Granulation at the porta hepatis following hepatic portoenterostomy for biliary atresia: the healing of experimental hepatoenterostomy.

After hepatic portoenterostomy for biliary atresia, granulation that formed at the porta hepatis caused biliary obstruction in seven out of 27 patients (26%). Six of the seven developed the complication during the first 6 weeks after surgery. The mortality rate was 29% (2/7). Among the same group, the incidence and mortality rate of ascending cholangitis was 19% (5/27) and 20% (1/5), respectively. The features characteristic of biliary obstruction caused by granulation, as compared with those of ascending cholangitis, were the absence of signs of infection and the lack of response to medical treatment. Quantitative analysis of the healing process of an experimental hepatoenterostomy in the rat showed that the mean thickness of the granulation formed at the anastomotic site (area, 5 x 20 mm) decreased almost constantly--from 1.49 mm on day 7 to 0.64 mm on day 42. Mucosa covered 20% of the granulation on day 7, 55% on day 14, 63% on day 21, 76% on day 28, and 92% on day 42. The increase in coverage was greatest during the second postoperative week. The results suggested that the healing of the hepatoenteostomy should be almost complete within 6 weeks. The operative method and postoperative management to prevent excessive granulation should be chosen so as to decrease the incidence of postoperative biliary obstruction.