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middle_cerebral_artery_m4_segment_aneurysm

Middle cerebral artery M4 segment aneurysm

Middle cerebral artery aneurysms, are 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).

Etiology

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).

Treatment

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).

Case reports

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 18).

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 19).

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 20).

1) , 4) , 5) , 20)
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) , 18)
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.
19)
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.
middle_cerebral_artery_m4_segment_aneurysm.txt · Last modified: 2017/09/05 13:44 by administrador