Ureteral stricture is a medical condition characterized by the narrowing or blockage of one or both ureters, the tubes that carry urine from the kidneys to the bladder. This can result from scar tissue caused by trauma or injury to the urethra or pelvis, enlarged prostate, cancer, sexually transmitted infection, or radiation therapy. The obstruction can lead to impaired urine flow, difficulty during urination, and urinary tract infection.