Clinical effect and standardization of indocyanine green angiography in the laparoscopic colorectal surgery

The Miraculous Diagnostic Role of Indocyanine Green in a Diabetic Foot Ulcer: A Rare Case Report

Diabetes is a chronic metabolic disorder characterized by elevated levels of glucose in the blood. This causes small nerve polyneuropathy resulting in diabetic foot ulcers. A diabetic foot ulcer is an open sore or wound that develops as a result of chronic diabetes. Indocyanine green angiography (ICGA) near-infrared (NIR) can provide real-time visualization of blood flow within the microvasculature of the underlying organ. Here, we discuss a 63-year-old patient who came with a diabetic foot ulcer over his right great toe. His blood glucose level was 208 mg/dl. He drinks alcohol occasionally and smokes regularly. The tissue perfusion of his right foot was checked using the indocyanine green dye, after which orthopedic surgeons were consulted, and the gangrenous part was amputated.

Risk factors for ischemia/necrosis of the colonic stump after proctectomy and delayed coloanal anastomosis

INTRODUCTION

Delayed coloanal anastomosis (DCAA) is a two-stage procedure. DCAA has been increasingly reused in recent years in the management of rectal cancer. Such increased use of DCAA has highlighted the complications associated with this procedure. We aimed to evaluate the risk and risk factors of ischemia/necrosis of the colonic stump between the two stages of DCAA.

PATIENTS AND METHODS

All patients who underwent a proctectomy with a DCAA were included in this retrospective single-centre study from November 2012 to June 2022. Two groups of patients were defined: patients with a well vascularized colonic stump (well vascularized group) and those who experienced ischemia or necrosis of the colonic stump (ischemic group). The primary endpoint was the rate of ischemia or necrosis of the colonic stump and an evaluation of the associated risk factors.

RESULTS

During the study period, 43 patients underwent DCAA. Amongst them, 32 (75%) had a well-vascularized colonic stump (well-vascularized group) and 11 (25%) ischemia of the colonic stump (ischemic group). Relative to patients in the well-vascularized group, those in the ischemic group were more often men (81.8% vs 40.6%, p = 0.034), had a higher BMI (29.2 kg/m2 vs 25.7 kg/m2, p = 0.03), were more frequently diabetic (63.6% vs 21.9%, p = 0.01) and more frequently had had preoperative radiotherapy (100% vs 53.1%, p = 0.008). On the preoperative CT scan, the interspinous diameter was shorter in the ischemic group (9.4 ± 1.01 cm vs 10.6 ± 1.01 cm, p = 0.001), the intertuberosity diameter was shorter (9.2 ± 1.18 cm vs 11.9 ± 1.18 cm, p < 0.0001), and the length of the anal canal was longer (31.9 ± 3 mm vs 27.4 ± 3.2 mm, p < 0.0001).

CONCLUSION

This study highlights clear risk factors for ischemia/necrosis of the colonic stump after proctectomy with DCAA.

Lymphatic flow mapping during colon cancer surgery using indocyanine green fluorescence imaging

With the development of surgical technology, indocyanine green (ICG) fluorescence navigation systems may be useful in various areas of colorectal surgery, including tumor location confirmation, bowel perfusion, ureter identification, and lymph node mapping. This review provides an overview of the current status of ICG-based navigation surgery in colorectal surgery, emphasizing its role in lymphatic flow mapping. This state-of-the-art approach will allow for appropriate oncological surgeries in the field of colorectal cancer and improve the patient's prognosis.

The Safe Values of Quantitative Perfusion Parameters of ICG Angiography Based on Tissue Oxygenation of Hyperspectral Imaging for Laparoscopic Colorectal Surgery: A Prospective Observational Study

BACKGROUND

Safe values for quantitative perfusion parameters of indocyanine green (ICG) angiography have not been fully defined, and interpretation remains at the surgeon's discretion. This prospective observational study aimed to establish the safe values for the quantitative perfusion parameters by comparing tissue oxygenation levels from HSI images in laparoscopic colorectal surgery.

METHODS

ICG angiography was performed using a laparoscopic near-infrared (NIR) camera system with ICG diluted in 10 mL of distilled water. For quantitative perfusion parameters, the changes in fluorescence intensity with perfusion times were analyzed to plot a time-fluorescence intensity graph. To assess real-time tissue oxygen saturation (StO2) in the colon, the TIVITA® Tissue System was utilized for hyperspectral imaging (HSI) acquisition. The StO2 levels were compared with the quantitative perfusion parameters derived from ICG angiography at corresponding points to define the safe range of ICG parameters reflecting good tissue oxygenation.

RESULTS

In the regression analysis, T1/2MAX, TMAX, slope, and NIR perfusion index were correlated with tissue oxygen saturation. Using this regression model, the cutoff values of quantitative perfusion parameters were calculated as T1/2MAX ≤ 10 s, TMAX ≤ 30 s, slope ≥ 5, and NIR perfusion index ≥50, which best reflected colon StO2 higher than 60%. Diagnostic values were analyzed to predict colon StO2 of 60% or more, and the ICG perfusion parameters T1/2MAX, TMAX, and perfusion TR showed high sensitivity values of 97% or more, indicating their ability to correctly identify cases with acceptable StO2.

CONCLUSION

The safe values for quantitative perfusion parameters derived from ICG angiography were T1/2MAX ≤ 10 s and TMAX ≤ 30 s, which were associated with colon tissue oxygenation levels higher than 60% in the laparoscopic colorectal surgery.

Ileal long-segment ischemia after the unintended ligation of variant ileal branch during laparoscopic right hemicolectomy

The variant terminal trunk of the superior mesenteric artery (SMA) could be confused with the ileocolic artery (ICA) as it runs on the right side of the superior mesenteric vein. If the variant ileal branch of SMA is mistaken for the ICA, unintentional ligation could cause long-segment ischemia in the ileum. We encountered a rare case of ileal ischemia caused by unintentional ligation of the variant ileal branch of the SMA during laparoscopic right hemicolectomy, which was confirmed by indocyanine green (ICG) angiography and hyperspectral imaging (HSI). Intraoperative real-time perfusion monitoring using ICG angiography and tissue oxygen saturation monitoring using HSI could help detect segments of hypoperfusion and prevent hypoperfusion-related anastomotic complications.