The Use of Fluorescent Imaging for Intraoperative Cholangiogram During Laparoscopic Cholecystectomy

The purpose of this study is to evaluate whether systemically injected ICG, when fluorescing in response to NIR illumination, can assist with the identification of the CBD (common bile duct)during laparoscopic cholecystectomy. This finding may assist surgeons to perform laparoscopic cholecystectomy in less time and with less morbidity than standard laparoscopic cholecystectomy.It is expected that a successful outcome to such a trial will result in less time in the operating room and less morbidity following laparoscopic cholecystectomy.

Laparoscopic cholecystectomy is indicated for cholecystitis, biliary colic, resolved biliary pancreatitis, and symptomatic cholelithiasis. Laparoscopic cholecystectomy involves the introduction of surgical instruments through a number (usually 4) of small incisions measuring about 5-12 mm each with visual guidance being provided by means of a camera attached to an endoscope introduced through a similarly small access port. Laparoscopic techniques offer numerous benefits including a decrease in postoperative pain, some improvement in time to tolerance of food and return of bowel function, shorter hospital stay and more rapid return to normal activity.

Laparoscopic cholecystectomy is one of the most frequently performed surgical procedures in the United States. Iatrogenic bile duct injuries are a serious complication and patients undergoing the laparoscopic type of cholecystectomy are at increased risk for this complication. To minimize risk of injury, techniques such as "critical view" (dissection and visualization of the cystic duct and cystic artery) have been developed. However, adhesions, inflammation and anatomical variation can make surgical dissection and identification of significant structures difficult. In addition significantly longer operative times are seen when attempting to obtain the critical view. Some advocate the routine use of cholangiography (IOC) but the national standard of care remains to only perform IOC selectively. IOC requires cannulation of the cystic duct, injection of iodinated dye, and fluoroscopy which adds significantly to the operative time and morbidity especially in centers where routine IOC is not performed.

The present study will investigate whether the use of NIRF after injection of ICG will make identification of the Biliary structures and CBD clearer and decrease the time required to dissect out critical structures and perform safe cholecystectomy.

The SPY® Intraoperative Imaging System is cleared for use in Canada, Japan, Europe and the US. SPY was originally developed for applications in cardiac surgery and allows cardiac surgeons to visually assess bypass graft quality in real-time while the patient is still in the operating room. Subsequently, SPY has received clearance from the FDA for use in plastic and reconstructive surgery and in solid organ transplant.

The SPY Intraoperative Imaging System was originally developed for open surgical procedures using ICG, which is an FDA approved drug. ICG is a fluorescent compound, which can be administered intravenously or intra-arterially. The dye absorbs light in the near infrared (NIR) region at 806 nm, and emits light at a slightly longer wavelength, 830 nm. When injected intravenously, ICG rapidly and extensively binds to plasma proteins and is confined to the intravascular compartment with minimal leakage into the interstitium under normal conditions. ICG is taken up by the liver and then excreted into the biliary system where it can be imaged. The SPY System has been the subject of numerous peer reviewed publications demonstrating its safety .

SPY scope, the endoscopic version of SPY, is an endoscopic visible (VIS) NIR imaging system consisting of:

1. An endoscopic light source that provides illumination for visible light imaging and NIR fluorescence excitation to the endoscope via a flexible light guide
2. Rigid endoscopes optimized for illuminating the field of view and transmitting images in the visible and NIR spectrum, and
3. A high definition (HD) endoscopic camera system connected to the endoscope eyepiece and acquiring high resolution visible and NIR fluorescence images The ICG (25 mg per vial) will be reconstituted according to the manufacturer's instructions using the entire contents (10 ml) of the sterile diluent supplied, yielding a 2.5 mg/ml solution of ICG or using half of the diluent supplied (5 ml) yielding a 5 mg/ml solution.

ICG Diagnostic Procedure: 3ml of 2.5 mg/ml solution (Akorn product, US Monograph) The ICG may be administered through a peripheral venous access. Based on our prior experience in colorectal cases 1.0 ml of a 2.5 mg/ml solution of ICG (flushed with 10 ml saline) will be administered.

Our study will include patients undergoing laparoscopic cholecystectomy for both acute cholecystitis and non-acute symptomatic cholelithiasis. The standard operating technique will be used for all patients including the critical view technique and fluoroscopic IOC if clinically indicated.

Our primary endpoint will be operative time measured as the time from the beginning of the dissection until the gallbladder is separated entirely from the gall bladder fossa.

Secondary endpoints will be time to identification of structures and safety of the operation. Other endpoints such as CBD injury and postop bile leak will be included if identified.