Middle cerebral artery M4 segment aneurysm

Middle cerebral artery M4 segment aneurysm

Middle cerebral artery aneurysms, are mainly found in the proximal and bifurcation tracts and only in the 1.1-1.7% of cases they are located in the M4 segment of the middle cerebral artery 1) 2) 3).

Generally, these aneurysms are secondary to traumatic brain injury and inflammatory or infectious diseases and only rarely they have idiopathic origin 4).

At present, only nine cases of ruptured cortical middle cerebral artery aneurysms have been described in literature 5) 6) 7) 8) 9) 10).

The patients are all males, except the case of Ricci et al. 11). The average age of the reported patients is 40 years. The size of the aneurysms is between 1 mm and 10 mm and, in most cases, they are saccular intracranial aneurysms or fusiform morphology. In five patients, the aneurysms present infectious etiology. Usually, they occur with ICH, sometimes associated with subarachnoid hemorrhage (SAH).

The endovascular treatment (EVT) has been performed in four cases, while the surgical treatment has been performed in three cases (two of trapping and one of clipping). In one patient, the infectious aneurysm has resolved spontaneously after antibiotic therapy. In all treatments performed, the patients have improved the neurologic symptoms and no residual aneurysms have been observed in the subsequent neuroradiology follow-up 12). Although surgery remains the main choice in the M4 aneurysms, because of the extremely distal location of them over the motor/somatosensory cortices, 13) Lv et al. 14) propose the use of the EVT in all types of the M4 aneurysms, especially after the surgery, when it is impossible to locate the small ruptured aneurysm.

The main difficulty of the surgery is the precise surgical localization of the small M4 aneurysms 15). An inaccurate localization of these vascular lesions may result in larger craniotomies and unnecessary arachnoid and pial dissections with possible resultant permanent neurological injuries 16).

In cases of aneurysms or arteriovenous malformations located at the sylvian point or at the posterior superior aspect of the insula, especially in dominant hemisphere, to reduce the dissection and open easily sylvian fissure, a logical path would follow the angular artery in the sylvian fissure cutting the arachnoid fibers and retracting only the tissues which are necessary to gain more exposure of the lesion 17).

A case of a ruptured dissecting pseudoaneurysm in the distal Middle cerebral artery (distal M3/proximal M4) prefrontal division in an healthy young patient (<60 years) successfully treated with a Pipeline Embolization Device. The PED was chosen both as the only vessel sparing option in the young patient as well as for its potential as a vessel sacrifice tool if the pseudoaneurysm was felt to be incompletely treated, which in this case was not necessary-though would have leveraged the thrombogenicity of the device as a therapeutic advantage 18).

2017

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

Surgery is the best choice for the treatment of ruptured M4 aneurysms with ICH in the opinion of Ricci et al., because it allows to evacuate the hematoma and to exclude the aneurysm from the intracranial circulation. In addition, we suggest both the use of the neuronavigation technique and of the indocyanine green videoangiography (ICGV) for the aneurismal surgery 19).

2007

A 41-year-old man presented with an infarction manifesting as left-sided weakness and dysarthria. Magnetic resonance angiography revealed a subacute stage infarction in the right MCA territory and complete occlusion of the right ICA. Angiography demonstrated aneurysmal dilatation of the M4 segment of the right MCA. Surgery was performed to prevent hemorrhage from the aneurysm. The aneurysm was proximally clipped guided by Navigation-CT angiography and flow to the distal MCA was restored by superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis 20).

2005

A 20-year-old man with an intracerebral haemorrhage due to a ruptured aneurysm, which arose from a penetrating artery of the distal middle cerebral artery (MCA; M4 segment). Excision of the aneurysm was successfully achieved via a right pterional approach. The follow-up angiogram demonstrated filling of the parent vessel and no residual aneurysm. This report illustrates the angiographical finding of a penetrating artery aneurysm of the distal MCA and summarizes the previous reports to discuss their pathological and clinical characteristics 21).


1) , 4) , 5) , 21)

Ahn JY, Han IB, Joo JY. Aneurysm in the penetrating artery of the distal middle cerebral artery presenting as intracerebral haemorrhage. Acta Neurochir (Wien). 2005 Dec;147(12):1287-90; discussion 1290. Epub 2005 Aug 29. PubMed PMID: 16133768.
2) , 8) , 14)

Lv N, Zhou Y, Yang P, Li Q, Zhao R, Fang Y, Xu Y, Hong B, Zhao W, Liu J, Huang Q. Endovascular treatment of distal middle cerebral artery aneurysms: Report of eight cases and literature review. Interv Neuroradiol. 2016 Feb;22(1):12-7. doi: 10.1177/1591019915617317. Epub 2015 Dec 3. Review. PubMed PMID: 26637241; PubMed Central PMCID: PMC4757379.
3)

Elsharkawy A, Lehečka M, Niemelä M, Billon-Grand R, Lehto H, Kivisaari R, Hernesniemi J. A new, more accurate classification of middle cerebral artery aneurysms: computed tomography angiographic study of 1,009 consecutive cases with 1,309 middle cerebral artery aneurysms. Neurosurgery. 2013 Jul;73(1):94-102; discussion 102. doi: 10.1227/01.neu.0000429842.61213.d5. PubMed PMID: 23615110.
6)

Horiuchi T, Tanaka Y, Takasawa H, Murata T, Yako T, Hongo K. Ruptured distal middle cerebral artery aneurysm. J Neurosurg. 2004;100:384–8.
7)

Lee SM, Park HS, Choi JH, Huh JT. Ruptured mycotic aneurysm of the distal middle cerebral artery manifesting as subacute subduralhematoma. J Cerebrovasc Endovasc Neurosurg. 2013;15:235–40.
9) , 13) , 15) , 16)

Raza SM, Papadimitriou K, Gandhi D, Radvany M, Olivi A, Huang J. Intra-arterial intraoperative computed tomography angiography guided navigation: a new technique for localization of vascular pathology. Neurosurgery. 2012 Dec;71(2 Suppl Operative):ons240-52; discussion ons252. doi: 10.1227/NEU.0b013e3182647a73. PubMed PMID: 22858682.
10) , 11) , 12) , 19)

Ricci A, Di Vitantonio H, De Paulis D, Del Maestro M, Raysi SD, Murrone D, Luzzi S, Galzio RJ. Cortical aneurysms of the middle cerebral artery: A review of the literature. Surg Neurol Int. 2017 Jun 13;8:117. doi: 10.4103/sni.sni_50_17. eCollection 2017. PubMed PMID: 28680736; PubMed Central PMCID: PMC5482160.
17)

Ausman JI, Diaz FG, Malik GM, Tomecek F. A new microsurgical approach to cerebrovascular lesions of the sylvian point: report of two cases. Surg Neurol. 1990 Jul;34(1):48-51. PubMed PMID: 2360163.
18)

Berwanger RP, Hoover MC, Scott JA, DeNardo AJ, Amuluru K, Payner TD, Kulwin CG, Sahlein DH. The Use of a Pipeline Embolization Device for Treatment of a Ruptured Dissecting Middle Cerebral Artery M3/M4 Aneurysm: Challenges and Technical Considerations. Neurointervention. 2022 Apr 7. doi: 10.5469/neuroint.2022.00045. Epub ahead of print. PMID: 35385900.
20)

Lee SH, Bang JS. Distal Middle Cerebral Artery M4 Aneurysm Surgery Using Navigation-CT Angiography. J Korean Neurosurg Soc. 2007 Dec;42(6):478-80. doi: 10.3340/jkns.2007.42.6.478. Epub 2007 Dec 20. PubMed PMID: 19096593; PubMed Central PMCID: PMC2588183.

Unruptured intracranial aneurysm treatment score

Unruptured intracranial aneurysm treatment score

see also PHASES score.

The unruptured intracranial aneurysm treatment score (UIATS) was published in April 2015 as a multidisciplinary consensus regarding the treatment of unruptured intracranial aneurysms (UIA).

Etminan et al. endeavored to develop an unruptured intracranial aneurysm treatment score (UIATS) model that includes and quantifies key factors involved in clinical decision-making in the management of UIAs and to assess agreement for this model among specialists in Unruptured intracranial aneurysm (UIA) management and research.

An international multidisciplinary (neurosurgery, neuroradiology, neurology, clinical epidemiology) group of 69 specialists was convened to develop and validate the UIATS model using a Delphi consensus. For internal (39-panel members involved in the identification of relevant features) and external validation (30 independent external reviewers), 30 selected UIA cases were used to analyze agreement with UIATS management recommendations based on a 5-point Likert scale (5 indicating strong agreement). Interrater agreement (IRA) was assessed with standardized coefficients of dispersion (vr) (vr = 0 indicating excellent agreement and vr* = 1 indicating poor agreement).

The UIATS accounts for 29 key factors in UIA management. Agreement with UIATS (mean Likert scores) was 4.2 (95% confidence interval [CI] 4.1-4.3) per reviewer for both reviewer cohorts; agreement per case was 4.3 (95% CI 4.1-4.4) for panel members and 4.5 (95% CI 4.3-4.6) for external reviewers (p = 0.017). Mean Likert scores were 4.2 (95% CI 4.1-4.3) for interventional reviewers (n = 56) and 4.1 (95% CI 3.9-4.4) for noninterventional reviewers (n = 12) (p = 0.290). Overall IRA (vr*) for both cohorts was 0.026 (95% CI 0.019-0.033).

This novel UIA decision guidance study captures an excellent consensus among highly informed individuals on UIA management, irrespective of their underlying specialty. Clinicians can use the UIATS as a comprehensive mechanism for indicating how a large group of specialists might manage an individual patient with a UIA 1)   


The Unruptured Intracranial Aneurysm Treatment Score (UIATS) offers support for clinical decision making and has been shown to correlate with real-life decisions in clinical practice. However, there is no data concerning the correlation of patient Unruptured intracranial aneurysm outcome and UIATS. Patients presenting to the Department of Neurosurgery,University Hospital Leipzig, outpatient clinic between January 1st, 2014, and December 31st, 2017 were retrospectively analyzed. They recorded the Extended Glasgow Outcome Scale (GOS-E) for the longest possible follow-up, the choice of treatment, complications, and UIATS recommendation. They included 221 patients with 322 UIA. 124 (38.5 %) UIA were observed and 198 (61.5 %) were occluded, of which 62 (31.3 %) underwent open surgery and 136 (68.7 %) were treated endovascularly. Spearman’s rank correlation between the treatment choice and conclusive UIATS recommendation was 0.362 (p < 0.001). If UIATS was inconclusive, there were significantly more treatment-associated deteriorations (10/66 versus 7/132, p = 0.020). Otherwise, UIATS was not significantly associated with outcome. Therefore, the treatment choice for UIA remains an individual decision. However, inconclusive UIATS must trigger vigilance and may be a negative prognostic marker for complications 2).


A tertiary center with focus on vascular neurosurgery, aimed to investigate whether there treatment decision-making in patients with UIA has been in accordance with the published UIATS. A retrospective analysis of patients admitted to the center with UIA was performed. UIATS was applied to all identified UIA. Three decision groups were defined: (a) UIATS favoring treatment, (b) UIATS favoring observation, and © UIATS inconclusive. These results were then compared to our clinical decisions. Spearman’s rank-order correlation (ρ) was run to determine the relationship between the UIATS and our clinical decisions. Cases of discrepancies between UIATS and our clinical decisions were then examined for complications, defined as periprocedural adverse events in treated aneurysms, or aneurysm rupture in untreated aneurysms. Ninety-three patients with 147 UIA were included. A total of 118/147 (80.3%) UIA were treated. In 70/118 (59.3%), UIATS favored treatment, in 18/118 (15.3%), it was inconclusive, and in 30/118 (25.4%), it favored observation. A total of 29/147 (19.7%) UIA were not treated. In 15/29 (51.7%), UIATS favored observation, in 9/29 (31%), it favored treatment, and in 5/29 (17.2%), it was inconclusive (ρ = 0.366, p < 0.01). Discrepancies between UIATS and our clinical decisions did not correlate with complications (ρ = 0.034, p = 0.714). Our analysis shows that our more intuitive clinical decision-making has been in line with UIATS. Our treatment decisions did not correlate with an increased rate of complications 3).


The purpose of the study of Ravindra et al. was to compare the unruptured intracranial aneurysm treatment score (UIATS) recommendations with the real-world experience in a quaternary academic medical center with a high volume of patients with unruptured intracranial aneurysms (UIAs).

All patients with UIAs evaluated during a 3-year period were included. All factors included in the UIATS were abstracted, and patients were scored using the UIATS. Patients were categorized in a contingency table assessing UIATS recommendation versus real-world treatment decision. The authors calculated the percentage of misclassification, sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve. RESULTS A total of 221 consecutive patients with UIAs met the inclusion criteria: 69 (31%) patients underwent treatment and 152 (69%) did not. Fifty-nine (27%) patients had a UIATS between -2 and 2, which does not offer a treatment recommendation, leaving 162 (73%) patients with a UIATS treatment recommendation. The UIATS was significantly associated with treatment (p < 0.001); however, the sensitivity, specificity, and percentage of misclassification were 49%, 80%, and 28%, respectively. Notably, 51% of patients for whom treatment would be recommended by the UIATS did not undergo treatment in the real-world cohort and 20% of patients for whom conservative management would be recommended by UIATS had intervention. The area under the ROC curve was 0.646.

Compared with the authors’ experience, the UIATS recommended overtreatment of UIAs. Although the UIATS could be used as a screening tool, individualized treatment recommendations based on consultation with a cerebrovascular specialist are necessary. Further validation with longitudinal data on rupture rates of UIAs is needed before widespread use 4).


1)

Etminan N, Brown RD Jr, Beseoglu K, Juvela S, Raymond J, Morita A, Torner JC, Derdeyn CP, Raabe A, Mocco J, Korja M, Abdulazim A, Amin-Hanjani S, Al-Shahi Salman R, Barrow DL, Bederson J, Bonafe A, Dumont AS, Fiorella DJ, Gruber A, Hankey GJ, Hasan DM, Hoh BL, Jabbour P, Kasuya H, Kelly ME, Kirkpatrick PJ, Knuckey N, Koivisto T, Krings T, Lawton MT, Marotta TR, Mayer SA, Mee E, Pereira VM, Molyneux A, Morgan MK, Mori K, Murayama Y, Nagahiro S, Nakayama N, Niemelä M, Ogilvy CS, Pierot L, Rabinstein AA, Roos YB, Rinne J, Rosenwasser RH, Ronkainen A, Schaller K, Seifert V, Solomon RA, Spears J, Steiger HJ, Vergouwen MD, Wanke I, Wermer MJ, Wong GK, Wong JH, Zipfel GJ, Connolly ES Jr, Steinmetz H, Lanzino G, Pasqualin A, Rüfenacht D, Vajkoczy P, McDougall C, Hänggi D, LeRoux P, Rinkel GJ, Macdonald RL. The unruptured intracranial aneurysm treatment score: a multidisciplinary consensus. Neurology. 2015 Sep 8;85(10):881-9. doi: 10.1212/WNL.0000000000001891. Epub 2015 Aug 14. PubMed PMID: 26276380; PubMed Central PMCID: PMC4560059.
2)

Wende T, Kasper J, Wilhemy F, Prasse G, Quäschling U, Haase A, Meixensberger J, Nestler U. Comparison of the unruptured intracranial aneurysm treatment score recommendations with clinical treatment results – A series of 322 aneurysms. J Clin Neurosci. 2022 Feb 9;98:104-108. doi: 10.1016/j.jocn.2022.01.038. Epub ahead of print. PMID: 35151060.
3)

Hernández-Durán S, Mielke D, Rohde V, Malinova V. The application of the unruptured intracranial aneurysm treatment score: a retrospective, single-center study. Neurosurg Rev. 2018 Feb 1. doi: 10.1007/s10143-018-0944-2. [Epub ahead of print] PubMed PMID: 29388120.
4)

Ravindra VM, de Havenon A, Gooldy TC, Scoville J, Guan J, Couldwell WT, Taussky P, MacDonald JD, Schmidt RH, Park MS. Validation of the unruptured intracranial aneurysm treatment score: comparison with real-world cerebrovascular practice. J Neurosurg. 2017 Oct 6:1-7. doi: 10.3171/2017.4.JNS17548. [Epub ahead of print] PubMed PMID: 28984518.

Unruptured anterior communicating artery aneurysm rupture risk

Unruptured anterior communicating artery aneurysm rupture risk

Although the research on the risk factors of anterior communicating artery aneurysm has made great progress, the independent effect of each risk factor on the rupture of AComA aneurysm is controversial among different studies. For this answer Xie et al. will present the results employing the random effects model. Quality assessment of the included studies will be evaluated using the Newcastle–Ottawa Scale. Statistical analyses will be performed using Stata16 (Stata Corporation, College Station, TX, USA) software.The findings of this study will be submitted to peer-reviewed journals for publication. This systematic review will provide evidence to determine the risk factors that affect the rupture of the AComA aneurysm and quantify their independent effects 1).


Ma et al. found that larger size, greater size ratio, larger flow angle, irregular shape, and smoking of the patient were associated with the rupture of ACoA aneurysms based on univariate analysis. Size ratio (OR = 3.890, P = 0.003), irregular shape (OR = 1.068, P = 0.001), flow angle (OR = 1.054, P = 0.001), and current smoking (OR = 4.435, P = 0.009) were the strongest factors related to ruptured ACoA aneurysms based on multivariate logistic regression analysis. The areas under the curves for the flow angle and size ratio were 0.742 (95% CI 0.646-0.838; P = 0.001) and 0.736 (95% CI 0.621-0.796; P = 0.001), respectively. The strongest risk factors for rupture include size ratio, irregular shape, flow angle, and current smoking. These features should be taken into consideration to aid in the prediction of the rupture risk of ACoA aneurysms 2).


Multiple logistic regression model revealed that A1 dominance [odds ratio (OR) 3.034], an irregular shape (OR 3.358), and an aspect ratio ≥1.19 (AR; OR 3.163) increased the risk of rupture, while cerebral atherosclerosis (OR 0.080), and mean diameters ≥2.48 mm (OR 0.474) were negatively correlated with ACoAA rupture. Incorporating these five factors, the ROC analysis revealed that the threshold value of the multifactors was one, the sensitivity was 88.3%, and the specificity was 66.0%. The scoring model is a simple method that is based on A1 dominance, irregular shape, aspect ratio, cerebral atherosclerosis, and mean diameters from CTA and is of great value in the prediction of the rupture risk of ACoAAs 3).


According to the International Study of Unruptured Intracranial Aneurysms (ISUIA), anterior circulation (AC) aneurysms of <7 mm in diameter have a minimal risk of rupture. It is general experience, however, that anterior communicating artery (AcoA) aneurysms are frequent and mostly rupture at <7 mm. Bijlenga et al. found that AC aneurysms are not a homogenous group. Aneurysms between 4 and 7 mm located in AcoA or distal anterior cerebral artery present similar rupture odds to posterior circulation aneurysms. Intervention should be recommended for this high-risk lesion group 4).


For Matsukawa et al. the anterior projection of an ACoA aneurysm may be related to rupturing. The authors would perhaps recommend treatment to patients with unruptured ACoA aneurysms that have an anterior dome projection, a bleb(s), and a size ≥ 5 mm 5).


Aneurysms found unruptured in the ACoA show a risk of rupture twice as high as that of other intracranial aneurysms (95% confidence interval, 1.29-3.12). It is the first time this fact has been demonstrated based on the follow-up of unruptured aneurysms.

When deciding whether to operate on UIAs located in the ACoA, surgeons should consider their higher risk of rupture 6).


1)

Xie Y, Tian H, Xiang B, Li D, Liu YZ, Xiang H. Risk factors for anterior communicating artery aneurysm rupture: A protocol for systematic review and meta-analysis. Medicine (Baltimore). 2021 Dec 3;100(48):e28088. doi: 10.1097/MD.0000000000028088. PMID: 35049234.
2)

Ma X, Yang Y, Liu D, Zhou Y, Jia W. Demographic and morphological characteristics associated with rupture status of anterior communicating artery aneurysms. Neurosurg Rev. 2020 Apr;43(2):589-595. doi: 10.1007/s10143-019-01080-w. Epub 2019 Jan 31. PMID: 30706157.
3)

Wang GX, Wang S, Liu LL, Gong MF, Zhang D, Yang CY, Wen L. A Simple Scoring Model for Prediction of Rupture Risk of Anterior Communicating Artery Aneurysms. Front Neurol. 2019 May 31;10:520. doi: 10.3389/fneur.2019.00520. PMID: 31214103; PMCID: PMC6554323.
4)

Bijlenga P, Ebeling C, Jaegersberg M, Summers P, Rogers A, Waterworth A, Iavindrasana J, Macho J, Pereira VM, Bukovics P, Vivas E, Sturkenboom MC, Wright J, Friedrich CM, Frangi A, Byrne J, Schaller K, Rufenacht D; @neurIST Investigators. Risk of rupture of small anterior communicating artery aneurysms is similar to posterior circulation aneurysms. Stroke. 2013 Nov;44(11):3018-26. doi: 10.1161/STROKEAHA.113.001667. Epub 2013 Jul 30. PMID: 23899912.
5)

Matsukawa H, Uemura A, Fujii M, Kamo M, Takahashi O, Sumiyoshi S. Morphological and clinical risk factors for the rupture of anterior communicating artery aneurysms. J Neurosurg. 2013 May;118(5):978-83. doi: 10.3171/2012.11.JNS121210. Epub 2012 Dec 14. PMID: 23240701.
6)

Mira JM, Costa FA, Horta BL, Fabião OM. Risk of rupture in unruptured anterior communicating artery aneurysms: meta-analysis of natural history studies. Surg Neurol. 2006;66 Suppl 3:S12-9; discussion S19. doi: 10.1016/j.surneu.2006.06.025. PMID: 17081844.
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