Platyhelminthes are also known as flatworms because they are worms with a flat body. This is the main external morphological feature that differentiates them from nematodes (roundworms).
Even though 85 percent of kidney stones are small enough to pass during urination, fewer than 50 percent of patients chose this option. A person with a normal-size ureter can usually pass a kidney stone with a diameter less than 5 mm (about 3/16 of an inch) without significant pain or risk of kidney damage.
The pain of a kidney stone can be excruciating, so it's only natural to want to know how long it'll take to pass. The bad news is, it could be anywhere from hours to weeks--but with proper treatment, you can stay comfortable as you wait for it to pass.he kidney stone travels through the ureter into the bladder, then out through the urethra, usually in the flow of urine. The kidney stone can get stuck at any point in this journey, which can cause swelling and damage to any part of the urinary system. The longer it's stuck, the more damage it can cause.