Use of Indocyanine Green Fluorescence in the Assessment of Bowel Perfusion in Emergency and Elective Colorectal Surgery: A Retrospective Cohort Study

Background: The use of indocyanine green (ICG) fluorescence is a well-established technique in colorectal surgery for the evaluation of bowel stump perfusion.However, there is still no definitive acceptance, except for intraoperative macroscopic evidence, with reference to the incidence of anastomotic leakage (AL).The objective of this study is to evaluate whether ICG-guided fluorescence angiography reduces AL rates in both elective and emergency colorectal surgery.Methods: This was a single-center retrospective comparative cohort study.From January 2019 to June 2020, adult patients undergoing elective or emergency colorectal surgery (right/left hemicolectomy, rectal resection, or Hartmann reversal) were enrolled (N=79).In the ICG group (N=40), ICG angiography was used to evaluate colonic stump perfusion before and after creating the anastomosis.Results were compared to a historical control group (N=39) operated without ICG guidance.Group comparisons were analyzed using Pearson's chi-square test.Results: A total of 40 patients underwent surgery; 21 (52.50%) had benign pathology, and 19 (47.50%) exhibited malignant neoplasia.Thirteen (32.50%) were emergency surgeries, and 27 (67.50%)were planned elective surgeries.In almost all cases, the postoperative course was regular; in only one (2.5%)case of transanal total mesorectal excision (TaTME), there was an AL.Other complications were not related to the anastomosis, but some validated the excellent perfusion despite episodes of prolonged acute ischemia due to postoperative hemorrhage.Data were finally compared to a control group of 39 patients where the ICG fluorescence was not used.Conclusions: The study demonstrates a positive association between the use of ICG fluorescence as a method for intraoperative assessment of bowel perfusion and its effectiveness even in emergency conditions and in acute postoperative hemorrhage, detecting an incidence of 2.5% (one case out of 40) of AL.In addition, ICG fluorescence led to a change in the surgical strategy during the procedure.It's evident that to validate our results, further randomized studies on a larger data set are required.It would also be beneficial to evaluate the fluorescence between the mucous and serous layers quantitatively to confirm the reduction of AL rate, better evaluation of bowel perfusion, and, especially in emergency surgeries, the potential reduction of further operations.