Methods A new type of circular retractor was used to draw and expose anus and rectum in 112 cases during operation,and contrast with the old routine operation in 100 cases with the circular retractor.

• 方法将研制的不锈钢肛肠阴道尿道手术环形牵开器(简称环形牵开器)用于112例肛直肠手术的牵拉显露,并选择常规肛直肠手术100例作为对照。