Role of Bilioenteric Bypass in the Management of Biliary Stone Disease
Executive Summary
Biliary stone disease is a significant health concern in the United States, with approximately 10% of the 500,000 patients undergoing annual cholecystectomies estimated to have stones within the common bile duct (CBD). While many stones are secondary (originating in the gallbladder), primary stones—those arising within the bile ducts themselves—present a more complex management challenge due to the frequent need for surgical intervention and definitive drainage procedures.
The primary objective of surgical management is to provide wide open drainage to the biliary tree, thereby avoiding stasis and preventing the formation of recurrent "de novo" stones. Current clinical standards utilize risk stratification based on laboratory and ultrasound findings to guide treatment. For definitive management, two primary surgical options exist: choledochoduodenostomy and hepaticojejunostomy. Recent advancements favor laparoscopic approaches for these procedures, offering advantages such as shorter hospital stays, reduced pain, and superior visualization of the surgical field.
Epidemiology and Pathophysiology of Biliary Stones
Prevalence and Risk Factors
General Population: More than 20 million Americans are estimated to have cholelithiasis.
CBD Stone Prevalence: In patients under 60 years of age, the prevalence of CBD stones is 8–15%. This increases significantly in elderly populations to 15–60%.
Primary Stones: These stones originate within the intra- or extra-hepatic biliary tree. They are often associated with older adults who have large bile ducts or periampullary diverticula.
Asymptomatic Cases: Between 3% and 5% of patients with choledocholithiasis remain asymptomatic.
Mechanism of Primary Stone Formation
Primary stones are thought to result from a combination of:
Biliary Stasis: Often caused by abnormalities of the sphincter of Oddi or large bile ducts.
Bacterial Infection: Certain bacteria produce enzymes that deconjugate bilirubin diglucuronide. This leads to the precipitation of calcium bilirubinate, forming biliary sludge and eventually stones.
Clinical Diagnosis and Risk Stratification
The diagnosis of choledocholithiasis is typically established through a combination of laboratory testing and imaging studies (primarily ultrasound). Localization is best achieved via magnetic resonance cholangiopancreatography (MRCP) and endoscopic retrograde cholangiopancreatography (ERCP).
ASGE Risk Predictors
The American Society for Gastrointestinal Endoscopy (ASGE) uses specific criteria to stratify patient risk:
Risk Stratification Categories
High Risk: Presence of at least one "very strong" predictor and/or both "strong" predictors.
Intermediate Risk: Presence of one "strong" predictor and/or at least one "moderate" predictor.
Low Risk: No predictors present.
Technical Considerations in Laparoscopic Approaches
The laparoscopic approach is safe and provides results comparable to open surgery regarding perioperative morbidity and mortality.
Patient Positioning: Supine with arms padded. The operative table is tilted during the procedure to optimize exposure.
Trocar Placement: While placement varies by body habitus, a standard configuration includes:
12-mm port in the midline.
12-mm port for the camera (right hemiabdomen).
High right lateral subcostal 5-mm port.
High left subcostal midaxillary 5-mm port.
Optional 5-mm port in the left hemiabdomen for an assistant.
Visualization: Advanced laparoscopic skills are required to manage the different angles of visualization and the precise suturing necessary for the anastomosis.
Surgical Management Strategies
Surgery is indicated when a patient requires definitive treatment, particularly those who have undergone multiple failed endoscopic procedures to evacuate recurrent stones.
Choledochoduodenostomy
This procedure involves anastomosing the duodenum to the common bile duct. It is the preferred choice for patients with a history of gastric bypass who develop bile duct stones.
Historical Context: First performed by Bernhard Riedel in 1888; William J. Mayo reported successful treatment of a strictured CBD using this method in 1905.
Technical Requirements: Successful outcomes are facilitated by a CBD dilated to >12–15 mm.
Laparoscopic Advantages: Provides magnification, different angles of visualization, and precise anastomosis.
The Diamond-Shaped Anastomosis: Modern techniques favor a 4-quadrant, diamond-shaped anastomosis. By creating a wide opening low on the CBD, the risk of "sump syndrome" (a potential complication of the procedure) is minimized.
Surgical Steps for Choledochoduodenostomy
Identification and exposure of the CBD.
Wide Kocher maneuver of the duodenum to allow for a tension-free anastomosis.
Longitudinal choledochotomy (>2 cm) and complete clearance of biliary tree stones.
Longitudinal duodenotomy.
Diamond-shaped anastomosis using 5-0 absorbable running stitches.
Hepaticojejunostomy
First described by Jacques-Ambroise Monprofit in 1908, this procedure uses a loop of small intestine (Roux-en-Y) to reconstruct the biliary tract.
Procedure Specifics: Unlike choledochoduodenostomy, this involves a complete transection of the main bile duct and closure of the distal duct stump.
Clinical Applications: Used in various procedures, including pancreatoduodenectomy and the repair of iatrogenic bile duct injuries.
Follow-up Considerations: Some surgeons suggest using a "short limb" for the Roux-en-Y to allow for future endoscopic examination.
