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
Indications of percutaneous nephrostomya) Stone removalb)  Ureteral obstructionc) Renal tumor resectiond) Ischemic renal failuree) Antegrade renography 
Select and explain. 
A. bcde, B. abce, C. acde, D. abde
B: abce
Answer: B: abce 
Explanation: • For HDN, DJ stenting and percutaneous nephrostomy, both are having same results but DJ stenting is less invasive.
• For pyonephrosis, percutaneous nephrostomy is better than DJ stenting.
• Percutaneous nephrostomy is occasionally essential, if not life saving, in the treatment of acute or chronic upper urinary tract obstruction.
• It is the first step in obtaining antegrade access to the kidney for various procedures.