Ruptured Pseudoaneurysm after Gamma Knife Surgery for Vestibular Schwannoma

Ruptured aneurysms of anterior inferior cerebellar artery (AICA) after radiotherapy for vestibular schwannoma (VS) are rare, and no definite treatment has been established for distal AICA pseudoaneurysms. We describe a 61-year-old man who underwent Gamma Knife surgery (GKS) for left VS. Follow-up magnetic resonance imaging (MRI) revealed partial regression of the tumor. Twelve years after GKS, he suffered from subarachnoid hemorrhage. Initial angiogram showed no vascular lesions; second left vertebral angiogram, 10 days after admission, demonstrated a pseudoaneurysm in the lateral pontine segment of the left AICA. The proximal portion of the AICA was occluded by a coil. Postoperative MRI revealed an infarction on the left side of the pons and brachium pontis. Although the patient suffered from mild postoperative cerebellar ataxia and facial and abducens nerve palsy, he was discharged 1 month postoperatively requiring no assistance with activities of daily living. Twelve months later, he recovered satisfactorily with a modified Rankin Scale grade of 1, and no recanalization of the aneurysm was found on MR angiography. Endovascular parent artery occlusion for ruptured aneurysms at distal AICA carries the risk of brain stem infarction, but should be considered when no other option is available such as after radiotherapy for VS.     

Ruptured intracranial aneurysm following gamma knife surgery for acoustic neuroma

Summary A-63-year-old woman underwent gamma knife surgery (GKS) for acoustic neuroma. Six years later, she suffered sudden onset of severe headache followed by a disturbance of consciousness and subarachnoid haemorrhage due to a ruptured aneurysm originating from the distal anterior inferior cerebellar artery. The aneurysm was not located at a branching site and was included within the radiation field. The aneurysm was treated by endovascular embolization, and now, 15 months later, the patient has recovered satisfactorily. This is the first report of aneurysm formation following GKS for acoustic neuroma.     

Intrameatal thrombosed anterior inferior cerebellar artery aneurysm mimicking a vestibular schwannoma

Aneurysms of the anterior inferior cerebellar artery (AICA) are a rare entity. Purely intrameatal aneurysms are even rarer. The authors report an intrameatal thrombosed AICA aneurysm mimicking a vestibular schwannoma that was treated by resection and end-to-end anastomosis. This 22-year-old man presented with acute hearing loss, vertigo, and moderate facial palsy. Magnetic resonance imaging showed an atypical intrameatal lesion with dilation of the internal auditory canal. Microsurgical inspection via a retrosigmoid approach and drilling of the posterior wall of the internal auditory canal revealed a thrombosed AICA aneurysm. The aneurysm was excised, and an end-to-end suture was performed to restore AICA continuity. Intraoperative indocyanine green videoangiography as well as postoperative digital substraction angiography showed a good revascularization. Intrameatal AICA aneurysms may present with symptoms similar to vestibular schwannomas. End-to-end reanastomosis after aneurysm resection is a treatment option when clipping is impossible.     

Intratumoral hemorrhage after remote subtotal microsurgical resection and gamma knife radiosurgery for vestibular schwannoma

Summary Our report describes the occurrence of intratumoral hemorrhage in a vestibular schwannoma, which was treated with microsurgical resection thirteen years and gamma knife surgery (GKS) more than two years prior to the event. Although rare, it is apparent that bleeding into a vestibular schwannoma remains a possibility, even after the tumor has responded favorably to GKS. Long-term followup of patients with vestibular schwannoma who have been treated with GKS is advisable to assess treatment response and to detect adverse events (e.g. hemorrhage) suspected on clinical grounds.     

Acoustic schwannoma presenting as subarachnoid hemorrhage due to ruptured contact aneurysm

The authors report a rare combination of aneurysm and acoustic schwannoma in a 66-year-old housewife, who developed subarachnoid hemorrhage from a ruptured aneurysm arising from an arterial branch of the posterior inferior cerebellar artery on the tumor capsule. Association of aneurysm and cerebellopontine angle schwannoma is extremely rare, and there has been no report of subarachnoid hemorrhage due to ruptured contact aneurysm, although previous reports indicated a small number of acoustic schwannomas accompanying hematomas in and around tumors.     

Distal superior cerebellar artery aneurysm

A case of an aneurysm arising from the distal portion of the superior cerebellar artery is described. Angiography showed an aneurysm near the internal auditory canal, arising from the medial branch of the superior cerebellar artery associated with hypoplasia of the ipsilateral anterior inferior cerebellar artery and posterior inferior cerebellar artery.     

Aneurysm of the distal anterior inferior cerebellar artery at the medial branch: a case report and review of the literature.

BACKGROUND: Distal aneurysms of the anterior inferior cerebellar artery (AICA) are rare. Most have been located at the cerebellopontine angle. Only three cases, including ours, located in the medial branch of the AICA have been reported in the literature. METHODS: A 55-year-old female presented with epilepsy that she experienced for the first time. Computed tomography and magnetic resonance imaging revealed no abnormality. Digital subtraction angiography (DSA) disclosed a rare aneurysm at the medial branch of the distal anterior inferior cerebellar artery. In the blood workup on her admission, a mild inflammatory sign was found, and bacterial aneurysm was suggested as the presumptive differential diagnosis. Repeated DSA was performed 3 months after admission, but the aneurysm did not disappear. She then underwent a suboccipital craniotomy in the prone position. RESULTS: The aneurysm was clipped and partially resected for the pathological examination. Histologic examination revealed a true aneurysm. She was discharged without neurological deficit. CONCLUSIONS: In this report, we summarize the previous cases and discuss the location and clinical manifestations of aneurysms of the AICA through a review of the literature.     

Endovascular treatment of AVM-associated aneurysm of anterior inferior cerebellar artery through persistent primitive hypoglossal artery

We present a patient with the combination of persistent primitive hypoglossal artery and the origin of left common carotid artery from the brachiocephalic trunk, who had subarachnoid haemorrhage caused by a ruptured aneurysm. The aneurysm was on distal anterior inferior cerebellar artery which was a feeder to cerebellar arterio-venous malformation.     

Repeated treatment of vestibular schwannomas after gamma knife radiosurgery

Purpose  When gamma knife radiosurgery (GKS) does not achieve control of the growth of a tumour, the need to repeat treatment is considered. The results and risks of repeat treatment of patients with a vestibular schwannoma were reviewed to assess its efficacy and safety. Methods  Between 1992 and 2001, we treated 351 patients with a vestibular schwannoma by GKS, control of the growth of the tumour was not achieved in 32. 26 patients underwntrepeat GKS and five patients had an open microsurgical operation and one stereotactic aspiration of a tumour cyst. Results  Twenty-four of 26 patients were followed up after the repeat GKS for a median of 43 months. 15 tumours became smaller, seven remained unchanged and two enlarged. After the second GKS one patient’s hearing deteriorated, one developed facial weakness and three facial spasms. One patient required insertion of ventriculo-peritoneal drainage. An operation to radically resect the tumour was performed in five patients after the first GKS and for a subtotal removal in one after repeated GKS. Conclusions  In the small proportion of patients (9%) in whom initial GKS does not control the growth of a vestibular schwannoma, most can be controlled by further GKS with a very low risk of a complications.     

Development of unusual collateral channel from the posterior meningeal artery after endovascular proximal occlusion of the posterior inferior cerebellar artery

A 38-year-old man presented with a dissecting aneurysm of the left proximal posterior inferior cerebellar artery (PICA) manifesting as Wallenberg's syndrome. The patient was treated by endovascular occlusion of the aneurysm and parent artery. Immediately after the treatment, the PICA territory was supplied by collateral circulation via the ipsilateral anterior inferior cerebellar artery. Seven days later, endogenous revascularization of the distal PICA territory had occurred via collateral circulation from the posterior meningeal artery (PMA). This unusual collateral circulation was thought to occur through a pre-existing anastomotic channel between the primitive vessels of the PICA and the PMA during subclinical hypoperfusion of the distal PICA territory. This unusual case demonstrates the potential for delayed development of collateral circulation from the PMA to the PICA territory.     

Surgical Management of PICA Aneurysm and Incidental Facial Nerve Schwannoma: Case Report.

We report a patient with a posterior inferior cerebellar artery (PICA) aneurysm and an incidental facial nerve schwannoma at the cerebellopontine angle (CPA). A 46-year-old woman presented with the sudden onset of a severe headache, nausea, and vomiting. She had no other abnormal neurological symptoms and signs. Computed tomography (CT) showed hemorrhage in the fourth ventricle. Cerebral angiography demonstrated an aneurysm arising from the tonsillomedullary segment of the left PICA. A facial nerve schwannoma was incidentally found as the aneurysm was being clipped. The aneurysm was clipped via a left transcondylar approach. Subsequently, the schwannoma (2 x 3 x 2 mm) was resected from the facial nerve fascicles, and the facial nerve was preserved. Postoperatively, the patient developed mild to moderate dysfunction of the facial nerve (House-Brackmann grade III [H-B III]) but her hearing was intact. Both a facial nerve schwannoma involving the CPA and an aneurysm involving the PICA can be managed through the transcondylar approach. An asymptomatic facial nerve schwannoma can be resected safely with minimal facial nerve dysfunction.     

Aneurysm of the distal anterior inferior cerebellar artery unrelated to the cerebellopontine angle: case report

This is a case report of an unusual aneurysm of the distal anterior inferior cerebellar artery. A 44-year-old woman had a severe frontal headache and vomiting of sudden onset. On the day after admission, the patient began to demonstrate nuchal rigidity and difficulty with upward gaze bilaterally. There were no complaints at this time suggestive of a syndrome of the cerebellopontine angle. A computed tomographic scan revealed an intraventricular hemorrhage of the 3rd and 4th ventricles; however, multiple attempts at four-vessel angiography were required before an aneurysm could be demonstrated. On the 28th hospital day, a suboccipital craniectomy using the retromastoid approach in the lateral position was performed. A saccular aneurysm with a surrounding hematoma in the distal anterior inferior cerebellar artery was found and clipped. The operative findings revealed that the aneurysm was unrelated to the cerebellopontine angle. After surgery, the patient had an uneventful recovery and complete resolution of symptoms.     

Multiple,peripheral aneurysms of the anterior inferior cerebellar artery

Summary In this case report, a 49-year-old woman developed subarachnoid hemorrhage in the right cerebellopontine angle cistern and blood into the fourth ventricle from a ruptured peripheral aneurysm of the anterior inferior cerebellar artery (AICA) located at the meatal loop. Concomitantly, a contralateral peripheral aneurysm was found in the posterior inferior cerebellar artery (PICA). A second peripheral aneurysm, not identified by previous angiography, was found in the caudomedial branch of AICA. We describe this diagnostic dilemma, management, and review the clinical presentation and location of 84 other peripheral AICA aneurysms reported in the literature.     

Two cases of persistent trigeminal artery variant

Two cases of persistent trigeminal artery variant were found in 2000 cases who had examination of cerebral angiography in our hospital from 1975 to 1986. The first case was a 44-year-old female who admitted in our hospital for the examination of vertigo. Cerebral angiography demonstrated a superior cerebellar artery originating from the precavernous portion of the right internal carotid artery. The second case was a 67-year-old female who admitted in our hospital for the treatment of subarachnoid hemorrhage. Cerebral angiography demonstrated an anterior inferior cerebellar artery originating from the precavernous portion of the right internal carotid artery. In this case, a fusiform aneurysm was found in the origin of the persistent trigeminal artery variant. The ruptured aneurysm was thought to be a basilar artery aneurysm.     

Anterior inferior cerebellar artery aneurysm: report of 2 cases

Anterior inferior cerebellar artery aneurysm (AICAA) is not common. We have encountered only two cases of AICAA in our 205 cases of intracranial aneurysm. AICAAs were mostly located on the branches or loops of anterior inferior cerebellar artery at the pontine-cerebellar angle, and all of them were saccular. These neurological findings were mainly concerned with the syndrome of the pontine-cerebellar angle. It was found mainly due to subarachnoid hemorrhage. Angiography may establish the diagnosis. Surgical treatment is the first choice. The aneurysm was approached by suboccipital craniectomy and clipped. Postoperatively there were a great proportion of neurological deficits of auditory or/and facial nerves.     

An intracranial aneurysm on the feeding artery of a cerebellar hemangioblastoma. Case report.

A case of cerebellar hemangioblastoma with a coexistent arterial aneurysm on the feeding artery of the tumor is reported. The patient presented with an acute onset of headache, loss of consciousness, and left-sided hemiparesis due to a posterior fossa hemorrhage found adjacent to a hemangioblastoma. Four-vessel angiography revealed an aneurysm on the anterior inferior cerebellar artery (AICA), which was the main feeding vessel of the hemangioblastoma. Successful total excision of the hemangioblastoma and clipping of the AICA aneurysm achieved in a one-stage operation was demonstrated on postoperative angiography.     

Ruptured aneurysm of a posterior inferior cerebellar artery communicating artery. Case report and histological findings

A hypertensive 60-year-old man presented with a rare aneurysm arising from the posterior inferior cerebellar artery (PICA) communicating artery, manifesting as subarachnoid hemorrhage with intraventricular hemorrhage. Angiography showed a small aneurysm arising from a fine and tortuous artery interconnecting the bilateral vermian branches of distal PICAs. The right PICA was absent and its vermian territory was supplied by the left PICA through this communicating artery. The right anterior inferior cerebellar artery was also connected to the vermian branch of the right PICA. At surgery, a reddish and apparent fusiform aneurysm was noted at the top of the arterial loop under the cerebellar vermis. Microsurgical trapping and removal of the aneurysm was performed without complication. Histological examination demonstrated typical findings of a true aneurysm. Only four previous cases of aneurysm of the communicating artery between the bilateral distal PICAs have been reported. In all five reported cases including ours, the PICA communicating artery contributed to the collateral blood supply of the contralateral vermian territory based on vascular anomalies. Hemodynamic stress and congenital vulnerability may have caused this aneurysm. Trapping is suitable to treat this precarious aneurysm if other collateral vessels supply the contralateral vermian territory.     

Cerebellar hemorrhage after coil embolization for a ruptured vertebral dissecting aneurysm

BACKGROUND: We present a case of ruptured vertebral dissecting aneurysm that exhibited cerebellar hemorrhage after successful embolization of the vertebral artery including the dissected site. CASE PRESENTATION: A 59-year-old man suffered a sudden onset of severe occipital headache when he looked up. Computed tomography demonstrated subarachnoid hemorrhage. Angiography revealed a right vertebral dissecting aneurysm distal to the posterior inferior cerebellar artery. Endovascular embolization of the aneurysm was performed with preservation of the posterior inferior cerebellar artery. The next day, the patient suffered a cerebellar hemorrhage in the vermis. The intracranial pressure was controlled by external ventricular drainage. The patient was discharged with mild cerebellar ataxia and bilateral abducens nerve palsy. CONCLUSION: In a case of vertebral dissecting aneurysm distal to the posterior inferior cerebellar artery, blood circulation in the vertebral arterial system may change after embolization of the aneurysm. In our case, the preserved posterior inferior cerebellar artery might have been hemodynamically stressed postoperatively, resulting in cerebellar hemorrhage. Therefore, strict control of blood pressure is essential in the acute stage after occlusion of the aneurysm.     

Familial cerebral aneurysms in three families, with two sibling pairs

The authors describe two pairs of siblings and a mother-son with cerebral aneurysms and the characteristics of familial intracranial aneurysms are briefly discussed. Family 1: A 54-year-old hypertensive woman (case 1) developed subarachnoid hemorrhage and a saccular aneurysm at the proximal portion of the left anterior cerebral artery was demonstrated on the angiogram. An azygos anterior cerebral artery was found as an associated anomaly. A 53-year-old hypertensive woman (case 2), a younger sister of case 1, suffered from subarachnoid hemorrhage and a saccular aneurysm at the distal portion of the right anterior cerebral artery was found on the angiogram. Vertebral angiogram showed bilateral fenestration of the extracranial vertebral arteries as a coincidental anomalies. Neck clipping for the aneurysms were successfully done in these two cases. Family 2: A 52-year-old hypertensive woman (case 3) suffered from subarachnoid hemorrhage and vertebral angiogram demonstrated a saccular aneurysm at the distal portion of the right posterior inferior cerebellar artery. The aneurysm was re-bled before surgical intervention and she died five days after admission. A 65-year-old hypertensive woman (case 4), an elder sister of case 3, was admitted with subarachnoid hemorrhage. Vertebral angiogram showed a saccular aneurysm on the proximal portion of the left posterior inferior cerebellar artery at the junction of the vertebral artery and a massive extravasation of the contrast medium from the aneurysm. The patient died three days after the onset before surgical intervention.(ABSTRACT TRUNCATED AT 250 WORDS)     

Occipital artery-anterior inferior cerebellar artery bypass with microsurgical trapping for exclusively intra-meatal anterior inferior cerebellar artery aneurysm manifesting as subarachnoid hemorrhage. Case report

A 77-year-old woman presented with an extremely rare exclusively intra-meatal anterior inferior cerebellar artery (AICA) aneurysm manifesting as subarachnoid hemorrhage. The aneurysm was located at a non-branching site of its meatal loop, deeply inside the internal auditory canal. The ipsilateral posterior inferior cerebellar artery was hypoplastic and the affected AICA supplied a wide vascular territory in the right cerebellum. The patient underwent microsurgical trapping of the distal AICA aneurysm in the acute stage. Collateral back flow to the parent artery was poor, so right occipital artery (OA)-AICA anastomosis was performed prior to aneurysm trapping. The postoperative course was uneventful, and magnetic resonance imaging after surgery did not demonstrate any ischemic change. Postoperative angiography showed complete disappearance of the AICA aneurysm and the apparently patent OA-AICA bypass. She did not suffer neurological deficit except for right incomplete hearing disturbance, and postoperative single photon emission computed tomography demonstrated absence of hemodynamic compromise in the cerebellum. OA-AICA anastomosis with aneurysm trapping could be the optimal surgical management of the AICA aneurysm located exclusively inside the internal auditory canal, especially if the parent artery supplies a wide vascular territory.