Fenestrated A1 in Ruptured Anterior Communicating Artery Aneurysm: A Case Report

There is a lot of variation around the anterior communicating artery (Acom) and various classification systems have been quoted many times in literatures. Here we have reported a rare case of a 52year-old woman who had ruptured Acomartery aneurysm. The angiography also showed a fenestration of the A1 segment of anterior cerebral artery. nomalous variation of the anterior communicating artery (Acom) has been described many times in the literature and various classifications have been quoted. As there is a lot of variation around the Acom artery and because of its location and projection of the aneurysm, Acom artery aneurysm is most difficult to operate among other anterior circulating aneurysms. Here we have reported the case of a rare fenestration of the A1 segment of anterior cerebral artery associated with ruptured Acom artery aneurysm. Methods and Materials:

nomalous variation of the anterior communicating artery (Acom) has been described many times in the literature and various classifications have been quoted. 1 As there is a lot of variation around the Acom artery and because of its location and projection of the aneurysm, Acom artery aneurysm is most difficult to operate among other anterior circulating aneurysms. 2 Here we have reported the case of a rare fenestration of the A1 segment of anterior cerebral artery associated with ruptured Acom artery aneurysm.

Case description:
A 52-year-old right-handed woman presented to our emergency department with a history of sudden onset of severe headache for 5 hours, and it was associated with multiple episodes of vomiting. There was no history of loss of consciousness, trauma, and fever. On arrival her blood pressure was 180/110mm of Hg, she was opening eyes to speech, verbally confused, and obeying command.
Her pupils were bilateral 3mm reacting to light and was moving all the four limbs. CT scan of her head showed diffuse subarachnoid hemorrhage more localized in perioptic cistern and anterior interhemispheric region. Her CT angiography showed Acom artery aneurysm pointing anteriorly and there was a fenestration of the right A1 segment of the anterior cerebral artery. She underwentright pterional craniotomy and clipping of aneurysm. The osteoplastic bone flap was raised with three burr holes, and the lesser wing of the sphenoid bone was flushed down to the meningo-orbital band, which was detached. Dura was opened curvilinearly and was based inferiorly. Optico-carotid cistern was opened to release CSF from the basal cistern.
Microscopic dissection was carried out to identify bilateral A1, including the right fenestrated part, it required the resection of a part of the gyrus-rectus and finally, bilateral A2 were also identified. During the dissection around the neck of the aneurysm, it got ruptured so a tentative clipping was done after placing the temporary clips in bilateral A1. And finally, the permanent clips were placed just at the neck preserving all the proximal and distal parent vessels. The patency of the vessels was confirmed by visual inspection. Postoperatively she was extubated after 7 hours and then she gradually recovered to her previous health. There was no new added focal neurological deficit postoperatively.

Discussion:
Acomartery aneurysms are one of the most difficult aneurysms to clip among other anterior circulating aneurysms. 2 The difficulty is because of its location behind the gyrus rectus of the frontal lobe, various projection of the aneurysm, and occasionally due to various vascular anomalies that coexist with the aneurysm. 2,3 Various types of vascular anomalies around the Acom artery that have been described in the literature are typical, atypical, azygous, accessory A2, and fenestrated Acom. 1,4,5 Along with these variations, A1 fenestrations were also described occasionally in different literatures. 6,7,8 Similarly, in this case, we have found an fenestrated A1 segment of anterior cerebral artery associated with anterior pointing Acom aneurysm. 9,10 Clipping of Acom artery aneurysm required proper identification of bilateral A1, A2, and Acom artery so that the clip occluding the neck of the aneurysm will not incorporate those important vessels. 2,3 In the presence of accessory A1, it possesses the risk of missing one of the A1 and hence has a risk of misplacement of aneurysm clip. Beside of challenge in clipping, there is also added risk of aneurysm rupture intraoperatively during dissection around the aneurysm. In our case also the aneurysm got ruptured during the last stage of dissection after the identification of proximal and distal vessels. These were dealt with tentative clipping followed by proper neck isolation and final permanent clipping. The patency of surrounding vessels was confirmed by microscopic visual inspection.
The Projection of aneurysm is also an important factor during the placement of the clip. 11 Inferior and anterior pointing Acom aneurysm can be usually clipped with straight aneurysm clips, whereas superior pointing aneurysms might require tandem clipping. The posterior pointing Acom aneurysms are difficult ones requiring angle fenestrated clips, where the parent vessel is passed through the fenestration and anterior thalamic perforators need to be preserved during occlusion of the aneurysm neck. In our case, it was anterior pointing Acom aneurysm, so it was possible to clip the neck of aneurysm with a single simple straight aneurysm clip preserving the proximal and distal flow in parent vessels.

Conclusion:
The presence of accessory A1 can be a rare type of anomalous presentation that may be associated with a ruptured Acom aneurysm.