A novel predictor of ischemic complications in the treatment of ruptured middle cerebral artery aneurysms: Neck-branching angle

Objective

The risk factors of procedural cerebral ischemia (CI) in ruptured middle cerebral artery (MCA) aneurysms are unclear. This study proposed the neck-branching angle (NBA), a simple quantitative indicator of the aneurysm neck and branch vessels, and analyzed its usefulness as a predictor of procedural CI in ruptured MCA aneurysms.

Methods

We retrospectively analyzed 128 patients with ruptured saccular MCA aneurysms who underwent surgical or endovascular treatment between January 2014 and June 2021. We defined the NBA as the angle formed by the MCA aneurysm neck and M2 superior or inferior branch vessel line. The superior and inferior NBA were measured on admission via three-dimensional computed tomography angiography on admission. We divided the patients into clipping (106 patients) and coiling (22 patients) groups according to the treatment. Risk factors associated with procedural CI were analyzed in each group.

Results

Both groups showed that an enlarged superior NBA was a significant risk factor for procedural CI (clipping, P < 0.0005; coiling group, P = 0.007). The receiver operating characteristic curve showed the closed thresholds of the superior NBA with procedural CI in both groups (clipping group, 128.5°, sensitivity and specificity of 0.667 and 0.848, respectively; coiling group, 130.9°, sensitivity and specificity of 1 and 0.889, respectively).

Conclusion

The NBA can estimate the procedural risk of ruptured MCA aneurysms. In addition, an enlarged superior NBA is a risk factor for procedural CI in both clipping and coiling techniques.

Combining Machine-Measured Morphometric, Geometric, and Hemodynamic Factors to Predict the Risk of Aneurysm Rupture at the Middle Cerebral Artery Bifurcation

BACKGROUND

Middle Cerebral Artery Bifurcation Aneurysm (MbifA) is associated with a high risk of rupture and poor overall prognosis in patients once it ruptures. Morphological, geometric, and hemodynamic parameters have been identified as factors contributing to the rupture of intracranial aneurysms. However, there are no studies that combine these 3 types of parameters to specifically target MbifA rupture.

METHODS

This study enrolled all patients with MbifAs diagnosed at our treatment center from 1 April 2021 to 31 July 2023 who met the study criteria. All patients underwent digital subtraction angiography examination to obtain 3D rotational angiography data. We imported the complete image data into the Aneurysm/Artery Reconstruction and Analysis machine to obtain 13 morphological parameters (Dneck, Ddome, Height, Dmax, Dartery, aspect ratio [AR], size ratio, dome-neck-ratio [DNR], height-artery-ratio, bottleneck factor, Inflow Angle, Incline Angle, Arterial Angle), 5 geometric parameters (V,S,undulation index [UI], ellipticity index [EI],nonsphericity index [NSI]), and 5 hemodynamic parameters (wall shear stress [WSS], the maximum WSS, the parent artery WSS, the normalized WSS [NWSS], oscillatory shear index [OSI]). All the above significant parameters were tested by univariate and multivariate analyses to find out the independent discriminatory factors.

RESULTS

A total of 49 MbifAs (16 ruptured and 33 unruptured) from 44 patients were included in the study. Height (P = 0.033), AR (P = 0.007), DNR (P = 0.011), EI (P = 0.042), NSI(P = 0.030), UI(P = 0.027), WSS(P = 0.033), and NWSS(P = 0.002) were all associated with MbifA rupture in univariate analyses, but only NWSS was an independent risk factor (P = 0.036, OR = 0.046, 95% CI: 0.003-0.815) in multivariate logistic regression analysis.

CONCLUSIONS

Height, AR, DNR, EI, UI, NSI, WSS, and NWSS may be correlated with MbifA rupture, but only NWSS was an independent risk factor. A lower NWSS was associated with a higher risk of MbifA rupture. No significant differences were observed in the angle parameters, including the Inflow Angle, between ruptured and unruptured MbifAs. OSI was significantly increased at the dome of the aneurysm but the mean OSI was not found to be associated with MbifA rupture.

Surgical repair of torn base of ruptured middle cerebral artery trifurcation aneurysm

BACKGROUND

Treating complex middle cerebral artery (MCA) trifurcation aneurysms requires a delicate balance between achieving aneurysm obliteration and preserving vascular integrity. Various cerebral revascularization techniques, including bypass, and clip reconstruction are considered individually or in combination.

METHODS

This case report outlines a successful repair of a ruptured neck and base of MCA trifurcation aneurysm using a suturing-clip reconstruction technique. Temporary aneurysm trapping was implemented, with maintained elevated blood pressure to ensure collateral perfusion during repair of ruptured base and neck of MCA aneurysm.

CONCLUSION

The suturing-clip reconstruction exhibited long-term radiological stability, emerging as a valuable alternative for managing challenging MCA trifurcation aneurysms.

Three-Dimensional Morphometric Analysis of Anterior Cerebral Circulation Aneurysms

This article assesses the association between anterior circulation morphometry and the presence of intracranial aneurysm using three-dimensional rotational angiography (3DRA). A retrospective analysis at a Peruvian academic medical center between December 2018 and February 2020 identified 206 patients with unruptured intracranial aneurysms and matched controls who underwent 3DRA. Angiographic images were obtained per standard of care, and measurements of the vasculature were performed using 3DRA vascular automated software. A total of 163 aneurysms and 43 control angiograms were evaluated. Women represented 82.5% of the cases and the mean age was 55.9 years (standard deviation ± 14.2). In multivariate analysis, five specific features were found to be statistically significant predictors for presence of an anterior circulation aneurysm: female sex (odds ratio [OR] = 2.71; p  = 0.048), C-shape of the middle cerebral artery (MCA) (OR = 2.73; p  = 0.018), distal internal carotid artery (ICA) diameter (OR = 3.42; p  = 0.012), ICA bifurcation angle (OR = 1.02; p  = 0.036), and length of the carotid siphon (OR = 1.08; p  = 0.047). Features detected on 3DRA suggest morphological characteristics of the ICA and MCA may be predictive for intracranial aneurysm. Our findings build from prior reports by demonstrating five specific patient and imaging features associated with anterior circulation aneurysms. While 3DRA is the standard of care in many settings, medical centers with resource limitations may not have access to this technique. The demographic and morphological features identified in our study may have correlates that if detected on contrast computed tomography or magnetic resonance imaging studies, may be used to help screen for a higher level of care in select patients.

Acute evacuation of 54 intracerebral hematomas (aICH) during the microsurgical clipping of a ruptured middle cerebral artery bifurcation aneurysm-illustration of the individual clinical courses and outcomes with a serial brain CT/MRI panel until 12 months

PURPOSE

In aneurysmal intracerebral hemorrhage (aICH), our review showed the lack of the patient's individual (i) timeline panels and (ii) serial brain CT/MRI slice panels through the aICH evacuation and neurointensive care until the final brain tissue outcome.

METHODS

Our retrospective cohort consists of 54 consecutive aICH patients from a defined population who acutely underwent the clipping of a middle cerebral artery bifurcation saccular aneurysm (Mbif sIA) with the aICH evacuation at Kuopio University Hospital (KUH) from 2010 to 2019. We constructed the patient's individual timeline panels since the emergency call and serial brain CT/MRI slice panels through the aICH evacuation and neurointensive care until the final brain tissue outcome. The patients were indicated by numbers (1.-54.) in the pseudonymized panels, tables, results, and discussion.

RESULTS

The aICH volumes on KUH admission (median 46 cm3) plotted against the time from the emergency call to the evacuation (median 8 hours) associated significantly with the rebleeds (n=25) and the deaths (n=12). The serial CT/MRI slice panels illustrated the aICHs, intraventricular hemorrhages (aIVHs), residuals after the aICH evacuations, perihematomal edema (PHE), delayed cerebral injury (DCI), and in the 42 survivors, the clinical outcome (mRS) and the brain tissue outcome.

CONCLUSIONS

Regarding aICH evacuations, serial brain CT/MRI panels present more information than words, figures, and graphs. Re-bleeds associated with larger aICH volumes and worse outcomes. Swift logistics until the sIA occlusion with aICH evacuation is required, also in duty hours and weekends. Intraoperative CT is needed to illustrate the degree of aICH evacuation. PHE may evoke uncontrollable intracranial pressure (ICP) in spite of the acute aICH volume reduction.

Endovascular treatment of middle cerebral artery aneurysms: current status and future prospects

Middle cerebral artery (MCA) aneurysms are complex and widely distributed throughout the course of the MCA. Various types of aneurysms can occur in the MCA. Ruptured as well as unruptured MCA aneurysms may require treatment to avoid bleeding or rebleeding. Currently, clipping is regarded as the first-line choice for the treatment of MCA aneurysms. However, endovascular treatment (EVT) is emerging as an alternative treatment in selected cases. EVT techniques vary. Therefore, it is necessary to review EVT for MCA aneurysms. In this review, the following issues were discussed: MCA anatomy and anomalies, classifications of MCA aneurysms, the natural history of MCA aneurysms, EVT status and principle, deployments of traditional coiling techniques and flow diverters (FDs), and deployments and prospects of intrasaccular flow disruptors and stent-like devices. According to the review and our experience, traditional coiling EVT is still the preferred therapy for most MCA aneurysms. FD deployment can be used in selective MCA aneurysms. Parent artery occlusion (PAO) can be used to treat distal MCA aneurysms. In addition, new devices can be used to treat MCA aneurysms, such as intrasaccular flow disruptors and stent-like devices. In general, EVT is gaining popularity as an alternative treatment option; however, there is still a lack of evidence regarding EVT, and longer-term data are not currently available for most EVT devices.

Long-term outcomes of surgical clipping of saccular middle cerebral artery aneurysms: a consecutive series of 92 patients

Despite advances in endovascular treatment, microsurgical clipping of middle cerebral artery (MCA) aneurysms remains appropriate. We review the high occlusion rate and treatment durability seen with surgical clipping of MCA aneurysms. We retrospectively reviewed patients who underwent microsurgical clipping of saccular MCA aneurysms by a single surgeon. Outcomes included aneurysm occlusion rate and durability, modified Rankin scale (mRS), and postoperative neurological morbidities. Ninety-two patients with 92 saccular MCA aneurysms were included, 50% of which were ruptured aneurysms. The mean follow-up period was 59 months. Complete aneurysm occlusion was achieved in all except one patient (99%) with near-complete occlusion. MCA aneurysm clipping was durable, with only one patient (1%) requiring retreatment after 4 years due to regrowth. Of the cohort, 79.3% achieved mRS 0-2 at last follow-up, including all with unruptured aneurysms. Poor outcome at discharge was associated with age > 65 (p = .03), postoperative neurological morbidities (p = .006), and aneurysm rupture (p < .001). Older age remained the single correlate for poor long-term outcome (p = .04). For ruptured aneurysms, predictors of poor long-term outcome included hemiparesis on presentation (p = .017), clinical vasospasm requiring treatment (p = .026), and infarction related to vasospasm (p = .041). Older age (p = .046) and complex anatomy (p = .036) were predictors of new postoperative neurological morbidities in the unruptured group. MCA aneurysm clipping is safe, durable, and should be considered first-line treatment for patients with saccular MCA aneurysms, especially in centers with abundant surgical experience.

A deep-learning method for the end-to-end prediction of intracranial aneurysm rupture risk

It is critical to accurately predict the rupture risk of an intracranial aneurysm (IA) for timely and appropriate treatment because the fatality rate after rupture is 50 % . Existing methods relying on morphological features (e.g., height-width ratio) measured manually by neuroradiologists are labor intensive and have limited use for risk assessment. Therefore, we propose an end-to-end deep-learning method, called TransIAR net, to automatically learn the morphological features from 3D computed tomography angiography (CTA) data and accurately predict the status of IA rupture. We devise a multiscale 3D convolutional neural network (CNN) to extract the structural patterns of the IA and its neighborhood with a dual branch of shared network structures. Moreover, we learn the spatial dependence within the IA neighborhood with a transformer encoder. Our experiments demonstrated that the features learned by TransIAR are more effective and robust than handcrafted features, resulting in a 10 % - 15 % improvement in the accuracy of rupture status prediction.

An Analysis of Landmark Articles Regarding Aneurysms of the Middle Cerebral Artery

OBJECTIVE

Aneurysms located on the middle cerebral artery (MCA) range from 22% to 31.5% in prevalence of all aneurysms in the anterior cerebral circulation. This bibliometric analysis summarizes the most cited articles on MCA aneurysms and highlights the landmark publications that contributed to evidence-based practice.

METHODS

In the execution of this bibliometric-based review article, the Scopus database was used to perform a title-specific, keyword-based search for all publications until August 2022. The keyword "(middle cerebral artery OR MCA) AND aneurysm" was used. Our results were arranged in descending order based on the citation count of the article. The 100 most cited articles were selected for analysis. Parameters included the following: title, citation count, citations per year, authors, specialty of first author, institution, country of origin, publishing journal, Source Normalized Impact per Paper, and Hirsch index.

RESULTS

The keyword-based search showed that 1206 articles on MCA aneurysms were published up to August 2022. The top 100 articles were published between 1940 and 2019. The top 100 most cited articles collected a total of 6232 citations with an average of 62.3 citations per article. The rate of self-citations accounted for an average of 5.75% of the total number of citations.

CONCLUSIONS

The bibliometric analysis provides a quantitative overview of how medical literature and interventions are analyzed in academic medicine. In the present study, we evaluated the global trends in research regarding MCA aneurysms by finding the top 100 most cited articles.

Pipeline embolization of MCA aneurysms in the M2-M4 segment: Dual center study and meta-analysis

OBJECTIVE

Flow diversion of distal MCA aneurysms in the M2-M4 segments with Pipeline embolization device is promising, but further study is needed. Here, we seek to quantify the safety and efficacy of Pipeline embolization in the M2-M4 region in a dual-center cohort and comprehensive meta-analysis.

METHODS

Clinical and angiographic data of eligible patients was obtained from participating centers. A systematic review was performed with searches of Pubmed, Scopus, Embase, and the Cochrane Library for articles from inception to May 2021. 86 studies were identified in systematic review. Of these, 7 studies with 46 aneurysms met the inclusion criteria and were aggregated with 8 aneurysms from our dual-center cohort for analysis.

RESULTS

In our dual-center cohort, complete occlusion was observed in 88% (7/8) of aneurysms, and no patients experienced hemorrhagic or thromboembolic complications. Clinical outcomes were reported for 100% (54/54) of aneurysms included in meta-analysis and angiographic follow-up was available for 91% (49/54). The overall rate of complete aneurysm occlusion was 80% (95% CI, 69-91%), and the overall rate of clinical complication was 9% (95% CI, 2-16%).

CONCLUSION

Pipeline embolization of cerebral aneurysms of the M2-M4 segments of the MCA was reasonably effective and safe in a small group of selected patients, but further study is needed to validate these preliminary results.

Partially thrombosed middle cerebral artery-lenticulostriate artery aneurysm with native radiological examinations suggesting proximal lenticulostriate artery aneurysm: A case report

Background:

Preservation of the lenticulostriate artery (LSA) is crucial. LSAs usually cannot be spared with LSA aneurysms, when surgical clipping/excision or endovascular embolization of the LSA itself is performed. On the other hand, the LSA should be separated and preserved for proximal middle cerebral artery (M1)-LSA aneurysms.

Case Description:

We report a case of M1-LSA aneurysm with native radiological examinations suggesting LSA aneurysm. The highlight of this unusual case was that during surgery, the aneurysm orifice was almost covered with thrombus and blood flow in an aneurysm that appeared separate from M1. Partial thrombectomy-clip reconstruction was performed, and M1 and LSAs were well preserved.

Conclusion:

Even with currently developed radiological modalities, thrombosed intracranial aneurysms may be misdiagnosed, depending on intraluminal flow conditions. Intraoperative findings from craniotomy sometimes contribute to a better understanding of the pathophysiology and decisions on appropriate treatment strategy.

Massive intracerebral hemorrhages due to peripheral middle cerebral artery aneurysm rupture: A case report with a surgical video

Background

Saccular aneurysm in the distal segment of the middle cerebral artery (DMCA) occurs very rarely and often represents with a rupture. We report a successful surgical case of a DMCA aneurysm rupture with large cerebral and subarachnoid hemorrhage.

Case Description

A 44-year-old female presented a sudden onset headache and coma (the Glasgow Coma Scale was 3). Head computed tomography (CT) revealed a subarachnoid hemorrhage around the right Sylvian fissure and large intracranial hematoma in the right parietal lobe. The CT angiography showed a saccular aneurysm in the peripheral cortical segment of the right angular branch of the right DMCA. We decided to perform a right craniotomy to evacuate hematoma and interrupt the aneurysm. Just after the dural incision, the aneurysm ruptured again. We applied a temporary clip on the artery proximal to the aneurysm before excising it.

Conclusion

Aneurysm in DMCA can be treated safely with surgical excision and risk of sudden recurrent hemorrhage needs to be anticipated.

Distance and force visualisations for improved simulation of intracranial aneurysm clipping

Purpose

The treatment of cerebral aneurysms shifted from microsurgical to endovascular therapy. But for some difficult aneurysm configurations, e.g. wide neck aneurysms, microsurgical clipping is better suited. From this combination of limited interventions and the complexity of these cases, the need for improved training possibilities for young neurosurgeons arises.

Method

We designed and implemented a clipping simulation that requires only a monoscopic display, mouse and keyboard. After a virtual craniotomy, the user can apply a clip at the aneurysm which is deformed based on a mass–spring model. Additionally, concepts for visualising distances as well as force were implemented. The distance visualisations aim to enhance spatial relations, improving the navigation of the clip. The force visualisations display the force acting on the vessel surface by the applied clip. The developed concepts include colour maps and visualisations based on rays, single objects and glyphs.

Results

The concepts were quantitatively evaluated via an online survey and qualitatively evaluated by a neurosurgeon. Regarding force visualisations, a colour map is the most appropriate concept. The necessity of distance visualisations became apparent, as the expert was unable to estimate distances and to properly navigate the clip. The distance rays were the only concept supporting the navigation appropriately.

Conclusion

The easily accessible surgical training simulation for aneurysm clipping benefits from a visualisation of distances and simulated forces.

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.

Ruptured giant aneurysm of a cortical middle cerebral artery: A case report

Background

Aneurysms of the cortical branches of the middle cerebral artery (MCA) are rare. They usually are secondary to traumatic or infectious etiologies and are rarely idiopathic. The specific characteristics of idiopathic aneurysms in such location are not well defined in the literature. The authors report a rare case of a ruptured giant idiopathic cortical MCA aneurysm with review of the available literature on this clinical entity.

Case Description

A 24-year-old female presented with headache, disturbed level of consciousness, and right-sided weakness. Imaging studies showed a left frontoparietal intracerebral hematoma and a giant saccular aneurysm in the posterior parietal cortical branch of the MCA. The patient had no history of head trauma or active infection; therefore, the aneurysm was considered idiopathic. A microsurgical clipping of the aneurysm with evacuation of the hematoma was performed. There were no surgical complications, and the patient achieved a good outcome modified Rankin Scale of 1 with no neurological deficits.

Conclusion

Idiopathic aneurysms of the cortical branches of the MCA are rare, and usually present with intraparenchymal hemorrhage due to rupture. There is no clear consensus regarding the optimal management strategy. This case shows that timely management can lead to good outcomes.

Clinical features of ischemic complications after unruptured middle cerebral artery aneurysm clipping: patients and radiologically related factors

Postoperative ischemic complication results in neurological sequelae and longer hospitalization after unruptured middle cerebral artery (MCA) aneurysm clipping surgery. We evaluated the radiological and patient-related factors associated with ischemic complications after unruptured MCA aneurysm clipping surgery. Patient demographics, radiological findings, and intraoperative factors were compared between patients with and without postoperative ischemic complications. The clinical courses and outcomes of postoperative ischemic complications were compared according to the types of ischemic complication. Forty-two out of 2227 patients (1.9%) developed postoperative ischemic complications after MCA aneurysm clipping. Multivariate analysis revealed that diabetes mellitus (DM) was a patient-related factor. Intraarterial (IA) calcification of the distal internal carotid artery (ICA), preoperative M1 stenosis, and M1 aneurysm were radiological factors that increased the risk of postoperative ischemic complications. DM was significantly associated with divisional branch territory infarction (P = 0.04). The time to first presentation of ischemic complication was significantly longer in divisional branch territory infarction than perforator territory infarction (67.8 ± 75.9 h vs. 22 ± 20.7, P = 0.023). Twelve out of 42 patients with ischemic complications (28.6%) had unfavorable outcome (mRS > 3). Perforator territory infarction was significantly associated with an unfavorable outcome (mRS > 3, P = 0.019). IA calcification of the distal ICA, M1 stenosis and aneurysms, and DM were significantly associated with postoperative ischemic complications after unruptured MCA aneurysm clipping. Patients with DM should be closely monitored postoperatively to detect delayed occurrence of divisional branch infarction. Trial registration number: 2019-1002, Date of registration: January 1, 2005, "retrospectively registered".

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.

Endovascular coil embolization of proximal middle cerebral artery aneurysms has better outcomes than other middle cerebral artery aneurysms: A retrospective study

Purpose

Although some authors proposed that coil embolization in middle cerebral artery (MCA) aneurysms is a useful and effective alternative, the characteristics of the aneurysms may be different at each location. We compared the results of coil embolization of proximal middle cerebral artery aneurysms with those of other middle cerebral artery aneurysms.

Methods

Data from 46 patients with 50 aneurysms were retrospectively evaluated. We defined the aneurysms inside of the insular cortex as proximal MCA (pMCA) aneurysms and those outside of the insular cortex as non-proximal MCA (npMCA) aneurysms. The results of the occlusion were divided into classes 1, 2, and 3 of the Raymond scale. We collected the results of the occlusion from the operative notes supplied by a neuroendovascular specialist.

Results

Univariate analysis identified favorable results for pMCA aneurysms (class 1: pMCA = 22 npMCA = 11; P < 0.01). In the radiological follow-up results, we achieved class 1 in 29 patients (69%; pMCA = 21 and npMCA = 8; P < 0.01). Side wall type aneurysms (pMCA = 14, npMCA = 2; P < 0.01) and the number of branches from the neck of ≤1 (pMCA = 14, npMCA = 2; P < 0.01) were significantly recognized at the pMCA.

Conclusions

Proximal middle cerebral artery aneurysm clipping is difficult because the origin of the lenticulostriate arteries is often hidden behind the aneurysmal dome. In the present study, endovascular coil embolization for pMCA aneurysms obtained better results than that for npMCA aneurysms because of the morphological characteristics. Endovascular coil embolization seems to be efficacious for pMCA aneurysms as compared with npMCA aneurysms.

Internal maxillary artery bypass for the treatment of complex middle cerebral artery aneurysms

OBJECTIVEThe rapid innovation of the endovascular armamentarium results in a decreased number of indications for a classic surgical approach. However, a middle cerebral artery (MCA) aneurysm remains the best example of one for which results have favored microsurgery over endovascular intervention. In this study, the authors aimed to evaluate the experience and efficacy regarding surgical outcomes after applying internal maxillary artery (IMA) bypass for complex MCA aneurysms (CMCAAs).METHODSAll IMA bypasses performed between January 2010 and July 2018 in a single-center, single-surgeon practice were screened.RESULTSIn total, 12 patients (9 males, 3 females) with CMCAAs managed by high-flow IMA bypass were identified. The mean size of CMCAAs was 23.7 mm (range 10-37 mm), and the patients had a mean age of 31.7 years (range 14-56 years). The aneurysms were proximally occluded in 8 cases, completely trapped in 3 cases, and completely resected in 1 case. The radial artery was used as the graft vessel in all cases. At discharge, the graft patency rate was 83.3% (n = 10), and all aneurysms were completely eliminated (83.3%, n = 10) or greatly diminished (16.7%, n = 2) from the circulation. Postoperative ischemia was detected in 2 patients as a result of graft occlusion, and 1 patient presenting with subarachnoid hemorrhage achieved improved modified Rankin Scale scores compared to the preoperative status but retained some neurological deficits. Therefore, neurological assessment at discharge showed that 9 of the 12 patients experienced unremarkable outcomes. The mean interval time from bypass to angiographic and clinical follow-up was 28.7 months (range 2-74 months) and 53.1 months (range 19-82 months), respectively. Although 2 grafts remained occluded, all aneurysms were isolated from the circulation, and no patient had an unfavorable outcome.CONCLUSIONSThe satisfactory result in the present study demonstrated that IMA bypass is a promising method for the treatment of CMCAAs and should be maintained in the neurosurgical armamentarium. However, cases with intraoperative radical resection or inappropriate bypass recipient selection such as aneurysmal wall should be meticulously chosen with respect to the subtype of MCA aneurysm.

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.

The role of the Sylvian fissure configuration and the vascular anatomy on different bleeding patterns in ruptured middle cerebral artery aneurysms

OBJECTIVE

Ruptured middle cerebral artery (MCA) aneurysms are one of the causes of subarachnoid (SAH) or intracerebral hemorrhage (ICH) but the factors associated with the bleeding type are unknown. The aim of the study was to analyze the association of the morphological variations of the Sylvian fissure (SF) and vascular parameters on occurrence of different bleeding patterns in patients with ruptured MCA aneurysms.

PATIENTS AND METHODS

The data of consecutive 202 patients with ruptured MCA aneurysm of two centers were included for analysis. Patients were divided into three groups: Group 1 with SAH, Group 2 with accompanying ICH and Group 3 with intrasylvian hemorrhage (ISH). The SF was divided into five types according to the previously described classification. Analyzed vascular parameters were aneurysm size, localization, presence of a daughter aneurysm, shape, and angulation of the aneurysm sac.

RESULTS

A total of 202 patients (141 female, 61 male, mean age 52.4 yr) were included in this study. 67 patients (33.2%) had a SAH, 122 (60.4%) an ICH and 13 (6.4%) presented with ISH. Statistical analysis showed a significant association of narrow and twisted SF types 4 and 5 (p < 0.001) and temporal angulation of the aneurysm (p = 0.030) for occurrence of ICH. All other vascular parameters showed no significant association for any kind of hemorrhage.

CONCLUSION

Our results allow the conclusion that the complex SF types 4 and 5, as well as the temporal angulation of the aneurysm sac are associated with the occurrence of ICH in ruptured MCA aneurysms.

Treatment of Unruptured Distal Anterior Circulation Aneurysms with Flow-Diverter Stents: A Meta-Analysis

BACKGROUND

The safety and efficacy of flow diversion among distal anterior circulation aneurysms must be proved.

PURPOSE

Our aim was to analyze the outcomes after flow diversion among MCA, anterior communicating artery, and distal anterior cerebral artery aneurysms.

DATA SOURCES

A systematic search of 3 databases was performed for studies published from 2005 to 2018.

STUDY SELECTION

According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we included studies reporting flow diversion of distal anterior circulation aneurysms.

DATA ANALYSIS

Random-effects meta-analysis was used to pool aneurysm occlusion and complication rates. From the individual patient data, univariate and multivariate analyses were used to test predictors of occlusion and complications.

DATA SYNTHESIS

We included 27 studies (484 aneurysms). The long-term adequate occlusion rate (O'Kelly-Marotta scale, C-D) was 82.7% (295/364; 95% CI, 77.4%-87.9%; I² = 52%). Treatment-related complications were 12.5% (63/410; 95% CI, 9%-16%%; I² = 18.8%), with 5.4% (29/418; 95% CI, 3.2%-7.5%; I² = 0%) morbidity. MCA location was an independent factor associated with lower occlusion (OR = 0.5, P = .03) and higher complication rates (OR = 1.8, P = .02), compared with anterior communicating artery and distal anterior cerebral artery aneurysms. The Pipeline Embolization Device (versus other stents) gave better occlusion rates (OR = 2.6, P = .002), whereas large/giant aneurysms were associated with higher odds of complications (OR = 2.2, P = .03). The rates of occlusion and narrowing of arteries covered by flow-diverter stents were 6.3% (29/283; 95% CI, 3.5%-9.1%; I² = 4.2%) and 23.8% (69/283; 95% CI, 15.7%-32%; I² = 80%), respectively. Symptoms related to occlusion and narrowing of the jailed arteries were 3.5% (6/269; 95% CI, 1.1%-5%; I² = 0%) and 3% (6/245; 95% CI, 1%-4%; I² = 0%), respectively.

LIMITATIONS

We reviewed small and retrospective series.

CONCLUSIONS

Flow diversion among distal anterior circulation aneurysms is effective, leading to adequate aneurysm occlusion in 83% of cases. However, this strategy has some limitations among MCA and larger lesions, especially related to the higher rate of complications. Compared with the other devices, the Pipeline Embolization Device seems to be associated with a higher occlusion rate.

Comparison of Supraorbital and Pterional Keyhole Approach for Clipping Middle Cerebral Artery Aneurysm: A Chinese Population-Based Study

OBJECTIVE

Keyhole craniotomy is a minimally invasive approach for the treatment of middle cerebral artery (MCA) aneurysms. The aim of this study was to compare the clinical outcome between supraorbital keyhole approach and pterional keyhole approach (PKA) in Chinese patients with MCA aneurysm.

METHODS

Consecutive patients with MCA aneurysms were reviewed between January 2013 and December 2017. Efficacy and safety between PKA and supraorbital keyhole approach were compared. Poor outcome was defined as modified Rankin Scale score of 3-6 at discharge.

RESULTS

This study enrolled 260 patients; 222 (85.4%) had ruptured aneurysm, and 183 (70.4%) received PKA. The distribution of PKA in unruptured and ruptured aneurysms showed no significant difference (P > 0.05). In subgroup analyses, PKA was more likely associated with poor outcome at discharge in patients with unruptured aneurysms (odds ratio = 5.500, 95% confidence interval = 1.013-29.850, P = 0.048), whereas approach selection was not an independent factor predicting poor outcome in patients with ruptured aneurysms (P > 0.05).

CONCLUSIONS

In a Chinese population, supraorbital keyhole approach was superior to PKA in improving outcome in patients with unruptured MCA aneurysms, but the 2 approaches showed comparable outcomes at discharge in patients with ruptured aneurysms.

Middle Cerebral Artery Aneurysm "Neck Overhang": Decreased Postclipping Residual Using the Intersecting Clipping Technique

BACKGROUND

Middle cerebral artery (MCA) aneurysms continue to be viewed by many as primarily surgical entities.

OBJECTIVE

To introduce a new, easily measurable dimension termed "neck overhang," defined as the amount of the aneurysm that extends proximal to the 2 dimensionally defined "neck" and to evaluate the utility of the intersecting clipping technique (use of straight clip and intersecting fenestrated clip) to adapt to this overhanging segment's specific dimensions and achieve better obliteration of the MCA aneurysms.

METHODS

We reviewed retrospectively 100 MCA aneurysms treated surgically over the last 10 yr at our institution. We identified the clipping technique that was performed (intersecting vs "standard" technique) and we evaluated the presence of a postoperative remnant. We then correlated these with the aneurysm's overhanging neck length.

RESULTS

Forty-three aneurysms were treated with the intersecting clipping technique. The overall rate of remnant was 16%. In the standard group, the rate of remnant was 23%, whereas with intersecting clipping that was 7% (P = .029). Within the standard clipping group, we found that the optimum threshold for length of the neck overhang was ≥1.9 mm in order to predict the occurrence of residual. Applying this threshold to the intersecting clipping technique group resulted in a reduction in remnant from 35% in the standard group to 9%.

CONCLUSION

Neck overhang >1.9 mm is associated with a higher chance of postclipping residual aneurysm in MCA aneurysms. The intersecting clipping technique is a versatile technique that can conform to various aneurysms' geometry and can reduce the rate of post clipping residual for aneurysms with high neck overhang.

Semi-automatic measurements and description of the geometry of vascular tree based on Bézier spline curves: application to cerebral arteries

Background

The geometry of the vessels is easy to assess in novel 3D studies. It has significant influence on flow patterns and this way the evolution of vascular pathologies such as aneurysms and atherosclerosis. It is essential to develop robust system for vascular anatomy measurement and digital description allowing for assessment of big numbers of vessels.

Methods

A semiautomatic, robust, integrated method for vascular anatomy measurements and mathematical description are presented. Bezier splines of 6th degree and continuity of C3 was proposed and distribution of control points was dependent on local radius. Due to main interest of our institution, the system was primarily used for the assessment of the geometry of the intracranial arteries, especially the first Medial Cerebral Artery division.

Results

1359 synthetic figures were generated: 381 torus and 978 spirals. Experimental verification of the proposed methodology was conducted on 400 Middle Cerebral Artery divisions.

Conclusions

In difference to other described solution all proposed methodology steps were integrated allows analysis of variability of geometrical parameters among big number of Medial Cerebral Artery bifurcations using single application. This allows for determination of significant trends in the parameters variability with age and in contrary almost no differences between men and women.

Usefulness of Intraoperative Imaging in a Patient with a Ruptured Aneurysm of the M4 Segment of the Middle Cerebral Artery

BACKGROUND

Treating cerebral aneurysms in the M4 segment of the middle cerebral artery (MCA) is challenging because they are small and are buried in the brain parenchyma.

CASE DESCRIPTION

A right-handed Asian woman in her 80s was referred to our hospital with a chief complaint of altered level of consciousness. On admission, her consciousness level on the Glasgow Coma Scale was 7 (E1V1M5), and a computed tomography (CT) scan showed subarachnoid hemorrhage with intracerebral hematoma in the left temporal lobe. Subsequent 3-dimensional CT angiography showed an aneurysm in the M4 segment of the left MCA. The aneurysm of the patient was clipped safely and effectively because of the navigation system in combination with intraoperative angiography. The navigation system was especially useful for estimating the proximal part of the parent artery at the brain surface, whereas intraoperative angiography was especially useful for confirming that the proximal portion of the parent artery identified by the navigation system was correct.

CONCLUSIONS

We emphasize the importance of choosing the modality of intraoperative imaging according to each characteristic when treating M4 segment aneurysms.

Middle cerebral artery extension and the risk for aneurysmal disease

The intracranial artery aneurysm is an abnormal dilatation at the wall and the most serious complication is its rupture that is associated with high rates of neurological mortality and morbidity. Its most common location in arterial bifurcations suggests that the hemodynamic of blood flow plays a key role, but the effect of the length of the M1 segment of the middle cerebral artery is poorly explored. We analyzed biplanar brain angiograms to measure the extent of the M1 segment and its relationship to the presence of aneurysm at the bifurcation. Of 475 patients, a total of 682 bilateral measurements were analyzed. Women accounted for 58.7% and the mean age was 50.2 ± 15.5. Aneurysms were detected in 45 arteries, about the average length of the M1 artery; the right segment measure (2.98 ± 0.99 cm) was statistically lesser than the left (3.09 ± 1.38 cm). Applying the regression coefficient, arteries with aneurysm have an average length of 0.419 cm smaller than an artery without aneurysm, and this difference was statistically significant (p < 0.05). Though the wall shear stress component is a proven risk factor for the development of aneurysms in bifurcations, a smaller extension of the M1 segment may also be implicated in its development.

Morphological and Hemodynamic Differences Between Aneurysmal Middle Cerebral Artery Bifurcation and Contralateral Nonaneurysmal Anatomy

BACKGROUND

The morphological and hemodynamic features differ between middle cerebral artery (MCA) bifurcations with and without aneurysms.

OBJECTIVE

To investigate the morphological and hemodynamic differences between aneurysmal MCA bifurcation and contralateral nonaneurysmal anatomy.

METHODS

Computed tomography angiography of 36 patients with unilateral small saccular MCA bifurcation aneurysms was evaluated. The parent-daughter angles (φ1 for larger branch and φ2 for smaller branch), bifurcation angle (φ = φ1 + φ2), inclination angle (γ angle), and their relationships with the MCA bifurcation locations were analyzed. Computational fluid dynamics simulation was performed in 6 cases to explore the hemodynamics influenced by the bifurcation morphology.

RESULTS

The φ angle was significantly higher in aneurysmal than contralateral nonaneurysmal bifurcations (160.8° ± 31.0° vs 99.0° ± 19.2°, respectively; P = .000); the φ1, φ2, and γ angles were also higher. However, by regression analysis combined with MCA bifurcation locations, only the φ angle might be associated with the aneurysm presence (odds ratio = 1.120, 95% confidence interval = 1.059-1.185) and a φ angle cut-off of 124.8° was established. Computational fluid dynamics simulation demonstrated that flow resistance of the wider aneurysmal MCA bifurcation was significantly higher than that on the contralateral side.

CONCLUSION

A larger φ angle was more prevalent in aneurysmal than nonaneurysmal MCA bifurcations, and the higher flow resistance caused by the larger φ angle might be a potential hemodynamic factor associated with MCA aneurysm presence.

Treatment of Middle Cerebral Artery Aneurysms with Flow-Diverter Stents: A Systematic Review and Meta-Analysis

BACKGROUND

The safety and efficacy of flow-diversion treatment of MCA aneurysms have not been well-established.

PURPOSE

Our aim was to evaluate angiographic and clinical outcomes after flow diversions for MCA aneurysms.

DATA SOURCES

A systematic search of PubMed, MEDLINE, and Embase was performed for studies published from 2008 to May 2017.

STUDY SELECTION

According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we selected studies with >5 patients describing angiographic and clinical outcomes after flow-diversion treatment of MCA aneurysms.

DATA ANALYSIS

Random-effects meta-analysis was used to pool the following outcomes: aneurysm occlusion rate, procedure-related complications, rupture rate of treated aneurysms, and occlusion of the jailed branches.

DATA SYNTHESIS

Twelve studies evaluating 244 MCA aneurysms were included in this meta-analysis. Complete/near-complete occlusion was obtained in 78.7% (95% CI, 67.8%-89.7%) of aneurysms. The rupture rate of treated aneurysms during follow-up was 0.4% per aneurysm-year. The rate of treatment-related complications was 20.7% (95% CI, 14%-27.5%), and approximately 10% of complications were permanent. The mortality rate was close to 2%. Nearly 10% (95% CI, 4.7%-15.5%) of jailed arteries were occluded during follow-up, whereas 26% (95% CI, 14.4%-37.6%) had slow flow. Rates of symptoms related to occlusion and slow flow were close to 5%.

LIMITATIONS

Small and retrospective series could affect the strength of the reported results.

CONCLUSIONS

Given the not negligible rate of treatment-related complications, flow diversion for MCA aneurysms should be considered an alternative treatment when traditional treatment methods are not feasible. However, when performed in this select treatment group, high rates of aneurysm occlusion and protection against re-rupture can be achieved.

Cortical aneurysms of the middle cerebral artery: A review of the literature

Background:

Middle cerebral artery (MCA) aneurysms constitute from 18–40% of all intracranial aneurysms. They are mainly found in the proximal and bifurcation tracts and only in the 1.1-1.7% of cases they are located in the distal segment. The authors report a case of a ruptured saccular cortical MCA aneurysm with unknown etiology.

Case Description:

A 53-year-old female was admitted with a sudden severe headache, nausea, vomiting, and a slight left hemiparesis. The computed tomography (CT) scan showed subarachnoid hemorrhage (SAH) in the left sylvian fissure and intracerebral hemorrhage (ICH) in the left posterior parietal area. The CT angiography (CTA) reconstructed with 3D imaging showed a small saccular aneurysm in the M4 segment in proximity of the angular area. A left parieto-temporal craniotomy was performed, the aneurysm was clipped and the ICH evacuated. The motor deficit was progressively recovered. At 3-month follow-up examination, the patient was asymptomatic and feeling well.

Conclusions:

In our opinion, surgery is the best choice for the treatment of ruptured M4 aneurysms with ICH, because it allows to evacuate the hematoma and to exclude the aneurysm from the intracranial circulation. In addition, we suggest both the use of the neuronavigation technique and of the indocyanine green videoangiography (ICGV) for the aneurismal surgery.

Treatment of Large and Giant Middle Cerebral Artery Aneurysms: Risk Factors for Unfavorable Outcomes

OBJECTIVE

This study aimed to assess the clinical and radiologic outcomes after neurosurgical treatment of large and giant aneurysms of the middle cerebral artery (MCA). In addition, we aimed to identify risk factors for unfavorable outcomes.

METHODS

This retrospective study included 105 patients with 106 large or giant MCA aneurysms treated with neurosurgical methods, including microsurgery and endovascular treatment, over a 15-year period.

RESULTS

The mean aneurysm size was 15.3 ± 7.1 mm. Ten (9.4%) were giant aneurysms. The MCA bifurcation was the most common aneurysm site, followed by the MCA trunk and distal MCA. Aneurysm clipping was the most common treatment method, followed by clipping or trapping with bypass surgery and endovascular treatment. However, acute cerebral infarction was the most common complication (16.0%), poor outcomes (modified Rankin Scale score, 3-6) developed in 12.3% of aneurysms after treatment, and 6.6% of treated aneurysms needed retreatment. Multivariate analysis showed that independent risk factors for acute cerebral infarction after treatment were aneurysms located on the MCA trunk and 2 or more underlying diseases. Initial presentation with subarachnoid hemorrhage and complications during treatment were independent risk factors for poor outcomes. In addition, endosaccular coiling was an independent risk factor for retreatment.

CONCLUSIONS

Neurosurgical management should be considered a priority for large and giant MCA aneurysms because of the high rupture rate and clinical symptoms. However, treatment outcomes remain unsatisfactory. Therefore, tailored management with consideration of risk factors for unfavorable outcomes should be implemented.

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.

The Medina Embolic Device: early clinical experience from a single center

Objective

To report our initial experience with the Medina Embolic Device (MED) in unruptured intracranial aneurysms either as sole treatment or in conjunction with additional devices.

Methods

15 consecutive patients (6 women, 9 men) with unruptured aneurysms were treated between September 2015 and April 2016. The aneurysm fundus measured at least 5 mm. We evaluated the angiographic appearances of treated aneurysms at the end of the procedure and at follow-up, the clinical status, complications, and requirement for adjunctive devices.

Results

The MED was successfully deployed in all but one case and adjunctive devices were required in 10 cases. Aneurysm locations were middle cerebral artery bifurcation (n=3), internal carotid artery (ICA) bifurcation (n=1), supraclinoid ICA (n=5), posterior communicating artery (n=1), anterior communicating artery (n=2), cavernous ICA (n=2), distal basilar sidewall (n=1), basilar tip (n=1). Three patients had complications although none could be attributed to the MED. Immediate angiographic results were modified Raymond-Roy classification (mRRC) I=1, mRRC II=5, mRRC IIIa=3, mRRC IIIb=5, and one patient showed contrast stasis within the fundus of the aneurysm. Follow-up angiography was available in 11 patients, with four showing complete aneurysm exclusion, six with stable remnants and one patient with an enlarging neck remnant.

Conclusions

The MED represents a major step forward in the treatment of intracranial aneurysms. It can result in rapid exclusion of an aneurysm from the circulation and has a good safety profile. We believe that the true value of the MED will be in combining its use with adjunctive devices such as endoluminal flow diverters that will result in rapid aneurysmal exclusion.

Three-Dimensional Angiographic Evaluation of Middle Cerebral Artery Trunk Aneurysms: Demonstration of the Close Relationship Between the Early Frontal Cortical Branches and Lateral Lenticulostriate Arteries

BACKGROUND

For the treatment planning of a patient with a middle cerebral artery (MCA) trunk aneurysm, understanding the anatomic relationship among the aneurysm, branching vessels, and lenticulostriate arteries (LSAs) is important. We aimed to demonstrate the branching-vessel anatomy related to an MCA trunk aneurysm using 3-dimensional (3D) angiography.

METHODS

We retrospectively reviewed 3D angiographic findings of 64 cases of MCA trunk aneurysms using a 3D workstation with various postprocessing conditions. We classified the aneurysms into 4 groups (early frontal cortical branch [EFCB], early temporal cortical branch [ETCB], LSA, and nonbranching aneurysms) and analyzed the relationship between the branching vessels and the LSAs.

RESULTS

There were 30 EFCB aneurysms, 25 ETCB aneurysms, 7 LSA aneurysms, and 2 nonbranching aneurysms. Twenty-six (86.7%) of the 30 EFCB aneurysms shared common origins and were associated with the LSAs, but none of the 25 ETCB aneurysms were. Three of 24 patients who received clipping for an EFCB aneurysm experienced a postoperative infarction in the LSA territory. In these 3 patients, the LSA originated from the EFCB and was closely related with the aneurysm.

CONCLUSIONS

We have identified a clinically important anatomic relationship between the MCA trunk aneurysm and branching vessels, including the LSAs. EFCB aneurysms show a close relationship with the LSAs. Pretreatment identification of the origin of the LSAs is important to obviate any perforator injury in EFCB aneurysms.

Irregular Shape of Intracranial Aneurysm Indicates Rupture Risk Irrespective of Size in a Population-Based Cohort

BACKGROUND AND PURPOSE

Size and shape of saccular intracranial aneurysms (sIA) reflect the condition of the sIA wall and were risk factors for rupture in previous follow-up studies. We investigated how well size or shape identify rupture-prone sIAs.

METHODS

In a population-based registry, we investigated the characteristics of ruptured sIAs treated in a single neurosurgical center (1980-2014). In addition to univariate analysis, logistic regression was used in multivariate analysis, and sensitivity and specificity of size or shape were calculated using receiver operating characteristic curves.

RESULTS

Ruptured sIAs were on average larger than unruptured sIAs (median, 7 versus 4 mm; P<0.000), but location and patient background affected the size at rupture. Of the ruptured sIAs, 38% were smaller than 7 mm and 18% were smaller than 4 mm. Of those sIAs that had ruptured at a small (<7 mm) size, 87% had an irregular shape. In multivariate analysis, irregular shape had the strongest association with presentation as ruptured sIA (odds ratio, 7.1; 95% confidence interval, 6.0-8.3), with better sensitivity (91%) and specificity (76%), in contrast to smoking (odds ratio, 0.7; 95% confidence interval, 0.6-0.9; sensitivity, 28%; specificity 57%) and Population, Hypertension, Age, Size of sIA, Earlier SAH from another sIA, Site of sIA score (odds ratio, 1.5; 95% confidence interval, 1.4-1.6).

CONCLUSIONS

Irregular or multilobular shape is strongly associated with rupture in sIAs of all sizes and independent of location and patient background. Especially sIAs with irregular shape should be considered as high rupture risk lesions, even if small in diameter and in nonsmoking patients with low PHASES scores.

Contralateral Approach to Bilateral Middle Cerebral Artery Aneurysms: Comparative Study, Angiographic Analysis, and Surgical Results

BACKGROUND

Bilateral aneurysms located between the 2 middle cerebral artery (MCA) bifurcations may be approachable through a single unilateral approach.

OBJECTIVE

To identify anatomic parameters based on imaging that would favor a contralateral approach.

METHODS

From January 1998 to December 2013, we retrospectively identified 173 patients with bilateral intracranial aneurysms. Fifty-one patients had bilateral MCA aneurysms. A total of 38 patients underwent a single craniotomy with a contralateral microsurgical approach (group 1 or contralateral group) and 13 patients underwent bilateral craniotomies (group 2 or bilateral group). For both groups, we analyzed aneurysm characteristics, morphology, size, projections, and distance to the contralateral corridor, as well as surgical time, outcome, and postoperative complications.

RESULTS

All aneurysms approached contralaterally were unruptured and without wall calcifications. Of the contralaterally approached aneurysms, 97% were smaller than 14 mm. The median length of the contralateral A1 was 13.2 mm (range: 6-19.8 mm) and the median length of the contralateral M1 was 14.2 mm (range: 4.6-21 mm). The contralateral group had a good postoperative outcome (modified Rankin Scale 0-3) in 80% of ruptured cases and 86% of unruptured cases. The median surgical time was 120 minutes (range: 75-255 minutes), 43% shorter than the bilateral group.

CONCLUSION

The contralateral approach for bilateral MCA aneurysms in selected patients is feasible in experienced hands, with acceptable morbidity and mortality. The contralateral approach requires a meticulous preoperative analysis of the characteristics of the aneurysms to be clipped and of the anatomic constraints of the microsurgical operative corridor.

ABBREVIATIONS

A1, anterior cerebral artery proximal segmentbMCA, bilateral middle cerebral arteryCTA, computed tomographic angiographyHH, Hunt-Hess scaleIA, intracranial aneurysmsICA, internal carotid arteryICAbif, internal carotid artery bifurcationMCA, middle cerebral arteryM1, middle cerebral artery proximal segmentmRS, modified Rankin ScaleSAH, subarachnoid hemorrhage.

Results of re-exploration because of compromised distal blood flow after clipping unruptured intracranial aneurysms

BACKGROUND

One of the major causes for performing unplanned re-exploration of a craniotomy after microsurgery for unruptured intracranial aneurysms (UIAs) is compromised distal blood flow after clipping. Therefore, it is important to identify the causes of compromised distal blood flow after clipping and the factors that influence the prognosis for re-exploration in order to decrease ischemic complications related to clipping UIAs.

METHOD

Between January 2007 and December 2013, 1954 patients underwent microsurgery for UIAs. In this cohort, 20 patients (1.0%) required unplanned re-exploration of the craniotomy for several reasons, and 11 patients (0.6%) underwent unplanned re-exploration with clip repositioning or changing of the previous clip because of compromised distal blood flow after clipping. Patient characteristics, aneurysm properties, intraoperative findings, annual incidence and prognosis were analyzed in these 11 patients.

RESULTS

The annual incidence of re-exploration has gradually decreased since the introduction of several intraoperative monitoring techniques. In total, 3.0% of UIAs in the M1 trunk, 0.8% of UIAs at the origin of the anterior choroidal artery (AchA) and 0.5% of UIAs at the bifurcation of the middle cerebral artery (MCA) required re-exploration. Here, all 11 UIAs had broad necks, and atherosclerosis was identified around 10 UIAs. Six patients with compromised MCA flow demonstrated relatively better outcomes following re-exploration than five patients with a compromised lenticulostriate artery (LSA) or AchA flow. Four patients with delayed ischemic symptoms demonstrated relatively better outcomes than the seven patients who developed ischemic symptoms immediately postoperatively.

CONCLUSION

Clinicians need to be more careful not to compromise distal blood flow when clipping UIAs at the MCA and AchA origin. Various intraoperative monitoring techniques can help reduce the incidence of compromised distal blood flow after clipping.

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

BACKGROUND

The middle cerebral artery (MCA) is the most frequent location for unruptured intracranial aneurysms. Controversy remains as to which unruptured MCA aneurysms should be treated prophylactically.

OBJECTIVE

To identify independent topographical and morphological variables that could predict increased rupture risk of MCA aneurysms.

METHODS

A retrospective analysis of computed tomography angiography data of 1009 consecutive patients with 1309 MCA aneurysms, referred between 2000 and 2009 to Helsinki University Hospital, was carried out. Morphological and topographical parameters examined for MCA aneurysms comprised aneurysm wall regularity, size, neck width, aspect ratio, bottleneck factor, height-width ratio, location along the MCA, side, distance from the internal carotid artery bifurcation, and dome projection in axial and coronal computed tomography angiography views. Univariate and multivariate logistic regression analyses were performed to determine independent risk factors for rupture.

RESULTS

Of the 1309 MCA aneurysms, 69% were unruptured and 31% were ruptured. Most unruptured MCA aneurysms were smaller than 7 mm (78%), with a smooth wall (80%) and a height-width ratio of 1 (47%) and were located at the main bifurcation (57%). Ruptured MCA aneurysms, mostly 7 to 14 mm in size (55%), had an irregular wall (78%) and a height-width ratio greater than 1 (72%) and were located at the main bifurcation (77%). Thirty-eight percent of MCA bifurcation aneurysms, 74% of large aneurysms, 64% of aneurysms with an irregular wall, and 49% of aneurysms with a height-width ratio greater than 1 were ruptured.

CONCLUSION

Location at the main MCA bifurcation, wall irregularity, and less spherical geometry were independently associated with rupture of MCA aneurysms with a correlation with aneurysm size. artery.

Focused opening of the sylvian fissure for microsurgical management of MCA aneurysms

BACKGROUND

A wide sylvian opening, with either a proximal or distal start, has been standard for microsurgical management of middle cerebral artery (MCA) aneurysms. However, extensive sylvian dissection is potentially associated with increased incidence of iatrogenic injury to the brain and neurovascular structures. The aim of the present study was to describe the technique of focused opening of the sylvian fissure for microsurgical management of MCA aneurysms with additional tips on handling difficulties which may be encountered with this technique.

METHOD

A 3D image-based anatomic orientation, clipping field-focused surgical planning, slack brain, and high magnification are the basic requirements for this approach. A 10-15 mm sylvian opening is placed so that it allows safe access and a good surgical view of the MCA aneurysm clipping field. Under proximal control of the MCA, the aneurysm neck can be dissected and clipped effectively and safely, in this small surgical field.

RESULTS

The presented technique has been developed and refined by the senior author during the surgery of 1,097 aneurysms over the last 13 years. It has proved to be safe, and effective for clipping of both ruptured and unruptured MCA aneurysms. Its greatest advantages are a shorter operative time and less brain and vessel manipulation compared to more extensive approaches.

CONCLUSION

The focused sylvian opening is a less-invasive alternative to the classical wide sylvian opening for the microsurgical management of most MCA aneurysms.

Endovascular treatment of middle cerebral artery aneurysms for 120 nonselected patients: a prospective cohort study

BACKGROUND AND PURPOSE

Multiple technologies have developed the endovascular approach to MCA aneurysms. We assess the safety and the efficacy of a systematic endovascular approach in nonselected patients with MCA aneurysms and determine predictors of treatment outcomes.

MATERIALS AND METHODS

We analyzed data collected between January 2007 and January 2012 in a prospective clinical registry. All patients with MCA aneurysms treated by means of the endovascular approach were included. A multivariate analysis was conducted to identify predictors of complications, recanalization, and outcome.

RESULTS

A total of 120 patients with 131 MCA aneurysms were included. Seventy-nine patients (65.8%) were treated electively and 41 (34.2%) in the setting of subarachnoid hemorrhage. Thirty-three of 131 aneurysms (25.2%) were treated with simple coiling, 79 aneurysms (60.3%) with balloon-assisted coiling, and 19 aneurysms (14.5%) with stent-assisted coiling. Complications occurred in 13.7% of patients. Stent-assisted coiling was significantly associated with more complications (P = .002; OR: 4.86; 95% CI, 1.60-14.72). At 1 month after treatment, both the permanent morbidity (mRS ≤2) and mortality rates were 3.3%, without any significant difference according to the endovascular techniques. Mean angiographic follow-up was 16.3 months. The rate of recanalization was 15.6% without a statistical difference, according to the technique. Larger aneurysms were a predictor of recanalization (P = .016; OR: 1.183; 95% CI, 1.02-1.36). Retreatment was performed in 10 of 131 aneurysms (7.6%).

CONCLUSIONS

Even though stent-assisted coiling significantly increases the risk of procedural complications, endovascular treatment of MCA aneurysms is safe, effective, and provides durable aneurysm closure in nonselected patients.