*3.3.1 Intraoperative fluorescence angiography in colorectal surgery used for the evaluation of the anastomosis*

Anastomotic leakage remains among the most feared and challenging complications after colorectal resection. The etiology of leaks includes patient factors, technical factors, and anastomotic perfusion. The known etiology of leaks includes the following: different patient factors, technical factors, and anastomotic blood supply. An intact anastomotic irrigation pattern is particularly vital in the process of anastomotic healing. The air leak testing and intraoperative colonoscopy are

#### **Figure 5.**

*The surgeon uses a portable fluorescence imaging device during breast removal. Photo source: www. shutterstock.com.*

methods that can be done to establish the anastomotic integrity intraoperatively. Among the major causes of anastomotic leakage is impaired vascularization and a minimal deficit in blood supply, both aspects being difficult to detect under white light. Fluorescence angiography with indocyanine green (ICG-FA) is employed in colorectal surgery in order to evaluate the blood supply in the area of an anastomosis. Studies with ICG-FA in open and laparoscopic interventions indicated a lower rate of anastomotic leakage; for example, the PILLAR II study reported a leakage rate of 1.4%. There were researches in this field, such as is the case of Carus and Pick [15] that reported impressive results in clinical outcome and patient prognosis. Likewise, the use of ICG-FA in the group of patients studied potentially led to a reduction of the leakage rate by 48%. Another systematic review from Blanco-Colino and Espin-Basany [16] looks at 1302 patients from five nonrandomized studies in which fluorescence imaging significantly decreased the anastomotic leak in cases operated on for colorectal cancer. Lower leak rates were found in rectal cancer surgery, as well (ICG 1.1% vs. non-ICG 6.1%; p = 0.02) (**Figure 6**).
