The randomized study to evaluate whether the instruments for clearing laparoscope reduce the surgical stress in colorectal cancer surgery.

Interventions: Clearing lens of laparoscope using the warm saline and gaze Clearing lens of laparoscope using the instrument for clearing lens of laparoscope (OpClear) Primary outcome(s): To evaluate whether instruments for clearing lens of laparoscope reduce the multifaceted surgical stress in the colorectal operation. Study Design: Parallel Randomized