Effect of Indocyanine Green Fluorescence Angiography on Anastomotic Leak After Elective Laparoscopic Colorectal Resection: A Prospective Randomized Controlled Trial

Adequate perfusion is essential for colorectal anastomotic healing. Standard intraoperative assessment relies on bowel color, mesenteric pulsation, and bleeding from the cut edge. ICG fluorescence angiography provides real-time near-infrared visualization of bowel perfusion and may identify inadequately perfused segments before anastomosis.

Eligible participants undergoing elective laparoscopic colorectal resection with planned primary anastomosis were randomized using closed-envelope allocation. In the experimental arm, fluorescence was evaluated using a standardized ordinal score: 0, no fluorescence within 60 seconds; 1, delayed or patchy fluorescence at 60 seconds; 2, reduced but homogeneous fluorescence within 30-60 seconds; and 3, rapid homogeneous fluorescence within 30 seconds. Time to fluorescence was recorded at a defined region of interest, and transection was performed at an area showing grade 3 perfusion. In the comparator arm, transection and anastomosis proceeded using standard visual assessment without ICG.

Postoperative evaluation included clinical surveillance. Contrast-enhanced computed tomography of the abdomen and pelvis was obtained when clinically indicated. Clinically significant anastomotic leakage was defined as grade B or C leakage within 90 days and confirmed by clinical findings, contrast imaging, or reoperation.