Laparoscopic cholecystectomy for a gallbladder with a short cystic duct draining to the accessory right anterior hepatic duct using indocyanine green fluorescence imaging: A case report.

INTRODUCTION: Gallbladder with a short cystic duct draining to the accessory right anterior hepatic duct is a rare variation. It is frequently associated with bile duct injury during laparoscopic cholecystectomy. We present a case of a gallbladder with this variation safely treated with laparoscopic cholecystectomy using indocyanine green (ICG) fluorescence imaging. PRESENTATION OF CASE: A 57-year-old man had right upper quadrant pain and showed a gallbladder stone on a preoperative computed tomography. Bile duct anomaly was not detected before operation. However, a short cystic duct draining to the accessory right anterior hepatic duct intraoperatively was found using ICG fluorescence imaging. To confirm the exact anatomy, we firstly detached the gallbladder from the liver with a "fundus first technique" and visualized the whole course of the short cystic duct and the accessory right anterior with ICG fluorescence imaging. Laparoscopic cholecystectomy was completed safely. No bile leakage was detected on ICG fluorescence imaging. The patient had no postoperative complication. DISCUSSION: Accessory right hepatic duct is one of the rare variations of bile duct. It can be related to bile duct injury during laparoscopic cholecystectomy. Although it can be injured easily because of its smaller size, we can identify the short cystic duct from it with the aid of ICG fluorescence imaging without injuring the accessory right anterior hepatic duct. CONCLUSION: Laparoscopic cholecystectomy for gallbladder with a short cystic duct draining to the accessory right anterior hepatic duct can be safely performed by identifying biliary anatomy with ICG fluorescence imaging.

CT Evaluation of Long-Term Changes in Common Bile Duct Diameter after Cholecystectomy.

Purpose: The present study aimed to investigate the frequency and extent of compensatory common bile duct (CBD) dilatation after cholecystectomy, assess the time between cholecystectomy and CBD dilatation, and identify potentially useful CT findings suggestive of obstructive CBD dilatation. Materials and Methods: This retrospective study included 121 patients without biliary obstruction who underwent multiple CT scans before and after cholecystectomy at a single center between 2009 and 2011. The maximum short-axis diameters of the CBD and intrahepatic duct (IHD) were measured on each CT scan. In addition, the clinical and CT findings of 11 patients who were initially excluded from the study because of CBD stones or periampullary tumors were examined to identify distinguishing features between obstructive and non-obstructive CBD dilatation after cholecystectomy. Results: The mean (standard deviation) short-axis maximum CBD diameter of 121 patients was 5.6 (± 1.9) mm in the axial plane before cholecystectomy but increased to 7.9 (± 2.6) mm after cholecystectomy (p < 0.001). Of the 106 patients with a pre-cholecystectomy axial CBD diameter of < 8 mm, 39 (36.8%) showed CBD dilatation of ≥ 8 mm after cholecystectomy. Six of the 17 patients with longterm (> 2 years) serial follow-up CT scans (35.3%) eventually showed a significant (> 1.5-fold) increase in the axial CBD diameter, all within two years after cholecystectomy. Of the 121 patients without obstruction or related symptoms, only one patient (0.1%) showed IHD dilatation > 3 mm after cholecystectomy. In contrast, all 11 patients with CBD obstruction had abdominal pain and abnormal laboratory indices, and 81.8% (9/11) had significant dilatation of the IHD and CBD. Conclusion: Compensatory non-obstructive CBD dilatation commonly occurs after cholecystectomy to a similar extent as obstructive dilatation. However, the presence of relevant symptoms, significant IHD dilatation, or further CBD dilatation 2-3 years after cholecystectomy should raise suspicion of CBD obstruction.

Normal morphometry of the biliary tree in pediatric and adult populations: A systematic review and meta-analysis.

PURPOSE: This study aimed to characterise the normal morphometry of the biliary tree in pediatric and adult populations, through a systematic review and meta-analysis. METHODS: This study, conducted using the PRISMA guidelines and registered with PROSPERO, searched MEDLINE, EMBASE, SCOPUS and Web of Science databases up to October 2022, and updated to August 2023. Studies that reported extractable data on diameter and length of the right, left and common hepatic ducts (LHD, RHD and CHD), and common bile duct (CBD) were included. Quality of the included studies were assessed using the Anatomical Quality Assessment (AQUA) tool. Statistical analysis included subgroup analyses according to sex, age, geographical location, and imaging modality. RESULTS: In total, 60 studies were included, of which 44 studies reported adequate data for meta-analysis on 23,796 subjects. Overall, the pooled mean diameter of the CBD was 4.69 mm (95 % CI: 4.28-5.11). Significant differences were found between pediatric (1.32 mm, 95 % CI: 1.03-1.61) and adult (4.97 mm, 95 % CI: 4.67-5.27) subjects, as well as US (3.82 mm, 95 % CI: 3.15-4.49) and other imaging modalities, including MRI (6.21 mm, 95 % CI: 4.85-7.57) and ERCP (7.24 mm, 95 % CI: 6.08-8.40). The CBD diameter measured significantly larger distally (5.20 mm, 95 % CI: 4.60-5.80) than proximally (4.01 mm, 95 % CI: 3.51-4.51). CONCLUSIONS: The results obtained from this evidence-based study may guide the establishment of standardised reference values and ranges of the normal biliary tree in pediatric and adult populations and aid clinical understanding.

Hepatic Duct Adenoma Identified Using Direct Cholangioscopy.

Bile duct adenomas (BDAs) are rare benign tumors that can arise in the intra-hepatic or extra-hepatic biliary tree. We present a case of a 46-year-old female who presented with symptoms suggestive of choledocholithiasis. Direct cholangioscopy identified a 15 mm polypoid lesion in the common hepatic duct (CHD). Biopsy revealed a BDA. We present this case to highlight the role of direct cholangioscopy in the diagnosis and management of BDAs.

Retroperitoneal biloma-A rare differential diagnosis of perirenal fluid accumulation.

Introduction: Nontraumatic biliary rupture and retroperitoneal biloma infrequently occur. Here, we report a case of retroperitoneal biloma due to spontaneous left hepatic duct perforation, which was difficult to differentiate from a perirenal abscess. Case presentation: A 94-year-old female patient was hospitalized with symptoms of fatigue and right back pain that lasted for 5 days. Computed tomography revealed fluid accumulation in the retroperitoneum, and urinary extravasation and right perinephric abscess were suspected. Antimicrobial treatment and drainage with ureteral stents and urethral catheters demonstrated no symptom improvement. Ultrasound-guided puncture of the abscess revealed the presence of bile. Pigtail catheter drainage improved symptoms and inflammatory response. After diagnosis, endoscopic retrograde cholangiopancreatography revealed bile leakage, and a bile duct stent was inserted. Conclusion: Biloma can cause perirenal fluid accumulation, and they should be considered an origin of perirenal fluid accumulation when urinary tract lesions are excluded.

Giant bile duct dilatation in newborn: A case report.

BACKGROUND: Giant congenital biliary dilation (CBD) is a rare condition observed in clinical practice. Infants born with this condition often experience a poor overall health status, and the disease progresses rapidly, leading to severe biliary obstruction, infections, pressure exerted by the enlarged CBD on abdominal organs, disturbances in the internal environment, and multiple organ dysfunction. The treatment of giant CBD using laparoscopy is challenging due to the high degree of variation in the shape of the bile duct and other organs, making it difficult to separate the bile duct wall from adjacent tissues or to control bleeding. CASE SUMMARY: Herein, we present the details of an 11-d-old male newborn who was diagnosed with giant CBD. The patient was admitted to the neonatal surgery department of our hospital due to a history of common bile duct cyst that was detected more than 3 mo ago, and also because the patient had been experiencing yellowish skin for the past 9 d. The abnormal echo in the fetal abdomen was first noticed by the patient's mother during a routine ultrasound examination at a local hospital, when the patient was at 24 wk + 6 d of pregnancy. This finding raised concerns about the possibility of congenital biliary dilatation (22 mm × 21 mm). Subsequent ultrasound examinations at different hospitals consistently confirmed the presence of a congenital biliary dilatation. No specific treatment was administered for biliary dilatation during this period. A computed tomography scan conducted during the hospitalization revealed a large cystic mass in the right upper quadrant and pelvis, measuring approximately 9.2 cm × 7.4 cm × 11.3 cm. Based on the scan, it was classified as a type I biliary dilatation. CONCLUSION: The analysis reveals that prenatal imaging techniques, such as ultrasound and magnetic resonance imaging, play a crucial role in the early diagnosis, fetal prognosis, and treatment plan for giant CBD. Laparoscopic surgery for giant CBD presents certain challenges, including difficulties in separating the cyst wall, anastomosis, and hemostasis, as well as severe biliary system infection and ulceration. Consequently, there is a high likelihood of converting to laparotomy. The choice between surgical methods like hepaticojejunostomy (HJ) or hepaticoduodenostomy has not been standardized yet. However, we have achieved favorable outcomes using HJ. Preoperative management of inflammation, biliary drainage, liver function protection, and supportive treatment are particularly vital in improving children's prognosis. After discharge, it is essential to conduct timely reexamination and close follow-up to identify potential complications.

Successful Laparoscopic Hepaticojejunostomy for Infant Congenital Biliary Dilatation with both Aberrant Right Hepatic Artery and Bile Duct from the Caudate Region.

A boy with congenital hydronephrosis underwent ultrasonography every month for follow-up. At 4 months of age, ultrasonography incidentally revealed congenital biliary dilatation (5-cm type Ia). We performed laparoscopic extrahepatic bile duct resection and hepaticojejunostomy. After dissecting the dilated common bile duct (CBD), we found that the arcading-like shaped right hepatic artery (RHA) coursed in front of the CBD. Additionally, a tiny duct was identified below the main hepatic duct. At first, we thought it was a lymphatic vessel and dissected it from the main hepatic duct. However, bile flow out was recognized after dissecting the tiny duct. Finally, we confirmed it as an aberrant bile duct from the caudate region. We anastomosed the bile duct from the caudate region and main hepatic duct in a double-barrel fashion and performed hepaticojejunostomy below the RHA. The postoperative course was uneventful. Ultrasonography showed no intrahepatic ductal dilatation including the caudate lobe.

The management of a duodenal fistula involving the right hepatic duct: a rare case report.

The formation of an internal fistula between the biliary system and the gastrointestinal tract is a rare condition with various etiologies, predominantly associated with recurrent chronic inflammation of the biliary system and tumors. Patients with this condition may lack specific clinical manifestations, presenting with symptoms such as abdominal pain, fever, jaundice, or may show no clinical signs at all. Common types of internal fistulas include cholecystoduodenal fistula, cholecystocolonic fistula, and choledochoduodenal fistula. Among these, the right hepaticoduodenal fistula is extremely rare and seldom reported in clinical literature. We herein report a case of right hepaticoduodenal fistula and analyze its mechanism, treatment principles, and preventive measures through a literature review.

Variations in the cystic duct: frequency and the relationship among insertion sides and heights on the bile duct.

BACKGROUND: Evaluation of the cystic duct anatomy prior to bile duct or gallbladder surgery is important, to decrease the risk of bile duct injury. This study aimed to clarify the frequency of cystic duct variations and the relationship between them. METHODS: Data of 205 patients who underwent cholecystectomy after imaging at Sada Hospital, Japan, were analyzed. The Chi-square test was used to analyze the relationships among variations. RESULTS: The lateral and posterior sides of the bile duct were the two most common insertion points (92 patients, 44.9%), and the middle height was the most common insertion height (135 patients, 65.9%). Clinically important variations (spiral courses, parallel courses, low insertions, and right hepatic duct draining) relating to the risk of bile duct injury were observed in 24 patients (11.7%). Regarding the relationship between the insertion sides and heights, we noticed that the posterior insertion frequently existed in low insertions (75.0%, P < 0.001) and did not exist in high insertions. In contrast, the anterior insertion coexisted with high and never low insertions. Spiral courses have two courses: anterior and posterior, and anterior ones were only found in high insertion cases. CONCLUSIONS: The insertion point of the cystic duct and the spiral courses tended to be anterior or lateral superiorly and posterior inferiorly. Clinically significant variations in cystic duct insertions are common and surgeons should be cautious about these variations to avoid complications.

An unusual presentation of a rare formation of the common hepatic duct and right hepatic artery in a case of pediatric congenital biliary dilatation.

A 15-year-old girl with recurrent upper abdominal pain was diagnosed with congenital biliary dilatation. Abdominal enhanced computed tomography (CT) showed the anterior segmental branch of the right hepatic artery (RHA) running across the ventral aspect of the dilated common hepatic duct (CHD). Laparoscopic extrahepatic dilated biliary duct excision and Roux-en-Y hepaticojejunostomy were planned. Intraoperatively, the dilated CHD was observed to bifurcate into the ventral and dorsal ducts, between which the anterior segmental branch of the RHA crossed through the CHD. The CHD rejoined on the distal side as one duct. We transected the CHD just above the cystic duct. The patency of the ventral and dorsal sides of the bifurcated CHD was confirmed. Laparoscopic hepaticojejunostomy was performed at the distal side of the rejoined CHD, without sacrificing the anterior segmental branch of the RHA. There was no postoperative blood flow impairment in the right hepatic lobe or anastomotic stenosis.

Protective strategy for the caudate lobe bile duct during left hemihepatectomy based on imaging data analysis.

Purpose: This study was performed to analyze the rule of confluence of the caudate lobe bile duct (CLD) into the left hepatic duct (LHD) and to discuss the protective strategy during left hemihepatectomy. Methods: MRI of 400 patients and T-tube angiography images of 100 patients were collected, and the imaging rules of the confluence of the CLD into the LHD were summarized. The clinical data of 33 patients who underwent left hemihepatectomy using the protective strategy were analyzed. Results: MRI and T-tube angiography images showed that the length from the confluence point of the CLD into the LHD to the confluence of the left and right hepatic ducts was 1.19 ± 0.40 cm and 1.26 ± 0.39 cm, respectively. The average angle between the longitudinal axis of the 2 bile ducts was 68.27° ± 22.59° and 66.58 ± 22.88°, respectively. Coronal and cross-sectional images showed that inflow from the foot side to the cranial side was noted in 79.8% and 82.0% of patients, respectively, and inflow from the dorsal to the ventral side was observed in 84.5% and 88.0%, respectively. Based on these imaging rules, the safe transection length and plane were summarized, and the CLD was effectively protected in 33 cases of left hemihepatectomy. Conclusion: In left hemihepatectomy, the LHD should be transected at least 1.5 cm away from the confluence of the left and right hepatic ducts, and the plane of transection should be oblique to the dorsal side at an angle of 45° with the LHD, these parameters represent an effective strategy to protect the CLD.

Prospective evaluation of common hepatic duct histopathology at the time of choledochal cyst excision ranging from children to adults.

PURPOSE: To evaluate common hepatic duct just distal to the HE anastomosis (d-CHD) prospectively for mucosal damage, inflammation, fibrosis, dysplasia, carcinoma in situ, malignant transformation, effects of serum amylase, and symptoms at presentation in CC cases ranging from children to adults. METHODS: Cross-sections of d-CHD obtained at cyst excision 2018-2023 from 65 CC patients; 40 children (< 15 years old), 25 adults (≥ 15) were examined with hematoxylin and eosin, Ki-67, S100P, IMP3, p53, and Masson's trichrome to determine an inflammation score (IS), fibrosis score (FS), and damaged mucosa rate (DMR; damaged mucosa expressed as a percentage of the internal circumference). RESULTS: Mean age at cyst excision ("age") was 18.2 years (range: 3 months-74 years). Significant inverse correlations were found for age and DMR (p = 0.002), age and IS (p = 0.011), and age and Ki-67 (p = 0.01). FS did not correlate with age (p = 0.32) despite significantly increased IS in children. Dysplasia was identified in a 4-month-old girl with cystic CC. Serum amylase was elevated in high DMR subjects. CONCLUSIONS: High DMR, high IS, and evidence of dysplasia in pediatric CC suggest children are at risk for serious sequelae best managed by precise histopathology, protocolized follow-up, and awareness that premalignant histopathology can arise in infancy.

Cystic duct entering to right hepatic duct; a case report with literature review.

INTRODUCTION AND IMPORTANCE: Surgeons may mistakenly consider the right hepatic duct as cystic duct, ligate, and divide it. CASE PRESENTATION: A 58-year-old woman presented with right upper quadrant (RUQ) abdominal pain, nausea, and RUQ tenderness, but negative Murphy's sign. Common bile duct was 10 mm based on abdominal ultrasound. Common hepatic duct and intrahepatic ducts consist of multiple common bile duct (CBD) stones with sludge and multiple small gallstones. Different diagnostic procedures (Computed tomography (CT) scan, magnetic resonance cholangiopancreatography (MRCP), and endoscopic retrograde cholangiopancreatography (ERCP)) showed the connection of the cystic duct to the right hepatic duct. Balloon sweeping for stones extraction and then laparoscopic cholecystectomy was successfully done. CLINICAL DISCUSSION: Radiologic evaluations like MRCP, CT scan, ERCP or sonography before or during the surgery/endoscopic interventions seem logical at least for selected patients. CONCLUSION: Before endoscopic/surgical interventions we need to be sure about the anatomy of biliary tree by a suitable para-clinic evaluation.

Exploring the imaging features and treatment options of Mirizzi syndrome.

The patient is a 54-year-old female who presented to the emergency department for episodic right biliary colic with nausea and vomiting over the past year. The patient's symptoms warranted multiple emergency department visits, but were self-limiting. During the most recent visit, the patient had a low-grade fever of 99.8°F (96.8°F-99.5°F) and a borderline elevated total bilirubin of 1.2 (0.2-1.2 mg/dL). Abdominal ultrasound revealed cholelithiasis, gallbladder wall thickening, and biliary ductal dilatation. Subsequent MRCP revealed an impacted stone within the gallbladder neck and a prominent common hepatic duct, compatible with Mirizzi syndrome Type I. The obtained imaging combined with clinical correlation in the setting of jaundice and right upper quadrant pain guided the patient's management. A laparoscopic cholecystectomy was performed and the patient was safely discharged the following day.

Percutaneous Management of Hepatic Duct Injury Using Extra-Anatomic Biliary Catheters.

Iatrogenic bile duct injury during laparoscopic cholecystectomy is a known complication of low incidence. The outcome can be devastating if not recognized and managed timely and properly. In cases of iatrogenic biliary injury due to cholecystectomy, the management depends on the level of injury, the timing of discovery (intraoperative or postoperative), and the patient's condition. If discovered intraoperatively, the injury should be managed immediately. In case expertise is lacking, a surgical drain with external biliary drainage can provide a temporary alternative solution to allow for referral to a tertiary care center. If the patient is septic or not fit for surgery, a percutaneous internal-external biliary drainage (PTBD) catheter can be placed until the patient's condition improves. We report a case of complete transection of the common hepatic duct during laparoscopic cholecystectomy managed by extra-anatomic PTBD.

A case of accessory hepatic duct entering cystic duct successfully treated by laparoscopic cholecystectomy for cholecystolithiasis.

Although laparoscopic cholecystectomy is a well-established surgical procedure, an accessory hepatic duct (AcHD) entering the cystic duct is poorly understood. A 77-year-old woman with symptomatic cholecystlithiasis was referred to our hospital. Abdominal ultrasonography indicated several small stones in the gall bladder. Magnetic resonance cholangiopancreatography (MRCP) did not reveal an anomalous cystic duct. Dissecting the gall bladder bed at operation, AcHD entering the cystic duct was suspected. Intraoperative cholangiography revealed that B5 branch entered the cystic duct. We ligated the AcHD, and divided it. Laparoscopic cholecystectomy was completed, and the patient was discharged without any complication. A week after the operation, MRCP showed that ventral branch of B5 was dilated. The patient showed no symptom for more than a year. The present case exhibited extremely rare AcHD entering the cystic duct, which was hardly recognized before surgery. It is possible to recognize such anomalous variants with standard laparoscopic approach based on 2018 Tokyo Guidelines and with attention to the possibilities of AcHD entering the cystic duct.

Biliary Atresia Remnants Revisited: Myogenesis, Hepatic Duct-Like Structures, and Fate of Peribiliary Glands.

PURPOSE AND CONTEXT: Proximal levels of excised remnants from youngest infants may reveal early features of biliary atresia (BA). METHOD: A targeted IHC survey was applied to 34 most proximal 2 levels in 17 BA remnants excised at age 10-74 days including 7 = <30 days old and 6 control hepatic ducts (HD). KEY RESULTS: Severity of inflammation and extent of active fibroplasia do not distinguish proximal remnants in younger (n = 7) and older (n = 10) infants. In 27/34 levels of 14/17 remnants, reactive stroma is focally SM-MHC-2 (+), marking smooth muscle myosin, termed reactive myogenesis (RM), that is absent in controls. RM facilitates identification of 3 novel hepatic duct remnants (HDR): an HD-like collagen collar lined by degenerating cholangiocytes (n = 5); erosion defects in loose reactive stroma (n = 14); solitary foci of hyperplastic squamoid epithelium (n = 4). Peribiliary glands are either hyperplastic or atretic and typically lack RM. CONCLUSION: Minimally inflammed end-stage lesions in BA remnants occur at youngest ages favoring prenatal onset. Three novel HDR are defined. RM, a useful surrogate for HDR, is a prevalent inappropriate stromal reaction in proximal remnants of uncertain biological significance. RM is the source of mature smooth muscle in BA remnants.

Embolization of an incomplete isolated right segmental hepatic duct injury (incomplete IRSHDI)-A case report.

Iatrogenic bile duct injuries remain a substantial problem in gastrointestinal surgery, especially if discovered later in the postoperative period. Herein, we report a case of an unusual bile leak following laparoscopic cholecystectomy consisting of an isolated right segmental hepatic duct injury of segment 5 together with an additional bile leak of a small duct connecting the gallbladder fossa with the common bile duct. We call this situation an incomplete isolated right segmental hepatic duct injury. Patient presented with infected biloma 2 weeks after laparoscopic cholecystectomy. After percutaneous drainage of the biloma and antibiotic therapy the complex biliary fistula was closed first with coil embolization of the small connection to the common bile duct and then with both antegrade and retrograde histoacryl embolization of the hereby created complete isolated right segmental hepatic duct injury in a single session. Patient was discharged the same day and recovered without complication or recurrence.

Post cholecystectomy benign biliary stricture-isolated hepatic duct stricture: a proposed modification of the BISMUTH classification.

BACKGROUND: Post-cholecystectomy, benign biliary strictures are challenging for both patients and surgeons. Bismuth classified benign biliary strictures into 5 types. This study aimed to review these isolated hepatic duct strictures which were not included in Bismuth classification. METHODS: The case records of all patients who presented with post-cholecystectomy benign biliary strictures between January 2005 and December 2020 at our centre were reviewed. Data regarding demography, type of stricture, and treatment strategy were entered into the standard proforma. RESULTS: There were 242 patients [type I-3.7%, type II-41.7%, type III-38.0%, type IV-6.6%, and type V-7.8%]. Five (2.1%) patients did not fit the Bismuth classification and were the focus of this study. In each of these patients, an isolated hepatic duct stricture (first-or second-order hepatic duct) was present, with no involvement of the common hepatic duct or hilar confluence. CONCLUSIONS: The addition of isolated hepatic duct stricture [type VI] to the Bismuth classification will enhance the original classification, help in reporting and management of this sub-set of patients.

Fluorescence cholangiography for detection of a cystic duct drained into an accessory hepatic duct: A case report.

INTRODUCTION: Laparoscopic cholecystectomy is a safe and standard procedure, but serious bile duct injury may occur due to anatomical anomalies of the biliary tract, especially the accessory hepatic duct. The use of intraoperative fluorescence cholangiography with indocyanine green during laparoscopic cholecystectomy can reportedly prevent bile duct injury. PRESENTATION OF CASE: A 55-year-old woman with upper abdominal pain was referred to our hospital. Laboratory investigations revealed elevated leukocytes and biliary enzymes, while computed tomography demonstrated increased fatty tissue density around the gallbladder. Magnetic resonance cholangiopancreatography and drip infusion cholangiographic-computed tomography showed that the cystic duct drained into an accessory hepatic duct. Due to the diagnosis of cholelithiasis with a biliary anomaly, we performed laparoscopic cholecystectomy using fluorescence cholangiography with indocyanine green. We were able to recognize the accessory hepatic duct and cystic duct, then safely dissect the cystic duct without bile duct injury. DISCUSSION: Laparoscopic cholecystectomy is generally regarded as a safe procedure, but complications and even mortalities can arise in patients with anatomical anomalies of the biliary tract. The aid of intraoperative fluorescence cholangiography with indocyanine green allowed to recognize and identify the accessory hepatic duct and cystic duct, allowing us to operate without injury to the bile duct. CONCLUSIONS: Our experience supports the ease of use, safety, and effectivity of fluorescence cholangiography with indocyanine green. This may become the optimal standard technique to prevent bile duct injury.