Endoscopic Retrograde Cholangiopancreatography
Transient pancreatic enzyme elevation without significant clinical pancreatitis is an indication for prompt laparoscopic cholecystectomy with intraoperative cholangiogram on the same admission after a 24 hour cool down period. Some surgeons, particularly in training programs, perform routine cholangiography, which adds only 10-15 minutes to the case. Indications for cholangiography include history of jaundice, pancreatitis, dilated duct or evidence of stones in the duct by ultrasound, and unclear anatomy during cholecystectomy.
Contrast used for cholangiogram must be dilute (25%: 50% contrast mixed half and half with saline) so that small stones are not obscured by the density of the contrast. The table should always be set up for the contingency of cholangiography during laparoscopic cholecystectomy. The patient is rolled to the right to shift the common duct, which is close to the midline, off the density of the spinal column (see right upper quadrant anatomy).
The tip of the saline-filled cholangiogram catheter is advanced into the cystic duct only far enough to be held securely in place. Advancing too far can penetrate the back wall of the common duct, or direct the tip proximal or distal and result in uneven distribution of contrast in the duct. If introduction of the catheter is difficult because of the valves of Hyster in the cystic duct, gentle injection of saline while advancing may dilate the duct enough to allow passage. Care must be taken to eliminate all air bubbles in the catheter end, or three way stopcock, since air bubbles can be mistaken for stones.
The catheter should be aspirated to confirm placement by evidence of bile return, and to decompress a potentially dilated duct before the injection of contrast. Contrast is injected slowly under fluoroscopic control, exerting no pressure, and limiting injection to 7 cc (the approximate volume of the normal biliary system) at a time. There is real danger of exacerbating or causing pancreatitis if pressure drives contrast up the pancreatic duct. If the pancreatic duct begins to visualize, injection of contrast should be stopped. The criteria for a normal cholangiogram are complete filling of common duct and biliary radicals, no filling defects, clear visualization of ductal anatomy, and free flow of contrast into the duodenum.
An abnormal cholangiogram, as in this case, presents therapeutic options. Stones smaller than 4mm have a high probability of passing spontaneously, and some patients may be observed clinically without further intervention. In a patient who has had evidence of pancreatitis, the duct must be cleared. Administration of glucagon to relax the sphincter of Oddi, followed by flushing of the duct is relatively non-invasive if done under fluoroscopic control. Laparoscopic trans-cystic common duct exploration with a choledochoscope, after dilatation of the cystic duct with a balloon catheter can be successful in clearing the duct in skilled hands.
Laparoscopic choledochotomy requires a high degree of skill, and carries increased morbidity, especially if the common duct is not significantly dilated. ERCP with sphincterotomy in skilled hands is now routinely successful in over 95% of cases, and according to a recent NIH consensus panel is the recommended option in the majority of patients with stones documented intraoperatively and after unsuccessful intraoperative retrieval attempt. Sphincterotomy is performed on the exposed superolateral side of the papilla, and carried no farther than the junction with the duodenal wall to avoid the complication of duodenal perforation. Balloon catheter, basket, and lithotripsy adjuncts contribute to the success of ERCP. Any common duct manipulation, including ERCP carries the risk of pancreatitis.
NIH Consensus Development Conference Statement on Endoscopic Retrograde
Cholangiopancreatography (ERCP) for Diagnosis and Therapy