Role of temporary arterial occlusion in subarachnoid hemorrhage outcomes: a prospective cohort study

Purpose: Temporary arterial occlusion (TAO) is a widespread practice in the surgical treatment of intracranial aneurysms. This study aimed to investigate TAO's role during ruptured aneurysm clipping as an independent prognostic factor on short- and long-term outcomes. Methods: This prospective cohort included 180 patients with ruptured intracranial aneurysms and an indication of microsurgical treatment. Patients who died in the first 12 hours after admission were excluded. Results: TAO was associated with intraoperative rupture (IOR) (odds ratio ­ OR = 10.54; 95% confidence interval ­ 95%CI 4.72­23.55; p < 0.001) and surgical complications (OR = 2.14; 95%CI 1.11­4.07; p = 0.01). The group with TAO and IOR had no significant difference in clinical (p = 0.06) and surgical (p = 0.94) complications compared to the group that had TAO, but no IOR. Among the 111 patients followed six months after treatment, IOR, number of occlusions, and total time of occlusion were not associated with Glasgow Outcome Scale (GOS) in the follow-up (respectively, p = 0.18, p = 0.30, and p = 0.73). Among patients who underwent TAO, IOR was also not associated with GOS in the follow-up (p = 0.29). Conclusions: TAO was associated with IOR and surgical complications, being the latter independent of IOR occurrence. In long-term analysis, neither TAO nor IOR were associated with poor clinical outcomes.

Manifestações oftalmológicas em paciente com aneurisma gigante de carótida interna / Ophthalmological manifestation in patient with gigantic aneurysm of the internal carotid

RESUMO Os aneurismas intracranianos são dilatações em segmentos arteriais que irrigam o sistema nervoso central. Acometem 2% da população e as alterações oftalmológicas podem ser as primeiras manifestações do quadro. O objetivo deste relato foi descrever um caso de aneurisma de artéria carótida interna que cursou com restrição da movimentação ocular, alteração do reflexo fotomotor, ptose palpebral, dor facial e cervical. O diagnóstico foi confirmado pela identificação do aneurisma por meio do exame de angiografia cerebral. Foi realizado teste de oclusão por balão, cujo resultado positivo possibilitou a oclusão total da artéria carótida interna por meio de ligadura cirúrgica, procedimento este realizado com sucesso.

ABSTRACT Intracranial aneurysms are dilations in segments of the arteries that irrigate the central nervous system. They affect 2% of the population and the ophthalmologic disorders may be the first evidence in the clinical examination. The aim of the report is to describe a case of an internal carotid artery aneurysm that showed restrictions of ocular movements, change of pupillary light reflex, palpebral ptosis, facial, and cervical pain. This diagnosis was confirmed by the identification of the aneurysm through angiography. A balloon occlusion test was performed, and its positive result made a complete occlusion of the Internal Carotid Artery possible through surgery ligation, procedure that was successful.

Outcomes of patients experiencing cardiovascular adverse events within 1 year following craniotomy for intracranial aneurysm clipping: a retrospective cohort study / 南方医科大学学报

OBJECTIVE@#To investigate the impact of postoperative serious cardiovascular adverse events (CAE) on outcomes of patients undergoing craniotomy for intracranial aneurysm clipping.@*METHODS@#This retrospective cohort study was conducted among the patients undergoing craniotomy for intracranial aneurysm clipping during the period from December, 2016 to December, 2017, who were divided into CAE group and non-CAE group according to the occurrence of Clavien-Dindo grade ≥II CAEs after the surgery. The perioperative clinical characteristics of the patients, complications and neurological functions during hospitalization, and mortality and neurological functions at 1 year postoperatively were evaluated. The primary outcome was mortality within 1 year after the surgery. The secondary outcomes were Glasgow outcome scale (GOS) score at 1 year, lengths of postoperative hospital and intensive care unit (ICU) stay, and Glasgow coma scale (GCS) score at discharge.@*RESULTS@#A total of 361 patients were enrolled in the final analysis, including 20 (5.5%) patients in CAE group and 341 in the non-CAE group. No significant differences were found in the patients' demographic characteristics, clinical history, or other postoperative adverse events between the two groups. The 1-year mortality was significantly higher in CAE group than in the non-CAE group (20.0% vs 5.6%, P=0.01). Logistics regression analysis showed that when adjusted for age, gender, emergency hospitalization, subarachnoid hemorrhage, volume of bleeding, duration of operation, aneurysm location, and preoperative history of cardiovascular disease, postoperative CAEs of Clavien-Dindo grade≥II was independently correlated with 1-year mortality rate of the patients with an adjusted odds ratio of 3.670 (95% CI: 1.037-12.992, P=0.04). The patients with CEA also had a lower GOS score at 1 year after surgery than those without CEA (P=0.002). No significant differences were found in the occurrence of other adverse events, postoperative hospital stay, ICU stay, or GCS scores at discharge between the two groups (P > 0.05).@*CONCLUSION@#Postoperative CAEs may be a risk factor for increased 1-year mortality and disability in patients undergoing craniotomy for intracranial aneurysms.

Vein of Galen Aneurysmal Malformations in Pediatric Patients Submitted to Endovascular Treatment: Report of 3 Cases

Objective To report three cases of vein of Galen aneurysmalmalformation (VGAM) in pediatric patients treated at the hemodynamics lab of Hospital Santa Isabel (HSI) in Blumenau, state of Santa Catarina, Brazil, from 2006 to 2020. Clinical presentation, endovascular treatment, and postprocedure evolution to date are included. Case description Three children aged 5 to 12 months with cardiac, respiratory, or neurological damage in the neonatal stage, were referred to the neurosurgery service and diagnosed with VGAM. The three patients underwent endovascular embolization of themalformation, with different clinical evolution throughout outpatient follow-up. Conclusion Vein of Galen aneurysmal malformations are uncommon vascular abnormalities that, until the advent of endovascular embolization, were associated with high morbidity and mortality rates. Its prognosis is linked with initial clinic, early diagnosis, and timely surgical correction.

Minimally Invasive Mini-orbitozygomatic Approach for Clipping an Anterior Communicating Artery Aneurysm: Virtual Reality Surgical Planning

Virtual reality (VR) has increasingly been implemented in neurosurgical practice. A patient with an unruptured anterior communicating artery (AcoA) aneurysm was referred to our institution. Imaging data from computed tomography angiography (CTA) was used to create a patient specific 3D model of vascular and skull base anatomy, and then processed to a VR compatible environment. Minimally invasive approaches (mini-pterional, supraorbital and mini-orbitozygomatic) were simulated and assessed for adequate vascular exposure in VR. Using an eyebrow approach, aminiorbitozygomatic approach was performed, with clip exclusion of the aneurysm from the circulation. The step-by-step process of VR planning is outlined, and the advantages and disadvantages for the neurosurgeon of this technology are reviewed.

Pure arterial malformation with associated aneurysmal subarachnoid hemorrhage: Two case reports and literature review / 中南大学学报(医学版)

In recent years, in the absence of venous component, dilated, overlapping, and tortuous arteries forming a mass of arterial loops with a coil-like appearance have been defined as pure arterial malformation (PAM). It is extremely rare, and its etiology and treatment have not yet been fully elucidated. Here, we reported 2 cases of PAM with associated aneurysmal subarachnoid hemorrhage in this paper. Both patients had severe headache as the first symptom. Subarachnoid hemorrhage was found by CT and computed tomography angiography (CTA) and PAM with associated aneurysm was found by digital subtraction angiography (DSA). In view of the distribution of blood and the location of aneurysms, the aneurysm rupture was the most likely to be considered. Based on the involvement of the lesion in the distal blood supply, only the aneurysm was clamped during the operation. It used to be consider that PAM is safety, because of the presentation and natural history of previously reported cases. Through the cases we reported, we have doubted about "the benign natural history" and discussed its treatment. PAM can promote the formation of aneurysms and should be reviewed regularly. The surgical indications for PAM patients with aneurysm formation need to be further clarified. Management of PAM patients with ruptured aneurysm is the same as that of ruptured aneurysm. Whether there are indications needed to treat simple arterial malformations remains to be further elucidated with the multicenter, randomized controlled studies on this disease.

Fisher Grading Scale and Cognitive Deficits ­ Literature Review

Subarachnoid hemorrhage (SAH) accounts for 5 to 10% of all types of stroke, with rupture of brain aneurysms being related to deficits in memory, executive functions, and language. Changes in brain functions appear to be related to the presence of blood in the subarachnoid space, and the Fisher Scale (FS) correlates the amount of blood identified on computed tomography (CT). This paper presents a literature review of the association of FS with cognitive deficits secondary to aneurysmal subarachnoid hemorrhage (aSAH), using PubMed. The attempt to correlate the amount of blood identified in the CT with the development of cognitive alterations presents conflicting data. It was evidenced that some of the studies did not perform cognitive tests, or did not show differences between the scores of FS due to sample difficulty. The FS, even with its limitations and imperfections, seems to be a safe and easily reproducible way to predict neurological, cognitive or neuropsychological deficits, in view of its routine use when analyzing patients with aSAH.

Artéria trigeminal e aneurisma segmentar da artéria carótida associadas a hemorragia subaracnóide / Trigeminal artery and segmental aneurysm of the carotid artery associated with subarachnoid hemorrhage

A persistência e a falha da involução das comunicações embrionárias entre a circulação cerebral anterior e posterior contribuem para anomalias vasculares em adultos. Esta variação é comumente detectada de forma incidental, causando sintomas muito raramente. Sua proximidade com os nervos oculomotor, troclear e abducente podem levar a paresia muscular ocular. Em alguns casos pode causar tinnitus pulsátil e ao espasmo de hemiface. Muitos casos de artéria trigeminal foram relatados como associados a aneurismas intracranianos.

The persistence and failure of the involution of embryonic communications between the anterior and posterior cerebral circulation contribute to vascular anomalies in adults. This variation is commonly detected incidentally, rarely causing symptoms. Its proximity to the oculomotor, trochlear, and abducent nerves can lead to ocular muscle paresis. Sometimes it can cause pulsatile tinnitus and hemiface spasm. Many cases of trigeminal artery have been reported to be associated with intracranial aneurysms.

Microsurgery of Cerebral Aneurysm: Epidemiological Profile

Objectives Intracranial aneurysm consists of localized dilatation of the vascular wall. Its importance includes the fearsome event of rupture and subarachnoid hemorrhage, which presents high morbimortality rates. The present study aimed to analyze the profile and clinical outcome of patients submitted to the microsurgical approach of cerebral aneurysm in the city of Criciúma, state of Santa Catarina, Brazil, from 2015 to 2018. Methods A retrospective observational study was performed, with secondary data collection and a quantitative approach of 47 charts. Results A predominance of females (74.5%) and amean age of 53 years old (53.53 9.64) was observed. The middle cerebral artery was the most affected vessel (36.2%), with the highest percentage of aneurysms being between 2.1mmand 7.0mm(65.9%). Therewas a correlation between consciousness level and classification on the Hunt-Hess (HH) scale. Patients with GlasgowComa Scale (GCS)> 7 points had a better prognostic score in the HH scale, and those with GCS 7 points had a worse prognostic score in the HH scale. Conclusions The present study observed the presence of important risk factors for cerebral aneurysm formation, such as gender, age, smoking, and systemic arterial hypertension. The present study can measure a correlation of the level of consciousness with the HH classification.

Residual lesions in patients undergoing microsurgical clipping of cerebral aneurysms in a reference university hospital

OBJECTIVES: This study aimed to analyze the incidence and epidemiological, angiographic, and surgical aspects associated with incomplete clipping of brain aneurysms in a cohort of patients undergoing microsurgical treatment. METHODS: The medical record data of patients who underwent microsurgery for cerebral aneurysm treatment and postoperative digital subtraction angiography, treated at the same teaching hospital between 2014 and 2019, were retrospectively analyzed. The studied variables involved epidemiological and clinical data, as well as neurological status and findings on neuroimaging. The time elapsed between hemorrhage and microsurgical treatment, data on the neurosurgical procedure employed for aneurysm occlusion, and factors associated with the treated aneurysm, specifically location and size, were also evaluated. RESULTS: One hundred and seventeen patients were submitted to 139 neurosurgical procedures, in which 167 aneurysms were clipped. The overall rate of residual injury was 23%. Smoking (odds ratio [OR]: 3.38, 95% confidence interval [CI95%]: 1.372-8.300, p=0.008), lesion size >10 mm (OR: 5.136, CI95%: 2.240-11.779, p<0.001) and surgery duration >6 h (OR: 8.667, CI95%: 2.713-27.681, p<0.001) were found to significantly impact incomplete aneurysm occlusion in the univariate analyses. CONCLUSION: Incomplete microsurgical aneurysm occlusion is associated with aneurysm size, complexity, and current smoking status. Currently, there is no consensus on postoperative assessment of clipped aneurysms, hindering the correct assessment of treatment outcomes.

The Role of Neurophysiological Monitoring during Complex Aneurysm Surgery: Report of Two Cases and Review of the Literature

The surgical treatment of intracranial aneurysms is a routine operation in the neurosurgeon practice. Complex aneurysms are those with morphological irregularities, usually large or giant; thrombosed, partially thrombosed or calcified; with aberrant fundus/neck ratio and near eloquent neurological structures. These cases demand special skills by the surgical team. The present article is a report of two cases of complex aneurysms successfully treated, with a discussion on the role of neurophysiological monitoring. In these two cases of supra- and infratentorial complex giant aneurysms, intraoperative monitoring was extremely relevant. Thus, we believe that treating complex and giant aneurysms carries several pitfalls, and the use of multimodal intraoperative monitoring is mandatory to mitigate risks and deliver the best result to the patient.

A1­A2 Fenestration Tube Technique for Clipping a Ruptured Anterior Communicating Artery Aneurysm

A fenestration tube is a clipping reconstruction technique that allows the preservation of critical vessels in aneurysm surgery. A patient with a ruptured anterior communicating artery (ACoA) aneurysm with a posterior projection was admitted to our neurosurgery unit. A right dominant A1 with rotation of the A2 fork was observed on preoperative computed tomography angiography (CTA). During surgery, we observed that the recurrent artery of Heubner branched off the A2 just distal to the neck of the aneurysm. Successful clipping was achieved by building an "A1­A2 fenestration tube," with preservation of the recurrent artery and of the ACoA perforators. Surgical nuances and the advantages of fenestration tubes are discussed.

Intracranial aneurysm and arachnoid cyst: just a coincidence? A case report

ABSTRACT CONTEXT: Presence of an arachnoid cyst and a non-ruptured intracystic brain aneurysm is extremely rare. The aim of this paper was to describe a case of a patient with an arachnoid cyst and a non-ruptured aneurysm inside it. Clinical, surgical and radiological data were analyzed and the literature was reviewed. CASE REPORT: A patient complained of chronic headache. She was diagnosed as having a temporal arachnoid cyst and a non-ruptured middle cerebral artery aneurysm inside it. Surgery was performed to clip the aneurysm and fenestrate the cyst. CONCLUSIONS: This report raises awareness about the importance of intracranial vascular investigation in patients with arachnoid cysts and brain hemorrhage.

Microsurgical Treatment of Posterior Cerebral Artery Aneurysm (P2P Segment): Case Report and Review of the Literature

Introduction Aneurysms of the posterior cerebral artery (PCA) represent 1% of all intracranial aneurysms and usually present with subarachnoid hemorrhage. Objective The aimof the present study is to describe the case of an adult man presenting a saccular aneurysm of the right PCA at the posterior half of the postcommunicating (P2P) segment, and to discuss the technical nuances of the approach and of the clipping process. Case Report An investigation of a chronic headache in a 55-year-old man found a saccular aneurysm located just posterior to the most lateral portion of the right cerebral peduncle. A digital subtraction arteriography revealed a 7.8 mm 5.6 mm 4.8 mm posterior-medial projecting aneurysm of the right PCA at the P2P segment. A subtemporal approach was performed with partial aspiration of the right parahippocampal gyrus for a better exposure of the vascular structures. A proximal temporary occlusion of the PCA was performed at the anterior half of the postcommunicating P2A segment. The aneurysm was clipped with two semi-curved clips. The patient presented an uneventful recovery and was discharged from the hospital on the third postoperative day without any additional neurological deficits. Conclusion Aneurysms of the PCA are an uncommon vascular disease that challenges the ability of the neurosurgeons due to their many anatomical nuances, to their vast number of perforators, and to the risk of bleeding. However, the operative management of aneurysms of the PCA is technically feasible, safe and effective when performed respecting microsurgical principles.

Ensayo pictórico: control imagenológico de aneurismas tratados ¿qué examen elegir? / Pictorial essay: imaging control of treated aneurysms. which exam to choose?

Resumen: El tratamiento de aneurismas intracraneanos rotos y no rotos incluye opciones quirúrgicas (clips vasculares) y endovasculares. Existen varios dispositivos y técnicas de manejo endovascular (coils, stents, diversores de flujo), cuyo conocimiento permite elegir e interpretar adecuadamente las técnicas de imágenes para el seguimiento no invasivo. Mediante una revisión pictográfica del control de aneurismas intracraneanos tratados quirúrgicamente y vía endovascular, se muestran las diferencias en la capacidad de caracterización en el seguimiento con angio TC, angio RM sin contraste (con técnica de "tiempo de vuelo" o "TOF" por sus siglas en inglés), angio RM con gadolinio endovenoso (C+) y angiografía por sustracción digital (ASD). Adicionalmente se entregan recomendaciones para el seguimiento de aneurismas según modalidad y dispositivo de tratamiento.

Abstract: Treatment of intracranial ruptured and unruptured aneurysms can be performed with surgical (vascular clips) or endovascular procedures (coils, stents, flw diverters). There are several devices and techniques for endovascular treatment. Knowledge of this techniques allows physicians to choose and interpret accurately imaging modalities for non-invasive follow-up. Through a pictorial essay of imaging follow-up of treated intracranial aneurysms we show the differences in characterization with computed tomography angiography, magnetic resonance angiography without contrast (time of flght or "TOF" technique), contrast enhanced MR angiography (C+) and digital subtraction angiography (DSA). Additionally we recommend imaging modalities for each treatment device.

Surgery of a Posterior Communicating Artery Aneurysm with Fetal-Type Circulation

Inadvertent occlusion of a fetal-type posterior communicating artery in aneurysm surgery could result in posterior circulation infarction and neurological morbidity. The case of a patient with an unruptured posterior communicating artery aneurysm with lateral projection and a fetal-type posterior communicating artery is presented. The utility of the carotid-oculomotor window as a surgical corridor to safely find the fetaltype posterior communicating artery is discussed.

A oclusão da artéria comunicante posterior do tipo fetal em cirurgia de aneurisma pode resultar em infarto da circulação posterior e morbidade neurológica. Apresentamos o caso de um paciente com aneurisma não roto da artéria comunicante posterior com projeção lateral e uma artéria comunicante posterior do tipo fetal. Discutimos a utilidade da janela carótida-oculomotora como um corredor cirúrgico para encontrar com segurança a artéria comunicante posterior do tipo fetal.

Rescue therapy with stent retrievers for thromboembolism during endovascular treatment of intracranial aneurysms / Terapia de resgate com stent para tromboembolismo durante tratamento endovascular de aneurismas intracranianos

ABSTRACT Thromboembolism is the most frequent complication in endovascular treatment of intracranial aneurysms, causing disability and death. As stent retrievers have achieved high rates of arterial recanalization in the management of ischemic stroke, these devices were tested as rescue therapy of thromboembolism during aneurysm embolization. We retrospectively analyzed 10 consecutive patients with transprocedural arterial occlusion, treated with mechanical thrombectomy at a single center. Good angiographic recanalization was achieved in eight cases, mTICI 3, 2b and 2a in five, three and two patients, respectively, without additional complications or any deaths. Five patients showed complete recovery (mRS 0) and all patients showed improvement of disability (average mRS 1.1) over a mean follow-up period of 31 months. Eight patients had good clinical recovery, while two remained with deficits (mRS 3 and 4). The study found that the stent retriever is a valuable, rapid and effective tool for restoring blood flow, improving the safety of endovascular treatment.

RESUMO Tromboembolismo é a complicação mais frequente no tratamento endovascular de aneurismas cerebrais, podendo causar morte ou sequelas. Como os stent retrievers alcançaram altas taxas de recanalização arterial no tratamento do acidente vascular encefálico isquêmico, testamos esses dispositivos para tratar eventos tromboembólicos ocorridos durante a embolização de aneurismas. Foram analisados retrospectivamente 10 pacientes apresentando oclusão arterial transoperatória, tratados com trombectomia mecânica em um único centro. Obtivemos recanalização angiográfica em oito casos, mTICI 3, 2b e 2a em cinco, três e dois pacientes, respectivamente, sem complicações adicionais ou óbito. Cinco casos apresentaram recuperação completa (mRS 0) e todos os pacientes apresentaram melhora dos déficits (mRS médio 1.1) durante acompanhamento médio de 31 meses. Oito pacientes apresentaram boa recuperação clínica, enquanto dois permaneceram com déficits (mRS 3 e 4). O estudo concluiu que stents são uma ferramenta valiosa, rápida e eficaz para restaurar o fluxo sanguíneo, aumentando a segurança do tratamento endovascular.

Progressive hematoma in anterior neck after endovascular treatment of middle cerebral artery aneurysm / Hematoma progressivo na região anterior do pescoço após tratamento endovascular de aneurisma da artéria cerebral média

Abstract Background: Cervical hematomas can lead to airway compromise, a life threatening condition, regardless of the cause. The following case is the first presentation of cervical hematoma as a complication of endovascular treatment of middle cerebral artery aneurysm. Case report: A 49 year-old woman was scheduled for stent placement under general anesthesia for middle cerebral artery aneurysm. Few days before intervention, acetyl salicylic acid and clopidogrel treatment was started. Following standard monitoring and anesthesia induction, the patient's trachea was intubated with a 7.5 mm endotracheal tube and the procedure was completed without any complications. Three hours later, dyspnea developed and physical examination revealed progressive swelling and stiffness in the neck. Endotracheal intubation was performed with a 6 mm diameter uncuffed tube with the aid of sedation. The vocal cords were completely closed due to compression. There was no leak around the endotracheal tube. The rapidly performed computerized tomography scans showed an enormous hematoma around the neck and extravasation of contrast medium through superior thyroid artery. After coil embolization of superior thyroid artery, she was taken to the intensive care unit as intubated and sedated. Surgical exploration of the hematoma was not recommended by the surgeons, because she was on clopidogrel. After two days, the patient's trachea was extubated safely ensuring that the swelling was sufficiently ceased and leak detected around the endotracheal tube. Conclusions: Securing the airway rapidly by endotracheal intubation is the most crucial point in the management of cervical hematomas. Diagnostic and therapeutic procedures should be performed only afterwards.

Resumo Justificativa: Hematomas cervicais podem levar ao comprometimento das vias aéreas, uma condição de risco para a vida, independentemente da causa. O presente caso é a primeira apresentação de hematoma cervical como uma complicação do tratamento endovascular de aneurisma da artéria cerebral média. Relato de caso: Uma mulher de 49 anos foi agendada para a colocação do stent sob anestesia geral para aneurisma da artéria cerebral média. Poucos dias antes da intervenção, um tratamento com ácido acetilsalicílico e clopidogrel foi iniciado. Após a indução da anestesia e o monitoramento padrão, a traqueia da paciente foi intubada com um tubo endotraqueal de 7,5 mm e o procedimento foi concluído sem quaisquer complicações. Três horas mais tarde, a paciente desenvolveu dispneia e o exame físico revelou edema progressivo e rigidez do pescoço. A intubação endotraqueal foi feita com um tubo de calibre 6 mm sem balonete com o auxílio de sedação. As pregas vocais estavam completamente fechadas devido à compressão. Não houve vazamento ao redor do tubo endotraqueal. Tomografias computadorizadas feitas rapidamente mostraram um enorme hematoma no pescoço e extravasamento do meio de contraste através da artéria tireoidiana superior (ATS). Após embolização com molas da ATS, a paciente foi levada para a unidade de terapia intensiva intubada e sedada. A exploração cirúrgica do hematoma não foi recomendada pelos cirurgiões porque a paciente tomava clopidogrel. Depois de dois dias, a traqueia da paciente foi extubada com segurança. Isso garantiu que o edema havia cessado o suficiente e o vazamento detectado ao redor do tubo endotraqueal também. Conclusões: Proteger as vias aéreas rapidamente por meio de intubação endotraqueal é a conduta mais crucial no manejo de hematomas cervicais. Os procedimentos diagnósticos e terapêuticos devem ser feitos somente após essa conduta.

Surgical Treatment of Posterior Circulation Aneurysms ­ Anatomical Study and Surgical Technique

Posterior circulation aneurysms represent 10­15% of intracranial aneurysms. The diagnosis is usually secondary to subarachnoid hemorrhage due to its initial asymptomatic presentation and higher risk of rupture compared with aneurysms in the anterior circulation. The surgical treatment of posterior circulation aneurysms is complex and challenging for neurosurgeons because of the particular anatomy of the posterior circulation with its close relation to the brainstem and cranial nerves and also because of the depth and narrowness of the surgical approach. Aneurysms from different locations have specific anatomical relationships and surgical approaches for better visualization and dissection. Therefore, a detailed anatomy knowledge of the posterior circulation is mandatory for an individualized preoperative planning and good neurological and angiographic outcomes.We selected the main aneurysm sites on the posterior circulation, such as: posterior inferior cerebellar artery, basilar trunk, basilar bifurcation, posterior cerebral artery (PCA) and superior cerebellar artery for a detailed description of the relevant anatomy related to aneurysm, and the main surgical approaches for its surgical treatment. Furthermore, we performed a literature review with the most recent outcomes regarding to the surgical treatment of posterior circulation aneurysms.

Aneurismas de circulação posterior representam de 10­15% dos aneurismas intracranianos. O diagnóstico, frequentemente, é secundário a hemorragia subaracnoide devido à apresentação assintomática na maioria dos casos e ao alto risco de sangramento comparado com aneurismas da circulação anterior. O tratamento cirúrgico de aneurismas de circulação posterior é complexo e desafiador para os neurocirurgiões devido à anatomia particular da região, profundidade do acesso cirúrgico, e relação intima com o tronco encefálico e os nervos cranianos. Aneurismas de diferentes localizações têm diferentes relações anatômicas e, portanto, acessos cirúrgicos específicos para melhor dissecção e visibilização de estruturas. Logo, um conhecimento detalhado de anatomia é mandatório para planejamento operatório individualizado e bons resultados clinico-radiológicos. Foram selecionadas as principais localizações de aneurismas de circulação posterior: Artéria cerebelar póstero-inferior; tronco de artéria basilar, bifurcação de artéria basilar, artéria cerebral posterior, e artéria cerebelar superior para detalhamento anatômico da anatomia relevante. O estudo objetiva realizar uma revisão da literatura dos principais resultados sobre tratamento cirúrgico de aneurismas de circulação posterior, além de descrever os principais pontos anatômicos relevantes à técnica microcirúrgica.