Recanalization of completely thrombosed giant aneurysm: case report

Spontaneous thrombosis of a large unruptured intracranial aneurysm causing ischemic stroke due to occlusion of the parent artery: A case report and literature review

Spontaneous thrombosis of an unruptured large or giant saccular intracranial aneurysm is a well-known phenomenon and can cause ischemic stroke (IS), which is a rare event. The possible pathogenic mechanisms of IS include distal embolic occlusion secondary to migration of the intra-aneurysmal thrombus, occlusion of the parent artery lumen caused by the retrograde extension of the aneurysmal thrombosis, external compression of the parent artery due to the increased aneurysmal mass effect. Among these, IS due to simultaneous thromboses of the aneurysm and its parent artery is extremely rare, with only a few cases reported in the literature. Herein, we present a case of a 18-year-old woman who suffered an acute IS, attribute to spontaneous complete thrombosis of an unruptured large saccular aneurysm of the right middle cerebral artery with occlusion of the parent artery, and we review the literature simultaneously.

A complete thrombotic large aneurysm at the nonbranching segment of the distal anterior cerebral artery mimicking a cavernous malformation: illustrative case

BACKGROUND

Thrombotic aneurysms at the nonbranching segment of the distal anterior cerebral artery (ACA) are extremely rare and difficult to differentiate from cavernous malformations by radiographic features alone.

OBSERVATIONS

Computed tomography and magnetic resonance imaging of a 30-year-old female patient with a chronic headache complaint revealed a 22-mm frontal lobe mass. The mass showed heterogeneous mixed intensity and hemosiderin deposits on magnetic resonance images. It was not visualized by conventional angiography, indicating that the mass and ACA/other vessels were not connected. The patient was preoperatively diagnosed with a cavernous malformation. However, during resection, the mass surface was white and smooth, different from a cavernous malformation. Although the mass was adherent to the pericallosal artery branch, no luminal continuity was observed. After detachment, the mass was completely resected. Pathological and immunohistochemical findings indicated a vessel wall and interior thrombus. The patient was rediagnosed with a thrombotic aneurysm at the distal ACA nonbranching segment and discharged 10 days postsurgery without neurological deficits.

LESSONS

Because radiographic findings of thrombotic aneurysm and cavernous malformation are similar, mass lesions in contact with major arteries should be differentiated as thrombotic aneurysms, even when the artery lumen appears disconnected from the mass.

A pediatric case of completely thrombosed giant cavernous carotid aneurysm with ipsilateral ICA occlusion mimicking an intra-axial cystic lesion: a case report and review of the literature

INTRODUCTION

There have been a few cases where completely thrombosed cavernous carotid artery (CCA) aneurysms have resembled neoplasms based on neuroimaging data, but no reports have been documented in children.

CASE REPORT

We describe an unusual pediatric case of a huge cavernous sinus mass mimicking a cystic neoplasm with peripheral rim enhancement on magnetic resonance imaging (MRI), where the surgery and subsequent histopathological investigation revealed that this mass was a completely thrombosed giant aneurysm of the CCA. The patient showed postoperatively no new neurological deficits and discharged a week later after surgery.

CONCLUSIONS

In this case report, we describe a pediatric case of a completely thrombosed giant CCA aneurysm with ipsilateral internal carotid artery (ICA) occlusion, which imitates an intra-axial cystic lesion on MRI.

Spontaneous Disappearance of Unruptured Intracranial Aneurysm: A Case Report

Spontaneous resolution or thrombosis of giant or ruptured intracranial aneurysms is occasionally reported. However, spontaneous resolution of unruptured aneurysms without any intervention is extremely rare. Recently, we encountered a case of spontaneous resolution of a small unruptured aneurysm of the anterior communicating artery. We describe this rare case and discuss the mechanism of resolution with a review of the related literature.

Trapping, dome puncture, and direct suction decompression in conjunction with assistant superficial temporal artery- middle cerebral artery bypass to clip giant internal carotid artery bifurcation aneurysm

Background:

Very large and giant aneurysms (≥20 mm) of the internal carotid artery (ICA) bifurcation (ICAbif) are definitely rare, and optimal treatment is not established. Endovascular treatments are reported as suboptimal due to difficulties of complete occlusion and tendencies to recanalization. Therefore, direct surgery remains an effective strategy if the clipping can be performed safely and reliably, although very difficult.

Case Description:

Two cases of ICAbif aneurysms (>20 mm) were treated. Prior assistant superficial temporal artery (STA)-middle cerebral artery (MCA) bypass was performed to avoid ischemic complications during prolonged temporary occlusion of the arteries in both cases. In Case 1 (22-mm aneurysm), the dome was inadvertently torn in applying the clip because trapping had resulted in insufficient decompression. Therefore, in Case 2 (28-mm aneurysm), almost complete trapping of the aneurysm and subsequent dome puncture was performed, and the aneurysm was totally deflated by suction from the incision. This complete aneurysm decompression allowed safe dissection and successful clipping.

Conclusion:

Trapping, deliberate aneurysm dome puncture, and suction decompression from the incision in conjunction with assistant STA-MCA bypass can achieve complete aneurysm deflation, and these techniques enable safe dissection of the aneurysm and direct clipping of the aneurysm neck. Direct clipping with this technique for very large and giant ICAbif aneurysms may be the optimal treatment choice with the acceptable outcome if endovascular treatment remains suboptimal.

Serpentine aneurysm of the posterior cerebral artery treated by internal maxillary artery bypass followed by parent artery occlusion: a case report and literature review

Serpentine aneurysms of the posterior cerebral artery (PCA) treated by the internal maxillary artery (IMA) bypass are rare. Here, the authors report the case of a 34-year-old male patient who presented with a half-year history of gradual severe headache and right-sided limb monoparesis and paresthesia lasting for 1 week. Preoperative angiograms showed a serpentine aneurysm in the left distal PCA, which was treated with internal maxillary artery-radial artery-posterior cerebral artery (IMA-RA-PCA) bypass followed by parent artery occlusion (PAO). The postoperative course was uneventful; radiological images revealed that the aneurysm disappeared, and there was good graft patency and excellent perfusion of the distal PCA territories. To the authors' knowledge, this is the first and only case of distal PCA serpentine aneurysm to be treated by IMA-RA-PCA bypass followed by proximal PAO. These findings suggest that IMA bypass surgery is a good and feasible treatment option for serpentine aneurysms of the PCA that can preserve the parent artery. Moreover, the anatomic segments of the PCA and different treatment options available for PCA serpentine aneurysms are also discussed in this study.

Thrombotic Aneurysm of Posterior Inferior Cerebellar Artery

BACKGROUND

Spontaneous thrombosis of an intracranial aneurysm is rare but is common in fusiform or large cystic aneurysms, which result in subarachnoid hemorrhage after rupture. This case reports a 47-year-old woman with subarachnoid hemorrhage who developed spontaneous thrombosis of an aneurysm due to rupture of the posterior inferior cerebellar aneurysm.

CASE DESCRIPTION

The patient was admitted to the hospital with history of sudden headache and vomiting for 3 days. According to early imaging findings, she was initially diagnosed as having a cavernous hemangioma with hemorrhage in the left cerebellum, but according to the intraoperative pictures and postoperative pathologic results, the diagnosis was an aneurysm with thrombosis.

CONCLUSIONS

This case represents a rare but important complication of ruptured intracranial aneurysm, which can be easily misdiagnosed or ignored. It should be given great attention and considered in patients with subarachnoid hemorrhage who are negative for imaging examinations.

Intracranial Serpentine Aneurysms: Spontaneous Changes of Angiographic Filling Pattern

BACKGROUND AND PURPOSE

Serpentine aneurysms are partially thrombosed aneurysms with an eccentrically located tortuous intra-aneurysmal vascular channel. The large size, distinctive neck anatomy, and supply of the brain parenchyma by the outflow tract pose technical challenges in treatment. The aim of this study was to discuss the endovascular treatment results and illustrate the dynamic nature of serpentine aneurysms. Spontaneous transformation of saccular and fusiform aneurysms into serpentine morphology, along with a case of serpentine-into-fusiform aneurysm transformation during follow-up, is presented.

MATERIALS AND METHODS

A retrospective analysis from 3 institutions revealed 15 patients with serpentine aneurysms who underwent diagnostic evaluation and endovascular treatment. Nine of the 15 patients underwent endovascular occlusion of the parent vessel with detachable balloon or coils. Six of the 15 patients underwent aneurysm and parent artery occlusion with coiling.

RESULTS

In 11 patients, improvement or resolution of symptoms was achieved by an endovascular approach without any treatment-related morbidity. Morbidity related to treatment in the immediate postoperative period was seen in 3 patients, with resolution of the deficits at long-term follow-up in 2 patients and persistence of a mild deficit in 1 patient. Endovascular treatment failed to achieve resolution of symptoms in a case with a basilar tip aneurysm treated by aneurysm coiling.

CONCLUSIONS

Serpentine aneurysms are dynamic structures with spontaneous transformation possible from a saccular or fusiform shape into a serpentine configuration. An endovascular approach by parent vessel occlusion or intra-aneurysmal occlusion is a successful treatment technique for serpentine aneurysms.

Completely Thrombosed Giant Intracranial Aneurysm with Spontaneous Thrombosis of the Parent Artery: Is It Nature's Divine Intervention and a Self-Cure?

BACKGROUND

Although partial thrombosis is common with intracranial aneurysms, complete aneurysmal thrombosis is extremely rare. An even rarer and seldom reported phenomenon is the spontaneous complete occlusion of the parent artery in the presence of a thrombosed aneurysm. Given the unclear natural history of this phenomenon, therapeutic decision making may be rather difficult. Here we report a case of right cavernous carotid artery aneurysm with spontaneous right internal carotid artery (ICA) thrombosis in a 45-year-old man.

CASE DESCRIPTION

Our patient presented almost 1 month after an episode of sudden-onset severe holocranial headache associated with vomiting that had resolved completely within 2 days. He was neurologically intact at the time of presentation. A computed tomography (CT) scan done at the time of ictus showed a rounded hyperdensity with the epicenter at the right parasellar region along with nonvisualization of the ipsilateral ICA on CT angiography. Magnetic resonance imaging (MRI) suggested a diagnosis of a completely thrombosed right cavernous segment ICA aneurysm. Intra-arterial angiography confirmed a complete ipsilateral ICA thrombosis and a good arterial cross-flow from the left side to the bilateral anterior and middle cerebral artery territories. We started the patient on oral aspirin and a close clinicoradiologic follow-up after having decided against any active intervention.

CONCLUSIONS

Spontaneous thrombosis of an intracranial aneurysm and the parent artery is rare, with only a few cases reported in the literature. In the absence of symptoms and adequate collateral circulation, these patients are perhaps best managed conservatively.

Giant Serpentine Aneurysm of the Middle Cerebral Artery

BACKGROUND

Giant serpentine aneurysms (GSAs) are a subgroup of giant intracranial aneurysms, distinct from saccular and fusiform varieties, that are defined as partially thrombosed giant aneurysms with tortuous internal vascular channel. Clinicopathologic characteristics of middle cerebral artery GSAs have been rarely reported in the literature, with discussion of radiologic characteristics only. We clarify patient clinical and neuroradiologic features and discuss the mechanism of formation and progression.

CASE DESCRIPTION

A 43-year-old woman presented with a GSA arising from the middle cerebral artery. There was a separate inflow and outflow channel of the aneurysm, with the outflow channel feeding the distal branches of the parent artery and supplying normal brain parenchyma. The GSA was treated successfully by aneurysmectomy and superficial temporal artery-middle cerebral artery bypass followed by proximal occlusion and vascular reconstruction. An aneurysm specimen was examined to correlate pathologic findings and morphologic characteristics.

RESULT

Pathologic results showed that thickness of the aneurysmal wall was typically increased and varied, and no internal elastic lamina or endothelial lining could be identified. The sac contained thrombi of various ages with recanalizing vessel formation and chronic inflammation infiltration. Intimal hyperplasia and neoangiogenesis in the wall and hyaline degeneration of the media were observed. Vessels coursing in their adventitia showed mucoid changes, which are responsible for the contrast enhancement of the aneurysmal rim on computed tomography scan.

CONCLUSIONS

GSAs are a specific pathologic entity with unique morphologic and pathologic characteristics that can affect intracranial blood vessels. The pathogenic mechanisms are unclear; this report suggests that GSAs may be associated with degeneration of the vascular wall.

Serpentine Cavernous Aneurysm Presented with Visual Symptoms Improved by Endovascular Coil Trapping

This report describes a case of a serpentine fusiform aneurysm of the internal carotid artery in a patient who presented with visual disturbances. The serpentine aneurysm was treated successfully by coil trapping and occlusion of the parent artery, accompanied by balloon dilation. Nine months post-operatively, the patient's visual acuity had improved considerably.

A Contralateral Transcondylar Fossa Approach with Bilateral V3 Segment Exposure for Repairing Complex Vertebral Artery Aneurysms

BACKGROUND AND IMPORTANCE

Microsurgical treatment for vertebral artery aneurysms can be approached through the lateral aspect of the brainstem and cerebellum. A contralateral approach may be selected in complex aneurysms with tortuous running and the intracranial vertebral artery distal to the aneurysm located in the contralateral cerebellopontine angle. When repairing the aneurysm, exposing the V3 segment before craniotomy is advantageous. We describe the detailed surgical procedures of the contralateral transcondylar fossa approach with bilateral V3 segment exposure for the repair of a complex vertebral artery aneurysm.

CLINICAL PRESENTATION

A 48-year-old woman presented with a 23-mm unruptured thrombosed fusiform aneurysm in the right vertebral artery. The aneurysm and the V4 segment distal to it deviated to the left, and the aneurysm was compressing the left anterior aspect of the medulla oblongata. We treated the patient with trapping and thrombectomy, using a contralateral transcondylar fossa approach with bilateral V3 exposure. During the procedure, proximal vascular control was achieved by occluding the contralateral V3 segment and distal control was achieved by occluding the V4 segment. The aneurysm was successfully trapped and decompressed. The patient's postoperative course was good and she was discharged with a modified Rankin Scale score of 0.

CONCLUSIONS

The contralateral transcondylar fossa approach with bilateral V3 exposure is feasible for the repair of complex vertebral artery aneurysms showing a deviated and difficult to access V4 segment proximal to the aneurysm. Bilateral V3 exposure may also facilitate aneurysm bypass procedures such as those using a V3-V4 anastomosis.

Radical treatment for bilateral vertebral artery dissecting aneurysms by reconstruction of the vertebral artery

OBJECTIVE

Bilateral vertebral artery dissecting aneurysms (VADAs) have a poor prognosis because progressive enlargement of the aneurysms compresses the brainstem or causes subarachnoid hemorrhage. The trapping of 1 vertebral artery (VA) places increased hemodynamic stress on the contralateral VA and may lead to enlargement and rupture. Therefore, management strategies are controversial. This study describes a radical treatment for bilateral VADAs using bypass surgery.

METHODS

Seven patients with bilateral VADAs were included. Three patients were treated by trapping of 1 VA via coiling or clipping at another hospital; the previously treated VA in 1 patient and the contralateral untreated VA in 2 patients subsequently enlarged. The other 4 patients presented without previous intervention and progressive enlargement of the aneurysms.

RESULTS

The post–coil embolization patients underwent V3–posterior cerebral artery (PCA) bypass and trapping. The other 4 patients underwent VA reconstruction via V3–V4 or V4–V4 bypass, with contralateral trapping on a separate day in 3 patients and observation in 1 patient. Perioperative complications included 1 case of cerebrospinal fluid leakage for which the patient required an additional operation, 1 case of dysphagia and facial palsy due to sigmoid sinus thrombosis, and 1 case of dysphagia. The long-term outcomes of these patients were favorable.

CONCLUSIONS

Patients with bilateral VADAs require treatment on both sides. If VA trapping is performed first, the treatment options for the other side are limited to V3-PCA bypass and trapping. This procedure is effective; however, it is also invasive and technically difficult. In cases of bilateral VADAs in which it is feasible to reconstruct 1 side, the best approach is to begin by reconstructing the VA that appears technically easiest, followed by trapping of the contralateral VADA. This strategy allows enough time to suture vessels because contralateral reverse flow is maintained.

Spontaneous Thrombosis of an Unruptured Saccular Aneurysm Causing MCA Infarction

Spontaneous complete thrombosis of an unruptured intracranial aneurysm leading to ischemic stroke is rare. We present a case of a 56-year-old man who suffered an acute left middle cerebral artery (MCA) infarction, attributable to complete thrombosis of an unruptured saccular MCA bifurcation aneurysm with occlusion of the parent artery. The presenting hemiparesis and aphasia partially improved over a long hospital rehabilitation stay. Follow-up imaging demonstrated no recanalization of the aneurysm or parent vessels. To the best of our knowledge this is the first documented case of isolated MCA territory infarction due to complete spontaneous thrombosis of a saccular aneurysm.

Spontaneous thrombosis of giant intracranial aneurysm and posterior cerebral artery followed by also spontaneous recanalization

Background:

Spontaneous complete thrombosis of a giant aneurysm and its parent artery is a rare event. Their spontaneous recanalization is even rarer, with few reports.

Case Description:

A 17-year-old male patient presenting blurred vision and headache, with a history of seizures, was referred to our service. After further investigation with cranial computed tomography, magnetic resonance imaging (MRI), and cerebral angiography (CAG), it was diagnosed a thrombosed aneurysm of the posterior cerebral artery (PCA) and also complete thrombosis of the PCA. Three years later, he experienced visual worsening. A new MRI scan indicated flow both through the aneurysm and the left PCA, which was further confirmed by CAG. We decided for a noninterventional treatment combined with strict clinical follow-up. The patient continues to present with the previous neurological deficit, without recurrence of headaches.

Conclusions:

Thrombosis is not the final event in the natural history of giant aneurysms, and partial thrombosis does not preclude the risk of rupture. Thrombosed aneurysms may display additional growth brought about by wall dissections or intramural hemorrhages. Their treatment may be either surgical or involve endovascular procedures such as embolization. Thrombosed giant aneurysms are dynamic and unstable lesions. A noninterventional treatment is feasible, but aneurysmal growth or recanalization may suggest the need for a more active intervention.

Study and Therapeutic Progress on Intracranial Serpentine Aneurysms

An intracranial serpentine aneurysm (SA) is a clinically rare entity, and very few multi-case studies on SA have been published. The present study reviewed the relevant literature available on PubMed. The studied information included the formation mechanism and natural history of SA as well as its clinical manifestation, imaging characteristics, and current treatments. After reviewing the literature, we conclude that intracranial SA can be managed surgically and by endovascular embolization, but the degree of blood flow in normal brain tissue distal to the SA must be evaluated. A balloon occlusion test (BOT) or cross compression test is recommended for this evaluation. If the collateral circulation is sufficiently compensatory, direct excision or embolization can be performed. However, if the compensatory collateral circulation is poor, a bypass surgery is necessary. Satisfactory results can be achieved in the majority of SA patients after treatment. However, the size of the aneurysm may increase in some patients after endovascular treatment. Special attention should be paid to cases exhibiting a significant mass effect to avoid subsequent SA excision due to an intolerable mass effect. Satisfactory results can be achieved with careful treatment of SA.

Surgical Flow Alteration for the Treatment of Intracranial Aneurysms That Are Unclippable, Untrappable, and Uncoilable

OBJECTIVE

The treatment of complex intracranial aneurysms remains challenging. One approach is the application of surgical flow alteration to treat aneurysms that are neither clippable, trappable, or coilable. The efficacy and limitations of surgical flow alteration have not yet been established.

METHODS

Cases of complex aneurysms treated with surgical flow alteration (proximal occlusion with or without bypass, distal occlusion with or without bypass and bypass only) were included in this retrospective study.

RESULTS

Among a total of 16 cases, there were 7 giant aneurysms (≥25 mm diameter) and 9 large aneurysms (>10 mm diameter); 15 of 16 aneurysms were unruptured. There were 8 aneurysms located in the anterior circulation, while the other 8 were in the posterior circulation. Aneurysms were treated with proximal occlusion in 10 cases and distal occlusion in 5 cases; in 1 case, the aneurysm occluded spontaneously after bypass without parent artery occlusion. All but 2 cases underwent prior or concurrent bypass surgery. Complete obliteration of the aneurysm at the latest imaging follow-up was shown in 12 of 16 cases (75.0%). Bypass patency was confirmed in 13 of 15 cases (86.7%). Surgery-related morbidity developed in 3 cases (18.8%, Glasgow outcome scale of 4) and all were perforator infarctions. There were no mortalities.

CONCLUSION

Surgical flow alteration resulted in a high rate of aneurysmal obliteration with acceptable morbidity. Although several limitations remained, it could represent an alternative method for treating complex aneurysms.

Spontaneous Occluded Anterior Communicating Artery Aneurysm during Coil Embolization Treated with One Coil Insertion into Remaining Stump

Spontaneous thrombosis of a ruptured aneurysm during coil embolization is a rare event, and some reports on recanalization of a spontaneous occluded ruptured aneurysm have been published. We report on a case of a 54-year-old male who presented with a subarachnoid hemorrhage due to rupture of a small aneurysm of the anterior communicating artery (ACoA). Cerebral angiography confirmed the presence of the ACoA aneurysm, but, during coil embolization, the aneurysm was near completely occluded with a remaining small neck. A small coil was inserted into the remaining stump of the neck to prevent recanalization, and the angiographic result at 1 year after coil embolization showed complete obliteration of the aneurysm.

Thrombosis and spontaneous recanalization of a giant intracranial aneurysm: diagnostic and management pearls in a pediatric patient

The authors present the case of a boy who was successfully managed through the spontaneous thrombosis of a cavernous internal carotid artery (ICA) aneurysm, the subsequent occlusion of the ICA, its recanalization, and ultimate endovascular sacrifice, using only two angiograms because of the diagnostic capability of CT angiography. Spontaneous recanalization of the ICA following occlusion in the setting of a giant aneurysm has not been previously reported.

Spontaneous thrombosis in giant aneurysm of the anterior communicating artery complex in pediatric age: five-year follow-up

Intracranial aneurysms are rare in the pediatric population, especially in infancy, representing less than 1% of all aneurysms. In this age group, they are more frequent at the carotid bifurcation and in the posterior circulation, with a greater number of giant aneurysms and spontaneous aneurysm thrombosis when compared with the adults. They are life-threatening, and, therefore, early investigation, characterization of the lesion, and treatment are essential. The appropriate management depends on the child's condition, aneurysm characteristics, and the experience of a multidisciplinary team. Noninvasive and radiation-free imagiological studies play an important role in the diagnosis and follow-up of these young patients. We present the case of a 3-month-old boy with an intracranial hemorrhage secondary to the rupture of a giant aneurysm of the anterior communicating artery complex, with spontaneous thrombosis, which is a rare situation due to its location. A conservative approach was assumed and noninvasive evolutive imagiological studies revealed a reduction in the thrombosed aneurysm size and no signs of recanalization. The child recovered to his baseline neurological condition and has had no rehemorrhage until 5 years of follow-up.

Thrombosis and recanalization of small saccular cerebral aneurysm : two case reports and a suggestion for possible mechanism

Reports of thrombosis and recanalization of cerebral aneurysm are rare. We report two cases of small, saccular aneurysms in which spontaneous thrombosis had occurred during the preparation for endovascular coiling. Also, we review reported cases and propose the presumed pathogenesis.

Spontaneous regression of an unruptured and non-giant intracranial aneurysm

It is well known that spontaneous thrombosis in giant cerebral aneurysm is common. However, spontaneous obliteration of a non-giant and unruptured cerebral aneurysm has been reported to be rare and its pathogenic mechanism is not clear. We describe a case with rare vascular phenomenon and review the relevant literatures.

Spontaneous Thrombosis of Basilar Artery Aneurysm After Subarachnoidal Hemorrhage in a Patient With Thrombophilia and Recurrent Deep Venous Thrombosis

We report a patient with combined thrombophilia—protein C deficiency and mild hyperhomocysteinemia with total spontaneous thrombosis of a basilar tip aneurysm after subarachnoid hemorrhage, without neurological deficit. At admission, the patient had headache, drowsiness, and nausea, with no neurological deficit. Computed tomography (CT) did not show the presence of subarachnoid blood, and magnetic resonance examination revealed discrete remains of a subarachnoid hemorrhage in projections of temporal, frontal and occipital lobes, with no vascular abnormalities. Initial angiography showed a small basilar tip aneurysm and the patient was scheduled for endovascular treatment. A second angiography, performed before the planned endovascular treatment, did not show the aneurysm and complete thrombosis was suspected. A follow-up angiogram, 6 months after this event, showed preserved posterior cerebral circulation with no aneurysm present. The patient was discharged in good condition, without neurological deterioration. We did not find any previous reports of similar conditions.

Transformation of a cranial fusiform aneurysm into a pseudotumoral-like mass prior to spontaneous occlusion and regression

This report documents the evolution of a non-ruptured cranial fusiform aneurysm that underwent both spontaneous occlusion and regression. During this process, unique images of the aneurysm as a pseudotumoral-like mass were obtained. The pseudotumoral-like mass most likely reflected inflammation and secondary neovascularization within the aneurysm, supporting the theory that spontaneous aneurysmal healing involves an inflammatory process.

Partially thrombosed intracranial aneurysms: symptoms, evolution, and therapeutic management

BACKGROUND

Partially thrombosed intracranial aneurysms (PTIAs) are different from saccular or nonthrombosed giant or large aneurysms, as they are characterized by multiple intramural thrombotic phenomena related to recurrent vessel wall dissections.

METHODS

We retrospectively reviewed clinical and radiological files of 23 consecutive patients with PTIAs (mean age 49.3 years). Twenty-two lesions were studied by magnetic resonance imaging (MRI). Patients were managed by endovascular treatments, medically with steroids, or conservatively.

RESULTS

Thirteen patients presented with progressive neurological symptoms. Subarachnoid hemorrhage was suspected but not proven in three. At MRI, 90.9% of PTIAs caused mass effect; perilesional T2 hypersignal compatible with edema was evident in 13.6%. Aneurysmal wall enhancement was detectable in 63.2% of the PTIAs and considered a marker of inflammatory processes. Parent artery occlusion was performed in seven patients with clinical improvement in six. Selective coiling was proposed in three patients (one improved, one remained stable, and one experienced symptoms progression). Three patients were treated with steroids and improved. Ten patients were managed conservatively: eight because spontaneous thrombosis of the lesion had been diagnosed and two because of clinical and radiological stability.

CONCLUSIONS

The natural history of PTIAs is different from other aneurysms. They most commonly present with progressive neurological symptoms due to mass effect. MRI properly diagnoses PTIAs and allows precise follow-up, more accurately than angiography because it detects prominent "abluminal" features indicating inflammation and neovascularization. Spontaneous thrombosis is part of the natural history of PTIAs and it should be taken in consideration when discussing the therapeutic management.

Giant serpentine aneurysm of the middle cerebral artery

Giant serpentine aneurysms are rare and have distinct angiographic findings. The rarity, large size, complex anatomy and hemodynamic characteristics of giant serpentine aneurysms make treatment difficult. We report a case of a giant serpentine aneurysm of the right middle cerebral artery (MCA) that presented as headache. Treatment involved a superficial temporal artery (STA)-MCA bypass followed by aneurysm resection. The patient was discharged without neurological deficits, and early and late follow-up angiography disclosed successful removal of the aneurysm and a patent bypass graft. We conclude that STA-MCA bypass and aneurysm excision is a successful treatment method for a giant serpentine aneurysm.

Evolution of Giant P2-Posterior Cerebral Artery Aneurysm over 16 Years: Saccular to Serpentine

Giant intracranial aneurysms account for only about 5% of all intracranial aneurysms. Giant intradural aneurysms are associated with severe natural history, yet remain potentially curable. These aneurysms cause symptoms due to their mass effect, and only 14–35% of cases present with subarachnoid haemorrhage (SAH). The present case report is an imaging evolution of a giant posterior cerebral artery (PCA) aneurysm in a patient who was lost on follow-up from 1992 to 2008 giving insight into the natural history and morphologic evolution of giant serpentine aneurysms. Attempted surgery 16 years previously for a saccular PCA aneurysm produced encephalomalacia and created a more spacious perianeurysmal environment, preventing any mass effect on vital structures in its vicinity. This allowed the patient to have a long symptom-free period and also allowed the aneurysm to follow a morphologic evolution over a long period without causing symptoms which would have called for intervention. This unusual development gave a unique opportunity to study the evolution of a gaint serpentine aneurysm from a saccular aneurysm and also the clinical and morphologic changes in an aneurysm if it can be prevented from producing mass effect. The Coanda effect, or boundary wall effect, has been considered responsible for the development of the serpentine channel in the original globular aneurysm. However many Authors conclude that giant serpentine aneurysms are not derived from saccular aneurysms.

Giant serpentine aneurysms

Segal and McLaurin first described giant serpentine aneurysms, based on their distinct angiographic features, in 1977. These lesions are >or= 25 mm, partially thrombosed aneurysms with a patent, serpiginous vascular channel that courses through the aneurysm. There is a separate inflow and outflow of the aneurysm, of which the outflow channel supplies brain parenchyma in the territory of the parent vessel. Given the large size, unique neck, and dependent distal vessels, these aneurysms pose a technical challenge in treatment. Initial management has included surgical obliteration, but as endovascular techniques have evolved, treatment options too have expanded. In this review the authors attempt to summarize the existing body of literature on this rare entity and describe some of their institutional management strategies.

Acute thrombosis and recanalization of a ruptured anterior communicating artery aneurysm

A 35-year-old man sustained a subarachnoid hemorrhage due to the rupture of an anterior communicating artery aneurysm. A second angiogram taken 8 hours later demonstrated that the ruptured aneurysm had thrombosed spontaneously with a small residual aneurysm stump at the neck. CT scans and conventional angiograms taken 2 days later demonstrated recanalization of the aneurysm, which was successfully treated by endovascular coiling. This case differs from previous reports of spontaneously thrombosed ruptured aneurysms because the aneurysm recanalized within 2 days. Thus a thrombosed ruptured aneurysm has the potential for recanalization, and should be considered at risk of further hemorrhage.

Vascular clamp-assisted clipping of thick-walled giant aneurysms

OBJECTIVE

The prognosis of giant aneurysms remains poor despite recent advances in microneurosurgery. Thick-walled and partially calcified giant aneurysms with an atheromatic base are difficult to clip safely. Special techniques allowing reshaping of the base and ensuring the stability of clips are often needed. We present our experience with direct clipping of thick-walled giant aneurysms with the aid of the DeBakey cardiovascular clamp (Aesculap, Tuttlingen, Germany).

METHODS

Eighty-two patients with a giant aneurysm (>/=25 mm) were treated actively at the Department of Neurosurgery, Helsinki University Central Hospital, Helsinki, Finland, between 1997 and 2007. The vascular clamp technique was used in 8 of 50 patients in whom direct clipping was performed. The remaining patients were treated with bypass and trapping, trapping only, proximal occlusion, coiling, or explorative surgery.

RESULTS

The vascular clamp (DeBakey in 5 cases, Crile forceps [Medicon Medizin-Technik, Tuttlingen, Germany] in 2 cases, and Halsted-Mosquito forceps [Medicon Medizin-Technik, Tuttlingen, Germany] in 1 case) was used in 7 saccular middle cerebral artery aneurysms and 1 fusiform basilar bifurcation aneurysm. Two patients had postoperative infarctions, 1 attributable to occlusion of perforators by a clip and the other caused by clips sliding down the calcified base, occluding a major branch. Six patients had no neurological sequelae, 1 patient had transient upper limb paresis, and the patient with the occluded major branch died.

CONCLUSION

The DeBakey vascular clamp is helpful in assisting direct clipping of thick-walled giant aneurysms with a partially calcified atheromatic base. Some practical features of this instrument require further refinement.

Growth potential and response to multimodality treatment of partially thrombosed large or giant aneurysms in the posterior circulation

OBJECTIVE

This study examined the growth potential and response to multimodality treatment of partially thrombosed large or giant aneurysms in the posterior circulation.

METHODS

The 17 aneurysms arose from nonbranching sites of the vertebral artery (VA) in 6 patients and from branching sites in 11 patients (the VA-posteroinferior cerebellar artery [PICA], 3 cases; basilar artery [BA] fenestration, 1 case; BA-superior cerebellar artery [SCA], 5 cases; and BA tip, 2 cases).

RESULTS

Endovascular trapping was performed in 5 VA aneurysms at nonbranching sites, 2 VA-PICA cases with or without revascularization of the PICA, and 1 BA fenestration case. Endosaccular embolization was performed in 2 BA-SCA aneurysms as the sole treatment or after superficial temporal artery-SCA bypass for a broad-necked lesion. Surgical proximal occlusion (PO) with or without revascularization of the PICA was performed in 2 VA cases. Endovascular treatment failed to prevent growth in 1 VA-PICA case and the broad-necked BA-SCA case. Simple flow alteration by PO of 3 BA aneurysms, with gadolinium enhancement on T1-weighted images, did not prevent growth. Maximum flow reduction by various combinations of bypass (superficial temporal artery-posterior cerebral artery or superficial temporal artery-SCA) and BA PO, aimed at reducing hemodynamic stress on the neck, was tailored to 5 cases, including those refractory to PO; it achieved marked shrinkage in 2 cases and stabilization of the aneurysms in 3 cases. The aneurysms harboring neither gadolinium enhancement nor hyperintensity on fluid-attenuated inversion recovery images showed significantly lower growth potential before treatment and a lesser degree of shrinkage after tailored treatment than the remaining cases (P = 0.03 and P = 0.01, respectively). Overall, marked shrinkage was achieved in 27%, moderate shrinkage in 20%, stabilization in 47%, enlargement in 7%, and favorable outcome in 71%. Maximum flow reduction strategy for BA aneurysms tended to show higher shrinking efficacy than endovascular trapping for VA and BA aneurysms (P = 0.08).

CONCLUSION

For aneurysms at nonbranching sites, endovascular trapping may be effective, although its shrinking efficacy may be moderate. For the most formidable BA aneurysms at branching sites, maximum flow reduction may cause marked shrinkage, even of aggressive lesions.

Surgical Treatment of Giant Intracranial Aneurysms: Current Viewpoint

Objective:

Despite new endovascular techniques and technological advances in microsurgery, the treatment of giant intracranial aneurysms is still a daunting neurosurgical task. Many of these aneurysms have a large, calcified neck, directly involve parent and collateral branches, and are partly thrombosed. In this retrospective review, we focused our analysis on the indications for high-flow, extracranial-intracranial (EC-IC) bypass surgery using a saphenous vein graft.

Methods:

A series of 130 patients were treated between 1990 and 2004; 31 patients were managed endovascularly, and 99 patients were treated microsurgically (surgical clipping in 58 patients and high-flow EC-IC bypass followed by aneurysm trapping in 41 patients). We examined the patients’ clinical records and pre- and postoperative case notes for cerebral angiographic examinations. Graft patency was verified with cerebral angiography, computed tomographic angiography, Doppler ultrasound, or graft palpation.

Results:

The high-flow EC-IC bypass was used for all surgically treated prepetrous aneurysms (3 patients), intracavernous aneurysms (1 patient), intracavernous aneurysms with subarachnoid extension (23 patients), as well as for some supraclinoid aneurysms (12 of the 32 patients). It was also used for 1 of the 9 aneurysms located in the carotid bifurcation and 2 of 5 vertebrobasilar circulation aneurysms. Of the 58 patients managed by surgical clipping, 4 (6.9%) died, and 51 (94.4%) improved. Of the 41 patients managed with high-flow EC-IC bypass, 4 (9.8%) died and 34 (91.9%) improved. Graft patency at the follow-up examination was 92.7%.

Conclusion:

The “gold standard” for the treatment of giant aneurysms remains surgical clipping. When direct surgical clipping or endovascular repair is contraindicated, the high-flow EC-IC bypass is a viable surgical option.

Thrombosis, growth, recanalization, and rupture of a saccular, non-giant cerebral aneurysm

A partly thrombosed, saccular, non-giant left internal carotid artery aneurysm was discovered during an evaluation for headaches in a 75-year-old woman. A mirror-image aneurysm of the right internal carotid artery was also found. During the course of about a year, the left-sided aneurysm thrombosed, grew to giant proportions, recanalized, and ruptured. During this same time, the right-sided aneurysm remained unchanged in size or shape. Even a saccular, non-giant, thrombosed aneurysm can be potentially dangerous. Such an aneurysm requires careful monitoring. If clinically appropriate, aneurysm treatment is indicated.

An Unusual Case of a Thrombosed Giant Distal PICA Aneurysm Simulating a Large Cavernous Angioma

A 64-year-old woman was referred to our hospital with a one-month history of progressive headache. Magnetic resonance imaging (MRI) showed a hemorrhagic mass adjacent to the left inferior cerebellar hemisphere associated with a peripheral rim of signal void. Angiography demonstrated an avascular mass and the provisional diagnosis was a large cavernous angioma in the cerebellum. Intraoperative findings revealed a thrombosed giant aneurysm of the left distal posterior inferior cerebellar artery (PICA). We report an unusual case of a completely thrombosed giant aneurysm simulating a large cavernous angioma in the cerebellum. The cerebellar cisternal location of the mass may be a clue for the pre-operative diagnosis of an aneurysm.

Disappearing saccular intracranial aneurysms: do they really disappear?

SUMMARY

Evolution and natural history of cerebral aneurysms is a dynamic process. Spontaneous regression in size or complete disappearance of an aneurysm is a known phenomenon, more commonly noted in giant intracranial aneurysms. However, reappearance or regrowth of such aneurysms is rare with few anecdotal reports. We report a series of four cases including one giant aneurysm, which either disappeared or regressed on sequential angiograms. Regrowth or reappearance of two of these previously disappeared or regressed aneurysms was noted and endovascularly treated while the other two cases are being followed up. The decision to follow up was crucial considering the nature of the aneurysms to change in morphology under the influence of various hemodynamic factors.

Spontaneous thrombosis of cerebral aneurysms presenting with ischemic stroke

Complete spontaneous thrombosis of an unruptured cerebral aneurysm is a rare event that can be discovered incidentally on advanced neuroradiologic studies. Occasionally, this phenomenon may be symptomatic and can present as an ischemic stroke. The presumed mechanism is probably due to extension of the thrombi to the parent vessel, embolization of intra-aneurysmatic thrombi to distal arteries or arterial compression due to increased aneurysm mass effect. We present documented cases of this unusual entity and review the literature.

Angiographically occult, progressively expanding, giant vertebral artery aneurysm

✓Hunterian ligation is a well-known treatment for complex aneurysms not amenable to direct microsurgical clip application. After proximal parent vessel occlusion, cerebral angiography is typically used to confirm aneurysm thrombosis. The authors report on a vertebral artery (VA) aneurysm that had progressively expanded and caused brainstem compression after hunterian ligation, despite nondiagnostic findings on both conventional and computed tomography (CT) angiography at multiple time points.

This 64-year-old woman underwent hunterian ligation of a 1.8-cm VA aneurysm at the origin of the right posterior inferior cerebellar artery. An immediately postoperative conventional angiogram and follow-up CT angiograms obtained 5 and 6 years postligation confirmed complete obliteration of the lesion. Nine years after the initial surgery, however, the patient experienced neurological deterioration. Although CTs showed substantial aneurysm enlargement together with pontine compression, angiograms once again demonstrated complete right VA occlusion with no retrograde filling of the aneurysm. On reexploration, the aneurysm was effectively debulked, clipped, and obliterated. Arterial bleeding was found in the lesion neck, as was evidence of microrecanalization.

Hunterian ligation for complex aneurysms carries the risk of microrecanalization and lesion expansion despite non-diagnostic angiography. Although this ligation procedure remains a viable treatment option in carefully selected patients, an extended follow-up evaluation period may be required even when imaging suggests aneurysm obliteration.

Paediatric dissecting posterior cerebral aneurysms: report of two cases and review of the literature

INTRODUCTION

Intracranial aneurysms in the paediatric population are uncommon, accounting for 2% to 6% of all aneurysms, and spontaneous arterial dissection is rarely reported as the cause of aneurysms in children, especially in the posterior cerebral artery.

METHODS

Two cases of paediatric spontaneous posterior cerebral artery dissecting aneurysms are reported, one in a 33-month-old male child presenting with aneurysmal rupture and subarachnoid haemorrhage and the other in a 9-year-old boy with an unruptured aneurysm.

RESULTS

The first child was successfully treated by endovascular parent vessel occlusion without neurological deficit and in the second a spontaneous thrombosis of the aneurysm and its parent artery occurred associated with hydrocephalus and a favourable outcome.

CONCLUSION

Dissecting aneurysms are dynamic lesions with variable and unpredictable evolution and close follow-up and/or early treatment is warranted. Spontaneous arterial dissection is a rare, probably still under-recognized, cause of intracranial aneurysms that may be responsible for a significant number of aneurysms and spontaneous aneurysmal thromboses in children.

Progressive Growth of a Giant Dolichoectatic Vertebrobasilar Artery Aneurysm after Complete Hunterian Occlusion of the Posterior Circulation: Case Report

OBJECTIVE AND IMPORTANCE:

Dolichoectatic vertebrobasilar artery aneurysms are often extremely difficult, if not impossible, to treat with microneurosurgical clip reconstruction. As such, a Hunterian strategy via vertebral or basilar artery sacrifice is often used. We have encountered a patient in whom deliberate bilateral vertebral artery sacrifice was insufficient to avoid progressive expansion of a giant dolichoectatic vertebrobasilar artery aneurysm. On the basis of a review of the literature, we are unaware of another reported case.

CLINICAL PRESENTATION:

A 60-year-old man presented with signs and symptoms of brainstem compression from a large fusiform aneurysm involving the distal dominant vertebral and proximal basilar arteries. Results of angiographic evaluation were highly characteristic of underlying dolichoectasia.

INTERVENTION:

The patient was treated initially with staged bilateral vertebral artery occlusion and adjunctive posterior circulation revascularization. After this therapy failed, he underwent a trapping procedure and aneurysm deflation.

CONCLUSION:

Unclippable aneurysms of the vertebrobasilar system are formidable lesions. They are not uniformly treatable by direct surgical reconstruction, and their growth is not consistently stabilized by the implementation of a complete Hunterian strategy. Future developments related to the use of endovascular stent technology may offer a more successful treatment approach for patients with these complex cerebrovascular lesions.

Treatment strategy for aneurysms of the posterior cerebral artery

SUMMARY

The authors carried out a retrospective review of the records of 12 patients with aneurysms of the posterior cerebral artery (PCA). Four were asymptomatic, 1 presented with a mass effect, and 7 with a subarachnoid haemorrhage (SAH). Of the 7 ruptured aneurysms, 3 were embolized and 2 were clipped. However, 2 patients died from rebleeding before any treatment. Of the 5 unruptured aneurysms, 1 was embolized with coils but the remaining 4 have been conservatively observed. No aneurysms have ruptured during the follow-up period, and 3 have thrombosed spontaneously. According to our results, the PCA aneurysms should be treated aggressively in the early phase. Although the preservation of the anatomical integrity of the PCA should naturally be one of the prime objectives, PCA occlusion may sometimes be inevitable when treating large or fusiform aneurysms. On the other hand, conservative therapy is one of the options for the treatment of incidentally encountered unruptured ones, because these have the possibility of spontaneous thrombosis.

Thrombosis and recanalization of symptomatic nongiant saccular aneurysm

Complete thrombosis followed by recanalization of giant aneurysms is an infrequent process that has been exceptionally mentioned in relation to nongiant saccular aneurysms. A 25-year-old male presented with a right temporal hematoma and associated subarachnoid hemorrhage. Cerebral angiography revealed a small blister-like dilatation at the right middle cerebral artery bifurcation. The cerebral hematoma was surgically removed and a large thrombosed aneurysm was discovered and was wrapped. Follow-up angiography revealed complete recanalization of the aneurysm with preservation of all the arterial branches and the aneurysm was then completely occluded with detachable coils. This case provides insight into the well-known but poorly understood dynamic process of thrombosis and recanalization of cerebral aneurysms. The possible role of a cerebral hematoma in the pathogenesis of this process is discussed.

Giant intracranial aneurysms: development, clinical presentation and treatment

The natural history of giant intracranial aneurysms are grave. More than 50% of patients suffer from rupture of these aneurysms and mortality is >60% in 2 years. Modern technology and advancement of knowledge in neurosurgery and interventional neuroradiology have altered its natural course for the better. As many reports have shown, the majority of these aneurysms can be treated either by surgery or by endovascular approach, even though morbidity is higher than when treating smaller aneurysms. Certain aneurysms are more suitable to direct surgical clipping and others may have better chances of good clinical outcome by endovascular treatment. It is imperative to analyse the location, morphology, hemodynamics and circulation of normal brain of each aneurysm before the mode of treatment is decided. Needless to say, the individual patient's age, neurological and medical condition should be considered. For endovascular treatment, application of each technique, endosaccular occlusion or parent artery occlusion depends on the aneurysm location and geometry as well as its pathology. Several reports indicated that clinical outcome is better in patients treated by parent artery occlusion since it eliminates any blood flow to the aneurysm and it provides a more effective reduction of the mass effect. However, not all parent arteries can be sacrificed. In addition, endosaccular treatment is effective in preventing haemorrhage if the aneurysm is not re-canalised. It is also demonstrated that symptoms of mass effect can be reversed by endosaccular coiling. The patients who are treated this way should be closely monitored for re-canalisation.

Continued growth of and increased symptoms from a thrombosed giant aneurysm of the vertebral artery after complete endovascular occlusion and trapping: the role of vasa vasorum. Case report

A 58-year-old woman harboring a partially thrombosed giant aneurysm of the vertebral artery (VA) presented with lower cranial nerve palsies and cerebellar ataxia. The authors initially attempted to reduce the mass effect by obliterating the lumen of the aneurysm as well as by trapping of the parent artery with coils. Although there was no angiographically demonstrated evidence of filling, the aneurysm continued to enlarge. Magnetic resonance imaging revealed a marked enhancement around the packed coils close to the neck of the aneurysm. Aneurysmectomy and removal of the coils were performed and resulted in an almost complete cure of the patient's symptoms. Interestingly, at the time of resection, a marked development of vasa vasorum on the occluded VA and the neck of the aneurysm was noted. When the occluded VA was cut, there was blood oozing through the coils packed within its lumen on the side where the aneurysm lay. Histological examination showed the presence of inflammatory cells and neovascularization of a partially organized thrombus around the packed coils in both the aneurysm and occluded VA. The proliferation of vasa vasorum was also recognized histologically. This unique case provides insight into the growth mechanisms of a partially thrombosed giant aneurysm after an apparently complete occlusion by endovascular treatment, especially the role of vaso vasorum on the occluded parent artery in the dynamic process of neovascularization in the incomplete organization of thrombus around the packed coils.