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Updated: Sep 18, 2026
Minimally Invasive Thumb-sized Pterional Craniotomy for Surgical Clip Ligation of Unruptured Anterior Circulation Aneurysms
Published on: August 11, 2015
Surgical Strategy Selection for Posteriorly Directed Anterior Communicating Artery Aneurysms based on 3D Morphometric
Mohamed Mohsen1, Tamer Hassan1, Ahmed Sultan1
1Department Of Neurosurgery, Alexandria University School of Medicine, Azarita medical campus, Alexandria 21514, Egypt.
Background:
Posteriorly directed anterior communicating artery (Acom A) aneurysms are surgically challenging due to their deep midline location and intimate proximity to A2 segments, hypothalamic perforators, and the recurrent artery of Heubner. Traditional 2D classification systems often fail to account for the 3D anatomical obstacles that dictate surgical access. This study proposes a morphometric visual framework to guide the selection between pterional and interhemispheric approaches.
Methods:
This study was conducted on 21 patients with posteriorly directed Acom A aneurysms. Morphometric parameters were assessed via 3D-DSA or 3D CTA, focusing on aneurysmal Projections, Inter-A2 ratio (IA2R), A2s coronal Plane and aneurysm Height. Aneurysms are classified as purely posterior aneurysm and posterosuperior aneurysm based on their relation to the coronal A2 plane. Postoperative 3D DSA was done to confirm the result.
Results:
Pterional approach was selected in 15 cases standardly in pure posteriorly directed aneurysms; or when A2 segments are at different coronal planes; or if the IA2R is large in posterosuperior cases. Interhemispheric approach was selected in 6 patients standardly in cases of high-riding aneurysms; or in cases of small IA2R; or when A2 segments were aligned in the same coronal plane. Complete occlusion was achieved in 18 patients with perfect circumferential visualization of the aneurysmal body and clip tips. Three patients exhibited small dog-ear residuals, which remained stable with follow up DSA.
Conclusions:
Although Pterional approach is our standard approach for most cases of posteriorly directed Acom aneurysm because it allows placement of the clip parallel to Acom A. But still the interhemispheric route has to be considered for better visualization in cases where there is a small inter-A2 ratio, or if both A2 segments lying within the same coronal plane, and in high-riding aneurysms.
