الفهرس 
BASIC PRINCIPLES OF FLUORESCENCE GUIDED SURGERYOnly 14 pages are availabe for public view
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Abstract
I
ndocyanine greenis a water-soluble tricarbocyanine dye developed by Kodak Research Laboratories for near-infrared (NIR) photography in 1955. It was first approved by the Food and Drug Administration (FDA) in 1956 to study hepatic and cardiac functions in human. ICG is excited when illuminated by NIR light with wavelength of 778 – 806 nm. The fuorescence emission is maximal at wavelength of 832 nm and can penetrate tissue up to 15 mm. This emitted light is then captured with special camera to be transformed and displayed as visible light. ICG is injected intravenously and due to its protein-binding characteristic, majority of the plasma protein-bound ICG stays within the intravascular space. It is then almost exclusively metabolized by the liver and excreted into bile at a rate of 18 – 24% per minute. The half-life is shortest at around 3 – 4 min during the first 10 – 20 min after injection. Although the clearance rate decreases subsequently, it is cleared quickly enough to allow multiple injections in most procedures. The use of ICG is relatively safe: comparing to lethal dose up to 80 mg/kg, the standard dose of 2 mg/kg is basically nontoxic, with the exception of iodide allergy which is uncommon.
Indocyanine green is safe and has many potential applications. It has demonstrated its usefulness in visualizing anatomy of biliary system, vascular territory in various organs, tissue perfusion and tumor. More research is needed to determine the true extent of ICG application in pediatric patients. Whether it is a complementary to or replacement of traditional methods is to be determined, but certainly this is a contrast agent with huge potential.
Laparoscopic cholecystectomy is the treatment of choice for symptomatic gallstones and biliary dyskinesia, among other indications in children. The techniques and instruments used in children are similar to those used in adults, but more difficulty may be encountered in children with gallbladder disease, as anatomical variations are more common and the abdominal space is more limited due to the relatively larger livers. Thus, more care must be taken during dissection, especially around the Calot’s triangle. ICG can be a valuable tool in identifying the cystic duct and common bile duct (CBD) before the dissection of Calot’s triangle, allowing for a more careful dissection with minimal risk of injury to either the biliary tree or blood vessels. Experience of laparoscopic cholecystectomy with ICG in adult showed a faster and more accurate visualization of the cystic duct and CBD, which helped to avoid unintentional bile duct injury. This is particularly useful when the anatomy is difficult to identify, which may be the result of variation in biliary anatomy or history of severe inflammation, leading to injury of Calot’s triangle and fibro tic gallbladder.
Intra-operative cholangiogram (IOC) is the gold standard for diagnosis of biliary atresia and is usually performed together with Kasai operation. Conventionally, it involves the injection of radio-opaque contrast material into the gallbladder and observes the drainage of contrast in the biliary system. Hirayama et al. first reported their experience to use ICG as an alternative in 2015. ICG was injected on the day before the operation, and was observed with NIR camera during the operation. They were able to demonstrate the absence of fluorescence in the biliary tract and confirmed the diagnosis of biliary atresia during the operation. The use of ICG cholangiogram can better visualize the biliary flow of the hepatic duct at the portahepatis before dissecting the fibrous cone, thus a more appropriate level and extent of dissection can be determined. Moreover, it can also be used to evaluate biliary excretion post-operatively by observing the fuorescence of the feces and compare it to the pre-operative value.
Choledochal cyst treatment can be complicated due to the modified anatomy caused by biliary dilation and acute pancreatitis. ICG dye facilitated the identification of the cystic duct in Calot’s triangle by delimiting the dilation of the common bile duct from the hepatic artery and the portal vein. Also, defining the anatomy of the dilated common bile duct in its union with the duodenum facilitated a safe dissection and ligation of the cyst to the intestine, avoiding injury to it.
This study aimed to evaluate the true extent of Indocyanine green application in pediatric patients Whether it is a complementary to or replacement of traditional methods and its usefulness in visualizing anatomy of biliary system, vascular territory in various organs, tissue perfusion and tumor localizationas regarding intra-operative time, postoperative hospital stay and complications at Ain Shams University, Pediatric surgery department.
This was a descriptive study that was conducted on children with hepatobiliary diseases who were admitted in the pediatric surgery department of Ain Shams University hospitals. All patients were operated by indocyanine green enhanced fluorescence guided surgery.
The results of our present study can be summarized as follows:
In our study, the mean ± SD ICG dosage (cm) in LC group were; 3.75 ± 0.46, the mean ± SD ICG dosage (cm) in Biliary atresia group was 1.50 ± 0.00, while the mean ± SD ICG dosage (cm) in Choledochal Cyst group was 3.00 ± 1.41
In our study , the mean ± SD time of injection (hour Pre-Operative) in LC group was; 11.13 ± 0.83, mean ± SD time of injection (hour Pre Operative) in Biliary atresia group was 12.00 ± 0.00, while the mean ± SD time of injection (hour Pre Operative) in Choledochal Cysts group was 11.00 ± 1.41.
Regarding the LC group in our study, we noticed adequate visualization of CBD with usage of ICG florescence in 75% of our population with evident cystic duct and common hepatic duct in all patients.
Successful Kasai procedure results in significant DROP of bilirubin level and liver profile, in our BA group, there was statistically significant difference between pre- and post-operative tests
In the CC group in our study, we had a satisfactory visualization of the dilated common bile duct with ICG florescence was noted in 100% of our population with evident cystic duct and common hepatic duct.
In the group of laparscopic cholycystectomy , the Operative time ranged from 25 to 90 minutes . The hospital stay ranged from 1 to 2 days with no reported complications .
In the group of biliary atresia , the mean operative time was 180 minutes. The hospital stay ranged from 5 to 7 days with no reported blood loss or bile leakage.
In the group of choledochal cyst , the mean operative time was 165.00 ± 21.21 minutes. The hospital stay ranged from 6 to 8 days with no reported vascular injury or biliary spillage .