Long‐Term Outcomes of Congenital Biliary Dilatation Surgery: A Single‐Center Study Highlighting the High Incidence of Complications Within 5 Years
Department of Pediatric Surgery Nagoya University Graduate School of Medicine Nagoya Japan
* Correspondence:Hiroo Uchida (uchida.hiroo.f5@f.mail.nagoya-u.ac.jp)
ABSTRACT
Background
Congenital biliary dilatation (CBD) is a rare anomaly often treated surgically, yet postoperative complications remain a concern. This study aimed to evaluate the incidence, timing, and risk factors of such complications after CBD surgery.
Methods
A retrospective review was conducted on 184 patients with CBD who underwent either open or laparoscopic surgery, with a mean follow‐up of 9 years. The analysis focused on postoperative complications, including bile duct–related issues, pancreatic complications, and bowel obstruction.
Results
Complications occurred in 14.7% of patients, predominantly bile duct–related (11.4%), followed by pancreatic (1.6%) and bowel obstruction (1.6%). Most bile duct complications, including anastomotic and intrahepatic strictures, emerged within 5 years postoperatively. Residual bile ducts were more common after open surgery, but no significant difference in other complications was observed between surgical approaches. No biliary malignancies developed during follow‐up.
Conclusion
The majority of complications occurred within 5 years after surgery, underscoring the importance of intensive monitoring during this period. Regular imaging and blood tests are essential for early detection. Although no malignancies were observed, long‐term follow‐up remains critical to address late‐onset risks.
Trial Registration: Clinical registration number: 2023‐045432262
Graphical
Maeda and colleagues retrospectively evaluated long‐term outcomes in 184 patients after surgery for congenital biliary dilatation. Most postoperative complications occurred within five years, but late‐onset complications also developed beyond this period. These findings highlight the need for sustained postoperative surveillance to enable early detection and prevention of severe biliary complications.
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Article notes
Footnote Group
1Introduction
Congenital biliary dilatation (CBD), also known as a choledochal cyst, is a rare congenital anomaly characterized by abnormal bile duct dilatation with pancreaticobiliary maljunction. While the correct surgical intervention, which typically involves cyst excision and biliary‐enteric anastomosis, has significantly improved patient outcomes, postoperative long‐term complications remain a major concern. Despite the technical advancements in surgical management, patients with CBD are still predisposed to various complications, some of which may present years after the initial surgery. These postoperative complications include recurrent cholangitis, hepatolithiasis, intrahepatic bile duct stenosis/anastomotic stricture, intrapancreatic residual bile duct stones/carcinoma, pancreatitis, and an increased risk of bile duct carcinoma.
Hepatolithiasis and repeated cholangitis are often caused by bile stasis due to bile duct stenosis and anastomotic stricture, and pancreatitis is caused by the residual intrapancreatic bile duct or pancreatic duct divisum. It has been reported that hepatolithiasis occurs in approximately 10% of CBD cases after surgery, especially in cases with preoperative intrahepatic bile duct dilatation, such as those with the Todani IVa Classification [1, 2, 3]. Specifically, in the case of hepatolithiasis, it has been demonstrated that hepaticoenterostomy can create an environment where intestinal bacteria directly mix with bile. The presence of bile stasis could lead to the formation of stones. The incidence of bile duct cancer after CBD surgery is an estimated 0.7%–5.4% [4, 5, 6, 7, 8], and this malignancy occurs at a younger age than it does in patients with normal bile duct structure, highlighting the instrumentality of postoperative follow‐up.
Long‐term follow‐up studies have revealed that complications such as hepatolithiasis and bile duct carcinoma can occur decades after surgery, raising important questions about the appropriate duration and methods of postoperative surveillance. Additionally, factors such as incomplete cyst excision, bile stasis, and anatomical variations of the bile and pancreatic ducts may contribute to the development of these complications, although the precise mechanisms are still under investigation. Given the potential severity of these complications, their long‐term impact on patient morbidity and mortality underscores the need for a comprehensive understanding of their time of onset, incidence, and risk factors.
With time, surgical techniques have evolved significantly, resulting in the performance of a wide array of surgical procedures, including laparoscopic and robotic surgery in the context of minimally invasive surgery, in addition to traditional open surgery. Although short‐term surgical outcomes have been reported, there is a paucity of literature on long‐term postoperative complications such as intrahepatic stones and cholangitis [9].
This study aimed to investigate the temporal patterns and nature of long‐term postoperative complications in patients with CBD. Specifically, we aimed to determine when various complications, such as hepatolithiasis, cholangitis, pancreatitis, and bile duct cancer, are most likely to occur and to identify potential predictors that could inform postsurgical monitoring protocols. The subsequent analysis will compare the two techniques, focusing on the incidence of long‐term complications and the relative merits of each approach. Understanding these patterns will enhance our ability to develop tailored follow‐up strategies, improving long‐term outcomes and potentially preventing life‐threatening sequelae in patients with CBD.
2Methods
This study was approved by the institutional review board (approval number: 2023‐045432262) and was performed per the ethical standards outlined in the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. A retrospective chart review was performed on patients who had undergone radical CBD surgery from August 2004 to December 2023. These patients had been regularly followed up at our institution postoperatively. The surgical procedures performed included extrahepatic bile duct resection with gallbladder removal and hepaticojejunostomy using the Roux‐en‐Y reconstruction technique via the retrocolic route in each case. From August 2004 to July 2013, open surgery was primarily performed. After August 2013, laparoscopic surgery became the standard approach. Importantly, both open and laparoscopic surgeries were conducted based on the same surgical principles and technical concepts, with no differences in the extent of resection or reconstruction method between the two approaches. Bile duct plasty was performed when intraoperative membranous stenosis or septal stenosis in the hilar bile duct was observed, typically confirmed by preoperative MRCP. The cut surface of the membranous or septal structure was then carefully sutured with 5–0 or 6–0 absorbable material to achieve hemostasis and minimize the risk of cicatricial stricture formation.
Baseline demographics and clinical data were collected, including patient age at the time of surgery, current age, sex, body weight, and the modified Todani classification. The focus of this study was the cause of readmissions related to postoperative complications specific to CBD surgery, including bile duct‐related complications, pancreatic‐related issues, bowel obstruction, and others. We also examined the timing of each complication in relation to the year postsurgery. At our institution, double‐balloon enteroscopic retrograde cholangiography (DBERC) is performed in the case of repeated cholangitis, cholangitis with bile duct dilatation, or hepatolithiasis. Patients who underwent DBERC were assessed for the presence of “bile duct stenosis” or “anastomotic strictures.” Bile duct strictures were diagnosed if the presence of bile duct mucosa between the stenotic and anastomotic regions was confirmed via endoscopy, while anastomotic strictures were diagnosed if the bile duct mucosa was absent in this area [10] (Figure 1A,B). At our institution, long‐term postoperative follow‐up protocols for patients are structured as follows: during the first five postoperative years, blood tests and abdominal ultrasound are conducted every 6 months, with magnetic resonance cholangiopancreatography (MRCP) performed every 2 years. After the initial five‐year period, annual blood tests and abdominal ultrasound examinations are continued, while MRCP is performed every 5 years. This follow‐up regimen is designed to monitor for potential long‐term complications, such as intrahepatic bile duct dilatation, hepatolithiasis, and other biliary or pancreatic issues, ensuring early detection and timely intervention. If abdominal symptoms or imaging tests suggest intrahepatic stones or intrahepatic bile duct dilatation, DBERC would be performed.
2.1Statistical Analysis
Continuous variables are presented with mean values with standard deviations or median values with interquartile ranges for normally distributed variables and variables with skewed data distributions, respectively. Comparisons between groups of continuous data were performed using Student's t‐test for normally distributed data or the Mann–Whitney U test for data with skewed distributions. Categorical data are presented as frequencies with percentages, and comparisons between groups of categorical data were performed with the Chi‐square test or Fisher's exact test.
All data analyses were performed using JMP Pro 13.0 (JMP, NC, USA), and p values of < 0.05 were considered statistically significant.
3Results
3.1Patient Characteristics
A total of 184 patients (83 open, 101 laparoscopic) whose postoperative course could be checked to data were analyzed. Table 1 shows patient background data and complication rates. The median ages of the patients during surgery and at present were 3 (1–6) years and 14 (9.3–20.0) years, respectively. The median weight and duration of postoperative follow‐up were 13.2 (9.6–20.0) kg and 9 (6–15) years, respectively. Of these, twenty‐seven patients (14.7%) were hospitalized due to complications related to CBD surgery. Complications involving the intrahepatic bile ducts and hepaticojejunostomy occurred in twenty‐one patients, pancreatic‐related complications in three patients, and bowel obstruction in three patients. No cases of cholangiocarcinoma were observed.
| Open surgery | Laparoscopic surgery | Total | p | |
|---|---|---|---|---|
| Number (n) | 83 | 101 | 184 | — |
| Age at surgery (years, IQR) | 3 (1–5) | 3 (1–8) | 3 (1–6) | 0.82 |
| Current age (years) | 18 (15–22) | 10 (7–13.5) | 14 (9.3–20) | < 0.01 a |
| Body weight at surgery (kg, IQR) | 13.8 (10–18.8) | 12.7 (9.3–23.3) | 13.2 (9.6–20.0) | 0.72 |
| Observation period (years, IQR) | 15 (13–17) | 6 (5–7) | 9 (6–15) | < 0.01 a |
| Patients were observed over more than 10 years (n) | 83 (100%) | 6 (5.9%) | 89 (48.4%) | < 0.01 a |
| Sex (M/F) (n) | 18/65 | 24/77 | 42/142 | 0.86 |
| Type of Todani Classification | 15/18/47/2/1 | 16/15/65/5/0 | 31/33/112/7/1 | 0.45 |
| (Ia/Ic/IVa/no dilatation/unknown) (n) | ||||
| Complication‐related hospitalization (n) | 7 (8.4%) | 20 (19.8%) | 27 (14.7%) | 0.04 a |
| Bile duct complication | 5 (6.0%) | 16 (15.8%) | 21 (11.4%) | 0.06 |
| Pancreas complication | 0 (0%) | 3 (3.0%) | 3 (1.6%) | 0.25 |
| Bowel obstruction | 2 (2.4%) | 1 (1.0%) | 3 (1.6%) | 0.45 |
| Bile duct cancer (n) | 0 (0%) | 0 (0%) | 0 (0%) | 1.00 |
3.4Bowel Obstruction
Three patients (two with OS and one with LS) underwent treatment for bowel obstruction (Table 4). They all required surgery; two of them were operated on for internal hernias, with ensuing LS and OS. All internal hernias occurred within 6 months postoperatively. There was a case of adhesive bowel obstruction, and surgical intervention was deemed necessary 8 years following the initial surgical procedure.
| Case | Age (years) | Body weight (kg) | Sex | Procedure | Diagnosis | Time of onset | Treatment | Follow‐up period (years) |
|---|---|---|---|---|---|---|---|---|
| 1 | 3 | 13 | F | OS | Internal hernia with band | 2 weeks | Band excision | 12 |
| 2 | 13 | 42.5 | F | LS | Petersen hernia | 6 months | Hernia repair | 8 |
| 3 | 3 | 12 | F | OS | Adhesion | 8 years | Dissection of adhesions | 20 |
3.5Postoperative Complications Categorized by Onset Timing
Postoperative complications were observed at different time points, and they can be categorized into three groups: within 1 year, within 5 years, and beyond 5 years after surgery.
Within the first postoperative year, an array of complications was observed. Internal hernia occurred in two cases within a year, while anastomotic stricture was observed in three cases. Intrahepatic bile duct stenosis was reported in two cases during this period. Additionally, pancreatitis developed in two cases within the first year, meaning that 100% of pancreatitis cases occurred within this timeframe.
Between 1 and 5 years postoperatively, all cases of “simple cholangitis” and one anastomotic stricture developed, respectively, and intrahepatic bile duct stenosis was observed in six cases. The protein plug at a common channel was removed using endoscopic retrograde cholangiopancreatography 2 years after the surgery, implying that 100% of “simple cholangitis” (5/5 cases), 80% of anastomotic stricture (4/5 cases), 80% of intrahepatic bile duct stenosis (8/10 cases), 100% of bile duct dysplasia (1/1), 100% of pancreas‐related complications (3/3 cases), and 66.7% of bowel obstruction (2/3 cases) cases occurred within the first 5 years after surgery.
Beyond the fifth postoperative year, anastomotic stricture occurred in one case 11 years after surgery, and intrahepatic bile duct stenosis was reported in two cases, one 10 years after surgery and the other 12 years after surgery. Additionally, adhesive small bowel obstruction was noted in one case 8 years postoperatively.
3.6Comparison of Postoperative Complications Between Laparoscopic and Open Surgery
Biliary complications, including “simple cholangitis,” occurred in 16 cases in the laparoscopic group and five cases in the open group; however, the difference between the two groups was not statistically significant (p = 0.06). Anastomotic stricture, with or without intrahepatic bile duct stenosis, was observed in four cases in the laparoscopic group and one case in the open group (p = 0.38), while isolated intrahepatic bile duct stenosis was observed in six cases in the laparoscopic group and four cases in the open group (p = 1.0), showing no statistically significant difference (Table 5). Intrapancreatic residual bile ducts were more common in cases involving open surgery (p < 0.01). However, for pancreatic‐related complications (p = 0.25) and bowel obstruction (p = 0.59), the surgical techniques did not differ significantly from each other.
| Variables | OS | LS | p |
|---|---|---|---|
| Number (n) | 83 | 101 | |
| Bile duct complication | 5 (6.0%) | 16 (15.8%) | 0.06 |
| Anastomosis stricture | 1 (1.2%) | 4 (4.0%) | 0.38 |
| Bile duct stenosis alone | 4 (4.8%) | 6 (6.0%) | 1.00 |
| Hepatolithiasis | 4 (4.8%) | 5 (5.0%) | 1.00 |
| Pancreatic complication | 0 (0%) | 3 (3.0%) | 0.25 |
| Residual intrapancreatic bile duct | 6 (7.7%) | 0 (0%) | < 0.01 a |
| Bowel obstruction | 2 (2.4%) | 1 (1.0%) | 0.59 |
4Discussion
This study aimed to assess the incidence and timing of complications following CBD surgery. Previous reports suggest that cholangitis occurs in 1.8 to 15% of cases postoperatively, often occurring 5–15 years after surgery [11, 12]. However, these findings are based on relatively small‐sample studies that have not extensively explored other complications like pancreatic issues and bowel obstructions.
In this study, bile duct–related complications were observed in approximately 10% of patients, with 85% of cases occurring within 5 years of surgery. Some of these cases were identified through magnetic resonance cholangiopancreatography (MRCP) during their asymptomatic phases, underscoring the importance of this imaging technique for early detection. Anastomotic strictures tend to become apparent relatively early after surgery, either through symptoms or imaging. Intrahepatic bile duct strictures also commonly present early postoperatively, with 80% of cases being detected within 5 years. Therefore, thorough and regular imaging should be performed within the first 5 years after surgery. Notably, as shown in Table 2, only one patient with hepatolithiasis had coexisting anastomotic and bile duct strictures, and this case was identified 11 years after surgery. In contrast, all other patients with hepatolithiasis did not have associated anastomotic strictures at the time of stone detection. This pattern may reflect our institutional practice of conducting frequent imaging with ultrasound and MRCP during the first five postoperative years, which likely enables early detection and endoscopic treatment of anastomotic strictures before stone formation occurs. In our practice, anastomotic strictures are promptly managed using DBERC‐guided balloon dilatation. We speculate that this approach prevents chronic bile stasis and thereby reduces the risk of hepatolithiasis. Moreover, hepatolithiasis appeared to be more strongly associated with localized intrahepatic bile duct stricture rather than early diffuse intrahepatic bile duct dilatation. In several cases, focal intrahepatic strictures were identified during DBERC despite being undetectable on routine MRCP. These findings suggest that hepatolithiasis may result from subtle intrahepatic bile flow impairment rather than generalized postoperative bile stasis, emphasizing the importance of careful long‐term imaging surveillance focused on intrahepatic architecture.
In our opinion, our postoperative surveillance protocol, which includes MRCP immediately after surgery, subsequent intervals (1, 3, 5, 7, and 10 years), and then every 5 years, as well as blood tests and ultrasound at least every 6 months within the first 5 years after surgery, is appropriate.
Intrahepatic stones were found in 4% of cases (8/184), which is lower than the commonly reported 10%. This reduced incidence might be due to proactive bile duct plasty performed during surgery, preventing bile stasis. Biliary‐related complications occur within 5 years postoperatively in 85% of cases. However, even after more than 10 years after surgery, the remaining 15% of patients still develop complications. Out of eighty‐nine patients who had been followed up for over 10 years, three patients (3.4%) developed complications. Therefore, careful long‐term postoperative follow‐up is necessary [13]. Based on our experience, when bile duct stenosis is suspected—such as by MRCP findings after recurrent cholangitis—our first‐line treatment is balloon dilatation under DBERC guidance. If endoscopic intervention proves ineffective, we consider percutaneous transhepatic biliary drainage (PTBD) or surgical resection, including hepatectomy, depending on the location and extent of the stricture.
Pancreatic complications, including two cases of pancreatitis, were observed shortly after postoperatively. Pancreatic divisum was the main cause in these cases, and no pancreatitis due to residual intrapancreatic bile ducts was found. This might be attributed to the surgical approach employed at our institution, where extensive bile duct resection minimizes the risk of residual ducts and associated complications. In recurrent pancreatitis cases, comprehensive testing (e.g., ERP) should be considered to evaluate potential pancreatic duct abnormalities.
For bowel obstructions, three patients required surgical intervention. Most cases, including internal hernias, were identified within the first 6 months post‐surgery, indicating the need for careful monitoring during this period. Despite the anticipated higher prevalence of bowel obstruction in the open surgery group, the techniques did not differ significantly from each other. Nevertheless, the incidence of at least two readmissions for bowel obstruction was found to be higher in the open surgery group.
There was no significant difference in the prevalence of bile duct–related complications such as cholangitis, anastomotic stenosis, and intrahepatic bile duct stricture between laparoscopic surgery and open surgery. However, studies of the laparoscopic surgery group showed that bile duct–related complications tended to occur within 5 years after surgery. This may suggest that laparoscopic biliary‐enteric anastomosis is associated with a higher risk of transient complications. As a result, it is imperative to pay close attention to the biliary‐enteric anastomosis in laparoscopic surgery. In our cohort, we examined the anastomotic diameter in LS cases that developed strictures and found it was approximately 11.5 mm. Interestingly, even when the anastomotic diameter was similarly small, strictures developed in some cases but not in others, and no definitive differentiating factor could be identified. For OS cases, it was not feasible to retrospectively assess the anastomotic diameter; however, the incidence of strictures appeared to be lower than in LS, although this difference was not statistically significant. This may suggest that technical aspects unique to laparoscopic anastomosis—such as limited tactile feedback or reliance on magnified vision—could contribute to the development of strictures. Nevertheless, the exact mechanism remains unclear and warrants further investigation. Furthermore, analyses revealed that residual intrapancreatic bile ducts were more common in open surgery. This finding may suggest that laparoscopic surgery provides a superior operative field during intrapancreatic bile duct dissection, facilitating more comprehensive dissection and resection. Since the observation period for laparoscopic surgery is shorter than that for open surgery, a longer observation period for laparoscopic cases may provide a clearer understanding of postoperative outcomes.
Although there were no cases of malignancy in our cohort, previous studies report that 0.7%–5.4% of patients with a history of CBD surgery develop biliary tract malignancies, such as cholangiocarcinoma.
These malignancies often present at a younger age than those occurring in individuals with normal bile ducts, emphasizing the importance of long‐term surveillance. Notably, the risk of malignancy is higher in patients with incomplete cyst excision, bile stasis, or anatomical variations in the bile and pancreatic ducts, highlighting the need for careful, ongoing monitoring even in asymptomatic patients. Periodic imaging, such as MRCP, along with blood tests and ultrasonography, should be maintained over long periods to detect potential malignant transformation early, ensuring timely intervention and improving patient outcomes.
This study provides information regarding the long‐term outcomes of CBD surgery based on a relatively large retrospective cohort of 184 cases. However, several limitations should be acknowledged.
First, as a single‐center retrospective study, the findings may not be generalizable to other institutions, where differences in surgical techniques, follow‐up protocols, and patient demographics could affect outcomes. A multicenter study would provide a more comprehensive understanding of long‐term complications. Second, in this study, there was an imbalance in the follow‐up period between surgical approaches. The follow‐up duration for open surgery cases is longer than that for laparoscopic cases, making it challenging to directly compare long‐term outcomes between the two surgical techniques. This could lead to an underestimation of the incidence of late‐onset complications in the laparoscopic group, potentially skewing the assessment of its long‐term safety and efficacy. Third, the study reports no cases of biliary malignancy during the follow‐up period, whereas previous studies have documented a 0.7%–5.4% incidence of cholangiocarcinoma after CBD surgery. Since biliary malignancies may develop decades after surgery, the current follow‐up period may be insufficient to capture the true risk. Longer follow‐up periods are necessary to accurately assess the oncological safety of CBD surgery.
Despite these limitations, this study provides valuable data on the incidence and timing of complications after CBD surgery. Future research should involve multicenter collaborations and longer follow‐up periods to ensure a more accurate evaluation of long‐term outcomes.
5Conclusion
The majority of complications occur within the first 5 years after CBD surgery, necessitating frequent follow‐up during this period. However, given the potential for developing hepatolithiasis and bile duct stenosis beyond the first five postoperative years, regular follow‐up with imaging is crucial even after this initial period. For patients without symptoms during the first 5 years after surgery, annual follow‐up may suffice. Long‐term vigilance is essential to detect potential bile duct cancer and ensure timely intervention.
Ethics Statement
This study was approved by the institutional review board (approval number: 2023‐045432262) and was performed per the ethical standards outlined in the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.
Conflicts of Interest
The authors declare no conflicts of interest.
Acknowledgments
The authors have nothing to report.
Data Availability Statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.