Objective    To investigate the surgical skills and indications of delayed microsurgical treatment in ruptured intracranial aneurysms of posterior communicating artery (PcoA) by keyhole approach.     Methods    A retrospective analysis was made in 103 cases of ruptured intracranial aneurysms of PcoA who hospitalized in our department from 2006 to 2010. All cases had been diagnosed by distal subtraction angiography (DSA) or computed tomography angiography (CTA). These ruptured aneurysms were all treated with microsurgery in 2 weeks later by superciliary arch keyhole approach for craniotomy.     Results    The ruptured aneurysms were clipped successfully in 103 cases. Postoperative vasospasm was found in 3 cases

and developed into cerebral infarction finally. Two of them were recovered after treatment

but the left one died. Among the 103 cases

good outcome was achieved in 102 cases (99.03%)

and only 1 case (0.97%) was dead. CTA in 1 week postoperatively showed that artery clipper and aneurysm disappeared and supply artery kept well. In the 42 cases receiving CTA or DSA in 3 or 6 months after operation

no reoccurrence was found.     Conclusion    Keyhloe microsurgery is a microinvasive treatment for ruptured aneurysm of PcoA

and can reduce surgical trauma and complications. Selective microsurgical treatment

accurate understanding of anatomic structure and microsurgery technique are key points to successful operation.