Distal Anterior Inferior Cerebellar Artery Research Articles

Surgical Clipping of a Ruptured Distal Anterior Inferior Cerebellar Artery Aneurysm: A Technical Note.

Aneurysms of the distal anterior inferior cerebellar artery (AICA) are uncommon. They can present with subarachnoid hemorrhage (SAH), cerebellopontine angle syndrome, or a combination of the two. We describe the technique and nuances of microsurgical clipping of a ruptured distal AICA aneurysm using a retrosigmoid approach.After performing the craniotomy, the AICA was exposed in a distal to proximal fashion and the aneurysm and the proximal parent vessel were identified. After establishing proximal control, a clip was placed across the neck of the aneurysm to obliterate it while maintaining flow within the parent vessel. Finally, the flow within the parent vessel was confirmed and the final clip position was checked to ensure that it was not compressing any of the cranial nerves in the vicinity. The aneurysm was completely obliterated, and the parent vessel remained patent.Distal AICA aneurysms are rare and challenging to treat. The retrosigmoid approach is commonly used to treat these aneurysms. Careful planning, which includes studying the vascular anatomy and the aneurysm characteristics, and proficient execution of the procedure can increase the safety and improve outcomes of surgical clipping of these aneurysms.

Microvascular Decompression of Facial Nerve and Pexy of the Left Vertebral Artery for Left Hemifacial Spasm: 3-Dimensional Operative Video.

A 73-yr-old man presented with intractable left hemifacial spasm of 4 yr duration. Brain magnetic resonance imaging showed significant compression of left facial nerve by the left vertebral artery (VA) and anterior inferior cerebellar artery (AICA).The patient underwent a left retrosigmoid craniotomy and a microvascular decompression of the cranial nerve (CN) VII. Intraoperatively, we found that the distal AICA had a protracted subarcuate extradural course.1 This was relieved by intra/extradural dissection. The left VA and the AICA loop were compressing the root exit zone of CN VII. The VA was mobilized, and pexy into the petrosal dura was done with 8-0 nylon sutures (Ethilon Nylon Suture, Ethicon Inc, a subsidiary of Johnson & Johnson, Somerville, New Jersey). Once this was done, the lateral spread disappeared.2 The AICA loop was decompressed with 2 pieces of Teflon felt (Bard PTFE felt, Bard peripheral Vascular Inc, a subsidiary of CR Bard Inc, Temp, Arizona). After this, wave V of the brainstem auditory evoked potential (BAEP) disappeared completely, with no recovery despite the application of the nicardipine on the internal auditory artery (IAA). The IAA appeared to be stretched by the microvascular decompression. Arachnoidal dissection was done to release the CN VIII and an additional felt piece was placed to elevate the AICA loop; the BAEP recovered completely. The patient had a complete disappearance of the hemifacial spasm postoperatively, and hearing was unchanged.This 3-D video shows the technical nuances of performing a vertebropexy, release of the AICA from its extradural subarcuate course, and the surgical maneuvers in the event of an unexpected change in neuromonitoring response. The suture technique of vertebropexy is preferred to a loop technique, to avoid kinking of the VA.3Informed consent was obtained from the patient prior to the surgery that included videotaping of the procedure and its distribution for educational purposes. All relevant patient identifiers have also been removed from the video and accompanying radiology slides.

Ruptured partially thrombosed anterior inferior cerebellar artery aneurysms: two case reports and review of literature.

ABSTRACTAneurysms arising from the distal anterior inferior cerebellar artery (AICA) are very rare. When the parent artery is an AICA−posterior inferior cerebellar artery (PICA) variant, occlusion of the artery, even distal to the meatal loop, leads to a significant area of cerebellar infarction. We report two cases of ruptured partially thrombosed distal AICA aneurysms. In both cases, the parent artery was an AICA−PICA variant. The aneurysms were clipped in one case and trapped following occipital artery (OA)−AICA anastomosis in another case. It is important to keep the OA as a donor artery for revascularization in the treatment of the AICA−PICA variant aneurysms, especially when the absence of intra-aneurysmal thrombus is not comfirmed preoperatively.

Clinical Features and Treatment of Distal Intracranial Aneurysms.

To analyze the clinical characteristics, therapies, and outcomes of distal intracranial aneurysms, the authors retrospectively studied the clinical and imaging data of 18 patients with distal intracranial aneurysms. There were 10 males and 8 females, aged from 11 months to 59 years (mean, 40.4 ± 11.4 years). All patients were diagnosed by digital subtract angiography. Aneurysm locations were as follows: distal anterior cerebral artery (n = 5), distal middle cerebral artery (n = 2), distal posterior cerebral artery (n = 6), distal posterior inferior cerebellar artery (n = 3), distal anterior inferior cerebellar artery (n = 1), and distal superior cerebellar artery (n = 1). Endovascular embolization was performed on 16 patients, including coil embolization on 10 patients and embolization using Glubran 2 surgical glue on 6 patients, and 7 of the 16 patients also underwent parent artery occlusion. Aneurysms were all completely embolized at the first phase for these 16 patients. The other 2 patients underwent craniotomy with hematoma evacuation and complete aneurysm clipping. Postoperatively, 14 patients showed a good recovery, 2 patients had neurological deficits, 1 patient had seizures and was managed with drugs, 1 patient developed hydrocephalus, and a ventriculo-peritoneal shunt was performed. Follow-up angiographies showed no aneurysm recurrence. Clinical manifestations of distal intracranial aneurysms are varied. Their treatment should follow the principle of individual choice. Endovascular embolization is an effective way to treat distal intracranial aneurysms; and for those with intracranial hematoma, craniotomy with hematoma evacuation and aneurysm clipping may be a feasible treatment.

Partially thrombosed giant aneurysm arising from a distal anterior inferior cerebellar artery–posterior inferior cerebellar artery variant: A case report

Abstract Anterior inferior cerebellar artery (AICA)–posterior inferior cerebellar artery (PICA) is a well-known variant in cerebral arteries. However, aneurysms located on the variant are rare and a giant one has not been reported. We report a case of a partially thrombosed giant aneurysm arising from an AICA–PICA variant. The patient was a 42-year-old man who presented with right hearing loss and facial numbness associated with left hemidysesthesia. Magnetic resonance imaging revealed an approximately 3.0-cm mass lesion at the right cerebello-pontine angle (CPA). Angiography showed a partially thrombosed aneurysm arising from the right AICA–PICA. The aneurysm was treated with endovascular trapping and surgical thrombectomy. Although cerebral aneurysm is known to occur at this site, this case provides awareness, that manifestations of aneurysms in the CPA include progressive multiple cranial nerve palsies and sensory disturbance caused by brainstem compression.

A case of ruptured intrameatal aneurysm successfully treated with coil embolization.

Aneurysms within the internal acoustic canal are rare. We report the case of a 71-year-old female with subarachnoid hemorrhage resulting from a ruptured distal anterior inferior cerebellar artery which was not detected on initial radiological examination. A second rupture was detected by contrast-enhanced computed tomography and successfully treated by endovascular coil embolization. The patient recovered without neurological deficits. To the best of our knowledge, this is the first report of an intrameatal aneurysm treated by endovascular coil embolization. We suggest endovascular coil embolization as an alternative to open surgery, even in cases of deep intrameatal aneurysm.

瘤内塞栓術を施行した内耳道内破裂 distal AICA 動脈瘤の1 例：症例報告と文献レビュー

瘤内塞栓術を施行した内耳道内破裂 distal AICA 動脈瘤の1 例：症例報告と文献レビュー

Endovascular treatment of distal intracranial aneurysms with Onyx 18/34

ObjectiveSurgical clipping and coil embolization of distally located intracranial aneurysms can be challenging. The goal of this study was to assess the feasibility, safety and efficacy of treatment of distal aneurysms with the liquid embolic agent Onyx 18/34. MethodsSixteen patients were treated with Onyx 18/34 for distally located aneurysms in our institution between March 2009 and September 2012. The technique consists of occluding the aneurysm as well as the parent vessel at the level of aneurysm with Onyx 18 or 34. Candidates for this treatment were patients with distal aneurysms including mycotic aneurysms, dissecting aneurysms, and pseudoaneurysms in which coiling was considered impossible. ResultsOf the 16 patients, 12 presented with subarachnoid and/or intracerebral hemorrhage. Median aneurysm size was 4.6mm. Aneurysm locations were as follows: Posterior inferior cerebellar artery (n=5), distal anterior inferior cerebellar artery (n=3), distal pericallosal (n=3), distal anterior cerebral artery (n=3), lenticulostriate artery (n=1), and anterior ethmoidal artery (n=1). There were 4 mycotic aneurysms. Complete aneurysm obliteration was achieved in all 6 patients with available angiographic follow-up. There was only 1 (6.3%) symptomatic complication in the series. There were no instances of reflux or accidental migration of embolic material. Favorable outcomes were noted in 82% of patients at discharge. Two patients with mycotic aneurysms died from cardiac complications of endocarditis. No aneurysm recanalization or rehemorrhage were seen. ConclusionParent vessel trapping with Onyx 18/34 offers a simple, safe, and effective means of achieving obliteration of distal challenging aneurysms.

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.

Ruptured Intrameatal Aneurysm of the Anterior Inferior Cerebellar Artery Accompanying an Arteriovenous Malformation: a Case Report

The distal anterior inferior cerebellar artery (AICA) aneurysms located inside the internal auditory canal are rare. The association of the distal AICA aneurysms and an arteriovenous malformation (AVM) on the same arterial trunk is exceptional. Eight reports of a total of ten cases have been published and all of the reported aneurysms were located in the meatal or postmeatal segment of the AICA. Herein, we report a case of ruptured aneurysm in the intrameatal portion of the AICA accompanying an AVM fed by the same artery. A 55-year-old man suffering from subarachnoid hemorrhage due to a ruptured intrameatal aneurysm with a small AVM underwent surgical trapping of the meatal loop, resulting in uneventful recovery. Follow-up angiography demonstrated neither aneurysm nor residual AVM nidus. We propose that trapping of the meatal loop could be a safe and feasible alternative to unroofing followed by neck clipping in selected patients with an intrameatal aneurysm of the AICA. We also review here the relevant literature.

Occipital Artery-Anterior Inferior Cerebellar Artery Bypass With Microsurgical Trapping for Exclusively Intra-meatal Anterior Inferior Cerebellar Artery Aneurysm Manifesting as Subarachnoid Hemorrhage

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.

Surgical Management of a Ruptured and Unruptured Distal Anterior Inferior Cerebellar Artery Aneurysm. Report of 2 Cases and Review of the Literature

Surgical Management of a Ruptured and Unruptured Distal Anterior Inferior Cerebellar Artery Aneurysm. Report of 2 Cases and Review of the Literature

Intrameatal aneurysm of the anterior inferior cerebellar artery

Aneurysms of the distal part of the anterior-inferior cerebellar artery (AICA) are rare, with an incidence of 0.1% to 0.5%. We report a 55-year-old woman suffering from a subarachnoid hemorrhage resulting from a ruptured intrameatal aneurysm of the AICA. A left retrosigmoid craniotomy was performed and the aneurysm was clipped without post-operative deficits. Follow-up angiography demonstrated exclusion of the aneurysm, confirming preservation of the distal AICA. We review the pertinent literature and discuss clinical presentation, radiological findings and surgical management of this patient.

Endovascular management of distal anterior inferior cerebellar artery aneurysms: Report of two cases and review of the literature

Background:Aneurysms of the anterior inferior cerebellar artery (AICA), especially those located in the distal portion of the AICA, are rare. There are few reported cases treated with surgery or endovascular embolization.Case Description:We report two cases of fusiform distal AICA aneurysms presenting with subarachnoid hemorrhage. Parent artery occlusion with coils and n-butyl cyanoacrilate (n-BCA) resulted in complete aneurysm occlusion and prevented rebleeding. Both patients presented postprocedure neurological deficits, but have made a good recovery at 4 and 10 months, respectively.Conclusion:Occlusion of the parent artery for the treatment of ruptured fusiform distal AICA aneurysms is effective but has significant neurological risks.

Embolization of a ruptured aneurysm of the distal anterior inferior cerebellar artery with parent artery preservation

Embolization of a ruptured aneurysm of the distal anterior inferior cerebellar artery with parent artery preservation

Endovascular Treatment for Ruptured Distal Anterior Inferior Cerebellar Artery Aneurysm -Case Report-

A 73-year-old woman presented with subarachnoid hemorrhage caused by a ruptured left distal anterior inferior cerebellar artery (AICA) aneurysm. Computed tomography showed a thin subarachnoid hemorrhage in the ambient cistern, and digital subtraction angiography revealed an aneurysm arising from the lateral branch of the left AICA, which was separate from the meatal loop. Endovascular treatment was performed to achieve parent artery occlusion using two Guglielmi detachable coils. Postoperatively, the patient had no complications except for left hearing disturbance, and she was independent in daily life. Endovascular parent artery occlusion for distal AICA aneurysm, especially distal from the meatal loop, can avoid sacrificing the internal auditory artery if the lateral branch of the AICA could be occluded more distally from the meatal loop. Sufficient collateral circulation prevents major infarction, and this strategy may be the first-line treatment choice.

Management of anterior inferior cerebellar artery aneurysms: an illustrative case and review of literature

Aneurysms of the anterior inferior cerebellar artery (AICA) are relatively rare among intracranial aneurysms. They can occur in 1 of 3 regions of the AICA: 1) craniocaudal (high or low riding), 2) mediolateral-premeatal (proximal), and 3) meatal-postmeatal (distal). The management strategies for treatment differ according to the location and configuration of the aneurysm. The existing body of neurosurgical literature contains articles published on aneurysms arising from the AICA near the basilar artery (BA), intracanalicular/meatal aneurysms, and distal AICA. Several therapeutic options exist, encompassing microsurgical and endovascular techniques. The authors describe a case of treatment involving a large BA-AICA aneurysm approached via exposure of the presigmoid dura using a retromastoid suboccipital craniectomy and partial petrosectomy. Treatment of these lesions requires detailed knowledge of the anatomy, and an anatomical overview of the AICA with its arterial loops and significant branches is presented, including a discussion of the internal auditory (labyrinthine) artery, recurrent perforating arteries, subarcuate artery, and cerebellosubarcuate artery. The authors discuss the various surgical approaches (retromastoid, far lateral, subtemporal, and transclival) with appropriate illustrations, citing the advantages and disadvantages in accessing these AICA lesions in relation to these approaches. The complications of these different surgical techniques and possible clinical effects of parent artery occlusion during AICA surgery are highlighted.

De novo intracranial aneurysm formation after Gamma Knife radiosurgery for vestibular schwannoma

Vascular complications, including vessel occlusion and hemorrhage, can arise after radiosurgery; however, hemorrhage due to a ruptured de novo aneurysm after Gamma Knife radiosurgery (GKS) for tumor is extremely rare. To the authors' knowledge, only a single case of de novo aneurysm formation after GKS for vestibular schwannoma has been previously reported. In this study, they describe their experience with the treatment of a 74-year-old woman with subarachnoid hemorrhage limited to the cerebellopontine cistern, who had undergone GKS for vestibular schwannoma 5 years earlier. Cerebral angiography demonstrated a left distal anterior inferior cerebellar artery aneurysm; coil embolization was attempted and failed. However, self-resolution of the aneurysm was revealed on follow-up angiography.

Ruptured pseudoaneurysm following Gamma Knife surgery for a vestibular schwannoma

A 75-year-old woman underwent Gamma Knife surgery (GKS) for a vestibular schwannoma. Eight years after GKS, she suffered sudden onset of headache. Computed tomography revealed diffuse subarachnoid hemorrhage around the cisterns of the posterior fossa. Right vertebral artery angiography showed an aneurysm arising from the lateral pontomedullary segment of the left anterior inferior cerebellar artery. The aneurysm was not located at a branching site. Trapping of the distal anterior inferior cerebellar artery aneurysm was performed, and the aneurysm was removed. The pathological features of this aneurysm are discussed. This aneurysm was diagnosed as a pseudoaneurysm pathologically. This is the first report of aneurysm formation with pathological findings following GKS for a vestibular schwannoma.

A distal AICA aneurysm

Aneurysms of the posterior fossa have been reported to account for 8 to 12% of all intracranial aneurysms1-3. Among these aneurysms, those of the distal AICA (anterior inferior cerebellar artery) are exceedingly rare, fewer than 100 cases have been reported, with a reported incidence of 0.1–0.5%4. Of the major arteries of the posterior fossa, the AICA is the least likely to harbor an aneurysm5. In Locksley’s review of the first cooperative aneurysm study6, only two cases of AICA aneurysms were [...]