Biliary Fistula (BF) is a common complication after hepatic resection. With drainage, it often resolves spontaneously, but can sometimes be intractable [1, 2]. Persistent BF can lead to serious complications such as intra-abdominal infection. In 2011, the International Study Group of Liver Surgery (ISGLS) [3] indicated that a diagnosis of post-hepatectomy BF could be made in cases with “a bilirubin level greater than three times the serum bilirubin level that persists for more than three days post-operatively.” ISGLS defines BF after hepatectomy as “a bile accumulation or biliary peritonitis.” The ISGLS BF severity classifications are grade A, no treatment; grade B, treatment other than re-operation; or grade C, re-operation. Although various efforts have been made to reduce the rate of BF, the incidence of BF is still relatively high, ranging from 4–24% [4, 5, 6], and Hayashi et al. [7] recently reported an association between intraoperative bile leakage (BL) detection and postoperative BF.
Intraoperative BL testing after hepatectomies is a longstanding practice used to detect bile duct injuries and prevent BFs. A meta-analysis of clinical trials found that the BL test reduces the incidence of BF [8]. A study of 101 central hepatectomies reported that BL was identified intraoperatively in 41.6% of patients, postoperative BF was identified in 23.8% of the patients despite intraoperative repair, and the incidence of postoperative BF was 5.1% in the remaining group without intraoperative BL [6]. These results suggest that the BL test and intraoperative BL detection are important for preventing BFs. However, the test cannot detect BL from those bile ducts that do not communicate with the common bile duct such as Nagano’s type D bile duct [9] or Strasberg’s type C bile duct injuries [10]. In addition, the test is hard to perform in patients who have not undergone cholecystectomy alongside hepatectomy, as the catheter used to inject the dye solution into bile ducts cannot be cannulated. Therefore, there is a need to develop a new test that is easier to use and that can detect all types of BL in all surgical procedures.
Intra-biliary infusion of indocyanine green (ICG) can be used for observation of the hepatic resection site. However, at the current time in Japan, this is not covered by public health insurance. Fortunately, since 2018, insurance has covered the use of ICG camera observation of the resection area to evaluate hepatic blood flow and determine the demarcation line [11]. While using ICG for this purpose in our clinical practice, we noticed that ICG leakage could be observed more sensitively with an ICG camera than with the naked eye after liver resection is complete (Fig. 1ab).
Previous studies have established that systemic administration of ICG improves the sensitivity with which bile duct secretion can be detected [12]. In this study, we utilized the excretion of ICG into bile after its systemic administration to retrospectively observe whether treatment of BL based on its detection using ICG fluorescence in liver section planes reduces drainage fluid bilirubin levels more than treatment based on conventional BL detection through observation alone. The primary outcome was the presence or absence of a reduction in drainage fluid bilirubin levels in the ICG observation group (IO-G) compared to the conventional observation group (CO-G). In addition, we reviewed surgical videos of IO-G patients and compared the number of BL spots in resection planes that were visible to the naked eye with the number of ICG fluorescence spots visible on an ICG camera.