Efficacy and safety of the treatment modalities from 1997 to 2003.

Fisher-exact tests and Chi-Square tests examine the 0-Hypothesis H0 that there is no difference regarding the rates of symptomatic ischemic stroke, occlusion rate, rebleeding, direct mortality and reinterventions between the two treatment modalities (endovascular group versus microsurgical group).

费希尔精确检验（Fisher-exact tests）与卡方检验（Chi-Square tests）旨在检验零假设H0：两种治疗方式（血管内治疗组与显微外科治疗组）在症状性缺血性脑卒中发生率、闭塞率、再出血率、直接死亡率及再次干预率方面均无差异。