Standardized Diagnosis and Treatment of Pancreaticobiliary Maljunction

Summary

Pancreaticobiliary maljunction predisposes to recurrent pancreatitis, pancreatobiliary stones, and biliary tract tumors. This article aims to enhance clinical recognition to facilitate early diagnosis and standardized management of this condition.

Abstract

According to extensive case analyses compiled by the Japanese Study Group on Pancreaticobiliary Maljunction (JSPBM), patients with Pancreaticobiliary Maljunction (PBM) exhibit a significantly elevated incidence of biliary tract tumors, ranging from 34% to 39%. This rate is dramatically higher than the population-based incidence of biliary tract tumors in the general population (approximately 0.002%). Beyond malignancy, PBM is associated with multiple common pancreatobiliary disorders, including recurrent pancreatitis, stones within the common pancreatobiliary channel, and pancreatic duct stones, which substantially impair patients' quality of life. Despite its insidious nature and frequent delayed or missed diagnosis, key clinical features such as recurrent pancreatitis, acalculous cholecystitis, and extrahepatic bile duct dilation provide crucial diagnostic clues. Standard diagnostic modalities include abdominal ultrasound, computed tomography (CT), and magnetic resonance cholangiopancreatography (MRCP). Endoscopic retrograde cholangiopancreatography (ERCP) serves as the definitive diagnostic and classification tool. Upon confirmation of diagnosis, patients should undergo curative surgery to mitigate the risk of biliary tract carcinogenesis. This article provides a detailed protocol for the diagnostic and therapeutic approaches to PBM.

Introduction

Pancreaticobiliary maljunction (PBM) was first reported by Japanese scholars Kozumi K and Kodama T in 1916. However, it was not until 1969 when Babbitt D P proposed an etiological explanation for congenital biliary dilatation and highlighted the correlation between PBM and biliary dilatation that the medical community began to recognize its significance¹.

In 1990, the Japanese Study Group on Pancreaticobiliary Maljunction (JSPBM) established diagnostic criteria for PBM, with the defining feature being the union of pancreatic and biliary ducts outside the duodenal wall. JSPBM has maintained an annual registry of PBM cases, publishing comprehensive analyses in 2003 and 2013^2,3. These studies revealed alarmingly high rates of biliary tract malignancies in PBM patients, 34.7% and 39.4% respectively, starkly contrasting with the general population incidence of 0.002%⁴.

Beyond its oncogenic potential, PBM is associated with multiple clinically significant complications, such as recurrent pancreatitis, protein embolus or calculi in the pancreatic duct, Biliary stones, or common channel concretions⁵. These complications severely affect patients' quality of life.

Therefore, the diagnosis and treatment of PBM represent a critical issue that hepatobiliary surgery urgently needs to address. Unfortunately, this condition remains underrecognized in China's medical community.

The diagnosis of PBM relies on Ultrasound, CT, and MRCP examinations, with ERCP serving as the definitive diagnostic method⁶. For confirmed cases with biliary dilatation, the currently recommended treatment approach is: cholecystectomy, Complete resection of extrahepatic bile ducts (from the hepatic duct confluence to the pancreaticobiliary junction), and hepaticojejunostomy reconstruction⁷.

It is recommended that the pancreatic bile duct be resected just above the pancreatic duct junction, leaving as little as possible, according to Japanese clinical practice guidelines for congenital biliary dilatation⁸. However, achieving this goal faces practical difficulties. This article presents a detailed demonstration of PBM diagnosis and definitive treatment approaches through a representative case. while showcasing the significant advantages of an endoscopic-surgical collaborative approach. By enabling direct bile aspiration for amylase measurement, facilitating the quantification of the common channel length, and allowing for the placement of a pancreatic stent to mark the pancreatobiliary junction and protect the pancreatic duct, ERCP offers significant advantages in the combined endoscopic-laparoscopic management of PBM.

Protocol

This protocol was approved by the Ethics Committee of Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, and written informed consent was obtained from the patient who underwent surgery.

1. Diagnostic methods

1. Magnetic Resonance Cholangiopancreatography (MRCP): MRCP serves as a reliable modality for determining the length of the pancreaticobiliary common channel in the diagnosis of PBM. Ensure the imaging protocol includes half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences, obtained using thin-slice coronal and axial T2-weighted parameters (repetition time: 1200 ms; echo time: 80 ms; slice thickness: 4 mm). Additionally, acquire thick-slab oblique projections along the trajectories of the common bile duct and pancreatic duct, with a repetition time of 4500 ms, echo time of 950 ms, and slice thickness of 60 mm. This combination of sequences enables high-resolution, multiplanar, and multi-angle three-dimensional visualization of the biliary and pancreatic systems, thereby offering clear delineation of the pancreaticobiliary junction.
2. Endoscopic Retrograde Cholangiopancreatography (ERCP): Perform pancreatobiliary ductography to confirm aberrant junction morphology, measure common channel length, identify anomalous confluence point, and classify PBM subtype.
3. To comprehensively remove the stones, employ standard ERCP techniques, including balloon sweeping and/or basket extraction under fluoroscopic guidance. Following confirmed stone clearance, systematically collect bile samples from the common bile duct using an aspiration catheter. Transfer each sample, with a volume of approximately 2-3 mL, to the laboratory for biochemical analysis. Measure amylase concentration using an automated enzymatic assay to quantitatively evaluate the presence of pancreatobiliary reflux.
4. Pancreatic duct stenting via ERCP
   1. Place a prophylactic pancreatic duct stent (5 French, 7 centimeter) preoperatively to serve as an intraoperative landmark and prevent iatrogenic pancreatic duct injury.The operation process follows the standard procedures of ERCP.
      NOTE: Prophylactic pancreatic duct stenting is not a routine procedure but may be considered in patients at high risk for post-ERCP pancreatitis.

2. Surgical procedure

NOTE: Definitive surgery is indicated for all confirmed PBM cases.

1. Laparoscopic port placement
   1. Establish standard 5-port configuration for laparoscopic access (umbilical, epigastric, right/left subcostal). The surgical method is based on previous reports⁹.
2. Cholecystectomy
   1. Perform prophylactic laparoscopic cholecystectomy⁹.
3. Extrahepatic bile duct mobilization
   1. Dissect the common bile duct (CBD) from surrounding tissues. Transect the common bile duct just below the confluence of the right and left hepatic ducts in a cephalad direction to ensure complete resection of the extrahepatic bile duct. Caudally, divide the duct immediately above the pancreaticobiliary junction, with careful dissection to minimize residual biliary tissue while avoiding injury to the pancreatic duct.
4. Choledochotomy and ductal exploration
   1. Incise the CBD approximately 5 mm at the cystic duct insertion site.
   2. Insert a choledochoscope to inspect biliary mucosa for metaplasia/dysplasia, advance to the distal CBD until visualizing the pancreatic duct orifice (identified by preplaced stent), and measure the distance to the junction using a calibrated probe.
5. Distal CBD transection
   1. Apply a non-absorbable polymer clip immediately proximal to the pancreaticobiliary junction. Transect the CBD above the clip.
6. Proximal CBD transection
   1. Divide the CBD at the hepatic duct confluence.
7. Hepaticojejunostomy
   1. Perform the Roux-en-Y hepaticojejunostomy using a 45 cm Roux limb. Create an end-to-side anastomosis between the hepatic duct and the jejunum. Use a linear stapler for the construction of the jejunojejunostomy. Complete the hepaticojejunal anastomosis using a single-layer continuous suturing technique with 5-0 absorbable suture. Meticulously spatialize the duct and anastomose it to the jejunum in a tension-free manner to minimize the risk of anastomotic stricture. Place a closed-suction drain adjacent to the anastomosis prior to abdominal closure.
8. Drain placement
   1. Position a closed-suction drain subhepatically.
9. Specimen handling
   1. Submit the resected CBD and gallbladder for histopathological examination.
10. Closure
    1. Close port sites in layers.Fascial layers at port sites 10 mm were routinely closed using figure-of-eight or simple interrupted sutures with absorbable suture material. Subcutaneous layers were approximated with interrupted absorbable sutures, and the skin was closed with subcuticular sutures. Confirm hemostasis at each layer prior to closure.

3. Postoperative management

1. Transfer all patients to the post-anesthesia care unit (PACU) for immediate recovery following surgery. Ensure the standard monitoring includes continuous electrocardiography, pulse oximetry, and non-invasive blood pressure measurements every 15 min until stable. Administer intravenous analgesia according to an institutional protocol, typically involving patient-controlled analgesia (PCA) with opioids or a multimodal regimen combining non-steroidal anti-inflammatory drugs and acetaminophen.
   1. Initiate oral intake gradually: Start clear liquids on postoperative day (POD) 1 after confirmation of bowel sounds and advance to a soft diet as tolerated. Monitor the abdominal drain for volume and character of output; remove it if output is serosanguinous and less than 30 mL per 24 h period. Check laboratory tests, including complete blood count and C-reactive protein levels on POD 1 and 3, or as clinically indicated.
   2. Continue Prophylactic intravenous antibiotics for 24 h postoperatively. Administer thromboprophylaxis with low molecular weight heparin until discharge. Discharge criteria included: adequate pain control with oral analgesics, tolerance of oral diet, absence of fever or signs of infection, and independent ambulation.

Results

The key outcomes in standardized diagnosis and treatment of PBM are as follows:

Definitive diagnosis of suspected cases
Magnetic resonance cholangiopancreatography (MRCP) revealed an anomalous pancreaticobiliary junction, dilated extrahepatic bile ducts, and suspected filling defects in the common bile duct (Figure 1). Endoscopic retrograde cholangiopancreatography (ERCP) was critical for confirmation (Figure 2). ...

Discussion

Pancreaticobiliary maljunction (PBM) is a congenital anomaly characterized by an abnormal connection between the pancreatic and biliary ducts beyond the duodenal wall, often leading to serious complications such as recurrent pancreatitis and biliary cancer. This study demonstrates a standardized protocol that integrates endoscopic and surgical techniques to enhance diagnostic accuracy and therapeutic safety in the management of PBM.

A critical innovation in our protocol is the preoperative pla...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
ENDOFLATOR 40	STORZ	UI400
ENDOPATH XCEL Trocars	ETHICON	B12LP
ENDOPATH XCEL Trocars	ETHICON	B5LT
HARMONIC 700 with Advanced Hemostasis	ETHICON	HAR736
HOPKINS Rubina NIR/ICG telescopes	STORZ	26003BRA
The Autotome RX Cannulating Sphincterotome	Boston Scientific	M00545170	Autotome RX 44 Cannulating Sphincterotome
The Fujifilm ED-580XT Duodenoscope	Fujifilm	ED-580XT
The Jagwire High Performance Guidewire	Boston Scientific	M00556581	Jagwire Guidewire ST
Weck Hem-o-lok Polymer Locking Ligation System	WECK	544220 Medium
Zimmon Pancreatic Stent	COOK MEDICAL	SPSOF-5-7