Endovascular treatment of an aneurysm arising from the minor limb of an upper basilar artery fenestration: illustrative case

Ayaka Matsuo Department of Neurosurgery, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan; and

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Takeshi Hiu Department of Neurosurgery, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan; and

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Hiroaki Otsuka Departments of Neurosurgery and

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Atsushi Miyazaki Radiology, National Hospital Organization Nagasaki Medical Center, Nagasaki, Japan

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Wataru Haraguchi Departments of Neurosurgery and

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Ichiro Kawahara Departments of Neurosurgery and

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Tomonori Ono Departments of Neurosurgery and

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Tsuyoshi Izumo Department of Neurosurgery, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan; and

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Takayuki Matsuo Department of Neurosurgery, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan; and

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Keisuke Tsutsumi Departments of Neurosurgery and

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BACKGROUND

An aneurysm arising in an upper basilar artery (BA) fenestration is extremely rare. The authors reported a case involving successful endovascular treatment of an aneurysm arising from the minor limb of an upper BA fenestration.

OBSERVATIONS

A 65-year-old woman presented with an incidentally detected upper BA aneurysm arising from the minor limb of an upper BA fenestration. The irregularly shaped aneurysm was 6.0 × 2.7 mm in diameter, and the minor limb had several perforators. The aneurysm was nearly completely occluded with a catheter-assisted technique. The authors preserved both limbs of the BA fenestration. The postoperative course was uneventful, and the patient had an excellent clinical course with no neurological deficits or aneurysmal recanalization.

LESSONS

The case is the first report of an unruptured aneurysm arising at the minor limb of an upper BA fenestration. In this case, the authors preserved the minor limb with endovascular treatment. The authors believe catheter-assisted coil embolization to be a feasible endovascular technique in such cases.

ABBREVIATIONS

BA = basilar artery; MR = magnetic resonance

BACKGROUND

An aneurysm arising in an upper basilar artery (BA) fenestration is extremely rare. The authors reported a case involving successful endovascular treatment of an aneurysm arising from the minor limb of an upper BA fenestration.

OBSERVATIONS

A 65-year-old woman presented with an incidentally detected upper BA aneurysm arising from the minor limb of an upper BA fenestration. The irregularly shaped aneurysm was 6.0 × 2.7 mm in diameter, and the minor limb had several perforators. The aneurysm was nearly completely occluded with a catheter-assisted technique. The authors preserved both limbs of the BA fenestration. The postoperative course was uneventful, and the patient had an excellent clinical course with no neurological deficits or aneurysmal recanalization.

LESSONS

The case is the first report of an unruptured aneurysm arising at the minor limb of an upper BA fenestration. In this case, the authors preserved the minor limb with endovascular treatment. The authors believe catheter-assisted coil embolization to be a feasible endovascular technique in such cases.

ABBREVIATIONS

BA = basilar artery; MR = magnetic resonance

A basilar artery (BA) fenestration rarely occurs in the upper part of the artery. Furthermore, an aneurysm arising from an upper BA fenestration is extremely rare.

We herein report the first case of an unruptured aneurysm occurring in the minor limb of an upper BA fenestration that was treated using a catheter-assisted technique with a good clinical outcome.

Illustrative Case

A 65-year-old woman was admitted to our hospital for evaluation of an upper BA aneurysm that had been incidentally detected on magnetic resonance (MR) angiography. Digital subtraction angiography showed an aneurysm measuring 6.0 × 2.7 mm in diameter with an irregular shape, located proximal to the minor limb of the upper BA fenestration with several perforating arteries (Fig. 1). The aneurysm had an anterior bleb. Endovascular coil embolization was selected for treatment of the aneurysm.

FIG. 1.
FIG. 1.

Anteroposterior view (A) of three-dimensional rotational angiography of the right vertebral angiogram showing an aneurysm on the minor limb of an upper BA fenestration. Magnified anteroposterior view of panel A (B) and magnified right lateral view of panel A (C). The aneurysm projected anteroposteriorly and was 6.0 × 2.7 mm in diameter. Several perforators (arrows) originated from the minor limb. The anterior bleb was identified.

One week before the treatment, dual antiplatelet therapy using aspirin and clopidogrel was started. With the patient under general anesthesia, a 6-Fr guiding catheter (Roadmaster, Goodman) was placed in the right vertebral artery. Because the diameter of the minor limb was only 1.1 mm and had several perforating arteries, we used a catheter-assisted procedure to preserve the minor limb. We inserted a microcatheter (Excelsior SL-10, preshaped 45, Stryker Neurovascular) into the minor limb using a microguidewire (CHIKAI, Asahi Intecc Co. Ltd.) and then inserted another microcatheter (Excelsior SL-10, preshaped 90) into the aneurysm (Fig. 2A). Anticoagulation therapy was performed during the procedures. The aneurysm was embolized with detachable coils assisted by the microcatheter (Excelsior SL-10, preshaped 45; Fig. 2B). Postoperative angiography revealed near-complete occlusion of the aneurysm and preservation of both limbs of the fenestrated BA (Fig. 3). Diffusion-weighted MR imaging showed a small high-signal lesion in the right cerebellar hemisphere. The postoperative course was uneventful, and the patient was discharged with no neurological deficits. Dual antiplatelet therapy was continued for 1 month, followed by aspirin for 1 year. Two years after the endovascular treatment, the aneurysm was not recanalized.

FIG. 2.
FIG. 2.

Roadmap imaging of right vertebral artery angiogram, anteroposterior views. A: Another microcatheter was placed in the aneurysm after the first microcatheter was inserted into the minor limb. B: The aneurysm was embolized with a catheter-assisted technique.

FIG. 3.
FIG. 3.

Right vertebral angiography. Anteroposterior view (A) after endovascular embolization and three-dimensional rotational angiography and anteroposterior view (B) of the right vertebral artery showing near-complete occlusion of the aneurysm. Both limbs were also preserved (B).

Discussion

Observations

The reported incidence of BA fenestration ranges from 1.0% to 2.1% based on MR angiography1,2 and from 0.3% to 1.1% based on digital subtraction angiography.3–5 Among the three portions of the BA (upper, middle, and lower), the most frequent site of BA fenestration is the lower BA near the vertebrobasilar artery junction.1,3,6 In previous MR angiography studies, only 3 (1.4%) of 2122 and 2 (2.9%) of 695 BA fenestrations were located at the upper part of the BA. One proposed explanation of the rarity of this location is the characteristic development of the primitive BA, which progresses by fusion of paired primitive longitudinal neural arteries, usually in the craniocaudal direction.1–3,7,8

An aneurysm arising from an upper BA fenestration is extremely rare. We identified only 15 cases in the literature,3,9–16 including 1 case in the middle-upper part17 and our case (Table 1). Very few unruptured aneurysms have been reported, and ours is the fifth such case. In most cases, the aneurysmal neck was located at the proximal end of the fenestration. To our knowledge, this is the first case of an unruptured aneurysm arising from the minor limb of an upper BA fenestration.

TABLE 1.

Characteristics of patients with aneurysms associated with a fenestrated distal BA

Case No.Authors & YearAge (yrs)/SexPresentationSize of Aneurysm (mm)Location of Aneurysm NeckPerforating Arteries From Parent LimbTreatmentPrognosis
1Crompton, 196212ND/NDIncidentalNDProximal end of fenestrationNDNDND
2Hemmati & Kim, 19791335/MSAH3Proximal end of fenestrationNDConservativeGR
3Andrew et al., 19861454/FSAHNDDistal end of fenestrationNDWrappingGR
4Imaizumi et al., 19961532/MSAH3Proximal end of fenestrationNDClippingGR
5Tasker & Byrne, 19971041/MSAH2Proximal end of fenestrationNDCoil embolizationND
6Fukushima et al., 20001659/FSAH4Proximal end of fenestrationNDClippingSD
7Islak et al., 2002330/MSAH7Proximal end of fenestrationNDCoil embolizationGR
8Islak et al., 2002341/FIncidental6Proximal end of fenestrationNDCoil embolizationGR
9Im et al., 2007651/FIncidental9, 2 (kissing aneurysms)Proximal end of fenestrationSmall perforating arteries from both limbsCoil embolizationGR
10Juszkat et al., 2009926/MSAH2.6 × 1.7Proximal end of fenestrationNDCoil embolizationGR
11Trivelate et al., 20161152/FSAHNDProximal end of fenestrationNDCoil/balloon remodelingND
12Trivelate et al., 20161154/FSAHNDProximal end of fenestrationNDCoil/stentND
13Trivelate et al., 20161151/FIncidentalNDProximal end of fenestrationNDCoil/stentND
14Zhang et al., 20191737/FSAHNDMinor limb of fenestrationNDCoil/stentND
15Matsuo et al., 202265/FIncidental6.0 × 2.7Minor limb of fenestrationSome perforating arteries from minor limbCoil/double catheterGR

GR = good recovery; ND = not described; SAH = subarachnoid hemorrhage; SD = severe disability.

Endovascular management has become the first option for treating these aneurysms.11 Among 15 cases, 10 BA fenestration aneurysms were treated with endovascular procedures using simple coiling, balloon remodeling, or stent-assisted techniques (Table 1). Only our case was treated with catheter-assisted coil embolization. This technique was adopted to maintain the patency of the minor limb, which had a tiny diameter, instead of the balloon-assist or stent-assist technique. The aneurysm was successfully embolized with this method, preserving both limbs. In cases involving a vascular structure such as that in the present case, the herein-described technique may be considered an option for treatment. Zhang et al.17 reported that occlusion of the minor limb is relatively safe when no perforating arteries are present. However, Im et al.6 reported a case of small perforators originating from both the major and minor limbs of an upper BA fenestration. In the present case, the minor limb of an upper BA fenestration had several perforating arteries. Even the minor limb of the fenestrated BA should be preserved whenever an angiographically visible branch originates from the limb.

Lessons

Aneurysms at upper BA fenestrations are extremely rare. The present case is the first report of an unruptured aneurysm arising from the minor limb of an upper BA fenestration with several perforating arteries. Using a catheter-assisted technique, we attained nearly complete occlusion of the aneurysm while preserving the minor limb, which had a tiny diameter. We believe that this method is a feasible endovascular procedure for aneurysms at upper BA fenestrations with a small parent artery, as in this case.

Acknowledgments

We thank Angela Morben, DVM, ELS, from Edanz for editing a draft of this manuscript.

This study was funded by a Grant-in-Aid for Scientific Research to T.H. (no. 20K09328).

Disclosures

The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

Author Contributions

Conception and design: Hiu, Matsuo, Haraguchi, Kawahara. Acquisition of data: Hiu, Matsuo. Analysis and interpretation of data: Hiu, Matsuo, Otsuka, Haraguchi. Drafting the article: Hiu, Matsuo. Critically revising the article: Hiu, Matsuo, Ono, Izumo. Reviewed submitted version of manuscript: Hiu, Matsuo, Ono, Tsutsumi. Approved the final version of the manuscript on behalf of all authors: Hiu. Statistical analysis: Matsuo. Administrative/technical/material support: Hiu, Miyazaki. Study supervision: Hiu, Izumo, Matsuo, Tsutsumi.

References

  • 1

    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(suppl 1):3944.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    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(4):461465.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Islak C, Kocer N, Kantarci F, Saatci I, Uzma O, Canbaz B. Endovascular management of basilar artery aneurysms associated with fenestrations. AJNR Am J Neuroradiol. 2002;23(6):958964.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    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(1):6887.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Uchino A, Saito N, Okada Y, et al. Fenestrations of the intracranial vertebrobasilar system diagnosed by MR angiography. Neuroradiology. 2012;54(5):445450.

  • 6

    Im SH, Kwon BJ, Jung C, Seo HS, Lee DH, Han MH. Coil embolization of “kissing aneurysms” associated with distal basilar artery fenestration. Clin Neurol Neurosurg. 2007;109(2):210213.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Komiyama M. Essential anatomical knowledge for neurointervention: functional neurovascular anatomy. Jpn J Neurosurg. 2004;13(2): 116125.

  • 8

    Tanaka S, Tokimura H, Makiuchi T, et al. Clinical presentation and treatment of aneurysms associated with basilar artery fenestration. J Clin Neurosci. 2012;19(3):394401.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Juszkat R, Nowak S, Moskal J, Kociemba W, Zarzecka A. Endovascular treatment of basilar artery aneurysms associated with distal fenestration. A case report. Interv Neuroradiol. 2009;15(1):109111.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Tasker AD, Byrne JV. Basilar artery fenestration in association with aneurysms of the posterior cerebral circulation. Neuroradiology. 1997;39(3):185189.

  • 11

    Trivelato FP, Abud DG, Nakiri GS, et al. Basilar artery fenestration aneurysms: endovascular treatment strategies based on 3D morphology. Clin Neuroradiol. 2016;26(1):7379.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12

    Crompton MR. The pathology of ruptured middle-cerebral aneurysms with special reference to the differences between the sexes. Lancet. 1962;2(7253):421425.

  • 13

    Hemmati M, Kim KS. A ruptured aneurysm at the basilar artery fenestration. Radiology. 1979;130(1):174.

  • 14

    Andrews BT, Brant-Zawadzki M, Wilson CB. Variant aneurysms of the fenestrated basilar artery. Neurosurgery. 1986;18(2):204207.

  • 15

    Imaizumi T, Saito K, Kobayashi T, Sakamoto Y, Komeichi T. Saccular aneurysm associated with fenestration of the distal segment of basilar artery. Article in Japanese. No Shinkei Geka. 1996;24(7):639642.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Fukushima T, Takagi T, Fuse T. A ruptured aneurysm on the distal basilar artery fenestration: a case report. Jpn J Neurosurg. 2000;9(5):381385.

  • 17

    Zhang D, Wang H, Feng Y, Xu N. Fenestration deformity of the basilar artery trunk with an aneurysm: a case report. Medicine (Baltimore). 2019;98(28):e16393.

  • Collapse
  • Expand
  • FIG. 1.

    Anteroposterior view (A) of three-dimensional rotational angiography of the right vertebral angiogram showing an aneurysm on the minor limb of an upper BA fenestration. Magnified anteroposterior view of panel A (B) and magnified right lateral view of panel A (C). The aneurysm projected anteroposteriorly and was 6.0 × 2.7 mm in diameter. Several perforators (arrows) originated from the minor limb. The anterior bleb was identified.

  • FIG. 2.

    Roadmap imaging of right vertebral artery angiogram, anteroposterior views. A: Another microcatheter was placed in the aneurysm after the first microcatheter was inserted into the minor limb. B: The aneurysm was embolized with a catheter-assisted technique.

  • FIG. 3.

    Right vertebral angiography. Anteroposterior view (A) after endovascular embolization and three-dimensional rotational angiography and anteroposterior view (B) of the right vertebral artery showing near-complete occlusion of the aneurysm. Both limbs were also preserved (B).

  • 1

    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(suppl 1):3944.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    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(4):461465.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Islak C, Kocer N, Kantarci F, Saatci I, Uzma O, Canbaz B. Endovascular management of basilar artery aneurysms associated with fenestrations. AJNR Am J Neuroradiol. 2002;23(6):958964.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    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(1):6887.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Uchino A, Saito N, Okada Y, et al. Fenestrations of the intracranial vertebrobasilar system diagnosed by MR angiography. Neuroradiology. 2012;54(5):445450.

  • 6

    Im SH, Kwon BJ, Jung C, Seo HS, Lee DH, Han MH. Coil embolization of “kissing aneurysms” associated with distal basilar artery fenestration. Clin Neurol Neurosurg. 2007;109(2):210213.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Komiyama M. Essential anatomical knowledge for neurointervention: functional neurovascular anatomy. Jpn J Neurosurg. 2004;13(2): 116125.

  • 8

    Tanaka S, Tokimura H, Makiuchi T, et al. Clinical presentation and treatment of aneurysms associated with basilar artery fenestration. J Clin Neurosci. 2012;19(3):394401.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Juszkat R, Nowak S, Moskal J, Kociemba W, Zarzecka A. Endovascular treatment of basilar artery aneurysms associated with distal fenestration. A case report. Interv Neuroradiol. 2009;15(1):109111.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Tasker AD, Byrne JV. Basilar artery fenestration in association with aneurysms of the posterior cerebral circulation. Neuroradiology. 1997;39(3):185189.

  • 11

    Trivelato FP, Abud DG, Nakiri GS, et al. Basilar artery fenestration aneurysms: endovascular treatment strategies based on 3D morphology. Clin Neuroradiol. 2016;26(1):7379.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12

    Crompton MR. The pathology of ruptured middle-cerebral aneurysms with special reference to the differences between the sexes. Lancet. 1962;2(7253):421425.

  • 13

    Hemmati M, Kim KS. A ruptured aneurysm at the basilar artery fenestration. Radiology. 1979;130(1):174.

  • 14

    Andrews BT, Brant-Zawadzki M, Wilson CB. Variant aneurysms of the fenestrated basilar artery. Neurosurgery. 1986;18(2):204207.

  • 15

    Imaizumi T, Saito K, Kobayashi T, Sakamoto Y, Komeichi T. Saccular aneurysm associated with fenestration of the distal segment of basilar artery. Article in Japanese. No Shinkei Geka. 1996;24(7):639642.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Fukushima T, Takagi T, Fuse T. A ruptured aneurysm on the distal basilar artery fenestration: a case report. Jpn J Neurosurg. 2000;9(5):381385.

  • 17

    Zhang D, Wang H, Feng Y, Xu N. Fenestration deformity of the basilar artery trunk with an aneurysm: a case report. Medicine (Baltimore). 2019;98(28):e16393.

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