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

Association of geographical disparities and segregation in regional treatment facilities for Black patients with aneurysmal subarachnoid hemorrhage in the United States

Background and objectives

This study investigates geographic disparities in aneurysmal subarachnoid hemorrhage (aSAH) care for Black patients and aims to explore the association with segregation in treatment facilities. Understanding these dynamics can guide efforts to improve healthcare outcomes for marginalized populations.

Methods

This cohort study evaluated regional differences in segregation for Black patients with aSAH and the association with geographic variations in disparities from 2016 to 2020. The National Inpatient Sample (NIS) database was queried for admission data on aSAH. Black patients were compared to White patients. Segregation in treatment facilities was calculated using the dissimilarity (D) index. Using multivariable logistic regression models, the regional disparities in aSAH treatment, functional outcomes, mortality, and end-of-life care between Black and White patients and the association of geographical segregation in treatment facilities was assessed.

Results

142,285 Black and White patients were diagnosed with aSAH from 2016 to 2020. The Pacific division (D index = 0.55) had the greatest degree of segregation in treatment facilities, while the South Atlantic (D index = 0.39) had the lowest. Compared to lower segregation, regions with higher levels of segregation (global F test p < 0.001) were associated a lower likelihood of mortality (OR 0.91, 95% CI 0.82-1.00, p = 0.044 vs. OR 0.75, 95% CI 0.68-0.83, p < 0. 001) (p = 0.049), greater likelihood of tracheostomy tube placement (OR 1.45, 95% CI 1.22-1.73, p < 0.001 vs. OR 1.87, 95% CI 1.59-2.21, p < 0.001) (p < 0. 001), and lower likelihood of receiving palliative care (OR 0.88, 95% CI 0.76-0.93, p < 0.001 vs. OR 0.67, 95% CI 0.59-0.77, p < 0.001) (p = 0.029).

Conclusion

This study demonstrates regional differences in disparities for Black patients with aSAH, particularly in end-of-life care, with varying levels of segregation in regional treatment facilities playing an associated role. The findings underscore the need for targeted interventions and policy changes to address systemic healthcare inequities, reduce segregation, and ensure equitable access to high-quality care for all patients.

Changes in treatment of intracranial aneurysms during the last decade in a large European neurovascular center

OBJECTIVE

Treatment modality for ruptured and unruptured intracranial aneurysms has shifted during the last two decades from microsurgical treatment towards endovascular treatment. We present how this transition happened in a large European neurovascular center.

METHODS

We conducted a retrospective observational study consecutive patients treated for an unruptured or ruptured intracranial aneurysm at Helsinki University Hospital during 2012-2022. We used Poisson regression analysis to report age-adjusted treatment trends by aneurysm location and rupture status.

RESULTS

A total of 2491 patients with intracranial aneurysms were treated (44% ruptured, 56% unruptured): 1421 (57%) surgically and 1070 (43%) endovascularly. A general trend towards fewer treated aneurysms was noted. The proportion of patients treated surgically decreased from 90% in 2012 to 20% in 2022. The age-adjusted decrease of surgical versus endovascular treatment was 6.9%/year for all aneurysms, 6.8% for ruptured aneurysms, and 6.8% for unruptured aneurysms. The decrease of surgical treatment was most evident in unruptured vertebrobasilar aneurysms (10.8%/year), unruptured communicating artery aneurysms (10.1%/year), ruptured communicating artery aneurysms (10.0%/year), and ruptured internal carotid aneurysms (9.0%/year). There was no change in treatment modality for middle cerebral artery aneurysms, of which 85% were still surgically treated in 2022. A trend towards an increasing size for treated ruptured aneurysms was found (p = 0.033).

CONCLUSION

A significant shift of the treatment modality from surgical to endovascular treatment occurred for all aneurysm locations except for middle cerebral artery aneurysms. Whether this shift has affected long-term safety and patient outcomes should be assessed in the future.

Cerebral aneurysms: Germany-wide real-world outcome data of endovascular or neurosurgical treatment from 2007 to 2019

BACKGROUND

Evidence on clinical outcome after endovascular treatment (EVT) vs neurosurgical clipping of intracranial aneurysms (IAs) is based on one randomized and one pseudo-randomized trial for ruptured aneurysms. Herein, we analyze nationwide real-world hospital outcomes after EVT vs clipping of ruptured and unruptured IAs.

METHODS

This cohort study analyzed all EVT and clipping procedures for IAs in Germany between 2007 and 2019. The data basis was the billing-data of all German hospitals from the German Federal Statistical Office. EVT and clipping interventions, comorbidities, and in-hospital outcomes were identified using International Classification of Diseases (ICD) and Operation and Procedure (OPS) codes. Discharge type was used as a surrogate marker for functional independence. Poor clinical outcome at discharge was additionally defined by the dichotomous US National Inpatient Sample-Subarachnoid hemorrhage Outcome Measure score (NIH-SOM). Secondary outcomes included length of hospital stay, prolonged mechanical ventilation (>48 hour), and hospital reimbursement.

RESULTS

We analyzed 90 039 procedures (62.6% EVT, 35.52% clipping, 1.8% combined) for the treatment of IAs. After adjustment in-hospital mortality was equal after EVT compared with clipping, in ruptured IAs (adjusted OR (aOR) 0.98, p=0.707) and unruptured IAs (aOR 0.92, p=0.482). Functional independence was more likely after EVT for ruptured (aOR 0.81, p<0.001) and unruptured IAs (aOR 0.4, p<0.001). Poor clinical outcome was more likely after clipping for ruptured (aOR 0.67, p<0.001) and unruptured IAs (aOR 0.56, p<0.001).

CONCLUSIONS

In German clinical practice, we observed higher rates of functional independence and lower rates of poor outcomes at discharge with equal mortality for EVT.

Epidemiology and treatment of atraumatic subarachnoid hemorrhage over 10 years in a population-based registry

INTRODUCTION

Incidence of atraumatic subarachnoid hemorrhage (SAH) is decreasing over time and its treatment is changing. We reported epidemiologic data on aneurysmal (a-) and non-aneurysmal (na-) SAH over 10 years.

PATIENTS AND METHODS

Our prospective population-based registry included patients with first-ever SAH occurring from January 2011 to December 2020. Clinical and neuroimaging records were screened to evaluate the presence and location of intracranial aneurysms, to identify naSAH subtypes and to retrieve information on surgical treatments. Incidence rates were standardized to the 2011 Italian and European population. We also estimated 30-day and 1-year case-fatality rates after SAH. Multivariate hazard ratios for 30-days and 1-year fatality were estimated with Cox regression analysis.

RESULTS

194 patients (60.8% women; mean age 62.5 ± 16.0 years) were included (76.8% aSAH and 23.2% naSAH). The crude incidence rates per 100,000 person-years of SAH, aSAH, and naSAH were 6.5 (95% CI 5.6-7.5), 5.0 (95% CI 4.2-5.9), and 1.5 (95% CI 1.1-2.0), respectively, and remained stable over time. Compared to aSAH, naSAH patients had higher age (68.8 ± 19.7 yearsvs 60.6 ± 14.2 years; p = 0.012), lower cigarette smoking (17.9%vs 36.4%; p < 0.001) and higher atrial fibrillation (15.7% vs 2.8%; p = 0.005). SAH case-fatality rates within 30-days and 1-year were 28.4% (95% CI 21.4-36.9) and 37.1% (95% CI 29.0-46.7), respectively. The relative proportion of surgically treated patients did not change over time.

CONCLUSION

We found a low and stable incidence of SAH over the 2011-2020 period. naSAH remained rare and deserves further investigation in larger prospective cohorts.

Clinical management of contrast-induced neurotoxicity: a systematic review

BACKGROUND

Contrast-induced neurotoxicity (CIN) is an increasingly recognised complication following endovascular procedures utilising contrast. It remains poorly understood with heterogenous clinical management strategies. The aim of this review was to identify commonly employed treatments for CIN to enhance clinical decision making.

METHODS

A systematic search of Embase (1947-2022) and Medline (1946-2022) was conducted. Articles describing (i) patients with a clinical diagnosis of CIN, (ii) with radiological exclusion of other pathologies, (iii) detailed report of treatments, and (iv) discharge outcomes, were included. Data relating to demographics, procedure, symptoms, treatment and outcomes were extracted.

RESULTS

A total of 73 patients were included, with a median age of 64 years. The most common procedures were cerebral angiography (42.5%) and coronary angiography (42.5%), and the median volume of contrast administered was 150 ml. The most common symptoms were cortical blindness (38.4%) and reduced consciousness (28.8%), and 84.9% of patients experienced complete resolution at the time of discharge. Management included intravenous fluids to dilute contrast in the cerebrovasculature (54.8%), corticosteroids to reduce blood-brain barrier damage (47.9%), antiseizure (16.4%) and sedative (16.4%) medications. Mannitol (13.7%) was also utilised to reduce cerebral oedema. Intensive care admission was required for 19.2% of patients. No statistically significant differences were observed between treatment and discharge outcomes.

CONCLUSIONS

The clinical management of CIN should be considered on a patient-by-patient basis, but may consist of aggressive fluid therapy alongside corticosteroids, as well as other supportive therapy as required. Further examination of CIN management is required to define best practice.

A Novel Braided Stent With Customized Simulation Software for Treatment of Intracranial Aneurysms: Multicenter Prospective Trial Before Unrestricted Clinical Application

BACKGROUND AND OBJECTIVES

Planning/guidance software became important tools for physicians' presurgical optimal decision-making. However, there are no intracranial stent products with specifically associated simulation software. We report the "premarket" clinical trial of a new braided stent with a customized simulation software.

METHODS

A stent system with 3 mesh density types (16, 24, and 32 wire mesh) was designed based on computational flow dynamics technology, and a simulation software (virtual stent planner [VSP]) was developed for the optimal stent deployment planning. Stents were selected after simulation on preoperative 3D-processed angioimages, and accuracy of the VSP was evaluated.

RESULTS

Thirty-three unruptured intracranial aneurysms were successfully treated with VSP guidance. Twenty aneurysms (61%) were anterior circulation aneurysms, and 13 (39%) were posterior circulation aneurysms. The average aneurysm size was 7.1 mm, and the mean follow-up period was 19.2 months (11-39.0). There was no major recurrence or retreatment during follow-up, 2 morbidity cases, and no mortality. VSP planning presented slightly smaller stent dimensions compared with postdeployment: 24.2 vs 25.5 mm average, error -1.3 mm, and difference rate-5.46%.

CONCLUSION

Based on this result, the new stents and software guidance system were approved by the Ministry of Health and Welfare as a combined medical device. VSP provided precise deployment with minimal error compared with actual stent and can contribute to better stent deployment even for less experienced physicians.

Woven EndoBridge versus stent-assisted coil embolization for the treatment of ruptured wide-necked aneurysms: A multicentric experience

BACKGROUND

The potentially higher risk of hemorrhagic complications is of concern in stent-assisted coiling (SAC) of ruptured wide-necked intracranial aneurysms (IAs). The Woven EndoBridge (WEB) is considered an appealing alternative since antiplatelet therapy is not required. Herein, we aimed to compare the safety and effectiveness of WEB vs. SAC for the treatment of ruptured wide-necked IAs.

METHODS

This was an international cross-sectional study of consecutive patients treated for ruptured wide-neck IAs with WEB or SAC at four high-volume neurovascular centers between 2019 and 2022. Primary and secondary efficacy outcomes were radiographic aneurysm occlusion at follow-up and functional status at last follow-up. Safety outcomes included periprocedural hemorrhagic/ischemia-related complications.

RESULTS

One hundred five patients treated with WEB and 112 patients treated with SAC were included. The median procedure duration of endovascular treatment was shorter for WEB than for SAC (69 vs. 76 min; p = 0.04). There were no significant differences in complete aneurysm occlusion rates (SAC: 64.5% vs. WEB: 60.9%; adjusted OR [aOR] = 0.70; 95%CI 0.34-1.43; p = 0.328). SAC had a significantly higher risk of complications (23.2% vs. 9.5%, p = 0.009), ischemic events (17% vs. 6.7%, p = 0.024), and EVD hemorrhage (16% vs. 0%, p = 0.008). The probability of procedure-related complications across procedure time was significantly lower with WEB compared with SAC (aOR = 0.40; 95%CI 0.20-1.13; p = 0.03).

CONCLUSION

WEB and SAC demonstrated similar obliteration rates at follow-up when used for embolization of ruptured wide-necked IAs. However, SAC showed higher rates of procedure-related complications primarily driven by ischemic events and higher rates of EVD hemorrhage. The overall treatment duration was shorter for WEB than for SAC.

Pre-treatment re-bleeding following aneurysmal subarachnoid hemorrhage: A systematic review of published prediction models with risk of bias and clinical applicability assessment

BACKGROUND

Pre-treatment rebleeding following aneurysmal subarachnoid hemorrhage (aSAH) increases the risk of death and a poor neurological outcome. Current guidelines recommend aneurysm treatment "as early as feasible after presentation, preferably within 24 h of onset" to mitigate this risk, a practice termed ultra-early treatment. However, ongoing debate regarding whether ultra-early treatment is independently associated with reduced re-bleeding risk, together with the recognition that re-bleeding occurs even in centres practicing ultra-early treatment due to the presence of other risk-factors has resulted in a renewed need for patient-specific re-bleed risk prediction. Here, we systematically review models which seek to provide patient specific predictions of pre-treatment rebleeding risk.

METHODS

Following registration on the International prospective register of systematic reviews (PROSPERO) CRD 42023421235; Ovid Medline (Pubmed), Embase and Googlescholar were searched for English language studies between 1st May 2002 and 1st June 2023 describing pre-treatment rebleed prediction models following aSAH in adults ≥18 years. Of 763 unique records, 17 full texts were scrutinised with 5 publications describing 4 models reviewed. We used the semi-automated template of Fernandez-Felix et al. incorporating the Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies (CHARMS) checklist and the Prediction model Risk Of Bias ASsessment Tool (PROBAST) for data extraction, risk of bias and clinical applicability assessment. To further standardize risk of bias and clinical applicability assessment, we also used the published explanatory notes for the PROBAST tool and compared the aneurysm treatment practices each prediction model's formulation cohort experienced to a prespecified benchmark representative of contemporary aneurysm treatment practices as outlined in recent evidence-based guidelines and published practice pattern reports from four developed countries.

RESULTS

Reported model discriminative performance varied between 0.77 and 0.939, however, no single model demonstrated a consistently low risk of bias and low concern for clinical applicability in all domains. Only the score of Darkwah Oppong et al. was formulated using a patient cohort in which the majority of patients were managed in accordance with contemporary, evidence-based aneurysm treatment practices defined by ultra-early and predominantly endovascular treatment. However, this model did not undergo calibration or clinical utility analysis and when applied to an external cohort, its discriminative performance was substantially lower that reported at formulation.

CONCLUSIONS

No existing prediction model can be recommended for clinical use in centers practicing contemporary, evidence-based aneurysm treatment. There is a pressing need for improved prediction models to estimate and minimize pre-treatment re-bleeding risk.

A review and journey in intrasaccular treatment of intracranial aneurysms

The invested effort and collaboration of clinicians and medical device companies to improve occlusion rates and clinical outcomes for patients with intracranial aneurysms treated via less invasive endovascular means led to the development of the concept of intrasaccular devices. Intrasaccular devices were introduced to offer simple treatment options, offering easier navigation through difficult anatomy, simpler and quicker deployment into large and wide-neck aneurysms. Additionally, they offer easier sizing, whilst offering a wide range of options suitable for aneurysms of different sizes. The concept of most intrasaccular devices is to occupy the aneurysm neck, however offering better stability than simple coiling, therefore increasing the chance of long-term aneurysm occlusion. This is achieved without a sizable metal content within the parent vessel, contrary to flow diverters, theoretically reducing the risk of thromboembolic events. This review aims to discuss the history and latest developments of intrasaccular intracranial devices, which offer an exciting and potentially successful option for treatment of complex intracranial aneurysms.

Endovascular and Medical Management of Unruptured Intracranial Aneurysms

Unruptured intracranial aneurysms are often discovered incidentally on noninvasive imaging. As use of noninvasive imaging has increased, our understanding of the presumed prevalence of intracranial aneurysms in adults has increased. Incidentally found aneurysms are often asymptomatic; however, they can rarely rupture and cause life-threatening illness. Elective treatment of intracranial aneurysms carries risks which need to be considered along with patient-specific factors (e.g., anatomy, medical comorbidities, personal preferences). In this article, we review the natural history, risk factors for cerebral aneurysm formation and rupture, evidence for medical management, and the safety profile and efficacy of available endovascular treatment options.

Biomimetic tissue phantoms for neurosurgical near-infrared fluorescence imaging

SIGNIFICANCE

Neurosurgical fluorescence imaging is a well-established clinical approach with a growing range of indications for use. However, this technology lacks effective phantom-based tools for development, performance testing, and clinician training.

AIM

Our primary aim was to develop and evaluate 3D-printed phantoms capable of optically and morphologically simulating neurovasculature under fluorescence angiography.

APPROACH

Volumetric digital maps of the circle of Willis with basilar and posterior communicator artery aneurysms, along with surrounding cerebral tissue, were generated. Phantoms were fabricated with a stereolithography printer using custom photopolymer composites, then visualized under white light and near-infrared fluorescence imaging.

RESULTS

Feature sizes of printed components were found to be within 13% of digital models. Phantoms exhibited realistic optical properties and convincingly recapitulated fluorescence angiography scenes.

CONCLUSIONS

Methods identified in this study can facilitate the development of realistic phantoms as powerful new tools for fluorescence imaging.

Optimal Cost-Effective Screening Strategy for Unruptured Intracranial Aneurysms in Female Smokers

BACKGROUND

The prevalence of intracranial aneurysms among female cigarette smokers was shown to be high in previous studies, yet the cost-effectiveness of screening them has never been explored.

OBJECTIVE

To explore the most cost-effective screening strategy for female smokers.

METHODS

A decision analytical study was performed with a Markov model to compare different screening strategies with no screening and to explore the most optimal screening strategy for female smokers. Input data for the model were extracted from literature. A single screening at different ages and multiple screening every 15 years, 10 years, 5 years, and 2 years were performed for female smokers in different age ranges. Deterministic and probabilistic sensitivity analyses were performed to evaluate the robustness of the model. Finally, value of information analysis was performed to investigate the value of collecting additional data.

RESULTS

Screening female smokers for unruptured intracranial aneurysm is cost-effective. All screening strategies yield extra quality-adjusted life years. Screening at younger age brings more health benefit at lower cost. Frequent screening strategies decrease rupture rate of aneurysms more with higher costs per quality-adjusted life year. Screening after age 70 years and frequent screening (every 2 years) after age 60 years is not optimal. Among all the parameters in the model, collecting additional data on utility of the unscreened population would be most valuable.

CONCLUSION

Screening female smokers for intracranial aneurysms once at younger age is most optimal. However, in clinical practice, the duration and intensity of exposure to cigarettes should be taken into consideration.

A review of technological innovations leading to modern endovascular brain aneurysm treatment

Tools and techniques utilized in endovascular brain aneurysm treatment have undergone rapid evolution in recent decades. These technique and device-level innovations have allowed for treatment of highly complex intracranial aneurysms and improved patient outcomes. We review the major innovations within neurointervention that have led to the current state of brain aneurysm treatment.

Cost-effectiveness analysis on small (< 5 mm) unruptured intracranial aneurysm follow-up strategies

OBJECTIVE

Unruptured intracranial aneurysms are frequently detected during routine clinical diagnostic processes. A significant portion are small aneurysms less than 5 mm in diameter. While follow-up of patients with small aneurysms has been advocated, the cost-effectiveness of such care and the optimal follow-up interval remain unknown. This study aimed to explore the most cost-effective follow-up interval for small (< 5 mm) unruptured intracranial aneurysms.

METHODS

A decision analysis study was performed using a Markov model with Monte Carlo simulations to simulate patients undergoing follow-up by MRA at different time intervals (1-, 2-, 3-, 5-, and 7-year intervals) for small (< 5 mm) unruptured intracranial aneurysms. Input data for the model were extracted from the current literature, primarily meta-analyses. Probabilistic and deterministic sensitivity analyses were performed to evaluate the robustness of the model.

RESULTS

Given the current literature and the model in this study, following up every 2 years with noninvasive imaging is the most cost-effective strategy (cost $126,996, effectiveness 21.9 quality-adjusted life-years), showing the highest net monetary benefit. The conclusion remains robust in probabilistic and deterministic sensitivity analyses. As the annual growth risk of small aneurysms and annual rupture risk of growing aneurysms increase, following up every year is optimal. When the cost for follow-up with MRA is less than $2223, following up every year is cost-effective.

CONCLUSIONS

The most cost-effective follow-up strategy for small (< 5 mm) unruptured aneurysms using MRA is following up every 2 years. More frequent follow-up strategies or prompt preventive treatment would be more appropriate in patients with higher risk factors for growth and aneurysm rupture.

Microsurgery for intracranial aneurysms: A qualitative survey on technical challenges and technological solutions

Introduction

Microsurgery for the clipping of intracranial aneurysms remains a technically challenging and high-risk area of neurosurgery. We aimed to describe the technical challenges of aneurysm surgery, and the scope for technological innovations to overcome these barriers from the perspective of practising neurovascular surgeons.

Materials and Methods

Consultant neurovascular surgeons and members of the British Neurovascular Group (BNVG) were electronically invited to participate in an online survey regarding surgery for both ruptured and unruptured aneurysms. The free text survey asked three questions: what do they consider to be the principal technical barriers to aneurysm clipping? What technological advances have previously contributed to improving the safety and efficacy of aneurysm clipping? What technological advances do they anticipate improving the safety and efficacy of aneurysm clipping in the future? A qualitative synthesis of responses was performed using multi-rater emergent thematic analysis.

Results

The most significant reported historical advances in aneurysm surgery fell into five themes: (1) optimising clip placement, (2) minimising brain retraction, (3) tissue handling, (4) visualisation and orientation, and (5) management of intraoperative rupture. The most frequently reported innovation by far was indocyanine green angiography (84% of respondents). The three most commonly cited future advances were hybrid surgical and endovascular techniques, advances in intraoperative imaging, and patient-specific simulation and planning.

Conclusions

While some surgeons perceive that the rate of innovation in aneurysm clipping has been dwarfed in recent years by endovascular techniques, surgeons surveyed highlighted a broad range of future technologies that have the potential to continue to improve the safety of aneurysm surgery in the future.

Imaging Intracranial Aneurysms in the Endovascular Era: Surveillance and Posttreatment Follow-up

While most intracranial aneurysms (IAs) remain asymptomatic over a patient's lifetime, those that rupture can cause devastating outcomes. The increased usage and quality of neuroimaging has increased detection of unruptured IAs and driven an increase in surveillance and treatment of these lesions. Standard practice is to treat incidentally discovered unruptured IAs that confer high rupture risk as well as ruptured IAs to prevent rehemorrhage. IAs are increasingly treated with coil embolization instead of microsurgical clipping; more recently, flow diversion and intrasaccular flow disruption have further expanded the versatility and utility of endovascular IA treatment. Imaging is increasingly used for posttreatment IA follow-up in the endovascular era. While cerebral angiography remains the standard for IA characterization and treatment planning, advances in CT and CT angiography and MR angiography have improved the diagnostic accuracy of noninvasive imaging for initial diagnosis and surveillance. IA features including size, dome-to-neck ratio, location, and orientation allow rupture risk stratification and determination of optimal treatment strategy and timing. The radiologist should be familiar with the imaging appearance of common IA treatment devices and the expected imaging findings following treatment. In distinction to clipping and coil embolization, flow diversion and intrasaccular flow disruption induce progressive aneurysm obliteration over months to years. Careful assessment of the device; the treated IA; adjacent brain, bone, meninges; and involved extracranial and intracranial vasculature is crucial at posttreatment follow-up imaging to confirm aneurysm obliteration and identify short-term and long-term posttreatment complications. An invited commentary by Chatterjee is available online. Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. ^©RSNA, 2022.

Beyond Classic Anastomoses Training Models: Overview of Aneurysm Creation in Rodent Vessel Model

Nowadays, due to the decline in the number of microsurgical clippings for cerebral aneurysms and revascularization procedures, young neurosurgeons have fewer opportunities to participate and train on this type of surgery. Vascular neurosurgery is a demanding subspecialty that requires skills that can only be acquired with technical experience. This background pushes the new generations to be ready for such challenging cases by training hard on different available models, such as synthetic tubes, chicken wings, or placenta vessels. Although many training models for vascular neurosurgery have been described worldwide, one of the best is the rodent vessels model. It offers pulsation, coagulation, and real blood flow conditions in a physiologic atmosphere that mimics perfectly the intracranial human vessels environment, especially in terms of size. However, the current differences in governmental different regulations about the use of living animals in medical experimentation and the social awareness, as well as the lack of financial support, cause more difficulties for neurosurgeons to start with that kind of training. In this review, we describe the tools and techniques as basic steps for vascular microsurgery training by using rodent models, that provide an accurate copy of brain vessels environment under stable conditions. The initial three classical known microanastomoses for neurosurgeons are end-to-end, end-to-side, and side-to-side, but in literature, there have been described other more complex exercises for training and investigation, such as aneurysm models. Although there is still little data available, we aim to summarize and discuss aneurysm's training models and reviewed the current literature on the subject and its applications, including a detailed description of the techniques.

Evolution of the patient-first approach: a dual-trained, single-neurosurgeon experience with 2002 consecutive intracranial aneurysm treatments

OBJECTIVE

The paradigm for intracranial aneurysm (IA) treatment is shifting toward a hybrid approach involving open and endovascular techniques. The authors chronicled the evolution of IA treatment by retrospectively examining a large series of IA cases treated by a single dual-trained neurosurgeon, focusing on evolving technology relative to the choice of treatment options, perioperative morbidity, and mortality.

METHODS

The aneurysm database at the authors' institution was searched to identify consecutive patients treated with endovascular or open microsurgical approaches by one neurosurgeon during an 18-year time span. Patients were included regardless of IA rupture status, location or morphology, or treatment modality. Data collected were baseline clinical characteristics, aneurysm size, treatment modality, operative complications, in-hospital mortality, and retreatment rate.

RESULTS

A total of 1858 patients with 2002 IA treatments were included in the study. Three-hundred fifty IAs (17.5%) were ruptured. Open microsurgery was performed in 504 aneurysms (25.2%) and endovascular surgery in 1498 (74.8%). Endovascular IA treatments trended toward a growing use of flow diversion during the last 11 years. In-hospital mortality was 1.7% overall, including 7.0% in ruptured and 0.5% in unruptured cases. The overall complication rate was 3.3%, including 3.4% for microsurgical cases and 3.3% for endovascular cases. The rate of retreatment was 3.6% after clipping and 10.7% for endovascular treatment.

CONCLUSIONS

This study demonstrates complementary use of open and endovascular approaches for IA treatment. By customizing treatment to the patient, comparable rates of procedural complications, mortality, and retreatment were achieved for both endovascular and microsurgical approaches.

Intracranial-Intracranial Bypass for Aneurysms: Quantitative Intraoperative Assessment of Flow Preservation

BACKGROUND

Intraoperative flow measurement has proven utility in extracranial-intracranial bypass, particularly in assessing the adequacy of donors by measurement of cut flow. The nature of intracranial-intracranial (IC-IC) bypass precludes cut flow measurement, but quantitative intraoperative flow measurements may evaluate augment assessment of the bypass.

OBJECTIVE

To retrospectively evaluate flow measurements performed in IC-IC bypass to determine the adequacy of the constructs in preserving flow.

METHODS

With institutional review board approval, we performed a retrospective review of our bypass database from 2001 to 2021 for aneurysms treated with IC-IC bypass and with intraoperative flow measurements. Patients' preoperative characteristics, bypass indications, prebypass and postbypass intraoperative flow measurements, and patient outcomes were recorded.

RESULTS

Of 346 bypasses, 21 cases using 22 IC-IC bypasses were included. The median age was 55 years; 13 of 21 cases were ruptured aneurysms. Aneurysms involved posterior inferior cerebellar artery (n = 7), middle cerebral artery (n = 6), distal anterior cerebral artery (n = 5), and anterior communicating artery (n = 3). Six bypasses were end-to-side (ETS), 10 were side-to-side (STS), and 6 were excisional with reanastomosis (end-to-end, ETE). Intraoperatively, 21 of the bypasses were patent; the postbypass/prebypass flow index averaged 1.15 (±0.32): ETE (n = 6) 1.22 ± 0.34 and ETS/STS bypasses (n = 15) 1.11 ± 0.32. All intraoperatively patent bypasses were patent on postoperative angiography. One occluded on delayed angiography without clinical sequelae.

CONCLUSION

Despite advances in endovascular therapy, IC-IC bypass remains essential to the treatment of large and fusiform aneurysms. We demonstrate quantitatively that IC-IC donors provide adequate direct (ETE) and redistributed (STS ETS) flow to the recipient territory. Flow measurement provides valuable information regarding the patency and adequacy of IC-IC bypass for flow preservation.

Treatment of ruptured intracranial aneurysms with the Woven EndoBridge device: a systematic review

The Woven EndoBridge (WEB) device is a barrel-shaped nitinol mesh deployed within the aneurysmal sac. The absence of metallic mesh in the aneurysm's parent vessel lumen obviates the need for potent antiplatelet therapy, making this device appealing for acutely ruptured aneurysms not amenable to clipping or coiling. To assess the literature regarding WEB treatment of these aneurysms, we performed a comprehensive systematic search of PubMed, MEDLINE, and EMBASE databases following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Keywords were combined with Boolean operators to increase search sensitivity and specificity ('woven endobridge device' AND 'ruptured'). Nine studies comprising 377 acutely ruptured aneurysms were included. Overall, 82.7% were wide-necked, 85.9% were located in the anterior circulation, and 26.9% of patients presented with poor subarachnoid hemorrhage grade. Intraprocedure and postprocedure complications occurred in 8.4% (95% CI 3.6% to 13.3%) and 1% (95% CI 0% to 2%), respectively. The post-treatment rebleeding rate was 0%. Rates of adequate occlusion (complete occlusion to neck remnant) and retreatment at last follow-up were 84.8% (95% CI 73% to 96.6%) and 4.5% (95% CI 2.2% to 6.8%), respectively. The favorable outcome rate (modified Rankin Scale score 0-2) was 62.2% (95% CI 53% to 71.4%); mortality was 13.6% (95% CI 9.7% to 17.6%). WEB treatment of acutely ruptured aneurysms results in high adequate occlusion rates, low perioperative complication rates, no rebleeding, and low recurrence requiring retreatment. This device is promising for acutely ruptured aneurysms not amenable to clipping or coiling, considering the lower need for antiplatelet regimens during the procedure or follow-up.

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.