Novel approaches have been performed in other anatomic settings which preclude ERCP, such as prior gastric surgery. The most common gastric surgery currently performed is the Roux-Y gastric bypass. In this surgery, a small gastric pouch is created and anastomosed to a limb of jejunum. The majority of the stomach, duodenum, and proximal jejunum are bypassed, making endoscopic access technically difficult. Combined laparoscopic surgical and endoscopic procedures have been described. Endoscopic access can be achieved via a gastrostomy or jejunostomy. The endoscope can be passed under surgical guidance, and an ERCP can be performed in the standard fashion. These procedures are only described in short case reports, but will undoubtedly become more common place with the prevalence of gastric bypass.
Diagnosis of choledocholithiasis is not always straightforward and clinical evaluation and biochemical tests are often not sufficiently accurate to establish a firm diagnosis. Imaging tests, particularly abdominal ultrasound, are used routinely to confirm the diagnosis. Liver function tests (LFT) can be used to predict CBD stones[4,5]. Elevated serum bilirubin and alkaline phosphatase typically reflect biliary obstruction but these are neither highly sensitive nor specific for CBD stones. Excepting obvious jaundice, a raised GGT level has been suggested to be the most sensitive and specific indicator of CBD stones. A value of greater than 90 U/L has been proposed to indicate a high risk of choledocholithiasis. However, laboratory data may be normal in as many as a third of patients with choledocholithiasis, warranting further evaluation of the CBD by imaging studies to clarify the diagnosis.
Obstruction or other biliary abnormality should be suspected if these findings are not clear.
Computed tomography (CT) may have some role in diagnosis of gallstone disease and choledocholithiasis. Many patients presenting with acute abdominal pain will undergo a diagnostic CT scan as part of the acute workup. A diagnosis of acute cholecystitis may be evident based on signs of gallbladder inflammation. Cholelithiasis may be detected on CT and often the diameter of the CBD can be measured. In the clinical setting, US may not be necessary for preoperative evaluation if the CT scan provides this information. The role of helical CT cholangiography is still in evolution, particularly in the United States. Intravenously administered contrast agents, combined with high resolution helical scans and three dimensional reconstructions that can be very useful in diagnosing choledocholithiasis[12,13]. The sensitivity of this technique can be as high as 95.5%. This technique is not widely utilized in the U.S. as the available contrast agents often cause significant nausea on administration. The availability of MRCP also limits the need for this modality.
INTRAOPERATIVE EVALUATION AND THERAPY
Intraoperative cholangiogram via the cystic duct demonstrating proximal biliary dilation and two filling defects in the CBD (Arrows).
Laparoscopic techniques can be very effective at clearing CBD stones, but significant expertise and experience is required to achieve high success rates. Stones impacted at the sphincter of Oddi are often the most difficult to extract by this technique. Long term follow up does not demonstrate a significant risk of CBD stricture or other complications for these procedures[2,29,30]. This technique is also advocated in the pediatric population by some practitioners as a way of avoiding an ERCP. Intraoperative ERCP, although often limited by the immediate availability of a qualified endoscopist, is a technique that can be very useful. This takes advantage of the preexisting anesthetic and does not prolong hospital stay by delaying the procedure[33,34]. In some instances, cooperation between the surgeon and the endoscopist can expedite the procedure. Guidewire placement, throught the sphincter of Oddi, into the duodenum via the IOC catheter can facilitate cannulation, especially for patients with difficult duodenal anatomy. In the case of an unsuccessful extraction, open CBD exploration or drainage of the duct should be considered.
ERCP has been the gold standard for preoperative diagnosis of CBD calculi. When compared to other tests such as ultrasonography and MRCP, ERCP has the advantage of providing a therapeutic option when a CBD stone is identified. Stone retrieval and sphincterotomy has supplanted surgical treatment of choledocholithiasis in many institutions[14,20]. Successful cholangiography by an experienced endoscopist is achieved in greater than 90% of patients. Complications associated with ERCP can be as high as 15% and include pancreatitis, cholangitis, perforation of the duodenum or bile duct, and bleeding. These individual complications can occur in 5%-8% of patients. The mortality rate from ERCP is 0.2%-0.5%[21,22]
Common bile duct (CBD) stones may be discovered preoperatively, intraoperatively or postoperatively. The standard preoperative workup for patients presenting with symptoms attributable to cholelithiasis includes liver function tests, and abdominal ultrasound. These tests, combined with clinical exam and history, constitute the entire workup for most patients. Abnormalities in these tests may suggest the presence of choledocholithiasis. Choledocholithiasis may occur in up to 3%-10% of all cholecystectomy patients, or as high as 14.7% in some series. This includes some patients without classic preoperative findings suggestive of choledocholithiasis. Of these asymptomatic patients, it is believed about 15% will eventually become symptomatic and require further interventional treatment.
Laparoscopic view of a choledochoscope (CS) entering the CBD via the cystic duct. The gallbladder (GB) is retracted to the left of the image.
A tendency for this disease can be inherited.
Treatment involves removing the stone using ERCP. Typically, the gallbladder is then removed to prevent a future occurrence of common bile duct obstruction.
Safe Weighing Range Ensures Accurate Results
Doctors can use a blood test of alkaline phosphatase, bilirubin and cholesterol to diagnose choledocholithiasis.
However, ultrasound demonstrating an enlarged common bile duct is the test of choice.