The circumferential resection margin was clear in @ patients ( @ % ) in the laparoscopic surgery group and in @ patients ( @ % ) in the open surgery group ( risk difference of -@ % -LSB- @ % CI , -@ % to @ % -RSB- ; P = @ ) , the distal margin was clear in @ patients ( @ % ) in the laparoscopic surgery group and in @ patients ( @ % ) in the open surgery group ( risk difference of -@ % -LSB- @ % CI , -@ % to @ % -RSB- ; P = @ ) , and total mesorectal excision was complete in @ patients ( @ % ) in the laparoscopic surgery group and @ patients ( @ % ) in the open surgery group ( risk difference of -@ % -LSB- @ % CI , -@ % to @ % -RSB- ; P = @ ) .