Bladder neck contracture is another important bladder neck obstruction problem. The so-called bladder neck refers to a tubular structure that extends about 1 to 2 centimeters from the internal urethral opening into the urethra. It includes the internal sphincter, but the internal sphincter is not the entire bladder neck. Bladder neck contracture can be divided into congenital and acquired in terms of etiology. Congenital ones often have no other clear causes except for local typical pathological changes, and are more common in men; acquired ones are often caused by local chronic inflammation such as posterior urethritis, prostatitis, trigonitis, etc. Congenital ones are more common in children, and they often have symptoms of urination disorders before the age of six, but it is not uncommon for them to develop the disease after the age of 20 or 30.