Anatomic risk factors for middle cerebral artery aneurysm rupture: computed tomography angiography study of 1009 consecutive patients

Advances in artificial intelligence, robotics, augmented and virtual reality in neurosurgery

Neurosurgical practitioners undergo extensive and prolonged training to acquire diverse technical proficiencies, while neurosurgical procedures necessitate a substantial amount of pre-, post-, and intraoperative clinical data acquisition, making decisions, attention, and convalescence. The past decade witnessed an appreciable escalation in the significance of artificial intelligence (AI) in neurosurgery. AI holds significant potential in neurosurgery as it supplements the abilities of neurosurgeons to offer optimal interventional and non-interventional care to patients by improving prognostic and diagnostic outcomes in clinical therapy and assisting neurosurgeons in making decisions while surgical interventions to enhance patient outcomes. Other technologies including augmented reality, robotics, and virtual reality can assist and promote neurosurgical methods as well. Moreover, they play a significant role in generating, processing, as well as storing experimental and clinical data. Also, the usage of these technologies in neurosurgery is able to curtail the number of costs linked with surgical care and extend high-quality health care to a wider populace. This narrative review aims to integrate the results of articles that elucidate the role of the aforementioned technologies in neurosurgery.

Physiological Responses and Training Satisfaction During National Rollout of a Neurosurgical Intraoperative Catastrophe Simulator for Resident Training

BACKGROUND

Systematic use of neurosurgical training simulators across institutions is significantly hindered by logistical and financial constraints.

OBJECTIVE

To evaluate feasibility of large-scale implementation of an intraoperative catastrophe simulation, we introduced a highly portable and low-cost immersive neurosurgical simulator into a nationwide curriculum for neurosurgery residents, during years 2016 to 2019.

METHODS

The simulator was deployed at 9 Society of Neurological Surgeons junior resident courses and a Congress of Neurological Surgeons education course for a cohort of 526 residents. Heart rate was tracked to monitor physiological responses to simulated stress. Experiential survey data were collected to evaluate simulator fidelity and resident attitudes toward simulation.

RESULTS

Residents rated the simulator positively with a statistically significant increase in satisfaction over time accompanying refinements in the simulator model and clinical scenario. The simulated complications induced stress-related tachycardia in most participants (n = 249); however, a cohort of participants was identified that experienced significant bradycardia (n = 24) in response to simulated stress.

CONCLUSION

Incorporation of immersive neurosurgical simulation into the US national curriculum is logistically feasible and cost-effective for neurosurgical learners. Participant surveys and physiological data suggest that the simulation model recreates the situational physiological stress experienced during practice in the live clinical environment. Simulation may provide an opportunity to identify trainees with maladaptive responses to operative stress who could benefit from additional simulated exposure to mitigate stress impacts on performance.

Attitudes Toward Neurosurgery Education for the Nonneurosurgeon: A Survey Study and Critical Analysis of U.S. Military Training Techniques and Future Prospects

BACKGROUND

The U.S. military requires medical readiness to support forward-deployed combat operations. Because time and distance to neurosurgical capabilities vary within the deployed trauma system, nonneurosurgeons are required to perform emergent cranial procedures in select cases. It is unclear whether these surgeons have sufficient training in these procedures.

METHODS

This quality-improvement study involved a voluntary, anonymized specialty-specific survey of active-duty surgeons about their experience and attitudes toward U.S. military emergency neurosurgical training.

RESULTS

Survey responses were received from 104 general surgeons and 26 neurosurgeons. Among general surgeons, 81% have deployed and 53% received training in emergency neurosurgical procedures before deployment. Only 16% of general surgeons reported participating in craniotomy/craniectomy procedures in the last year. Nine general surgeons reported performing an emergency neurosurgical procedure while on deployment/humanitarian mission, and 87% of respondents expressed interest in further predeployment emergency neurosurgery training. Among neurosurgeons, 81% had participated in training nonneurosurgeons and 73% believe that more comprehensive training for nonneurosurgeons before deployment is needed. General surgeons proposed lower procedure minimums for competency for external ventricular drain placement and craniotomy/craniectomy than did neurosurgeons. Only 37% of general surgeons had used mixed/augmented reality in any capacity previously; for combat procedures, most (90%) would prefer using synchronous supervision via high-fidelity video teleconferencing over mixed reality.

CONCLUSIONS

These survey results show a gap in readiness for neurosurgical procedures for forward-deployed general surgeons. Capitalizing on capabilities such as mixed/augmented reality would be a force multiplier and a potential means of improving neurosurgical capabilities in the forward-deployed environments.

Nomogram model for predicting oculomotor nerve palsy in patients with intracranial aneurysm

AIM

To explore the risk factors of oculomotor nerve palsy (ONP) in patients with intracranial aneurysm (IA) and develop a nomogram model for predicting ONP of IA patients.

METHODS

A total of 329 IA patients were included. Logistic regression analysis was applied to identify independent factors, which were then integrated into the nomogram model. The performance of the nomogram model was evaluated by calibration curve, receiver operating curve (ROC), and decision curve analysis.

RESULTS

Univariate and multivariate logistic regression analysis indicated posterior communicating artery (PCoA) aneurysm [hazard ratio (HR)=17.13, P<0.001] and aneurysm diameter (HR=1.31, P<0.001) were independent risk factors of ONP in IA patients. Based on the results of logistic regression analysis, a nomogram model for predicting the ONP in IA patients was constructed. The calibration curve indicated the nomogram had a good agreement between the predictions and observations. The nomogram showed a high predictive accuracy and discriminative ability with an area under the curve (AUC) of 0.863. The decision curve analysis showed that the nomogram was powerful in the clinical decision. PCoA aneurysm (HR=3.38, P=0.015) was identified to be the only independent risk factor for ONP severity.

CONCLUSION

PCoA aneurysm and aneurysm diameter are independent risk factors of ONP in IA patients. The nomogram established is performed reliably and accurately for predicting ONP. PCoA aneurysm is the only independent risk factor for ONP severity.

Nonlinear Association of Glycosylated Hemoglobin With Single Intracranial Aneurysm Rupture in Patients With Diabetes Mellitus: A Cross-Sectional Study

Background

The published literature linking diabetes mellitus (DM) to intracranial aneurysm (IA) ruptured has been controversial and limited by methodology. Thus, this study was performed to examine whether hyperglycemia control status is independently associated with single IA rupture in patients with DM.

Methods

We conducted a cross-sectional study on two Chinese hospitals between January 2010 and November 2017. Medical records of 223 patients with single IA and DM were reviewed and analyzed. We used glycosylated hemoglobin (GHB) as the independent variable of interest, and the outcome variable was ruptured status of IA. Covariates included data on demographics, morphological parameters, lifestyle habits, clinical features, and comorbidities.

Results

Multivariable adjusted binary logistic regression and sensitivity analyses indicated that GHB was not associated with IA rupture (odds ratio OR, = 1.07, 95% CI 0.84-1.35). A nonlinear association between GHB and IA rupture was observed, whose inflection points were 5.5 and 8.9. The OR values (95% confidence intervals) were 0.38 (0.16-0.9) at the range of 1.88-5.5% of GHB, 1.6 (1.03, 2.5) at the range of 5.5-8.9%, and 0.56 (0.06-5.34) at the range of 8.9-10.1, respectively.

Conclusion

The independent correlation between GHB and risk of IA rupture presented is nonlinear. The good glycemic control in single IA patients with DM can reduce the risk of IA rupture, and vice versa.

Efficacy and safety of endovascular therapy versus surgical clipping for patients with unruptured middle cerebral artery bifurcation aneurysms

This study aims to evaluate the efficacy and safety of endovascular therapy versus neurosurgical clipping carried out for patients with unruptured middle cerebral artery bifurcation aneurysms (MCABAs). Patients diagnosed with MCABAs were enrolled in this prospective study according to the inclusion and exclusion standard. Enrolled patients were divided into a study group (endovascular therapy) and a control group (neurosurgical clipping), with 65 cases in each group. In terms of efficacy, we found that the proportion of Glasgow Outcome Scale (GOS) grade 1 after treatment in the study group was significantly higher than in the control group (p<0.001), while the proportion of GOS grades 2, 3, and 4 after treatment was significantly lower in the study group than in the control group (p<0.05). The postoperative brain injury indicators neuron-specific enolase and S100β in the study group were significantly lower than in the control group (p<0.001), and the postoperative life activity score of patients in the study group was significantly higher than in the control group (p<0.001). In terms of safety, the postoperative hospital stay of patients in the study group was significantly shorter than in the control group (p<0.001), and the incidence rate of postoperative pulmonary and intracranial infections in the study group was significantly lower than in the control group (p<0.05). Endovascular therapy for patients with unruptured MCABAs may be effective in improving outcomes and has better safety profile compared with neurosurgical clipping, but may increase the risk of postoperative recurrence.

Virtual Reality in Neurosurgery: Beyond Neurosurgical Planning

Background: While several publications have focused on the intuitive role of augmented reality (AR) and virtual reality (VR) in neurosurgical planning, the aim of this review was to explore other avenues, where these technologies have significant utility and applicability. Methods: This review was conducted by searching PubMed, PubMed Central, Google Scholar, the Scopus database, the Web of Science Core Collection database, and the SciELO citation index, from 1989–2021. An example of a search strategy used in PubMed Central is: “Virtual reality” [All Fields] AND (“neurosurgical procedures” [MeSH Terms] OR (“neurosurgical” [All Fields] AND “procedures” [All Fields]) OR “neurosurgical procedures” [All Fields] OR “neurosurgery” [All Fields] OR “neurosurgery” [MeSH Terms]). Using this search strategy, we identified 487 (PubMed), 1097 (PubMed Central), and 275 citations (Web of Science Core Collection database). Results: Articles were found and reviewed showing numerous applications of VR/AR in neurosurgery. These applications included their utility as a supplement and augment for neuronavigation in the fields of diagnosis for complex vascular interventions, spine deformity correction, resident training, procedural practice, pain management, and rehabilitation of neurosurgical patients. These technologies have also shown promise in other area of neurosurgery, such as consent taking, training of ancillary personnel, and improving patient comfort during procedures, as well as a tool for training neurosurgeons in other advancements in the field, such as robotic neurosurgery. Conclusions: We present the first review of the immense possibilities of VR in neurosurgery, beyond merely planning for surgical procedures. The importance of VR and AR, especially in “social distancing” in neurosurgery training, for economically disadvantaged sections, for prevention of medicolegal claims and in pain management and rehabilitation, is promising and warrants further research.

U-Shaped Association of Aspect Ratio and Single Intracranial Aneurysm Rupture in Chinese Patients: A Cross-Sectional Study

Background: Previous studies have analyzed the association of aspect ratio (AR) on the ruptured intracranial aneurysm (IA), but the findings are inconclusive and controversial. Therefore, the study aimed to derive a more detailed estimation of this association between AR and ruptured IA in Chinese IA patients. Methods: The present work was a cross-sectional study. We retrospectively collected 1,588 Chinese patients with a single IA from January 2010 to November 2017. The relationship was examined between AR at diagnosis and ruptured IA. Covariates included data of demographics, morphological parameters, lifestyle habits, clinical features, and comorbidities. Binary logistic regression and two-piecewise linear models were used to analyze independent associations of AR with ruptured IA. Results: The results suggest that the association between AR and IA rupture was U-shaped. In the AR range of 1.08-1.99, the prevalence of IA rupture was 13% lower for each 0.1-unit increment in AR [odds ratio 0.87, 95% confidence interval (CI) 0.80-0.98]. Conversely, for every 0.1-unit increase in AR, the prevalence of IA rupture increased by ~3% (odds ratio 1.03, 95% CI 1.01-1.06) in the AR range of 3.42-4.08. Conclusion: The relationship between AR and ruptured IA was U-shaped, with the negative association at AR of 1.08-1.99 and positive association at AR of 3.42-4.08.

Endoluminal flow diverting stents for middle cerebral artery bifurcation aneurysms: multicenter cohort

BACKGROUND

Data regarding the safety and efficacy of flow diverting stents (FDS) in the treatment of middle cerebral artery (MCA) bifurcation aneurysms are scarce and limited to small single center series, with particular concern for increased risk of ischemic complications with jailing one of the M2 branches.

METHODS

Prospectively-maintained databases at six North American and European centers were queried for patients harboring MCA bifurcation aneurysms undergoing treatment with FDS (2011-2018). The pertinent clinical and radiographic data were collected and analyzed.

RESULTS

87 patients (median age 60 years, 69% females) harboring 87 aneurysms were included. The majority of aneurysms were unruptured (79%); 75.9% were saccular with a median maximal diameter of 8.5 mm. Radiographic imaging follow-up was available in 88.5% of cases at a median of 16.3 months post-treatment, showing complete occlusion in 59% and near complete occlusion (90-99%) in 18% of aneurysms. The overall rate of ischemic and hemorrhagic complications was 8% and 1.1%, respectively. Symptomatic and permanent complications were encountered in 5.7% and 2.3% of patients respectively, with retreatment pursued in 2.3% of patients. Jailed branch occlusion was detected in 11.5% of cases, with clinical sequelae in 2.3%. Last follow-up modified Rankin Scale of 0-2 was noted in 96.8% of patients. On multivariate analysis, male sex was the only independent predictor of aneurysmal persistence at last follow-up imaging (p=0.019).

CONCLUSION

FDS treatment for MCA bifurcation aneurysms is feasible, with comparable safety and efficacy profiles to other available endovascular options when utilized in carefully selected aneurysms. Jailing of M2 branches was not associated with a higher risk of post-procedural ischemic complications.

Anatomic Risk Factors for S1 Segment Superior Cerebellar Artery Aneurysm Rupture: A Radiologic Study on 81 Consecutive Patients

BACKGROUND

Due to treatment associated risks, it is still debatable which unruptured aneurysm should be treated. Anatomic and morphologic characteristics may aid to predict the rupture risk of superior cerebellar artery (SCA) aneurysm and possibly support in decision- making during treatment.

OBJECTIVES

To identify morphologic characteristics that could predict the rupture of SCA aneurysms.

METHODS

A retrospective analysis of computed tomography angiography images of 81 consecutive patients harboring SCA aneurysm who were treated between 1980 to 2014 at Helsinki University Hospital was performed.

RESULTS

Of the 81 analyzed SCA aneurysms, 30 (37%) were unruptured and remaining 51 (63%) presented with subarachnoid hemorrhage. The mean ± SD size of unruptured SCA aneurysms was 6.2 ± 6.3 mm; mean size of ruptured SCA aneurysms was 5.9 ± 5.4 mm. The mean ± SD aspect ratio was 0.9 ± 0.3 in unruptured and 1.14 ± 0.44 in ruptured SCA aneurysms. The mean ± SD degree angle between basilar artery and aneurysm was 74.7 ± 24.4 in unruptured and 65.9 ± 23 ruptured SCA aneurysms. Patients with ruptured SCA aneurysm showed significantly higher aspect ratio (Mann-Whitney U, P = 0.01) and smaller aneurysm to basilar artery angle (Mann-Whitney U, P = 0.039). Aspect ratio >1.1 had 2.3 times higher risk of rupture (odds ration [OR] 2.3, 95% confidence interval [CI] 0.84-6.34). An aneurysm to basilar angle <70 degrees had 2.8 times higher risk of rupture (OR 2.75, 95% CI 1.086-6.96).

CONCLUSIONS

Ruptured SCA aneurysms are usually small in size. Higher aspect ratio and smaller angle between SCA aneurysm and basilar artery had significantly higher risk of SCA (S1 segment) aneurysm rupture.

A nomogram to predict rupture risk of middle cerebral artery aneurysm

BACKGROUND

Determining the rupture risk of unruptured intracranial aneurysm is crucial for treatment strategy. The purpose of this study was to predict the rupture risk of middle cerebral artery (MCA) aneurysms using a machine learning technique.

METHODS

We retrospectively reviewed 403 MCA aneurysms and randomly partitioned them into the training and testing datasets with a ratio of 8:2. A generalized linear model with logit link was developed using training dataset to predict the aneurysm rupture risk based on the clinical variables and morphological features manually measured from computed tomography angiography. To facilitate the clinical application, we further constructed an easy-to-use nomogram based on the developed model.

RESULTS

Ruptured MCA aneurysm had larger aneurysm size, aneurysm height, perpendicular height, aspect ratio, size ratio, bottleneck factor, and height-width ratio. Presence of a daughter-sac was more common in ruptured than in unruptured MCA aneurysms. Six features, including aneurysm multiplicity, lobulations, size ratio, bottleneck factor, height-width ratio, and aneurysm angle, were adopted in the model after feature selection. The model achieved a relatively good performance with areas under the receiver operating characteristic curves of 0.77 in the training dataset and 0.76 in the testing dataset. The nomogram provided a visual interpretation of our model, and the rupture risk probability of MCA aneurysms can be directly read from it.

CONCLUSION

Our model can be used to predict the rupture risk of MCA aneurysm.

Clinical and radiological outcomes in relation with the anatomical orientation of clipped middle cerebral artery bifurcation aneurysms

BACKGROUND

The middle cerebral artery (MCA) bifurcation represents the most frequent location for intracranial aneurysms. Often, the aneurysmal dome can hide the origin of perforating arteries from the M1 segment during the surgical clipping causing ischemic lesions and worse clinical outcome. The aim of this paper is to analyze the association between the orientation of the aneurysm sac and the clinical and radiological outcomes after surgical clipping.

METHODS

Data from 50 MCA bifurcation clipped aneurysms in 47 patients were collected retrospectively. Three different groups were identified according to the aneurysmal sac orientation: anterior-inferior, posterior and superior. A possible association between the aneurysmal sac projection and the outcome was searched through a univariable logistic regression analysis.

RESULTS

Statistical analysis showed significant correlation between the radiologic evidence of post-operative ischemia in the posterior group (p = 0.046, RR = 1.65) and an increased risk in the superior orientation group (p = 0.145, RR = 1.38). The anterior-inferior group was, instead, significantly associated with no evidence of radiologic ischemia (p = 0.0019, RR = 0.58).

CONCLUSION

The orientation of the aneurysmal dome and sac represents a fundamental feature to be considered during the surgical clipping of the MCA aneurysms. Indeed, its posterior and superior projection is associated with a higher incidence of radiologic ischemic lesions due to the origin of perforating arteries from M1 segment behind the aneurysmal sac. The anterior-inferior orientation, on the contrary, is associated with a lower risk.

"It's Only Brain Surgery": Using 3D Printing and Simulation to Prepare Rural Physicians for the Management of Acute Epidural Hematoma

Patients presenting to rural emergency departments with increased intracranial pressure (ICP) can be challenging to diagnose, manage, and treat and although the presentation is rare, it is associated with high morbidity and mortality. In areas such as Newfoundland and Labrador, Canada, where the majority of the province is located far from tertiary care, this problem can be compounded by adverse weather impeding transport, necessitating that the problem is handled by rural physicians instead of neurosurgical care. However, many rural medical personnel do not receive any formal training in treating increased ICP. In this technical report, we use a low-tech, low-cost, high fidelity 3D printed skull to outline a simulation of increased ICP to better prepare rural physicians and emergency department teams who may encounter such a scenario in their practice in a rural area.

The impact of surgical simulation on patient outcomes: a systematic review and meta-analysis

The use of simulation in surgical training is ever growing. Evidence suggests such training may have beneficial clinically relevant effects. The objective of this research is to investigate the effects of surgical simulation training on clinically relevant patient outcomes by evaluating randomized controlled trials (RCT). PubMed was searched using PRISMA guidelines: "surgery" [All Fields] AND "simulation" [All Fields] AND "patient outcome" [All Fields]. Of 119 papers identified, 100 were excluded for various reasons. Meta-analyses were conducted using the inverse-variance random-effects method. Nineteen papers were reviewed using the CASP RCT Checklist. Sixteen studies looked at surgical training, two studies assessed patient-specific simulator practice, and one paper focused on warming-up on a simulator before performing surgery. Median study population size was 22 (range 3-73). Most articles reported outcome measures such as post-intervention Global Rating Scale (GRS) score and/or operative time. On average, the intervention group scored 0.42 (95% confidence interval 0.12 to 0.71, P = 0.005) points higher on a standardized GRS scale of 1-10. On average, the intervention group was 44% (1% to 87%, P = 0.04) faster than the control group. Four papers assessed the impact of simulation training on patient outcomes, with only one finding a significant effect. We found a significant effect of simulation training on operative performance as assessed by GRS, albeit a small one, as well as a significant reduction to operative time. However, there is to date scant evidence from RCTs to suggest a significant effect of surgical simulation training on patient outcomes.

Morphological Variables Associated With Ruptured Middle Cerebral Artery Aneurysms

BACKGROUND

Geometric factors of intracranial aneurysms and surrounding vasculature could affect the risk of aneurysm rupture. However, large-scale assessments of morphological parameters correlated with intracranial aneurysm rupture in a location-specific manner are scarce.

OBJECTIVE

To investigate the morphological characteristics associated with ruptured middle cerebral artery (MCA) aneurysms.

METHODS

Five hundred sixty-one patients with 638 MCA aneurysms diagnosed between 1990 and 2016 who had available computed tomography angiography (CTA) were included in this study. CTAs were evaluated using the Vitrea Advanced Visualization software for 3-dimensional (3D) reconstruction. Morphological parameters examined in each model included aneurysm projection, wall irregularity, presence of a daughter dome, presence of hypoplastic or aplastic A1 arteries and hypoplastic or fetal posterior communicating arteries (PCoA), aneurysm height and width, neck diameter, bottleneck factor, aspect and size ratio, height/width ratio, and diameters and angles of surrounding parent and daughter vessels. Univariable and multivariable statistical analyses were performed to determine the association of morphological characteristics with rupture of MCA aneurysms. Logistic regression was used to build a predictive MCA score.

RESULTS

Greater bottleneck and size ratio, and irregular, multilobed, temporally projecting MCA aneurysms are associated with higher rupture risk, whereas higher M1/M2 ratio, larger width, and the presence of an ipsilateral or bilateral hypoplastic PCoA were inversely associated with rupture. The MCA score had good predictive capacity with area under the receiver operating curve = 0.88.

CONCLUSION

These practical morphological parameters specific to MCA aneurysms are easy to assess when examining 3D reconstructions of unruptured aneurysms and could aid in risk evaluation in these patients.

Safety and efficacy of different therapeutic strategies in the endovascular treatment of anterior cerebral artery aneurysms with different features: A single centre experience

BACKGROUND

Outcomes of endovascular treatment of anterior cerebral artery (ACA) aneurysms are still not well-characterized.

OBJECTIVE

The study aimed to review the clinical effect, procedure-related complications and follow-up outcomes and to evaluate the safety and efficacy of endovascular treatment of ACA aneurysms in our center experience.

METHODS

From August 2014 to August 2018, a total of 75 consecutive patients with 77 ACA aneurysms were treated via the endovascular approach after providing informed consent. A retrospective review of the clinical, radiological, and endovascular details of these patients was conducted.

RESULTS

The mortality and the morbidity in this study were 4% and 9.3%, respectively. Compared with A1 and A2 aneurysms, intraoperative rupture was more common in A3 aneurysms (P = 0.029). Difference between the ruptured and unruptured aneurysms in the distribution of therapeutic strategy (P = 0.003) and immediate embolization degree (P = 0.004) was also significant. Statistical analysis demonstrated that the larger aneurysm (P = 0.031) was, the greater the ratio of aneurysm size to parent artery diameter (P = 0.029) was, the more likely the unruptured aneurysms were to occur ischemic events. Higher Hunt-Hess grade (P = 0.0066) was an independent risk factor for poor clinical outcome.

CONCLUSION

Endovascular treatment is feasible and effective for ACA aneurysms.

Morphology parameters for rupture in middle cerebral artery mirror aneurysms

Objective

To identify the morphological parameters correlated with the rupture of middle cerebral artery (MCA) aneurysms.

Methods

We retrospectively analyzed the digital subtraction angiography (DSA) data of 48 patients with ruptured mirror MCA aneurysms. Morphological parameters included aneurysm with wall protrusion, maximum diameter (Dmax), height, neck width, aneurysm width, dome projection, parent artery average diameter (Dp), aspect ratio (AR), bottleneck factor (BNF), size ratio (SR), M1/M2 ratio, and height/width (H/W) ratio. These paired parameters were analyzed by conditional univariate and multivariate logistic regressions to screen out the independent risk factors. We established a score based on the independent risk factors. Receiver operating characteristics (ROC) were generated to estimate the prediction performance of the score in our large database of 763 aneurysms.

Results

In the univariate regressions, Dmax, height, aneurysm width, neck width, AR, BNF, H/W ratio, SR, anterior dome projection and aneurysm with wall protrusion were significant risk factors. Aneurysm width (OR 3.296, p=0.015), AR (OR 11.594, p=0.014) and anterior dome projection (OR 9.385, p=0.016) were independent risk factors in multivariate regression. The area under the curve (AUC) value of the score based on the three independent risk factors was 0.829.

Conclusion

Aneurysm width, AR and anterior dome projection were independent risks factors of rupture.

Morphological predictors of middle cerebral artery bifurcation aneurysm rupture

OBJECTIVE

Middle cerebral artery (MCA) bifurcation aneurysms are more likely to be associated with severe hemorrhage or hematoma in a clinical setting. We aimed to investigate the morphological predictors of MCA bifurcation aneurysm rupture.

PATIENTS AND METHODS

We conducted a retrospective analysis of 317 patients with MCA aneurysms between January 2009 and October 2016. Aneurysm status was grouped into ruptured and unruptured groups. The MCA bifurcation was defined as the bifurcation of the main trunk (the origin of the M2 trunks). Aneurysm morphologies were determined using CT angiography. We performed univariate and multivariable regression analyses to investigate the association of morphological characteristics with ruptured MCA bifurcation aneurysms.

RESULTS

A total of 268 (84.5 %) patients with 280 MCA bifurcation aneurysms were included. 207 (73.9 %) aneurysms had ruptured. In the univariate analysis, a larger aneurysm (p = 0.042), a larger size ratio (p = 0.001), a larger aspect ratio (p = 0.017), a greater bottleneck ratio (p = 0.047), an irregular aneurysm (p = 0.004) and the presence of a daughter dome (p = 0.002) were associated with aneurysm rupture. The multivariate analysis showed that a larger size ratio (OR 1.324, 95 % CI, 1.062-1.651; p = 0.013) and the presence of daughter dome (OR 2.462, 95 % CI, 1.123-5.398; p = 0.024) were independently associated with ruptured aneurysms. The threshold of the size ratio for discriminating ruptured and unruptured aneurysms was 2.53 (p < 0.001).

CONCLUSIONS

The size ratio and the presence of a daughter dome were independent predictors of the rupture of MCA bifurcation aneurysms. These parameters may contribute to the evaluation of the risk of rupture of aneurysms.

Risk Factors for Intracranial Aneurysm Rupture: A Systematic Review

BACKGROUND

Intracranial aneurysm rupture prediction is poor, with only a few risk factors for rupture identified and used in clinical practice.

OBJECTIVE

To provide an overview of all the risk factors (including genetic, molecular, morphological, and hemodynamic factors) that have potential for use in clinical practice.

METHODS

We systematically searched PubMed and EMBASE and focused on factors that can be easily assessed in clinical practice, might be used for rupture prediction in clinical practice, and/or are potential targets for further research. Studies were categorized according to methodological quality, and a meta-analysis was performed, if possible.

RESULTS

We included 102 studies describing 144 risk factors that fulfilled predefined criteria. There was strong evidence for the morphological factors irregular shape (studied in 4 prospective cohort studies of high-quality, pooled odds ratio [OR] of 4.8 [95% confidence interval 2.7-8.7]), aspect ratio (pooled OR 10.2 [4.3-24.6]), size ratio, bottleneck factor, and height-to-width ratio to increase rupture risk. Moderate level of evidence was found for presence of contact with the perianeurysmal environment (pooled OR 3.5 [1.4-8.4]), unbalanced nature of this contact (pooled OR 17.8 [8.3-38.5]), volume-to-ostium ratio, and direction of the aneurysm dome (pooled OR 1.5 [1.2-1.9]).

CONCLUSION

Irregular aneurysm shape was identified as a risk factor with potential for use in clinical practice. The risk factors aspect ratio, size ratio, bottleneck factor, height-to-width ratio, contact with the perianeurysmal environment, volume-to-ostium ratio, and dome-direction should first be confirmed in multivariate analysis and incorporated in prediction models.

Simulation-based Education for Endoscopic Third Ventriculostomy: A Comparison Between Virtual and Physical Training Models

BACKGROUND

The relative educational benefits of virtual reality (VR) and physical simulation models for endoscopic third ventriculostomy (ETV) have not been evaluated "head to head."

OBJECTIVE

To compare and identify the relative utility of a physical and VR ETV simulation model for use in neurosurgical training.

METHODS

Twenty-three neurosurgical residents and 3 fellows performed an ETV on both a physical and VR simulation model. Trainees rated the models using 5-point Likert scales evaluating the domains of anatomy, instrument handling, procedural content, and the overall fidelity of the simulation. Paired t tests were performed for each domain's mean overall score and individual items.

RESULTS

The VR model has relative benefits compared with the physical model with respect to realistic representation of intraventricular anatomy at the foramen of Monro (4.5, standard deviation [SD] = 0.7 vs 4.1, SD = 0.6; P = .04) and the third ventricle floor (4.4, SD = 0.6 vs 4.0, SD = 0.9; P = .03), although the overall anatomy score was similar (4.2, SD = 0.6 vs 4.0, SD = 0.6; P = .11). For overall instrument handling and procedural content, the physical simulator outperformed the VR model (3.7, SD = 0.8 vs 4.5; SD = 0.5, P < .001 and 3.9; SD = 0.8 vs 4.2, SD = 0.6; P = .02, respectively). Overall task fidelity across the 2 simulators was not perceived as significantly different.

CONCLUSION

Simulation model selection should be based on educational objectives. Training focused on learning anatomy or decision-making for anatomic cues may be aided with the VR simulation model. A focus on developing manual dexterity and technical skills using endoscopic equipment in the operating room may be better learned on the physical simulation model.

[Human patient simulators for training in emergency surgery : Needs, status quo and potential]

Surgical providers must maintain currency and competency for low-volume high-risk procedures for optimal outcomes. There are currently a number of methods available to train for these rare but vital skills, ranging from simple to complex and inexpensive to expensive. Traditionally, these skills have been taught using human cadaveric and animal models, which are limited by availability (cadavers) and social acceptability (animals). As such, there is a need to utilize advances in educational and simulation technologies to refine and develop consensus-based, validated, tissue-realistic, anatomically correct and cost-effective training tools to teach these vital skills. Partially perfused human cadavers have recently been shown to be an important adjunct to established trauma training. Human patient simulators (HPS) and the associated technology is rapidly expanding, but currently lack consistent realism to be used for competence training, when compared to traditional models and are currently cost-prohibitive. It will be important for surgical trainers and trainees to remain engaged and facilitate the development of realistic cost-effective training tools.

Optical Coherence Tomography for Intracranial Aneurysms: A New Method for Assessing the Aneurysm Structure

BACKGROUND

There is a lack of precise methods for predicting the risk of aneurysm rupture. Therefore, prophylactic treatment is used, which leads to unnecessary potential complications. A new modality enabling a more accurate risk assessment is needed. Optical coherence tomography (OCT) is a new-generation imaging technology that has astonishing resolution for vascular imaging. In this study, OCT was used for the evaluation of intracranial aneurysms.

METHODS

In vivo OCT imaging was performed for aneurysms induced in 6 rabbits and in 9 intracranial aneurysm patients. Catheters were cut short to prevent any extra length from damaging aneurysms and tissues. Images of both the parent artery and the aneurysm at multiple viewing angles were obtained using rotational OCT scanning.

RESULTS

The OCT images of rabbits correlated well with histologic sections. The 3-layered architecture of the parent arteries was explicitly shown. Ruptured intracranial aneurysms manifested complete breakdown of the wall structure; however, this was not observed in any unruptured aneurysms. The OCT images of unruptured intracranial aneurysms demonstrated a trend of degradation by showing the gradual disappearance of the demarcation between the layers or incomplete apoptosis in layer structures.

CONCLUSION

OCT is the most precise imaging modality because it provides detailed information regarding the aneurysm structures, thus enabling more distinct insight into the vascular construction of intracranial aneurysms.

Evaluation of the risk of rupture of intracranial aneurysms in patients with aneurysmal subarachnoid hemorrhage according to the PHASES score

The PHASES score was developed to determine the risk of rupture of un-ruptured intracranial aneurysms (UIAs). The purposes of the current study were to apply this score on patients with actually ruptured intracranial aneurysms and to analyze the hypothetically prediction of the risk in this particularly patient group. We extracted the data of 100 recently treated patients (23 male, 77 female, mean age 56.4 years, range 17-93 years) with ruptured saccular intracranial aneurysms from our prospectively maintained neurovascular database according to the parameters used in the PHASES score (population, hypertension, age, earlier SAH, size and site of the aneurysm). Descriptive statistical analysis was performed using SPSS for Windows version 18.0 (SPSS Inc., Chicago, Illinois, USA). Ninety-nine percent of the patients were European and 1% Japanese in our series. Pre-existing arterial hypertension was found in 59%. Fifteen percent of the patients were > 75 years. Earlier SAH was found in 1%. The site of the aneurysms were the internal carotid artery (ICA) in 10%, the middle cerebral artery (MCA) in 14%, and arteries of the anterior and posterior circulation (PC) including the posterior communicating artery (PCOM) in 76%. Sixty-six percent of the aneurysms were smaller than 7 mm, 18% ranged between 7 and 9.9 mm, 14% were between 10 and 19.9 mm, and 2% were larger than 20 mm. European population, aneurysm size < 7 mm, and age < 75 years scored with 0 point in the PHASES study occurred most frequently in our series. The distribution of the aneurysm site to the anterior and posterior circulation scored with 4 points occurred most frequently. Considering the 5-year risk of rupture, 70% of our patient collective would have an estimated risk of < 2%. Interestingly, 70% of the patients with aneurysmal SAH had a low risk profile and would have a low risk of rupture according to the PHASES score in our series. This observation underlines the discrepancy of the estimated low risk of rupture for UIAs in young and healthy patients and the obvious fact the majority of the SAH patients are actually young with low risk factors. Parameters beyond the features of the PHASES score are needed to determine the risk of rupture of intracranial aneurysms.

Anatomic Features of Paraclinoid Aneurysms: Computed Tomography Angiography Study of 144 Aneurysms in 136 Consecutive Patients

BACKGROUND

Paraclinoid aneurysms are among the most challenging aneurysms to treat. Computed tomography (CT) angiography helps in evaluating the radiological characteristics of these aneurysms next to bony structures.

OBJECTIVE

To present the CT angiography characteristics of paraclinoid aneurysms in order to better understand such pathology.

METHODS

The study examined CT angiography-based anatomical characteristics obtained retrospectively from 136 patients with 144 paraclinoid aneurysms selected from single-defined catchment populations in Finland. We examined the diameters of the parent artery (internal carotid artery), the location of the aneurysm, its dimensions (width, height, neck), and aneurysm wall irregularity.

RESULTS

We analyzed 144 paraclinoid aneurysms in 136 patients admitted to the hospital during 2000-2014. Multivariable analysis reveals that rupture aneurysms have the following radiological features: aneurysm larger than 5 mm in diameter (P = .006), irregular wall (P = .046), superior location, larger aspect ratio (P = .039), and neck wider than parent artery (P < .001).

CONCLUSION

Smaller diameter of the internal carotid artery and superior location, as well as a large and irregular aneurysm wall, are radiological characteristics of ruptured paraclinoid aneurysms, which CT angiography can measure easily.

A Facial Trauma Simulation Course for Evaluation and Treatment of Facial Fractures

Importance

Traditional facial trauma laboratories are used for teaching basic concepts of fracture reduction and hardware manipulation. Facial trauma simulation laboratories allow training physicians the opportunity to develop unique treatment plans as they would in real patient encounters.

Objective

To assess the value of a novel facial trauma simulation course requiring residents to practice advanced decision making.

Design, Setting, and Participants

Data were prospectively collected July 23 and August 23 and 24, 2016, in a survey study during a resident physician trauma simulation course. Fresh frozen cadaver heads were fractured using an impactor that applied a measurable amount of force. Each head was scanned with high-resolution computed tomography. Residents were paired and tasked with evaluating their specimen's imaging findings and developing a treatment plan.

Main Outcomes and Measures

Before the course, residents were asked their postgraduate year level, number of facial fractures treated as a resident surgeon, and their comfort level based on the Otolaryngology Milestone for Facial Trauma (OMFT; ratings range from 0-5, with 5 indicating equivalent to fellow-level experience). After the course, residents were asked to assess the course's value relative to a theoretical number of actual operative cases, and a posttraining OMFT assessment was obtained.

Results

Thirty resident physicians completed the course at 2 institutions. Residents represented an equivalent distribution of postgraduate year levels. The residents stated that the course was worth a mean (SD) of 6.4 (2.8) operative cases of facial trauma in terms of surgical learning. The mean change in self-reported OMFT rating after the course was 0.87 (95% CI, 0.67-1.07; P < .001, paired t test). On the basis of this change in self-perceived OMFT rating, the course was deemed to be worth 1.5 years of residency training in the management of facial fractures.

Conclusion and Relevance

Conducting a facial trauma simulation course increases resident experience with advanced surgical decision making.

Level of Evidence

NA.

Anterior Communicating Artery Aneurysm Morphology and the Risk of Rupture

BACKGROUND

Recently, with improvements in computed tomography angiography and digital subtraction angiography, the assessment of certain morphologic traits of anterior communicating artery aneurysms (ACoAA) has drawn great attention. The determination of specific factors associated with rupture would provide much-needed guidance for the treatment of unruptured intracranial aneurysms, such as surgical clipping or endovascular coiling. Morphologic factors include, but are not limited to, aneurysm size, number, shape, dome direction, neck/dome ratio, and relationship of the aneurysm to the surrounding vessels. However, the results of previous investigations concerning morphologic parameters have yielded inconsistent results.

METHODS

This review presents and analyzes the literature on the morphology of ACoAAs and risk of rupture.

RESULTS

This literature review reveals that the strongest predictors of ACoAA rupture are size ratio, direction of the dome, and fenestration. These were the only factors that were either unanimously or near unanimously found to be predictive of rupture across multiple studies.

CONCLUSIONS

The size ratio, direction of the dome, and fenestration should be examined most meticulously when deciding when to treat an ACoAA.

Morphological and Hemodynamic Parameters for Middle Cerebral Artery Bifurcation Aneurysm Rupture Risk Assessment

OBJECTIVE

To investigate the morphological and hemodynamic parameters associated with middle cerebral artery (MCA)bifurcation aneurysm rupture.

METHODS

A retrospective study of 67 consecutive patients was carried out based on 3D digital subtraction angiography data. Morphological and hemodynamic parameters including aneurysm size parameters (dome width, height, and perpendicular height), longest dimension from the aneurysm neck to the dome tip, neck width, aneurysm area, aspect ratio, Longest dimension from the aneurysm neck to the dome tip (Dmax) to dome width, and height-width, Bottleneck factor, as well as wall shear stress (WSS), low WSS area (LSA), percentage of LSA (LSA%) and energy loss (EL) were estimated. Parameters between ruptured and un-ruptured groups were analyzed. Receiver operating characteristics were generated to check prediction performance of all significant variables.

RESULTS

Sixty-seven patients with MCA bifurcation aneurysm were included (31 unruptured, 36 ruptured). Dmax (p=0.008) was greater in ruptured group than that in un-ruptured group. D/W (p<0.001) and the percentage of the low WSS area (0.09±0.13 vs. 0.01±0.03, p<0.001) were also greater in the ruptured group. Moreover, the EL in ruptured group was higher than that in un-ruptured group (6.39±5.04 vs. 1.53±0.86, p<0.001). Multivariate regression analysis suggested D/W and EL were significant predictors of rupture of MCA bifurcation aneurysms. Correlation analyses revealed the D/W value was positively associated with the EL (R=0.442, p<0.01).

CONCLUSION

D/W and EL might be the most two favorable factors to predict rupture risk of MCA bifurcation aneurysms.

Predictive anatomical factors for rupture in middle cerebral artery mirror bifurcation aneurysms

OBJECTIVE The aim of this study was to define predictive factors for rupture of middle cerebral artery (MCA) mirror bifurcation aneurysms. METHODS The authors retrospectively analyzed the data in patients with ruptured MCA bifurcation aneurysms with simultaneous presence of an unruptured MCA bifurcation mirror aneurysm treated in two neurosurgical centers. The following parameters were measured and analyzed with the statistical software R: neck, dome, and width of both MCA aneurysms-including neck/dome and width/neck ratios, shape of the aneurysms (regular vs irregular), inflow angle of both MCA aneurysms, and the diameters of the bilateral A₁ and M₁ segments and the frontal and temporal M₂ trunks, as well as the bilateral diameter of the internal carotid artery (ICA). RESULTS The authors analyzed the data of 44 patients (15 male and 29 female, mean age 50.1 years). Starting from the usual significance level of 0.05, the Sidak-corrected significance level is 0.0039. The diameter of the measured vessels was statistically not significant, nor was the inflow angle. The size of the dome was highly significant (p = 0.0000069). The size of the neck (p = 0.0047940) and the width of the aneurysms (p = 0.0056902) were slightly nonsignificant at the stated significance level of 0.0039. The shape of the aneurysms was bilaterally identical in 22 cases (50%). In cases of asymmetrical presentation of the aneurysm shape, 19 (86.4%) ruptured aneurysms were irregular and 3 (13.6%) had a regular shape (p = 0.001). CONCLUSIONS In this study the authors show that the extraaneurysmal flow dynamics in mirror aneurysms are nonsignificant, and the aneurysmal geometry also does not seem to play a role as a predictor for rupture. The only predictors for rupture were size and shape of the aneurysms. It seems as though under the same conditions, one of the two aneurysms suffers changes in its wall and starts growing in a more or less stochastic manner. Newer imaging methods should enable practitioners to see which aneurysm has an unstable wall, to predict the rupture risk. At the moment one can only conclude that in cases of MCA mirror aneurysms the larger one, with or without shape irregularities, is the unstable aneurysm and that this is the one that needs to be treated.

The Rupture Risk of Aneurysm in the Anterior Communicating Artery: A Single Center Study

Objective

The aim of this study was to evaluate the characteristics of ruptured aneurysms at anterior communicating artery (A com) with an analysis of clinical and morphological data, which could further our understanding of the risks of ruptured A com aneurysms.

Materials and Methods

An analysis of data with 86 ruptured and 44 unruptured A com aneurysms were analyzed using a digital subtraction angiography or 3-dimensional computed tomography angiography between January 2010 and December 2015 in a single center.

Results

Fifty-five percent of ruptured A com aneurysms were smaller than 4 mm in size. They had a smooth wall (44%), with a mean size ratio of 4.22 (range: 0.7-14.3) and mean height/width ratio of 1.48 (range: 0.5-2.9); 23 patients of A1 positive difference. Unruptured aneurysms were mostly 2-10 mm in size (94%) and had an irregular wall (43%), with a mean size ratio of 4.1 (range: 0.8-9.1) and mean height/width ratio of 1.2 (range: 0.1-2.6); 6 patients of A1 positive difference. In terms of the morphology of aneurysms, size of A com, maximum aneurysm size, neck width, aneurysm wall morphology, and size ratio were not different with statistical significance. However, dominance of A1 (p = 0.01) and height/width ratio (p = 0.03) were found to be a significant predictive factor for rupture of A com aneurysms.

Conclusion

To better understand the rupture risk of A com aneurysms, a large, multicenter, collaborative, and prospective study should be performed in the future.

Flow Diversion for the Treatment of MCA Bifurcation Aneurysms-A Single Centre Experience

Background

Intracranial aneurysms located at the bifurcation of the middle cerebral artery (MCA) can often be challenging for the neurointerventionalist. We aimed to evaluate the efficacy and safety of flow diverting stents (FDS) in the treatment of these aneurysms.

Materials and methods

We retrospectively reviewed our prospectively maintained database to collect information for all patients with unruptured saccular bifurcation MCA aneurysms treated with FDS between January 2010 and January 2016. In addition to demographic data, we recorded the location, aneurysm characteristics, previous treatments, number and type of FDS, complications, and clinical and angiographic follow-up.

Results

Our search identified 13 patients (7 males) with an average age of 61.7 years (47–74 years). All patients had a single bifurcation aneurysm of the MCA, and none of the aneurysms were acutely ruptured. The average fundus size of the saccular aneurysms was 3 mm (range 1.5–10 mm). Follow-up studies were available for 12 patients. Based on the most recent follow-up angiograms, six aneurysms (50%) were totally occluded; five aneurysms (41.7%) showed only a small remnant; and one aneurysm (8.3%) remained unchanged. One patient suffered from an ischemic stroke with resultant permanent hemiparesis (mRS 3). In another case, there was an in-stent thrombosis during the intervention, which resolved upon intra-arterial infusion of Eptifibatide (mRS 0). There were no intra-operative vessel or aneurysm ruptures and no mortalities. Angiography of the covered MCA branches showed no change in the caliber or flow of the vessel in six (50%), a reduction in caliber in five (41.7%), and a complete occlusion in one (8.3%). All caliber changes and occlusions of the vessels were asymptomatic.

Conclusion

In our series, 91.7% of treated MCA bifurcation aneurysms were either completely occluded or showed only a small remnant with a good safety profile. Flow diversion of MCA bifurcation aneurysms should be considered as an alternative treatment strategy when microsurgical clipping or alternative endovascular treatment options are not feasible.

Risk Factors for the Rupture of Middle Cerebral Artery Bifurcation Aneurysms Using CT Angiography

BACKGROUND AND PURPOSE

To investigate the clinical and morphological characteristics associated with risk factors for the rupture of bifurcation-type middle cerebral artery aneurysms (MCAAs).

METHODS

A total of 169 consecutive patients with 177 bifurcation-type MCAAs were reviewed from August 2011 to January 2016. Based on the clinical and morphologic characteristics findings, the risk factors of aneurysm rupture were assessed using statistical methods.

RESULTS

Age, cerebral atherosclerosis, no hypertension, hypertension grade 2 and coronary artery disease (CAD) were negatively correlated with aneurysm rupture. The mean diameter (MD) of the parent and two daughter arteries was negatively correlated with rupture. Aneurysms with irregularity, depth, width, maximum size, aspect ratio, depth-to-width ratio, bottleneck factor, and size ratio were positively correlated with rupture. The multivariate logistic regression model revealed that irregular shape (odds ratio (OR) 2.697) and aspect ratio (OR 3.723) were significantly and positively correlated with rupture, while cerebral atherosclerosis (OR 0.033), CAD (OR 0.080), and MD (OR 0.201) were negatively correlated with rupture. Receiver operating characteristic analysis revealed that the threshold value of the aspect ratio and MD were 0.96 and 2.43 mm, respectively.

CONCLUSIONS

Cerebral atherosclerosis and CAD are protective factors against rupture. Morphological characteristics such as an aneurysm with an irregular shape, a high aspect ratio (>0.96) and a small MD (<2.43 mm) are likely better predictors of rupture.

Management of Unruptured Saccular Aneurysms of the M1 Segment with Flow Diversion : A Single Centre Experience

PURPOSE

The optimal strategy for the treatment of M1 segment aneurysms has not yet been determined as both standard microneurosurgical and endovascular techniques can pose challenges. We sought to determine the efficacy of flow diverting stents to treat small, unruptured aneurysms of the M1 segment.

METHODS

We retrospectively reviewed our database of prospectively collected information for all patients treated with flow diversion for an unruptured saccular aneurysm of the middle cerebral artery (MCA) between February 2009 and February 2016. The relationship to early cortical branches, aneurysm fundus size, number and type of flow diverting stent (FDS), complications and follow-up data were recorded.

RESULTS

In total 15 patients were identified that matched our inclusion criteria (11 female and 4 male). The average age of the patients was 58.3 years (range 14-76 years). All patients had a single aneurysm affecting the M1 segment of the MCA, 10 (66.6%) of which were related to early cortical branches and 10 aneurysms were located on the left (66.6%). The average aneurysm fundus size was 3 mm (range 2-9 mm) and 13 patients had follow-up angiographic studies. In total, 8 aneurysms were completely excluded, and 6 remained incompletely occluded (3 modified Raymond-Roy classification [mRRC] II and 3 mRRC IIIa). One patient suffered a stroke and another patient had an iatrogenic vessel dissection that was not flow limiting.

CONCLUSION

Flow diversion can be used to treat small, unruptured aneurysms of the M1 segment of the MCA and even though side vessel occlusion can occur clinically relevant infarction occurs infrequently.

Simulator-Based Angiography and Endovascular Neurosurgery Curriculum: A Longitudinal Evaluation of Performance Following Simulator-Based Angiography Training

This study establishes performance metrics for angiography and neuroendovascular surgery procedures based on longitudinal improvement in individual trainees with differing levels of training and experience.

Over the course of 30 days, five trainees performed 10 diagnostic angiograms, coiled 10 carotid terminus aneurysms in the setting of subarachnoid hemorrhage, and performed 10 left middle cerebral artery embolectomies on a Simbionix Angio Mentor™ simulator. All procedures were nonconsecutive. Total procedure time, fluoroscopy time, contrast dose, heart rate, blood pressures, medications administered, packing densities, the number of coils used, and the number of stent-retriever passes were recorded. Image quality was rated, and the absolute value of technically unsafe events was recorded. The trainees’ device selection, macrovascular access, microvascular access, clinical management, and the overall performance of the trainee was rated during each procedure based on a traditional Likert scale score of 1=fail, 2=poor, 3=satisfactory, 4=good, and 5=excellent. These ordinal values correspond with published assessment scales on surgical technique.

After performing five diagnostic angiograms and five embolectomies, all participants demonstrated marked decreases in procedure time, fluoroscopy doses, contrast doses, and adverse technical events; marked improvements in image quality, device selection, access scores, and overall technical performance were additionally observed (p < 0.05). Similarly, trainees demonstrated marked improvement in technical performance and clinical management after five coiling procedures (p < 0.05). However, trainees with less prior experience deploying coils continued to experience intra-procedural ruptures up to the eighth embolization procedure; this observation likely corresponded with less tactile procedural experience to an exertion of greater force than appropriate for coil placement.

Trainees across all levels of training and prior experience demonstrated a significant performance improvement after completion of our simulator curriculum consisting of five diagnostic angiograms, five embolectomy cases, and 10 aneurysm coil embolizations.

Vertebral artery-posterior inferior cerebellar artery convergence aneurysms treated by endovascular or surgical treatment: Mid- and long-term outcome

INTRODUCTION

Management of vertebral artery-posterior inferior cerebellar artery convergence (VA-PICA) saccular aneurysms requires a specialized neurovascular team. The objective is to preserve the functional outcome while performing a complete and reliable long-term exclusion of the aneurysm.

OBJECTIVE

The aim of our study was to evaluate the outcome of patients with VA-PICA saccular aneurysms after treatment.

MATERIALS AND METHODS

This was a retrospective series of 21 consecutive patients with a VA-PICA saccular aneurysm treated between 2000 and 2012 at our institution. Treatment option (endovascular or microsurgical) was decided for each patient following a multidisciplinary discussion.

RESULTS

Twenty-one patients were treated for a VA-PICA saccular aneurysm including 16 for a ruptured aneurysm and 5 for an asymptomatic aneurysm. Among all patients, 11 underwent endovascular treatment and 10 had microsurgical treatment. Our results showed a major aneurysm recurrence after endovascular treatment in 3 patients that required a further endovascular treatment in 2 cases. These 3 major recurrences occurred after treatment of a ruptured aneurysm when the initial angiography demonstrated the origin of the PICA at the neck of the aneurysm. After microsurgery, angiography showed a remnant neck in 2 patients including 1 treated by further endovascular procedure.

CONCLUSION

VA-PICA aneurysms are rare and require multidisciplinary management. Microsurgical treatment should be discussed when the PICA originates from the aneurysmal neck, particularly in patients with a ruptured small aneurysm, in order to obtain a reliable and long-term exclusion of the aneurysm.

Virtual reality cerebral aneurysm clipping simulation with real-time haptic feedback

BACKGROUND

With the decrease in the number of cerebral aneurysms treated surgically and the increase of complexity of those treated surgically, there is a need for simulation-based tools to teach future neurosurgeons the operative techniques of aneurysm clipping.

OBJECTIVE

To develop and evaluate the usefulness of a new haptic-based virtual reality simulator in the training of neurosurgical residents.

METHODS

A real-time sensory haptic feedback virtual reality aneurysm clipping simulator was developed using the ImmersiveTouch platform. A prototype middle cerebral artery aneurysm simulation was created from a computed tomographic angiogram. Aneurysm and vessel volume deformation and haptic feedback are provided in a 3-dimensional immersive virtual reality environment. Intraoperative aneurysm rupture was also simulated. Seventeen neurosurgery residents from 3 residency programs tested the simulator and provided feedback on its usefulness and resemblance to real aneurysm clipping surgery.

RESULTS

Residents thought that the simulation would be useful in preparing for real-life surgery. About two-thirds of the residents thought that the 3-dimensional immersive anatomic details provided a close resemblance to real operative anatomy and accurate guidance for deciding surgical approaches. They thought the simulation was useful for preoperative surgical rehearsal and neurosurgical training. A third of the residents thought that the technology in its current form provided realistic haptic feedback for aneurysm surgery.

CONCLUSION

Neurosurgical residents thought that the novel immersive VR simulator is helpful in their training, especially because they do not get a chance to perform aneurysm clippings until late in their residency programs.

Morphology Parameters for Mirror Posterior Communicating Artery Aneurysm Rupture Risk Assessment

Recent studies have shown that posterior communicating artery (PComA) aneurysms are more likely to rupture. However, surgical intervention for PComA aneurysms may be associated with increased treatment-related morbidity rate. Therefore, it is meaningful to investigate the factors related to PComA aneurysm rupture. The purpose of this study was to identify morphological parameters that significantly correlate with PComA aneurysm rupture. We divided 14 pairs of mirror posterior communicating artery aneurysms (PComA-MANs) into ruptured and unruptured groups. Computed tomography angiography (CTA) imaging was evaluated with three-dimensional (3D) Slicer to generate models of the aneurysms and surrounding vasculature. Nine morphological parameters [size, height, width, neck width, aspect ratio (AR), bottleneck factor (BNF), height/width ratio (H/W), size ratio (SR), and bleb formation] were examined in the two groups for significance with respect to rupture. By contrast, statistically significant differences were found in ruptured and unruptured group for size, AR, BNF, SR, and bleb formation (P < 0.05). Parameters that had no significant differences between the two groups were height (P = 0.103), width (P = 0.078), neck width (P = 0.808), and H/W (P = 0.417). We conclude that MANs may be a useful model for the morphological analysis of intracranial aneurysm rupture. Larger size, higher AR, BNF, SR, and bleb formation may be related to rupture of PComA aneurysms. Larger sample studies minimizing the interference from patient-related factors and aneurysm type were expected for acquiring more accurate assessment of the relationship between these parameters and PComA aneurysm rupture.

An integrated, ontology-driven approach to constructing observational databases for research

The electronic health record (EHR) contains a diverse set of clinical observations that are captured as part of routine care, but the incomplete, inconsistent, and sometimes incorrect nature of clinical data poses significant impediments for its secondary use in retrospective studies or comparative effectiveness research. In this work, we describe an ontology-driven approach for extracting and analyzing data from the patient record in a longitudinal and continuous manner. We demonstrate how the ontology helps enforce consistent data representation, integrates phenotypes generated through analyses of available clinical data sources, and facilitates subsequent studies to identify clinical predictors for an outcome of interest. Development and evaluation of our approach are described in the context of studying factors that influence intracranial aneurysm (ICA) growth and rupture. We report our experiences in capturing information on 78 individuals with a total of 120 aneurysms. Two example applications related to assessing the relationship between aneurysm size, growth, gene expression modules, and rupture are described. Our work highlights the challenges with respect to data quality, workflow, and analysis of data and its implications toward a learning health system paradigm.

Morphological Parameters Associated With Middle Cerebral Artery Aneurysms

BACKGROUND:

Morphological factors contribute to the hemodynamics of the middle cerebral artery (MCA).

OBJECTIVE:

To identify image-based morphological parameters that correlated with the presence of MCA aneurysms.

METHODS:

Image-based anatomic parameters obtained from 110 patients with and without MCA bifurcation aneurysms were evaluated with Slicer, an open-source image analysis software, to generate 3-dimensional models of the aneurysms and surrounding vascular architecture. We examined segment lengths, diameters, and vessel-to-vessel angles of the parent and daughter vessels at the MCA bifurcation. In order to reduce confounding by genetic and clinical risk factors, 2 control groups were selected: group A (the unaffected contralateral side of patients with unilateral MCA bifurcation aneurysms) and group B (patients without intracranial aneurysms or other vascular malformations). Univariate and multivariate analyses were performed to determine statistical significance.

RESULTS:

One hundred ten patients who were evaluated from 2007 to 2014 were analyzed (73 patients with MCA aneurysms and 37 control patients). Multivariate analysis revealed that a smaller parent artery diameter (group A: odds ratio [OR] 0.20, P &lt; .01, group B: OR 0.23, P &lt; .01) and a larger daughter-to-daughter branch angle (group A: OR 1.01, P = .04, group B: OR 1.02, P = .04) were most strongly associated with MCA aneurysm presence after adjusting for other morphological factors.

CONCLUSION:

Smaller parent artery diameter and larger daughter-to-daughter branch angles are associated with the presence of MCA bifurcation aneurysms. These easily measurable parameters may provide objective metrics to assess aneurysm formation and growth risk stratification in high-risk patients.

Observation of cerebral aneurysm wall thickness using intraoperative microscopy: clinical and morphological analysis of translucent aneurysm

Intracranial aneurysms suffer various interactions between hemodynamics and pathobiology, and rupture when this balance disrupted. Aneurysm wall morphology is a result of these interactions and reflects the quality of the maturation. However, it is a poorly documented in previous studies. The purpose of this study is to observe aneurysm wall thickness and describe the characteristics of translucent aneurysm by analyzing clinical and morphological parameters. 253 consecutive patients who underwent clipping surgery in a single institute were retrospectively analyzed. Only middle cerebral artery aneurysms (MCA) which exposed most part of the dome during surgery were included. Aneurysms were categorized based on intraoperative video findings. Aneurysms more than 90 % of super-thin dome and any aneurysms with entirely super-thin-walled daughter sac were defined as translucent aneurysm. A total of 110 consecutive patients with 116 unruptured MCA aneurysms were included. Ninety-two aneurysms (79.3 %) were assigned to the not-translucent group and 24 (20.7 %) to the translucent group. The relative proportion of translucent aneurysm in each age group was highest at ages 50-59 years and absent at ages 30-39 and 70-79 years. There was a trend that translucent aneurysms were smaller in size (p = 0.019). Multivariate logistic analysis showed that translucent aneurysm was strongly correlated with height <3 mm (p = 0.003). We demonstrated that the translucent aneurysms were smaller in size and the aneurysm height <3 mm was related. These results may provide information in determining treatment strategies in patients with small size aneurysm.

Surgical Management of Ruptured Middle Cerebral Artery Aneurysms With Large Intraparenchymal or Sylvian Fissure Hematomas

BACKGROUND:

Craniotomy for hematoma evacuation and aneurysm clipping is the treatment modality of choice for ruptured middle cerebral artery (MCA) aneurysms with intracranial hematomas. Recent literature suggests that endovascular coil embolization followed by hematoma evacuation can be an acceptable alternative.

OBJECTIVE:

To determine neurological outcomes in patients with ruptured MCA aneurysms and intraparenchymal or sylvian fissure hematomas.

METHODS:

The records of 49 patients with ruptured MCA aneurysms with large intracranial hematomas treated with hematoma evacuation and aneurysm clipping between January 2000 and December 2013 were retrospectively reviewed.

RESULTS:

Within this cohort, 35 patients (71.4%) were Hunt and Hess grade IV or V on presentation. The mean hematoma volume was 100.4 ± 77.2 mL. Craniectomy was performed in 40 patients (81.6%). Angiographic vasospasm developed in 15 patients (30.6%). The in-hospital mortality rate was 28.6% (14 patients). At a mean of 25.3 ± 34.0 months follow-up, a good outcome (modified Rankin Scale [mRS] score 0–3) was observed in 18 patients (36.7%). Significant factors associated with poor outcome or death (mRS scores of 4–6) included increasing age (P &lt; .01), increasing Hunt and Hess grade (P = .03), increasing modified Fisher grade (P = .01), presence of intraventricular hemorrhage (P &lt; .01), decreasing percentage of hematoma evacuation (P &lt; .05), need for craniectomy (P &lt;. 01), need for external ventricular drainage (P = .04), and angiographic vasospasm (P = .02).

CONCLUSION:

MCA aneurysm rupture with concomitant large intraparenchymal or sylvian fissure hematoma formation carries a grave prognosis. Simultaneous hematoma evacuation and aneurysm clipping with or without craniectomy can be an effective treatment modality.

Mixed Reality Ventriculostomy Simulation: Experience in Neurosurgical Residency

BACKGROUND:

Medicine and surgery are turning toward simulation to improve on limited patient interaction during residency training. Many simulators today use virtual reality with augmented haptic feedback with little to no physical elements. In a collaborative effort, the University of Florida Department of Neurosurgery and the Center for Safety, Simulation & Advanced Learning Technologies created a novel “mixed” physical and virtual simulator to mimic the ventriculostomy procedure. The simulator contains all the physical components encountered for the procedure with superimposed 3-D virtual elements for the neuroanatomical structures.

OBJECTIVE:

To introduce the ventriculostomy simulator and its validation as a necessary training tool in neurosurgical residency.

METHODS:

We tested the simulator in more than 260 residents. An algorithm combining time and accuracy was used to grade performance. Voluntary postperformance surveys were used to evaluate the experience.

RESULTS:

Results demonstrate that more experienced residents have statistically significant better scores and completed the procedure in less time than inexperienced residents. Survey results revealed that most residents agreed that practice on the simulator would help with future ventriculostomies.

CONCLUSION:

This mixed reality simulator provides a real-life experience, and will be an instrumental tool in training the next generation of neurosurgeons. We have now implemented a standard where incoming residents must prove efficiency and skill on the simulator before their first interaction with a patient.