Biliary lesions and leaks test skills of interventionalists
While most biliary interventions remain the province of endoscopists, interventional radiologists will still see a fair share of strictures and leaks. Whether opening up a tumor-related blockage or rectifying a surgical slipup, practitioners should be prepared to perform some technically complex procedures.
Sometimes endoscopic access to the biliary tree is simply not possible, hence the need for a percutaneous approach, according to Prof. Andy Adam, a professor of interventional radiology at King's College London and president of 2006 ECR.
Interventional radiologists can generally help out, although they need to appreciate when to refuse, he said. Images acquired prior to intervention should reveal if the procedure is worth attempting. For example, if a long-standing obstruction has caused lobe atrophy, or a patient with a large liver tumor has minimal biliary tree dilation in the unaffected part of the organ, then leaving well alone is likely to be the best option.
"People may come to see you and say, 'Mrs. Smith is jaundiced, and she has an obstruction we can see on ultrasound. Could you drain her?' The usual answer is yes, but it is not always appropriate," he said.
Most interventional treatment of malignant liver disease is now performed with metallic stents. These have a higher patency and lower obstruction rate than plastic stents. The lower cost of plastic stents is counterbalanced by the lower re-intervention rate associated with metallic stents. Plastic stents are still recommended for procedures involving the duodenum, where straightening metal stents can dig into the wall, leading to duodenitis, bleeding, and perforations. The use of metal stents also allows for drainage and stenting to be performed in a single setting, Adam said. He recommends use of a 13-French stent with a 7-F introducer. A 4-F access catheter is left in place overnight.
"You might as well stent there and then because you achieve much better drainage through a 13-F stent than through an external catheter," Adam said during a course at the 2005 RSNA meeting.
Dr. Peter Mueller, head of abdominal imaging at Massachusetts General Hospital in Boston, agrees with the need to avoid delays in biliary interventions. Cases complicated by sepsis, hemobilia, or cholangitis should not be rushed, however, he said.
"Sometimes just waiting a few days is the best thing for patients," he said. "They recover, and then it is amazing how much easier manipulating the catheter can be. All of the issues that you are likely to face in biliary intervention can be solved if you wait."
The incidence of surgically induced leaks and lesions has increased following the introduction of laparoscopic cholecystectomy, said Dr. Mario Bezzi, an assistant professor of radiology at the University of Rome.
"This is a very important problem because it is a significant cause of litigation worldwide," he said. "In the U.S., 20% of all claims are for laparoscopic surgery, and 50% of these are due to biliary injury; 17% of all indemnity paid in the U.S. is for biliary injury that occurs during laparoscopic surgery."
Global incidence of biliary injury from laparoscopic cholecystectomy has now stabilized at about 0.2% to 0.8%. This remains higher than rates recorded for open surgery, although it is a significant improvement on the "almost catastrophic" figures from the early 1990s, Bezzi said.
In general, surgeons who have performed 50 to 100 such procedures are most likely to make a mistake. Physicians in this group will have gained confidence from their first 50 laparoscopic cholecystectomies but will not yet have the expertise that comes from 100 or more interventions, he said.
Postoperative analysis of videotapes can still leave surgeons in the dark as to why an injury occurred. Extensive electrocauterization around the bile duct area was a common cause of injury during the early 1990s. Awareness of this pitfall has led to a reduction in injuries. Blind attempts at hemostasis with clamps and clips and misidentification of the common bile duct as the cystic duct are still significant issues.
"When you see that the patient has five or seven clips, you know that something happened during surgery and the surgeon probably tried to place the hemostatic clips blindly," he said.
When biliary injury does occur, diagnosis needs to be prompt to avoid infection and complications. CT and ultrasound can assess whether there is a collection of fluid, while MRI and scintigraphy should reveal leaks from extravasation of contrast. Direct opacification, either with an endoscopic technique or percutaneously, is used to define the anatomy.
The next step is to drain the bile ducts. Assistance from a surgeon will likely be required to divert bile flow from the liver and decompress the bile duct. The site of any leak can then be confirmed and ductal damage assessed.
Interventional radiologists should be equipped to treat minor injuries to the biliary tree, Bezzi said. Major injuries may sometimes be tackled with percutaneous techniques, though these cases will usually be referred for additional surgery.
"If repeated balloon dilatation and stenting fails, reconsider surgery," Bezzi said. "Try to be humble, and ask the surgeon, 'Is there something we can do for this patient?'"