Quantitative assessment of intraoperative perfusion using fluorescence imaging for the prevention of anastomotic leakage in colorectal surgery: first experience

AIM: to evaluate discrepancies between subjective intraoperative perfusion assessment and qualitative and quantitative ICG fluorescence angiography, as well as the impact of quantitative perfusion assessment on intraoperative surgical decision-making during colorectal resections.

PATIENTS AND METHODS: this prospective single-center study included patients aged 18 years and older with histologically confirmed adenocarcinoma of the distal sigmoid colon, rectosigmoid junction, or rectum, who underwent surgery with primary colorectal anastomosis between May and November 2025. No restrictions regarding tumor stage were applied. Intraoperatively, fluorescence angiography with ICG (0.1 mg/kg) was performed. Perfusion was assessed using the UFF-630/675-01-BIOSPEC system with quantitative analysis of fluorescence parameters, including maximum intensity (Imax), time to peak intensity (Tmax), inflow rate, and outflow rate. The primary outcome was the frequency of discrepancies between visual, qualitative, and quantitative perfusion assessment of the colonic wall. Postoperative complications were recorded within 30 days and classified according to the Clavien-Dindo classification, while anastomotic leakage was graded according to the ISREC classification.

RESULTS: a total of 20 patients were included in the study. Impaired colonic wall perfusion was identified in 3/20 (15%) patients based on visual assessment, in 3/20 (15%) patients based on qualitative ICG assessment, whereas quantitative analysis revealed signs of reduced perfusion in 6/20 (30%) patients. Subjective perfusion assessment was based on visual signs of blood supply. The presence of bright red bleeding and a visibly pulsatile blood jet were evaluated. The presence of bright red blood alone was considered a doubtful finding, whereas a pulsatile jet of bright red blood was interpreted as a positive result. In the absence of these signs, additional bowel resection was performed prior to ICG assessment. Thus, a discrepancy between subjective visual and quantitative perfusion assessment was observed in 3/20 (15%) patients, and a similar discrepancy between qualitative ICG assessment and quantitative analysis was also observed in 3/20 (15%) patients. Anastomotic leakage occurred in 2/20 (10%) patients, including 1/20 (5%) case of grade A and 1/20 (5%) case of grade B according to the ISREC classification. In both patients, a decrease in Imax to 83% and 87%, respectively, was observed. In one of these patients, visual perfusion assessment was considered adequate, whereas qualitative ICG assessment was classified as weakly positive in both cases. Negative visual and qualitative perfusion assessments were consistent with quantitative findings in 2/20 (10%) patients.

CONCLUSION: the preliminary data demonstrate the presence of discrepancies between subjective, qualitative, and quantitative assessment of intestinal wall perfusion. The clinical significance of these findings should be further evaluated in larger prospective studies.

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