Giant basilar artery aneurysm with intramural hemorrhage and then disastrous hemorrhage: case report

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.

Trauma may affect vasa vasorum to promote thrombosis and enlargement of intracranial aneurysms: A case report

Background

Thrombosed intracranial aneurysm (IA) is likely to occur in large or giant IAs. Almost all thrombosed IAs are found already in a thrombosed state, and few reports have depicted the process of thrombosis in unthrombosed aneurysm. Moreover, no reports appear to have described IA in which thrombosis accelerated after trauma.

Case Description

We report herein a case in which an unthrombosed large cerebral aneurysm rapidly thrombosed and grew within 3 months after trauma. The highlight in this unusual case was that during surgery, the aneurysm and anterior skull base were adherent and some blood vessels bridged between the aneurysm and dura mater. Histologically, intramural hemorrhage was seen in the tunica media of the aneurysm.

Conclusion

Trauma may act as a "second hit" causing adhesion between IAs and surrounding tissues, accelerating inflammation of the vasa vasorum and aneurysmal walls, and thrombosis in IAs.

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.

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.

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.

The many faces of intracranial arterial dissections

Intracranial arterial dissecting diseases are rare and challenging diseases with a high associated morbidity and mortality. Their common pathomechanic origin is related to blood entering the vessel wall via an endothelial and intimal tear. Depending on the fate of the thus established intramural hematoma, different symptoms may ensue including mass effect, subarachnoid hemorrhage or ischemia. If the mural hematoma ruptures all vascular layers of the intradural artery, a subarachnoid hemorrhagic will occur. If the intramural hematoma reopens distally into the parent vessel on the other hand, ischemic embolic events may happen following intramural clot formation. If the mural hematoma does neither open itself into the parent vessel nor into the subarachnoid space, the vessel wall may dilate leading to occlusion of perforator branches and local ischemia. Organization of the mural hematoma may result in a chronic dissecting process which may eventually lead to formation of a "giant partially thrombosed" aneurysm with thrombus of varying ages within the vessel wall, ingrowth of vasa vasorum and recurrent dissections with subsequent growth of the aneurysm from the periphery. Treatment strategies of these diseases should take the underlying pathomechanism into consideration and include, depending on the presentation medical treatment, parent vessel occlusion, flow reversal or diversion, surgical options or a combined treatment protocol.

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.

Growth and rupture mechanism of partially thrombosed aneurysms

SUMMARY

Within the group of giant and large aneurysms the subgroup of the so-called "partially thrombosed" aneurysms can be differentiated according to clinical and neuroimaging findings. The present study was carried out to determine the site of bleeding of these aneurysms and what implications concerning their pathomechanism can be drawn from these findings. Twenty patients aged two to 77 (mean 44) years who exhibited a partially thrombosed aneurysm that had recently bled were included. Images (MRI including T1 pre- and postcontrast and T2 weighted images in multiple planes, CT and digital subtraction angiography) and patients' charts were reviewed. MRI showed an onion-skin appearance of the thrombus in 19 patients, rim enhancement of the aneurysm wall (either partial or complete) in 17, and a perifocal edema in 16 patients. The acute hemorrhage was typically crescent-shaped and located at the periphery of the aneurysm, distant from the perfused lumen of the aneurysm within the thrombosed part of the aneurysm. The current denomination "partially thrombosed" intracranial arterial aneurysms leads to the presumption that thrombus is present endoluminal whereas in fact the site of hemorrhage is within the vessel wall. A more accurate nomination would, therefore, be "aneurysms with intramural hemorrhage". The enhancing wall and the edematous reaction of the adjacent brain parenchyma might be a sign for an inflammatory pathomechanism which is reinforced by histological and pathophysiological studies. This disease should be regarded as a clinical entity separate from saccular or non-thrombosed giant or large aneurysms.

Enlarging vertebrobasilar nonsaccular intracranial aneurysms: frequency, predictors, and clinical outcome of growth

Object. Vertebrobasilar nonsaccular intracranial aneurysms (NIAs) are characterized by elongation, dilation, and tortuosity of the vertebrobasilar arteries. The goal of this study was to define the frequency, predictors, and clinical outcome of the enlargement of vertebrobasilar NIAs.

Methods. Patients with vertebrobasilar fusiform or dolichoectatic aneurysms demonstrated on imaging studies between 1989 and 2001 were identified. In particular, patients who had undergone serial imaging were included in this study and their medical records were retrospectively reviewed. Prospective information was collected from medical records or death certificates when available. Both initial and serial imaging studies were reviewed. The authors defined NIA enlargement as a change in lesion diameter greater than 2 mm or noted on the neuroradiologist's report. A Cox proportional hazards regression was used to model time from diagnosis of the vertebrobasilar NIA to the first documented enlargement as a function of various predictors. The Kaplan-Meier method was used to study patient death as a function of aneurysm growth.

Of the 159 patients with a diagnosis of vertebrobasilar NIA, 52 had undergone serial imaging studies including 25 patients with aneurysm enlargement. Lesion growth significantly correlated with symptomatic compression at the initial diagnosis (p = 0.0028), lesion type (p < 0.001), and the initial maximal lesion diameter (median 15 mm in patients whose aneurysm enlarged compared with median 8 mm in patients whose aneurysm did not enlarge; p < 0.001). The mortality rate was 5.7 times higher in patients with aneurysm growth than in those with no enlargement after adjustment for patient age (p = 0.002).

Conclusions. Forty-eight percent of vertebrobasilar NIAs demonstrated on serial imaging enlarged, and this growth was associated with significant morbidity and death. Significant risk factors for aneurysm enlargement included symptomatic compression at the initial diagnosis, transitional or fusiform vertebrobasilar NIAs, and initial lesion diameter. Further studies are necessary to determine appropriate treatments of this disease entity once enlargement has been predicted or occurs.

[Giant aneurysm of fast development]

The percentage of aneurysms measuring more than 2'5 cm in diameter ranges from 3 to 13%, and occur more commonly in females. They come to clinical attention later than nongiant aneurysms, but 20% of them appear in patients 20 years of age or younger. Its natural history is incompletely understood. We present the case of a 24-year-old female admitted following a generalized seizure with postictal dysphasia and right hemiparesis caused by a subarachnoid hemorrhage due to a ruptured giant aneurysm located in the left temporal fossa, who died few hours later because of rebleeding. This patient had been followed during the last seven years at our unit because of untreated frontal osteomas, without evidence of any intracranial lesion in the computerized axial tomography (CT). Some months before her death, she had suffered a left micotic otitis, and she was studied because of the reappearance of her left cephalalgia without neurological deficit. This case is another evidence of quick appearance of a giant aneurysm, "silent" until the fatal outcome.

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

We report a rare case of a non-ruptured basilar bifurcation aneurysm presenting as a third ventricular mass producing unilateral obstructive hydrocephalus. This is the first reported case of its kind. A 70 year old woman presented with a giant basilar bifurcation aneurysm in which the aneurysm protruded into the third ventricle as a mass causing unilateral left hydrocephalus. The patient gradually became disoriented and developed a right hemiparesis and global aphasia. The right vertebral artery was occluded by placing coils intravascularly followed by an endoscopic septostomy. The patient's neurological state dramatically improved immediately. One month after the septostomy, however, the aneurysm ruptured and the patient eventually died. Treatment of the hydrocephalus only was selected instead of direct surgery or an intravascular procedure on the aneurysm, which eventually ruptured. The mechanisms for the unilateral hydrocephalus and the rupture of the aneurysm are described. The treatment strategy for these lesions is also discussed.