The incidence of BDI after LC ranges from 0.3 to 2%, of cases, higher than after open cholecystectomy. This rate decreases significantly when the surgeon's laparoscopic expertise increases. Over the years, many methods have been employed to improve safety during LC, reducing this incidence to 0.08% in a recent study conducted on 156315 patients.
The unsuccessful clipping of the cystic duct stump is the first cause of minor bile leaks after LC. SVBD injury represents the 2nd one, reported up to 0.15% of cases in a large series of 1352 patients6,. The real prevalence of subvesical ducts is challenging to estimate in the general population. Ko et al. reported the incidence of ducts of Luschka as 4.6% in a study conducted on resected liver specimens. Kitami et al. described an incidence of 10% based on preoperative Drip-Infusion Cholangiography-Computed Tomography (DIC-CT) imaging of 277 patients with cholelithiasis. In a study conduct on human fetuses, the incidence of ducts of Luschka was found to be 21.9%. In his recent review, Schnelldorfer9 establishes a prevalence of SVBD from 4–10% in the general population. However, this data is probably underestimated because of the limited sensitivity of detecting these small ducts.
Preoperative study of the biliary tree anatomy and identification of its variants may be useful to detect thin ducts and avoid inadvertent injury during hepatobiliary surgery. Ultrasound is the exam of choice to study uncomplicated gallstone disease; it is easy and cheap, but it isn't able to detect minor bile ducts. Indeed, small ducts remain ignored in most patients candidates to LC for cholelithiasis. In Literature, more sensitive radiological examinations are described to evaluate bile duct variations before surgery.
Ishii performed preoperatively Drip Infusion Cholangiography with Computed Tomography (DIC-CT) to evaluate the anatomy of the biliary tree in 569 patients that underwent LC, reporting an incidence of accessory hepatic ducts in 9% of cases and an incidence of bile duct injuries in 0.7% of patients (4/569). Izuishi described the use of Multi-slice Computed Tomography (MCT) and the 3-dimensional cholangiogram before surgery, providing clear images of the aberrant bile duct in 16% of analyzed cases (18/113). Chung YH supported the use of Magnetic Resonance Cholangiopancreatography (MRCP) as a non-invasive imaging modality useful to detect the anatomical variations of the bile duct system and suggests this examination as a preoperative study. In their study, Hirao et al. compared single-slice CT scanners (SCT) cholangiography with MR cholangiography, demonstrating the superiority of SCT cholangiography over MR cholangiography to detect aberrant bile ducts. However, standard preoperative imaging cannot be performed regularly in all hospitals before LC, due to the lack of suitable equipment in some centers and the considerable increase in overall costs.
In our review, the identification of SVBD before surgery was made through CT, MRCP, or both in a total of 8 patients and the awareness of the presence of SVBD before the gallbladder dissection from its fossa allowed to avoid injury during surgery in 87.5% (7/8) of patients.
The anatomic variation could be also detected intraoperatively through contrast media injection into a bile duct. Intraoperative Cholangiography (IOC) is widely used during LC in patients suspected of having bile duct stones, but there is still no consensus of its routine use. Recently, an innovative and cheaper technique was introduced to visualize the map of the biliary tree and detect aberrant biliary ducts: Fluorescent Cholangiography (FC) by intravenous injection of Indocyanine Green (ICG) two hours before surgery. FC is based on the principle that ICG is excreted into bile and that protein-bound ICG emits fluorescent light visible when illuminated with near-infrared light. FC enables real-time identification of biliary tree and accessory hepatic ducts during the dissection of the triangle of Calot and the gallbladder fossa, allowing to detect and manage inadvertent bile duct injuries immediately. This technique was firstly described in 2008 by Ishizawa et al. and spread rapidly in hepatobiliary surgery in the last years. FC is safe and cheap, but it can be used only where infrared equipment is available. Moreover, it isn't suitable for urgent surgery. In our review, FC was performed in three cases included in Group 2.
Several causes may play a role in the incidence of leaks from SVBD, such as tissue inflammation, poor visibility of the surgical field, surgical expertise, and an incorrect dissection plane. Pericholecystic acute or chronic tissue inflammation could be responsible for a more extensive exposure of SVBD with a consequent high risk of leakage during surgery. SVBDs are located along the gallbladder's liver bed; therefore, most injuries of SVBD occur during the gallbladder dissection from its fossa. Incautious use of cautery and surgeon inexperience may lead the bed dissection in a deeper plane, causing liver parenchyma damage. For this reason, a plane of dissection close to the gallbladder is recommended to reduce the risk of biliary injury. A careful examination of the cystic bed after cholecystectomy would help to recognize leaks from an SVBD. When SVBD leak is detected intraoperatively, immediate repair is recommended to manage this complication. Many authors in this review suggest ligating the visible bile duct with a clip ; other authors chose laparoscopic suture with 3 − 0 polyglactin (Vicryl) with success. Diatermocoagulation of the bile duct isn't effective in stopping the bile spill and could worsen the parenchymal damage; therefore it should be avoided. Data extracted from studies included in the review, demonstrated that ligation or clip positioning of SVBD during surgery was performed in a total of 35 patients. However, i 14,3 % (5/35) of patients, bile leak occurred anyway.
It is important to identify the source of leak and to exactly define the kind of injury, before performing any treatment (put clip, stitches …). This should be obtained with an i.o. Cholangiography, always in case of appearance of bile in the operative field; only in this way, a cholangiography through the cistic stump, it will be possibile to exclude injury involving right hepatic ducts. In fact the aim should be to clearly understand if there is an injury of a sectorial or segmental right bile. The evidence of such injury determines the subsequent approach: in case of small peripheral bile duct closure of the duct is the treatment of choice; in case of lateral injury of a lateral sectorial duct probably the drainage of the operative field and postoperative insertion of a biliary stent should be considered mainly in young patients. In case of complete section of sectorial duct also surgical reconstruction should be evaluated.
When SVBD injury isn’t recognized intraoperatively, symptomatic minor bile leak is usually diagnosed during the first week after surgery.
The clinical presentation of bile leak changes depending on the amount of bile extravasated, the presence of infected bile, and the positioning of a drain in Morrison's space after surgery. The volume of extravasated bile depends on the caliber of the damaged duct. Usually, bile leak from the subvesical ducts has a small amount and often resolves spontaneously without any treatment, thanks to the abdominal peritoneum's capacity to absorb bile. Therefore, the real incidence of such a condition is unavailable as the asymptomatic occurrence is unknown. However, when the damaged duct is larger and connected with the central biliary tree, the extravasated bile volume may be high. It may lead to severe deterioration in the patient's condition, progressing to bile peritonitis and sepsis.
Early symptoms are generally non-specific and consist of unusual postoperative abdominal pain, nausea, vomiting, anorexia, and fever. Laboratory findings may include leukocytosis and sometimes abnormal liver function tests. According to this review, pain, fever and jaundice are the most frequent symptoms. Sometimes, cutaneous bile staining may arise around port sites and, when a drain is present, bile discharge from the tube is suggestive. If no drain is placed at the operation, a radiological examination is necessary if a bile leak is suspected as a postoperative complication. Several imaging modalities can be used to diagnose postoperative bile leaks: ultrasound (US), Computed Tomography (CT), Magnetic Resonance Imaging (MRI), and Percutaneous Transhepatic Cholangiography (PTC).
US is usually the first examination used to evaluate abnormal abdominal pain after cholecystectomy. It is helpful to measure biliary tract caliber and verify the presence of ascites or perihepatic fluid collections. Bilioma can be seen as an anechoic well-circumscribed fluid collection, and when detected, a second-line radiological exam is required. DIC-CT is a rapid examination, can measure the amount and density of free fluid collection, and exclude a major biliary injury evaluating biliary flow. Disadvantages of DIC-CT are the use of radiation and contrast media that can cause adverse reactions after injection. The source of biliary leakage can be demonstrated by MRI too. MRCP allows to distinguish between fluid collections of biliary and non-biliary origin and detects with high sensitivity and specificity leaks not communicating with the central biliary tree such as from SVBD. MRCP has a longer scanning time than DIC-CT, but it is non-invasive and detects biliary injury without intravenous contrast media.
Direct cholangiography can be performed via PTC, which requests an intrahepatic bile duct puncture through the abdominal wall and liver parenchyma; X-ray images are taken during injection of a contrast media. This radiological technique allows to visualize precisely the site of the bile leak, detecting the discharge of contrast media from the biliary tree. Sometimes, transhepatic drainage could be positioned into the biliary duct to drain the bile outside and accelerate the healing.
Cholangiogram can be also done during Endoscopic Retrograde Cholangiopancreatography (ERCP). ERCP detects the bile leak site in more than 95% of cases and has both a diagnostic and therapeutic role.
Treatment of minor bile leak is multidisciplinary and may include conservative management, endoscopic procedures, percutaneous drainage, and in rare cases, surgery.
When the bile leak causes a small intra-abdominal bilioma, a conservative approach is feasible if the patient's conditions are stable and symptoms are mild. In these cases, repeated radiological monitoring of the hepatobiliary system is essential to evaluate bilioma size and exclude other complications.
Otherwise, bile could be drained outside the abdominal cavity through a percutaneous drainage positioning under the assistance of US or CT. The drainage should stay in place until the bile output decreases and the patient's clinical condition and radiological imagines improve.
Endoscopic management is considered the gold standard treatment in case of a minor bile leak. Sphincterotomy and biliary stent placement reduce the transpapillary pressure gradient through the sphincter of Oddi between the biliary tract and the duodenum, favoring drainage of bile into the gastrointestinal tract. Low pressure on the leakage site promotes the healing and closure of the defect, with a clinical success rate reported in the Literature > 90%. The decision to perform biliary sphincterotomy and/or stent placement is at the endoscopist's discretion. Chandra et al. described 23 patients with bile leak from the duct of Luschka treated with endoscopic procedures with a success rate of 100% of cases; only 5 patients required stent positioning. In his study, endoscopic biliary sphincterotomy alone without stenting is considered the fastest method to manage the bile leak with good outcomes. In fact, stent placement requires a second endoscopy for stent removal. Whereas, Keffles et al. in a study on 100 patients, supported that the optimal intervention for post-cholecystectomy bile leak should include temporary insertion of a biliary stent. Shanda et al. proposed sphincterotomy alone for patients with a low-grade leak and stent placement in patients with a high-grade leak. In our review, 124 patients (79.5%) achieved clinical success with endoscopic procedures, without any need for further invasive procedures.
If ERCP is not possible or fails, the Percutaneous Transhepatic Drainage (PTCD) is the alternative approach17. This radiological intervention consists of the bile diversion away from the site of ductal injury to promote fast healing.
Surgery approach is controversial. Some authors - consider re-laparoscopy an effective procedure in managing minor bile leakage after LC and used surgery as the first-line treatment in selected healthy patients without jaundice. Laparoscopic aspiration of leaked bile and lavage of the abdominal cavity are more effective than percutaneous drainage, accelerating patient healing with a shorter hospital stay. Advantages are that surgery can be performed by a surgeon without the help of other departments. Most authors assert that surgical reintervention should be reserved only for patients with clinical deterioration caused by significant bile duct injury and massive leak. Naturally, surgery should be recommended in the most serious cases, when mini-invasive procedures aren’t resolutive.
Another possibility is that injury involves peripheral ducts that can be lose their connection with main biliary tree. In these cases, it is important to evaluate the amount of liver parenchyma related to an un-connected bile duct. If the amount of parenchyma is small, closure of the bile duct with clip or stitches and external surgical drainage should be preferred. In case of recurrent leak through the drain, waiting for closure of fistula and atrophy of the parenchyma is preferable. When on the contrary the amount of parenchyma is not negligible, for example right posterior sector, biliary surgical reconstruction can be considered.