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Indocyanine Green (ICG) is a fluorophore commonly used in minimally invasive surgery for tissue visualization under near-infrared (NIR) fluorescence imaging. It is highly effective for localizing the ureter during complex surgeries. Here's how you can use it:
Preparation
ICG Preparation:
Dissolve ICG in sterile water or saline (recommended concentration: 2.5 mg/mL).
Ensure the ICG solution is fresh to maintain its fluorescence properties.
Equipment Setup:
Use laparoscopic or robotic equipment equipped with NIR fluorescence imaging capability (e.g., Firefly in da Vinci systems or other fluorescence imaging scopes).
Patient Preparation:
Insert a ureteral catheter if necessary, which can help in targeted delivery of ICG.
Confirm absence of allergy to iodine or ICG in the patient.
Procedure
1. Intravenous Administration
Administer ICG intravenously (dose: 0.25–0.5 mg/kg) approximately 5–10 minutes before imaging.
Wait for the ICG to circulate and selectively highlight the ureters due to its excretion by the kidneys.
2. Direct Ureteral Instillation (Optional)
If more precise localization is needed, instill a diluted ICG solution directly into the ureter through a catheter. This method allows specific highlighting of the ureter.
3. Imaging and Localization
Switch to the NIR mode on your laparoscopic or robotic system.
Observe the ureter fluorescing green, which stands out clearly against non-fluorescent surrounding tissues.
Follow the fluorescence to trace the course of the ureter and avoid inadvertent injury during dissection.
Tips for Optimal Results
Timing:
Ensure sufficient time for ICG to reach the ureter post-intravenous injection. This may vary based on renal function.
Avoid Overloading:
Excessive ICG doses can result in background fluorescence, reducing contrast.
Monitor Renal Function:
In cases of renal insufficiency, excretion and fluorescence may be delayed or reduced.
Enhance Visualization:
Use minimal lighting in the NIR mode to enhance contrast.
Complementary Techniques:
Combine ICG imaging with preoperative imaging (CT/MRI) and intraoperative landmarks for precise localization.
Applications
Pelvic Surgery: Localization of ureters in oncologic or endometriotic surgeries.
Ureterolysis: During complicated dissection.
Minimizing Ureteral Injury: Particularly in gynecological and colorectal procedures.
Using ICG for ureter localization is a safe and efficient technique that enhances surgical precision and minimizes complications.
