Brief Summary: Evaluation of robot Da Vinci Xi by determining its learning curve.The operating time will be defined by patient then the operating average will be calculated.

Detailed Description: Since the emergence of minimally invasive technology twenty years ago, as a surgical concept and surgical technique for colorectal cancer surgery, its obvious advantages have been recognized. Laparoscopic technology, as one of the most important technology platform, has got a lot of evidence-based support for the oncological safety and effectiveness in colorectal cancer surgery Laparoscopic technique has advantages in terms of identification of anatomic plane and autonomic nerve, protection of pelvic structure, and fine dissection of vessels. But because of the limitation of laparoscopic technology there are still some deficiencies and shortcomings, including lack of touch and lack of stereo vision problems, in addition to the low rectal cancer, especially male, obese, narrow pelvis, larger tumors, it is difficult to get better view and manipulating triangle in laparoscopy. However, the emergence of a series of new minimally invasive technology platform is to make up for the defects and deficiencies. The robotic surgical system possesses advantages, such as stereo vision, higher magnification, manipulator wrist with high freedom degree, filtering of tremor and higher stability, but still has disadvantages, such as lack of haptic feedback, longer operation time, high operation cost and expensive price. 3D system of laparoscopic surgery has similar visual experience and feelings as robotic surgery in the 3D view, the same operating skills as 2D laparoscopy and a short learning curve. Transanal total mesorectal excision (taTME) by changing the traditional laparoscopic pelvic surgery approach, may have certain advantages for male cases with narrow pelvic and patients with large tumor. No prospective study has compared these four surgical techniques. Furthermore, the learning curve still remains a crucial problem in term of data interpretation. We will collect synchronized videos and data on surgeon performance during colorectal surgeries using the Vinci Logger (dVLogger, Intuitive Surgical, Inc.), it is a personalized recording tool that captures synchronized video in the form of endoscope view at 30 frames per second. Kinematic data included characteristics of movement such as instrument travel time, path length and velocity. Events included frequency of master controller clutch use, camera movements, third arm swap and energy use. We will explore and validate objective surgeon performance metrics using novel recorder ("dVLogger") to directly capture surgeon manipulations on the daVinci Surgical System.