Fluorescein-Guided Surgery for Arteriovenous Malformation.

Microscopes with fluorescence modality for videoangiography (VAG) using indocyanine green or sodium fluorescein (FL) have been used in cerebrovascular surgeries as tools for brain blood flow assessment in vascular diseases, especially in brain aneurysms, extracranial-intracranial bypass, and arteriovenous malformations (AVMs). Indocyanine green-VAG is a well-documented tool frequently employed as an adjunct to microsurgery for AVM treatment. Nevertheless, it's worth noting that the use of FL-VAG has been significantly underrepresented in medical literature, with only a few studies addressing its application in this context.1,2 We report a case of a 33-year-old woman with a grade 1 frontal unruptured AVM, admitted because of recurrent headache. The AVM was exposed with a centered craniotomy (Video 1). Three FL injections were administered at different timing: 1) at the procedure's outset (before any dissection), 2) when the surgeon estimated most feeders had been disconnected, and 3) after the removal of the nidus. FL-VAG allowed visualization of the superficial AVM vessels and its draining veins. After identification and disconnection of feeding arteries, diminished blood flow was visualized and the AVM was completely removed, confirming no residual lesion by absence of FL on the surgical bed. Postoperative digital angiography showed complete removal of the AVM. FL-VAG represents a valuable adjunct in the AVM resection by facilitating the assessment of blood flow within cerebral vessels. This can be helpful to modify surgical strategies in some circumstances (e.g., selection of the main feeders vs. arteries in passage) and to save time making decisions about draining vein division and nidus removal.

Intrauterine Correction of Fetal Myelomeningocele Through Minihysterotomy.

Spina bifida is the most common congenital central nervous system anomaly, resulting in lifelong neurologic, urinary, motor, and bowel disability.1 Its most frequent form is myelomeningocele, characterized by spinal cord extrusion into a sac filled with cerebrospinal fluid.1 We report the case of a 28-year-old pregnant female with no comorbidities. At 16 weeks of pregnancy, fetal ultrasound presented ventriculomegaly, cerebellar herniation, and lumbar myelomeningocele. At 22 weeks, intrauterine surgical correction was performed (Video 1). A minihysterotomy spanning approximately 3 cm was performed. The defect was opened, and the neural placode was dissected and released. This was followed by the isolation of the peripheric dura, which was molded into a tube and closed with watertight suture. Finally, the minihysterotomy was sutured and the skin was closed. The pregnancy followed its course with no complications, and the child was born at term with the lesion closed and no necessity of intensive care. Recent studies have demonstrated that infants who undergo open in utero myelomeningocele repair have better neurologic outcomes than those who are treated after birth.1,2 However, maternal morbidity is nonnegligible with the classical open surgery.2 Peralta et al2 propose a modification of the classic 6.0- to 8.0-cm hysterotomy in which the same multilayer correction of the spinal defect is performed through a 2.5- to 3.5-cm hysterotomy. This modification, called minihysterotomy, has been successfully performed outside of its creation center and was associated with reduced risks of preterm delivery and maternal, fetal, and neonatal complications.2,3.

Fluorescein-Guided Surgery for Malignant Gliomas.

Fluorescein (FS) was first used to visualize malignant brain tumors in 1948. FS accumulates in malignant gliomas where the blood-brain barrier is disrupted and provides intraoperative visualization that is similar to preoperative contrast-enhanced T1 images in which gadolinium accumulation is seen.1 FS can be viewed under white light, but the use of an operating microscope fitted with a dedicated filter (YELLOW 560 nm Filter, Carl Zeiss Meditec, Oberkochen, Germany) allows us to significantly reduce the dose needed to highlight tumoral tissue.1,2 FS is excited at 460-500 nm and emits a green, fluorescent emission wavelength at 540-690 nm.2 It is virtually free of side effects and has low costs3 (approximately 6.9 USD each vial: Brazil). Video 1 presents a case of a 63-year-old man who underwent a left temporal craniotomy to remove a temporal polar tumor. The FS is administered at the time of anesthesia before a craniotomy. The tumor was then removed with standard microneurosurgical technique by the alternating use of white light and YELLOW 560 nm filter illumination. The use of FS was found "helpful" to discriminate the brain tissue and tumor tissue (bright yellow). Fluorescein-guided technique with a dedicated filter on the surgical microscope is safe and allows complete resection of high-grade gliomas.

Risks for Oculomotor Nerve Palsy and Time to Recovery After Surgical Clipping of Posterior Communicating Artery Aneurysms: A Multicenter Retrospective Cohort Study.

BACKGROUND: Aneurysms of the posterior communicating segment of carotid artery (PcomA) have a high risk of rupture; when these nonruptured aneurysms are associated with oculomotor nerve palsy (ONP), the risk of rupture increases compared with asymptomatic nonruptured PcomA. OBJECTIVE: To retrospectively analyze the risk factors involved in ONP secondary to PcomA aneurysm and to study the factors involved in the recovery time of ONP once it is established. METHODS: This was a retrospective study of patients from 10 neurosurgery centers from October 2008 to December 2020. We analyzed age at diagnosis, presence of compressive neuropathy of the oculomotor nerve, presence of aneurysm rupture, largest aneurysm diameter, aneurysm projection, smoking, hypertension, diabetes, time between diagnosis and surgical treatment, as well as the outcome. RESULTS: Approximately 1 in 5 patients (119/511 23.3%) with a PcomA presented with ONP. We found that patients with aneurysms measuring greater than or equal to 7.5 mm were 1.6 times more likely to have ONP than those with aneurysms smaller than 7.5 mm. In our study, the prevalence of smoking in the PcomA + ONP group was 57.76%, and we also found that smokers were 2.51 times more likely to develop ONP. A total of 80.7% showed some degree of improvement, and 45.4% showed complete improvement with a median recovery time of 90 days. CONCLUSION: This study showed that 80.7% of patients with PcomA aneurysms undergoing surgical treatment with aneurysm clipping showed some degree of improvement of the ONP, with a median time to recovery between 90 and 120 days.

Surgical Resection of a Sylvian Arteriovenous Malformation.

Sylvian arteriovenous malformations (sAVMs) are rare and account for approximately 8%-11% of all intracranial arteriovenous malformations (AVMs).1 Because of their proximity to eloquent structures such as the motor speech center, insular cortex, and internal capsule, microsurgical resection of sAVMs remains a challenge. Several classifications have already been suggested for sAVMs, such as Sugita and Yasargil.1,2 It is well established that for low-grade AVMs, results of the microsurgical resection are excellent and tend to favor surgery,1-3 but in high-grade AVM, a multimodal assessment is necessary for formulating treatment strategies.1 In Video 1, we demonstrate the surgical resection of a ruptured sylvian temporal AVM. This AVM was localized in the superior surface of the temporal lobe, and its nidus was just beneath the cortical surface of this lobe. Because it was 5.1 cm at its largest diameter, had a deep drainage vein, and was localized adjacent to the Wernicke area, we classified it as a Spetzler-Martin grade IV AVM.4 Despite the high-grade AVM, microsurgical treatment was the choice in this ruptured AVM and there was no increase in morbidity.

Combined strategies on the treatment of cerebellar arteriovenous malformation.

Cerebellar arteriovenous malformations (AVMs) comprise 10%-15% of all intracranial AVMs and have a higher risk for morbidity and mortality than supratentorial AVMs. Patients with cerebellar AVMs present with hemorrhage more often than patients with cerebral AVMs, justifying an interventional treatment. Patient outcome can be predicted with specific grade systems, guiding vascular neurosurgeons in decision-making. The authors present the case of a 42-year-old man incidentally diagnosed with an unruptured cerebellar inferior vermian AVM, which was managed through a combined strategy of preoperative endovascular embolization of the main arterial feeders followed by microsurgical resection via midline suboccipital craniotomy, with a favorable outcome. The video can be found here: https://youtu.be/3WESejZbk90.

Impact of histological diagnosis on the treatment of atypical brainstem lesions.

For atypical brainstem lesions, histological diagnosis can have an impact on treatment, especially in cases where diffuse glioma is not found. Since radiotherapy is the only therapeutic modality that has shown clinical and radiographic improvement in patients with diffuse glioma, the misdiagnosis of diffuse glioma can have drastic consequences, particularly in patients with nontumorous lesions. Thus, the purpose of this study was to evaluate the impact of histological diagnosis on the treatment of atypical brainstem lesions. This was a retrospective study of 31 patients who underwent biopsy of atypical brainstem lesions. The procedures were performed between January 2008 and December 2018 at the Life Center Hospital and Santa Casa de Belo Horizonte, MG, Brazil. A diagnosis was obtained in 26 (83.9%) cases. Three patients presented complications: one presented bleeding with no clinical repercussions and two showed worsening of neurological deficit, only one of which was definitive. No mortality occurred due to the procedure. The histological diagnosis was diffuse glioma in seven cases (22.6%) and not diffuse glioma in 19 cases (61.3%). Thus, the histological diagnosis had an impact on the treatment of 19 patients (treatment impact rate: 61.3%). The histological diagnosis of intrinsic brainstem lesions is a safe, efficient procedure with a high diagnosis rate, and as such, it should be considered in the management of atypical lesions.

Evaluation of Accuracy and Reliability of a Smartphone Stereotactic Coordinates Checking Application.

BACKGROUND: Surgical assistance applications for smartphones have the potential to be used in daily practice; however, regular reviews of these tools are required. StereoCheck (Mevis, São Paulo, São Paulo, Brazil) is a mobile application (app) designed to compute stereotactic coordinates as a checking tool. The present study evaluated the accuracy and reliability of the StereoCheck app. METHODS: The present observational and prospective study included 26 patients who had undergone frame-based stereotactic brain biopsy. A standard stereotactic planning software (Framelink, version 5.0 [Medtronic, Minneapolis, Minnesota, USA]) was used to define the target coordinates. The surgical planning images were transferred to StereoCheck using 2 image input methods: photographs of the screen monitor and digitally exported images of the screen monitor. Five examiners performed the target coordinate definitions using StereoCheck on 2 occasions. The accuracy and reliability of the app were evaluated in tests that compared the planning methods (app vs. standard software), multiple examiners, and sequential tests. RESULTS: The StereoCheck accuracy using photographs of the screen was 2.71 ± 0.86 mm (95% confidence interval, 2.37-3.06). Using the digitally exported images, it was 0.82 ± 0.61 mm (95% confidence interval, 0.58-1.07). The accuracy between the 2 methods was greater using the exported images (P < 0.01) and was not affected by the clinical and radiological features. The accuracy of StereoCheck among multiple examiners and in sequential tests showed a mean distance between the targets and coordinates of <1.00 mm. Thus, an excellent level of reliability for the StereoCheck coordinates (intraclass correlation coefficient ≥0.8) was verified in all contexts. CONCLUSION: StereoCheck showed satisfactory accuracy and reliability. The use of photographs to compute the coordinates could lead to a significant decrease in the accuracy of the app.

Trends for in-hospital metrics in the treatment of intracranial aneurysms in Minas Gerais, Brazil.

Background: Aneurysmal subarachnoid hemorrhage (ASAH) and unruptured aneurysm (URA) are particularly important because of the high mortality rates, and physical and cognitive impairment, which affect the economically active population. The present work aims at describing the scenario regarding in-hospital indicators related to the following therapeutic approaches: vascular microsurgery (VMS) and endovascular therapy (EVT) in the state of Minas Gerais, Brazil, in order to gather information to construct hypotheses and plan actions. Methods: The study has an ecological design and it is also analytical for the time trends of 2008-2014. Trends for VMS and EVT therapies and mortality are estimated using linear regression, followed by the Prais-Winsten procedure. Data were obtained through Hospital Information System (Sistema de Informações Hospitalares - SIH) of Brazilian Public Health System (Sistema Único de Saúde - SUS). Results: In 2014, 601 procedures were performed, and out of these, 373 (62%) were triggered by SAH and 228 (38%) by URA. The frequency of procedures performed in males and in females results in a ratio of 1:2 for SAH procedures and 1:3 for URA procedures. A heterogeneous distribution of therapeutic approaches was seen among the hospital studied, suggesting a technological preference, which determines the therapeutic approach. Conclusion: Technological bias was observed for aneurysm treatment in Minas Gerais's hospitals. EVT is seen to have a growing trend to detriment of VMS (ß1 = 0.024; p = 0.025), with a stable mortality for both therapeutics in both pathologies (SAH and URA). EVT has been associated with a shorter hospital stay, with higher expenses for both ASAH and URA treatment. EVT showed an inverse correlation with in-hospital fatality for ASAH treatment.

Intraoperative Ultrasound Navigation with Doppler Function to Guide Arteriovenous Malformation Resection: 3-Dimensional Operative Video.

Intraoperative ultrasound navigation was initially introduced in the neurosurgical field for brain tumor surgery and was then extended to arteriovenous malformation surgery with good success. This tool provides real-time intraoperative images.1 Moreover, Doppler ultrasound permits early identification of feeding arteries and supplies the surgeon with a global impression of the flow dynamics.2 A further use of doppler is to check for residual nidus. Other advantages are the capacity to identify intracerebral hemorrhage.2 In this video, we demonstrate the case of a 15-yr-old patient who presented intracranial hemorrhage. Magnetic resonance imaging revealed the presence of left frontoparietal hematoma associated with an image suggestive of cerebral arteriovenous malformation (AVM). Arteriography confirmed the diagnosis of AVM fed by branches of the anterior cerebral and superficial drainage for the superior sagittal sinus. The patient was placed in dorsal decubitus with his head turned to the right and a left parietal-frontal craniotomy was performed. After the dura mater was opened, cortical mapping was performed to locate the motor and sensory cortex. After the mapping, ultrasound with doppler was performed to locate the AVM and the hematoma and determine its relation to the motor and sensory cortex. At the end of the surgery, doppler ultrasound was used again to ensure complete resection of the AVM. Intraoperative Ultrasound navigation with doppler is an inexpensive technology that can be used in the treatment of AVMs, especially in the subcortex, as it assists in locating the nidus and confirms its complete resection.

Safety and Efficacy of Surgical Treatment of Intracranial Aneurysms: The Experience of a Single Brazilian Center.

BACKGROUND: The use of microsurgery for aneurysm clipping has decreased considerably in recent years. This study was conducted to demonstrate the safety and effectiveness of surgical treatment of intracranial aneurysms even in less-developed countries. METHODS: This study was a retrospective review of the medical records of 320 patients with 416 aneurysms treated with microsurgical clipping at a single neurosurgical center in Brazil between 2008 and 2016. We evaluated postoperative outcomes using the modified Rankin Scale (mRS) at the time of hospital discharge, treatment efficacy by digital subtraction angiography (DSA) performed postoperatively, and mortality. RESULTS: The 320 patients with aneurysms included 228 patients with ruptured aneurysms and 92 with unruptured aneurysms. Overall, 81 (26.3%) had a poor outcome (mRS score >2), and the other 227 (73.4%) had a good outcome. The presence of a ruptured aneurysm was a statistically significant factor for poor outcome (P < 0.001) and mortality (P < 0.015). Giant and large aneurysms were also associated with poor outcome (P = 0.004). When analyzed separately, unruptured aneurysms with poor outcome were only associated with aneurysm size. Among the patients with ruptured aneurysms, those with Hunt and Hess (HH) grade >2 on hospital admission had unfavorable outcomes (P < 0.0001). Among the patients who underwent postoperative DSA, 207 (89.8%) had complete aneurysm occlusion and 24 (10.2%) had residual aneurysms, with reoperation required in 8 cases. CONCLUSIONS: Microsurgical treatment of intracranial aneurysms is an effective and safe method.

Levels of MMP-9 in patients with intracranial aneurysm: Relation with risk factors, size and clinical presentation.

BACKGROUND: Intracranial aneurysms are arterial anomalies affecting 2% to 3% of the general population in the world and these ruptures are associated with a high mortality. Some risk factors, such as age, gender, smoking, alcohol, hypertension and familial history are associated with the number of aneurysms and their size. In addition, inflammatory processes within the blood vessels of the brain can activate matrix metalloproteinase-9 (MMP-9), which degrades various components of the extracellular matrix, such as elastin. Thereby, this work has aimed at evaluating the relationship between plasma MMP-9 levels and the risk factors that are associated with intracranial aneurysm, as well as investigating the aneurysm statuses (ruptured and unruptured) and comparing them with the control volunteers. METHODS: Between August 2014 to June 2016, blood samples were collected from 282 patients (204 ruptured and 78 unruptured saccular intracranial aneurysms) and 286 control volunteers. The MMP-9 plasma levels were measured by ELISA. Statistical analyzes were performed with SPSS software when using parametric or nonparametric tests, after the normality tests. RESULTS: Higher levels of MMP-9 were found in the aneurysm groups as a whole and when they were stratified by rupture status, then compared with the control group (p < 0.0001). When stratifying them by diameter, those smaller than 7 mm presented high levels of MMP-9 (p < 0.0001), especially in the ruptured ones. As for risk factors, hypertension and smoking were the most important. However, hypertension was mostly associated with the ruptured aneurysms (p < 0.0001). CONCLUSIONS: High levels of MMP-9 were found in smaller ruptured and unruptured intracranial aneurysms (<7 mm) with strongest statistical associations than other sizes, especially when associated with smoking and hypertension.

Tenth case of bilateral hemifacial spasm treated by microvascular decompression: Review of the pathophysiology.

BACKGROUND: Bilateral hemifacial spasm (BHFS) is a rare neurological syndrome whose diagnosis depends on excluding other facial dyskinesias. We present a case of BHFS along with a literature review. METHODS: A 64-year-old white, hypertense male reported involuntary left hemiface contractions in 2001 (aged 50). In 2007, right hemifacial symptoms appeared, without spasm remission during sleep. Botulinum toxin type A application produced partial temporary improvement. Left microvascular decompression (MVD) was performed in August 2013, followed by right MVD in May 2014, with excellent results. Follow-up in March 2016 showed complete cessation of spasms without medication. RESULTS: The literature confirms nine BHFS cases bilaterally treated by MVD, a definitive surgical option with minimal complications. Regarding HFS pathophysiology, ectopic firing and ephaptic transmissions originate in the root exit zone (REZ) of the facial nerve, due to neurovascular compression (NVC), orthodromically stimulate facial muscles and antidromically stimulate the facial nerve nucleus; this hyperexcitation continuously stimulates the facial muscles. These activated muscles can trigger somatosensory afferent skin nerve impulses and neuromuscular spindles from the trigeminal nerve, which, after transiting the Gasser ganglion and trigeminal nucleus, reach the somatosensory medial posterior ventral nucleus of the contralateral thalamus as well as the somatosensory cortical area of the face. Once activated, this area can stimulate the motor and supplementary motor areas (extrapyramidal and basal ganglia system), activating the motoneurons of the facial nerve nucleus and peripherally stimulating the facial muscles. CONCLUSIONS: We believe that bilateral MVD is the best approach in cases of BHFS.

Angiographic and epidemiological characteristics associated with aneurysm remnants after microsurgical clipping.

BACKGROUND: Despite new techniques for the treatment of cerebral aneurysms, the percentage of aneurysm remnants after surgical intervention seems to be relatively constant. The objective of this study was to assess angiographic and epidemiological features associated with aneurysm remnants after microsurgical clipping. METHODS: This study was conducted from February 2009 to August 2012 on a series of 90 patients with 105 aneurysms referred to the Santa Casa of Belo Horizonte who were surgically treated and angiographically controlled. RESULTS: Surgical clipping was considered incomplete in 13.3% of the aneurysms. The mean age of cases with an aneurysm remnant was 57.5 years, whereas the mean age without aneurysm remnant was 49.7 years (P = 0.02). Aneurysm remnants were detected more frequently on the internal carotid artery, nevertheless, no statistically significant differences were verified when comparing the locations. Aneurysm size in the preoperative angiography verified that the mean size of aneurysms operated was 6.56 mm, such that in cases showing a postoperative remnant, the mean size was 9.7 mm and in cases with complete clipping it was 6.08 mm (P = 0.02). Postoperative angiography showed that, in cases with residual aneurysm, the number of clips used was higher - a mean of 1.8 for complete clipping and 3.1 for incomplete clipping (P < 0.001). CONCLUSIONS: Aneurysm size and patient age showed significant correlations with residual intracranial aneurysm. The mean number of clips used was higher in cases with incomplete occlusion.

Percutaneous Biopsy of Lesions in the Cavernous Sinus: A Systematic Review.

BACKGROUND: A wide variety of lesions may develop in the cavernous sinus region, including tumors or pseudotumors of inflammatory origin. Sometimes imaging is insufficient to ascertain a pathologic diagnosis. Percutaneous biopsy performed through the foramen ovale route may aid therapeutic decision making, avoiding unnecessary open surgery when lesions are confirmed to be nonsurgical or unresectable. We conducted a systematic review to determine the efficacy of percutaneous biopsy of cavernous sinus lesions. METHOD: A systematic search in PubMed, LILACS, Web of Science, and Scopus yielded 4495 potentially eligible abstracts. Fourteen studies describing 75 biopsy procedures for lesions in the cavernous sinus region were reviewed. The primary outcome measure was diagnostic success. Data were analyzed according to standard systemic review techniques. RESULTS: A diagnosis was obtained in 65 of the 75 cases described in the literature. Among all series, only 3 patients had permanent deficits. No individual studies reported mortality. The histopathologic evaluation revealed neoplastic diseases in 58 lesions. Meningiomas were found in 26 biopsy samples. Nonneoplastic diseases, originating from infectious, inflammatory, or deposition diseases, accounted for 6 biopsy samples. CONCLUSIONS: Percutaneous biopsy of cavernous sinus lesions is effective for diagnosis. Biopsy can be performed in patients with cavernous sinus masses, especially when neuroimaging fails to provide sufficient histopathologic data.

Long-Term Follow-Up of Anterior Pituitary Deficiency after Aneurysmal Subarachnoid Hemorrhage: Prospective Cohort.

OBJECTIVE: The aim of this study was to evaluate the prevalence of hypopituitarism in the acute stage after aneurysmal subarachnoid hemorrhage (SAH) as well at the chronic stage, at least 1 year after bleeding, to assess its implications and correlation with clinical features of the studied population. PATIENTS AND METHODS: This was a prospective cohort study that evaluated patients admitted between December 2009 and May 2011 with a diagnosis of SAH secondary to cerebral aneurysm rupture. Clinical and endocrine assessment was performed during the acute stage after hospital admission and before treatment at a mean of 7.5 days (SD ± 3.8) following SAH, and also at the follow-up visit at a mean of 25.5 months (range: 12-55 months) after the bleeding. RESULTS: Out of the 119 patients initially assessed, 92 were enrolled for acute stage, 82 underwent hormonal levels analysis, and 68 (82.9%) were followed up in both acute and chronic phases. The mean age and median age were lower among patients with dysfunction in the acute phase compared to those without dysfunction (P < .05). The prevalence of dysfunction in the acute phase was higher among patients with hydrocephalus on admission computed tomography (57.9%) than among those without it (P < .05). At chronic phase, there was an association between dysfunction and Hunt & Hess scale score greater than 2 (P < .05). CONCLUSIONS: We believe that there is not enough literature evidence to incorporate routine endocrinological evaluation for patient victims of SAH, but we should always keep this differential diagnosis in mind when conducting long-term assessments of this population.

Prevalence of Cognitive Impairments in Patients with Good Functional Outcome in Late Phase Subarachnoid Hemorrhage / Prevalência de alterações cognitivas em pacientes com bom desfecho funcional na fase tardia da hemorragia subaracnóidea

Prior studies have shown high prevalence of neuropsychological deficits after aneurysmal subarachnoid hemorrhage; however, few studies detect cognitive impairments in patients with good functional outcome, measured whith Rankin Modified Scale, in the late phase of subarachnoid hemorrhage. We confirmed a high prevalence of alterations in neuropsychological tests in 44 patients with Rankin Modified 2.We proposed the application of simple and fast tests that allowed us to detect impairments with precision similar to that of complex cognitive batteries used in previous studies. We also attempt to confirm statistical association between factors that could be related to poor cognitive outcome, like Hunt-Hess scale classification, bleeding intensity measured with Fisher scale, therapeutic type (microsurgery ou embolization), and aneurysm localization; however, there was no significance.

Estudos anteriores mostraram que a prevalência de déficits neuropsicológicos após hemorragia subaracnóide aneurismática é alto,mas poucos estudos detectaram alterações cognitiva sem pacientes com bom desfecho funcional,medido através da escada de Rankin Modificada, na fase tardia da hemorragia subaracnóide. O estudo confirmou em 44 pacientes com RankiN Modificado 2 a alta prevalência de alterações em testes neuropsicológicos. Propusemos a aplicação de testes simples e rápidos, capazes de detectar alterações, com precisão semelhante a baterias cognitivas complexas utilizadas em estudos anteriores.Nós também avaliamos a associação estatística entre alguns fatores como a escala de Hunt-Hess (HH), a intensidade do sangramento pela escala de Fisher, tipo de tratamento (microcirurgia ou embolização) e localização do aneurisma, ao pior desempenho cognitivo, no entanto não houve significância.