Middle Cerebral Artery Bifurcation Research Articles

Assessing Radiation Exposure and Contrast Agent Utilization: A Comparative Analysis of the Woven EndoBridge Device and Stent-Assisted Coil Embolization for Managing Unruptured Wide-Neck Bifurcation Aneurysms.

In this study, we determined whether there were significant differences in procedure time, radiation dose, fluoroscopy time, and total contrast media dose when unruptured wideneck bifurcation aneurysms (WNBAs) were treated with the Woven EndoBridge (WEB) device and stent-assisted coil (SAC) embolization. The WEB device and SAC embolization (14:17) were used to treat 31 cases of internal carotid artery bifurcation, anterior communicating artery, middle cerebral artery bifurcation, and basilar bifurcation aneurysms between August 2021 and December 2022. The procedure time, radiation dose, fluoroscopy time, and total contrast medium dose between the 2 treatment groups were compared and analyzed. In the WEB device group, the results between operators were compared, and the follow-up radiologic outcomes were investigated. The procedure and fluoroscopy times were significantly shorter in the WEB device group. Radiation and total contrast media dose were also significantly smaller in the WEB device, but there was no significant difference in results between operators. The follow-up radiological outcome showed adequate occlusion in 83.3% (10/12) of cases. The WEB device can be used as an alternative treatment method among the available endovascular treatment methods for WNBAs to reduce radiation exposure and the dose of contrast media when used adequately with appropriate indications.

Stent plus balloon-assisted coiling with low-profile braided stents in the treatment of complex wide-necked intracranial bifurcation aneurysms.

Wide-necked bifurcation aneurysms pose significant challenges for endovascular treatment. A recent innovation, the stent plus balloon-assisted coiling technique, combines a stent and a balloon to address these aneurysms effectively. To evaluate the safety and efficacy of the stent plus balloon-assisted coiling for the treatment of wide-necked bifurcation aneurysms. We conducted a retrospective review of our endovascular database to identify patients who were treated with this technique and had a satisfactory angiographic follow-up of at least 24months. Technical success, initial clinical and angiographic outcomes, procedural complications, and follow-up results were analyzed. Angiographic and clinical outcomes were assessed using Modified Raymond-Roy Classification and Modified Rankin Scale, respectively. Our study included 37 aneurysms in 36 patients (26 females) with a mean age of 56.6years. Mean aneurysm and neck sizes were 7.3 ± 3.5mm and 3.7 ± 1.0mm, respectively. Technical success reached 97.2%, with an immediate occlusion rate of 65.7%. At a mean follow-up of 36.5 ± 9.7months, final angiographic follow-up showed a 91.9% complete occlusion rate. Three aneurysms did not achieve complete occlusion; however, none required retreatment. Complications developed in 32.4% of the procedures. Mortality and morbidity rates were 5.4% and 2.7%, respectively. A good clinical outcome was observed in 91.9% of patients. Our results showed that stent plus balloon-assisted coiling technique allows good angiographic outcomes for wide-necked bifurcation aneurysms. However, overall complication rate is high. Subgroup analysis indicated promising safety and efficacy for MCA bifurcation aneurysms, suggesting this technique could be a valuable option for select aneurysms.

Treatment for middle cerebral artery bifurcation aneurysms: in silico comparison of the novel Contour device and conventional flow-diverters.

Endovascular treatment has become the standard therapy for cerebral aneurysms, while the effective treatment for middle cerebral artery (MCA) bifurcation aneurysms remains a challenge. Current flow-diverting techniques with endovascular coils cover the aneurysm orifice as well as adjacent vessel branches, which may lead to branch occlusion. Novel endovascular flow disruptors, such as the Contour device (Cerus Endovascular), are of great potential to eliminate the risk of branch occlusion. However, there is a lack of valid comparison between novel flow disruptors and conventional (intraluminal) flow-diverters. In this study, two in silico MCA bifurcation aneurysm models were treated by specific Contour devices and flow-diverters using fast-deployment algorithms. Computational fluid dynamic simulations were used to examine the performance and efficiency of deployed devices. Hemodynamic parameters, including aneurysm inflow and wall shear stress, were compared among each Contour device, conventional flow-diverter, and untreated condition. Our results show that the placement of devices can effectively reduce the risk of aneurysm rupture, while the deployment of a Contour device causes more flow reduction than using flow-diverters (e.g. Silk Vista Baby). Besides, the Contour device presents the flow diversion capability of targeting the aneurysm neck without occluding the daughter vessel. In summary, the in silico aneurysm models presented in this study can serve as a powerful pre-planning tool for testing new treatment techniques, optimising device deployment, and predicting the performance in patient-specific aneurysm cases. Contour device is proved to be an effective treatment of MCA bifurcation aneurysms with less daughter vessel occlusion.

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

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 (IAs). However, there are no studies that combine these three types of parameters to specifically target MbifA rupture. 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 (DSA) examination to obtain 3D rotational angiography (3D-RA) 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, AR, SR, DNR, HAR, BF, Inflow Angle, Incline Angle, Arterial Angle), 5 geometric parameters (V,S,UI,EI,NSI), and 5 hemodynamic parameters (WSS,MWSS,PAWSS,NWSS,OSI). All the above significant parameters were tested by univariate and multivariate analyses to find out the independent discriminatory factors. 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. 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.

Abstract TMP110: A Novel Model of Ischemia in Rats With Middle Cerebral Artery Occlusion Using a Radiopaque Blood Clot and a Microcatheter Under Fluoroscopy

Introduction: Conventional thromboembolic stroke model requires ligation of the ECA, which is problematic for research of thrombolytic agents because cerebral blood flow is different from human stroke. We aimed to develop a novel thromboembolic stroke model that does not require arterial ligation, using a radiopaque blood clot and microcatheter. Methods: Using male Sprague Dawley rats (n=14) and two sham operated rats were included, a microcatheter (inner diameter, 0.42mm; outer diameter, 0.55mm) was navigated from the caudal ventral artery to the left ICA using fluoroscopy. A blood clot (0.86 mm in diameter, 3 mm in length) containing zirconium dioxide was advanced in the catheter by injection of physiological saline to establish local occlusion. Both fluoroscopy at 1, 3, 6, 24 h and TTC staining at 24 h after stroke model creation were performed. Neurological deficit score was measured. Results: The success rate in selectively embolized of ACA and MCA bifurcation was 93% (13 of 14 cases). The median operating time was 7 min (interquartile range; 4-15 min). The median infarct volume (mm 3 ) was 248 (interquartile range; 239-280) 24 h after occlusion. Neurological deficit scores before and at 1, 3, 6, and 24 h after model creation differed significantly ( P < 0.001). Fluoroscopy showed the position of the radiopaque blood clot remains the same for 24 h after creating the model in 12 of 13 cases (92%). Sham-operated rats revealed no infarction and no neurological deficit. Conclusions: We present a novel rat model for focal infarct only in the MCA territory using a radiopaque blood clot. Fluoroscopy was able to identify whether the blood clot could migrate and recanalize.

Abstract WP142: Investigating the Association of Intracranial Stenosis With Low Wall Shear Stress

Background: Intracranial atherosclerotic disease (ICAD) is associated with high recurrence rates of stroke despite aggressive medical management. Low wall shear stress (WSS) alters endothelial function and changes in WSS within the post-stenotic region of ICAD lesions is a potential driver of stroke recurrence. Methods: Using the SAMMPRIS imaging dataset, we identified medically managed patients with symptomatic middle cerebral artery (MCA) stenosis measured by CTA. WSS was calculated by creating a 3D volumetric mesh from CTA source imaging. Pulsatile flow profile reference standard boundary conditions were applied at pressure outlets to simulate normal hemodynamics. Arterial segments extending from the stenosis to the MCA bifurcation were captured and quantified. Contralateral arterial segments were matched by length and area. The ratio of area with low WSS (<4 dyne/cm 2 ) on both sides was then calculated. Differences in the mean arterial area with low WSS and ratio of area with low WSS were compared using paired Student’s t-test with data presented as mean ± SD. Results: Of 451 cases in SAMMPRIS, the medical management arm had 105 MCA cases of which 47 cases had CTA available and 33 cases were able to be analyzed by computational flow dynamics. Symptomatic ICAD lesions demonstrated significant differences in post stenosis area with low WSS (24.7±43.4 mm 2 vs 2.8±3.4 mm 2 p=0.003) and differences in the low WSS ratio (0.25±0.26 vs0.04±0.05 p<0.001). There was no statistically significant difference in the length and area of the arterial segment post stenosis to the bifurcation and the control length on the contralateral side (11.6±7.4 mm vs 10.6±6.1 mm p=0.566; 80.7±55.0 mm 2 vs 95.4±58.3 mm 2 p=0.298). Conclusion: Area with low WSS after ICAD stenoses is increased in the SAMMPRIS imaging dataset and may be a marker of symptomatic ICAD. Further studies are needed to evaluate the association of post stenotic WSS with symptomatic recurrent stroke.

Clipping of a persistent middle cerebral artery aneurysm after previous flow diverter placement: An illustrative case and review of the literature.

Flow diverter (FD) is increasingly used in the management of wide necked cerebral aneurysms. Despite a reported lower efficacy in middle cerebral artery (MCA) aneurysms, they are still being utilised. Microsurgery is best considered as an index treatment, but can also be a safe and effective treatment when encountering a persistent MCA aneurysm after prior FD. As there is a paucity in literature and more cases of failed FD are expected to appear, we want to add our experience to the existing literature. The microsurgical management of a persistent MCA bifurcation aneurysm, 3 years after a p48 MW HPC Flow Diverter (phenox GmbH, Bochum Germany) insertion is reported and the relevant literature discussed.

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

PurposeIn 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.MethodsOur 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.ResultsThe 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.ConclusionsRegarding 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.

Double Trouble – An Anterior Clinoidal Meningioma with a Concurrent Right MCA Aneurysm

Although meningiomas and cerebral aneurysms are common intracranial pathologies, their coexistence in one patient is rare. We present a case of right anterior clinoid meningioma that has a concurrent right middle cerebral artery (MCA) aneurysm. A 55-year-old female complaining of right-sided visual loss was admitted to our department after magnetic resonance imaging (MRI) revealed a right anterior clinoid meningioma that was extending to sella turcica and expanded superiorly, compressing the optic chiasm. With a plan of transnasal transsphenoidal endoscopic excision, a preoperative computed tomography angiogram was obtained, per our protocol. This revealed an incidental 3 mm right MCA bifurcation aneurysm. Due to the possibility of postoperative aneurysm bleeding, the patient was operated on with a right-sided pterional craniotomy. After 5 days of postoperative follow-up, the patient was discharged without complications. The histopathological analysis confirmed the diagnosis of psammomatous meningioma. This case underlines the importance of preoperative planning and being vigilant for incidental findings that might cause fatal consequences.

Middle cerebral artery bifurcation aneurysms are associated with patient age, sex, bifurcation angle, and vascular diameters

To investigate the relationship of the middle cerebral artery (MCA) bifurcation aneurysms with patients’ age and sex, vascular angles at the bifurcation, and diameters of the M1 and two M2 arteries, patients with and without MCA aneurysms were retrospectively enrolled. The lateral angles, MCA bifurcation angle and arterial diameter were measured and analyzed. Totally, 121 (19.0%) patients with and 517 (81.0%) without MCA aneurysms were enrolled. Most (n = 88 or 72.7%) aneurysms were present in the age range of 40–70 years, and significantly (P = 0.01) more women than men had the bifurcation aneurysms. The MCA bifurcation angle was significantly greater (149.2° ± 32.6° vs. 107.2° ± 26.3°; P < 0.0001) while both the smaller and larger lateral (M1/M2) angles were significantly smaller in patients with than without aneurysms (82.0° ± 23.7° vs. 109.1° ± 22.7° with P < 0.001 for the smaller and 123.2° ± 25.2° vs. 139.5° ± 16.9° with P < 0.001 for the larger lateral angle). 109 (90.1%) bifurcation aneurysms deviated towards the smaller lateral angle, and 103 (85.1%) aneurysms deviated towards the thinner M2 branch. The maximal aneurysm diameter ranged 1.6–13.8 (mean 5.4 ± 2.4) mm and was significantly (P < 0.05) positively correlated with the diameter of both M2 arterial branches (R = 0.57 and P = 0.01 for the smaller M2, and R = 0.69 and P = 0.002 for the larger M2) or the MCA bifurcation angle. A significant (P < 0.0001) negative correlation was detected between age and the smaller lateral angle but a significant (P < 0.0001) positive correlation between age and the MCA bifurcation angle in patients without MCA bifurcation aneurysms or in the total patients. MCA bifurcation angle was the only significant (P = 0.0001, odds ratio 2.7, 95% confidence interval 1.6–3.8) independent risk factor for MCA bifurcation aneurysm presence, with the bifurcation angle threshold of 124.1° and an area under the ROC curve of 0.86. In conclusion, significantly more MCA bifurcation aneurysms are present in older patients, females, and patients with a wider MCA bifurcation angle, and deviate towards the smaller lateral angle and the thinner M2 segment. MCA bifurcation angle is the only independent risk factor for presence of MCA bifurcation aneurysms with the threshold of 124.1°.

Numerical investigation of unruptured middle cerebral artery bifurcation aneurysms: influence of aspect ratio

An aneurysm is a disease condition, which is due to the pathological weakening of an arterial wall. These aneurysms are often found in various branch points and bifurcations of an artery in the cerebral circulation. Most aneurysms come to medical attention, either due to brain hemorrhages caused by rupture or found unruptured. To consider surgically invasive treatment modalities, clinicians need scientific methods such as, hemodynamic analysis to assess rupture risk. The arterial wall loses its structural integrity when wall shear stress (WSS) and other hemodynamic parameters exceed a certain threshold. In the present study, numerical simulations are carried out for unruptured middle cerebral artery (MCA) aneurysms. Three distinct representative sizes are chosen from a larger patient pool of 26 MCA aneurysms. Logically, these aneurysms represent three growth stages of any patient with similar anatomical structure. Simulations are performed to compare the three growth phases (with different aspect ratios) of an aneurysm and correlate their hemodynamic parameters. Simulations with patient specific boundary conditions reveal that, aneurysms with a higher aspect ratio (AR) correspond to an attendant decrease in both time-averaged wall shear stress (TAWSS) and spatial wall shear stress gradients (WSSG). Smaller MCAs were observed to have higher positive wall shear stress divergence (WSSD), exemplifying the tensile nature of arterial wall stretching. Present study identifies positive wall shear stress divergence (PWSSD) to be a potential biomarker for evaluating the growth of an aneurysm.

Abstract 111: Woven Endo Bridge‐Coil Embolization of a Middle Cerebral Artery Bifurcation Aneurysm with Secondary Lobule

Introduction 18‐36% of all intracranial aneurysms are middle cerebral artery(MCA) bifurcation aneurysms. While some are much higher risk than others, they have an overall low estimated annual rupture rate of 0.36%.(1) MCA bifurcation aneurysms have been historically challenging to treat endovascularly given they often have complex morphology and wide necks. The Woven EndoBridge (WEB) is an ellipsoid embolization device designed to provide intrasaccular flow disruption along the aneurysm neck, which has been proven to be an effective method in treating a wide spectrum of wide‐necked bifurcation aneurysms. Thromboembolism and recanalization are the main concerns in treatment with the WEB device, like any aneurysm treatment approach .(2),(3) Occasionally, irregularities and secondary lobules at the base of the primary aneurysm can have persistent filling despite treatment. Methods We present a case of a right MCA bifurcation aneurysm treated by a WEB device and coil embolization. Results 48‐year‐old female with a medical history significant only for active smoking who presented with sudden onset of the worst headache of her life followed by brief loss of consciousness. No neurological evaluation was sought initially, until 2 weeks later as she continued to experience a moderate‐intensity headache associated with nausea and vomiting with frequent falls. On exam, she was alert and oriented, moving all extremities with full strength. CT head revealed an evolving acute to subacute right MCA infarction with adjacent small volume subarachnoid hemorrhage. CTA head revealed a right MCA bifurcation aneurysm measuring 6 x 6 x 7 mm with irregularity of the wall. Multifocal severe stenosis was noted in the right distal right M1 and right M2 divisions. She underwent a diagnostic subtraction angiography which confirmed an irregular right MCA bifurcation aneurysm measuring 4.3 x 4.5 x 5.7 mm (Figure 1 ‐A,B). While it was believed that the subarachnoid hemorrhage was more likely related to the recent infarct, a decision was made to treat the aneurysm given its relatively large size and irregular shape. Embolization was performed with a WEB SL 6 x 4 mm device (Figure 1: C,D ‐blue arrow). Post‐deployment angiograph showed occlusion of the aneurysm dome but persistent filling of the secondary lobule near the base of the aneurysm. Given this residual lobule filling, a decision was made to continue additional embolization with a hyper soft 3D 2 mm X 2 cm coil(Figure 1: C,D ‐ yellow arrow). Final angiography revealed complete occlusion of the aneurysm. Vasospasm of the distal M2 divisions and multiple M3 branches in the right MCA vascular territory was also noted. Therefore, she was treated with 20 mg of intra‐arterial Verapamil with improvement. She was started on Aspirin 325 mg daily. Daily transcranial dopplers were negative for vasospasm. She remained neurologically stable and was discharged home 5 days after admission ambulating independently. Conclusion With modern advances in endovascular devices, many MCA bifurcation aneurysms can be treated minimally invasively. However, there are some limitations to the WEB since every aneurysm is different and there are a finite number of sizes and shapes available for WEB. This case illustrates that adjunctive coil embolization can successfully occlude a residual secondary base lobule after WEB embolization.

Abstract 037: Aneurysm Occlusion Rates with WEB Treatment: Single‐Institution Study and Review

Introduction To provide our single‐institution experience and outcome data with the WEB device in 51 patients treated for ruptured and unruptured intracranial aneurysms. Methods Occlusion rates in a cohort of 51 patients treated with WEB were collected at time of procedure and at last follow‐up between the years 2019 and 2021. Angiographic outcomes were assessed on the WEB occlusion scale (WOS) and occlusion status scale (OSC). Compaction was assessed on imaging. Functional outcomes were assessed using the modified Rankin Scale. Thromboembolic complications and retreatments were recorded. Statistical analysis was performed to identify predictors of inadequate occlusion. Results A total of 51 patients underwent endovascular embolization using the WEB device with a mean follow‐up of 14.9 months. Ruptured aneurysmal subarachnoid hemorrhage accounted for 15.7% (8/51) of all patients. Most of the patients (92.1%) were functionally independent at presentation. The most common aneurysm location in the present study was MCA bifurcation (52.9%). The median maximal aneurysm diameter was 6.9mm, while the median neck size was 4.4mm. Last follow‐up consisted of 49 patients and imaging was obtained in 45 patients. Adequate occlusion was documented at 97.8% (WOS) and 93.3% (OSC). Retreatment was required in 1 aneurysm. Minor compaction was noted in 11.1% with no cases of major compaction. The majority of patients had the same presenting and post‐procedure mRS. Thromboembolic complications were encountered in 7.8% (4/51) of procedures; 3 of which were symptomatic and none were permanent. There were no hemorrhagic complications. An analysis of the data shows that larger aneurysm dimensions, necessity for adjunctive stent, and minor compaction were significantly associated with inadequate occlusion. Aneurysm height and dome width remained independent predictors of inadequate occlusion Conclusion This study confirms the safety and efficacy profile of the WEB device for the embolization of intracranial aneurysms at our institution. A high rate of adequate occlusion at a midterm follow‐up demonstrates high efficacy of the WEB device in our experience. Predictors of inadequate occlusion, which we explored, proved consistent with the literature on known variables associated with residual aneurysms.

CLinical EValuation of WEB 17 device in intracranial aneuRysms (CLEVER): procedural, 30-day and 1-year safety results for ruptured and unruptured aneurysms

BackgroundIntrasaccular flow disruption is an endovascular approach for the treatment of wide-neck aneurysms and, more specifically, wide-neck bifurcation aneurysms, which are challenging to treat with previously developed technologies. The Woven...

Individualized Periprocedural and Intraprocedural Management for Coil Embolization of Unruptured Cerebral Aneurysm in a Patient with Severe Thrombocytopenia due to Liver Cirrhosis

A female patient in her early 60's with advanced liver cirrhosis and thrombocytopenia having a platelet count under 30,000/µL, visited an outpatient clinic. Computed tomography angiography revealed an unruptured aneurysm on the left middle cerebral artery bifurcation with 6.0 mm of maximal diameter. Endovascular coiling was planned, considering the patient's medical condition. Eight pints of platelet concentrate were transfused 6 hours before the procedure, and a platelet count of 57,000/ µL was achieved 3 hours before the procedure. No antiplatelet premedication and intraprocedural heparin was administered. A bail-out use of intra- or postoperative Tirofiban (Aggrastat®) was prepared for inadvertent thromboembolic events. The aneurysm was successfully occluded with no procedure-related event. The patient’s hospital course was uneventful, and she was discharged without complications. Despite the potential hemorrhagic risk caused by hemostatic failure in patients with cirrhosis, successful endovascular coiling can be performed with highly individualized management.

Arterial Bypass in the Treatment of Complex Middle Cerebral Artery Aneurysms: Lessons Learned from Forty Patients

Complex MCA aneurysms incorporating parent or branching vessels are often not amenable to standard microsurgical clipping or endovascular embolization treatments. We aim to discuss the treatment of such aneurysms via a combination of surgical revascularization and aneurysm exclusion based on our institutional experience. Thirty-four patients with complex MCA aneurysms were treated with bypass and aneurysm occlusion, five with surgical clipping or wrapping only, and one with aneurysm excision and primary re-anastomosis. Bypasses included STA-MCA, double-barrel STA-MCA, OA-MCA, and ECA-MCA. Following bypass, aneurysms were treated by surgical clipping, Hunterian ligation, trapping, or coil embolization. The average age at diagnosis was 46 years. 67% of the aneurysms were large and most involved the MCA bifurcation. Most bypasses performed were STA-MCA bypasses, 12 of which were double-barrel. There were two wound healing complications. All but two of the aneurysms treated demonstrated complete occlusion at the last follow up. There were three hemorrhagic complications, three graft thromboses, and four ischemic insults. Mean follow up is 73 months. 83% of patients reported stable or improved symptoms from presentation and 73% reported a functional status (GOS 4 or 5) at the latest available follow up. Cerebral revascularization by bypass followed by aneurysm or parent artery occlusion is an effective treatment option for complex MCA aneurysms that cannot be safely treated by standard microsurgical or endovascular techniques. Double-barrel bypass consisting of two STA branches to two MCA branches yields adequate flow replacement in the majority of cases.

Variations of Middle Cerebral Artery Hemodynamics Due to Aneurysm Clipping Surgery

Abstract Cerebral aneurysms are potentially life-threatening cerebrovascular conditions where a weakened blood vessel in the brain bulges or protrudes over time. The most common way to treat aneurysms is surgical clipping, an approach where blood flow to the aneurysm is blocked by a permanently placed clip on the artery. However, not all aneurysms are identical; thus, there has been a need for patient-specific treatment options, where each aneurysm is treated based on its individual characteristics. Computational fluid dynamics (CFD) modeling can offer insights to predict how different treatment procedures will affect cerebral hemodynamics. In that regard, the goal of this pilot study was to investigate the flow characteristics and hemodynamic parameters in cerebral arteries before and after neurosurgical clipping. For this purpose, two patient-specific cerebral artery geometries with at least one aneurysm at the middle cerebral artery bifurcation were selected from an online dataset. A companion postclipping model was created for each geometry by removing the aneurysm from the original geometry. Tetrahedral mesh elements were then generated and CFD simulations were conducted to compare the blood velocity profile, secondary flow, flow streamline, and wall shear stress in the computational models with and without aneurysm. Results showed that the clipping treatment led to changes in the velocity profiles, secondary flow structures, and wall shear stress in the middle cerebral artery. In conclusion, our results suggest that CFD modeling can assist in predicting hemodynamic parameters prior to treatment, thus facilitating more tailored planning for each patient’s treatment.

Embolization of unruptured wide-necked aneurysms at the MCA bifurcation using the Neuroform atlas stent-assisted coiling: a two-center retrospective study.

The management of middle cerebral artery (MCA) aneurysms remains a controversial topic, and MCA aneurysms have traditionally been treated primarily by surgical clipping. The Neuroform Atlas Stent™ (NAS, available from Stryker Neurovascular, Fremont, California) represents the latest generation of intracranial stents with improved stent delivery system capabilities. This study aims to investigate the safety, feasibility and efficacy exhibited by NAS in treating unruptured aneurysms at the MCA bifurcation. This was a two-center retrospective study involving 42 patients with unruptured wide-necked aneurysms (WNAs) of the MCA treated with the NAS from October 2020 to July 2022. The stent was used to treat 42 cases of unruptured WNA at the MCA bifurcation. Endovascular treatment techniques had a 100% success rate. Immediate postoperative angiography found complete aneurysm occlusion in 34 patients (80.9%) (mRRC 1), neck remnant in 7 patients (16.7%) (mRRC 2), and residual aneurysm in 1 patient (2.4%) (mRRC 3). The thromboembolic complication rate was 2.4% (1/42). The follow-up period was 8.7 months on average (3-16 months). The last angiographic follow-up results revealed complete aneurysm occlusion in 39 patients (92.9%) (mRRC 1), neck remnant in 3 (7.1%) patients (mRRC 2), no aneurysm recanalization or recurrence, and no cases of stent intimal hyperplasia. During the latest clinical follow-up, all patients had an mRS score of 0. Our study demonstrates that the NAS can be applied to treat unruptured WNAs at the MCA bifurcation with favorable safety, feasibility, and efficacy.

Flow diversion for the treatment of intracranial bifurcation aneurysms: a systematic review and meta-analysis

BackgroundFlow diversion (FD: flow diversion, flow diverter) is an endovascular treatment for many intracranial aneurysm types; however, limited reports have explored the use of FDs in bifurcation aneurysm management. We...

WEB (Woven EndoBridge) device for intracranial aneurysm treatment: technical, radiological, and clinical findings in a consecutive North American cohort.

Utilization of Woven EndoBridge (WEB) for treatment of intracranial aneurysms has increased due to increasing operator experience. We aimed to report our contemporary series of a North American center with the WEB, examining factors associated with occlusion rates. Consecutive patients (2019-2022) with intracranial aneurysms treated with WEB device were included. Through a univariate and multivariate analysis, independent predictors of adequate occlusion (RR1/RR2) were examined. Procedural and clinical results were reported. A total of 104 consecutive aneurysms/patients (25 men/79 women; median age, 63years, IQR: 55-71) were treated with single-layer WEB-SL in our institution. Seventeen patients (16%) had a ruptured aneurysm. The median aneurysm dome size was 5.5mm (IQR = 4.5-6.5), and the most common locations were AcomA (36/104 = 34.6%), MCA bifurcation (29/104 = 27.9%), and BT (22/104 = 21.2%). The rate of technical failure was 0.9%. The median intervention time was 32min (IQR = 25-43). Overall, 8 (7.6%) cases needed additional interventions: 4 (3.8%) additional stenting, 3 cases (3.8%) of intravenous tirofiban infusion (because of the excessive WEB protrusion), and one case (0.9%) of additional coiling (need to complete the neck occlusion). At 12-month follow-up, 67 patients were available showing 59/67 (88%) and 6/67 (9%) of complete occlusion and neck remnant, respectively on dual-energy CTA. There were no cases necessitating retreatment. Ruptured presentation (OR = 0.09, 95% CI = 0.008-0.9, p = .024), undersized WEB (OR = 15, 95% CI = 1.2-50, p = .006), WEB shape change (OR = 0.07, 95% CI = 0.001-0.6, p = .05), aneurysm neck diameter (OR = 0.4, 95% CI = 0.2-0.9, p = .05), and angle between the parent artery and the aneurysm dome (OR = 0.2, 95% CI = 0.01-0.8, p = .008) were significantly associated with occlusion status (RR1-2) at follow-up. However, in the multivariate logistic regression, these factors did not reach the statistical significance. The overall rate of morbidity was 0.9%. Our contemporary North American experience on consecutive intracranial aneurysms treated with WEB confirms the medium-term efficacy of this strategy, with low procedural time and morbidity. Further research is needed to demonstrate long-term occlusion rates.