Investigation of a New Superhydrophobic, Oleophobic-Coated Biliary Duct Stent and its Preventive Effect on Biliary Mud in Vitro

Background and AimA new type of superhydrophobic, oleophobic-coated biliary stent was created, and its characteristics and preventive effect on biliary mud deposition in vitro are studied herein.MethodsThe observational experiment included a bare stent group and coated stent group, with 10 stents per group. The groups were used in a model of the extracorporeal biliary perfusion system with bacterial infection, and the experiment was terminated when the stent was completely blocked. Changes of bile characteristics before and after the experiment, patency time, and amount of bile sludge deposition were compared between the groups. The t-test and analysis of variance were used to analyze the data.ResultsIn the bare stent group, contact angles of bile were about 80.4 degrees and 79.8 degrees before and after the experiment, respectively. There was no change in the effect of bile aversion after the experiment between the groups (P < 0.05). In the coated stent group, contact angles of bile changed from 143.3 degrees before the experiment to 135.7 degrees after the experiment; the effect of the coating decreased significantly after the experiment (P > 0.05). The patency times were 8 weeks and 23 weeks in the bare and coated stent groups, respectively (P > 0.05). Depositions of biliary mud were 47 mg and 13 mg in the bare and coated stent groups, respectively (P > 0.05).ConclusionThe superhydrophobic, oleophobic-coated biliary stent can repel bile better and play a role in preventing bile sludge deposition in the extracorporeal biliary perfusion system.

Ultrasonography and surgery of canine biliary diseases

Findings of hepatic and gallbladder ultrasonography were analyzed in 12 dogs with gallbladder and/or extrahepatic biliary tract obstruction and compared with the results of exploratory laparotomy. Hepatic ultrasonography demonstrated normal liver in 2 dogs and hepatic abnormalities in 10 animals. The following ultrasonographic diagnoses were established compared to surgical findings: gallbladder obstruction caused by bile sludge (correct/incorrect: 1/2, surgical diagnosis: choleliths in one case), gallbladder obstruction caused by neoplasm (0/1, surgical diagnosis: mucocele), gallbladder and extrahepatic biliary tract obstruction due to choleliths (3/3), extrahepatic biliary tract obstruction caused by pancreatic mass (1/1) and small intestinal volvulus (1/1). Bile peritonitis caused by gallbladder rupture (4/4) was correctly diagnosed by ultrasound, aided with ultrasonographically-guided abdominocentesis and peritoneal fluid analysis. Rupture of the gallbladder should be suspected in the presence of a small, echogenic gallbladder or in the absence of the organ together with free abdominal fluid during ultrasonography. Laparotomy was correctly indicated by ultrasonography in all cases. However, the direct cause of obstruction could not be determined in 2 of the 12 dogs by ultrasonography alone.

On the Bile Sludge Syndrome or Is Total Parenteral Nutrition Cholestasis a Surgical Disease?

In their article in this issue (Pediatrics 1985;76:905-908), Enzenauer and colleagues propose another complication of total parenteral nutrition in infants, ie, bile sludge obstruction. Their contention is that total parenteral nutrition induced a tenacious, viscid bile that produced a mechanical obstruction of the extrahepatic biliary system in their patient. The evidence supporting this hypothesis is suggestive but not totally convincing. It is true that the infant received prolonged total parenteral nutrition (for 50 days) and that he was fasted during most of the first 2 months of life. Moreover, gallbladder enlargement,1 biliary sludge, and cholelithiasis have been reported in patients receiving total parenteral nutrition.2

Bile Plugs and Bile Sludge

Doctors Bernstein, Braylan and Brough have called attention to a rare but important cause of extrahepatic biliary obstruction, namely, bile sludge. Curiously, even though bilirubin conjugation normally does not occur before birth, gallstones have been found in the bladders of stillborn fetuses; also, maternal hyperbilirubinemia over a period from the seventh to the ninth fetal month has resulted in the development of complete maturation of the glucuronyl transferase system by the time of birth. It is important to consider such sludge or even stones in young infants who have signs of biliary obstruction so that appropriate surgical intervention may be considered.

Letter to the Editor

Dr. Harris raises some interesting points about bilirubin metabolism in the fetus. She may be right in postulating that increased bilirubin production resulting in prehepatic overload is of importance in causing bile "sludge," an apt term. Hepatocellular damage may also play a role. We (pathologists) would not have thought that conjugation does not normally take place before birth. Meconium is green, and the gallbladder usually contains some bile, even in stillborns. The rate of conjugation may ordinarily be low, in part because the load of bilirubin is low, and a capacity to respond under abnormal conditions does seem, as Dr. Harris notes, to be present.