Non-surgical treatment of post-surgical bile duct injury: Clinical implications and outcomes

AIM:To investigate the prognostic factors determining the success rate of non-surgical treatment in the management of post-operative bile duct injuries(BDIs).METHODS:The study patients were enrolled from the pancreatobiliary units of a tertiary teaching hospital for the treatment of BDIs after hepatobiliary tract surgeries,excluding operations for liver transplantation andmalignancies,from January 1999 to August 2010.A total of 5167 patients underwent operations,and 77patients had BDIs following surgery.The primary end point was the treatment success rate according to different types of BDIs sustained using endoscopic or percutaneous hepatic approaches.The type of BDI was defined using one of the following diagnostic tools:endoscopic retrograde cholangiography,percutaneous transhepatic cholangiography,computed tomography scan,and magnetic resonance cholangiography.Patients with a final diagnosis of BDI underwent endoscopic and/or percutaneous interventions for the treatment of bile leak and/or stricture if clinically indicated.Patient consent was obtained,and study approval was granted by the Institutional Review Board in accordance with the legal regulations of the Human Clinical Research Center at the Seoul National University Hospital in Seoul,South Korea.RESULTS:A total of 77 patients were enrolled in the study.They were divided into three groups according to type of BDI.Among them,55 patients(71%)underwent cholecystectomy.Thirty-six patients(47%)had bile leak only(type 1),31 patients had biliary stricture only(type 2),and 10 patients had both bile leak and biliary stricture(type 3).Their initial treatment modalities were non-surgical.The success rate of non-surgical treatment in each group was as follows:BDI type 1:94%;type 2:71%;and type 3:30%.Clinical parameters such as demographic factors,primary disease,operation method,type of operation,non-surgical treatment modalities,endoscopic procedure steps,type of BDI,time to diagnosis and treatment duration were evaluated to evaluate the prognostic factors affecting the success rate.The type of BDI was a statistically significant prognostic factor in determining the success rate of non-surgical treatment.In addition,a shorter time to diagnosis of BDI after the operation correlated significantly with higher success rates in the treatment of type 1 BDIs.CONCLUSION:Endoscopic or percutaneous hepatic approaches can be used as an initial treatment in type1 and 2 BDIs.However,surgical intervention is a treatment of choice in type 3 BDI.

Texture development and grain boundary phase formation in Ce-and Ce-La-substituted Nd-Fe-B magnets during hot-deformation process

In this study,the influence of Ce-and Ce-La-substitution for Nd in Nd-Fe-B magnets on their magnetic and microstructural changes in the course of the hot-deformation process was investigated to gain insight into further reducing the Nd content in fine-grained Nd-Fe-B hot-deformed magnets.We found that the[001]texture and microstructure of the RE-rich grain boundary phases,which are the factors that de-termine the remanence and coercivity of hot-deformed magnets,were deteriorated by the Ce-and Ce-La-substitution.This is because the volume fraction of the RE-rich liquid formed in the grain boundaries during the hot-press and hot-deformation decreased due to the Ce-and Ce-La-substitution,thereby in-creasing the friction between the 2:14:1 grains while the c-axes of grains were aligned by grain rotation and decreasing the RE concentration of grain boundary phases.In particular,the Ce-La-co-substitution further prevented the liquid formation within the grain boundaries of the magnets during hot-press and hot-deformation because the wettability of the RE-rich liquid on the 2:14:1 grains became poor when La was substituted for Nd in the 2:14:1 grains.These results indicate that there is room for further im-provement in both the remanence and coercivity of the Ce-and Ce-La-substituted magnets by intro-ducing additional liquid into the grain boundaries prior to hot-press and hot-deformation.By applying the Nd-Cu infiltration process to the melt-spun ribbons(intermediate infiltration,I-infiltration),both the remanence and coercivity of the Nd-saving(Nd 0.7 Ce 0.3)-Fe-B and(Nd 0.7 Ce 0.225 La 0.075)-Fe-B hot-deformed magnets were successfully improved.