PMC8168659_01
Imaging findings before and after the treatment. (a) Magnetic resonance (MR) image showing the aneurysm (9 mm, arrow) anterior to the brainstem when the patient was 68 years old, (b) MR image showing enlarged aneurysm (14 mm) when the patient was 70 years old (arrow), (c) MR image showing brainstem mass effect due to the aneurysm, (d) three-dimensional digital subtraction angiography showing a right proximal anterior inferior cerebellar artery (AICA) aneurysm (arrow) and the distal AICA (arrowheads) appearing from the aneurysm body.
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F1
Magnetic resonance imaging (MRI) revealed a 9 mm, unruptured, thrombosed aneurysm anterior to the brainstem [Figure 1a]. However, MRI at age 70 revealed increased aneurysm size (14 mm) and brainstem mass effect [Figures 1b and c]. Three-dimensional digital subtraction angiography revealed a right proximal AICA aneurysm [Figure 1d]. The distal AICA arose from the aneurysm body [Figure 1d]; therefore, we clipped the AICA just distal to the aneurysm after the OA-AICA bypass [Figures 2a-f].
Intraoperative findings. (a) Intraoperative photograph showing a right proximal anterior inferior cerebellar artery (AICA) aneurysm (asterisk), the distal AICA (arrowheads) appearing from the aneurysm body, and the branch vessel (arrow) appearing from AICA, (b) intraoperative photograph showing a distal part of the AICA (arrowheads) suitable for bypass, (c) intraoperative photograph showing occipital artery AICA bypass, (d) indocyanine green video angiography showing the adequate flow of the bypass. Retrograde filling of AICA was observed (arrow), (e) intraoperative photograph showing clipping of the AICA just distal to the aneurysm. Small branch from AICA was preserved (arrow), (f) intraoperative photograph showing the panoramic view of the surgical field after the bypass and the clipping.
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F2
The distal AICA arose from the aneurysm body [Figure 1d]; therefore, we clipped the AICA just distal to the aneurysm after the OA-AICA bypass [Figures 2a-f]. Indocyanine green video angiography showing the adequate flow of the bypass [Figure 2d].
Postoperative magnetic resonance image showing sporadic cerebellar infarctions.
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F3
Postoperative MRI demonstrated sporadic, asymptomatic cerebellar infarctions [Figure 3].
Imaging findings long after the treatment. (a) Magnetic resonance (MR) image at 6 months postoperatively showing increased aneurysm size (15 mm), (b) MR image at 12 months postoperatively showing decreased aneurysm size (12 mm), (c) MR image at 33 months postoperatively showing further decreased aneurysm size (10 mm), (d) MR image at 6 months postoperatively showing persisting brainstem mass effect, (e) MR image at 12 months postoperatively showing no brainstem mass effect, (f) MR image at 33 months postoperatively showing no brainstem mass effect.
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F4
Twelve months postoperatively, the aneurysm size was 12 mm, and the brainstem mass effect disappeared [Figures 4c and d]. Thirty-three months after surgery, the aneurysm had shrunk, and the patsient had no neurological deficits [Figures 4e and f].