ICG is a water-soluble tricarbocyanine dye that interacts strongly with high-density lipoproteins and moderately with low-density lipoproteins, resulting in minimal uptake by tissues other than blood after intravenous administration (12). ICG shows minimal side effects when administered in doses below 0.5 mg/kg. In addition, its rapid clearance with a short half-life of 3–5 minutes (13), mainly by biliary excretion (14–16), contributes to its exceptional safety profile without concerns about residual presence. In addition, the process of ICG injection for contrast imaging is short and does not significantly prolong the total operative time (17).
ICG is characterized by its ability to penetrate tissue and absorb light with wavelengths in the near-infrared spectrum of 800–810 nm, allowing real-time visualization of blood perfusion. Therefore, the ICG fluorescence test is particularly valuable in situations where traditional visual or tactile assessments of tissue integrity and blood circulation are difficult. These scenarios include mesenteric ischemia, intestinal anastomosis, and traumatic injuries, where intestinal viability can have a critical impact on surgical planning.
The application of ICG in trauma surgery includes intraoperative localization/identification of anatomical structures, assessment of tissue perfusion, and detection of intestinal or vascular anastomotic leaks (18, 19). Intraoperative localization/identification of anatomical structures includes identification of the cystic duct, ureters (20), nerves, blood vessels, and thoracic duct to avoid inadvertent injury to these structures during surgery (19). Assessment of tissue perfusion helps in confirming the localization of intestinal bleeding (21, 22), in assessing ischemia or inadequate perfusion at anastomotic sites (10, 11), and in determining the need for additional bowel resection or protective stoma to prevent anastomotic leaks due to poor healing (8).
Systematic reviews and meta-analyses have shown that the use of the ICG fluorescence test to determine resection margins and assess anastomotic perfusion effectively reduces the incidence of leakage and related complications such as fistula formation, reoperation, permanent stoma, gastrointestinal dysfunction, wound-related complications, intestinal strictures, reduced quality of life, and mortality (18).
Arezzo et al. (23) reported an effective risk reduction of anastomotic leakage regardless of gender, age, body mass index (BMI), or distance of the tumor from the anal verge by intraoperative assessment of surgical anastomotic blood flow in rectal tumors using ICG imaging. Degett et al. (24) and Campbell et al. (25) published systematic reviews and meta-analyses on the use of ICG in gastrointestinal surgery, including the assessment of blood flow at anastomotic sites in the esophagus and colorectal region. These studies found a reduction in the anastomotic leakage rate from 8.5 to 3.3% and from 20 to 0%, respectively. Despite negative reviews in some studies that reported no significant differences after ICG use (26), it should be noted that the additional surgical time and cost of this technique are minimal.
Fransvea et al (9) conducted a systematic literature review and concluded that 36% of patients with intestinal ischemia who underwent ICG fluorescence examination had their surgical approaches changed. Of these, a more conservative treatment strategy was chosen in 21.6% of cases, resulting in significant clinical benefits in 11% of patients, including a reduction in the length of the resected bowel and a reduction in surgical complications. A comparison between visual inspection and ICG findings revealed a discrepancy in 35% of assessments, which is closely consistent with the above-mentioned 36% of patients in whom surgical approaches were changed.
ICG is also commonly used in trauma patients to assess bowel and solid organ viability and ischemic tissue damage in the head, face, and limbs. In 23.9% of cases, surgical plans were changed as a direct result of ICG fluorescence testing results (9). This included changes in the surgical field and, in some cases, a switch to more conservative treatments, thereby avoiding organ or bowel resection. Taken together, these results underscore the importance of ICG fluorescence testing in guiding surgical decisions.
Our case was complicated by hematomas in the mesentery and serosa obstructing visual observation of the external appearance, peristalsis and palpation, which made it difficult to determine intestinal viability. Therefore, we used ICG fluorescence test to determine intestinal viability from the mesocolonic hematoma, and the visible fluorescence in the mesentery and mesocolon under ICG optics indicated excellent blood supply to the descending colon (Fig. 3). This led to the revision of our final surgical plan and the avoidance of intestinal resection.
A case with similar features to ours was previously presented at the Canadian Surgery Forum 2016 (27). It was a 45-year-old woman who was involved in a motor vehicle accident and suffered blunt abdominal trauma resulting in intra-abdominal bleeding and a small bowel mesenteric hematoma. Due to the considerable size of the hematoma, the patient underwent intraoperative ICG angiography, which revealed small bowel ischemia, requiring small bowel resection.
According to the American College of Radiology (ACR) guidelines (28), CT angiography (CTA) is the preferred diagnostic tool when acute bowel ischemia is suspected. CTA is preferred due to its speed, accuracy, and noninvasive nature. Furthermore, compared with other imaging modalities such as digital subtraction angiography, ultrasound (US), and magnetic resonance angiography, it is highly accurate in assessing the degree of arterial stenosis, with sensitivity and specificity rates reported as high as 93–100%. Therefore, “CTA of the abdomen and pelvis with intravenous contrast” is considered “usually adequate” when acute mesenteric ischemia is suspected.
Our team’s literature search did not reveal any comparative studies on the diagnostic accuracy of intraoperative ICG with preoperative CT. Given the small number of case reports on intraoperative ICG, it is likely that comparative diagnostic studies are also lacking.
Among the numerous published cases on the intraoperative use of the ICG fluorescence test, we believe our case is the first to use ICG to assess the possibility of colon ischemia due to a mesenteric colon hematoma and demonstrate successful conservative treatment. The ICG fluorescence test does not change the general need and indication for damage control surgery in the acute care setting, especially given the current gap in large controlled trials for more robust evidence (9). However, the success of our case highlights the utility of assessing intestinal perfusion during diagnostic laparoscopy for blunt abdominal injuries with potentially compromised colon mesenteric blood supply.
