Final answer:
The procedure for treating urine flow obstruction via the insertion of a thin tube into the ureter is known as ureteral stent placement.
Step-by-step explanation:
The insertion of a thin narrow tube into the ureter to treat urine flow obstruction is called ureteral stent placement. This medical procedure involves the placement of a stent to expand the ureter and allow urine and any obstructing stones to pass. This is often considered when a kidney stone causes a blockage and an alternative to other treatments such as lithotripsy or surgery is needed. The ureters, which are retroperitoneal, propel urine towards the bladder through peristalsis. When blocked by a stone, a stent can effectively create a passageway to relieve the obstruction and facilitate the flow of urine.