Keyhole approach to sub-callosal distal anterior cerebral artery aneurysms: a technical report

Background Among the rare distal anterior cerebral artery (DACA) aneurysms, those lying below the genu of the corpus callosum are considered even rarer. While the conventional interhemispheric approach provides inadequate exposure to these aneurysms, the more popular basal approaches lead to frontal sinus violation with attendant risks. In addition, both these standard approaches are maximally invasive to the skin, bone and brain. Methods Three patients with sub-callosal DACA aneurysms were treated. A2 segment aneurysm was treated using a supra-orbital keyhole craniotomy, while the other two (distal, involving proximal A3 segment) were dealt with using pre-coronal unilateral keyhole parasagittal craniotomy and an anterior interhemispheric approach. The procedures were completed uneventfully. The clinical, radiological features and surgical videos were reviewed. Results The mean age was 47.3 years (37–53 years) with two females and one male. Two patients had acutely ruptured aneurysms, and all were in good clinical grades. One patient had an A2 segment aneurysm close to the anterior communicating artery, while the other two patients had a proximal A3 aneurysm, just beneath the genu of the corpus callosum. The aneurysm was completely occluded in all 3 patients. At follow-up (mean: 16.4 months), all 3 patients are functionally independent. Conclusion Subcallosal DACA aneurysms may be amenable to the keyhole approaches that spare the frontal sinus and the bridging veins. Case selection and experience with the traditional approaches are however, mandatory.