Dear Saif,

many authors have reported the choice of the approach side in relation to the follwing factors: surgeons mostly utilize the pterional approach for anterior communicating artery (AComA) aneurysm surgery. Many factors such as the size and direction of the aneurysm, the non-dominant hemisphere, the aneurysm location in AComA, accompanying aneurysms, the handedness of the surgeon, etc. are considered in selecting either the right or the left pterional approach (Diraz A, et al. Neurol Res 15:273-280,1993, Jose M, et al. Nerol Res 24:291-295,2002, Winn R). A retrospective study of 91 patients revealed that In antero-inferior projecting aneurysms, when approached from the side of A1 dominancy, safe and easy clipping was performed in 45/46 cases. In superior projecting aneurysms, approaches from the side of the ipsilateral proximal A2 posterior to the contralateral A2 yielded favorable results in all (25/25) cases, although the side was A1 non-dominant side. In some cases with posterior projecting aneurysms, approaches from the side of the posteriorly located A2 segment were inappropriate (Kim HJ, et al. J Korean Neurosurg Soc 36:464-469,2004). The authors conclude that in AComA aneurysmal surgery, the A1 dominant side for antero-inferior projecting aneurysms and the side of the ipsilateral proximal A2 posterior to the contralateral A2 for superior projecting aneurysms should be considered prior to other factors. In posterior projecting aneurysms, angiographic

analysis for the side where operator can observe the aneurysmal neck directly is required.