Geometry and Symmetry of Willis' Circle and Middle Cerebral Artery Aneurysms Development.

Background: A relationship between the geometry and symmetry of Willis' circle and intracranial aneurysms was reported for anterior communicating and posterior communicating (PCom) aneurysms. A similar association with the middle cerebral artery (MCA) aneurysms instead appeared weaker. Methods: We reviewed 432 patients from six Italian centers with unilateral MCA aneurysms, analyzing the relationship between the caliber and symmetry of Willis' circle and the presence of ruptured and unruptured presentation. CT-angiograms were evaluated to assess Willis' circle geometrical characteristics and the MCA aneurysm side, dimension and rupture status. Results: The hypoplasia of the first segment of the anterior cerebral artery (A1) was in approximately one-quarter of patients and PCom hypoplasia was in almost 40%. About 9% had a fetal PCom ipsilaterally to the aneurysm. By comparing the aneurysmal and healthy sides, only the PCom hypoplasia appeared significantly higher in the affected side. Finally, the caliber of the internal carotid artery (ICA) and the first segment of MCA (M1) caliber were significantly greater in patients with unruptured aneurysms, and PCom hypoplasia appeared related to the incidence of an ipsilateral MCA aneurysm and its risk of rupture. Conclusions: Although according to these findings asymmetries of Willis' circle are shown to be a risk factor for MCA aneurysm formation and rupture, the indifferent association with ipsilateral or contralateral hypoplasia remains a datum of difficult hemodynamic interpretation, thereby raising the concern that this association may be more casual than causal.

Differences and Correlations of Morphological and Hemodynamic Parameters between Anterior Circulation Bifurcation and Side-wall Aneurysms.

OBJECTIVE: The objective of this research was to explore the difference and correlation of the morphological and hemodynamic features between sidewall and bifurcation aneurysms in anterior circulation arteries, utilizing computational fluid dynamics as a tool for analysis. METHODS: In line with the designated inclusion criteria, this study covered 160 aneurysms identified in 131 patients who received treatment at Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, China, from January 2021 to September 2022. Utilizing follow-up digital subtraction angiography (DSA) data, these cases were classified into two distinct groups: the sidewall aneurysm group and the bifurcation aneurysm group. Morphological and hemodynamic parameters in the immediate preoperative period were meticulously calculated and examined in both groups using a three-dimensional DSA reconstruction model. RESULTS: No significant differences were found in the morphological or hemodynamic parameters of bifurcation aneurysms at varied locations within the anterior circulation. However, pronounced differences were identified between sidewall and bifurcation aneurysms in terms of morphological parameters such as the diameter of the parent vessel (Dvessel), inflow angle (θF), and size ratio (SR), as well as the hemodynamic parameter of inflow concentration index (ICI) (P<0.001). Notably, only the SR exhibited a significant correlation with multiple hemodynamic parameters (P<0.001), while the ICI was closely related to several morphological parameters (R>0.5, P<0.001). CONCLUSIONS: The significant differences in certain morphological and hemodynamic parameters between sidewall and bifurcation aneurysms emphasize the importance to contemplate variances in threshold values for these parameters when evaluating the risk of rupture in anterior circulation aneurysms. Whether it is a bifurcation or sidewall aneurysm, these disparities should be considered. The morphological parameter SR has the potential to be a valuable clinical tool for promptly distinguishing the distinct rupture risks associated with sidewall and bifurcation aneurysms.

Thromboembolic complications during and after embolization of unruptured aneurysms: A chronological outcome in periprocedural thromboembolic events.

Background: Ischemic complications develop after elective coil embolization procedures at a certain rate. The prevention of these events has been a longstanding issue for many interventional neuroradiologists. This study aimed to clarify whether procedural ischemic events after unruptured aneurysm embolization decrease over time with perioperative anti-thromboembolic treatment or surgical experience. Methods: This study included patients with cerebral aneurysms in our institution between July 2012 and June 2020. Dual-antiplatelet therapy (DAPT) was performed (Phase 1). Thromboembolic events developed at a certain rate; thus, rivaroxaban was administered with single-antiplatelet therapy (SAPT) to improve thromboembolic results (Phase 2), showing better outcomes than in Phase 1. Subsequently, DAPT was administered again (Phase 3). Ischemic complications were evaluated in each phase or compared between the DAPT group and the direct oral anticoagulant (DOAC) with the clopidogrel (DOAC+SAPT) group. Results: Relatively, fewer symptomatic ischemic events were noted in Phase 2 or the DOAC+SAPT group, but the outcome was not better in Phase 3 than in Phase 2. Symptomatic complications were more common in Phase 3 than in Phases 1 and 2. Conclusion: Ischemic complications occurred at a certain rate after endovascular procedures for unruptured aneurysms. The incidence did not decrease over time; particularly, standard DAPT plus postoperative anti-thromboembolic medication did not adequately decrease complications in Phase 3 compared to Phases 1 and 2. Therefore, accumulated experience or a learning curve could not explain the results. DOAC administration might decrease the risk of these events, but further accumulation of evidence or prospective investigation is warranted.

Trends in the Age of Patients Treated for Unruptured Intracranial Aneurysms from 1990 to 2020.

BACKGROUND: The decision for treatment for unruptured intracranial aneurysms (UIAs) is often difficult. Innovation in endovascular devices have improved the benefit-to-risk profile especially for elderly patients; however, the treatment guidelines from the past decade often recommend conservative management. It is unknown how these changes have affected the overall age of the patients selected for treatment. Herein, we aimed to study potential changes in the average age of the patients that are being treated over time. METHODS: A systematic search of the literature was performed to identify all studies describing the age of the UIAs that were treated by any modality. Scatter diagrams with trend lines were used to plot the age of the patients treated over time and assess the presence of a potential significant trend via statistical correlation tests. RESULTS: A total of 280 studies including 83,437 UIAs treated between 1987 and 2021 met all eligibility criteria and were entered in the analysis. Mean age of the patients was 55.5 years, and 70.7% were female. There was a significant increasing trend in the age of the treated patients over time (Spearman r: 0.250; P < 0.001), with a 1-year increase in the average age of the treated patients every 5 years since 1987. CONCLUSIONS: The present study indicates that based on the treated UIA patient data published in the literature, older UIAs are being treated over time. This trend is likely driven by safer treatments while suggesting that re-evaluation of certain UIA treatment decision scores may be of great interest.

Trends in the size of treated unruptured intracranial aneurysms over 35 years.

OBJECTIVE: In the absence of clear guidelines and consistent natural history data, the decision to treat unruptured intracranial aneurysms (UIAs) is a matter of some controversy. Currently, decisions are often guided by a consensus of cerebrovascular specialist teams and patient preferences. It is unclear how paradigm-shifting developments in the detection and treatment of UIAs have affected the size of the UIAs that are selected for treatment. Herein, the authors aimed to study potential changes in the average size of the UIAs that were treated over time. They hypothesized that the average size of UIAs that are treated is decreasing over time. METHODS: A systematic search of the literature was performed to identify all studies describing the size of UIAs that were treated using any modality. Scatter diagrams with trend lines were used to plot the size of the aneurysms treated over time and assess for the presence of a potentially significant trend via statistical correlation tests. Subgroup analyses based on type of treatment, country of study, and specialty of the authors were performed. RESULTS: A total of 240 studies including 35,150 UIAs treated between 1987 and 2021 met all eligibility criteria and were entered in the analysis. The mean age of patients was 55.5 years, and 70.7% of the patients were females. There was a significant decrease in the size of treated UIAs over time (Spearman's r = -0.186, p < 0.001), with a 0.71-mm decrease in the average size of treated UIAs every 5 years since 1987 and an annual mean dropping below 7 mm in 2012. This decreasing trend was present in surgically and endovascularly treated UIAs (p < 0.001 for both), in more developed and developing countries (p < 0.001 for both), within neurosurgical and non-neurosurgical specialties (p < 0.001 for both), most prominently in the US (Spearman's r = -0.482, p < 0.001), and less prominently in Europe (Spearman's r = -0.221, p < 0.001) and was not detected in East Asia. CONCLUSIONS: The present study indicates that based on the treated UIA size data published in the literature over the past 35 years, smaller UIAs are being treated over time. This trend is likely driven by safer treatments. However, future studies should elucidate the cost-effectiveness of treating smaller UIAs as well as the possible real-world contribution of this trend in preventing aneurysmal subarachnoid hemorrhage.

Race as a factor in adverse outcomes following unruptured aneurysm surgery.

INTRODUCTION: Strong evidence demonstrates that race is associated with health outcomes. Previous neurosurgical research has focused predominantly on subjective data, such as patient satisfaction. Our objective was to assess whether racial disparities are present in primary objective outcomes for treatment of intracranial, unruptured aneurysms in the United States. METHODS: Data from the 2012-2015 National Inpatient Sample (NIS) database was analyzed. Patients who underwent either open or endovascular treatment of unruptured intracranial aneurysms were included (n = 11663). Patients were stratified by race, and those of unknown race or whose race sample size was too underpowered for analysis were excluded (n = 1202), along with those who experienced head trauma (n = 110) or concurrent AVM (n = 71). Poor outcome was defined as in-hospital mortality, discharge to a nursing facility or hospice, placement of a tracheostomy tube, or placement of a gastrostomy tube. The associations between race and adverse outcomes were determined through multivariate logistic regression, corrected for potentially confounding variables such as age, sex, procedural type, elective procedure, obesity, diabetes, tobacco, severity of illness, and hospital type. RESULTS: 7478 White, 1460 Black, 1086 Hispanic, and 279 Asian patients were included in the final analysis. Complication rates were not significantly different between races, however Black patients experienced the highest proportion of complications (24 %). After adjusting for confounders, the odds of poor outcomes were significantly higher for Black patients (OR = 1.32 95 % CI: 1.07-1.62; p = 0.008) when compared to White patients. Black and Hispanic patients demonstrated a longer length of stay (Black, B: 0.04; 95 % CI: 0.03, 0.06; p < 0.001; Hispanic, B: 0.04; 95 % CI: 0.02, 0.05; p < 0.001) when compared to White patients. CONCLUSION: Our nationwide analysis using the NIS suggests that Black patients treated for unruptured intracranial aneurysms experience worse outcomes and longer lengths of stay when compared to White patients. Recognizing the differences in objective outcomes and the presence of neurosurgical healthcare disparities is an important first step in providing equitable care to all patients. Future studies that carefully follow the social determinants of health and consider more confounding factors in the association between outcomes and determinants are needed.

Pipeline flex embolization device for the treatment of large unruptured posterior circulation aneurysms: Single-center experience.

PURPOSE: To investigate the safety and effect of the Pipeline Embolization Device (PED) Flex device in the treatment of large unruptured posterior circulation aneurysms in a single center. MATERIALS AND METHODS: Patients with large unruptured posterior circulation aneurysms which were treated with the PED Flex device were enrolled. The clinical, endovascular and follow-up data were analyzed, and the O'Kelly-Marotta (OKM) grading system was used to assess the aneurysm occlusion status. RESULTS: Fourteen patients with 14 large posterior circulation aneurysms who were treated with the PED Flex device were enrolled. The maximal diameter of aneurysm was 17.0 ± 3.9 mm. Fourteen PED Flex devices were deployed in 14 patients, with a technical success rate of 100%. All stents covered the aneurysm neck with good wall adherence and patent parent artery. Ten (71.4%) aneurysms were treated with a single PED Flex device each, and four (28.6%) patients experienced additional coiling. No neurological complications occurred in the periprocedural period. The mRS was 0 in eleven (78.6%) patients, 1 in two (14.3%), and 2 in one (7.1%) at discharge. All patients were followed up at 6-28 months (median 18), with an mRS score of 0 in all patients. Twelve (85.7%) patients experienced digital subtraction angiography 6-28 (median 18) months after the embolization procedure, and the OKM grade was D in nine (75%), C in two (16.7%), and B in one (8.3%). CONCLUSION: The Pipeline Flex Embolization Device can be safely applied to treat large unruptured posterior circulation aneurysms with a high complete aneurysm occlusion rate at follow-up.

Small vs. Large Unruptured Cerebral Aneurysm: Concerns With the Age of Patient.

Objective: The coiling and clipping of unruptured cerebral aneurysms (UCAs) in older patients has increased rapidly, and aneurysm size was a significant factor for decision-making in the treatment of UCAs. The purpose of the study was to investigate the impact of age on the functional outcomes of patients between the small versus large UCAs. Methods: We conducted a retrospective study for consecutive cases of UCAs admitted from May 2011 to December 2020. According to the maximum diameter of UCA, patients were divided into small UCAs (≤ 5 mm) group and large UCAs (>5 mm) group. Baseline characteristics, clinical complications, and outcomes of patients between the two groups were analyzed. Results: A total of 564 UCA patients received preventive treatment, including 165 small UCAs and 399 large UCAs. Compared with the small UCA group, the incidence of ischemia event in the large UCA group was significantly higher (7.3 vs. 2.4%; p = 0.029). Multivariable analysis demonstrating age (p = 0.006) and treatment modality (p < 0.001) were independent risk factors associated with poor outcome for patients with large UCAs. Conclusions: Preventive treatment of small UCAs is safe and effective, but older patients with large UCAs are at high risk of poor outcome, and the operations should be more cautious.

The Impact of Interhospital Competition on Treatment Strategy and Outcomes for Unruptured Intracranial Aneurysms.

BACKGROUND: Interhospital competition has been shown to affect surgical outcomes and expenditures. However, interhospital competition's impact on neurosurgery is poorly characterized. OBJECTIVE: To assess how interhospital competition is associated with treatment strategy and outcomes for unruptured intracranial aneurysms (UIAs). METHODS: We identified all elective UIA admissions in the National Inpatient Sample from 2002 to 2011. Competitive intensity of each hospital market was quantified using the validated Herfindahl-Hirschman Index (HHI), with lower values denoting higher competition. We then obtained nationwide HHI values for 2012 to 2016 from the Health Care Cost Project. Outcomes included treatment modality (clipping, coiling, or nonoperative management), inpatient mortality, disposition, complications, length of stay (LOS), and costs. Multivariate regression assessed the association between HHI and outcomes, controlling for patient demographics, severity metrics, hospital characteristics, and treatment. RESULTS: We studied 157 979 elective UIA admissions at 1435 hospitals from 2002 to 2011, with an increase in coiling admissions (13.4% to 33.7%) and decrease in clipping admissions (30.9% to 17.6%). Mean hospital HHI was 0.11 (range = 0.001-0.97). Competition decreased for 61.8% of hospitals from 2002 to 2011 and 68.1% of metropolitan localities from 2012 to 2016. Admissions in more competitive hospital markets exhibited increased odds of undergoing surgery (odds ratio [OR] = 1.37, P < .001), with preference toward coiling over clipping (OR = 1.27, P < .001). HHI was not associated with mortality, disposition, or LOS. However, increased interhospital competition was associated with more complications (OR = 1.09, P = .001) and greater hospital costs (ß-coefficient = 1.06, P < .001). CONCLUSION: For UIA patients, admission to hospitals in more competitive geographies was associated with increased rates of surgical intervention, coiling utilization, complications, and hospitalization costs.

Management of Unruptured Intracranial Aneurysms.

Unruptured intracranial aneurysms (UIAs) are common and are being detected with increasing frequency given the improved quality and higher frequency of cross-sectional imaging. The long-term natural history of UIAs remains poorly understood. To date, there is relative lack of clear guidelines for selection of patients with UIAs for treatment. Surveillance imaging for untreated UIAs is frequently performed, but frequency, duration, and modality of surveillance imaging need clearer guidelines. The authors review the current evidence on prevalence, natural history, role of treatment, and surveillance and screening imaging and highlight the areas for further research.

Unruptured aneurysms: Why observational studies fall short no matter how "Big" the Data.

BACKGROUND: The best management of unruptured intracranial aneurysms (UIAs) remains unknown, despite multiple observational studies. A randomized trial (RCT) is in order. Yet, a National Institute Neurological Disorders and Stroke workshop has once again proposed to use prospective observational studies (POS) of large databases to address such problems. METHODS: We review the historical misconceptions that have been associated with observations of UIAs and their treatments. We critically examine some recent methods that have been proposed to address shortcomings of observational studies. We finally review the ethical principles underlying the use of trial methods in the care of patients. RESULTS: Replacing RCTs with POS submits patients to management options that have never been proven beneficial, while making them involuntary research subjects of studies that are inevitably biased. A science of practice cannot be an outsider's examination of the behavior of clinicians incapable of questioning their practice. The thesis we propose is that a science of practice must not only eventually determine what best practice will be; It must engage agents involved in medical practice to transparently reveal the uncertainty that calls for management options to be offered under the guidance of declared and controlled care research, to optimize patient outcomes in spite of the uncertainty. CONCLUSION: To use POS rather than RCTs in medical practice is to renege on scientific and ethical principles that characterize modern medicine. Instead, we must learn to integrate care research into our practice to provide optimal medical care in real time.

Trends of Ruptured and Unruptured Aneurysms Treatment in the United States in Post-ISAT Era: A National Inpatient Sample Analysis.

Background The ISAT (International Subarachnoid Aneurysm Trial) has generated a paradigm shift towards endovascular treatment for intracranial aneurysms but remains unclear if this has led to a true reduction in the risk for aneurysmal subarachnoid hemorrhage (aSAH). We sought to study the association between the treatment burden of unruptured and ruptured aneurysms in the post-ISAT era. Methods and Results Admissions data from the National Inpatient Sample (2004-2014) were extracted, including patients with a primary diagnosis of aSAH or unruptured intracranial aneurysms treated by clipping or coiling. Within each year, this combined group was randomly matched to non-aneurysmal control group, based on age, sex, and Elixhauser comorbidity index. Multinomial regression was performed to calculate the relative risk ratio of undergoing treatment for either ruptured or unruptured aneurysms in comparison with the reference control group, adjusted for time. After adjusting for National Inpatient Sample sampling effects, 243 754 patients with aneurysm were identified, 174 580 (71.6%) were women; mean age, 55.4±13.2 years. A total of 121 882 (50.01%) patients were treated for unruptured aneurysms, 79 627 (65.3%) endovascularly and 42 256 (34.7%) surgically. A total of 121 872 (49.99%) patients underwent procedures for aSAH, 68 921 (56.6%) endovascular, and 52 951 (43.5%) surgically. Multinomial regression revealed a significant year-to-year decrease in aSAH procedures compared with the control group of non-aneurysmal hospitalizations (relative risk ratio, 0.963 per year; P<0.001), while there was no statistical significance for unruptured aneurysms procedures (relative risk ratio, 1.012 per year; P=0.35). Conclusions With each passing year, there is a significant decrease in relative risk ratio of undergoing treatment for aSAH, concomitant with a stable annual risk of undergoing treatment for unruptured intracranial aneurysms.

Early versus Delayed Microsurgical Clipping of Additional Unruptured Aneurysms in Patients with Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: The optimal timing for the surgical treatment of additional unruptured aneurysms in patients with multiple aneurysms and aneurysmal subarachnoid hemorrhage (aSAH) is unknown. Therefore, we analyzed the results of early versus delayed microsurgical treatment of unruptured aneurysms when multiple aneurysms were present in the setting of aSAH. METHODS: The medical records from a consecutive, single-surgeon, 19-year experience of all patients with aSAH and additional unruptured aneurysms treated with a second surgery were reviewed retrospectively. Early treatment was defined as treatment within 30 days and delayed treatment as treatment more than 30 days after the initial surgery for aSAH. RESULTS: A total of 85 patients with aSAH and multiple aneurysms were identified. Early (n = 55; 65%) or delayed (n = 30; 35%) clipping was performed for additional unruptured aneurysms. Intraoperative rupture (P = 0.028), higher Fisher grade (P = 0.046), multiple additional unruptured aneurysms (P = 0.04), and large aneurysm size of either the ruptured aneurysm (P = 0.034) or unruptured aneurysm (P = 0.022) were significant factors favoring early treatment. Significant differences were not observed with respect to outcome (modified Rankin scale), unfavorable modified Rankin scale changes between the first surgery and last follow-up, aneurysm occlusion, and shunt-dependent hydrocephalus. No ruptures of untreated aneurysms during the follow-up course were observed. CONCLUSIONS: Both early and delayed surgical treatment of unruptured aneurysms in the setting of aSAH are safe. Factors prompting earlier intervention might include multiple additional aneurysms, larger aneurysms, and intraoperative aneurysm rupture, which could suggest a destabilized arterial wall. Delayed treatment is advisable for patients with a poor clinical presentation, greater underlying brain injury, and a swollen brain requiring decompressive craniectomy to allow time for recovery.

Long-term aneurysm recurrence and de novo aneurysm formation after surgical treatment of unruptured intracranial aneurysms: a cohort study and systematic review.

Objective: There is a relative lack of literature on long-term aneurysm recurrence and de novo aneurysm formation following surgical treatment of unruptured intracranial aneurysms. This retrospective single-center cohort study, therefore, analyzes the incidence of aneurysm recurrence, and the incidence of de novo aneurysms formation in patients with at least 10yrs of radiological follow-up. The data are put into the context of a systematic review of the literature.Methods: Patients that underwent surgical treatment of an unruptured intracranial aneurysm at the Basel University Hospital were retrospectively identified. The rate of recurrent or de novo aneurysm formation was assessed for all patients with imaging follow-up ≥10yrs. A systematic review including studies with a mean follow-up period of ≥10yrs was then performed.Results: A total of 95 patients had undergone surgical treatment of an unruptured intracranial aneurysm between 1994 and 2008. Twenty-one patients (22.1%) had available imaging follow-up ≥10yrs (mean: 13.1yrs). In these patients, aneurysm recurrence and de novo aneurysm formation were equally found in 23.8% (n = 5; 1.8%/yr). There was no case of aneurysm rupture from a recurrent or a de novo aneurysm. The systematic literature review covered a combined cohort of 1778 patients over a mean follow-up period of 14.0yrs. In this cohort, the aneurysm recurrence rate was 16.4% (0.7%/yr), and the rate of de novo aneurysm formation was 6.2% (0.4%/yr).Discussion: Despite some discrepancy regarding the incidence, both cohorts show a non-negligible long-term risk of aneurysm recurrence and de novo aneurysm formation, which warrants life-long imaging follow-up.Abbreviations: SD: standard deviation; DSA: digital subtraction angiography; CTA: computed tomography angiography; MRA: magnetic resonance angiography; MCA: middle cerebral artery; ACA: anterior cerebral artery; ACommA: anterior communicating artery; ICA: internal carotid artery; ADPKD: autosomal dominant polycystic kidney disease; MeSH: Medical Subject Headings.

Use of our Protocol of Multimodality Tools to Aid in the Safe Microsurgical Clipping of Unruptured Anterior Circulation Aneurysms.

OBJECTIVES: The aim of this study is to analyze the effectiveness of our protocol of the use of multimodality tools, namely indocyanine green-dual image video angiography, neuroendoscope, neuromonitoring with motor-evoked potential, micro-Doppler in the microsurgical clipping of unruptured anterior circulation aneurysms, operated at our institute from January 2016 to December 2018. MATERIALS AND METHODS: We performed a retrospective analysis of all cases of unruptured anterior circulation aneurysms, operated at Fujita Health University Banbuntane-Hotokukai Hospital, Japan, from January 2016 to December 2018. We assessed outcome at immediate postoperative, at discharge, and at 3 months follow-up by defining permanent morbidity as drop in Modified Rankin Scale (MRS) by 1 at 3 months follow-up and transient morbidity as temporary deficit that improved at discharge or follow-up. Postoperative events, namely seizures, infection that did not affect/change. Preoperative MRS and discharge timing were excluded. We concluded poor outcome as MRS ≥3 and good outcome as MRS < 3 (0-2). All patients had a minimum of 3 months follow-up before outcome conclusion. RESULTS: In 2016, a total of 98 cases were operated with no mortality or permanent morbidity (i.e., change in preoperative MRS), only transient morbidity was seen in (two cases) 2.04%. In 2017, a total of 119 cases were operated with no mortality or morbidity. In 2018, a total of 130 cases were operated with no mortality or permanent morbidity, only transient morbidity 0.7%. Summarizing from January 2016 to December 2018, a total of 347 cases of anterior circulation aneurysms were operated. Mostly, in the female sex (73.3%), the most common was middle cerebral artery aneurysm (39.1%). The mean size was 5.3 mm with no mortality or permanent morbidity with only transient morbidity in 0.9%. No poor outcome (MRS ≥3) was seen in our series. CONCLUSION: In our center for most unruptured anterior circulation aneurysms, microsurgical clipping is the treatment of choice. We believe our protocol of the intra-operative usage of multimodality tools have aided in the safe microsurgical clipping and have consistently resulted in good operative outcomes. Hence, we recommend and continue to use our Fujita-Bantane Protocol in all cases of micro-surgical clipping of aneurysms to consistently achieve good operative outcomes.

Cavernous carotid artery aneurysms on a single institution: An epidemiological study with 201 patients.

OBJECTIVES: Cavernous carotid aneurysms (CCA) represent 2-9% of all intracranial aneurysms. For long considered benign lesions, these entities are unique when it comes to clinical presentation and management. Usually asymptomatic, CCAs can grow and rupture causing different manifestations. The lack of a long-term assessment of both treated and untreated CCAs' natural history justifies why there is no consensus regarding what are the recommended therapeutic measures. While some advocate that an intervention is always necessary, others consider that patients deserve an individualized evaluation. PATIENTS AND METHODS: We describe our single-institution experience in diagnosis, follow-up, and management of 201 CCAs. In addition, we evaluate the association of giant CCAs with aneurysms in other locations using a Chi-square test. RESULTS: 201 patients had 245 CCAs. 92% of the patients were women. The mean age at diagnosis was 61 years. Concomitant aneurysms were observed in 53.2% of the patients, and the middle cerebral artery was the most affected artery. 66 (30.6%) CCAs were considered "giant", and the follow-up period ranged from 1 to 23 years.The presence of a giant CCA seemed to hinder other aneurysms' formation - RR 0.47 (IC 95% 0.31-0.67), p < 0.0001. CONCLUSIONS: CCAs should be individually assessed. A conservative approach ought to be adopted for asymptomatic and oligosymptomatic lesions. Finally, a multidisciplinary team must evaluate the other situations, in order to define whether the microsurgical or the endovascular treatment is better option. Presence of a giant lesion within the cavernous sinus is associated with less occurrence of other aneurysms.

Introduction of intraoperative neuromonitoring does not necessarily improve overall long-term outcome in elective aneurysm clipping.

OBJECTIVE: Intraoperative neuromonitoring (IOM), particularly of somatosensory-evoked potentials (SSEPs) and motor-evoked potentials (MEPs), evolved as standard of care in a variety of neurosurgical procedures. Case series report a positive impact of IOM for elective microsurgical clipping of unruptured intracranial aneurysms (ECUIA), whereas systematic evaluation of its predictive value is lacking. Therefore, the authors analyzed the neurological outcome of patients undergoing ECUIA before and after IOM introduction to this procedure. METHODS: The dates of inclusion in the study were 2007-2014. In this period, ECUIA procedures before (n = 136, NIOM-group; 2007-2010) and after introduction of IOM (n = 138, IOM-group; 2011-2014) were included. The cutoff value for SSEP/MEP abnormality was chosen as an amplitude reduction ≥ 50%. SSEP/MEP changes were correlated with neurological outcome. IOM-undetectable deficits (bulbar, vision, ataxia) were not included in risk stratification. RESULTS: There was no significant difference in sex distribution, follow-up period, subarachnoid hemorrhage risk factors, aneurysm diameter, complexity, and location. Age was higher in the IOM-group (57 vs 54 years, p = 0.012). In the IOM group, there were 18 new postoperative deficits (13.0%, 5.8% permanent), 9 hemisyndromes, 2 comas, 4 bulbar symptoms, and 3 visual deficits. In the NIOM group there were 18 new deficits (13.2%; 7.3% permanent, including 7 hemisyndromes). The groups did not significantly differ in the number or nature of postoperative deficits, nor in their recovery rate. In the IOM group, SSEPs and MEPs were available in 99% of cases. Significant changes were noted in 18 cases, 4 of which exhibited postoperative hemisyndrome, and 1 suffered from prolonged comatose state (5 true-positive cases). Twelve patients showed no new detectable deficits (false positives), however 2 of these cases showed asymptomatic infarction. Five patients with new hemisyndrome and 1 comatose patient did not show significant SSEP/MEP alterations (false negatives). Overall sensitivity of SSEP/MEP monitoring was 45.5%, specificity 89.8%, positive predictive value 27.8%, and negative predictive value 95.0%. CONCLUSIONS: The assumed positive impact of introducing SSEP/MEP monitoring on overall neurological outcome in ECUIA did not reach significance. This study suggests that from a medicolegal point of view, IOM is not stringently required in all neurovascular procedures. However, future studies should carefully address high-risk patients with complex procedures who might benefit more clearly from IOM than others.

National trends in cerebral bypass for unruptured intracranial aneurysms: a National (Nationwide) Inpatient Sample analysis of 1998-2015.

OBJECTIVEThe development and recent widespread dissemination of flow diverters may have reduced the utilization of surgical bypass procedures to treat complex or giant unruptured intracranial aneurysms (UIAs). The aim of this retrospective cohort study was to observe trends in cerebral revascularization procedures for UIAs in the United States before and after the introduction of flow diverters by using the National (Nationwide) Inpatient Sample (NIS).METHODSThe authors extracted data from the NIS database for the years 1998-2015 using the ICD-9/10 diagnostic and procedure codes. Patients with a primary diagnosis of UIA with a concurrent bypass procedure were included in the study. Outcomes and hospital charges were analyzed.RESULTSA total of 216,212 patients had a primary diagnosis of UIA during the study period. The number of patients diagnosed with a UIA increased by 128% from 1998 (n = 7718) to 2015 (n = 17,600). Only 1328 of the UIA patients (0.6%) underwent cerebral bypass. The percentage of patients who underwent bypass in the flow diverter era (2010-2015) remained stable at 0.4%. Most patients who underwent bypass were white (51%), were female (62%), had a median household income in the 3rd or 4th quartiles (57%), and had private insurance (51%). The West (33%) and Midwest/North Central regions (30%) had the highest volume of bypasses, whereas the Northeast region had the lowest (15%). Compared to the period 1998-2011, bypass procedures for UIAs in 2012-2015 shifted entirely to urban teaching hospitals (100%) and to an elective basis (77%). The median hospital stay (9 vs 3 days, p < 0.0001), median hospital charges ($186,746 vs $66,361, p < 0.0001), and rate of any complication (51% vs 17%, p < 0.0001) were approximately threefold higher for the UIA patients with bypass than for those without bypass.CONCLUSIONSDespite a significant increase in the diagnosis of UIAs over the 17-year study period, the proportion of bypass procedures performed as part of their treatment has remained stable. Therefore, advances in endovascular aneurysm therapy do not appear to have affected the volume of bypass procedures performed in the UIA population. The authors' findings suggest a potentially ongoing niche for bypass procedures in the contemporary treatment of UIAs.

Genetic Risk Factors for Intracranial Aneurysm in the Kazakh Population.

An intracranial aneurysm (IA) is a weak or thin area on a blood vessel in the brain that balloons as it fills with blood. Genetic factors can influence the risk of developing an aneurism. The purpose of this study was to explore the relationship between single nucleotide polymorphisms (SNPs) and IA in Kazakh population. The patients were genotyped for 60 single nucleotide polymorphisms. Genotyping was performed on the QuantStudio 12K Flex (Life Technologies). A linear regression analysis found 13 SNPs' significant association with development and rupture of IA: the rs1800956 polymorphism of the ENG gene, rs1756 46 polymorphism of the JDP2 gene, variant rs1800255 of the COL3A1, rs4667622 of the UBR3, rs2374513 of the c12orf75, rs3742321 polymorphism of the StAR, the rs3782356 polymorphism of MLL2 gene, rs3932338 to 214 kilobases downstream of PRDM9, rs7550260 polymorphism of the ARHGEF, rs1504749 polymorphism of the SOX17, the rs173686 polymorphism of CSPG2 gene, rs6460071 located on LIMK1 gene, and the rs4934 polymorphism of SERPINA3. A total of 13 SNPs were identified as potential genetic markers for the development and risk of rupture of aneurysms in the Kazakh population. Similar results were obtained after adjusting for the confounding factors of arterial hypertension and age.

Risk of de novo aneurysm formation in patients with a prior diagnosis of ruptured or unruptured aneurysm: systematic review and meta-analysis.

OBJECTIVE: De novo aneurysms are rare entities periodically discovered during follow-up imaging. Little is known regarding the frequency with which these lesions form or the time course. This systematic review and meta-analysis was undertaken to estimate the incidence of de novo aneurysms and to determine risk factors for aneurysm formation. METHODS: The authors searched multiple databases for studies of patients with unruptured and ruptured aneurysms describing the rate of de novo aneurysm formation. The primary outcome was incidence of de novo aneurysm formation. A meta-analysis was performed using a random-effects model. The authors examined the associations of multiple aneurysms, prior subarachnoid hemorrhage, smoking, sex, age at presentation, and hypertension with de novo aneurysm formation. RESULTS: The meta-analysis included 14,968 aneurysm patients who received imaging follow-up from 35 studies. The overall incidence of de novo aneurysm formation was 2% (95% CI 2%-3%) over a mean follow-up time of 8.3 years. The estimated incidence density was 0.3%/patient-year. There was no statistically significant difference in rates of de novo aneurysm formation between patients who had ruptured aneurysms and those with unruptured aneurysms. In 8 studies, 11.2% of de novo aneurysms were found in patients with ≤ 5 years of follow-up and 88.8% were found at > 5 years. The mean time to rupture for de novo aneurysms was 10 years. CONCLUSIONS: This systematic review demonstrates that formation of de novo aneurysms is rare. Overall, routine screening for de novo aneurysms is likely to be of low yield and could be performed at time intervals of at least 5 to 10 years.