Clinical Risk Factors Affecting Procedure-Related Major Neurological Complications in Unruptured Intracranial Aneurysms

Risk Factors, Antithrombotic Management, and Long-Term Outcomes of Patients Undergoing Endovascular Treatment of Unruptured Intracranial Aneurysms

BACKGROUND

 Patients receiving endovascular treatment for unruptured intracranial aneurysms (UIAs) face varying risks and benefits with antithrombotic management. This study aimed to evaluate the perioperative and long-term effects of antithrombotic strategies, identify the populations that would benefit, and explore the predictive factors affecting the long-term outcomes.

METHODS

 UIA patients undergoing endovascular treatment including stent-assisted coiling or flow diversion between June 2019 and June 2022 were enrolled. We compared perioperative and long-term complications between tirofiban and dual antiplatelet therapy groups. Optimal candidates for each antithrombotic treatment were identified using multivariate logistic regression. Nomograms were developed to determine the significant predictors for thromboembolic complications during follow-up.

RESULTS

 Among 181 propensity-score matched pairs, the tirofiban group showed a trend toward a lower rate of thromboembolic complications than the DAPT group without elevating major bleeding risk in either period. Homocysteine (Hcy) level ≥10 μmol/L was a significant independent factor associated with thromboembolic complication in both periods. Subgroup analysis highlighted that in patients with high Hcy levels, tirofiban and sustained antiplatelet treatment for ≥12 months were protective factors, while a history of stroke was an independent risk factor for thromboembolic events in follow-up. Four variables were selected to construct a prognostic nomogram, history of hypertension, prior stroke, Hcy level, and the duration of antiplatelet therapy.

CONCLUSION

 Perioperative low-dose tirofiban and extended antiplatelet therapy demonstrated a favorable trend in long-term outcomes for UIA patients with preoperative Hcy levels ≥10 μmol/L undergoing endovascular treatment. The prognostic model offers reliable risk prediction and guides antithrombotic strategy decisions.

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.

Periprocedural cerebrovascular complications and 30-day outcomes of endovascular treatment for intracranial vertebral artery dissecting aneurysms

OBJECTIVE

The authors undertook an evaluation of periprocedural cerebrovascular complications and 30-day outcomes of endovascular treatment for intracranial vertebral artery dissecting aneurysms (IVADAs) and assessed the relevant risk factors.

METHODS

The authors included a series of 195 patients who had undergone endovascular treatment for 198 IVADAs. Clinical data, morphological characteristics, treatment details, and periprocedural cerebrovascular complications including intraprocedural rupture, intraprocedural thrombosis, intracranial hemorrhage (ICH), transient ischemic attack (TIA), and ischemic stroke (IS) were recorded. After evaluation of the 30-day modified Rankin Scale (mRS) scores, the authors applied univariate and multivariate logistic regression analyses to identify the risk factors for complications and 30-day unfavorable clinical outcomes.

RESULTS

There were no intraprocedural ruptures, but the authors recorded intraprocedural thrombosis (n = 5), ICH (n = 3), TIA (n = 1), and IS (n = 13), comprising an 11.1% (22/198) complication rate. Multivariate logistic regression analysis indicated that hyperlipidemia (odds ratio [OR] 3.17, 95% confidence interval [CI] 1.20-8.41, p = 0.020), IS history (OR 5.55, 95% CI 1.46-21.01, p = 0.012), and subarachnoid hemorrhage (SAH) (OR 4.48, 95% CI 1.52-13.20, p = 0.007) were risk factors for overall complications, whereas aneurysmal height (OR 0.77, 95% CI 0.61-0.98, p = 0.032) was a protective factor. SAH (OR 6.44, 95% CI 1.54-26.89, p = 0.011) and preprocedural mRS score > 2 (OR 5.07, 95% CI 1.01-25.59, p = 0.049) were independent risk factors for perforator occlusion stroke. Periprocedural cerebrovascular complications (OR 32.09, 95% CI 3.00-343.94, p = 0.004) and preprocedural mRS score > 2 (OR 319.92, 95% CI 30.28-3379.98, p < 0.001) were independent risk factors for 30-day unfavorable clinical outcomes.

CONCLUSIONS

Hyperlipidemia, IS history, and SAH were independent predictors for overall periprocedural cerebrovascular complications of endovascular treatment for IVADAs, but aneurysmal height was an independent protective factor. SAH and preprocedural mRS score > 2 were independent risk factors for perforator occlusion stroke. Preprocedural mRS score > 2 and periprocedural complications were independent risk factors for 30-day unfavorable clinical outcomes.

Clipping versus coiling in unruptured anterior cerebral circulation aneurysms

Background:

Unruptured intracranial aneurysms (UIAs) are not uncommon, especially in Japan. Treatment strategy for UIAs has evolved in the past decades in Western countries with the increased use of endovascular treatment as the primary option, but in Japan, clipping still has the upper hand.

Methods:

This study retrospectively included 200 patients treated by clipping or coiling for UIAs located in the anterior cerebral circulation. Postoperative angiographic and clinical outcomes were evaluated.

Results:

Of 200 UIAs, 147 and 53 were treated by surgery and coiling, respectively. The average follow-up duration was 30.2 ± 18.8 months for clipping and 29.3 ± 17.6 months for coiling. Complete occlusion was greater in the surgery group (78.9%) than the endovascular group (18.8%). Regrowth occurred in 1.4% of the clipping group and 13.2% of the coiling group. Ischemic events were encountered in both groups; asymptomatic ones were higher in the coiling group (24.5%) than in the clipping group (2%), while symptomatic ischemic complications were equal (7.5%) in both groups. The deterioration of modified Rankin scale was detected totally in 13 UIAs (6.5%) with no statistical difference between groups. Postoperative hospital period was longer in clipping (P = 0.01).

Conclusion:

Clipping and coiling were both safe and feasible in the treatment of unruptured aneurysms. The clipping was advantageous in durability, while the rate of morbidity was lower, and hospitalization period was shorter in the coiling group. The clipping and coiling should coexist while complementing each other by understanding the advantages and disadvantages of both.

Endovascular coiling versus surgical clipping for the treatment of unruptured cerebral aneurysms: Direct comparison of procedure-related complications

BACKGROUND

Endovascular coiling and surgical clipping are routinely used to treat unruptured cerebral aneurysms (UCAs). However, the evidence to support the efficacy of these approaches is limited. We aimed to analyze the efficacy of endovascular coiling compared with surgical clipping in patients with UCAs.

METHOD

A systematic search of 4 databases was conducted to identify comparative articles involving endovascular coiling and surgical clipping in patients with UCAs. We conducted a meta-analysis using the random-effects model when I> 50%. Otherwise, a meta-analysis using the fixed-effects model was performed.

RESULTS

Our results showed that endovascular coiling was associated with a shorter length of stay (WMD: -4.14, 95% CI: (-5.75, -2.531), P < .001) and a lower incidence of short-term complications compared with surgical clipping (OR: 0.518; 95% CI (0.433, 0.621); P < .001), which seems to be a result of ischemia complications (OR: 0.423; 95% CI (0.317, 0.564); P < .001). However, surgical clipping showed a higher rate of complete occlusion after surgery, in both short-term (OR: 0.179, 95% CI (0.064, 0.499), P = .001) and 1-year follow-ups (OR: 0.307, 95% CI (0.146, 0.646), P = .002), and a lower rate of short-term retreatment (OR: 0.307, 95% CI (0.146, 0.646), P = .002). Meanwhile, there was no significant difference in postoperative death, bleeding, and modified Rankin Scale (mRS) > 2 between the 2 groups.

CONCLUSIONS

The latest evidence illustrates that surgical clipping resulted in lower retreatment rates and was associated with a higher incidence of complete occlusion, while endovascular coiling was associated with shorter LOS and a lower rate of complications, especially ischemia.

Clipping versus coiling in posterior circulation intracranial aneurysms: a meta-analysis

Background

Posterior circulation intracranial aneurysm (IA) treatment remains challenging, due to the anatomy of the area and the high rupture possibility. Endovascular treatment seems to be more suitable for these aneurysms, but studies focused on endovascular treatment demonstrate a high rate of re-intervention needing. A meta-analysis might offer a clearer view, being useful in a more effective treatment planning.

Methods

A systematic search was performed, using the PubMed database platform. The final article pool contained 20 articles. Studied parameters were operative mortality, late mortality, permanent neurologic deficit (PND), and the need for re-intervention (Re-int). We divided patients into two subgroups, those with ruptured and those with unruptured aneurysm. Statistical analysis was performed using appropriate software.

Results

In the total population (645 patients), there was a superiority of coiling over clipping in terms of PND and of coiling in terms of Re-int. As regards mortality, there was no clear superiority of one method over the other.

Conclusions

The current study came to the conclusion that there is a superiority of coiling over clipping in terms of PND. On the other hand, clipping seems to be superior to coiling in terms of the need for re-intervention. As regards mortality (both operative and late), there is no clear superiority of one method over the other. Studying subgroups of patients (ruptured and unruptured posterior circulation IAs), in terms of PND, there is no superiority of one method over the other. The same goes for Op-Mo on ruptured aneurysms.

Procedural Clinical Complications, Case-Fatality Risks, and Risk Factors in Endovascular and Neurosurgical Treatment of Unruptured Intracranial Aneurysms: A Systematic Review and Meta-analysis

Importance

The risk of procedural clinical complications and the case-fatality rate (CFR) from preventive treatment of unruptured intracranial aneurysms varies between studies and may depend on treatment modality and risk factors.

Objective

To assess current procedural clinical 30-day complications and the CFR from endovascular treatment (EVT) and neurosurgical treatment (NST) of unruptured intracranial aneurysms and risk factors of clinical complications.

Data Sources

We searched PubMed, Excerpta Medica Database, and the Cochrane Database for studies published between January 1, 2011, and January 1, 2017.

Study Selection

Studies reporting on clinical complications, the CFR, and risk factors, including 50 patients or more undergoing EVT or NST for saccular unruptured intracranial aneurysms after January 1, 2000, were eligible.

Data Extraction and Synthesis

Per treatment modality, we analyzed clinical complication risk and the CFR with mixed-effects logistic regression models for dichotomous data. For studies reporting data on complication risk factors, we obtained risk ratios (RRs) or odds ratios (ORs) with 95% CIs and pooled risk estimates with weighted random-effects models.

Main Outcomes and Measures

Clinical complications within 30 days and the CFR.

Results

We included 114 studies (106 433 patients with 108 263 aneurysms). For EVT (74 studies), the pooled clinical complication risk was 4.96% (95% CI, 4.00%-6.12%), and the CFR was 0.30% (95% CI, 0.20%-0.40%). Factors associated with complications from EVT were female sex (pooled OR, 1.06 [95% CI, 1.01-1.11]), diabetes (OR, 1.81 [95% CI, 1.05-3.13]), hyperlipidemia (OR, 1.76 [95% CI, 1.3-2.37]), cardiac comorbidity (OR, 2.27 [95% CI, 1.53-3.37]), wide aneurysm neck (>4 mm or dome-to-neck ratio >1.5; OR, 1.71 [95% CI, 1.38-2.11]), posterior circulation aneurysm (OR, 1.42 [95% CI, 1.15-1.74]), stent-assisted coiling (OR, 1.82 [95% CI, 1.16-2.85]), and stenting (OR, 3.43 [95% CI, 1.45-8.09]). For NST (54 studies), the pooled complication risk was 8.34% (95% CI, 6.25%-11.10%) and the CFR was 0.10% (95% CI, 0.00%-0.20%). Factors associated with complications from NST were age (OR per year increase, 1.02 [95% CI, 1.01-1.02]), female sex (OR, 0.43 [95% CI, 0.32-0.85]), coagulopathy (OR, 2.14 [95% CI, 1.13-4.06]), use of anticoagulation (OR, 6.36 [95% CI, 2.55-15.85]), smoking (OR, 1.95 [95% CI, 1.36-2.79]), hypertension (OR, 1.45 [95% CI, 1.03-2.03]), diabetes (OR, 2.38 [95% CI, 1.54-3.67]), congestive heart failure (OR, 2.71 [95% CI, 1.57-4.69]), posterior aneurysm location (OR, 7.25 [95% CI, 3.70-14.20]), and aneurysm calcification (OR, 2.89 [95% CI, 1.35-6.18]).

Conclusions and Relevance

This study identifies risk factors for procedural complications. Large data sets with individual patient data are needed to develop and validate prediction scores for absolute complication risks and CFRs from EVT and NST modalities.

Meta-Analysis of Clipping versus Coiling for the Treatment of Unruptured Middle Cerebral Artery Aneurysms: Direct Comparison of Procedure-Related Complications

BACKGROUND

Endovascular coiling and surgical clipping are routinely used to treat unruptured middle cerebral artery aneurysms (MCAAs). However, the optimal treatment for unruptured MCAAs is controversial. We aimed to systematically and comprehensively compare the clinical outcomes between endovascular coiling and surgical clipping for the treatment of MCAAs.

METHOD

This meta-analysis retrieved academic articles comparing the clinical outcomes between endovascular coiling and surgical clipping for unruptured MCAAs from the Cochrane Library, Medline, PubMed, and EMBASE databases. The reference articles of the identified studies were carefully reviewed to ensure that all available articles were represented in the study. The meta-analysis was conducted in accordance with the acknowledged the prioritized reported items for systematic review and meta-analysis (PRISMA) guidelines.

RESULTS

A total of 6 studies, which enrolled a total of 789 participants, were included in our analysis. Of these 789 patients with MCAAs, 144 were assigned to an endovascular coiling group, and 645 were assigned to a surgical clipping group. Our results demonstrated that endovascular coiling was associated with a higher rate of retreatment (OR = 104.926; 95% CI: 12.931 to 851.379; P<0.001) and postoperative complications (OR = 3.157; 95% CI: 1.239 to 8.048; P= 0.016) than surgical clipping, especially for postoperative thrombus without infarction (OR = 4.905, 95% CI: 1.097 to 21.933; P = 0.037). Furthermore, surgical clipping was related to a higher rate of complete occlusion (OR = 0.349, 95% CI: 0.140 to 0.872; P = 0.024) and Glasgow Outcome Scale (GOS) ≥4 (OR = 0.250; 95% CI: 0.072 to 0.867; P= 0.029) than endovascular coiling after the operation. However, there was no significant difference in the rate of death, the proportion of patients with modified Rankin Scale (mRS)>2, infarction, or bleeding.

CONCLUSION

Although this study has inherent limitations, surgical clipping of unruptured MCAAs resulted in significantly higher complete aneurysm occlusion and GOS≥4 rates and was associated with a lower incidence of retreatment and complication, especially for postoperative thrombus without infarction. Therefore, the effect induced by surgical clipping of unruptured MCAAs remains superior to that induced by endovascular coiling; surgical clipping should be regarded as the first choice of treatment for unruptured MCAAs.

Unruptured aneurysms in the elderly: perioperative outcomes and cost analysis of endovascular coiling and surgical clipping

OBJECTIVE

Observation and neurosurgical intervention for unruptured intracranial aneurysms (UIAs) in the elderly population is rapidly increasing. Cerebral aneurysm coiling (CACo) is favored over cerebral aneurysm clipping (CAC) in elderly patients, yet some elderly individuals still undergo CAC. The cost-effectiveness of treating UIAs requires further exploration. Understanding the effect of intervention on hospital charges and length of stay (LOS) as well as perioperative mortality and complications can further shed light on its economic impact. The purpose of this study was to analyze the cost and perioperative outcomes of UIAs in elderly patients (≥ 65 years of age) after CACo or CAC intervention.

METHODS

Retrospective cohorts of CACo and CAC admissions were extracted from National (Nationwide) Inpatient Sample data obtained between 2002 and 2013, forming parallel intervention groups to compare the following outcomes between elderly and nonelderly patients: average LOS and mean hospital admission costs, in-hospital mortality, and complications. Covariates included sex, race or ethnicity, and comorbidities.

RESULTS

Elderly patients undergoing CAC experienced an average LOS of 8.0 days, whereas elderly patients undergoing CACo stayed an average of 3.2 days. The mean hospital charges incurred during admission totaled $95,960 in the elderly patients who underwent CAC versus $87,960 in the ones who underwent CACo. Elderly patients in whom CAC was performed had a 2.2% rate of in-hospital mortality, with a 2.6 greater adjusted odds of in-hospital mortality than nonelderly patients treated with CAC. In contrast, elderly patients who underwent CACo had a 1.36 greater adjusted odds of in-hospital mortality than their nonelderly counterparts. Compared to nonelderly patients receiving both interventions, elderly individuals had a significantly higher prevalence of various comorbidities and incidence of complications. Elderly patients who received CAC experienced a 10.3% incidence rate of perioperative stroke, whereas their CACo counterparts experienced this complication at a rate of 3.5%. Elderly patients treated with CAC had greater odds of perioperative acute renal failure, whereas their CACo counterparts had greater odds of perioperative deep venous thrombosis and pulmonary embolism.

CONCLUSIONS

Intervention with CAC and CACo in the elderly is resource intensive and is associated with higher risk than in the nonelderly. Those deciding between intervention and conservative management should consider these risks and costs, especially the 2.2% postoperative mortality rate associated with CAC in the elderly population. Further comparative cost-effectiveness research is needed to weigh these costs and outcomes against those of conservative management.

Coiling Versus Microsurgical Clipping in the Treatment of Unruptured Middle Cerebral Artery Aneurysms: A Meta-Analysis

BACKGROUND

Open microsurgical clipping of unruptured intracranial aneurysms has long been the gold standard, yet advancements in endovascular coiling techniques have begun to challenge the status quo.

OBJECTIVE

To compare endovascular coiling with microsurgical clipping among adults with unruptured middle cerebral artery aneurysms (MCAA) by conducting a meta-analysis.

METHODS

A systematic search was conducted from January 2011 to October 2015 to update a previous meta-analysis. All studies that reported unruptured MCAA in adults treated by microsurgical clipping or endovascular coiling were included and cumulatively analyzed.

RESULTS

Thirty-seven studies including 3352 patients were included. Using the random-effects model, pooled analysis of 11 studies of microsurgical clipping (626 aneurysms) revealed complete aneurysmal obliteration in 94.2% of cases (95% confidence interval [CI] 87.6%-97.4%). The analysis of 18 studies of endovascular coiling (759 aneurysms) revealed complete obliteration in 53.2% of cases (95% CI: 45.0%-61.1%). Among clipping studies, 22 assessed neurological outcomes (2404 aneurysms), with favorable outcomes in 97.9% (95% CI: 96.8%-98.6%). Among coiling studies, 22 examined neurological outcomes (826 aneurysms), with favorable outcomes in 95.1% (95% CI: 93.1%-96.5%). Results using the fixed-effect models were not materially different.

CONCLUSION

This updated meta-analysis demonstrates that surgical clipping for unruptured MCAA remains highly safe and efficacious. Endovascular treatment for unruptured MCAAs continues to improve in efficacy and safety; yet, it results in lower rates of occlusion.

The efficacy of microsurgery in the treatment of cerebral aneurysm rupture and its effect on NF-κB, MCP-1 and MMP-9

The clinical efficacy of microsurgical neck clipping for the treatment of cerebral aneurysm rupture and its effect on serum nuclear factor κ-light-chain-enhancer of activated β cells (NF-κB), monocyte chemoattractant protein-1 (MCP-1) and matrix metalloproteinase-9 (MMP-9) levels were investigated. A total of 56 patients with first occurrence of cerebral aneurysm rupture were enrolled from June 2015 to June 2016. These patients were divided into control (25 patients) and observation groups (31 patients) according to treatment received. The patients in the control group were treated with interventional embolization and extraventricular drainage, while the patients in the observation group were treated with microsurgical neck clipping. Serum NF-κB, MCP-1 and MMP-9 levels were measured by ELISA prior to the operation and at 6 h post-operation. Clinical effects were compared at the 6-month follow-up. There was no significant difference in the success rate of the operation between the two groups (p>0.05). The incidence of complications in the observation group was significantly lower than that in the control group (p<0.05). The Glasgow Outcome Scale score was significantly improved in the observation group (p<0.05) compared with the control group. Serum NF-κB, MMP-9 and MCP-1 were significantly decreased in both groups at 6 and 24 h after operation, but the observational group showed significantly lower levels for all three proteins than the control group (p<0.05). The application of early microsurgical neck clipping for the treatment of cerebral aneurysm rupture can reduce complications and improve clinical prognosis, and this may be related to a decrease in serum inflammatory response-related factors (NF-κB and MCP-1) and MMP-9.

Risk Factors to Predict Neurologic Complications After Endovascular Treatment of Unruptured Paraclinoid Aneurysms

OBJECTIVE

Unruptured paraclinoid aneurysms are often asymptomatic, and endovascular coiling is the main treatment. However, endovascular treatment of these lesions still leads to neurologic complications. We aimed to identify predictors of neurologic complications in these lesions.

METHODS

We retrospectively analyzed patients with unruptured paraclinoid aneurysms who were treated with endovascular coiling between January 2014 and December 2015. A neurologic complication was defined as any transient or permanent increase in the modified Rankin Scale score after aneurysm embolization. Univariate and mulitivariate logistic regression analyses were performed to assess the risk factors of neurologic complications.

RESULTS

Of the 443 unruptured paraclinoid aneurysms that were included in this study, the incidence of neurologic complications was 5.2%. Neurologic complications were highly correlated with hypertension (odds ratio [OR], 3.147; 95% confidence interval [CI], 1.217-8.138; P = 0.018), cerebral ischemic comorbidities (OR, 3.396; 95% CI, 1.378-8.374; P = 0.008), and aneurysm size (OR, 7.714; 95% CI, 1.784-31.635; P < 0.001), and irregular shape (OR, 3.157; 95% CI, 1.239-8.043; P = 0.016) in the univariate analysis. Cerebral ischemic comorbidities (OR, 2.837, 95% CI, 1.070-7.523; P = 0.036) and aneurysm size as dichotomous variables (OR, 7.557; 95% CI, 2.975-19.198; P < 0.001) were strongly correlated with neurologic complications in the final adjusted multivariate logistic analysis.

CONCLUSIONS

Unruptured paraclinoid aneurysms after endovascular treatments had 5.2% of neurologic complications. Cerebral ischemic comorbidities and aneurysm size were predictors of neurologic complications.

Microsurgery Simulator of Cerebral Aneurysm Clipping with Interactive Cerebral Deformation Featuring a Virtual Arachnoid

BACKGROUND

A virtual reality simulator for aneurysmal clipping surgery is an attractive research target for neurosurgeons. Brain deformation is one of the most important functionalities necessary for an accurate clipping simulator and is vastly affected by the status of the supporting tissue, such as the arachnoid membrane. However, no virtual reality simulator implementing the supporting tissue of the brain has yet been developed.

OBJECTIVE

To develop a virtual reality clipping simulator possessing interactive brain deforming capability closely dependent on arachnoid dissection and apply it to clinical cases.

METHODS

Three-dimensional computer graphics models of cerebral tissue and surrounding structures were extracted from medical images. We developed a new method for modifiable cerebral tissue complex deformation by incorporating a nonmedical image-derived virtual arachnoid/trabecula in a process called multitissue integrated interactive deformation (MTIID). MTIID made it possible for cerebral tissue complexes to selectively deform at the site of dissection. Simulations for 8 cases of actual clipping surgery were performed before surgery and evaluated for their usefulness in surgical approach planning.

RESULTS

Preoperatively, each operative field was precisely reproduced and visualized with the virtual brain retraction defined by users. The clear visualization of the optimal approach to treating the aneurysm via an appropriate arachnoid incision was possible with MTIID.

CONCLUSION

A virtual clipping simulator mainly focusing on supporting tissues and less on physical properties seemed to be useful in the surgical simulation of cerebral aneurysm clipping. To our knowledge, this article is the first to report brain deformation based on supporting tissues.

Quantitative analysis of the effect of institutional case volume on complications after surgical clipping of unruptured aneurysms

OBJECTIVE The mechanism by which greater institutional case volume translates into improved outcomes after surgical clipping of unruptured intracranial aneurysms (UIAs) is not well established. The authors thus aimed to assess the effect of case volume on the rate of various types of complications after clipping of UIAs. METHODS Using information on the outcomes of inpatient admissions for surgical clipping of UIAs collected within a national database, the relationship of institutional case volume to the incidence of different types of complications after clipping was investigated. Complications were subdivided into different categories, which included all complications, ischemic stroke, intracerebral hemorrhage, medical complications, infectious complications, complications related to anesthesia, and wound complications. The relationship of case volume to different types of complications was assessed using linear regression analysis. The relationships between case volume and overall complication and stroke rates were fit with both linear and quadratic equations. The numerical cutoff for institutional case volume above and below which the authors found the greatest differences in mean overall complication and stroke rate was determined using classification and regression tree (CART) analysis. RESULTS Between October 2012 and September 2015, 125 health care institutions reported patient outcomes from a total of 6040 cases of clipping of UIAs. On linear regression analysis, increasing case volume was negatively correlated to both overall complications (r² = 0.046, p = 0.0234) and stroke (r² = 0.029, p = 0.0557) rate, although the relationship of case volume to the complication (r² = 0.092) and stroke (r² = 0.067) rate was better fit with a quadratic equation. On CART analysis, the cutoff for the case number that yielded the greatest difference in overall complications and stroke rate between higher- or lower-volume centers was 6 cases/year and 3 cases/year, respectively. CONCLUSIONS Although the authors confirm that increasing case volume is associated with reduced complications after clipping of UIAs, their results suggest that the relationship between case volume and complications is not necessarily linear. Moreover, these results indicate that the effect of case volume on outcome is most evident between very-low-volume centers relative to centers with a medium-to-high volume.

[Progressive hematoma in anterior neck after endovascular treatment of middle cerebral artery aneurysm]

BACKGROUND

Cervical hematomas can lead to airway compromise, a life threatening condition, regardless of the cause. The following case is the first presentation of cervical hematoma as a complication of endovascular treatment of middle cerebral artery aneurysm.

CASE REPORT

A 49 year-old woman was scheduled for stent placement under general anesthesia for middle cerebral artery aneurysm. Few days before intervention, acetyl salicylic acid and clopidogrel treatment was started. Following standard monitoring and anesthesia induction, the patient's trachea was intubated with a 7.5mm endotracheal tube and the procedure was completed without any complications. Three hours later, dyspnea developed and physical examination revealed progressive swelling and stiffness in the neck. Endotracheal intubation was performed with a 6mm diameter uncuffed tube with the aid of sedation. The vocal cords were completely closed due to compression. There was no leak around the endotracheal tube. The rapidly performed computerized tomography scans showed an enormous hematoma around the neck and extravasation of contrast medium through superior thyroid artery. After coil embolization of superior thyroid artery, she was taken to the intensive care unit as intubated and sedated. Surgical exploration of the hematoma was not recommended by the surgeons, because she was on clopidogrel. After two days, the patient's trachea was extubated safely ensuring that the swelling was sufficiently ceased and leak detected around the endotracheal tube.

CONCLUSIONS

Securing the airway rapidly by endotracheal intubation is the most crucial point in the management of cervical hematomas. Diagnostic and therapeutic procedures should be performed only afterwards.

Risk Factors for the Rupture of Bifurcation Intracranial Aneurysms Using CT Angiography

PURPOSE

To investigate the clinical and morphological characteristics in relation to risk of bifurcation intracranial aneurysm rupture.

MATERIALS AND METHODS

Data from 202 consecutive patients with 219 bifurcation aneurysms (129 ruptured and 90 unruptured) managed at the authors' facility between August 2011 and July 2014 were retrospectively reviewed. Based on their clinical records and CT angiographic findings, the ability of risk factors to predict aneurysm rupture was assessed using statistical methods.

RESULTS

Age, hypertension, diabetes mellitus, and cerebral atherosclerosis were negatively correlated with aneurysm rupture. Aneurysms located in the middle cerebral artery, daughter artery ratio, lateral angle ratio (LA ratio), and neck width were negatively correlated with rupture. Aneurysms located in the anterior communicating artery, irregularity, with daughter sac, depth, width, maximum size, aspect ratio (AR), depth-to-width ratio, and bottleneck factor were significantly and positively correlated with rupture. Binary logistic regression model revealed that irregular shape [odds ratio (OR) 6.598] and AR (OR 3.507) strongly increased the risk of bifurcation aneurysm rupture, while age (OR 0.434), cerebral atherosclerosis (OR 0.125), neck width (OR 0.771), and LA ratio (OR 0.267) were negatively correlated with rupture (p<0.05). Receiver operating characteristic analysis revealed the threshold values of AR and LA ratio to be 1.18 and 1.50, respectively.

CONCLUSION

Age (≥60 yr), cerebral atherosclerosis, and aneurysms with a larger neck width and larger LA ratio are protective factors against bifurcation aneurysm rupture. An aneurysm with an irregular shape and an increased AR reflect the greater likelihood of a rupture.

Risk Score for Neurological Complications After Endovascular Treatment of Unruptured Intracranial Aneurysms

BACKGROUND AND PURPOSE

Procedure-related neurological complications are common after endovascular treatment of unruptured intracranial aneurysms. We aimed to develop a score to quantify individual patient risk.

METHODS

We retrospectively analyzed consecutive patients who underwent endovascular treatment for unruptured intracranial aneurysms between January 2012 and September 2015. After excluding those who lost to follow-up and those with fusiform unruptured intracranial aneurysms, included patients were randomly divided into a derivation group (60%) and a validation group (40%). A neurological complication was defined as any transient or permanent increase in the modified Rankin Scale score after aneurysm embolization. A risk score for neurological complications was derived from multivariable logistic regression analyses in the derivation group and validated in the validation group.

RESULTS

Overall, 1060 patients were included (636 in the derivation group and 424 in the validation group). The incidence of neurological complications was 5.5% (95% confidence interval, 3.8%-7.4%). A 3-point risk score (S-C-C) was derived to predict neurological complications (size [≥10 mm=1], core areas [yes=1], and cerebral ischemic comorbidity [yes=1]). The incidence of neurological complications varied from 2.2% in 0-point patients to 25.0% in 3-point patients. The score demonstrated significant discrimination (C-statistic, 0.714; 95% confidence interval, 0.624-0.804) and calibration (McFadden R(2), 0.102) in the derivation group. Excellent prediction, discrimination, and calibration properties were reproduced in the validation group.

CONCLUSIONS

One in 20 patients will develop neurological complications after endovascular treatment of unruptured intracranial aneurysms. The S-C-C score may be useful for predicting these adverse outcomes based on variables in daily practice.