Giant basilar bifurcation aneurysm presenting as a third ventricular mass with unilateral obstructive hydrocephalus: case report

Developing an in vitro validated 3D in silico internal carotid artery sidewall aneurysm model

Introduction: Direct quantification of hemodynamic factors applied to a cerebral aneurysm (CA) remains inaccessible due to the lack of technologies to measure the flow field within an aneurysm precisely. This study aimed to develop an in vitro validated 3D in silico patient-specific internal carotid artery sidewall aneurysm (ICASA) model which can be used to investigate hemodynamic factors on the CA pathophysiology. Methods: The validated ICASA model was developed by quantifying and comparing the flow field using particle image velocimetry (PIV) measurements and computational fluid dynamics (CFD) simulations. Specifically, the flow field characteristics, i.e., blood flowrates, normalized velocity profiles, flow streamlines, and vortex locations, have been compared at representative time instants in a cardiac pulsatile period in two designated regions of the ICASA model, respectively. One region is in the internal carotid artery (ICA) inlet close to the aneurysm sac, the other is across the middle of the aneurysmal sac. Results and Discussion: The results indicated that the developed computational fluid dynamics model presents good agreements with the results from the parallel particle image velocimetry and flowrate measurements, with relative differences smaller than 0.33% in volumetric flow rate in the ICA and relative errors smaller than 9.52% in averaged velocities in the complex aneurysmal sac. However, small differences between CFD and PIV in the near wall regions were observed due to the factors of slight differences in the 3D printed model, light reflection and refraction near arterial walls, and flow waveform uncertainties. The validated model not only can be further employed to investigate hemodynamic factors on the cerebral aneurysm pathophysiology statistically, but also provides a typical model and guidance for other professionals to evaluate the hemodynamic effects on cerebral aneurysms.

Effects of Pulsatile Flow Rate and Shunt Ratio in Bifurcated Distal Arteries on Hemodynamic Characteristics Involved in Two Patient-Specific Internal Carotid Artery Sidewall Aneurysms: A Numerical Study

The pulsatile flow rate (PFR) in the cerebral artery system and shunt ratios in bifurcated arteries are two patient-specific parameters that may affect the hemodynamic characteristics in the pathobiology of cerebral aneurysms, which needs to be identified comprehensively. Accordingly, a systematic study was employed to study the effects of pulsatile flow rate (i.e., PFR−I, PFR−II, and PFR−III) and shunt ratio (i.e., 75:25 and 64:36) in bifurcated distal arteries, and transient cardiac pulsatile waveform on hemodynamic patterns in two internal carotid artery sidewall aneurysm models using computational fluid dynamics (CFD) modeling. Numerical results indicate that larger PFRs can cause higher wall shear stress (WSS) in some local regions of the aneurysmal dome that may increase the probability of small/secondary aneurysm generation than under smaller PFRs. The low WSS and relatively high oscillatory shear index (OSI) could appear under a smaller PFR, increasing the potential risk of aneurysmal sac growth and rupture. However, the variances in PFRs and bifurcated shunt ratios have rare impacts on the time-average pressure (TAP) distributions on the aneurysmal sac, although a higher PFR can contribute more to the pressure increase in the ICASA−1 dome due to the relatively stronger impingement by the redirected bloodstream than in ICASA−2. CFD simulations also show that the variances of shunt ratios in bifurcated distal arteries have rare impacts on the hemodynamic characteristics in the sacs, mainly because the bifurcated location is not close enough to the sac in present models. Furthermore, it has been found that the vortex location plays a major role in the temporal and spatial distribution of the WSS on the luminal wall, varying significantly with the cardiac period.

Koester S, Santa Maria PE, Von Zuben D, Batista S, Schiavini HC, Landeiro JA. A Giant Internal Carotid Bifurcation Aneurysm as a Rare and Dangerous Differential Diagnosis of a Craniopharyngioma

Craniopharyngiomas are supra/parasellar lesions that often present with general, unspecific symptoms. Similarly, internal carotid artery (ICA) bifurcation giant aneurysms may also produce calcified, heterogeneous, parasellar expansive lesions, posing a relevant differential diagnosis due to their inherently different surgical strategies and risks. We report the case of a 54-year-old female presenting with progressive disorientation and apathetic behavior. CT and MRI reports described a suprasellar heterogenous mass with calcifications associated with an adjacent, laterally located fluid collection suggestive of a craniopharyngioma. During the surgical procedure, perfuse and unexplained arterial bleeding ensued, prompting the surgical team to review a previous contrast-enhanced CT scan. Careful inspection revealed an image suggestive of vascular pathology, with an area of continuous hyperdensity along the right ICA bifurcation. The Sylvian fissure was dissected, and an aneurysmal neck was encountered and successfully clipped. Giant intracranial aneurysms are rare but essential differential diagnoses to be considered during the workup and surgical approach toward parasellar mass lesions. This case illustrates the importance of performing a CT angiogram (CTA) for skull base lesions, even when the size is more suggestive of tumor pathology.

Trans-lateral ventricular approach for surgical treatment of a high located basilar apex aneurysm: report of a rare presentation of the disease and surgical technique

Surgical management of basilar apex aneurysms is considered among the most technically challenging procedures and high located basilar apex makes the procedure more challenging. Pterional trans-sylvian (with or without orbitozygomatic extension) and subtemporal are the most commonly used approaches, however, it is sometimes difficult or impossible to access a high-positioned aneurysm of basilar bifurcation without excessive retraction of brain and neurovascular structures. We are reporting a 65-year-old woman presented with chronic hydrocephalus secondary to a high-located basilar apex aneurysm surgically clipped through trans-frontal trans-ventricular trans-choroidal approach. We described anatomical details for selecting this approach and surgical steps during the procedure.

Delayed extensive brain edema caused by the growth of a giant basilar apex aneurysm treated with basilar artery obliteration: a case report

Background

Partially thrombosed giant aneurysms at the basilar apex (BA) artery are challenging lesions with a poor prognosis if left untreated. Here we describe a rare case of extensive brain edema after growth of a surgically treated and thrombosed giant basilar apex aneurysm.

Case presentation

We performed a proximal surgical basilar artery occlusion on a 64-year-old female with a partially thrombosed giant BA aneurysm. MRI showed no ischemic lesions but showed marked edema adjacent to the aneurysm. She had a good recovery, but 3 months after surgical occlusion, her gait deteriorated together with urinary incontinence and worsening right hemiparesis. MRI showed that the aneurysm had grown and developed intramural hemorrhage, which caused extensive brain edema and obstructive hydrocephalus. She was treated by a ventriculoperitoneal shunt placement. Follow-up MRI showed progressive brain edema resolution, complete thrombosis of the lumen and shrinkage of the aneurysm. At 5 years follow-up the patient had an excellent functional outcome.

Conclusions

Delayed growth of a surgically treated and thrombosed giant aneurysm from wall dissection demonstrates that discontinuity with the initial parent artery does not always prevent progressive enlargement. The development of transmural vascular connections between the intraluminal thrombus and adventitial neovascularization by the vasa vasorum on the apex of the BA seems to be a key event in delayed aneurysm growth. Extensive brain edema might translate an inflammatory edematous reaction to an abrupt enlargement of the aneurysm.

Rupture of Intradural Giant Aneurysms: The Mode of Treatment, Anatomical, and Mechanical Factors

OBJECTIVE

Aneurysm rupture is often a fatal complication of giant intradural aneurysm (GIA) treatments. The purpose of this study was to review aneurysm rupture in GIA treatment.

MATERIALS AND METHODS

We performed a systematic review on aneurysm rupture related to GIA treatment. For each reported case, we collected the following information: aneurysm location, size and rupture status, the mode of treatment, timing of the hemorrhage, anatomical, and hemodynamic factors.

RESULTS

We identified 56 aneurysm ruptures related to treatment in 38 published studies. Of the nine intraoperative ruptures, eight occurred during endovascular procedures and one in surgical treatment. Of the 47 delayed ruptures, 72.3% occurred within 2 weeks. The prognosis of intraoperative and delayed ruptures was poor, with 83.9% experiencing death. Of these aneurysms, 75% were initially unruptured. Of the delayed ruptured aneurysms, 21.3% had prior surgical treatment, 74.4% had prior endovascular treatment, and 4.3% had prior combined surgical and endovascular treatments. Vertebrobasilar artery (VBA) location was significantly associated with aneurysm rupture after treatment, occurring at 57.2%. Flow diverter (FD) treatment seemed to elevate the delayed rupture proportion of giant paraclinoid internal carotid artery (ICA) aneurysms from 22.0% to 42.9%. FD treatment did not lower the rupture risk of giant VBA aneurysms and the corresponding death rate.

CONCLUSION

Intraoperative and delayed aneurysm ruptures were the most challenging in endovascular treatment of GIAs. Giant VBA aneurysm had the highest rupture risk after treatment. FD seemed to elevate the delayed rupture proportion of giant paraclinoid aneurysms.

The 'bendy' basilar: progressive aneurysm tilting and arterial deformation can be a delayed outcome after coiling of large basilar apex aneurysms

BACKGROUND

Morphological changes in the basilar artery and the artery-aneurysm relationship following coiling of large basilar apex aneurysms may induce morbidity.

METHODS

The basilar artery radius-of-curvature was measured along its center line on volumetrically reconstructed images formatted along the plane of curvature. The aneurysm-tilt-angle was measured between the distal basilar and the vertical long axis of the aneurysm. The measurements were compared between small (<10 mm) and large (≥10 mm) aneurysms on baseline and follow-up studies. The volume (mm³) and mass (g) of the deployed coils was also compared.

RESULTS

Among 94 consecutive aneurysms, 62 (66%) were <10 mm and 32 (34%) were ≥10 mm. The mean aneurysm size and volume was 9 mm (±4) and 507 mm³(±1366) respectively. The median aneurysm follow-up was 24 months (IQR 6-59). There was no difference between the groups based on age, gender, or associated comorbidities. The coil mass was 0.4 g (±0.2) for aneurysms <10 mm and 1.9 g (±1.6) for aneurysms ≥10 mm (P<0.0001). The total coil volume was 32 (±20) mm³ for aneurysms <10 mm and 187 (±172) mm³ for aneurysms ≥10 mm (P<0.0001). Aneurysms ≥10 mm tilted 13.5^o (±14.4) compared with 1.1^o (±2.8) for aneurysms <10 mm (P<0.0001). The basilar artery became more curved by 1.3 (±9.4) mm for aneurysms ≥10 mm and 0.25 (±2.1) mm for aneurysms <10 mm (P=0.0002). Other than size of the coiled aneurysms no other factors correlated with the geometrical changes.

CONCLUSION

Large coiled basilar apex aneurysms may be more prone to aneurysm tilting and bending of the basilar artery. Speculative causes include the weight of the coil mass and the biomechanical forces exerted on the coiled aneurysm.

Giant Basilar Artery Aneurysm Involving the Origin of Bilateral Posterior Cerebral and Superior Cerebellar Arteries: Neck Reconstruction with pCONus-Assisted Coiling

Giant aneurysms of the basilar artery are rare and are frequently associated with obstructive hydrocephalus and brainstem compression. Treatment still remains a challenge both for neurosurgeons and for interventional neuroradiologists. Cases reported in the literature are anecdotal and, overall, their outcomes are poor. We present the case of a patient with a giant aneurysm of the basilar artery tip, involving the origin of both the posterior cerebral and superior cerebellar arteries, who underwent coiling and ventriculoperitoneal shunting for associated obstructive hydrocephalus. A pCONus ® stent (Phenox; Bochum, Germany) was detached with its petals opened over the ostia of the parent vessels, with the aim being to reconstruct the neck of the aneurysm and to preserve the flow in the parent vessel. Moreover, the presence of the stent was useful to maintain the coils within the dome of the aneurysm. The pCONus is a new neurovascular device that is also useful for treating cases of complex basilar artery aneurysms when the ostia of the parent vessel origin is at the level of the aneurysm neck.

Extensive bone erosion caused by pseudotumoral aneurysm growth

Carotid ophthalmic aneurysms constitute 0.9-6.5% of the aneurysms of the ICA with up to 20% of the cases presenting with visual symptoms. We report a case of an adult woman, presented with chronic headaches and protracted visual alterations progressing to left eye amaurosis. Neuroradiological exams, revealed a giant partially thrombosed carotid ophthalmic aneurysm extending anteriorly, causing pseudotumoral spheno-orbital bone erosion. The patient underwent surgical clipping, evacuation of the thrombotic mass and decompression of the optic pathways with rapid recovery of the vision. This unusual case, contributes to the available body of evidence on aneurysms growth.

Hydrocephalus caused by unilateral foramen of Monro obstruction: A review on terminology

Background:

Hydrocephalus caused by unilateral foramen of Monro (FM) obstruction has been referred to in literature by many different terminologies. Precise terminology describing hydrocephalus confined to just one lateral ventricle has a very important prognostic value and determines whether or not the patient can be shunt free after an endoscopic procedure.

Methods:

Aiming to define the best term for unilateral FM obstruction, 19 terms were employed on PubMed database (http://www.ncbi.nlm.nih.gov/pubmed) as quoted phrases.

Results:

A total of 194 articles were found. Four patterns of hydrocephalus were discriminated as a result of our research term query and were divided by types for didactic purpose. Type A - partial dilation of the lateral ventricle; Type B - pure unilateral obstruction of the FM; Type C - previously shunted patients with secondary obstruction of the FM; and Type D - asymmetric lateral ventricles with patent FM.

Conclusion:

In unilateral FM obstruction hydrocephalus, an in-depth review on terminology application is critical to avoid mistakes that may compromise comparisons among different series. This terminology review suggests that Type B hydrocephalus, i.e., the hydrocephalus confined to just one lateral ventricle with no other sites of cerebrospinal fluid circulation blockage, are best described by the terms unilateral hydrocephalus (UH) and monoventricular hydrocephalus, the first being by far the most popular. Type A hydrocephalus is best represented in the literature by the terms uniloculated hydrocephalus and loculated ventricle; Type C hydrocephalus by the terms isolated lateral ventricle and isolated UH; and Type D hydrocephalus by the term asymmetric hydrocephalus.

Research progress on vertebrobasilar dolichoectasia

Vertebrobasilar dolichoectasia (VBD) is a rare disease characterized by significant expansion, elongation, and tortuosity of the vertebrobasilar arteries. Current data regarding VBD are very limited. Here we systematically review VBD incidence, etiology, characteristics, clinical manifestations, treatment strategies, and prognosis. The exact incidence rate of VBD remains unclear, but is estimated to be 1.3% of the population. The occurrence of VBD is thought to be due to the cooperation of multiple factors, including congenital factors, infections and immune status, and degenerative diseases. The VBD clinical manifestations are complex with ischemic stroke as the most common, followed by progressive compression of cranial nerves and the brain stem, cerebral hemorrhage, and hydrocephalus. Treatment of VBD remains difficult. Currently, there are no precise and effective treatments, and available treatments mainly target the complications of VBD. With the development of stent technology, however, it may become an effective treatment for VBD.

[Anterior cerebral artery aneurism presenting as a third ventricular mass and hydrocephalus. Case report]

Aneurysms which appear as third ventricular masses are uncommon; most are giant aneurysms arising from the basilar apex. We present the case of a 67-year-old male who was admitted to hospital with a 4-week history of gait instability, urinary incontinence and progressive visual loss. A cranial computed tomography scan revealed a hyperdense mass in the third ventricle with triventricular dilatation. Cerebral magnetic resonance imaging, magnetic resonance-angiography and conventional angiography identified this lesion as a partially thrombosed aneurysm of the anterior cerebral artery. To our knowledge, this is the first report of an anterior cerebral artery aneurysm with these clinical and radiological features.

Endoscopic third ventriculostomy in the presence of large or giant basilar artery aneurysms

BACKGROUND

Endoscopic third ventriculostomy (ETV) is an effective treatment of obstructive hydrocephalus (OH). However, the presence of a large or giant basilar aneurysm is generally considered a contra-indication to ETV for treating hydrocephalus. We report the feasibility and efficacy of ETV for the treatment of hydrocephalus in the presence of such aneurysms.

METHODS

We performed a retrospective chart analysis of patients that underwent ETV for large or giant basilar aneurysm-associated hydrocephalus between January 2003 and January 2011.

RESULTS

During this period, 78 patients were treated by ETV. Of these, three patients presented with symptomatic hydrocephalus associated with a large giant basilar aneurysm (n = 3). Two of those patients had a history of previous subarachnoid hemorrhage (SAH) with intraventricular hemorrhage (IVH) 11 years and 13 years before ETV. Both aneurysms were embolized preoperatively. The third patient presented with OH due to an unruptured basilar artery aneurysm. There was no operative complication and symptoms resolution was observed in all patients at last follow-up.

CONCLUSIONS

ETV is a safe and effective alternative to ventriculo-peritoneal shunting in patients with hydrocephalus caused by large or giant basilar artery aneurysms. In addition, a history of SAH/IVH should not be considered a contra-indication to ETV.

Giant fusiform basilar artery aneurysm causing obstructive hydrocephalus

A 58-year-old man presented with a sudden onset gait disturbance and urinary incontinence. Magnetic resonance (MR) imaging and MR angiography showed a fusiform basilar artery aneurysm, 2 cm in diameter and 5 cm long. The aneurysm was thrombosed except the ectatic basilar artery flowing through it. Compression of the cerebrospinal fluid (CSF) pathways caused obstructive hydrocephalus with resultant transependymal CSF leakage. Conventional angiography missed the aneurysm. A one-sided ventriculoperitoneal shunt was placed to treat the patient's hydrocephalus. The patient's symptoms improved after surgery. MR imaging and MR angiography were useful noninvasive methods of detecting the aneurysm, defining its relationship with surrounding structures, and determining the cause of the hydrocephalus.

Aneurysm of the distal anterior cerebral artery radiologically mimicking a ventricular mass

The ventricular system is a rare localization for intracranial aneurysms. Most ventricular aneurysms arise from a distal branch of the choroidal arteries and a major branch point of the circle of Willis. A 41-year-old-man suffering from dizziness of 2 weeks' duration was admitted to the clinic. On radiological examination, he had a well-circumscribed mass involving the frontal horn of the right lateral ventricle without radiological evidence of a prior or recent hemorrhage. Localization and radiological appearance were not typical of a ventricular mass and did not allow diagnosis. After cerebral angiography, an aneurysm arising from the distal anterior cerebral artery was incidentally found in an intraventricular location. This unruptured aneurysm was successfully treated via the endovascular route. The authors describe the unusual case of a distal anterior cerebral artery aneurysm with a dome extending into the right lateral ventricle, which appears to be the first such case in the literature. Angiography may be helpful to neurosurgeons in avoiding the disastrous complications of a biopsy procedure in such unusual cases.

Endoscopic third ventriculostomy in obstructive hydrocephalus due to giant basilar artery aneurysm

Obstructive hydrocephalus due to giant basilar artery (BA) aneurysm is a rare finding, and endoscopic treatment has not been reported. Here the authors present their experience with endoscopic third ventriculostomy (ETV) in obstructive hydrocephalus due to giant BA aneurysm. Between December 2000 and March 2007, 3 patients (2 men and 1 woman; age range 32–80 years) underwent an ETV for the treatment of obstructive hydrocephalus caused by a giant BA aneurysm. All 3 patients presented with cephalgia, nausea, vomiting, and a variable decrease in consciousness. An obstructive hydrocephalus caused by a giant BA aneurysm was found in each case as the underlying pathological entity. Intraoperatively, a narrowing of the third ventricle by upward displacement of the tegmentum was found in all 3 patients. A standard ETV was performed and included an inspection of the prepontine cisterns. The endoscopic treatment was successful in all patients with respect to clinical signs and radiological ventricular enlargement. No complications were observed. In all, the endoscopic ventriculostomy was proven to be a successful treatment option in obstructive hydrocephalus even if it is caused by untreated giant BA aneurysm.

Hemodynamics of Cerebral Aneurysms

The initiation and progression of cerebral aneurysms are degenerative processes of the arterial wall driven by a complex interaction of biological and hemodynamic factors. Endothelial cells on the artery wall respond physiologically to blood-flow patterns. In normal conditions, these responses are associated with nonpathological tissue remodeling and adaptation. The combination of abnormal blood patterns and genetics predisposition could lead to the pathological formation of aneurysms. Here, we review recent progress on the basic mechanisms of aneurysm formation and evolution, with a focus on the role of hemodynamic patterns.

Basilar apex aneurysm manifesting as third ventricular mass and obstructive hydrocephalus--case report--

A 58-year-old male, with a past history of hypertensive thalamic hemorrhage 12 years before, presented with gradually exaggerating gait disturbance, memory disturbance, and urinary incontinence. On admission, he had gait disturbance represented by petit pas and anteropulsion in addition to significant recent memory disturbance. Cranial computed tomography (CT) revealed a hyperdense mass in the third ventricle with triventricular dilation. Cerebral magnetic resonance (MR) imaging and MR angiography identified the third ventricular lesion as saccular basilar apex aneurysm. No other intracranial abnormal intensity contributing to his clinical symptoms was recognized. Cervical MR angiography showed normal findings. Cerebral blood flow (CBF) measurements revealed diffuse CBF reduction in the cerebral hemisphere. The patient underwent coil embolization which accomplished complete aneurysm occlusion. He showed only slight improvement in his gait disturbance after embolization, and CT following embolization revealed persistent ventriculomegaly. Ventriculoperitoneal shunting was carried out. Intraoperative neuroendoscopy demonstrated cerebrospinal fluid (CSF) obstruction caused by the embolized aneurysm at the level of the third ventricle, with normal CSF findings. Postoperatively his gait disturbance and intellectual impairment showed remarkable improvement. Basilar apex aneurysm associated with obstructive hydrocephalus has complex underlying pathology and should be treated by a combination of definitive aneurysm obliteration and CSF diversion.

Successful treatment of a thrombosed posterior cerebral artery aneurysm causing obstructive hydrocephalus

The authors report a 49-year-old man who presented with obstructive hydrocephalus caused by a thrombosed posterior cerebral artery aneurysm. He underwent an endoscopic third ventriculostomy for the obstructive hydrocephalus followed by endovascular occlusion for the aneurysm. To our knowledge, this is the first report of a thrombosed posterior cerebral artery aneurysm presenting with obstructive hydrocephalus treated by the combination of endoscopic and endovascular techniques.