الفهرس 
ANATOMY OF THE EXTRAHEPATIC BILIARY SYSTEMOnly 14 pages are availabe for public view
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Abstract
Choledocholithiasis, defined as the presence of gallstones in the common bile duct, is seen in about 8%-20% patients having gallbladder stones, but in about 5% of cases the gallbladder is empty.
CBDS can be caused either by primary bile duct stones that originate in the bile duct or by secondary bile duct stones that have descended from the gallbladder. In the primary stones, bilirubin is the dominant component and is associated with biliary stasis and infection. In secondary stones, cholesterol is the dominant component.
Despite the rapid increase in diagnostic modalities available to the clinician dealing with hepatobiliary disease, a detailed history and clinical examination are crucial if an accurate overall assessment is to be made.
Choledocholithiasis may come to clinical attention in a variety of ways. First, it may present with symptoms such as biliary colic and jaundice. Second, it may present with complications including acute pancreatitis, ascending cholangitis, and secondary biliary cirrhosis. Third, patients with choledocholithiasis may have incidentally discovered abnormalities on laboratory or imaging studies. Finally, some patients with choledocholithiasis remain asymptomatic and never present to their clinician.
Liver function tests (LFTs) can be used to screen for CBDS. Elevated serum bilirubin and alkaline phosphatase typically reflect biliary obstruction, but these are neither highly sensitive nor specific for CBDS .Elevated serum gammaglutamyl transpeptidase (GGT) and alkaline phosphatase(ALP) were the most frequent abnormalities in laboratory values of patients with symptomatic CBDS. However, laboratory data may be normal in as many as a third of patients with choledocholithiasis.
Complete assessment of extrahepatic obstruction often requires the use of various imaging modalities to confirm the presence, level, and cause of obstruction, and to aid in treatment plan.
It is useful to stratify patients preoperatively into low(<5%), intermediate(10-50%) and high(>50%) likelihood for CBD stones based on established clinical and biochemical indicators, including elevated liver function tests, a dilated CBD (>8mm on ultrasound ), and a history of jaundice or pancreatitis.
There are various imaging modalites for evaluation of common bile duct such as: Ultrasonography , ERCP,PTC , Endoscopic Ultrasound(EUS); MRCP; Helical CT (hCT); Intraductal Ultrasonography (IDUS), Intraoperative Cholangiography (IOC), IOUS; and choledochoscopy.
Transabdominal US remains the initial imaging test of choice in the evaluation of suspected biliary obstruction because it is noninvasive, inexpensive, and readily available. Dilated ducts are usually taken as indirect evidence of biliary obstruction.
ERCP has traditionally been considered the gold standard for imaging the biliary system, particularly if therapeutic intervention is planned .Because of its attendant risks, and the availability of safer noninvasive cholangiographic methods with comparable diagnostic abilities, ERCP is evolving into a predominantly therapeutic procedure.
None of the aforementioned technologies are ideal, and each exhibits advantages and disadvantages. optimal method of biliary imaging for the diagnosis and management of patients with biliary obstruction depends on the clinical situation.
The evaluation and treatment of choledocholithiasis has changed many times over the last 100 years. As newer and less invasive techniques emerge, the surgeon finds that he or she has many options and many paths that can lead to the successful treatment of a patient with common bile duct stones.
The aim of treatment is to extract or dissolve the stone which can be done using non-operative, interventional and surgical techniques .However, if this is not possible, the aim is then to provide drainage for the obstructed bile in order to improve the patient’s condition while waiting for definitive surgical intervention. Non-surgical procedures can also be performed postoperatively to remove retained stones. Lithotripsy techniques are complementary to both the surgical and interventional approach.
With the development of better endoscopic technologies including specialized cannulae, hyDROPhilic wires and endoprostheses, the indications and possibilities of therapeutic ERCP have dramatically expanded.
Open common bile duct exploration has become a rare procedure, but it remains a skill that surgeons require. If ERCP has failed or is not possible, if the surgeon does not have the experience and necessary tools to perform laparoscopic duct exploration, or if laparoscopic efforts have failed, then open exploration becomes necessary.
In patients for whom ERCP is not available, not possible secondary to anatomic considerations, or not successful, an alternative method of cholangiography and nonsurgical therapy is percutaneous transhepatic cholangiography (PTC) followed by transhepatic methods of stone removal.
Surgical drainage procedures have, in many instances, been replaced by endoscopic papillotomy or sphincterotomy. However, there remain situations in which surgical therapy is required.
Laparoscopic management of choledocholithiasis at the time of laparoscopic cholecystectomy is a safe and effective, single-stage treatment. Given the high success rate of laparoscopic common bile duct exploration, preoperative or postoperative ERCP and endoscopic sphincterotomy is not required in most cases.
Although laparoscopic common bile duct exploration appears to be the most cost-effective method to treat common bile duct stones. Occasionally, anatomic or physiologic considerations preclude the minimal access approach, and conversion to an open operation in such cases reflects sound judgment and should not be considered a complication.
Given the multiple alternatives available, sometimes it is difficult to decide on the right one for a particular patient. Frequently, the best path is the one the surgeon is most adept at or the one that local expertise can accomplish most safely. Sometimes, however, the safest approach is a transfer to a center where multiple treatment options are available so that the treatment can be tailored to fit each individual situation.