The primary goal of any surgery is to achieve optimal surgical results. To meet this objective, the visualization and display of significant and critical structures are of crucial importance to the surgical workflow. The rapid development of technology has led to greater insights in the field of minimally invasive surgery (MIS) and, ultimately, to a potentially better outcome for the patient.
As in adults, laparoscopic cholecystectomy (LC) has now become the technique of choice also in the pediatric population . However, despite the improvement in the learning curves of pediatric surgeons, the procedure is not without complications . The most serious complications include biliary tree injuries, usually resulting from poor visualization/misinterpretation of anatomic structures [6,7,8].
As recently published [17,18,19,20], the incorporation of ICG fluorescent cholangiography (FC) into LC has the potential to provide real-time visualization of the extrahepatic biliary tree prior to commencing dissection within the Calot’s triangle. The evolving technologies have recently provided the surgeons perfect camera systems to achieve even better intra-operative visualization.
The new IMAGE1 S™ RUBINA™ components provide surgeons a series of advantages compared with the existing IMAGE1 S™ camera platform. These options include native 4 K resolution, offering very good image quality in both white light and ICG-NIRF modes, and natural color rendition; possibility to adopt 3D technology in 4 K and enhanced 3D quality image compared to previous model; automatic horizon control; laser-free LED light source for white light, and ICG-NIRF providing excitation of ICG and autofluorescence in the near-infrared range, durability and constant light intensity, and control via touch display and footswitch. The OPAL1® ICG-NIRF technology integrated into the RUBINA™ camera platform provides the overlay mode with ICG-NIRF data displayed in green or blue onto the standard white light image or intensity map mode for displaying signal intensity in the overlay image or monochromatic mode for ICG-NIRF signal alone (Fig. 1). In our experience, we preferentially adopted the overlay mode, as the ICG-NIRF data overlapped onto the standard white light image allowed us to keep a constant assessment of anatomy and continuously identify the position of critical biliary structures, while performing the operation without the need to switch between the ICG-NIRF and the standard bright light view.
Use of ICG-FC was very helpful to easily detect the cystic duct (CD), the common hepatic duct (CHD), the CD–CHD junction, the common bile duct (CBD), the right hepatic duct, and accessory hepatic ducts and did not require any additional ports or instrumentation (Figs. 2 and 3). Improved anatomical identification allowed for targeted dissection of the CD and aided to confirm cystic artery versus CD during dissection. We found the use of ICG-FC very useful to orient the surgeon to the location of biliary structures, particularly in the setting of excess adipose tissue overlying the Calot’s triangle, or adhesions resulting from inflammatory processes, or in case of aberrant anatomy.
When performing cholecystectomy, the surgeon must remember that there are many variations from the normal anatomy of the vessels and bile ducts in the Calot’s triangle. Thanks to the use of ICG-FC, we were able to identify anatomy variants in 33.3% of our cases, including Moynihan’s or caterpillar hump of the right hepatic artery, supravescicular bile duct, and short cystic duct.
Numerous variations in origin and branching pattern of right hepatic artery have been reported. In some cases, tortuous right hepatic artery producing sinuosity may come very close to the gallbladder and cystic duct in the form of “caterpillar hump or Moynihan’s hump’’ . If such a hump is present, the cystic artery in turn is very short (Fig. 5). In this situation right hepatic artery is either liable to be mistakenly identified as cystic artery or torn in attempts to ligate the cystic artery . Injury to right hepatic artery leads to ischemic necrosis of right functional lobe of the liver. So, the presence of caterpillar hump should be suspected when an unusually large cystic artery is viewed through the laparoscope .
Another debated point is the optimal dosage and timing of administration of ICG to obtain optimal visualization of the extrahepatic biliary tree [24, 25]. We adopted a dosage of 0.35 mg/kg in all cases, and the median time of administration was 15.6 h prior to surgery. Strong fluorescence of the background tissues was visualized intraoperatively in one patient, in whom the ICG administration was performed just 8 h prior to the procedure (Fig. 4). Based upon our experience, we believe that ICG administration should be performed the day before surgery, average 16–18 h prior to the procedure, to obtain better fluorescence contrast between the bile duct and background tissues, thereby enhancing the efficacy of ICG-FC during LC.
It is also important to consider that some drugs can interfere with the ICG mechanism of action. In our series, we reported a technical failure in intra-operative visualization of ICG-NIRF in one patient affected by Crigler–Najjar syndrome type 2, who was in treatment with phenobarbital. In such patient, we observed a weak fluorescence of biliary structures, which did not improve following intra-operative administration of additional ICG solution.
This study has further confirmed that ICG-FC during LC has the potential to increase both patient safety and procedural efficiency via enhancement and optimization of tissue visualization. No post-operative complications occurred in our series. However, conversion from laparoscopic to open cholecystectomy is sometimes mandatory, due to inability to identify anatomy, need to avoid injury, or insurance of patient safety. Furthermore, this technology is very easy to use as ICG-NIRF view can be directly activated by pushing a button on the camera without increased need for staffing or additional supplies in the operative theater, beyond the addition of a NIR-capable laparoscopic equipment.
Regarding the costs to adopt this innovative imaging technology, you need to buy the IMAGE1 S ™ RUBINA™ system, including the specific camera head and the light source, and a separate high-resolution scope, TIPCAM®1 RUBINA™, with two distally integrated video chips for ICG-NIRF imaging, manufactured by KARL STORZ SE & CO. KG, Tuttlingen, Germany. The cost of the IMAGE1 S™ RUBINA™ system is about 50.000 Eur, whereas the cost of the scope, TIPCAM®1 RUBINA™, is about 5.000 Eur. The ICG dye costs about 40 Eur per vial. So, considering that this technology is easy to use, safe, and versatile, if the operating room is provided with all the equipment needed for ICG-NIRF, it may be adopted in every routine pediatric LC with practically no adjunctive costs except for the ICG vial.
No absolute contraindications exist for the administration of ICG dye, and ICG has been used safely in patients with documented iodine allergy [26, 27]. Risk of an adverse event with ICG is small. Anaphylactic reaction has been reported at a rate of 0.003%, with a 0.34% overall incidence of mild adverse reactions [26, 27]. We adhere to the general recommendation that ICG not to be used for patients with a shellfish allergy or iodine contrast sensitivity, and we did not experience any adverse reactions with the use of ICG.
Our preliminary experience suggested that the new RUBINA™ technology was very effective to perform ICG-FC during LC in pediatric patients. The advantages of this technology include the possibility to overlay the ICG-NIRF data onto the standard white light image and provide surgeons a constant fluorescence imaging of the target anatomy to assess position of critical biliary structures or presence of anatomical anomalies and safely perform the operation.