Aneurysm Neck Research Articles

Handmade models for aneurysm surgery: A useful tool for training.

Aneurysm surgery is considered difficult by young and trainee neurosurgeons. This is due to difficulty in understanding orientation of aneurysm complex (proximal and distal vessels, aneurysm neck, and fundus) in relation to the surrounding structures (skull, brain, vessels, and nerves) after head is rotated, extended, and fixed on the head frame. Virtual three-dimensional (3D) imaging studies and 3D-printed models help young neurosurgeons but are not accessible to most of the centers due to need for resources (human and equipment). Authors used handmade 3D models of aneurysm complex to train young neurosurgeons before and during surgery to make them understand steps to treat it. RadiAnt DICOM viewer software (2022.1.1, 64-bit, Medixant, Poznan, Poland) was used for acquiring 3D Volume Rendering Technique images to make aneurysm models preoperatively. Twisted 20 Gauze galvanized iron wires were used for making proximal and distal branches and Epoxy Putty (M-seal, Pidilite ® industries, Mumbai, India) was used to make smooth surfaces of the vessels, aneurysm necks, and fundi. Models were used in operating room (OR) before and during surgery to help surgeons and trainees get oriented to the aneurysm complexes. Handmade models, oriented as per patients' head position, were useful to make surgeons and trainees to understand projection of various components of the aneurysm complex in relation to adjacent structures, especially skull base, during both preoperative planning and in OR even before completion of the dissection. Handmade models of aneurysms are inexpensive tool and can help trainee neurosurgeons to plan and execute surgical management of aneurysms.

Investigation of the Use of Hollow Elastic Biomodels Produced by Additive Manufacturing for Clip Choice and Surgical Simulation in Microsurgery for Intracranial Aneurysms

Intracranial aneurysms (IAs) are dilatations of the cerebral arteries, whose treatment is commonly based on the implant of a metallic clip on the aneurysm neck. Despite the dissection and understanding of the surgical anatomy of the IA when often only parts of it are visible, the choice of the ideal clip to be used is one of the surgical difficulties. Although current imaging tests guarantee IA visualization, currently there is no planning method that allows for a real three-dimensional (3D) visualization for optimal choice of clip prior to surgery. The aim of this study is to evaluate whether IA biomodels generated by additive manufacturing methods are useful for surgical clip selection in microsurgeries for IA. Three-dimensional (3D) IA biomodels of 10 patients with IA were evaluated using computerized tomography, surgical microscope, and 3D printer. The research was divided into 4 phases as follows: development of the 3D biomodels, evaluation of the biomodel dimensional characteristics, surgical planning evaluation with the biomodel and its clipping effectiveness, and evaluation of the actual surgical simulation process within the models. Ten 3D biomodels were obtained, made of a malleable and hollow part, formed by the IA and related arteries, and another rigid part, mimicking the skull and other arteries of the skull base. Based on these 3D models, 10 clips were chosen during the surgical planning, and all exactly matched the clip characteristics used during the actual surgeries. The surgical simulation with the biomodels performed by 2 neurosurgeons still in training obtained 100% accuracy in the identification of the clips that were eventually used during the actual surgeries. 3D biomodels generated by additive manufacturing methods were effective for surgical clip selection in microsurgeries for IA, reducing surgical time, increasing cerebral angioarchitecture understanding, and providing more safety in this type of surgery.

Ultrashort Echo Time Magnetic Resonance Angiography as an Alternative Tool to Digital Subtraction Angiography in the Follow-up of Stent-Assisted Coil Embolization Outcomes.

Follow-up of aneurysms treated with stent-assisted coil embolization has been performed using digital subtraction angiography (DSA) because in time-of-flight magnetic resonance angiography, metal artifacts from the stent often affect visualization. To confirm whether ultrashort echo time (TE) MRA may be an alternative for DSA during follow-up. Patients with unruptured aneurysms initially treated with stent-assisted coil embolization between April 2019 and March 2021 were enrolled. After 3 months of treatment, follow-up DSA and ultrashort TE MRA were performed. All images were independently reviewed by neurosurgeons to evaluate in-stent flow and rated from 1 (not visible) to 4 (excellent). Aneurysmal embolization status was assessed as complete obliteration, residual neck, or residual aneurysm. Ultrashort TE MRA findings were classified as evaluative or nonevaluative state based on the presence of metal artifacts. We investigated the types of aneurysms that were evaluative and the agreement between ultrashort TE and DSA. Overall, 89 aneurysms were examined, of which 74% (n = 66) were classified as evaluative on ultrashort TE. Significant differences were observed in size and stent type. Evaluative cases had an aneurysm size of <7 mm ( P = .0007) and a higher rate of Neuroform Atlas ( P = .0006). The rate of agreement between ultrashort TE with evaluative state and DSA was 95%. Ultrashort TE MRA could evaluate an embolization status treated with stenting, and the findings are in excellent agreement with those of DSA. Aneurysms measuring <7 mm and treated with Neuroform Atlas are evaluative on ultrashort TE, and DSA might not be necessary.

Alternate Simultaneous Bilateral Carotid Angiography in Y-stent−Assisted Coil Embolization for an Anterior Communicating Artery Aneurysm with Triplicate A2 Variant

The triplicate A2 variant is one of several common anomalies of the anterior cerebral artery. An anterior communicating artery aneurysm with triplicate A2 variant in close proximity to the aneurysm neck is challenging to treat due to potential unilateral/bilateral corpus callosum or parietal lobe infarction. Alternate simultaneous bilateral carotid angiography can differentiate triplicate A2 branches through time-difference alternate injection of contrast into the carotid arteries bilaterally, which can enhance anatomic understanding of complex anterior communicating artery aneurysms during complex endovascular treatment. In this case, a complex aneurysm with an associated triplicate A2 variant was treated successfully with Y-stent-assisted coil embolization using alternate simultaneous bilateral carotid angiography.

Endovascular versus neurosurgical aneurysm treatment: study protocol for the development and validation of a clinical prediction tool for individualised decision making

IntroductionTreatment decisions for aneurysmal subarachnoid haemorrhage patients should be supported by individualised predictions of the effects of aneurysm treatment. We present a study protocol and analysis plan for the development...

Rupture risk parameters upon biomechanical analysis independently change from vessel geometry during abdominal aortic aneurysm growth

ObjectiveThe indication for abdominal aortic aneurysm (AAA) repair is based on a diameter threshold. However, mechanical properties, such as peak wall stress (PWS) and peak wall rupture index (PWRI), influence the individual rupture risk. This study aims to correlate biomechanical and geometrical AAA characteristics during aneurysm growth applying a new linear transformation-based comparison of sequential imaging. MethodsPatients with AAA with two sequential computed tomography angiographies (CTA) were identified from a single-center aortic database. Patient characteristics included age, gender, and comorbidities. Semiautomated segmentation of CTAs was performed using Endosize (Therenva) for geometric variables (diameter, neck configuration, α/β angle, and vessel tortuosity) and for finite element method A4 Clinics Research Edition (Vascops) for additional variables (intraluminal thrombus [ILT]), vessel volume, PWS, PWRI). Maximum point coordinates from at least one CTA 6 to 24 months before their final were predicted for the final preoperative CTA using linear transformation along fix and validation points to estimate spatial motion. Pearson’s correlation and the t test were used for comparison. ResultsThirty-two eligible patients (median age, 70 years) were included. The annual AAA growth rate was 3.7 mm (interquartile range [IQR], 2.25-5.44; P < .001) between CTs. AAA (+17%; P < .001) and ILT (+43%; P < .001) volume, maximum ILT thickness (+35%; P < .001), β angle (+1.96°; P = .017) and iliac tortuosity (+0.009; P = .012) increased significantly. PWS (+12%; P = .0029) and PWRI (+16%; P < .001) differed significantly between both CTAs. Both mechanical parameters correlated most significantly with the AAA volume increase (r = 0.68 [P < .001] and r = 0.6 [P < .001]). Changes in PWS correlated best with the aneurysm neck configuration. The spatial motion of maximum ILT thickness was 14.4 mm (IQR, 7.3-37.2), for PWS 8.4 mm (IQR, 3.8-17.3), and 11.5 mm (IQR, 5.9-31.9) for PWRI. Here, no significant correlation with any of the aforementioned parameters, patient age, or time interval between CTs were observed. ConclusionsPWS correlates highly significant with vessel volume and aneurysm neck configuration. Spatial motion of maximum ILT thickness, PWS, and PWRI is detectable and predictable and might expose different aneurysm wall segments to maximum stress throughout aneurysm growth. Linear transformation could thus add to patient-specific rupture risk analysis. Clinical RelevanceAbdominal aortic aneurysm rupture risk assessment is a key feature in future individualized therapy approaches for patients, since more and more data are obtained concluding a heterogeneous disease entity that might not be addressed ideally looking only at diameter enlargement. The approach presented in this pilot study demonstrates the feasibility and importance of measuring peak wall stress and rupture risk indices based on predicted and actual position of maximum stress points including intraluminal thrombus.

Long term WEB results - still going strong at 5 years?

The aim of our multi-center study is to examine 5-year radiological outcomes of intracranial aneurysms (IAs) treated with the Woven EndoBridge (WEB). All patients treated with WEB between January 2013 and December 2016 were included. Patient and aneurysm characteristic data was collected from the electronic patient record. Aneurysm occlusion was assessed using a 3-grade scale: complete occlusion, neck remnant, and aneurysm remnant. Complete occlusion and neck remnant were considered as adequate occlusion, whereas aneurysm remnant was assessed as an inadequate occlusion. A total of 66 patients (72.7% female) with 66 IAs (n = 25 acutely ruptured) were treated with WEB. The mean age of patients was 55.6 years (range: 36-71 years). The mean width of the aneurysm neck was 4.5 mm (range: 2-9 mm). 5-year imaging follow-up data was not available for 16.6% patients (n = 11). During the follow up period, 14.5% of IAs (n = 8/55) required retreatment within 24 months of initial treatment with the WEB. A total of 55 IAs were analyzed for 5-year radiological outcome. Of these, including IAs required retreatment, 47.3% of IAs (n = 26/55) were occluded completely, 36.4% (n = 20/55) had neck remnant and 16.3% (n = 9/55) had recanalized. 83.7% of IAs were occluded adequately. None of the IAs rebled after initial treatment with WEB. WEB can provide acceptable adequate occlusion rates at 5 years. Furthermore, recanalization appears to be unlikely after the first two years post-treatment. The results of large studies are needed to confirm these promising long term radiological outcomes.

The safety and effectiveness of the Contour Neurovascular System for the treatment of wide-necked aneurysms: A systematic review and meta-analysis of early experience.

The Contour is a new generation intrasaccular flow disruption tool that aims to cover the aneurysm neck and is sized according to the neck diameter. While several case series have been published, no literature review has been performed on this promising device. To assess the safety and effectiveness profile of the Contour Neurovascular System for wide-necked aneurysms. We followed the recommendations of the PRISMA checklist Four databases were searched with a supplemental manual search. All data were analyzed using R software version 4.2.1. We finally included six studies with 131 treated aneurysms. The overall procedural time was 97.27 (95% CI = 70.07-124.47) minutes, ranging from 78.9 to 136.0 min. The pooled adequate occlusion rate was 84.21% (95% CI = 75.45-90.25), and the overall functional independence rate was 94.74% (87.97-97.79). The overall adverse event rate was 4.70 (95% CI = 3.24-6.76), varying among different events from 0.78 to 8.53%. Thromboembolic events were the most commonly encountered in 8.53% of the patients (95% CI = 4.78-14.74), followed by headache and minor stroke with incidence rates of 5.88 (95% CI = 2.83-11.83) and 4.35 (95% CI = 1.41-12.63), respectively. The overall procedural time in studies using the Contour system only was 86.17 (95% CI = 68.70-10.64) minutes, while it was 136 (95% CI = 90.96-181.04) in the Contour-assisted coiling procedures. However, both techniques were comparable regarding adequate occlusion rates and functional independence. With the anticipation of future studies, the Contour Neurovascular System is a safe and effective treatment option for wide-necked intracranial aneurysms.

LVIS EVO stent-through-balloon after hydrocoil embolization of intracranial aneurysms: One-year results.

To evaluate the durability and safety of complete intracranial aneurysm occlusion at one year using the low-profile braided intracranial LVIS EVO stent. This is a retrospective, monocentric, observational study of unruptured wide-necked intracranial aneurysms treated with the LVIS EVO stent-through-balloon technique after balloon-assisted hydrocoil embolization. Imaging and clinical data were assessed by two blinded independent neuroradiologists and neurologists, respectively. Primary endpoint was complete angiographic occlusion on day 0 and at 12 months. Secondary endpoints included clinical safety using the modified Rankin scale (mRS), ischemic and hemorrhagic adverse events, parent vessel stenosis > 50% or occlusion and retreatment rate. 103 aneurysms in 103 patients were included (53 years-old, 77% women). Mean aneurysm size and neck were 7 and 4 mm, respectively. Complete occlusion was 97% initially and 90% at 12 months, with pending follow up in 17.5% patients. Five patients (5%) with partially stented necks were retreated with a second stent in a T-configuration. Two stents failed to open initially and were immediately retrieved. Asymptomatic parent vessel occlusion and severe in-stent stenosis occurred in 1% and 3%, respectively. The 12-month procedure-related permanent neurological deficit and mortality rates (mRS 3-6) were 2% and 1%, respectively. There was one fatal bleeding but no large ischemic complications. Delivering the LVIS EVO stent through a dual lumen balloon after balloon-assisted hydrocoil embolization yields a high and stable rate of complete aneurysm occlusion at one year with a reasonable immediate and delayed complication rate.

Transradial Stent-Assisted Coiling Using “Dual-Jailing” Technique for Kissing Aneurysms of the Internal Carotid Artery: Technical Note and Literature Review

Kissing aneurysms are an unusual type of multiple intracranial aneurysms having different origins with partially adherent walls. Although endovascular treatment is a useful alternative to surgical clipping, endovascular management for small wide-necked kissing aneurysms has not been adequately investigated to date. Herein, we present a case of small wide-necked kissing aneurysms successfully treated with transradial stent-assisted coiling (SAC) using the "dual-jailing" technique. We also performed a review of the relevant literature. A 64-year-old woman who was diagnosed with small wide-necked kissing aneurysms relating to the ophthalmic artery underwent SAC using the dual-jailing technique. After a 6F Simmons guiding sheath was delivered into the target common carotid artery via transradial access, a 6F intermediate catheter was navigated into the petrous internal carotid artery to achieve both triple microcatheter manipulation and contrast injection. Two coil-delivery microcatheters were cannulated into each aneurysm, followed by a Neuroform Atlas stent deployment over the aneurysm necks via a third stent-delivery microcatheter. By using the jailed microcatheters, SAC of the kissing aneurysms was successfully achieved, preserving the ophthalmic artery. The postprocedural course was uneventful. A follow-up magnetic resonance angiography showed no evidence of recanalization 2years 3months post procedure. The dual-jailing technique may provide simple and time-saving SAC compared with previous reported method. This technique can be a useful treatment option for small wide-necked kissing aneurysms.

Identifying high risk for proximal endograft failure after endovascular aneurysm repair in patients suitable for both openand endovascular elective aneurysm repair.

Proximal endograft failure (type Ia endoleak or migration) after endovascular aneurysm repair (EVAR) is associated with hostile aneurysm neck morphology. Neck scoring systems were developed to predict proximal endograft failure but were studied in retrospective studies, which, due to selection bias, may have led to an overestimation of bad outcomes after EVAR. To predict patients who benefit from open repair, preoperative neck morphology and occurrence of long-term proximal endograft failure were investigated in patients enrolled in the endovascular arm of the Dutch Randomized Endovascular Aneurysm Management (DREAM) trial who were suitable for open repair by definition and have long-term follow-up. A post-hoc on-treatment analysis of patients after EVAR was performed in 171 patients. Aneurysm neck morphology was quantified using the aneurysm severity grading (ASG) neck score calculated on preoperative computed tomography angiography images. The ASG neck score was used to predict proximal endograft failure. Receiver operating characteristic analysis was performed to calculate a threshold to divide favorable and unfavorable aneurysm necks (low and high risk); positive and negative likelihood-ratios were calculated accordingly. Freedom from proximal endograft failure was compared between groups using Kaplan-Meier analysis. During a median follow-up of 7.6years, 20 patients suffered proximal endograft failure. Receiver operating characteristic analysis showed an area under the curve of 0.77 (95% confidence interval [CI], 0.65-0.90; P< .001), indicating acceptable prediction. The threshold was determined at ASG neck score ≥5; 30 patients had unfavorable neck morphology, of whom 11 developed proximal endograft failure. The positive likelihood-ratio was 4.4 (95% CI, 2.5-7.8), and the negative likelihood-ratio was 0.51 (95% CI, 0.3-0.8). Twelve years postoperatively, freedom from proximal endograft failure was 91.7% in the favorable group and 53.2% in the unfavorable group, a difference of 38.5% (95% CI, 13.9-63.1; P<.001). In this study, the ASG neck score predicted proximal endograft failure during the entire follow-up. This exhibits the persistent risk for proximal endograft failure long after EVAR and calls for ongoing surveillance especially in patients with unfavorable aneurysm necks.

Opposite L-configuration double stenting for rupture of an extremely wide-necked anterior communicating artery aneurysm at the acute stage: illustrative case.

Wide-necked aneurysms can be treated by double stenting in an X- or Y-configuration or by a double waffle-cone technique. However, some aneurysms remain untreatable. The rupture of a complex wide-necked anterior communicating artery (AcomA) aneurysm that caused acute subarachnoid hemorrhage (SAH) was treated successfully using double stents with an opposite L-configuration as an alternative to the X-stent technique. The aneurysm involved both A1-A2 junctions in the aneurysm neck with acutely oriented A2 segments of the anterior cerebral artery bilaterally. It was densely packed and completely obliterated angiographically with preserved blood flow by implanting each stent in the ipsilateral A1-A2 bilaterally. Blood flow from the left A1 to the right A2 was confirmed through the AcomA on injection of the left internal carotid artery immediately after the procedure without critical infarction in the subthalamic area. Although the AcomA was not demonstrated by injection of the left internal carotid artery on angiography at 3 months or 1 year later, no cerebral infarction was seen on magnetic resonance images at the final hospital visit. Opposite L-configuration double stenting was used successfully as rescue stent-assisted coiling for a rupture of a complex wide-necked AcomA aneurysm in a patient with acute SAH.

Comparative clinical study of short-term outcomes between table fenestrated and chimney endovascular aneurysm repair for hostile neck aneurysms.

Hostile neck abdominal aortic aneurysm (AAA) is challenging for standard endovascular aneurysm repair (EVAR). We sought to compare fenestrated endovascular aneurysm repair (fEVAR) and chimney endovascular aneurysm repair (chEVAR) for hostile neck AAA. Patients were identified retrospectively. Hostile neck anatomy was defined as a proximal neck length of <15mm or angulation >60°. The choice of fEVAR or chEVAR was based on neck anatomy and physician preference. Type I endoleak (T1EL) was the primary outcome. Other outcomes included type III endoleak (T3EL), visceral stent occlusion, renal insufficiency, reintervention, and mortality. A total of 84 patients were included from April 2012 to December 2021. fEVAR and chEVAR patients were 48 and 36 cases, respectively. Both groups showed similar rate of T1EL, T3EL, visceral stent occlusion, renal insufficiency, reintervention, and mortality. However, chEVAR patients had a more tortuous neck (61.1% vs. 16.7%, p < 0.001), while fEVAR patients had a greater neck size (29.5 ± 6.3mm vs. 24.5 ± 4.8mm, p < 0.001) and more reconstructing target arteries (2.2 ± 1.1 vs 1.3 ± 0.6, p < 0.001). fEVAR and chEVAR show similar safe and effective outcomes in well-selected hostile neck. fEVAR might be able to reconstruct multiple visceral arteries, and chEVAR seems justified in patients with poor anatomical suitability for fEVAR.

Treatment of cerebral aneurysms with the FRED Jr flow-diverting stent: A case series and meta-analysis

BackgroundWith the development of the Flow Re-Direction Endoluminal Device Junior (FRED Jr), treatment of distal aneurysms and/or aneurysms with small parent vessels has become a viable option. ObjectivesTo assess the efficacy and safety of FRED Jr in the treatment of distal aneurysms with small parent vessels. MethodsThis is a single center retrospective study and meta-analysis of patients treated with FRED Jr for intracranial aneurysms. The primary outcome was complete aneurysm occlusion at final follow-up. Secondary outcomes included stroke rates, mortality rates, need for retreatment and clinical outcomes. ResultsThere were a total of 7 patients with 7 aneurysms treated with FRED Jr. Mean aneurysm neck, width, height, and parent artery diameter were 2.6 ± 0.8 mm, 3.1 ± 0.9 mm, 2.5 ± 1.0 mm, and 1.8 ± 0.6 mm respectively. The complete occlusion rate was 57.1 % at 6 months, and favorable outcome (mRS 0–2) was observed in all patients in follow-up. Stroke complication occurred in none of the patients. Seven studies from 1360 articles were identified for inclusion in the meta-analysis, comprising 227 patients with 244 aneurysms treated with FRED Jr. Mean aneurysm height, width, neck and parent artery diameter were 6.9 ± 3.3 mm (pooled=5.6 [<0.1–11.47] mm), 6.6 ± 2.2 mm (pooled=6.6 [4.2–9.1] mm), 4.4 ± 1.4 mm (pooled=4.1 [3.3 −4.9] mm), and 2.0 ± 0.2 mm (pooled=2.1 [1.7–2.5]), respectively. At final follow-up, the pooled complete occlusion and complication rates were 69.9 % and 0 %, respectively. ConclusionFRED Jr demonstrated moderate efficacy and good safety in the treatment of distal aneurysms with small parent vessels at mid-term follow-up.

Endovascular treatment of wide-necked intracranial aneurysms using the Nautilus Intrasaccular System: initial case series of 41 patients at a single center

BackgroundEndovascular treatment of intracranial wide-necked and bifurcation aneurysms (WNBA) is technically challenging. The Nautilus Intrasaccular System is designed to provide a mechanical barrier at the aneurysm neck to support coil...

Preliminary Experience of the Surpass Streamline Flow Diverter for Large and Giant Unruptured Internal Carotid Artery Aneurysms.

As of January 2021, the Surpass Streamline (SS) is the most recently approved flow diverter in Japan. A total of 28 Japanese patients, including 9 clinical trial patients, with 28 large or giant unruptured internal carotid artery (ICA) aneurysms, underwent SS embolization at Juntendo University Hospital. Procedural failure occurred in two patients due to the difficulty to navigate the device in the tortuous parent artery. Therefore, 26 patients with 26 aneurysms were available for clinical and anatomical assessments. Patients' mean age was 62.6 years (range 46-86), and 24 patients (92.3%) were female. Mean aneurysm size and neck width were 15.4 mm and 7.7 mm, respectively, with 20 saccular and 6 fusiform aneurysms. Seven aneurysms were symptomatic due to the aneurysmal mass effect. Twenty patients underwent a 6-month follow-up angiography to evaluate the degree of occlusion. Anatomical outcomes were 12 (60%) complete occlusion (CO), 4 (20%) residual neck (RN), and 4 (20%) residual aneurysm. Favorable aneurysm occlusion consisted of CO, and RN was achieved in 16 (80.0%). There were no significant device stenoses. Aneurysmal mass effect improved in one and was unchanged in eight patients. There were three device-related complications, namely, delayed aneurysm rupture, minor ischemic stroke, and device occlusion (11.5%). One patient with minor ischemic stroke fully recovered before 30 days, and our series showed 7.7% risk of major ipsilateral stroke and neurological death at 30 days. The SS embolization for large and giant unruptured ICA aneurysms offers satisfactory anatomical and clinical outcomes with a low risk of device-related complications.

Endovascular Treatment for Aneurysms Located in the Posterior Communicating Artery (PCoA) by the Swinging-Tail Technique: A Technical Note.

Purposes: A stent-assisted coil (SAC) is a safe and effective treatment modality for some complex intracranial aneurysms, especially for wide neck aneurysms. However, some wide neck aneurysms with a tough angle and located in the posterior communicating artery (PCoA) are challenging to treat with a SAC. This study aimed to examine and discuss the swinging-tail technique for treating wide neck aneurysms located in the PCoA using a SAC by Prof. Lv. Materials and Methods: We retrospectively reviewed our institutional clinical database and identified nine patients with neck aneurysms located in the PCoA, and these patients underwent the swinging-tail technique by Prof. Lv, which is a novel technique of releasing a stent, from June 2016 to September 2021. Results: In this study, nine patients underwent SAC treatment using the swinging-tail technique by Prof. Lv. Aneurysmal complete occlusion was observed in every patient without any complications, as shown by immediate postoperative angiography. Additionally, the modified Rankin scale was monitored for clinical outcomes in the follow-up. One patient died postoperatively due to severe SAH with an intraventricular hemorrhage. Four of nine patients underwent imaging follow-up, demonstrating the complete occlusion of aneurysms; eight patients underwent clinical follow-up and achieved a favorable clinical outcome (modified Rankin scale score: 0–2). Conclusion: The SAC treatment for wide neck aneurysms located in the PCoA can be challenging for operators because of the specific location, resulting in inadequate vessel wall apposition by antegrade stenting via the ipsilateral vessel. In this circumstance, the swinging-tail technique may be a feasible and effective choice.

Risk factors and outcomes of postoperative stroke in surgical treatment for giant intracranial aneurysms

BackgroundGiant intracranial aneurysms (GIAs) are challenges for surgical treatment. Risk factors of postoperative stroke remain unclear. This study aims to investigate the predictors of postoperative stroke in GIAs and the impact of stroke on outcomes.MethodsWe performed a retrospective medical record review of patients with GIAs who received microsurgery at our institution between 2011 and 2018. Multivariate logistic regression analyses were carried out to identify risk factors for postoperative stroke. The clinical and angiographic outcomes were compared between patients with and without stroke.ResultsA total of 97 patients were included in this study. Surgical modalities included direct aneurysm neck clipping in 85 patients (87.7%), trapping with the bypass in 8 (8.2%), proximal artery ligation in 1 (1%), and bypass alone in 3 (3.1%). Postoperative stroke was found in 26 patients (26.8%). Independent factors that affect postoperative stroke were recurrent aneurysm (OR, 10.982; 95% CI, 1.976–61.045; P = 0.006) and size ≥ 3.5 cm (OR, 3.420; 95% CI, 1.133–10.327; P = 0.029). Combined perioperative mortality and morbidity was 26.8%. Follow-up was achieved from 89 patients (91.8%), with a mean follow-up period of 39 months (range 19 to 94 months). Good outcomes were observed in 75 patients (84.3%) and poor outcomes were observed in 14 patients (15.7%).ConclusionsPostoperative stroke was significantly associated with clinical outcome. Favorable outcomes can be achieved in most patients with GIAs after appropriate microsurgical modality. Recurrent aneurysm and size ≥ 3.5 cm are risk factors of postoperative stroke.

Influence of morphological parameters on hemodynamics in internal carotid artery bifurcation aneurysms

Recent advancements in medical imaging techniques have enabled the accurate identification of unruptured intracranial aneurysms. To facilitate a proper patient management strategy, it is important to develop suitable mathematical models for their rupture prediction. To this end, the development of high-fidelity computational fluid dynamics (CFD) simulations with patient-specific boundary conditions will be useful in providing reliable hemodynamic parameters. In recent review articles, researchers have pointed out that, among several clinical and image-based indicators, morphological parameters, such as aspect ratio (AR) and size ratio (SR) of the aneurysm, correlated consistently with the rupture mechanism. However, it is not clear how these morphological indicators influence the hemodynamics-based CFD predictions. In the present work, the effect of these top-ranked morphological parameters on aneurysm hemodynamics and rupture prediction is investigated. Three patient-specific models have been used for analysis with the patient-specific inlet boundary conditions. We found that with an increase in AR and SR, the maximum value of wall shear stress (WSS) near the aneurysm neck is increased. Oscillatory shear index and relative residence time values are also increased with an increase in AR and SR. Furthermore, it was observed that an aneurysm with a multilobed structure shows complex flow, low WSS, and higher residence time over the secondary lobe. The turbulent kinetic energy and vorticity near the aneurysm neck are also increased with an increase in AR and SR.

Predicting the growth of middle cerebral artery bifurcation aneurysms using differences in the bifurcation angle and inflow coefficient.

Growing intracranial aneurysms (IAs) are prone to rupture. Previous cross-sectional studies using postrupture morphology have shown the morphological or hemodynamic features related to IA rupture. Yet, which morphological or hemodynamic differences of the prerupture status can predict the growth and rupture of smaller IAs remains unknown. The purpose of this longitudinal study was to investigate the effects of morphological features and the hemodynamic environment on the growth of IAs at middle cerebral artery (MCA) bifurcations during the follow-up period. One hundred two patients with MCA M1-2 bifurcation saccular IAs who underwent follow-up for more than 2 years at the authors' institutions between 2011 and 2019 were retrospectively identified. During the follow-up period, cases involving growth of MCA IAs were assigned to the event group, and those with MCA IAs unchanged in size were assigned to the control group. The morphological parameters examined were aneurysmal neck length, dome height, aspect ratio and volume, M1 and M2 diameters and their ratio, and angle configurations among M1, M2, and the aneurysm. Hemodynamic parameters were flow rate and wall shear stress in M1, M2, and the aneurysm, including the aneurysmal inflow rate coefficient (AIRC), defined as the ratio of the aneurysmal inflow rate to the M1 flow rate. Those parameters were compared statistically between the two groups. Correlations between morphological and hemodynamic parameters were also examined. Eighty-three of 102 patients were included: 25 with growing MCA IAs (event group) and 58 with stable MCA IAs (control group). The median patient age at initial diagnosis was 66.9 (IQR 59.8-72.3) years. The median follow-up period was 48.5 (IQR 36.5-65.6) months. Both patient age and the AIRC were significant independent predictors of the growth of MCA IAs. Moreover, the AIRC was strongly correlated with sharper bifurcation and inflow angles, as well as wider inclination angles between the M1 and M2 arteries. The AIRC was a significant independent predictor of the growth of MCA IAs. Sharper bifurcation and inflow angles and wider inclination angles between the M1 and M2 arteries were correlated with the AIRC. MCA IAs with such a bifurcation configuration are more prone to grow and rupture.