Objective To evaluate the safety and efficacy of stent placement for the treatment of complex intracranial aneurysms.Data sources We searched six databases,including Pubmed,Embase,SCI-expanded,the Cochrane Library,ISI Proceedings and ProQuest Dissertations & Theses for the relevant studies using multiple key words from December,1997 to February,2009.Study selection Thirty-three studies about stent placement for intracranial aneurysms were identified,which reported data from a total of 1069 patients with 1121 intracranial aneurysms.Data extraction We prepared a standardized data extraction form (DEF),which was used by two independent researchers to extract data from the included 33 studies.Results The overall initial complete occlusion rate was 52.5％ (456/869,95％ CI:49.2％-55.8％).The overall complication rate was 14.3％ (162/1130,95％ CI:12.3％-16.4％),of which 3.6％ (38/1044,95％ CI:2.5％-4.8％) were permanent.Clinical follow-up showed a dependence rate of 8.4％ (39/465,95％ CI:5.9％-10.9％).Angiographic follow-up showed an improvement rate of 24.3％ (117/481,95％ CI:20,5％-28.2％) and a recurrence rate of 12.9％ (62/481,95％ CI:9.9％-15.9％).Chi-squared tests were performed to compare the following subgroups:self-expandable vs.balloon-expandable stents,unruptured vs.acutely ruptured aneurysms,and with vs.without pre-medication.Statistical significance was reached in eight tests.Conclusions Intracranial stent is a safe and effective tool for embolizing complex intracranial aneurysms.Self-expandable stents are significantly easier and safer than balloon-expandable stents with respect to navigation and deployment through the tortuous cerebral vasculature.Patients with acutely ruptured aneurysms are more likely to be deoendent,but not more likely to suffer more procedure-related complications.