The diseased bile duct in bilobar congenital biliary dilatation is extensive and often requires major hepatectomy or liver transplantation associated with a higher risk. We aimed to evaluate the safety and benefit of modified mesohepatectomy, in comparison with trisectionectomy, to treat bilobar congenital biliary dilatation.
This study included 28 patients with type IV and V bilobar congenital biliary dilatation. An innovative mesohepatectomy comprising the hepatectomy technique beyond the P/U point and bile duct shaping was applied to 14 patients to address the extensively diseased bile duct and difficulty in hepaticojejunostomy. Another 14 patients received trisectionectomy. The perioperative and long-term outcomes of these patients were compared.
The ratio of residual liver volume to standard liver volume in the mesohepatectomy group was higher (78.68% vs. 40.90%, p = 0.005), while the resection rate of the liver parenchyma was lower (28.25% vs. 63.97%, p = 0.000), than that in trisectionectomy group. The mesohepatectomy group had a lower severe complication (>Clavein III, 0% vs. 57.70%, p = 0.019) and incidence of posthepatectomy liver failure (7.14% vs. 42.86%, p = 0.038). No significant difference was observed in blood loss and bile leakage (p > 0.05). All the patients in the mesohepatectomy group achieved optimal results in the long-term follow-up.
mesohepatectomy provides an efficient treatment option for bilobar congenital biliary dilatation and can achieve radical resection, retain more liver parenchyma, and reduce the difficulty of hepaticojejunostomy, especially for patients that are not eligible for major hepatectomy and liver transplantation.

BACKGROUND: This study aimed to reveal the early and late postoperative complications and outcomes after surgery for congenital biliary dilatation (CBD) by reviewing cases over the past 40 years.
METHODS: We retrospectively evaluated 59 patients with CBD who underwent radical surgery for complications and outcomes, based on medical records. Early complications were defined as those requiring treatment within 5 years of the initial operation. Late complications were defined as those treated more than 5 years later.
RESULTS: The median age at the first surgery was 37 months. Regarding biliary reconstruction, 54 of the 59 patients (91.5%) underwent hepaticojejunostomy. Although three patients underwent cholecystoduodenostomy and one patient underwent hepaticoduodenostomy, all were converted to hepaticojejunostomy after a median of 12.5 years. One patient developed synchronous biliary carcinoma and underwent pancreaticoduodenectomy. Early complications occurred in seven patients with 10 events (surgical site infection, n = 3 bile leakage, n = 3; ileus, n = 3; bile duct obstruction, n = 1 and intussusception, n = 1). Late complications occurred in nine patients with 12 events (ileus, n = 3; anastomotic stricture, n = 3; hepatolithiasis, n = 3; asynchronous biliary carcinoma, n = 2; pancreatolithiasis, n = 1). Two of the three patients with hepatolithiasis underwent hepatectomy refractory to the endoscopic approach. Two patients developed asynchronous biliary carcinoma at 34 and 13 years after last operation; both ultimately died of the carcinoma. Only 35 patients (61.4%) underwent a follow-up examination. A total of 11 female patients (45.8%) eventually married, and all successfully gave birth.
CONCLUSIONS: Although the long-term prognosis is excellent with complete cyst excision and hepaticojejunostomy, we emphasize the importance of long-term follow-up.

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.

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.

OBJECTIVE: The aim of the study is to clarify the clinicopathological and biliary morphological characteristics in reported cases of diverticular congenital biliary dilatation (CBD).
METHODS: Using PubMed and the Japan Medical Abstracts Society, articles on possible diverticular CBD were extracted and the clinical pictures examined. We also sought evidence for definitions of diverticular CBD and the associated condition of pancreaticobiliary maljunction (PBM) using the original articles by Alonso-Lej and Todani. The characteristic biliary morphologies of cases with images were also investigated.
RESULTS: Analyses of 211 possible cases superficially demonstrated multiple diverticula in 12 (12%) and single diverticulum in 89 (88%), with diverticula located in the upper (n = 38, 38%), middle (n = 32, 32%), or lower (n = 26, 26%) biliary tract in and presence of intra-diverticular stones, PBM, and biliary carcinoma in 23% (n = 18), 39% (n = 25), and 11% (n = 14), respectively. However, evidence defining diverticular CBD or justifying the lack of associated PBM was not demonstrated even in the original articles. Scrutiny of the biliary anatomy in 59 cases with images showed incorrect inclusions of types I or IV-A with an irregular biliary duct wall or dilated cystic duct, periampullary choledochal diverticula, or even solitary biliary cysts. Authentic diverticular CBD, representing the diverticulum connected to the middle of the common bile duct via a thin, patent stalk was seen in only 6 cases.
CONCLUSIONS: Real diverticular CBD appears extremely rare. The lack of an objective definition allows wide interpretations of clinical pictures, creating inconsistencies in the diagnosis and treatment of CBD and raising questions regarding the utility of conventional classifications.
METHODS: Level III.

BACKGROUND: This study aimed to develop a postnatal treatment strategy for infants with prenatally diagnosed congenital biliary dilatation.
METHODS: We performed a retrospective study of patients with prenatal diagnosed congenital biliary dilatation (CBD), aged <1 year who underwent surgery at our hospital between 2013 and 2023. We classified the patients into two groups, the \"early group,\" consisting of patients who could not wait for growth, and required early surgery, and the \"scheduled group,\" consisting of patients who were asymptomatic and could undergo scheduled surgery, and compared them. The parameters for early surgical prediction were AST, ALT, TB, DB, and CRP levels at birth, 1 week, 2 weeks, 1 month, 2 months, and 3 months after birth, and immediately before surgery, as well as the cyst diameter, presence of intrahepatic bile duct dilation, and presence of debris in the common bile duct.
RESULTS: During the study period, 15 patients were diagnosed prenatally. The cyst diameter was significantly larger at all points in the early group. Patients with a cyst diameter of >30 mm at birth, intrahepatic bile duct dilatation at birth, and postnatal enlargement of the common bile duct to >30 mm are more likely to develop symptoms early. Blood biochemistry tests showed no significant differences between the two groups.
CONCLUSIONS: Patients with a cyst diameter >30 mm in the early postnatal period require careful postnatal management and parents should be counseled regarding the high likelihood of their child needing surgery within the first 3 months of life.
METHODS: Level IV.

OBJECTIVE: Congenital biliary dilatation (CBD) is a bile duct malformation often associated with pancreaticobiliary maljunction. Different subtypes of CBD have been noted for clinical differences, but their pathogenic mechanisms are unclear.
METHODS: To elucidate the genetic basis of CBD, we performed lncRNA and mRNA sequencing and bioinformatic analysis on 18 cystic and 18 fusiform CBD samples.
RESULTS: We identified differentially expressed mRNAs and lncRNAs between the two types of CBD, and constructed coexpression modules that correlated with clinical characteristics of CBD using weighted gene coexpression network analysis. We found that the brown module was the highest positive correlation with fusiform CBD (R = 0.67, p = 7.9e-6) and contained the most genes. We then built a lncRNA-mRNA coexpression network to identify potential target genes of lncRNAs in CBD, and a protein-protein interaction network to investigate the hub genes from the target genes and the brown module. Finally, we performed enrichment analyses and found differences between cystic and fusiform CBD in hepatobiliary system development, liver and pancreas development involving hub genes ONECUT1 and HNF1B that could be regulated by corresponding lncRNAs.
CONCLUSIONS: Our study suggests that lncRNAs may modulate pancreaticobiliary duct development differently in cystic and fusiform CBD, providing new insights for etiology studies and clinical treatment.

OBJECTIVE: Preoperative comprehension of the anatomical variations of the hepatic artery and bile duct is essential for safe laparoscopic surgery for pancreaticobiliary maljunction (PBM). This study aimed to investigate the impact of anatomical variations of the hepatic artery and bile duct on surgical technique and postoperative complications.
METHODS: We conducted a retrospective review of patients with PBM who underwent laparoscopic surgery at our institution between January 2014 and December 2022 to investigate anatomical variations in the hepatic artery and bile duct, surgical technique, and postoperative complications.
RESULTS: We included 112 patients with PBM, with a median age of 4 years (interquartile range, 0-55). Overall, 29 of 112 patients had an aberrant right hepatic artery (ARHA) running ventral to the common hepatic duct (CHD), and they underwent hepaticojejunostomy on the ventral side of the ARHA. Additionally, eight of 112 patients had an aberrant posterior hepatic duct (APHD), which was joined to the CHD in all but one case. The presence of APHD was associated with postoperative bile leak occurrence.
CONCLUSIONS: Performing hepaticojejunostomy ventral to the ARHA is important to prevent complications. Furthermore, APHD may be a risk factor for postoperative bile leak and requires careful bile duct plasty.

Congenital biliary dilatation (CBD) is a congenital malformation of focal dilatation of the extrahepatic bile ducts, including the common bile duct, and is often associated with pancreaticobiliary maljunction (PBM). In this article, we report a CBD case that presented with focal dilation of the common bile duct without PBM (Todani\'s classification type Ib). The patient was a 32-year-old man who visited a doctor with a chief complaint of abdominal distension. Computed tomography revealed cystic dilatation of the common bile duct, and the patient was referred to our institution. Magnetic resonance cholangiopancreatography showed cystic dilatation of the common bile duct with a maximum diameter of 7 cm; however, evaluating the presence of PBM was challenging. Endoscopic ultrasonography showed small gallstones and debris in the dilated common bile duct and no thickening of the gallbladder wall. Endoscopic retrograde cholangiopancreatography revealed no PBM or markedly elevated bile amylase levels. Based on these findings, the patient was diagnosed with Todani Type Ib CBD. Since this patient did not have pancreatobiliary reflux, it was unclear whether the risk of developing biliary tract cancer was high, and since the treatment was highly invasive, the decision was to follow up without surgical treatment.

Choledochocele is defined as a congenital dilatation of the distal intramural part of the common bile duct protruding into the wall of the descending duodenum, typically without pancreaticobiliary maljunction. However, some cases present with a similar pathophysiology to pancreaticobiliary maljunction, including reciprocal reflux of pancreatic juices and bile, leading to protein plugs, pancreatitis, and biliary tract carcinogenesis. Choledochocele is relatively rare and its anatomy, physiology, pathology, and clinical features are thus not well known. We describe a patient with choledochocele who suffered from repeated severe acute pancreatitis and underwent subtotal stomach-preserving pancreatoduodenectomy, in whom the pathological findings of choledochocele showed hyperplasia.