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.     

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.     

Embolization for aneurismal dilatation associated with ruptured dissecting anterior inferior cerebellar artery aneurysm with preservation of the parent artery: case report

We report a rare case of a ruptured dissecting anterior inferior cerebellar artery (AICA) aneurysm treated by endosaccular embolization with a Guglielmi detachable coil (GDC). An 85-year-old female presented with headache. Computed tomographic (CT) scan showed subarachnoid hemorrhage and intraventricular hemorrhage in the fourth ventricule. Cerebral angiography and 3D-CT angiography revealed an aneurysmal dilatation at the anterior pontine segment of the right AICA with a diagnosis of arterial dissection. The right posterior inferior cerebellar artery (PICA) was absent and the right AICA supplied the territory normally nourished by the right PICA. The aneurismal dilatation was occluded by endosacullar embolization with preservation of the AICA. The distal AICA aneurysm is rare and only seven cases treated with endovascular embolization have been reported. In these, six cases were treated by parent artery occlusion with coil and the subsequent three cases presented with ischemic complications. Only one case was treated by endosaccular embolization with GDC. To our knowledge, this is the second report of the distal AICA aneurysm treated by endosaccular embolization with GDC. Distal AICA aneurysms are briefly discussed while reviewing the literature.     

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.     

Aneurysm of the anterior inferior cerebellar artery at the internal auditory meatus: report of two cases

Aneurysm of the vertebrobasilar system is not a rare lesion but constituting 5-10% of all intracranial aneurysms. Aneurysm at the peripheral part of the anterior inferior cerebellar artery (AICA), however, is rare and only 20 cases have been reported previously. In this report, two cases of aneurysm arising at the junction between the AICA and internal auditory artery and extending into the internal auditory meatus are reported. The first patient was a 51-year-old male who was admitted because of sudden onset of dizziness, rt. tinnitus and deafness. Left vertebral angiograms demonstrated an AVM in the rt. cerebellar hemisphere and two aneurysms on the feeding arteries, one on the superior cerebellar artery and the other on the meatal loop of the rt. AICA. Removal of the AVM and neck clipping of the aneurysms, which were found unruptured, were performed through the rt. suboccipital approach. The second patient was a 42-year-old female who was admitted because of sudden onset of severe headache and vomiting followed by rt. tinnitus, deafness and double vision. CT scan showed subarachnoid clot mainly located in the rt. cerebellopontine angle. Repeated vertebral angiograms revealed an aneurysm at the meatal loop of the rt. AICA. Complete neck clipping was carried out. The clinical features of the aneurysms of this location can be divided into three subgroups according to the characters of onset: sudden onset with subarachnoid hemorrhage, insidious onset of the VII th, VIII th, nerve palsies by the mass effect of the aneurysm, intermittent episodes of the VIII th nerve disfunction due to the insufficiency of the internal auditory artery.(ABSTRACT TRUNCATED AT 250 WORDS)     

Anterior inferior cerebellar artery aneurysm, carotid bifurcation aneurysm, and dural arteriovenous malformation of the tentorium in the same patient

An exceptional combination of intracranial vascular malformations is reported: distal anterior inferior cerebellar artery (AICA) aneurysm, carotid bifurcation aneurysm, and dural arteriovenous malformation (DAVM) of the tentorium. The AICA aneurysm was the source of recurrent subarachnoid and cerebellar hemorrhage, revealed only after repeated vertebral angiography. After external drainage of associated hydrocephalus, both aneurysms were successfully clipped and the dural malformation was subtotally embolized. The literature concerning AICA aneurysms, DAVMs, and combined intracranial vascular malformations is reviewed and discussed.     

Rerupture following endovascular treatment for dissecting aneurysm of distal anterior inferior cerebellar artery with parent artery preservation: retreatment by parent artery occlusion with Guglielmi detachable coils

Summary Distal anterior inferior cerebellar artery (AICA) aneurysms are rare and most cases have been treated surgically by clipping, wrapping or trapping. We recently treated this 20-year-old male patient by an endovascular technique. At first, he was treated by intra-aneurysmal embolisation with parent artery preservation. But he presented with rerupture 1 month after embolisation. Follow-up angiography revealed the regrowth of the aneurysm, which was considered as a dissecting aneurysm. We performed occlusion of the AICA just proximal to the aneurysm to prevent fatal rebleeding. He gradually improved and his level of consciousness fully recovered. At 2 year follow up, he had no neurological deficits. We suggest that embolisation of distal AICA aneurysm with parent artery occlusion may be safe and a simple method in the treatment of distal AICA aneurysms.     

Ruptured dissecting anterior inferior cerebellar artery aneurysm--case report

A 39-year-old woman presented with a rare dissecting aneurysm of the proximal anterior inferior cerebellar artery (AICA). She presented with sudden onset of headache and vomiting, and subsequently became comatose with acute respiratory distress syndrome. Computed tomography showed subarachnoid hemorrhage and ventricular dilation. Left vertebral angiography identified a fusiform aneurysm at the proximal portion of the left AICA. The patient underwent endovascular treatment using Guglielmi detachable coils. The aneurysm was completely embolized. Computed tomography detected no infarcted areas in the regions supplied by the AICA. She was discharged without neurological deficits.     

Anterior inferior cerebellar artery aneurysm with a sudden onset of caudal cranial nerve symptoms

A case of the anterior inferior cerebellar artery aneurysm with a sudden onset of caudal cranial nerve symptoms was reported. A 20-year-old female suffered from sudden onset of dysphagia and throat pain. Three days later, she was admitted to our hospital, suffering from sudden onset of headache, nausea, vomiting and consciousness disturbance. On admission, consciousness disturbance, bilateral abducent nerve palsy, and left caudal cranial nerve palsy was observed. CT scan revealed a subarachnoid hemorrhage in the basal cisterns with the densest area in the left ambient cistern. Left vertebral angiogram revealed an aneurysm at the left anterior inferior cerebellar artery (AICA). On the third day after admission, operation was performed. The aneurysm was found near the jugular foramen, surrounded by thick clots. The dome was attached to the caudal cranial nerves, and the neck was located at the bending portion of AICA without branches. Neck ligation and clipping was performed. On the fortieth day after the operation, the patient was discharged from our hospital without neurological deficits. To our knowledge, aneurysm at the AICA is rare and only 33 cases have been reported. However, a case with a sudden onset of caudal cranial nerve symptoms, before evident symptoms due to subarachnoid hemorrhage, has never been reported previously.     

Embolization of a ruptured aneurysm of the distal anterior inferior cerebellar artery: case report and review of the literature.

BACKGROUND: Aneurysms of the distal anterior inferior cerebellar artery (AICA) are rare and almost all of them have been treated surgically, by wrapping or trapping, in the previous literature. Most cases of aneurysms associated with the auditory artery resulted in a hearing disturbance from the surgical procedure, although aneurysms far from the auditory artery had no deficit from trapping. METHODS: An 81-year-old woman presented with a ruptured aneurysm of the distal AICA. We planned a delayed treatment with intravascular embolization because of her advanced age and poor clinical status. Embolization of the distal anterior inferior cerebellar artery using detachable coils remote from the auditory artery was successful. RESULTS: Magnetic resonance imaging after embolization demonstrated no remaining lesion. The patient has been through rehabilitation and has gradually improved. CONCLUSION: Intravascular treatment of distal AICA aneurysms remote from the auditory artery may be safer and simpler than surgical treatment.     

Four cases of direct surgery for anterior inferior cerebellar artery aneurysms

Anterior inferior cerebellar artery (AICA) aneurysms are very rare. We carried out four direct operations for AICA aneurysms including two distal AICA aneurysms using lateral suboccipital retrosigmoid approaches (LSRA). We successfully performed the clipping by LSRA. but hearing loss occurred except in one of our cases which involved a chronic term operation in in our cases, In a 72 years old female with a ruptured dissecting aneurysm of the AICA anterior pontine segment, we performed the OA-PICA anastomosis first because of its being an AICA-PICA type, and then we continued to carry out the trapping operation of dissecting artery on day 0. She left our hospital cheerfully but hearing loss persisted on the operated side. Four examples of the dissecting aneurysm of AICA anterior pontine segment have been reported, but only our case involved the trapping with revascularization in acute stage. At the moment, there is no clinical or useful classification for distal AICA aneurysm because it is extremely rare. We will now propose a new classification. This classification is divided into two groups, (1) P (pons) -group and (2) C (cerebellum) -group. The P-group consists of pA (AICA anterior pontine segment). pL (lateral branch on the pons to the meatal loop) and pM (medial branch on the pons). C-group consists of m-loop (meatal loop), cL (lateral branch post meatal loop) and cM (medial branch on the cerebellum). From results of case reports (75 distal AICA aneurysms), we found that pA: 5 (6.7%), pL: 2 (2.8%), pM: 0, m-loop: 54 (72%), cL: 8 (11%), cM: 6 (8.3%). The followings factors were also found. (1) Occlusion of the parent artery of P-group without revascularization of peripheral circulation may entail the risk of death. (2) On the other hand, as for the C-group, the parent artery was able to be occluded without severe consequences, but hearing loss and/or cerebellar infarction occurred. We believe that this classification is simple and very useful for therapeutic strategies in both direct surgery and intravascular treatments for distal AICA aneurysms.     

Anterior inferior cerebellar artery aneurysms: six cases and a review of the literature

Aneurysms of the anterior inferior cerebellar artery are rare. Six cases of anterior inferior cerebellar artery (AICA) aneurysms treated at one center are presented. The six cases of AICA aneurysms were surgically treated. The clinical features, surgical process, complications, and follow-up are demonstrated. Six patients with six AICA aneurysms were presented including one AVM accompanied aneurysm and one giant aneurysm. Five aneurysms had ruptured, one was unruptured. Five patients presented with subarachnoid hemorrhage (SAH) including two with intraventricular hemorrhaging and one with an intraparenchymal hematoma. One aneurysm was proximal, two were distal, and three were meatal. All cases were treated surgically. Retrosigmoid and far-lateral craniectomy were included. Navigation was accomplished through intraoperative ultrasound and fluorescent angiography. Resection of the aneurysm after clipping was significant. The most common postoperative deficit involved the cranial nerves in four patients. Follow-up was available for all patients for a mean of 68 months. SAH is the most common presentation. The relationship between the aneurysms and the meatus is an important factor for neurological dysfunction. 3D-CTA and MRA may be considered as diagnostic adjuncts. Several special surgical techniques used in our cases are worth noting. Endovascular therapy for AICA aneurysms is in the process of development and should be reserved for special cases.     

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.     

Distal anterior inferior cerebellar artery aneurysms. Report of four cases

Aneurysms of the distal anterior inferior cerebellar artery (AICA) are rare; fewer than 100 cases have been reported. The authors detail their experience with four cases and present endovascular as well as microsurgical management options. The medical records and neuroimaging studies obtained in four patients who were treated at a single institution were reviewed. Clinical presentations, neuroimaging and intraoperative findings, and clinical outcomes were analyzed. There were three men and one woman; their mean age was 43 years. Two patients presented with acute subarachnoid hemorrhage (SAH), and two presented with ataxia and vertigo (one with tinnitus, the other with hearing loss). Angiographic studies demonstrated aneurysms of the distal segment of the AICA. In one patient with von Hippel-Lindau syndrome and multiple cerebellar hemangioblastomas, a feeding artery aneurysm was found on a distal branch of the AICA. Three of the patients underwent successful surgical obliteration of their aneurysms, one by clipping, one by trapping, and one by resection along with the tumor. The fourth patient underwent coil embolization of the distal AICA and the aneurysm. All patients made an excellent neurological recovery. Patients with aneurysms in this location may present with typical features of an acute SAH or with symptoms referable to the cerebellopontine angle. Evaluation with computerized tomography, magnetic resonance (MR) imaging, MR angiography, and digital subtraction angiography should be performed. For lesions distal to branches coursing to the brainstem, trapping and aneurysm resection are viable options that do not require bypass. Endovascular obliteration is also a reasonable option, although the possibility of retrograde thrombosis of the AICA is a concern.     

A ruptured choroidal artery aneurysm of the anterior inferior cerebellar artery obliterated via the endovascular approach: case report

Intraventricular aneurysms associated with fourth ventricular hemorrhage are rare. A case of a ruptured aneurysm in a choroidal branch of the right anterior inferior cerebellar artery (AICA) is reported here. A 56-year-old man presented with sudden onset of vertigo and nausea. CT scan showed an intraventricular hemorrhage within the fourth ventricle. Cerebellar angiography showed an aneurysm at the choroidal artery branching from the right AICA. The patient rejected both general anesthesia and craniotomy, so endovascular embolization under local anesthesia was performed using Guglielmi detachable coils (GDCs) and a fibered platinum coil. The distal portion of the right AICA and the aneurysm were obliterated. His postoperative course was fairly satisfactory. He suffered from a minimal gait disturbance caused by truncal ataxia for several days after the operation. He was discharged from hospital without neurological deficit. There have been only a few articles about choroidal artery aneurysms. As treatment, direct surgery has been recommended in past cases, but endovascular embolization of the parent artery was successfully performed in this case. Not only direct surgery but also endovascular surgery may be regarded as the treatments of choice for intraventricular aneurysms, depending on the size of the parent artery.     

Aneurysm of the internal auditory artery: Our experience and review of the literature

Summary The aneurysms of the internal auditory artery (IAA) situated distal from anterior inferior cerebellar artery (AICA)-IAA junction, are extremely rare lesions. A case of distal aneurysm of IAA is presented causing subarachnoid haemorrhage (SAH) and complete ipsilateral deafness. After the neurosurgical treatment the hearing of the patient definitely improved. The literature of distal aneurysms of AICA is reviewed focusing on the clinical features of these malformations, causing cerebello-pontine angle (CPA) symptoms with or without SAH.     

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.     

Clinical presentation and treatment of distal anterior inferior cerebellar artery aneurysms

Aneurysms located at the distal portion of the anterior inferior cerebellar artery (AICA) are rare, and their clinical features are not fully understood. We report the clinical features and management of nine distal AICA aneurysms in nine patients treated during the past decade at Kagoshima University Hospital and affiliated hospitals. Our series includes seven women and two men. Of their nine aneurysms, eight were ruptured and one was unruptured; six were saccular and three were dissecting aneurysms. The most prevalent location was the meatal loop (n?=?5) followed by the postmeatal (n?=?3) and premeatal segment (n?=?1) of the AICA, suggesting hemodynamic stress as an etiology of these distal AICA aneurysms. Of the nine patients, five presented with angiographic features suggestive of increased hemodynamic stress to the AICA and the common trunk of the posterior inferior cerebellar artery, with vertebral artery stenosis, marked laterality, and a primitive hypoglossal artery. We addressed eight aneurysms (eight patients) surgically; one aneurysm in one patient disappeared in the course of 3?months without surgical treatment. Of the eight surgically treated aneurysms, seven were ruptured and one was unruptured, five were clipped via lateral suboccipital craniotomy, two were trapped via lateral suboccipital craniotomy, and one was embolized. Good outcomes were obtained in six of the eight patients who underwent operation (75?%). We consider increased hemodynamic stress attributable to anatomic variations in the AICA and related posterior circulation to be the predominant contributor to the development of distal AICA aneurysms. Direct clipping and trapping yielded favorable outcomes in our series.     

Distal Anterior Inferior Cerebellar Artery Aneurysm Masquerading as a Cerebellopontine Angle Tumor: Case Report and Review of Literature

We present the case of a distal anterior inferior cerebellar artery (AICA) aneurysm masquerading as a cerebellopontine angle tumor in a 60-year-old right-handed man with previously undiagnosed polyarteritis nodosa (PAN). The patient presented with a 2-month history of progressive right-sided hearing loss, intermittent severe headache, and sudden onset of complete facial paralysis 3 weeks before admission. Magnetic resonance imaging, including post-gadolinium images, showed a 1.2-cm heterogeneously enhancing mass that slightly enlarged the right internal auditory canal. A right suboccipital craniotomy was performed, and a partially thrombosed fusiform AICA aneurysm was discovered just anterior to the VII/VIII nerve complex. The aneurysm was trapped and opened, and a thrombectomy was performed. Postoperatively, the patient experienced abdominal pain; liver function tests were abnormal. Investigation revealed a small retroperitoneal hemorrhage and aneurysms of the celiac axis and gastroduodenal arteries. Further investigation revealed an increased erythrocyte sedimentation rate, and a diagnosis of PAN was made. PAN is a well-identified factor in the genesis of peripheral vascular aneurysms. Aneurysms involving the hepatic, renal, coronary, pancreatic, and tibial arteries have been described. PAN is an extremely rare cause of intracranial aneurysm. Patients who present with aneurysms in unusual locations (e.g., distal AICA) should be investigated for vasculopathy and collagen vascular disorders.     

Rare anatomical variations of persistent trigeminal artery in two patients with non-aneurysmal subarachnoid hemorrhage

Carotid-basilar anastomoses are remnants of the fetal circulation and although rare, they may become symptomatic and should be recognized during cerebral angiography. Two patients are described with non-aneurysmal subarachnoid hemorrhage and persistent trigeminal arteries (PTA) found on cerebral angiography. In the first patient, the PTA ended in the anterior inferior cerebellar artery (AICA) and posterior inferior cerebellar artery. The second patient had a PTA terminating in the AICA and superior cerebellar artery. These rare anatomical PTA variants should be recognized on cerebral angiography.