ICG fluorescence imaging for quantitative evaluation of colonic perfusion in laparoscopic colorectal surgery

Fluorescence technology with indocyanine green (ICG) provides a real-time assessment of intestinal perfusion. However, a subjective evaluation of fluorescence intensity based on the surgeon's visual judgement is a major limitation. This study evaluated the quantitative assessment of ICG fluorescence imaging in determining the transection line of the proximal colon during laparoscopic colorectal surgery. This is a retrospective analysis of a prospectively maintained database of 112 patients who underwent laparoscopic surgery for left-sided colorectal cancers. After distal transection of the bowel, the specimen was extracted extracorporeally and then the proximal colon was divided within the well-perfused area based on the ICG fluorescence imaging. We evaluated whether quantitative assessment of intestinal perfusion by measuring ICG intensity could predict postoperative outcomes: F (max), T (max), T (1/2,) and Slope were calculated. Anastomotic leakage (AL) occurred in 5 cases (4.5%). Based on the fluorescence imaging, the surgical team opted for further proximal change of the transection line up to an adequate fluorescent portion in 18 cases (16.1%). Among the 18 patients, AL occurred in 4 patients (4/18: 22.2%), whereas it occurred in only 1 case (1/94: 1.0%) in the good perfusion patients who did not need proximal change of the transection line. The F (max) of the AL group was less than 52.0 in all 5 cases (5/5), whereas that of the non-AL group was in only 8 cases (8/107): with an F (max) cutoff value of 52.0, the sensitivity and specificity for the prediction of AL were 100 and 92.5%, respectively. Regarding postoperative bowel movement recovery, the T (max) of the early flatus group or early defecation group was significantly lower than that of the late flatus group or late defecation group, respectively. ICG fluorescence imaging is useful for assessing anastomotic perfusion in colorectal surgery, which can result in more precise operative decisions tailored for an individual patient.