Histological, laboratory, and X-ray findings after repair of the common bile duct with a Teflon graft

In Situ Tissue Engineering of the Bile Duct Using Polypropylene Mesh-Collagen Tubes

Multiple attempts have been made to replace biliary defects with a variety of materials. Recently, successful biliary reconstruction using the Gore-Tex vascular graft has been reported experimentally and clinically We designed a new artificial bile duct consisting of collagen sponge and polypropylene mesh. We presently evaluated the feasibility of using this prosthesis as a scaffold for bile duct tissue regeneration in a canine model. Our prosthesis, a sponge made from porcine dermal collagen, is reinforced with a polypropylene mesh cylinder. We used the prosthesis to reconstruct the middle portion of the common bile duct in seven beagle dogs to evaluate its efficacy. While one dog died of biliary stricture 8 months after operation, six survived without problems to scheduled time points for tissue evaluation at 1 to 12 months. All prostheses had become completely incorporated into the host. A confluent epithelial lining was observed within 3 months. In cholangiograms the prosthesis displayed long-term patency in the six dogs and provided satisfactory bile drainage for up to 12 months. Our graft thus shows promise for repair of biliary defects and should lead to development of a new treatment for biliary reconstruction.

Endoluminal reconstruction of the canine common biliary duct

PURPOSE

Extrahepatic biliary duct injuries such as transections, stenoses, and biliary leaks are well-known complications of upper abdominal surgeries. The popularization of laparoscopic cholecystectomies in the early 1990's resulted in an increase in the numbers of these reported injuries. The surgical repair of these injuries may be challenging. In this feasibility study, we were presented with the opportunity to evaluate a novel polytetrafluoroethylene (PTFE) covered stent graft that could be useful in common bile duct reconstructions. The long-term goal of this research is to offer the surgeon a new technique for reconstructing the biliary duct or repairing biliary strictures.John G. Zografakis MD, was the first place winner in the Basic Sciences Resident Competition at the Ohio American College of Surgeons meeting.

METHODS

Seven dogs were originally enrolled in the study. After general endotracheal anesthesia and open cholecystectomy, the common bile duct was identified in each dog. A guide wire was then passed through the neck of the cystic duct, anterograde into the common bile duct, through the Ampulla of Vater and into the duodenum. A stent graft delivery system was placed over the wire, and the covered stent graft was deployed within the lumen of the common bile duct. Study outcomes included graft patency and assessment of the bio-incorporation of the graft and the effectiveness of the graft to drain the biliary system as determined by liver enzyme tests.

RESULTS

Three implants were harvested at 1 month, and 2 grafts were harvested each at 3 months and 6 months postoperatively. All of the stent grafts were patent. Liver enzyme tests revealed that all dogs had increased serum levels of alkaline phosphatase, alanine aminotransferase (ALT) serum glutamate pyruvate transaminase (SGPT) and aspartate aminotransferase (AST) serum glutamic oxaloacetic transaminase (SGOT). Four dogs had increased total bilirubin. These increases were all measured in the immediate postoperative period. Peak levels for each measure were reached between 4 and 10 days and then gradually trended toward baselines by 1 month postoperatively. We did not observe meaningful changes in serum albumin or total protein. One dog suffered a tear in the common bile duct due to balloon overinflation. This tear was suture repaired when the graft was implanted. However, bile leakage was found when the graft was harvested at 1 month postoperatively. There appeared to be minimal bio-incorporation of the stent-grafts into the biliary duct wall, and there was no pronounced inflammatory response found in the duct wall or surrounding tissues.

CONCLUSIONS

We are encouraged by these early results. Additional studies are planned to evaluate a self-expanding PTFE covered stent graft and a percutaneous delivery system.

Small intestinal submucosa as a bioscaffold for biliary tract regeneration

BACKGROUND

Porcine small intestinal submucosa (SIS) biograft is used as a bioscaffold for regeneration of a variety of tissues. To date, SIS has not been used as a biliary tract graft. The purpose of this study was to evaluate the feasibility of using SIS as a scaffold for bile duct tissue regeneration in a canine model.

METHODS

Fifteen, 25- to 35-kg mongrel dogs underwent midline laparotomy and exposure of the common bile duct. Nine dogs had a longitudinal choledochotomy and a 2- x 1-cm elliptical patch of 4-ply SIS placed using 6-0 polypropylene suture. Six dogs had the anterior two thirds of the bile duct resected and a 2- to 3-cm tubularized 4-ply SIS interposition graft placed. Dogs were killed at intervals ranging from 2 weeks to 5 months. Before killing, liver function tests (alkaline phosphatase [U/L] and total bilirubin [mg/dL]) were evaluated, cholangiograms were performed, and the bile duct was examined histologically.

RESULTS

Fourteen out of 15 dogs survived and were healthy at the time of killing. The one failure was a result of a bile leak in a patched animal. The SIS showed signs of incorporation with infiltration of native fibroblasts, blood vessels, and biliary mucosa within 2 weeks. Within 3 months the SIS graft was replaced with native collagen covered with a biliary epithelium. No changes occurred at 5-month follow-up. One animal with an interposition graft developed a stricture at the proximal anastomosis within 2 months. In the remaining dogs, liver enzymes were normal, and the caliber of the common bile duct remained normal.

CONCLUSIONS

SIS can be used for regeneration of bile duct tissue in a canine model. In 13 of 15 dogs SIS resulted in regeneration of canine common bile duct when used as a patch or as an interposition graft. The potential for the use of SIS as a patch for biliary stricturoplasty, or as an interposition graft for repair of complex biliary injuries is encouraging.

Fascioperitoneal graft with T-tube drainage for patching bile duct defects

Reconstruction of choledochal wall defects in an experimental dog model by T-tube plus fascioperitoneal graft and an evaluation of the short-term results were the aims of this study. Twelve randomly selected mongrel dogs of both sexes, having an average weight of 22.15 +/- 1.85 kg, were anaesthetized with ketamine HCI and xylazine and underwent laparatomy. The front wall of choledoch canal were excised with its all layers 0.5 cm in diameter at the distal part of the cystic duct junctions. These defects were repaired by using grafts prepared of the same diameter from the dorsal fascias of rectus muscles and peritoneum. T-tubes were introduced into the common ducts on the proximal part of the grafts. One of the animals died in the postoperative period due to evantration. T-tube cholangiograms on the twelfth day did not indicate any extravasation or stricture. Histopathological examination of the graft regions on the sixtieth day revealed that the epithelialization had commenced on the border between the bile epithelium and grafts. Based on these early findings, it was suggested that if supported by further studies it may be thought of as a clinical method.

Non-surgical trauma to the extrahepatic biliary tract

Non-surgical trauma to the extrahepatic biliary tract is uncommon and encountered only rarely by surgeons outside specialist hepatobiliary centres. Such injury often results in significant morbidity and mortality. This review outlines the incidence, classification, mechanisms of injury, presentation, diagnostic techniques and management options. Depending on the type of biliary injury identified, an optimal method of repair is suggested. Recommendations are made for surgeons who encounter this type of injury and do not have the appropriate expertise for definitive management.

Circumferential choledochoplasties with autologous venous and arterial grafts

Circumferential choledochoplasties with vascular grafts have rarely been attempted either experimentally or in clinical practice. In this study, choledochoplasties using autologous venous and arterial grafts were performed in rats. Sixty-four rats were randomly selected into five treatment groups: A) venous interpositional graft replacement of a choledochus gap without a stent; B) venous graft with prolene stent; C) venous graft with polyethylene stent; D) arterial graft; E) a control group with simple resection between ligatures in the choledochus. The operative mortality in treatment groups B, C, D, and E, was 0, and 13% in group A. At 12 weeks follow-up, all the rats in group E had died, whereas, 52.2% (P < .05) of the rats in group A, 30% of the rats in group B, 57% of the rats in group C, and 92.8% of the rats in group D survived treatment. Surviving animals were sacrificed at 3 months for further examination. The morphology and caliber of the common bile duct of these rats were normal in 25% of the rats in group A, 33% of the rats in group B, 25% of the rats in group C, and 84.6% of the rats in group D. Proximal dilations were found in the rats presenting with abnormal morphology. The dilations were less marked in the group treated by arterial choledochoplasties. Laboratory and clinical cholestatic parameters were within normal ranges in the presence of common bile duct dilations less than four times the normal duct caliber.(ABSTRACT TRUNCATED AT 250 WORDS)

Total and subtotal replacement of the common bile duct: effect of transhepatic silicone tube stenting

The effect of silicone tube stenting on the outcome of total and subtotal replacement of the bile duct with autologous vein was investigated in experiments performed in pigs. All but one of the unstented animals developed dense strictures of the extrahepatic ductal system. This complication was abolished by the use of silicone stents passed transhepatically. The vein autografts in the stented animals underwent progressive shortening with elongation of the distal common bile duct so that beyond four months only one suture line was encountered, and no recognisable venous element was detectable on histological examination. Apart from minor dilatation of the intrahepatic biliary tree encountered in some animals, all the surviving stented animals progressed well and had normal serial liver function tests.