A ruptured middle cerebral artery aneurysm originating from the site of anastomosis 20 years after extracranial-intracranial bypass for moyamoya disease: case report

Clinical features and endovascular treatment of ruptured peripheral cerebral aneurysms associated with moyamoya disease: an 8-year single-center experience

OBJECTIVE

Ruptured peripheral cerebral aneurysm (PPCA) associated with moyamoya disease (MMD) is rarely reported, and its optimal treatment remains controversial. This study aims to present the clinical characteristics, treatment strategies, and outcome predictors of this rare clinical entity.

METHODS

A retrospective review of patients with hemorrhagic MMD from January 2013 to December 2020 was performed. All medical records were independently compiled and reviewed.

RESULTS

Twenty-three patients were identified, 56.5% of whom were female. The mean age was 45.9 years with a peak age of onset of 51-60 years. Most patients (65.2%) developed intraventricular hemorrhage with or without intracerebral hemorrhage. These aneurysms were frequently located on the anterior (26.1%) and posterior (43.5%) choroidal arteries. Sixteen (69.6%) aneurysms were embolized and the remaining 7 (30.4%) were managed conservatively due to approach inaccessibility. Good outcomes were achieved in 82.6% of all cases, with 81.3% for embolization and 85.7% for observation. Complete occlusion was observed in all 16 aneurysms embolized. Of the conservatively treated aneurysms, 1 (14.3%) re-ruptured, 1 (14.3%) decreased in size, 2 (28.6%) disappeared, and 3 (42.8%) remained stable in size. Aneurysm rebleeding was associated with an unfavorable outcome (P = 0.026).

CONCLUSIONS

PPCA should be considered in the differential diagnosis of hemorrhagic MMD. Aneurysm rebleeding appears to be a potential predictor of poor outcome and therefore aggressive intervention should be advocated. Endovascular embolization may be safe and feasible, and conservative observation should be carefully chosen given the high risk of aneurysm re-rupture.

Treatment of moyamoya disease with intracranial aneurysm by surgical clipping combined with encephalo-duro-myo-synangiosis surgery: a case report and literature review

BACKGROUND

We report a case of 39-year-old male patient with an unruptured middle cerebral artery aneurysm associated with moyamoya disease (MMD) treated by surgical clipping combined with encephalo-duro-myo-synangiosis surgery.

CASE DESCRIPTION

A 39-year-old male patient with a history of intraventricular hemorrhage was admitted to our hospital. Preoperative digital subtraction angiography (DSA) showed the aneurysm, arising from a collateral branch of the right middle cerebral artery (RMCA), had an extremely thin neck. Also present were an occlusion of the RMCA main trunk, and moyamoya vessels. Microsurgical aneurysm clipping was performed for the aneurysm, while encephalo-duro-myo-synangiosis was performed for ipsilateral MMD. At the 4-month follow-up, the patient had recovered well and DSA indicated improved cerebral perfusion with no de novo aneurysms.

CONCLUSIONS

For ipsilateral moyamoya disease accompanied with intracranial aneurysm (IA), simultaneous surgery combining microsurgical clipping and encephalo-duro-myo-synangiosis can be a good treatment option.

Ruptured Peripheral Cerebral Aneurysms Associated With Moyamoya Disease: A Systematic Review

BACKGROUND AND PURPOSE

A ruptured peripheral cerebral aneurysm (PPCA) associated with moyamoya disease (MMD) is a rare but potentially life-threatening condition with controversial management strategies. We aim to summarize the clinical characteristics, treatment strategies, and prognostic factors of PPCAs in MMD.

METHODS

We reviewed studies published in PubMed between 1980 and 2023 and used logistic regression analysis to identify the risk factors for adverse outcomes.

RESULTS

Of 425 identified studies, 48 eligible studies involving 121 participants were included in the current study. The mean age at diagnosis was 40.8±15.1 years, with a peak age of onset between 41 and 50 years. Among the identified participants, 59.6% were female, and 55.9% presented with impaired consciousness. Aneurysms were present in the posterior (35.5%) or anterior (30.6%) choroidal arteries in 66.1% of the cases, and 71.1% of the patients presented with intraventricular hemorrhage (IVH) with or without intracerebral hematoma (ICH). The treatment strategies were embolization (28.9%), direct surgery (21.5%), revascularization (22.3%), and conservation (27.3%). Favorable outcomes were achieved in 86.8% of all cases, with 97.1% for embolization, 65.4% for direct surgery, 96.3% for revascularization, and 84.8% for conservative treatment. Aneurysm rebleeding occurred in 11 (26.8%) of 41 patients managed conservatively, leading to worse outcomes in 7 patients (63.6%). Impaired consciousness (odds ratio [OR], 8.61; 95% confidence interval [CI], 2.06-36.00) and aneurysm rebleeding (OR, 16.54; 95% CI, 3.08-88.90) independently predicted poor outcomes.

CONCLUSION

PPCA should be considered in patients with hemorrhagic MMD, particularly those with IVH with or without ICH. Endovascular and bypass treatments are recommended as first-line options, with direct open surgery as an alternative in urgent hematoma evacuation cases. Detailed preoperative planning and intraoperative technical assistance are necessary to reduce procedure-related complications. Conservative management should be selected with caution because of the high risk of rebleeding and poor outcomes. Impaired consciousness and aneurysm rebleeding appeared to be independent risk factors for adverse prognoses. We emphasize that treatment selection should be personalized, and the potential benefits should be weighed against the associated risks.

Hemodynamic Effects of Tortuosity and Stenosis in Superficial Temporal Artery-Middle Cerebral Artery Bypass for Moyamoya Disease

BACKGROUND

Superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery has been widely adopted in treating moyamoya disease (MMD). Geometric variations including high tortuosity and stenosis exist in many cases, but the hemodynamic effects have not been comprehensively evaluated. We aim to evaluate the hemodynamic effects of bypass geometry variations based on patient-specific data.

METHODS

In total, 17 patients with MMD who underwent STA-MCA bypass surgery with highly tortuous bypass geometry were included. For each patient, the original 3-dimensional structure of STA-MCA bypass was reconstructed from clinical imaging data. The bypass structure was virtually improved by removing the tortuosity and stenosis. Computational fluid dynamics simulation was performed on both bypass structures under identical patient-specific condition. The simulated hemodynamic parameters of the bypass and its distal branches were compared between the original and virtually improved bypass geometries in all cases using paired t-test or Wilcoxon signed-rank test. The changes of hemodynamic parameters were compared between the cases with and without mild-to-moderate stenosis (44.0-70.3% in diameter) in the bypass using t-test or Mann-Whitney U test.

RESULTS

The virtual improvement of bypass geometry significantly increased the flow rate of the bypass and its distal branches (P < 0.05) and decreased the transcranial flow resistance (P < 0.05). The hemodynamic changes in cases with stenosis removal were significantly greater than those without stenosis (P < 0.05).

CONCLUSIONS

High tortuosity and stenosis can significantly change the hemodynamics of STA-MCA bypass, and the optimization of bypass geometry deserves further consideration.

Spontaneous occlusion of ruptured microaneurysm formed on postoperative transosseous anastomosis after indirect revascularization in a patient with moyamoya disease

A 40-year-old female with a history of ischemic moyamoya disease treated with indirect revascularization at ages 12 and 25 years presented with a sudden severe headache. Imaging studies revealed focal parenchymal hemorrhage and acute subdural hematoma, confirming a microaneurysm formed on the postoperative transosseous vascular network as the source of bleeding. Conservative management was performed, and no hemorrhage recurred during the 6-month follow-up period. Interestingly, follow-up imaging revealed spontaneous occlusion of the microaneurysm. However, due to the rarity of this presentation, the efficacy of conservative treatment remains unclear. Further research on similar cases is warranted.

Detethering the superficial temporal artery: Application to tension free superficial temporal artery-middle cerebral artery bypasses

Extracranial-intracranial bypass has been shown to be effective in the surgical treatment of moyamoya disease, complex aneurysms, and tumors that involve proximal vasculature in carefully selected patients. Branches of the superficial temporal artery (STA) are used commonly for the bypass surgery; however, an appropriate length of the donor vessel must be harvested to avoid failure secondary to anastomotic tension. The goal of this cadaveric study was to investigate quantitatively operative techniques that can increase the STA length available to facilitate tension-free STA-middle cerebral artery (MCA) bypass. We conducted a cadaveric study using a total of 16 sides in eight cadavers. Measurements of the STA trunk with its frontal branch (STAfb) were taken before and after skeletonization and detethering of the STA with the STAfb and mobilization of the parietal branch of the STA. A final measurement of the STA with the STAfb was taken for the free length gained toward visible proximal cortical branches of the MCA. Paired student's t-tests were used to compare the mean length before and after mobilization and unpaired t-tests to analyze according to laterality. The mean length of the STA with the STAfb was 9.0 cm prior to modification. After skeletonization and mobilization, the mean lengths increased significantly to 10.5 and 11.3 cm, respectively (p < 0.05). Especially in the cases that had the coiled and tortuous STA, skeletonization was considerably effective to increase the length of the STA with the STAfb. After simulating a bypass by bringing the STAfb to the recipient MCA site, the mean extended length of the STA with the STAfb was 3.0 cm. There were no statistically significant differences between sides in all measurements. We report a significant increase in the mean STA length available (3.0 cm) following skeletonization and mobilization. Clinical applications of the extended length of the STA with the STAfb may facilitate tension-free STA-MCA bypasses and improve outcomes. Further studies are needed in a clinical context.

Transcallosal, transchoroidal clipping of a hypothalamic collateral vessel aneurysm in Moyamoya disease

Peripheral collateral vessel aneurysms in Moyamoya disease (MMD) remain difficult to treat due to their deep location, small size, and vascular fragility. We report the case of an aneurysm localized in the hypothalamus, which was rapidly increasing in size with repeated hemorrhage despite revascularization surgery. Aneurysm clipping was performed to prevent further progress and rerupture with favorable outcome. To our best knowledge, this is the first description of a hypothalamic aneurysm in MMD being clipped via a transcallosal, transchoroidal approach through the third ventricle.

Location-based treatment of intracranial aneurysms in moyamoya disease: a systematic review and descriptive analysis

We conducted a systematic review of the literature to evaluate the efficacy of various treatment modalities for intracranial aneurysms (IA) in patients with moyamoya disease (MMD) based on anatomical location of IA. A comprehensive review of studies documenting single cases or series of MMD patients with concomitant IA was conducted. Aneurysms were classified into two primary anatomical categories: those of the Circle of Willis (CoW) and those of peripheral "moyamoya" collateral vessels. Conservative, endovascular, and open surgical treatment modalities and their outcomes between each anatomical subgroup were descriptively compared. A total of 124 studies consisting of 275 patients with 313 IA were included. Of all IA, 59.6% were located on CoW vessels, 33.7% on peripheral vessels, and 6.7% in "other" locations. Of all CoW IA, 87.2% treated with endovascular techniques had no or minimal deficit at follow-up as compared with 56.7% of those treated with open surgery. Ninety-five percent of patients with peripheral aneurysms treated with endovascular therapy had no or minimal deficit, in contrast to open surgery (69.6%). Of peripheral IA treated conservatively with or without revascularization, 65.7% had spontaneous resolution as compared with 12.0% IA of the CoW. Our results support the use of endovascular techniques for direct treatment of both CoW and peripheral IA. Aneurysms of peripheral vessels respond well to indirect treatment through surgical revascularization as opposed to CoW aneurysms. The quality of evidence is limited due to heterogeneity of included studies and IA management in MMD patients should be considered in a case-specific manne.

The prospects and pitfalls in the endovascular treatment of moyamoya disease-associated intracranial aneurysms

Moyamoya disease (MMD) is characterized by progressive stenosis or occlusion of the distal internal carotid artery and simultaneous formation of collateral vasculature. The fragile alteration and increased hemodynamic stress in the intra- and extracranial vasculature would conjointly result in the formation of intracranial aneurysms in MMD patients. According to our classification, the MMD-associated aneurysms are divided into the major artery aneurysms (MAAs) and non-MAAs. The non-MAAs are further subdivided into the distal choroidal artery aneurysms, moyamoya vessel aneurysms, transdural collateral aneurysms, and anastomosis aneurysms. Currently, endovascular treatment (EVT) has become the main stream for the MMD-associated aneurysms. There is no difference to EVT for the MMD-associated MAAs of the non-stenosed major arteries with that in the non-MMD patients. While it is a big challenge to perform EVT for MMD-associated aneurysms in the stenosed arteries. Generally speaking, the parent arteries of the non-MAAs are slim, and super-selective catheterization is technically difficult. Most of the times, parent artery occlusion with liquid embolic agents or coils can only be performed. The vasculature in MMD patients is fragile; perioperative management and meticulous intraoperative manipulation are also very important to avoid complications during EVT. In spites of the complications, the EVT can bring good outcome in selected cases of MMD-associated aneurysms.

Rapid Development of an Aneurysm at the Anastomotic Site of a Superficial Temporal Artery to Middle Cerebral Artery Bypass: Case Report and Literature Review

BACKGROUND

Direct extracranial to intracranial (EC-IC) bypass is a valuable treatment option for symptomatic occlusive cerebrovascular disease and complex intracranial aneurysms. Aneurysm formation at or near the anastomotic site is a rarely reported phenomenon, and the pathophysiology and appropriate management of such de novo aneurysms are not clear.

CASE DESCRIPTION

Here we present the case of a superficial temporal to middle cerebral artery (STA-MCA) anastomosis that was complicated by aneurysm formation at the anastomotic site. This was treated with microsurgical clipping with preservation of the bypass. Pathologic analysis of the lesion was consistent with a pseudoaneurysm. We provide a literature review of this phenomenon, which is most often associated with low-flow STA-MCA bypasses, including review of the pathologic findings associated with it.

CONCLUSION

Pseudoaneurysm formation at the site of an EC-IC bypass is a rare phenomenon that should be recognized and treated to prevent further growth and rupture.

Revascularization of the anterior cerebral artery by Y-shaped superficial temporal artery interposition graft for the treatment of a de novo aneurysm arising at the site of A3-A3 bypass: technical case report

The most frequently used option to reconstruct the anterior cerebral artery (ACA) is an ACA-ACA side-to-side anastomosis. The long-term outcome and complications of this technique are unclear. The authors report a case of a de novo aneurysm arising at the site of A3-A3 anastomosis. A 53-year-old woman underwent A3-A3 side-to-side anastomosis for the treatment of a ruptured right A2 dissecting aneurysm. At 44 months after surgery, a de novo aneurysm developed at the site of anastomosis. The aneurysm developed in the front wall of the anastomosis site, and projected to the anterosuperior direction. A computational fluid dynamics (CFD) study showed the localized region with high wall shear stress coincident with the pulsation in the front wall of the anastomosis site, where the aneurysm developed. A Y-shaped superficial temporal artery (STA) interposition graft was used successfully to reconstruct both ACAs, and then the aneurysm was trapped. To the authors' knowledge, this is the first case of a de novo aneurysm that developed at the site of an ACA-ACA side-to-side anastomosis. A CFD study showed that hemodynamic stress might be an underlying cause of the aneurysm formation. A Y-shaped STA interposition graft is a useful option to treat this aneurysm. Long-term follow-up is necessary to detect this rare complication after ACA-ACA anastomosis.

Navigation-guided clipping of a de novo aneurysm associated with superficial temporal artery-middle cerebral artery bypass combined with indirect pial synangiosis in a patient with moyamoya disease

De novo aneurysms associated with superficial temporal artery (STA)-middle cerebral artery (MCA) bypass are an extremely rare complication of direct revascularization surgery for moyamoya disease (MMD). The basic pathology of MMD includes fragility of the intracranial arterial wall characterized by medial layer thinness and waving of the internal elastic lamina. However, the incidence of newly formed aneurysms at the site of anastomosis currently remains unknown. Among 317 consecutive direct/indirect combined revascularization surgeries performed for MMD, we encountered a 52-year-old woman manifesting a de novo aneurysm adjacent to the site of anastomosis 11 years after successful STA-MCA bypass with encephalo-duro-myo-synangiosis (EDMS). Although the patient remained asymptomatic, the aneurysm gradually increased in diameter to more than 6 mm with the formation of a daughter sac, and a computational fluid dynamic study revealed low wall shear stress at the aneurysm dome. The patient underwent microsurgical clipping of the aneurysm using a neuro-navigation system that permitted the minimally invasive dissection of the temporal muscle flap used for EDMS at the site of the aneurysm without affecting pial synangiosis. The aneurysm was successfully occluded using a titanium clip without complications. The postoperative course was uneventful, and the patient was discharged without neurological deficits. De novo aneurysms associated with STA-MCA bypass for MMD may be safely treated with microsurgical clipping, even in cases initially managed by a combined revascularization procedure that includes complex pial synangiosis. We recommend the application of the neuro-navigation system for the maximum preservation of pial synangiosis during this procedure.

De novo giant posterior cerebral artery aneurysm developing 25 years after basilar bifurcation aneurysm treatment using a Drake tourniquet: case report and implications for aneurysm follow-up

The objective of this paper was to report a rare complication of basilar artery (BA) tourniquet treatment of a giant basilar tip aneurysm, and to discuss possible causes for the formation of a de novo giant posterior cerebral artery (PCA) aneurysm. A 34-year-old woman underwent satisfactory treatment of a ruptured giant basilar bifurcation aneurysm by BA ligation (Drake tourniquet) in 1985. She presented 25 years later with a new aneurysm in the left PCA, successfully treated by coil embolization. To the authors' knowledge, this is the first case of de novo aneurysm formation on a PCA, and the first de novo aneurysm reported as a complication of BA ligation therapy by Drake tourniquet. Long-term follow-up is necessary in patients with treated cerebral aneurysms, particularly those occurring in young patients, those with multiple aneurysms, those with complex posterior circulation aneurysms, and those undergoing flow diversion or flow-altering therapies.

De Novo Aneurysm Associated with Superficial Temporal Artery to Middle Cerebral Artery Bypass: Report of Two Cases and Review of Literature

BACKGROUND

De novo aneurysm formation has been reported as a rare complication of superficial temporal artery (STA) to middle cerebral artery (MCA) bypass surgery.

CASE DESCRIPTION

The first patient with intracerebral hemorrhage had a ruptured de novo aneurysm arising from the recipient MCA at 6 years after undergoing STA-MCA bypass for hemispheric hemodynamic insufficiency. In the second case, an enlarging unruptured STA aneurysm was detected by follow-up magnetic resonance angiography at 8 years after the patient underwent STA-MCA bypass for moyamoya disease. Both patients were successfully treated by surgical clipping.

CONCLUSIONS

Persistent hemodynamic stress with hypertension in an artificial T-shaped vasculature and traumatic injury during surgical manipulation are the most important causes for de novo aneurysms after STA-MCA bypass. Follow-up magnetic resonance and computed tomography angiography examinations, along with appropriate blood pressure control, are recommended for patients who have undergone STA-MCA bypass surgery.

Progress on Complications of Direct Bypass for Moyamoya Disease

Moyamoya disease (MMD) involves progressive occlusion of the intracranial internal carotid artery resulting in formation of moyamoya-like vessels at the base of the brain. It can be characterized by hemorrhage or ischemia. Direct vascular bypass is the main and most effective treatment of MMD. However, patients with MMD differ from those with normal cerebral vessels. MMD patients have unstable intracranial artery hemodynamics and a poor blood flow reserve; therefore, during the direct bypass of superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis, perioperative risk factors and anesthesia can affect the hemodynamics of these patients. When brain tissue cannot tolerate a high blood flow rate, it becomes prone to hyperperfusion syndrome, which leads to neurological function defects and can even cause intracranial hemorrhage in severe cases. The brain tissue is prone to infarction when hemodynamic equilibrium is affected. In addition, bypass vessels become susceptible to occlusion or atrophy when blood resistance increases. Even compression of the temporalis affects bypass vessels. Because the STA is used in MMD surgery, the scalp becomes ischemic and is likely to develop necrosis and infection. These complications of MMD surgery are difficult to manage and are not well understood. To date, no systematic studies of the complications that occur after direct bypass in MMD have been performed, and reported complications are hidden among various case studies; therefore, this paper presents a review and summary of the literature in PubMed on the complications of direct bypass in MMD.

Rapid De Novo Aneurysm Formation after Rathke Cleft Cyst Rupture

BACKGROUND

Spontaneous rupture of a Rathke cleft cyst is very rare, and rapid de novo aneurysm formation associated with pituitary apoplexy is rare.

CASE DESCRIPTION

A 66-year-old woman experienced severe left temporal pain. Magnetic resonance imaging showed a Rathke cleft cyst, and transsphenoidal surgery was planned. However, the patient suddenly developed severe headache, vomiting, visual disturbance, and a lowered level of consciousness about 3 weeks after the first onset. The clinical course and neuroradiologic characteristics suggested Rathke cleft cyst rupture. The patient received hormone replacement, and the visual abnormalities resolved. However, subsequent neuroradiologic evaluation demonstrated that a de novo aneurysm in the cavernous sinus portion of the internal carotid artery had formed within 8 days after rupture of the Rathke cleft cyst. This de novo aneurysm was not apparent on initial magnetic resonance angiography.

CONCLUSIONS

This case features a rare clinical presentation of rapid de novo aneurysm formation after Rathke cleft cyst rupture. The severe inflammation around the vasculature after rupture of the Rathke cleft cyst might have been involved in aneurysm formation.

Repeated de novo aneurysm formation after anastomotic surgery: Potential risk of genetic variant RNF213 c.14576G>A

Background:

De novo aneurysm formation after intracranial anastomotic surgery is a relatively rare complication with fewer than 20 reported cases, and the mechanism is still unclear.

Case Description:

A 63-year-old male treated for symptomatic internal carotid artery occlusion developed de novo aneurysms twice after anastomoses first of the superficial temporal artery-middle cerebral artery and second of the external carotid artery-radial artery-middle cerebral artery over a 10-year period. The first de novo aneurysm was successfully resected with pathological diagnosis of true aneurysm. The second de novo aneurysm thrombosed naturally after gradual growth. Genetic testing of the patient revealed the c.14576G>A (p.R4859K) variant in ring finger protein 213, which is a susceptibility gene for moyamoya disease.

Conclusions:

This genetic variant was probably involved in the repeated de novo aneurysm formation, and this case represents a rare phenotype of the genetic variant.

Treatment strategies for aneurysms associated with moyamoya disease

The treatment of aneurysms associated with moyamoya disease (MMD) is difficult for neurosurgeons, and little is known of strategy options. This report constitutes a comprehensive review of the literature. We summarize the known treatments and their clinical outcomes according to the site of the aneurysm: in major arteries, peripheral arteries, moyamoya vessels, meningeal arteries, or at the site of anastomosis. The literature review indicates that the treatment of MMD-associated aneurysms varies according to the site of the aneurysm and its hemodynamic characteristics. In particular, the treatment for basilar tip aneurysms remains challenging, since both endovascular embolization and direct clipping are difficult. The potential risk for ischemia should be considered in selecting endovascular or surgical approaches. Revascularization surgery, which is important for the treatment of MMD, also determines the clinical treatment outcome of aneurysms associated with MMD.

Rupture of de novo anterior communicating artery aneurysm 8 days after the clipping of ruptured middle cerebral artery aneurysm

Rapidly developed de novo aneurysm is very rare. We present a rapidly developed and ruptured de novo anterior communicating aneurysm 8 days after the rupture of another aneurysm. This de novo aneurysm was not apparent in the initial 3-dimensional computed tomography and digital subtraction angiography. We reviewed the literature and discussed possible mechanisms for the development of this de novo aneurysm.

Ruptured de novo aneurysm arising at a site remote from the anastomosis 14 years after superficial temporal artery-middle cerebral artery bypass: a case report

BACKGROUND AND IMPORTANCE

The long-term outcome of superficial temporal artery (STA)-middle cerebral artery (MCA) bypass is unclear. We report a very rare case of a de novo aneurysm after bypass surgery.

CLINICAL PRESENTATION

A 57-year-old woman who underwent STA-MCA bypass and internal carotid artery aneurysm treatment 14 years earlier developed a subarachnoid hemorrhage and a temporal lobe hematoma on the same side as the anastomosis. Angiography showed excellent patency of the STA bypass and a ruptured de novo saccular aneurysm at a site remote from the anastomosis. Neck clipping and hematoma evacuation were performed on the second day, and postoperative angiography showed complete aneurysmal clipping. The aneurysm was considered to be caused by hemodynamic stress because it was remote from the anastomosis and had developed after a prolonged interval of 14 years; furthermore, the aneurysm projected because of the hemodynamic force of the STA perfusion.

CONCLUSION

This is the first reported case of a de novo MCA aneurysm that developed at a site remote from STA-MCA anastomosis because of hemodynamic force. Therefore, long-term control of blood pressure and repeated imaging examination should be performed to confirm patency and to identify aneurysm formation after STA-MCA bypass.

De novo basilar artery aneurysm formation after placement of a Wingspan stent

Report the de novo formation of an aneurysm after wingspan placement and describe the treatment modality. We report a patient with symptomatic basilar stenosis who underwent placement of a wingspan stent. On 9-month follow-up, the patient was found to have a new 5-mm aneurysm adjacent to the proximal tines of the stent. The patient subsequently underwent placement of an enterprise stent and coils for aneurysm occlusion. We reviewed the literature and discussed possible etiologies for the development of this unique de novo aneurysm.

Intracerebral hemorrhage from a ruptured aneurysm at the site of anastomosis 27 years after superficial temporal artery-middle cerebral artery bypass

A 77-year-old female presented with a very rare case of intracerebral hemorrhage (ICH) from a ruptured aneurysm at the site of the anastomosis 27 years after superficial temporal artery-middle cerebral artery (STA-MCA) bypass manifesting as sudden onset of unconsciousness and right hemiparesis. Computed tomography (CT) on admission demonstrated massive ICH in the left frontoparietal region. Magnetic resonance angiography showed good patency of the anastomosis and no obvious aneurysm, but three-dimensional CT (3D-CT) angiography revealed a small aneurysm at the site of the left STA-MCA anastomosis. Emergency evacuation of the hematoma was performed, and the aneurysm was trapped and resected after ligation. After the operation, she continued to exhibit deep consciousness disturbance. Unfortunately, her general condition grew steadily worse and she died 3 months later. Patients who undergo STA-MCA anastomosis should be carefully followed up by periodical imaging examinations. 3D-CT angiography is very useful to detect aneurysm formation at the anastomosis site.

Intracerebral hemorrhage caused by rupture of a giant aneurysm complicating superficial temporal artery-middle cerebral artery anastomosis for moyamoya disease

INTRODUCTION

Aneurysm formation at the anastomosis site after extracranial-intracranial (EC-IC) bypass surgery for major arterial occlusion or stenosis due to atherosclerosis has only been reported a few times previously. However, no case describing the formation of a giant aneurysm after EC-IC bypass surgery has been reported to date. Additionally, this complication associated with moyamoya disease is extremely rare, and only one case has been reported so far.

CLINICAL REPORT

We report a case of a 51-year-old woman having a rare complication of intracerebral hemorrhage due to rupture of a giant aneurysm that developed after superficial temporal artery-middle cerebral artery anastomosis for the treatment of moyamoya disease.

CONCLUSION

To the best of our knowledge, this is the first reported case of a giant aneurysm, also the largest so far occurring after EC-IC bypass surgery and the second reported case of a rupture of an aneurysm formed after bypass surgery for moyamoya disease.

Disappearance of a middle cerebral artery aneurysm associated with Moyamoya syndrome after revascularization in a child: case report

INTRODUCTION

Pediatric Moyamoya disease is rarely associated with intracranial aneurysms. We report a case of a 7-year-old girl with an antecedent of persistent craniopharyngeal canal, who presented with a history of choreiform movements.

MATERIALS AND METHODS

A Moyamoya disease was found with an unruptured left middle cerebral artery aneurysm on her first angiography. Conservative treatment was chosen for the aneurysm and she underwent indirect revascularization by encephalosynangiosis using the multiple bur-hole technique for her Moyamoya disease. Abnormal movements were improved. Control angiogram at 6 months showed development of intracranial-extracranial anastomoses with complete resolution of the aneurysm. Aneuryms including the major arteries of the basal arterial circle occur as a by-product of the high velocity and blood flow secondary to the arterial stenosis. Blood flow modification after revascularization often lead to spontaneous regression and disappearance of these aneurysms.

CONCLUSION

Therefore, a conservative treatment of these proximal aneurysms must be chosen after encephalosynangiosis.

De novo aneurysm formation on middle cerebral artery branches adjacent to the anastomotic site of superficial temporal artery-middle cerebral artery bypass surgery in two patients: technical case report

OBJECTIVE

Aneurysm formation is a complication of superficial temporal artery-middle cerebral artery bypass surgery occurring as pseudoaneurysms caused by technical failure, but also as true aneurysms discovered after long-term follow-up.

CLINICAL PRESENTATION

A 53-year-old woman presented with a left internal carotid artery cavernous aneurysm manifesting as double vision. Superficial temporal artery-middle cerebral artery bypass, internal trapping of the internal carotid artery, and embolization were performed. Three years later, angiography disclosed a distal middle cerebral artery aneurysm. A 70-year-old man who had undergone right superficial temporal artery-middle cerebral artery bypass after internal carotid artery occlusion died of subarachnoid hemorrhage from a ruptured anterior spinal artery aneurysm 21 years later. Angiography and postmortem examination revealed de novo aneurysm formation on a middle cerebral artery branch adjoining the anastomotic site. Both patients had hypertension and multiplicity of aneurysms.

INTERPRETATION

Both cases were de novo true aneurysms caused by hemodynamic stress because of saccular to fusiform shape, location extending to the middle cerebral artery, high perfusion pressure, projection along the hemodynamic stress, and presence of common risk factors.

CONCLUSION

Bypass surgery is increasingly performed in patients with complicated aneurysms if sacrifice or temporary occlusion of any major vessel is required. Therefore, de novo aneurysm formation may not be rare in patients with risk factors such as hypertension or multiple aneurysms. Extended follow-up examination is required in such patients.

RECURRENT SUBARACHNOID HEMORRHAGE CAUSED BY A DE NOVO BASILAR TIP ANEURYSM DEVELOPING WITHIN 8 WEEKS AFTER CLIPPING OF A RUPTURED ANTERIOR COMMUNICATING ARTERY ANEURYSM

OBJECTIVE

Well-documented case reports of the rapid formation and rupture of de novo aneurysms of the posterior circulation are rare.

CLINICAL PRESENTATION

We report a patient with subarachnoid hemorrhage caused by an aneurysm of the anterior communicating artery that was clipped consecutively. Forty-four days after the initial subarachnoid hemorrhage, the patient experienced a second subarachnoid hemorrhage after the rupture of a newly grown aneurysm of the basilar tip. Between the two hemorrhages, transcranial Doppler sonography and neuroimaging revealed a fulminant generalized vasospasm.

INTERVENTION

To our knowledge, this is the first report of the rapid development and rupture of a de novo aneurysm of the posterior circulation after the rupture of an initial aneurysm of the anterior circulation.

CONCLUSION

We review the pertinent literature and discuss possible reasons for the development and rupture of this second aneurysm.

Primary Percutaneous Transluminal Angioplasty for Early Moyamoya Disease

Moyamoya disease is a progressive steno-oclusive arteriopathy of the circle of Willis that manifests on cerebral angiography with a characteristic net of vessels at the base of the brain representing collateralization. Described initially in Japan where children present with cerebral ischemia and adults with hemorrhagic stroke, it was recognized to have a more benign course in the United States, mainly causing cerebral ischemic events in young adults. Medical treatment is not intended to stop the progression of the disease and surgery is not exempt of risks. We present a patient with early moyamoya disease in the United States in whom primary transluminal angioplasty, a less invasive procedure, was performed to treat the stenotic arteriopathy with good immediate and sustained clinical and angiographic results, without evidence of restenosis at the site of angioplasty 2 years later.