Development of the Circle of Willis Score (COWS) to help guide decision making during acute tandem occlusion treatment: Preliminary analysis.

BACKGROUND: Acute tandem occlusions (TOs) are challenging to treat. Although acute carotid stenting of the proximal lesion is well tolerated, there are certain situations when the practitioner may be wary of acute stenting (bleeding concerns). OBJECTIVE: The purpose of this study was to retrospectively study patients with tandem occlusions who had re-occlusion of the extracranial ICA and develop a Circle of Willis Score (COWS) to help predict which patients could forego acute stenting. METHODS: This is a retrospective review of TO patients with a persistent proximal occlusion following intervention (either expected or unexpected). Pre intervention CTA and intraoperative DSA were reviewed, and each patient was assigned a score 2 (complete COW), 1a (patent A1-Acomm-A1), 1p (patent Pcomm), or 0 (incomplete COW). Findings from the DSA took precedence over the CTA. Two cohorts were created, the complete COW cohort (COWS 2) versus the incomplete COW cohort (COWS 1a,1p, or 0). Angiographic outcomes were assessed using the mTICI score (2b-3) and clinical outcomes were assessed using discharge mRS (good outcome mRS 0-3). RESULTS: Of 68 TO cases, 12 had persistent proximal occlusions. There were 5/12 (42 %) patients in the complete COW cohort, and 7/12 (58 %) in the incomplete COW cohort (5/12 with scores of 1a/1p and 2/12 with a score of 0). In the complete COW cohort, there were 2 ICA-ICA and 3 ICA-MCA occlusions. In the incomplete COW cohort, there was one ICA-ICA occlusion and 6 ICA-MCA occlusions. LKW-puncture was shorter in the complete COW cohort (208 min vs. 464 min, p = 0.16). Successful reperfusion was higher in the complete COW cohort (100 % vs. 71 %). There was a trend toward better clinical outcomes in the complete COW cohort (80 % vs 29 %, p = 0.079). CONCLUSION: The COWS is a simple score that may help predict a successful clinical outcome without proximal revascularization when concerned about performing an acute carotid stent during TO treatment. Evaluation in larger TO cohort is warranted.

Flow control in the middle cerebral artery during thrombectomy: the effect of anatomy, catheter size and tip location.

BACKGROUND: Catheter size, location and circle of Willis anatomy impact the flow conditions during interventional stroke therapy. The aim of the study was to systematically investigate the influence of these factors on flow control in the middle cerebral artery by means of a computational model based on 100 patients with stroke who received endovascular treatment. METHODS: The dimensions of the cervical and intracranial cerebral arteries of 100 patients who received endovascular mechanical thrombectomy for acute ischemic stroke were measured and a three-dimensional model of the circle of Willis was created based on these data. Flow control in the middle cerebral artery with variations in catheter size, catheter location and configurations of collateral vessels was determined using a computational model. A total of 48 scenarios were analyzed. RESULTS: Flow reversal with a distal aspiration catheter alone was not possible in the internal carotid artery and only sometimes possible in the middle cerebral artery (14 of 48 cases). The Catalyst 7 catheter was more often successful in achieving flow reversal than Catalyst 5 or 6 catheters (p<0.001). In a full circle of Willis anatomy, flow reversal was almost never possible. The absence of one or more communicating arteries significantly influenced flow direction compared with the full anatomy with all communicating arteries present (p=0.028). CONCLUSION: Choosing the biggest possible aspiration catheter and locating it in the middle cerebral artery significantly increases the chances of successful flow control. Flow through the collaterals may impair the flow, and circle of Willis anatomy should be considered during aspiration thrombectomy.

Assessment of Primary Collateral Grades Based on the Integrity of Willis' Circle: Predicting the Prognosis of Acute Intracranial Internal Carotid Artery Occlusion Before Thrombectomy.

OBJECTIVE: Endovascular mechanical thrombectomy (EVMT) has shown significant efficacy in improving neurological functions in patients with intracranial internal carotid artery occlusion (IICAO), but its clinical outcomes are variable. We examined the relationship between favorable clinical outcomes after EVMT in IICAO and a set of predictors. METHODS: In this retrospective study, 189 patients with IICAO treated by EVMT at 3 centers from November 2015 to December 2020 were included and analyzed. Non-contrast computed tomography and computed tomography angiography were evaluated on admission. The morphology of IICAO was categorized into Ia, Ib, L, or T types, depending on the involvement of the posterior communicating artery origin, proximal anterior cerebral artery, and middle cerebral artery. The Willis' circle was categorized as integrated or compromised Willis' circle. In combination with the involvement of the IICAO and the integrity of Willis' circle, we used the primary collateral grade (PCG) to describe the presence of functional Willisian collaterals. Baseline data including demographics, characteristics, vascular risk factors, and initial National Institutes of Health Stroke Scale scores were collected. Hemorrhagic transformation was evaluated using the 24-hour non-contrast computed tomography after EVMT. Favorable outcomes based on modified Rankin scale, were defined as 0-2 at 90 days. RESULTS: A total of 189 patients were included (median age, 69 years; 126 male [66.7%]). 104 patients [55.0%] showed reperfusion after EVMT, but 72 patients [38.1%] achieved favorable outcomes at 90 days. The mortality rate of type Ib was significantly higher than that with type Ia (χ2 = 14.21, P = 0.001). The outcome with different structure of Willis' circle was not statistically different between the 2 groups. A multivariate logistic regression analysis showed that IICAO T-type (odds ratio, 0.028 [95% confidence interval: 0.323-3.829], P = 0.042) and PCG 2 (odds ratio 9.427[95% confidence interval:1.863-47.698], P = 0.007) were predictors of favorable outcomes. CONCLUSIONS: Evaluation of PCG by determining the type of IICAO and the integrity of Willis' circle may serve as a valuable indicator for the prognosis and as an essential reference for screening patients before EVMT.

Variations of perforating arteries of anterior communicating artery in cases with anterior communicating artery aneurysms: a cadaveric anatomical study.

PURPOSE: In terms of postoperative morbidity and mortality, preservation of the perforating arteries branching from the anterior communicating artery (ACoA) during clipping is particularly imperative in patients with ACoA aneurysm. In the present study, we aimed to investigate whether perforating arteries originated from ACoA were pushed away in a different location in patients with ACoA aneurysm. Furthermore, if they did so, we aimed to identify the direction in which they were dislocated and how the perforating arteries could be preserved during clipping. METHODS: Herein, we categorized 40 brains obtained from cadavers into two groups. The first (n = 26) and second (n = 14) groups included cases without and with ACoA aneurysms, respectively. After completing the preparation procedure, the brains were dissected using surgical microscope and the relevant anatomical region was examined and photographed. Finally, statistical analyses were performed on the data and the results were documented. RESULTS: In the aneurysms with posterior and superior projections, the perforators appeared to be pushed away inferiorly and were frequently noted at the anteroinferior part of the aneurysm neck. Most of the cases, where one of the A1s was larger at one side, the perforating arteries arose from the larger A1 side. CONCLUSION: The mortality and morbidity associated with damage to the perforators can be reduced by approaching the patient from the dominant A1 side and pursuing the perforators primarily at the anteroinferior part of the aneurysm neck in the aneurysms with superior and posterior projections.

Mechanical thrombectomy beyond the circle of Willis: efficacy and safety of different techniques for M2 occlusions.

BACKGROUND: M2 segment occlusions represent approximately one-third of non-lacunar ischemic stroke and can lead to permanent neurological deficits. Various techniques are available for mechanical thrombectomy beyond the circle of Willis, but data evaluating their effectiveness and safety are lacking. METHODS: A retrospective review of patients with ischemic stroke undergoing mechanical thrombectomy for M2 occlusions from 13 centers in North American and Europe was performed. Tandem or multiple-territory occlusions were excluded. The primary outcome was 90-day modified Rankin Scale and reperfusion rates across stent-retriever, direct aspiration and combined techniques. RESULTS: There were 465 patients (mean age 71.48±14.03 years, 53.1% female) with M2 occlusions who underwent mechanical thrombectomy. Stent-retriever alone was used in 133 (28.6%), direct aspiration alone in 93 (20.0%) and the combined technique in 239 (51.4%) patients. Successful reperfusion was achieved with the combined technique in 198 (82.2%; OR 2.6 (1.1-6.9)), with stent-retriever alone in 112 (84.2%; OR 9.2 (1.9-44.6)) and with direct aspiration alone in 62 (66.7%; referencecategory). Intraprocedural subarachnoid hemorrhages (iSAH) were 36 (7.7%) and were more likely to occur in patients treated with the stent-retrievers (OR 5.0 (1.1-24.3)) and combined technique (OR 4.6 (1.1-20.9)). Good clinical outcome was achieved in 260 (61.8%) patients, while 59 (14.0%) patients died. Older age, higher baseline NIHSS (National Institutes of Health Stroke Scale), parenchymal hemorrhage and iSAH were associated with poor outcome while successful recanalization and higher baseline ASPECTS (Alberta Stroke Program Early CT Score) were associated with good outcome. No differences were found among the three techniques in terms of clinical outcome. CONCLUSION: Stent-retrievers and a combined approach for M2 occlusions seem more effective than direct aspiration, but with higher rates of iSAH. This leads to no detectable difference in clinical outcome at 3 months.

Seven Microaneurysms: Description of an Experimental Rodent Model for Neurovascular Training.

AIM: To demonstrate the microsurgical procedures, and to evaluate the feasibility of living models of experimental neurovascular training by developing new complex vascular exercises mimicking the most common intracranial aneurysms. MATERIAL AND METHODS: The procedures were performed under a Zeiss (OPMI pico f170) microscope using basic microsurgery instruments, 10/0 Nylon and blue Polypropylene micro-sutures. We selected adult albino Wistar rats weighing between 258 and 471g each. Seven different aneurysm types were created using carotid, jugular, cava, aorta and femoral vessels. RESULTS: Seven types of aneurysm were designed and created in the rat with a high-medium successful rate. There are differences in terms of realism and the difficulty of performance, according to the different types: lateral wall, bifurcation, top of the basilar, fusiform, fusiform + involved branch, Anterior Communicating Artery (ACoA) and giant. The steps and technical issues to produce these exercises are described. CONCLUSION: We show the feasibility of creating several types of aneurysm using different vessels in a rodent model. Training on these models help to improve microsurgical skills, allowing safe practice for neurosurgeons in all stages of their career.

Ruptured Infundibular dilatation of the posterior communicating artery.

OBJECTIVE: An infundibulum of the posterior communicating artery (PcomA) or infundibular dilatation (ID) is considered to be a benign anatomical variant. However, some evidence suggests that ID is a pre-aneurysmal state. This case series presents cases of ruptured IDs and aneurysms originating from the IDs. METHODS: Between April 2002 and June 2020, 1337 patients were treated for aneurysmal subarachnoid hemorrhage (SAH). Among them, 7 patients with ruptured PcomA IDs were identified. Rupture IDs of the PcomA were categorized into 1) direct rupture of IDs, and 2) rupture of aneurysms originating from IDs. The clinical and radiographic factors were retrospectively reviewed. RESULTS: Two patients experienced direct rupture of IDs, while the other 5 patients presented with ruptured aneurysms originating from IDs. The 2 patients with direct rupture of IDs at presentation were relatively younger (< 50 years), while the other 5 patients with ruptured aneurysms originating from IDs were over 70 and had a history of aneurysmal SAH due to other intracranial aneurysms. Ruptured IDs were treated with microsurgery or endovascular treatment. There were no complications related to the procedure for securing ruptured IDs. Five (71.4%) patients showed favorable outcomes. One patient with initial Hunt and Hess grade 4 died due to initial brain damage with cerebral vasospasm and medical complications. CONCLUSIONS: ID of the PcomA rarely causes SAH with or without aneurysm formation. Thus, patients with IDs of the PcomA should be carefully followed up for a long period, especially those with a history of aneurysmal SAH.

Clinical and Hemodynamic Features in Moyamoya Disease with Intracranial Aneurysms.

OBJECTIVE: Intracranial aneurysms (IAs) are occasionally associated with moyamoya disease (MMD). The purpose of this study was to elucidate differences between patients with MMD with and without IAs and differences between patients with IAs at different locations. METHODS: Between May 2012 and December 2017, consecutive patients with MMD were enrolled in a retrospective single-center study. IAs were classified as circle of Willis (CoW) or peripheral aneurysms according to the anatomic location. Clinical characteristics and hemodynamic parameters were collected and analyzed. A hemispheric analysis was performed for Suzuki stage and computed tomography perfusion parameters. RESULTS: The study included 31 patients with MMD with IAs and 279 patients with MMD without IAs. The patients with IAs had more severe neurological dysfunction, more advanced Suzuki stage, and less hemodynamic dysfunction than the patients without IAs (P < 0.05). Of patients with MMD with IAs, 17 had CoW aneurysms, and 13 had peripheral aneurysms. Patients with CoW aneurysms were older and had more advanced Suzuki stage than patients with peripheral aneurysms (P < 0.05). CONCLUSIONS: Patients with MMD with IAs had different clinical and hemodynamic features compared with patients with MMD without IAs. CoW aneurysms and peripheral aneurysms may occur at different stages of MMD, which may explain their differences in anatomical location, type of hemorrhage, and treatment strategy.

Long-term stability of fusiform dilatation of the internal carotid artery following surgery adjacent to the circle of Willis: report of 2 cases.

Fusiform dilatation of the internal carotid artery (FDCA) is a known postoperative imaging finding after craniopharyngioma resection. FDCA has also been reported following surgery for other lesions in the suprasellar region in pediatric patients and is thought to be due to trauma to the internal carotid artery (ICA) wall during tumor dissection. Here, the authors report 2 cases of pediatric patients with FDCA. Case 1 is a patient in whom FDCA was visualized on follow-up scans after total resection of a craniopharyngioma; this patient's subsequent scans and neurological status remained stable throughout a 20-year follow-up period. In case 2, FDCA appeared after resection and fenestration of a giant arachnoid cyst in a 3-year-old child, with 6 years of stable subsequent follow-up, an imaging finding that to the authors' knowledge has not previously been reported following surgery for arachnoid cyst fenestration. These cases demonstrate that surgery involving dissection adjacent to the carotid artery wall in pediatric patients may lead to the development of FDCA. On very long-term follow-up, this imaging finding rarely changes and virtually all patients remain asymptomatic. Neurointerventional treatment of FDCA in the absence of symptoms or significant late enlargement of the arterial ectasia does not appear to be indicated.

Comparative Analysis of Pterional, Supraorbital, Extended Supraorbital, and Transtubercular-Transplanum Approaches for Exposing the Anterior Communicating Artery Complex: A Cadaveric Study.

OBJECTIVE: We aimed to quantify and compare surgical exposure and freedom at the anterior communicating artery (ACoA) complex using pterional (PT), supraorbital (SO), extended supraorbital withorbital osteotomy (SOO), and endonasal endoscopic transtubercular-transplanum (EEATT) approaches. METHODS: Right-sided PT, SO, SOO, and EEATT approaches were performed using 10 cadaveric heads. Surgical exposure and freedom (horizontal and vertical attack angle) at the ACoA complex were measured. The farthest clipping distance from ACoA to A1 (precommunicating segment of the anterior cerebral artery)/A2 (postcommunicating segment of the anterior cerebral artery) was also quantified. RESULTS: There was a significantly greater exposure length of right A1 in the PT approach (12.20 ± 2.48 mm) compared with the EEATT approach (9.52 ± 2.09 mm; P = 0.029). Among the 4 approaches, EEATT provided the shortest clipping distance for right A1 (6.56 ± 1.33 mm; P = 0.001) and the longest clipping distance for right A2 (3.36 ± 1.24 mm; P = 0.003). SO, SOO, and PT approaches (2.9 ± 0.9) had more observations on perforators from ACoA than did the EEATT approach (2.0 ± 0.66; P = 0.029). The EEATT approach (50.90 ± 17.45 mm2) provided better exposure of the superior part of the ACoA complex compared with the SO approach (29.37 ± 17.27 mm2; P = 0.05). PT and SOO approaches provided the greatest horizontal (36.88° ± 5.85°) and vertical (19.37° ± 4.70°) attack angle, respectively. CONCLUSIONS: The SO, SOO, and PT approaches provided a better hemilateral view of the ACoA complex and similar surgical exposure, whereas the EEATT approach offered greater exposure in the upper part of the ACoA complex, with relatively limited exposure of perforators from ACoA and surgical freedom. The EEATT approach can play a role in exposure of lesion involving the ACoA complex.

Competitive flow diversion of multiple P1 aneurysms: proposed classification.

We report the case of a patient with subarachnoid hemorrhage and three aneurysms arising from the posterior communicating artery (Pcomm)-P1 complex, treated with endovascular coiling and competitive flow diversion. The largest and likely ruptured Pcomm aneurysm was treated with traditional coiling. Two smaller potentially ruptured aneurysms arose from the distal right posterior cerebral artery (PCA) P1 segment. After a failed attempt to treat with conventional flow diversion across the PCA-P1 segment, the P1 aneurysms were successfully treated with competitive flow diversion distal to the PCA-P1 segment from Pcomm to the P2 segment. Over 12 months, competitive flow diversion redirected flow to the right PCA territory via the internal carotid artery-Pcomm-P2, reducing the size of the PCA-P1 segment and obliterating the P1 aneurysms. Competitive flow diversion treatment should be considered for aneurysms occurring at the circle of Willis when traditional methods are not feasible. Herein, we introduce a novel classification for competitive flow diversion treatment.

Clinical and morphological risk factors for the recurrence of anterior communicating artery aneurysms after clipping or coiling.

BACKGROUND: The aim of this study was to evaluate clinical and morphological factors associated with recurrence in anterior communicating artery (AcomA) aneurysms after clipping or coiling. METHODS: We retrospectively reviewed the clinical and radiologic features of consecutive 214 patients with AcomA aneurysms treated between January 2012 and December 2016 in a single tertiary institute. Univariate and multivariate analyses were performed to identify the relationship between clinical and morphological variables and recurrence. RESULTS: Of 214 patients, 166 were unruptured aneurysms and 109 were treated with coiling. Overall recurrence rate was 13% (28 out of 214 aneurysms) during mean 36.9 ± 18.4-month follow-up. Multivariate logistic regression analysis showed that size greater than 10 mm (OR = 5.651; 95% CI, 1.317-24.242; p = 0.020), smoking (OR = 3.474; 95% CI, 1.342-8.996; p = 0.010), coiling (OR = 2.98; 95% CI, 1.005-8.832; p = 0.049), and anterior direction of aneurysm (OR = 3.77; 95% CI, 1.12-12.66; p = 0.032) were significantly associated with recurrence of AcomA aneurysms after treatment. CONCLUSIONS: The results of this study demonstrated that coiling, large aneurysm, anterior direction, and smoking history may be independent risk factors for the recurrence of AcomA aneurysms. Therefore, careful follow-up should be needed especially in large AcomA aneurysms with anterior direction after coiling.

Flow modification on the internal carotid artery bifurcation region and A1 segment after M1-internal carotid artery flow diverter deployment.

BACKGROUND: Clinical and hemodynamic consequences of flow diverters extending from the M1 to the internal carotid artery (ICA), covering the A1 segment, have rarely been investigated. We aimed to provide angiographic and clinical data about flow modifications on the covered A1. METHODS: Consecutive patients receiving M1-ICA flow diverters for unruptured aneurysms were collected from our prospective database (2014-2020). RESULTS: 42 A1 arteries covered with a single device were studied. All patients had an angiographic detected contralateral flow from the anterior communicating artery (AcomA). Immediately after flow diversion, 20 (47.6%) covered A1 showed slow flow. During a mean angiographic follow-up of 14 months, 13 (31%) and 22 (52.3%) A1 arteries were occluded and narrowed, respectively. Flow changes were asymptomatic in all cases. Vascular risk factors, sex, oversized compared with not oversized stents, immediate A1 slow flow, age, diameter of the A1, length of follow-up, and platelet inhibition rate were tested as prognosticators of A1 occlusion. Length of the angiographic follow-up was the only predictor of A1 occlusion (p=0.005, OR=3, CI=1.4 to 6.7). There were two device related ischemic events with a 2.3% rate of morbidity (one basal ganglia infarct after coverage of the M1 perforators and one transient acute instent thrombosis). CONCLUSIONS: Covering the A1 segment during M1-ICA flow diversion seems relatively safe, if the contralateral flow is assured by the AcomA. Approximately 31% and 52% of the covered A1 showed asymptomatic occlusions and narrowing, respectively. The likelihood of flow modification was proportional to the length of follow-up. Morbidity associated with flow diversion in the ICA terminus region was 2.3%.

Detachable balloon embolization as the preferred treatment option for traumatic carotid-cavernous sinus fistula?

OBJECTIVE: The purpose of the study was to investigate the treatments and outcomes of patients with traumatic carotid-cavernous sinus fistula (TCCF). METHODS: All patients diagnosed with TCCF at our institution from January 2013 to December 2018 and meeting the inclusion/exclusion criteria were included in the study. RESULTS: A total of 24 patients were included in this study. Of them, 21 (87.5%) were treated with detachable balloon embolization, 1 (4%) with coil embolization, 1 (4%) with balloon-assisted coil embolization, and 1 (4%) with balloon-assisted coil and glue embolization. Among the 21 patients treated with detachable balloon embolization, 10 underwent double-balloon technique embolization including double-detachable balloon embolization (n = 6) and balloon-assisted detachable balloon embolization (n = 4). The fistulas in 17 patients (17/21, 81%) were successfully occluded after the first attempt of detachable balloon embolization, while those in the remaining 4 patients were occluded after a second surgery due to TCCF recurrence or pseudoaneurysm development. Preservation of the internal carotid artery (ICA) was observed in 19 cases after the first treatment by detachable balloon embolization (19/21, 90.4%). ICA was occluded in the remaining two patients, as revealed by a complete angiographic evaluation of the circle of Willis. All patients achieved complete resolution of ocular and orbital manifestations as well as pulsatile bruit, except for three patients whose oculomotorius and/or abducens remained paralyzed during the follow-up period. CONCLUSION: Although several endovascular treatment options are available for TCCF, the detachable balloon embolization is still the preferred method of TCCF, as evidenced in our study. Furthermore, double balloon technique, an improvement upon the conventional detachable balloon embolization, is extremely safe and can effectively treat patients with refractory TCCF.

Effect of age on outcomes and practice patterns for patients with anterior communicating artery aneurysms.

BACKGROUND: With widespread utilization of noninvasive imaging, small unruptured anterior communicating artery (AcoA) aneurysms are increasingly detected in the general population, particularly in elderly patients. We investigated the association between age and clinical characteristics and outcomes of patients with unruptured AcoA aneurysms. METHODS: Between January 2008 and May 2016, information on 179 consecutive patients with unruptured AcoA aneurysms was obtained and included demographic data, aneurysm features, risk factors for formation and rupture, treatment type, complications, and follow-up information. A 2-tailed t test was used for continuous data and the chi-square test for categorical variables. Statistical significance was set at P value < 0.05. RESULTS: There were 76 patients 65 and older (42.5%) and 103 younger than 65 (57.5%). Conservative management was more common in older patients (67.1% vs. 41.7%, P=0.001). Endovascular treatment was more commonly used in the older population (80% vs. 61% of the treated aneurysms in older and younger group, P=0.16). Treatment-related complications were 8% but resulted in permanent neurological deficits in one patient (1.2%). Among conservatively treated aneurysms, three (3.2%) ruptured at follow-up resulting in patient death in two cases (2.4%). All three ruptures occurred in elderly patients. CONCLUSIONS: With a modern approach that emphasizes endovascular therapy, especially in older individuals, unruptured AcoA aneurysms can be treated with a very low morbidity. Among patients with small aneurysms for which treatment was not deemed indicated or necessary, the rate of rupture at follow-up was not negligible, with 5.8% of older patients experiencing bleeding from the aneurysm.

Can sectioning the posterior communicating artery be predicted with computed tomography angiography in the microsurgical clipping of basilar apex aneurysms?

BACKGROUND: Microsurgical clipping is a viable option for managing high-riding basilar apex aneurysms (BAXs) using a transsylvian approach. Cutting the posterior communicating artery (PCoA) at the perforator-free zone provides sufficient exposure of BAX, although it is not always safe. The aim was to qualitatively predict sectioning of the interfering PCoA by using preoperative computed tomographic angiography (CTA). METHODS: A virtual trajectory from the lesser sphenoid wing to the neck of the aneurysm was simulated on CTA in 19 consecutive patients operated on BAX aneurysms from 2013 to 2018. The angles on CTA resembled the typical view through the extended pterional craniotomy. Next, the ipsilateral PCoA was tracked from the internal carotid to its end at the posterior cerebral artery in the trajectory. RESULTS: The opticocarotid and carotid-oculomotor window served as the corridors for entering the interpeduncular fossa in 16 patients (84.2%) and in 3 patients (15.8%), respectively. The PCoA was intentionally cut during nine surgeries and preserved in 10 of them. The PCoA was cut more often when positioned toward the cranial base and more medially in the corridor; both the Kernel density analysis and the data points representing the position of the PCoA supported this finding (p < 0.01). The CTA-based position of either ends of the PCoA in the trajectory did not differ between cut and not-cut groups (p = 0.19-0.96). Aneurysm projection, rupture, size, PCoA diameter, length, and other distances on CTA were not related to the sectioning of PCoA (p > 0.05). CONCLUSIONS: The probability of PCoA sectioning is higher when the PCoA is positioned medially and closer to the cranial base. If the anatomical course of the PCoA is recognized beforehand, it can contraindicate surgery. Preoperative CTA-based planning facilitates the surgery of BAX aneurysms. Therefore, CTA can make microsurgical clipping planning more predictable for the neurosurgeon and safer for the patient.

Quantitative measurement of the surgical freedom for anterior communicating artery complex-a comparative study between the frontotemporal pterional and supraorbital craniotomy; a laboratory study.

OBJECTIVE: To quantitatively measure surgical degree of freedom (SDF) to the anterior communicating artery (AComA) complex via removal of the orbital rim. Comparisons of SDF quadrants were made between a supraorbital and standard frontotemporal pterional craniotomy according to the surgeons' geometric microscope compass-based views. METHODS: Eleven latex-injected formalin-fixed cadaveric heads; 14 sides (eight unilateral and three bilateral) were dissected. Standard frontotemporal pterional and subsequent supraorbital craniotomy approaches were conducted in each specimen. Point "0" was allocated as a point 1 cm distal to the ipsilateral A1 and A2 junction of AComA. The tip of a 10-cm long pointer was used to locate point 0. The base of the pointer stick was maneuvered outside the craniotomy in eight compass directions, with the most peripheral points expressed as target points 1-8. The center of this octagon was attributed point C. A pyramid was established by connecting the points 0, C, and 2 neighboring target points. A frameless stereotaxic instrument was used as a three-dimensional digitizer to measure pyramid volume. Each neighboring two pyramids form a hexagonal cone and was expressed as a surgical freedom quadrant (cm3). The quadrants are depicted counterclockwise (surgeons view) as orbital-nasal, vertex-nasal, vertex-temporal, and orbital-temporal. RESULTS: Total SDF obtained via supraorbital and pterional approaches were 122.8 ± 109.66 and 159.94 ± 93.65, respectively (mean ± SD cm3; supraorbital < pterional by 30.2%). Supraorbital to pterional, in the orbital-nasal quadrant was 21.9 ± 35.5 and 13.04 ± 8.7, vertex-nasal 31.3 ± 28.5 and 16.7 ± 13.7, vertex-temporal 39.5 ± 42.14 and 60.4 ± 4.7, and orbital-temporal 30.14 ± 42.14 and 70.01 ± 42.14, respectively (mean ± SD cm3). In the vertex-nasal quadrant, the supraorbital approach provides a 47.3% increase in SDF compared to the standard frontotemporal pterional craniotomy approach. CONCLUSION: Given that the AComA complex is located more nasally and the surgeon's view is more vertex, we propose that a supraorbital craniotomy allows a more contralateral portion of the AComA complex to be visualized during dissection.

Treatment of a Fusiform Anterior Cerebral Artery Aneurysm by Remodeling the Circle of Willis with Flow Diversion: A Novel Technical Note.

BACKGROUND: Fusiform aneurysms are challenging lesions to manage given their poorly understood natural history and lack of a distinct neck. Historically, they have been treated surgically but endovascular management has recently evolved as a viable alternative. In this case, we describe a novel flow diversion technique for treatment of a fusiform anterior cerebral artery (ACA) aneurysm by jailing the compromised parent vessel obtaining endovascular aneurysm trapping. METHODS: A 25-year-old man underwent brain magnetic resonance imaging and magnetic resonance angiography for workup of a headache, which revealed a fusiform right ACA A1 segment aneurysm. The patient subsequently underwent catheter digital subtraction angiography, which confirmed a 9 × 5.5 mm fusiform right ACA A1 segment aneurysm. The patient elected to undergo endovascular treatment. A Pipeline Embolization Device (Medtronic, Dublin, Ireland) was placed from the right anterior cerebral artery to the right middle cerebral artery, thereby jailing the right ACA A1 segment. RESULTS: At 6-month follow-up, the patient was asymptomatic and his headache had resolved. An angiogram was obtained, showing patency of the Pipeline Embolization Device and near complete occlusion of the right ACA A1 segment. The right ACA A2 segment remained patent via collateral flow through the anterior communicating artery. These findings were confirmed on magnetic resonance imaging. The patient remained asymptomatic for the duration of the follow-up. CONCLUSIONS: This case illustrates the efficacy of the Pipeline Embolization Device for treatment of a fusiform anterior circulation aneurysm via remodeling the circle of Willis.

Experience with FRED junior flow diverter in treatment of cerebral aneurysms at or distal to the circle of Willis.

This retrospective study was aimed at assessing our results of endovascular management using the FRED junior flow diverter in cerebral aneurysms at or distal to the circle of Willis. 12 patients with 15 small cerebral vessel aneurysms at or distal to the circle of Willis underwent endovascular treatment using the FRED junior flow diverter at two tertiary care centres in Mumbai, India. 12 of the 15 aneurysms were unruptured, one was treated in an acutely ruptured setting, while two, which had presented with SAH were initially treated with balloon assisted coiling and later treated in a staged manner with a flow diverter. Technical success was 100% in all 15 deployments. Deployments were made across angles ranging from 45° to 180°. There was no stroke/TIA/death in any of the cases, which were unruptured. The O'Kelly-Marotta (OKM) staging was used to analyze angiographic follow up (at least one post procedure angiogram) which was available in 8 patients (10 aneurysms). OKM D & C was seen in 80% of the aneurysms on follow up angiograms. The treatment of small vessel cerebral aneurysms at or distal to the Circle of Willis using a dedicated flow diverter (FRED Jr.) is both technically feasible and highly efficacious.