In the Intervention group the Coloshield Device (double balloon system) will be introduced at the beginning of surgery followed by a washout of the rectum with 500ml of saline solution. The grade of macroscopic contamination will be assessed.

In the control Group the grade of macroscopic contamination will be assessed after rectal washout with 500ml of saline solution.

Coloshield is designed to occlude the rectum during surgery thus enabling the possibility for rectal washout and maintaining a clear operating field. The rod-shaped Instrument contains two silicon balloons which are inflated by means of a catheter. Several holes at the section in between the two balloons are connected to another catheter, which enable negative pressure to be established. By insufflation of the two balloons and establishment of a negative pressure between the balloons by means of connection to a closed drainage bottle the colon is occluded for the duration of surgery.

The position of the deployed Coloshield at beginning of surgery and after 30 minutes is measured by rigid rectoscopy in cm from anal verge. Any slippage of the device during surgery is documented.