未破裂脳底動脈先端部動脈瘤の直達クリッピング術の戦略  [in Japanese] Surgical Strategy of Direct Neck Clipping for Unruptured Basilar Tip Aneurysm  [in Japanese]

The surgery of direct neck clipping of basilar tip aneurysm is still a challenge among various aneurysm surgeries. In this surgery, the transsylvian approach is preferred to the subtemporal approach. There are several tactics to improve operative results. A wider surgical field can be obtained by dissecting the sylvian fissure from the distal segment. And anterior clinoidectomy and unroofing of the optic canal widen the space around the internal carotid artery and its cisternal cavity. Dividing the posterior communicating artery is crucial to managing the procedure. For low-position aneurysms, posterior clinoidectomy by surgical drill is inevitable to secure the temporary clipping on the basilar artery. The key issue of neck clipping is how to preserve the perforators originating from the basilar tip and P1 segment of posterior cerebral artery. In the first step of clipping, we prefer incomplete dome or neck clipping, which makes detachment of perforators away from the aneurysm much easier. By gently pushing cottonoid or Surgicel underneath the aneurysm, a second clip can be applied for complete neck clipping. With these tactics, the result of direct neck clipping of basilar tip aneurysm is excellent as long as the aneurysm is smaller than 10 mm.