Direct cholangiography and biliary drainage.

Direct cholangiography by percutaneous transhepatic cholangiography or endoscopic retrograde cholangiography has greatly improved diagnostic work-up of patients with known or suspected biliary obstruction. These diagnostic procedures were introduced in Denmark in the early 1970s, and technical refinements and clinical research of the methods were initiated. The Danish contribution led to definition of indications for direct cholangiography and general acceptance of the methods in daily clinical practice; nationally as well as internationally. The transhepatic cholangiography with selective catheterization of the biliary ducts permitted external drainage of obstructed ducts. The disadvantages of this technique inspired the innovation of internal biliary drainage and the invention of the biliary endoprosthesis. The endoscopic approach to the biliary tract and the technical improvements of accessory instruments led to the early introduction of therapeutic procedures, i.e. papillotomy, stone removal, biliary drainage and treatment of strictures and post-traumatic lesions. Experimental and clinical research with endoprostheses improved their function and prevented dislodgment. Clinical research documented that biliary drainage by endoprosthesis is a valuable alternative to surgical bypass in patients with inoperable biliary obstructions. Endoscopic therapeutic procedures for common bile duct stones have almost replaced conventional surgical treatment. Endoluminal imaging techniques are under evaluation and may contribute to future improvements.