How I do it: left posterior cerebral artery P1-2 segment dissecting aneurysm distal clipping via an A1-RAG-P2 bypass.

Background: Posterior cerebral artery (PCA) P1-2 segment dissecting aneurysms are difficult because regular craniectomy aneurysm clipping or intravascular interventional therapy is not applicable.

Method: We report distal clipping of a PCA P1-2 segment dissection aneurysm with an anterior cerebral artery (ACA) A1-radial artery graft-PCA P2 bypass.

Conclusion: This case demonstrates the value of an ACA-RAG-PCA bypass in the therapy of a PCA dissecting aneurysm.