|Year : 2021 | Volume
| Issue : 6 | Page : 226-233
Clinical presentation and outcome of pediatric congenital biliary dilatation: A study based on pancreaticobiliary maljunction
Sheng-Yang Huang1, Chou-Ming Yeh2, Chia-Man Chou1, Hou-Chuan Chen3
1 Department of Surgery, Taichung Veterans General Hospital, Taichung; Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
2 Department of Surgery, Taichung Hospital, Ministry of Health and Welfare, Executive Yuan; Department of Healthcare, Central Taiwan University of Science and Technology, Taichung, Taiwan
3 Department of Surgery, Taichung Veterans General Hospital, Taichung, Taiwan
|Date of Submission||02-Sep-2021|
|Date of Decision||23-Sep-2021|
|Date of Acceptance||02-Nov-2021|
|Date of Web Publication||30-Nov-2021|
Department of Surgery, Taichung Veterans General Hospital, National Yang Ming Chiao Tung University, No. 1650, Sec. 4, Taiwan Boulevard, Taichung 40705
Source of Support: None, Conflict of Interest: None
Background: The commonly used anatomical classification of congenital biliary dilatation by Todani is not directly related to types of pancreaticobiliary maljunction (PBM). This work is to investigate clinical presentation and surgical outcomes according to PBM classification proposed by the Japanese Study Group on Pancreaticobiliary Maljunction. Pancreaticobiliary junction angle, common channel length, and diameter of dilatation are studied as well.
Materials and Methods: Patients of redo operation, without preoperative images, and lacking clearly documented outcomes were excluded. After exclusion, 79 patients who underwent Roux-en-Y hepaticojejunostomy between January 1994 and December 2019 were enrolled for this retrospective study. Medical records were reviewed, and perioperative parameters were collected. Todani's classification, PBM types, pancreaticobiliary junction angle, common channel length, and dilatation diameter were determined based on magnetic resonance cholangiopancreatography or computed tomography. Clinical presentation and outcome were compared between groups of different anatomical features.
Results: PBM type A (stenotic), type B (nonstenotic), and type C (dilated channel) consisted of 48 (60.8%), 18 (22.8%), and 11 (13.9%) patients, respectively; and two patients (2.5%) had no PBM. Patients of PBM type A were younger and had more Todani's type Ia lesion. Patients of PBM type B and C had either Todani's type Ia or Ic lesion, but type IVa had only PBM type B. Longer common channel (1.27 vs. 0.81 cm, P < 0.001) and wider dilatation (4 vs. 2 cm, P < 0.001) were found in patients with right pancreaticobiliary angle (90°). Clinical outcome was similar in different Todani's types, PBM types, and pancreaticobiliary angle. Serum alkaline phosphatase level higher than 675 U/L was associated with major perioperative complications. Preoperative jaundice, mass, and dilatation wider than 5 cm were related to subsequent liver cirrhosis.
Conclusion: PBM types and pancreaticobiliary junction groups are feasible for surgical planning, but not related directly to outcome. Palpable abdominal mass suggests higher risk of perioperative and late complications. For subsequent liver cirrhosis, laboratory data of disease onset and dilatation diameter wider than 5 cm are important risk factors.
Keywords: Congenital biliary dilatation, pancreaticobiliary junction angle, pancreaticobiliary maljunction
|How to cite this article:|
Huang SY, Yeh CM, Chou CM, Chen HC. Clinical presentation and outcome of pediatric congenital biliary dilatation: A study based on pancreaticobiliary maljunction. Formos J Surg 2021;54:226-33
|How to cite this URL:|
Huang SY, Yeh CM, Chou CM, Chen HC. Clinical presentation and outcome of pediatric congenital biliary dilatation: A study based on pancreaticobiliary maljunction. Formos J Surg [serial online] 2021 [cited 2022 Jun 29];54:226-33. Available from: https://www.e-fjs.org/text.asp?2021/54/6/226/331637
| Introduction|| |
Pediatric congenital biliary dilatation is a disease commonly named as “choledochal cyst” and was initially classified by Alonso-Lej. After the introduction of revised anatomical classification by Todani in 1977, the spectrum of this disease had further broadened widely to fit all variations of lesions involving extrahepatic with or without intrahepatic bile ducts. Some authors created additional types other than original Todani's classification, such as type Id and type VI.,, However, there is no consensus on clear definition of additional types and most patients can be categorized into classical anatomical types. Surgical approaches can be planned individually according to different types.,, Incidence of congenital biliary dilatation is much higher in the Asian population, about 1 in 1,000 in Japan and Taiwan., The true etiology of the disease is still under investigation and most experimental models fail to explain the whole picture., Todani's classification used for surgical planning is associated with but not directly related to pancreaticobiliary maljunction (PBM), pancreaticobiliary junction angle, and length of common channel. Therefore, some authors have published different classifications of associated PBM types,, but the description is complicated and had have not been widely used by others. In 2015, a simple and comprehensive PBM classification has been was proposed by the Japanese Study Group on Pancreaticobiliary Maljunction (JSGPM), and the relationship between four types of PBM and clinical presentation has been confirmed in the literature.,
This work is to investigate the patient characteristics, clinical symptoms, inflamed organs, biliary stones, bile amylase levels, perioperative complications, and surgical outcomes according to Todani's types, PBM types, pancreaticobiliary junction angle, common channel length, and diameter of dilatation. The relationship of Todani's classification and PBM types based on the current patient group is established.
| Materials and Methods|| |
From January 1994 to December 2019, total of 108 patients who were 18 years old or younger underwent excision and Roux-en-Y hepaticojejunostomy in our institute for congenital biliary dilatation, regardless of open or laparoscopic approach. Medical records were reviewed, and perioperative parameters were retrospectively collected. Age and body weight were recorded on the day of surgery. Jaundice was defined as serum total bilirubin level higher than 2 mg/dL. Cholangitis, pancreatitis, and hepatitis were diagnosed mainly according to related blood test results. Todani's classification and PBM types were determined based on preoperative magnetic resonance cholangiopancreatography (MRCP) or computed tomography (CT). All recognized types of PBM in all patients were as follows: (a) stenotic type, (b) nonstenotic type, and (c) dilated channel type, whereas complex type D was not noted in this series. Pancreaticobiliary junction angle was defined as the angle between distal common bile duct and pancreatic duct. The angle was measured and categorized into right angle (≥90° angle) and sharp angle (<90° angle). Common channel length and diameter of the lesion at the widest region of dilatation were measured. Examples of preoperative images used to determine anatomical features are shown in [Figure 1]. Choledochal bile was obtained during operation for amylase test and culture. Patients received redo operation, without reliable preoperative images, and lacking clearly documented outcomes were excluded from the current analysis. Complications were graded by the Clavien–Dindo classification., Hospital stay was defined as days in hospital after surgery. Clinical presentations and outcomes were compared by statistical method.
|Figure 1: Examples of MRCP images used to determine anatomical features: (a) Todani type Ia, PBM type A, right angle; (b) Todani type Ic, PBM type B, right angle; (c) Todani type type Ic, PBM type C, sharp angle; (d) Todani type IVa, PBM type A, right angle. Yellow lines between arrowheads represent distance of common channel|
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This study was approved by the Institutional Review Board of Taichung Veterans General Hospital, Taichung, Taiwan (TCVGH-IRB No. CE20213B). Statistical analysis was accomplished by the Kruskal–Wallis test and the Mann–Whitney U-test for the continuous data, and χ2 test and Fisher's exact test for categorical data. Univariate odd ratio analysis for major and long-term complications were performed to discover risk factors and receiver operating characteristic (ROC) curve studies of preoperative quantitative variables for predicting complications. Area under curve (AUC) larger than 0.7 with significant P value revealed acceptable discrimination, and the cutoff level was measured using Youden index. MedCalc Statistical Software version 19.2.0 (MedCalc Software bv, Ostend, Belgium) was used for statistical analysis, and P < 0.05 was considered statistically significant for comparison (a = 0.05, two-tailed).
| Results|| |
MRCP or CT was not routinely performed for patients with suspected biliary dilatation in our institute before 1999, and the diagnosis was made according to TC-99 m diisopropyl iminodiacetic acid (DISIDA) scan and hepatobiliary sonography. A total of 29 patients without clear preoperative MRCP or CT images were excluded. After exclusion, 79 patients (42 open; 37 laparoscopies) were enrolled for further study. Among them, 2 (2.5%) patients had normal pancreaticobiliary junction; whereas, 48 (60.8%), 18 (22.8%), and 11 (13.9%) patients had PBM type A, type B, and type C, respectively. Todani type Ia, Ic, and IVa were noted in 42 (53.2%), 28 (35.4%), and 7 (8.9%) patients. The demographic and anatomical characteristics are listed in [Table 1]. No statistical difference of gender and bodyweight distribution was observed in PBM types. Patients of PBM type A were younger and had more Todani's type Ia lesion. Follow-up period was longer in PBM type C. Todani's type IVa was only noted in PBM type A (14.6% and 8.9% overall). Patients of PBM types B and C had either Todani's type Ia or Ic lesion. The longest common channel was observed in PBM type A (1.25 cm), and the widest dilatation in PBM type B (6 cm). Patients with right pancreaticobiliary junction angle (90° angle) underwent operation at younger ages and were lighter in weight. Right angle results more in Todani's type Ia lesions (73.3%) and sharp angle more in type Ic (70.6%). All Todani's type IVa patients were related to right angle. Longer common channels (1.27 vs. 0.81 cm) and wider dilatation (4 vs. 2 cm) were found in right-angle patients.
|Table 1: Demographic and anatomical features by different PBM types and pancreaticobiliary angle groups|
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[Table 2] shows the clinical presentation, laboratory data, and outcome of different Todani's classifications. Antenatal diagnosis was made only in 6 patients (7.8%), which were type Ia or IVa. Most patients presented abdominal pain, especially type Ic (96.4%, P < 0.001). Incidence of jaundice was higher in type Ia (38.1%) without statistical significance. Abdominal mass was found in only 7 patients (9.1% overall). Small proportion (n = 13, 16.9% overall) of patients fulfilled two of three classical symptoms, and nonsignificantly higher percentage was observed in type IVa (42.9%). No patients met full triad in this series. Asymptomatic patients were found only in type Ia and IVa. Cholangitis, pancreatitis, and hepatitis occurred more frequently in type Ic with no significant difference. Bile amylase level, bile culture, hospital stay, and complications were not different.
|Table 2: Clinical presentation, laboratory data, and outcome by Todani's classification|
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[Table 3] shows the clinical presentation and outcome of different PBM types. Only type A and B could be noted by sonography before birth. Abdominal pain was found more in type C, but no difference was found in other symptoms or asymptomatic presentation. Type C appeared to be related to higher incidence of cholangitis, pancreatitis, and hepatitis; however, the significance of the difference between the types was low. Amylase level of choledochal bile was insignificantly higher in type B, and positive culture was only observed in three patients. Overall complication rates were similar in all types.
|Table 3: Clinical presentation, laboratory data, and outcome by pancreaticobiliary maljunction types|
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The patients were further divided into two groups according to the pancreaticobiliary junction angle: 90° angle and <90° angle, as shown in [Table 4]. Most antenatally diagnosed patients had angle of 90°. Abdominal pain was significantly prevalent in the <90° angle group and abdominal mass more prevalent in the 90° angle group. Incidence of cholangitis or hepatitis was not different, and pancreatitis seemed to be more frequent in the <90° angle group. Absolute difference of median level was 2841 U/L, but no significance was observed. Hospital stay did not differ from each other in the two groups. Complication rate was not different in the two groups.
|Table 4: Clinical presentation, laboratory data, and outcome by pancreaticobiliary junction angle|
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Odds ratio calculation of categorical variants was conducted to identify risk factors of major perioperative complications (Grade III), blood transfusion requirement, subsequent liver cirrhosis, and recurrent postoperative cholangitis. The results are listed in [Table 5] and [Table 6]. No significant factors for major complication, transfusion, and recurrent cholangitis were identified. Only preoperative jaundice and mass were associated with subsequent liver cirrhosis. Therefore, multivariate logistic regression analysis was not further performed.
|Table 5: Univariate odds ratio for Grade III complication, transfusion, liver cirrhosis, and recurrent cholangitis|
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|Table 6: Results of receiver operating characteristic curve analysis predicting major and late complications (only significant predictors are presented)|
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Common channel length was supposed to be related to the width of dilatation for increased pressure in the affected bile ducts. Spot plot of common channel length and dilatation diameter disclosed weak relationship with low correlation coefficient (r = 0.385, P < 0.001) as shown in [Figure 2]. The two anatomical factors should be considered separately in further analysis. ROC curve analysis was conducted to search for critical value of preoperative laboratory data and images to predict clinical presentation and complications. ROC curves with AUC under 0.7 or P > 0.05 were not further demonstrated. [Figure 3] revealed ROC curves of common channel length and dilatation diameter using abdominal mass as clinical presentation.
|Figure 2: Scatter plot with local regression smoothing trendline capturing the relationship between common channel length and the maximal diameter of dilated bile ducts. The degree of smoothing is 80%|
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|Figure 3: (a) Receiver operating characteristic curve analysis of common channel length for predicting palpable mass. (b) Receiver operating characteristic curve analysis of dilatation diameter for predicting palpable mass. Criterion by Youden index is shown|
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The ROC curve analysis of preoperative quantitative variables for Grade III complication and liver cirrhosis found some significant predictors, as listed in [Table 7]. A serum alkaline phosphatase level of higher than 675 U/L was associated with higher incidence of major perioperative complications. High serum alkaline phosphatase, alanine aminotransferase, γ-glutamyl transpeptidase, total bilirubin, and low blood platelet count were related to liver cirrhosis. Dilatation diameter larger than 5 cm also posted threat to subsequent liver cirrhosis. For predicting major complications and liver cirrhosis, laboratory data in the acute phase seems to be more important than other factors.
|Table 7: Results of ROC curve analysis predicting major and late complications (only significant predictors presented)|
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| Discussion|| |
Congenital biliary dilatation is highly related to PBM according to studies of possible etiology.,,,, Although some other studies have demonstrated relatable genes to such disease, the current theory of PBM is suitable for anatomical study and clinical application. The true incidence of PBM is not officially reported worldwide. According to a national survey of endoscopic retrograde cholangiopancreatography results in South Korea, incidences of congenital biliary dilatation and PBM are 0.32% and 4.1%, respectively. Most patients with congenital biliary dilatation have PBM according to literature,,,, and the incidence in this study is 97.5%. PBM type A is the most frequent, which is 60.8% of in our series, 65% in an earlier Japanese report, and 41.3% in a later report. PBM type A patients in this study are significant younger, had more Todani's Type Ia lesion, longer common channel length, and wider biliary dilation, which are similar with the JSGPM report.
Furthermore, this study simplified the anatomical feature by pancreaticobiliary junctional angle. The 90° angle presented in 57% of patients and resulted in early diagnosis (21 months versus 47 months, P = 0.033). The observation differs from the report by Lipsett et al., in which 90° angle was found more frequently in elder patients, and the overall incidence of 90° angle is was close to the pediatric report by Miyano et al.(51.7%). The 90° group correlated well with Todani's classification in this study. The 90° favored type Ia lesion (73.3%), but the <90° was more likely to result in type Ic lesion (70.6%, P < 0.001). Type IVa was found in the right angle group exclusively. Common channel length and diameter of maximal dilatation were significantly different in two angle groups as seen in the literature., Patients with 90° angle presented longer common channel (1.27 cm versus 0.81 cm, P < 0.001), and the length of difference fitted the criterion of long common channel by Lipsett et al., which by definition was 10 mm or more.
None of the patients presented full classical clinical triad of abdominal pain, jaundice, and palpable right upper abdominal mass. Although earlier publications revealed incidence of classical triad up to 14%–17%,, the rarity of the current study was closer to the findings in the more recent literatures.,, For Todani's type Ia lesion, abdominal pain and jaundice were almost equally frequent. Abdominal pain was the cardinal symptom for type Ic lesion (96.4%). Incidence of pancreatitis was high in pediatric patient group, 23% according to Lipsett et al.,,, and related to type Ic lesion in this study. Hepatitis was also frequently noted in this study (51.9%). Thus, MRCP should be performed for every patient presenting with pancreatitis. Moreover, sonography for any hepatitis patient could increase the alarm of any possible biliary dilatation.
Abdominal pain was the most prevalent symptom of all PBM types,, and abdominal mass was limited to PBM type A. ROC curve of common channel length and diameter of maximal dilated lesion for mass presentation revealed the palpable lesion size that may be found during physical examination. Dilation up to 3.5 cm wide was easier to be detected before image study, and common channel length over 1.57 cm was related to abdominal mass. Pediatric patients, especially infants, were known to have more frequent palpable mass of congenital biliary dilatation.,, In this study, the mean age of patients with and without mass was 37.3 months and 47.0 months, respectively (P = 0.611). Like other two studies,, no significant difference of age was revealed regarding abdominal mass. Early and popular abdominal sonography before detailed physical examination in current medical practice might have caused the change. Cholangitis was common in all PBM types. Like in the literature,, incidence of pancreatitis was lower in type A (27.1%) than in type B (44.4%) and type C (54.5%), but the difference was not significant. As for hospital stay and perioperative complications, no difference was found between PBM types.
PBM type is highly related to Todani's classification, with type A for Todani's Ia and type C for Todani's Ic lesion, respectively. The association is clearly due to description of Todani, which Ia indicated a narrow distal common bile duct and Ic showed diffuse or cylindrical dilatation. Similar observation is also noted in the literature., Only seven patients have IVa lesion, and all their PBM are classified into stenotic type. The result suggests a crucial role of distal obstruction causing general dilatation of intrahepatic and extrahepatic bile ducts. Pancreaticobiliary junction angle is supposed to correspond to Babbit's proposed model. However, not every patient presented the same anatomical feature and was classified into sharp angles. This observation questions the etiology of this disease entity.,, By JSGPM definition, PBM type A does not necessarily but mostly means right pancreaticobiliary angle. On the other hand, PBM is not mandatory but is found in almost every case of congenital biliary dilatation in this study. Patients with or without PBM can be easily classified into two groups of 90° and <90° angle.
To look for risks factors of major (Grade III) perioperative complication (5 patients, 6.3%), blood transfusion requirement (5, 6.3%), subsequent liver cirrhosis (7, 8.9%), and recurrent cholangitis (6, 7.6%) after primary operation, risk ratio, and odds ratio analysis for univariate risks factors were performed. No difference of complication rate between age groups was noted in some reports,,, whereas others stated higher rates in older patients., Some authors suggested preventing surgery in neonates or small infants., In this study, age and body weight during surgery did not influence early or late complications. Categorical variables such as laparoscopic approach, Todani's type, PMB type, or 90° pancreaticobiliary angle also had low impact on adverse outcomes. Preoperative clinical presentation of jaundice and mass lesion was important in predicting subsequent liver cirrhosis. Patients presented with mass also had higher odds ratio for perioperative complication and recurrent cholangitis. Multivariate logistic regression analysis was not performed, for only a few risk factors were identified by odds ratio. Population size and low rate of complications were the major reasons.
The limitations of this study are its retrospective nature and small patient number. Some patients were excluded because the diagnosis was based on sonography, and DISIDA scans or images were missed.
| Conclusion|| |
PBM classification from JSGPM and pancreaticobiliary junction group is feasible and convenient for surgical planning. However, the clinical outcome is not always related to anatomical features. Small patient size or laparoscopic approach does not influence prognosis. Palpable abdominal mass suggests higher risk of perioperative and late complications. For subsequent liver cirrhosis, initial laboratory data and the diameter of the dilated common bile duct are important.
Financial support and sponsorship
Taichung Veterans General Hospital (Project No. TCVGH-1095401B and TCVGH-1095402C).
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]