This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'In which pa of the common bile duct does biliary stricture develop after laparoscopic cholecystectomy? \nSelect and explain. \nA. Upper, B. Middle, C. Lower, D. All side with equal frequency', 'role': 'user'}, {'content': "Answer: A \nExplanation: Following laparoscopic cholecystectomy, biliary stricture most commonly develop at the upper pa of the common bile duct. Postoperative biliary stricture occur as a result of unexpected ischemic injury or a misplaced surgical clip. Treatment involves stricture dilatation using a balloon dilator or graduated catheter dilator over a guide wire. Grades of site of stricture formation: Grade I: occur more than 2 cm from the confluence of right and left hepatic duct Grade II: involve common hepatic duct, less than 2cm from the confluence Grade III: within 1 cm of confluence Grade IV: involve hepatic confluence Ref: Sabiston Textbook of Surgery, 17th Edition, Page 1623 ; Liver and Biliary Tract Surgery: Embryological Anatomy to 3D-Imaging and transplant innovations By Constantine Ch Karaliotas, Pages 180-81 ; Schiff's Diseases of the Liver By Eugene R. Schiff, 11th Edition, Pages 78-80", 'role': 'assistant'}]