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 Table of Contents  
CASE REPORT
Year : 2021  |  Volume : 9  |  Issue : 1  |  Page : 49-51

Double adjacent basilar artery fenestration with cerebellar infarct: Case report and new classification of double basilar fenestrations


Department of Neurology, Sawai Man Singh Medical College, Jaipur, Rajasthan, India

Date of Submission27-May-2021
Date of Decision14-Jun-2021
Date of Acceptance18-Jul-2021
Date of Web Publication27-Aug-2021

Correspondence Address:
Dr. Ashwini Shivayya Hiremath
Department of Neurology, Sawai Man Singh Medical College, Jaipur, Rajasthan
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jcvs.jcvs_12_21

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  Abstract 


Basilar artery (BA) fenestration is an uncommon congenital variant associated with aneurysms and posterior circulation infarcts. We present a 42-year-old male, smoker and hypertensive who came with acute onset vertigo and gait ataxia. Cerebellar signs were positive on the left side. Diffusion-weighted brain magnetic resonance imaging showed acute infarct in the left anterior inferior cerebellar artery (AICA) territory. Computed tomography angiography showed BA double adjacent fenestration of proximal segment of BA, without thrombus, dissection/aneurysm. To the best of our knowledge, only three cases of double adjacent BA fenestration have been described so far. The association between vertebro-BA fenestrations and posterior circulation stroke is controversial. It has been suggested that turbulent flow at the site of fenestration predisposes to thrombus formation, which may be cause of stroke. This rare anatomic variant of the posterior circulation is important to recognize and may have associated neurologic consequences (double BA fenestrations are rare yet known congenital variants associated with aneurysms and associated neurological implications) (double adjacent BA fenestration presenting with AICA infarct are still rarer with only three cases reported across the world).

Keywords: Anterior inferior cerebellar artery infarct, double adjacent basilar artery fenestration, new classification


How to cite this article:
Srivastava T, Hiremath AS. Double adjacent basilar artery fenestration with cerebellar infarct: Case report and new classification of double basilar fenestrations. J Cerebrovasc Sci 2021;9:49-51

How to cite this URL:
Srivastava T, Hiremath AS. Double adjacent basilar artery fenestration with cerebellar infarct: Case report and new classification of double basilar fenestrations. J Cerebrovasc Sci [serial online] 2021 [cited 2021 Dec 1];9:49-51. Available from: http://www.jcvs.com/text.asp?2021/9/1/49/324808




  Introduction Top


Arterial fenestration is a rare congenital finding that may be associated with aneurysms and can rarely dissect and bleed. There are few case reports of vertebrobasilar artery (BA) fenestration and posterior circulation stroke. There are speculations about the association between vertebro-basilar fenestrations and brainstem ischemia or infarctions, although their relationships are controversial. We describe here a rare and complicated presentation of a double adjacent BA fenestration with anterior inferior cerebellar artery (AICA) territory infarct.


  Case Report Top


A 42-year-old male presented with acute onset of vertigo and swaying on walking, towards left side. He had a history of smoking and mild hypertension but no diabetes mellitus. There was no history of diplopia, tinnitus or difficulty in deglutition. There was no history suggestive of connective tissue disorders, cerebral vasculitis and central nervous system infection. He was conscious, alert, had gait ataxia with swaying on the left side. There was no cranial nerve palsy. Cerebellar signs were positive on the left side. Complete blood counts, blood sugar, lipid profile, renal and liver functions were within normal limits. Diffusion-weighted brain magnetic resonance imaging showed acute infarct in the left cerebellar hemisphere extending up to middle cerebellar peduncle suggestive of AICA territory involvement [Figure 1]a. Computed tomography angiography revealed a BA double adjacent fenestration of proximal segment of BA, without thrombus, dissection or aneurysm [Figure 1]b and [Figure 1]c. Upper fenestrated segment was larger and at the level of AICA. Lower fenestrated segment was smaller and just distal to vertebrobasilar junction. Right AICA was normal but left AICA could not be visualized. Right vertebral artery poorly visualized may be because of thrombosis. The patient was treated with low-molecular-weight heparin and double antiplatelets initially. The patient did not give consent for cerebral digital subtraction angiography (DSA). He recovered from his neurologic deficits over 20 days and was put on prophylactic aspirin therapy without recurrence of any symptoms. The nature of illness was explained to the patient and informed consent was taken.
Figure 1: (a) Brain magnetic resonance imaging diffusion-weighted image shows left cerebellar hemisphere and middle cerebellar peduncle infarct suggestive of anterior inferior cerebellar artery territory involvement. Computed tomographic angiogram image (b and c) showing the adjacent double fenestration of the proximal basilar artery

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  Discussion Top


The frequency of BA fenestrations has been found to be 0.28%–5.26% in autopsy series,[1],[2] 0.3%–0.6% in angiographic series[3],[4] and 1.0%–2.07% in magnetic resonance angiography (MRA) series.[5],[6] BA fenestration was found in 1.29% of the 16,416 cases studied by Sogawa et al. on MRA.[7] The proximal end of the BA seems to be most prone to develop fenestration.[8],[9] The clinical significance of BA fenestration is unclear, as the autopsy incidence is only about 5%. Aneurysm is the most common association of BA fenestration.

Embryological basis of basilar artery fenestration

The BA is formed by the fusion of paired longitudinal neural arteries in 4–5 mm embryo, during its first stage. During the second stage of development at 5-week gestation, fusion of the channels gradually starts to form the BA. BA fenestrations result from incomplete fusion of these arteries and may occur anywhere along its course. The adjacent double BA fenestrations may be due to incomplete fusion at two adjacent sites. The fusion usually occurs in a craniocaudal direction. This craniocaudal direction may underlie the frequent fenestration of the BA at its proximal segment. The BA is formed by fusion of the paired longitudinal neural arteries during development, therefore, it is probably more appropriate to use the term “segmentally unfused arteries” to refer to this anatomical variant.[10]

Double fenestration and its type

In a MRA study done by Sogawa et al., the total frequency of single fenestration was 1.27% (209/16,416), while double fenestrations were found in three of 212 cases, accounting for 0.018%.[10] One case had separate fenestrations in the distal and proximal segment of the BA; two other cases had adjacent fenestrations in the proximal segment; however, both fenestrations were lateral to BA axis.[7] Stark et al. described a case of concurrent BA double fenestration with aneurysm and vertebral artery dissection.[9] The configuration of this double fenestration was similar to our case as both fenestrations were along the axis of BA. Although double fenestration is very rare, based on previous cases by Sogawa et al.[7] and Stark et al.[9] including our present case we can classify them into 2 types [Figure 2]:
Figure 2: Types of the double separate fenestrations of basilar artery. Type 1: Double separate fenestrations; one fenestration in the distal segment and the other in the proximal segment. Type 2a: Adjacent double fenestration of the proximal basilar artery; lateral to the axis of basilar artery. Type 2b: Adjacent double fenestration of the proximal basilar artery; in the axis of basilar artery

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  • Type 1: Double separate fenestrations; one fenestration in the distal segment and the other in the proximal segment
  • Type 2: Double fenestration of the proximal BA; it can be subclassified into:


    • Type 2a: Adjacent double fenestration of the proximal BA; lateral to the axis of BA
    • Type 2b: Adjacent double fenestration of the proximal BA; in the axis of BA.


Possible relation of fenestration and stroke

There have been speculations about association between vertebro-BA fenestrations and brainstem ischemia or infarctions, although their relationships are controversial.[10],[11],[12],[13],[14] El Otmani et al. reviewed the clinical, imaging findings, treatment and prognosis of 9 reported cases.[15] It has been suggested that turbulent flow at the site of fenestration predisposes patients to thrombus formation, which may be the cause of stroke in our patient. Turbulent flow also offers to explain the formation of aneurysms at the site of fenestration. In the present case, left AICA was not well visualized, which may be the result of infarct possibly due thromboembolism. It is not clear whether left PICA was supplying the left AICA territory as DSA could not be done.


  Conclusion Top


This case demonstrates a rare and complicated presentation of double adjacent BA fenestration with AICA territory infarct.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Wollschlaeger G, Wollschlaeger PB, Lucas FV, Lopez VF. Experience and result with postmortem cerebral angiography performed as routine procedure of the autopsy. Am J Roentgenol Radium Ther Nucl Med 1967;101:68-87.  Back to cited text no. 1
    
2.
Busch W. Contribution to the morphology and pathology of the basilar artery. Results of the study of 1000 brains. Arch Psychiatr Nervenkr (1970) 1966;208:326-44.  Back to cited text no. 2
    
3.
Takahashi M, Tamakawa Y, Kishikawa T, Kowada M. Fenestration of the basilar artery. Report of three cases and review of the literature. Radiology 1973;109:79-82.  Back to cited text no. 3
    
4.
Sanders WP, Sorek PA, Mehta BA. Fenestration of intracranial arteries with special attention to associated aneurysms and other anomalies. AJNR Am J Neuroradiol 1993;14:675-80.  Back to cited text no. 4
    
5.
Uchino A, Kato A, Takase Y, Kudo S. Basilar artery fenestrations detected by MR angiography. Radiat Med 2001;19:71-4.  Back to cited text no. 5
    
6.
Tanaka M, Kikuchi Y, Ouchi T. Neuroradiological Analysis of 23 cases of basilar artery fenestration based on 2280 cases of MR angiographies. Interv Neuroradiol 2006;12:39-44.  Back to cited text no. 6
    
7.
Sogawa K, Kikuchi Y, O'uchi T, Tanaka M, Inoue T. Fenestrations of the basilar artery demonstrated on magnetic resonance angiograms: An analysis of 212 cases. Interv Neuroradiol 2013;19:461-5.  Back to cited text no. 7
    
8.
Padget DH. The development of the cranial arteries in the human embryo. Contrib Embryol 1948;32:205-61.  Back to cited text no. 8
    
9.
Stark MM, Skeik N, Delgado Almandoz JE, Crandall BM, Tubman DE. Concurrent basilar artery double fenestration with aneurysm and vertebral artery dissection: Case report and literature review of rare cerebrovascular abnormalities. Ann Vasc Surg 2013;27: 21.e15-21.  Back to cited text no. 9
    
10.
Woo SR, Seo MW, Kim YH, Kwak HS, Han YM, Chung GH, et al. Extreme Duplication-type, nonseparated fenestration of the basilar artery in a patient with pontine infarction: Confirmation with virtual arterial endoscopy. J Clin Neurol 2006;2:74-7.  Back to cited text no. 10
    
11.
Scherer A, Siebler M, Aulich A. Virtual arterial endoscopy as a diagnostic aid in a patient with basilar artery fenestration and thromboembolic pontine infarct. AJNR Am J Neuroradiol 2002;23:1237-9.  Back to cited text no. 11
    
12.
Gold JJ, Crawford JR. An unusual cause of pediatric stroke secondary to congenital basilar artery fenestration. Case Rep Crit Care 2013;2013:627972.  Back to cited text no. 12
    
13.
Kloska SP, Schlegel PM, Sträter R, Niederstadt TU. Causality of pediatric brainstem infarction and basilar artery fenestration? Pediatr Neurol 2006;35:436-8.  Back to cited text no. 13
    
14.
Wu X, Lin A, Zhu J, Cai B. Basilar artery fenestration: An unusual possible cause of ischaemic stroke? BMJ Case Rep 2018;2018:bcr2017222910.  Back to cited text no. 14
    
15.
El Otmani H, Fotso V, El Moutawakil B, Rafai MA. Basilar artery fenestration and ischemic stroke: An unclear causal relationship. J Med Vasc 2020;45:62-6.  Back to cited text no. 15
    


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