A sigmoid and rectum resection with colorectal anastomosis will be performed according to the surgeons standard practice with the addition of intraoperative imaging using fluorescence angiography with indocianyne green to assess colon and rectal tissue perfusion.

A sigmoid and rectum resection with colorectal anastomosis will be performed according to the surgeons standard practice.

The fluorescence angiography was performed after mobilization of the bowel, transection of the rectum, division of the rectal and colon mesentery and central vessels, before specimen extraction or resection and creation of the anastomosis. This site was selected by the surgeon using his or her best judgment and typical standard of care assessment. After this selection, the anesthesiologist administered a bolus of 1 to 2 ml indocianyne green intravenously. Perfusion of the colon was visualized and assessed via fluorescence angiography and the line of demarcation between perfused and nonperfused tissue was noted and compared with the initial planned transection point.