysm enhancement index were extracted, and their sensitivities in discriminating aneurysm symptoms were compared using the receiver-operating characteristic curve. Morphological parameters of fusiform aneurysm were extracted based on 3D vessel model. Uni- and multivariate analyses of related predictors for AWE, CR_stalk, and FIA types were performed, respectively.

Results:

Overall, 117 patients (mean age, 53.3 ± 11.7 years; male, 75.2%) with 117 FIAs underwent HR-MRI were included. CR_stalk with the maximum signal intensity (CR_stalk-max) had the highest sensitivity in identifying symptomatic FIAs with an area under the curve value (0.697) and a cut-off value of 0.90. The independent predictors of AWE were aneurysm symptoms [(odds ratio) OR = 3.754, p = 0.003], aspirin use (OR = 0.248, p = 0.037), and the maximum diameter of the cross-section (OR = 1.171, p = 0.043). The independent predictors of CR_stalk-max were aneurysm symptoms (OR = 1.289, p = 0.003) and posterior circulation aneurysm (OR = 1.314, p = 0.001). Transitional-type showed higher rates of hypertension and mural thrombus over both dolichoectatic- and fusiform-type FIAs.

Conclusion:

CR_stalk-max may be the most reliable parameter to quantify AWE to distinguish symptomatic FIAs. It also has the potential to identify unstable FIAs. Several factors contribute to the complex pathophysiology of FIAs and need further validation in a larger cohort.

Anatomical effects on the relationship between brain arterial diameter and length: The Northern Manhattan Study

BACKGROUND AND PURPOSE

In patients with dolichoectasia, it is uncertain how dilatation and/or elongation relate to each other. We aimed to examine the correlation between arterial diameter and length within arteries and across the circle of Willis (COW).

METHODS

We included stroke-free participants in the Northern Manhattan Study who underwent magnetic resonance angiography. Intracranial artery diameters and lengths were obtained with semiautomated commercial software and were adjusted for head size. We first investigated the correlation between diameters and length using Pearson's correlation coefficient. We then built generalized linear models adjusted for demographics and risk factors.

RESULTS

Among 1210 participants included in the analysis (mean age 71 ± 9 years, 59% women, 65% Hispanic), a larger basilar artery (BA) diameter correlated with greater BA length (r = .3), and left and right middle cerebral artery (MCA) diameters correlated with one another (r = .4). Across the COW, BA diameter correlated with MCA diameters (r = .3 for both). In adjusted analyses, MCA diameters were associated with larger posterior circulation diameters (β = 0.07), MCA and BA lengths (β = 0.003 and β = 0.002, respectively), presence of fetal posterior cerebral artery (PCA), (β = 0.11), and a complete COW (β = -0.02). Similarly, BA length was associated with a fetal PCA (β = 1.1), and BA diameter was associated with anterior circulation diameters (β = 0.15) and presence of fetal PCA (β = -0.4).

CONCLUSIONS

COW configuration should be considered when using arterial diameter cutoffs to define dolichoectasia. Further studies are needed to discern whether arterial diameter or length best identify individuals at risk of vascular events attributable to dolichoectasia.

Dolichoectasia: a brain arterial disease with an elusive treatment

INTRODUCTION

Dolichoectasia is a form of brain large artery disease associated with a high risk of mortality and morbidity. Progressive enlargement of arterial size is a predictor of mortality, but there are no specific treatments for arresting or slowing down dilatation. Additionally, dilated brain arteries can cause flow stagnation, which can trigger thrombosis and cause stroke. Pathology and genetic studies indicate a possible role for increased matrix metalloproteinase activation in arterial dilatation and thus in the pathophysiology of dolichoectasia. Therefore, therapeutic interventions aimed at slowing down arterial dilatation and preventing thrombosis could hypothetically play a role in treating patients with dolichoectasia.

METHODS

We present four patients with dolichoectasia that exemplify therapeutic challenges worth discussing in the context of the current literature. Two patients were treated off-label with doxycycline (based on its antiMMP properties) and with apixaban, one patient was put on warfarin and later switched to aspirin, and the fourth patient underwent endovascular treatment.

RESULTS

We report four cases, all men 50 years or older. Of the two patients treated with doxycycline, we noted a slowdown of the basilar artery (BA) growth, but the BA continued to grow in the other patient. Of the two patients who received apixaban, none had a subsequent stroke in 5 and 4 years of follow-up, respectively. One patient was admitted with a fatal BA thrombosis and rupture, and pathological examination of the brain arteries demonstrated advanced arterial wall degeneration but no atherosclerosis.

DISCUSSION

These cases exemplify the challenges of treating people with dolichoectasia and highlight the need for better evidence regarding the best possible treatment for this population.

Endovascular occlusion of giant serpentine aneurysm: A case report and literature review

Giant serpentine aneurysms (GSAs) are a rare subgroup of intracranial aneurysms. Separate inflow and outflow flow due to intraluminal thrombosis is the most distinguishing feature of GSAs. In treating these lesions, surgical clipping and ligation were the main treatments in the past, but bypass for revascularisation and endovascular therapies (EVTs) for deconstructive purposes are more prominent today. A 51-years-old male patient presented with headache and mild right hemiparesis. He had a GSA arising from the left fetal type posterior cerebral artery (fPCA) that was out of follow-up for six years. Radiological images revealed midline shifting and mesencephalon compression. We performed endovascular parent artery coil occlusion. The symptoms of the patient improved at the first-month follow-up. Even if there is a mass effect in GSAs, deconstructive EVT is a safe and feasible method for managing these lesions.

[Diagnosis and treatment of non-saccular vertebrobasilar aneurysms]

OBJECTIVE

To systematize the data on diagnosis and treatment of non-saccular vertebrobasilar aneurysms.

MATERIAL AND METHODS

We have analyzed modern and fundamental studies in the PubMed database for the period 1969-2020. The following keywords were used: non-saccular aneurysm, dolichoectasia, vertebrobasilar pool. Fifty-nine studies including 1 meta-analysis, 9 case reports, 24 reviews and 25 original articles were selected.

RESULTS

Analysis of literature data indicates various unresolved problems associated with difficult diagnosis and choice of treatment that results high rates of disability and mortality.

CONCLUSION

Data on anatomical features of non-saccular aneurysms, such as presence or absence of perforating arteries within the affected arterial segment, analysis of electrophysiological changes following brainstem compression by aneurysm can serve as factors that will improve treatment outcomes in these patients.

[Unfavorable outcome of giant vertebral artery aneurysm. Clinical case and literature review]

OBJECTIVE

To demonstrate the unfavorable natural course and prognosis of giant vertebral artery aneurysm, to analyze the literature, and to conduct a postmortem histopathological study of the features of this disease.

Intracranial Fusiform and Circumferential Aneurysms of the Main Trunk: Therapeutic Dilemmas and Prospects

Intracranial fusiform and circumferential aneurysms (IFCAs), especially those located on the main trunk, are uncommon and difficult to manage. Currently, literature focused on IFCAs on the main trunk of cerebral arteries is lacking. The treatment of IFCAs is still under debate. Therefore, in this review, we further explore the treatment of this complicated entity. In addition, we also present some interesting cases. Based on the literature review and our experience, we found that IFCAs are often located in the vertebrobasilar system and that ruptured or large symptomatic IFCAs are associated with increased mortality and higher rebleeding rates. The treatment strategies for IFCAs can be classified as deconstructive and reconstructive methods via open surgery and/or endovascular treatment (EVT). Currently, EVT is a popular method and the main therapeutic choice. In particular, flow diversion has revolutionized the treatment of IFCAs. Parent artery occlusion (PAO) with or without revascularization may still be considered a suitable choice. Complex IFCAs that cannot be resolved by EVT can also be treated via open surgery with or without extracranial–intracranial bypass. Targeted embolization for the weak points of IFCAs is a temporary or palliative choice that is rarely used. In summary, despite complications, both surgical treatment and EVT are effective options for appropriately selected cases. Due to the development of endovascular implants, EVT will have better prospects in the future.

In Situ Side-to-Side Pericallosal-Pericallosal Artery and Callosomarginal-Callosomarginal Artery Bypasses for Complex Distal Anterior Cerebral Artery Aneurysms: A Technical Note

BACKGROUND

Despite surgical and endovascular technical improvements over the last decades, the treatment of complex aneurysms of the distal anterior cerebral artery (ACA) is very challenging for both vascular neurosurgeons and interventional neuroradiologists. Furthermore, the interpersonal anatomic variability requires, most of the time, a tailored planning.

OBJECTIVE

To describe a novel technique of bypasses in the territory of ACA to protect the brain territory distal to the aneurysm.

METHODS

A 53-yr-old male with a large complex fusiform aneurysm of the left distal A2 segment of the ACA, involving the origin of the callosomarginal and pericallosal arteries, was judged not suitable for a single procedure (endovascular or neurosurgical). Two side-to-side bypasses were performed in a single surgery to connect the pericallosal and callosomarginal arteries of both sides, distally to the aneurysm. Subsequently, an endovascular embolization of the aneurysm was achieved with coils.

RESULTS

The patency of the microanastomoses, performed in the anterior interhemispheric fissure, was positively evaluated intraoperatively with indocyanine green and fluorescein videoangiography. The aneurysm sac, together with proximal A2 segment, was completely occluded with platinum coils. At the last follow-up, computed tomography angiography confirmed the patency of both bypasses, without any sign of aneurysm recanalization. The patients never complained of any focal neurological deficits or worsening of clinical status.

CONCLUSION

We present an elegant and innovative solution to completely protect the distal ACA territory in cases of complex aneurysm involving the origin of both callosomarginal and pericallosal arteries.

Giant Fusiform and Dolichoectatic Aneurysms of the Basilar Trunk and Vertebrobasilar Junction-Clinicopathological and Surgical Outcome

BACKGROUND

Giant fusiform and dolichoectatic aneurysms of the basilar trunk and vertebrobasilar junction (BTVBJ-GFDA) are extremely difficult to treat.

OBJECTIVE

To evaluate factors influencing survival and outcome of BTVBJ-GFDA by performing a retrospective multicenter cohort study.

METHODS

A total of 32 patients with BTVBJ-GFDA were included in this study. Clinicopathological characteristics, treatment measures, and outcomes were collected from medical records and imaging studies. Autopsy and histological findings of the aneurysm and adjacent brain tissue were also obtained in 9 cases.

RESULTS

A total of 11 patients did not undergo surgery, of whom 10 died; 3 from progressive brainstem compression, 4 from subarachnoid hemorrhage, 2 from brainstem infarction, and 1 from associated atherosclerotic disease. The remaining 21 patients underwent a surgical treatment, consisting of immediately proximal parent artery occlusion, remotely proximal parent artery occlusion, clip reconstruction, and distal bypass and achieved significantly longer overall survival compared with those who received conservative therapy (adjusted hazard ratio 1.508, 95% CI 1.058-2.148, P = .02). Histological examination of the aneurysms demonstrated staged clots, open lumen, and intrathrombotic channels with endothelial lining. The patients younger than 45 yr of age showed statistically longer survival than those equal and older than 45 yr (P = .03).

CONCLUSION

Surgical intervention achieved greater survival than conservative management in BTVBJ-GFDA. Narrow ideal treatment window of the blood flow within the aneurysm to maintain sufficient but not excess supply should be targeted based on the hemodynamics of both the posterior communicating arteries and perforating vessel collaterals.

Insights into the pathogenesis of cerebral fusiform aneurysms: high-resolution MRI and computational analysis

BACKGROUND

Intracranial fusiform aneurysms are complex and poorly characterized vascular lesions. High-resolution magnetic resonance imaging (HR-MRI) and computational morphological analysis may be used to characterize cerebral fusiform aneurysms.

OBJECTIVE

To use advanced imaging and computational analysis to understand the unique pathophysiology, and determine possible underlying mechanisms of instability of cerebral fusiform aneurysms.

METHODS

Patients with unruptured intracranial aneurysms prospectively underwent imaging with 3T HR-MRI at diagnosis. Aneurysmal wall enhancement was objectively quantified using signal intensity after normalization of the contrast ratio (CR) with the pituitary stalk. Enhancement between saccular and fusiform aneurysms was compared, as well as enhancement characteristics of fusiform aneurysms. The presence of microhemorrhages in fusiform aneurysms was determined with quantitative susceptibility mapping (QSM). Three distinct types of fusiform aneurysms were analyzed with computational fluid dynamics (CFD) and finite element analysis (FEA).

RESULTS

A total of 130 patients with 160 aneurysms underwent HR-MRI. 136 aneurysms were saccular and 24 were fusiform. Fusiform aneurysms had a significantly higher CR and diameter than saccular aneurysms. Enhancing fusiform aneurysms exhibited more enhancement of reference vessels than non-enhancing fusiform aneurysms. Ten fusiform aneurysms underwent QSM analysis, and five aneurysms showed microhemorrhages. Microhemorrhage-positive aneurysms had a larger volume, diameter, and greater enhancement than aneurysms without microhemorrhage. Three types of fusiform aneurysms exhibited different CFD and FEA patterns.

CONCLUSION

Fusiform aneurysms exhibited more contrast enhancement than saccular aneurysms. Enhancing fusiform aneurysms had larger volume and diameter, more enhancement of reference vessels, and more often exhibited microhemorrhage than non-enhancing aneurysms. CFD and FEA suggest that various pathophysiological processes determine the formation and growth of fusiform aneurysms.

Combined Microsurgical, Endovascular, and Endoscopic Approach to the Treatment of a Giant Vertebrobasilar Aneurysm

BACKGROUND

Dolichoectasia is defined as elongation and dilatation of a blood vessel. In the intracranial circulation, the basilar artery is affected in 80% of cases. These are challenging lesions with an aggressive natural history, and treatment carries a relatively high rate of morbidity and mortality. We describe a case of multimodal treatment including endovascular, open microsurgical, and endoscopic endonasal approach (EEA) for management.

OBJECTIVE

To describe the technical nuance of the addition of the EEA for management of posterior circulation dolichoectasia.

METHODS

A 44-yr-old Hispanic woman with a 2-mo history of progressive headaches, gait disturbance, and lower cranial nerve dysfunction presented with acute neurologic decline. MRI demonstrated a dolichoectatic vertebrobasilar system with a giant 4.5-cm fusiform basilar aneurysm.

RESULTS

She underwent concomitant endovascular bilateral vertebral artery sacrifice with suction decompression and trapping by clip ligation distal to the lesion. Postoperatively, she developed symptomatic pontine compression. She was then taken for a transclival EEA for intra-aneurysmal thrombectomy. Thereafter, she made a significant functional recovery.

CONCLUSION

The addition of endoscopic reconstruction to the treatment of a dolichoectatic basilar aneurysm is an operative nuance that can be employed in treating these highly morbid lesions. This case describing a multimodal treatment paradigm including EEA reconstruction can serve as an example for the future of treatment select cases of dolichoectasia of the vertebrobasilar complex.

Flow diversion of fusiform intracranial aneurysms

Fusiform aneurysms are less common than saccular aneurysms, but have higher associated mortality and rebleeding rates. Recently, flow diversion has emerged as a possible treatment option. The purpose of this study was to determine the safety and efficacy of the Pipeline Embolization Device (PED) for the treatment of ruptured and unruptured fusiform aneurysms. This was a retrospective analysis of patients with fusiform intracranial aneurysms treated with a PED at a quaternary care center between January 2012 and September 2019. Occlusion rates, neurologic morbidity/mortality, and other clinical variables were analyzed. Twenty-nine patients with 30 fusiform aneurysms were treated with a PED. Sixteen aneurysms (53%) were located in the anterior circulation and 14 aneurysms (47%) were in the posterior circulation. The mean maximal diameter of the aneurysms was 10.1 ± 5.6 mm (range 2.3-25 mm). Angiographic and clinical follow-up were available for 28 aneurysms (93%). The median follow-up was 17.4 months (IQR 4.8 to 28 months) and occlusion rates were graded according to the O'Kelly-Marotta (OKM) scale. Of patients with DSA follow-up, 15 aneurysms (60%) were completely occluded (OKM D) and 19 aneurysms (76%) had a favorable occlusion result (OKM C1-3 and D). The overall complication rate was 26.7% with a neurological morbidity rate of 6.7% and neurological mortality rate of 3.4%. Flow diversion can be an effective treatment for both ruptured and unruptured fusiform aneurysms. Nevertheless, complete occlusion rates are lower than for saccular aneurysms. Therefore, flow diversion should be considered only if other more direct treatment options, such as clipping or stent/coiling are not applicable. Flow diversion should be used cautiously in patients presenting with rupture.

Fusiform aneurysms of the vertebrobasilar complex: a single-center series

BACKGROUND

Fusiform vertebrobasilar aneurysms (FVBAs) may exhibit a disastrous clinical course. Due to their rare occurrence, evidence concerning optimal management is lackluster.

OBJECTIVE

To describe the epidemiology, clinical features and treatment outcomes of a consecutive series of patients admitted to our institution.

METHODS

We retrospectively evaluated patient charts with respect to clinical presentation, treatment procedures, and the outcomes of all patients diagnosed with an FVBA, which were seen at our institution between March 2006 and February 2017.

RESULTS

Forty-five consecutive patients were analyzed. Follow-up was available for 39 patients (86.7%) with a median duration of 28.8 months. Seventeen patients (37.7%) were asymptomatic, 14 patients (31.1%) presented with brainstem ischemia, 8 patients (17.8%) with supratentorial ischemia, and 3 (6.7%) patients with brain stem compression. Aneurysm rupture occurred in 3 patients upon presentation (6.7%). Initially, 19 patients (42.2%) were significantly disabled with Modified Rankin Scale (mRS) scores ≥ 3. Twelve patients (26.7%) underwent invasive treatment: endovascular therapy in 9 cases and surgical treatment in 3 cases. Thirty-three patients received conservative treatment. During follow-up, 6 events (66.7%) of severe disability or death (mRS 4-6) occurred in the endovascular group versus 1 event (33%) in the surgical group versus 19 events (63.3%) among conservatively treated aneurysms. Deterioration was significantly more frequent in patients with symptomatic aneurysms (p = 0.030).

CONCLUSION

Patients harboring an FVBA frequently present with disabling symptoms caused by various pathomechanisms. The natural history is aggressive, mostly for initially symptomatic aneurysms, and periprocedural morbidity of surgical or endovascular treatment remains substantial.

Flow Diversion for the Treatment of Petrous Internal Carotid Artery Aneurysms

Petrous internal carotid artery (ICA) aneurysms are rare and pose a unique management dilemma. They are most commonly fusiform. They are difficult to treat surgically and typically not amenable to selective aneurysmal obliteration. The advent of flow diverters, such as the Pipeline endovascular device, has offered a new approach to these historically challenging lesions. The unique utility of flow diversion in treatment of petrous ICA aneurysms is reviewed and discussed.

Characteristics and Clinical Course of Fusiform Middle Cerebral Artery Aneurysms According to Location, Size, and Configuration

OBJECTIVE

To analyze the angiographic features and clinical course, including treatment outcomes and the natural course, of fusiform middle cerebral artery aneurysms (FMCAAs) according to their location, size, and configuration.

METHODS

We reviewed the literature on adult cases of FMCAAs published from 1980 to 2018; from 25 papers, 112 FMCAA cases, for which the location, size, and configuration could be identified, were included in this study. Additionally, 33 FMCAA cases in our hospital were included, from which 16 were assigned to the observation group. Thus, a total of 145 adult FMCAA cases were included. We classified the FMCAAs according to their location (l-type 1, beginning from prebifurcation; l-type 2, beginning from bifurcation; l-type 3, beginning from postbifurcation), size (small, <10 mm; large, ≥10 mm; giant, ≥25 mm), and configuration (c-type 1, classic dissecting aneurysm; c-type 2, segmental ectasia; c-type 3, dolichoectatic dissecting aneurysm).

RESULTS

The c-type 3 was more commonly diagnosed with ischemic symptoms (31.8%) than hemorrhage (13.6%), while 40.9% were found accidentally. In contrast, c-type 2 was more commonly diagnosed with hemorrhagic symptoms (14.9%) than ischemic symptoms (10.6%), and 72.3% were accidentally discovered. According to location, ischemic symptoms and hemorrhage were the most frequent symptoms in l-type 1 (28.6%) and l-type 3 (34.6%), respectively. Most of l-type 2 FMCAAs were found incidentally (68.4%). Based on the size of FMCAAs, only 11.1% of small aneurysms were found to be hemorrhagic, while 18.9% and 26.0% of large and giant aneurysms were hemorrhagic, respectively. Although four aneurysms of the 16 FMCAAs in the observation group increased in size and one aneurysm decreased in size during the observation period, no rupture was seen in any case and there were no significant predictors of aneurysm enlargement. Of 104 FMCAAs treated, 14 cases (13.5%) were aggravated than before surgery and all the aggravated cases were l-type 1.

CONCLUSION

While ischemic symptoms occurred more frequently in l-type 1 and c-type 3, hemorrhagic rather than ischemic symptoms occurred more frequently in l-type 3 and c-type 2. In case of l-type 1 FMCAAs, more caution is required in determining the treatment due to the relatively high complication rate.

A 5-Year Follow-up of Intracranial Arterial Dolichoectasia: A Case Report and Review of Literature

A patient with multiple dolichoectasia of the intracranial cerebral artery was followed sequentially with clinical and radiological progression of disease in the past 5 years. The patient was treated in multiple stages in the past 5 years with the endovascular and microsurgical clipping method. The maximum diameter of each major intracranial artery segment was recorded and compared in the follow-up year. The progression in size of the dolichoectatic segment was observed in spite of surgical intervention. In review diagnostic criteria, etiopathogenesis and treatment options have been discussed.

Fusiform vertebral artery aneurysms involving the posterior inferior cerebellar artery origin associated with the sole angiographic anterior spinal artery origin: technical case report and treatment paradigm proposal

Fusiform aneurysms of the vertebral artery (VA) involving the posterior inferior cerebellar artery (PICA) origin are uncommon and challenging. The anterior spinal artery (ASA) commonly originates from a unilateral ramus just distal to the PICA. Occlusion of an unpaired ASA can result in bilateral medial medullary syndrome. The authors propose a treatment paradigm for ASA preservation based on the artery's proximity to fusiform VA aneurysms, and they present 3 representative cases. In the first case, they performed a V3-PICA bypass using an interposition graft and then performed endovascular coil embolization of the parent VA. A complete occlusion of the aneurysm and VA was complicated by ASA thrombosis. The subsequent cases were treated with PICA-PICA bypass and subsequent endovascular embolization of the VA. Filling of the sole angiographic ASA remote from the aneurysm was preserved in both cases. The anatomy of the ASA is the most critical determinant of treatment recommendations for fusiform VA aneurysms involving PICA. When the ASA originates from the aneurysm, proximal occlusion with or without a PICA bypass is suggested. In cases in which the ASA is removed from the aneurysm, the authors recommend revascularization followed by endovascular sacrifice. When the aneurysm is immediately adjacent to the ASA, revascularization and open trapping should be considered.

A refined experimental model of fusiform aneurysms in a rabbit carotid artery

OBJECTIVE

Reliable animal models are an important aspect of translational research, especially for relatively uncommon clinical entities such as fusiform aneurysms. While several animal models exist, very few are tailored to cerebral fusiform aneurysms, which have unique attributes compared to abdominal fusiform aneurysms. The authors aimed to build from previous models to create a cerebral fusiform aneurysm model that is simple to use and reliable.

METHODS

Twelve female New Zealand White rabbits were assigned to 3 groups: group E, elastase only; group C, CaCl2 only; group EC, elastase + CaCl2. All rabbits underwent surgical exposure of the right common carotid artery (CCA) and 20 minutes of peri-carotid incubation with their respective chemicals. Angiography was performed 6 weeks later for arterial dilation measurements, with 50% increase in diameter being defined as fusiform aneurysm formation. The arterial segments, along with the contralateral CCAs, were harvested and assessed histologically for wall component measurements and elastin semiquantification. A separate rabbit underwent aneurysm creation per the group EC protocol and was treated with an endovascular flow-diversion device.

RESULTS

All of the group EC rabbits developed fusiform aneurysms (mean dilation of 88%), while none of the group E or group C rabbits developed aneurysms (p = 0.001). Histological analysis revealed increased internal elastic lamina fragmentation in the group EC aneurysms, which also had less tunica intima hyperplasia. All aneurysms exhibited thinning of the tunica media and reduction in elastin content. The use of an endovascular flow-diverting stent was successful, with complete parent vessel remodeling, as expected, 4 weeks after deployment.

CONCLUSIONS

The peri-arterial application of combined elastase and CaCl2 to the CCA appears sufficient to reliably produce fusiform aneurysms after 6 weeks. Exposure to elastase or CaCl2 individually appears insufficient, despite the observed histological changes to the arterial wall. The proposed fusiform aneurysm model is able to accommodate endovascular devices, simulating the tortuous pathway experienced in using such devices in human cerebral aneurysms and thus is a satisfactory model to use in translational research.

Wall enhancement of intracranial saccular and fusiform aneurysms may differ in intensity and extension: a pilot study using 7-T high-resolution black-blood MRI

PURPOSE

To evaluate and compare wall enhancement patterns in saccular and fusiform intracranial aneurysms using high-resolution black-blood MRI at 7 T.

METHODS

Thirty-one patients with 32 unruptured intracranial aneurysms (21 saccular and 11 fusiform) underwent 7-T black-blood MRI. Aneurysm wall enhancement (AWE) was categorized as follows: no wall enhancement (NWE), focal wall enhancement (FWE), and uniform wall enhancement (UWE). The degree of enhancement was scored as follows: 0 (no enhancement), 1 (signal intensity (SI) of the aneurysm wall less than that of the pituitary infundibulum), and 2 (equal to that of the pituitary infundibulum). The chi-squared test was used to compare the AWE pattern and degree between saccular and fusiform aneurysms.

RESULTS

In saccular aneurysms, 12/21 (57%) enhanced. Of these, 9 showed FWE (5 grade 1 and 4 grade 2), and 3 showed UWE (2 grade 1 and 1 grade 2). In fusiform aneurysms, 11/11 (100%) enhanced. Of these, 1 showed FWE and 10 showed UWE. All fusiform aneurysms had grade-2 enhancement. Fusiform aneurysms had more extensive and higher SI AWE than saccular aneurysms (p < 0.01) despite having a similar size (6.9 ± 3.0 mm vs. 8.0 ± 2.9, p = 0.23). For saccular aneurysm, larger aneurysm size was correlated with higher degree of enhancement with Pearson's r = 0.64 (p = 0.002).

CONCLUSION

Intracranial fusiform aneurysms had enhancement of higher SI and that covered a more extensive area than saccular aneurysms, which might indicate differences in vessel wall pathology.

KEY POINTS

• Intracranial aneurysm wall enhancement can be reliably characterized by 7-T black-blood MRI. • AWE in intracranial fusiform aneurysms presents over a larger surface area and with greater signal intensity as compared with that in saccular aneurysms, which might indicate differences in pathology. • Stronger signal intensity of AWE correlates with the aneurysm size in saccular aneurysms.

The future of open vascular neurosurgery: perspectives on cavernous malformations, AVMs, and bypasses for complex aneurysms

Despite the erosion of microsurgical case volume because of advances in endovascular and radiosurgical therapies, indications remain for open resection of pathology and highly technical vascular repairs. Treatment risk, efficacy, and durability make open microsurgery a preferred option for cerebral cavernous malformations, arteriovenous malformations (AVMs), and many aneurysms. In this paper, a 21-year experience with 7348 cases was reviewed to identify trends in microsurgical management. Brainstem cavernous malformations (227 cases), once considered inoperable and managed conservatively, are now resected in increasing numbers through elegant skull base approaches and newly defined safe entry zones, demonstrating that microsurgical techniques can be applied in ways that generate entirely new areas of practice. Despite excellent results with microsurgery for low-grade AVMs, brain AVM management (836 cases) is being challenged by endovascular embolization and radiosurgery, as well as by randomized trials that show superior results with medical management. Reviews of ARUBA-eligible AVM patients treated at high-volume centers have demonstrated that open microsurgery with AVM resection is still better than many new techniques and less invasive approaches that are occlusive or obliterative. Although the volume of open aneurysm surgery is declining (4479 cases), complex aneurysms still require open microsurgery, often with bypass techniques. Intracranial arterial reconstructions with reimplantations, reanastomoses, in situ bypasses, and intracranial interpositional bypasses (third-generation bypasses) augment conventional extracranial-intracranial techniques (first- and second-generation bypasses) and generate innovative bypasses in deep locations, such as for anterior inferior cerebellar artery aneurysms. When conventional combinations of anastomoses and suturing techniques are reshuffled, a fourth generation of bypasses results, with eight new types of bypasses. Type 4A bypasses use in situ suturing techniques within the conventional anastomosis, whereas type 4B bypasses maintain the basic construct of reimplantations or reanastomoses but use an unconventional anastomosis. Bypass surgery (605 cases) demonstrates that open microsurgery will continue to evolve. The best neurosurgeons will be needed to tackle the complex lesions that cannot be managed with other modalities. Becoming an open vascular neurosurgeon will be intensely competitive. The microvascular practice of the future will require subspecialization, collaborative team effort, an academic medical center, regional prominence, and a large catchment population, as well as a health system that funnels patients from hospital networks outside the region. Dexterity and meticulous application of microsurgical technique will remain the fundamental skills of the open vascular neurosurgeon.