The aim of this study is to evaluate the ability of a ICG-fluorescence guidance complemented with enhanced reality to correctly document intestinal pre-anastomotic perfusion and to validate the accuracy of this technique with metabolic intestinal cells changes.

Accurate intraoperative evaluation of peri-anastomotic gastrointestinal tract perfusion is essential to reduce the risk of anastomotic complications such as leakage or strictures. Anastomotic leakage is the most dreadful complication of colorectal resections.

Intestinal microcirculation and viability is usually estimated from the color of the serosal surface, presence of peristalsis, pulsation and bleeding from the marginal arteries. This is subjective and based on the experience of the surgeon.

Fluorescence videography integrates a near-infrared endoscope able to detect the signal emitted by a fluorescent dye, Indocyanine Green (ICG), which is administered by intravenous injection. Fluorescence intensity is proportional to the amount of fluorescent dye diffused in the tissue and it consequently is a surrogate marker of tissue perfusion.

The hypothesis is that ICG-fluorescence guidance coupled with enhanced reality would allow a precise and rapid localization of the future anastomotic site in terms of optimal perfusion in laparoscopic colorectal resections.

In patients undergoing elective left-sided colonic resection by laparoscopic approach, resection site and anastomosis perfusion will be evaluated by :

• the visual appreciation of the surgeon
• the fluorescence-based enhanced reality, after injection of ICG and digital process.

A series of peri-operative samplings will also be carried out. In any case, the resection will be performed according to the surgeon's appreciation.

Inclusion Criteria:

• Patient, male or female, from 18 years old
• Patient with sigmoid diverticulosis or diverticulitis
• Patient with colon malignancy
• Patient with rectum malignancy
• Patient with no contraindication to anesthesia and to colonic resection surgery
• Patient able to understand the study and to provide informed consent
• Patient affiliated to the French social security system

Exclusion Criteria:

• Patient undergoing emergency surgery
• Patient undergoing abdomino-perineal resection
• Patient undergoing colonic resection without anastomosis (Hartmann's colostomy)
• Patient with proven or unclear allergic reactions
• Pregnancy or breast-feeding
• Patient in exclusion period (determined by a previous study or in progress)
• Patient in custody
• Patient under guardianship