Percutaneous nephrological fistulae are divided into internal and external fistulae, which are used for natural drainage of kidney stones or cysts or abscesses that have formed in the kidney. The external fistula is a penetrating tunnel in the posterior lumbar region, near the anatomical location of the kidney, and is tapped into the kidney for drainage. If the drainage is clear 5-7 days after surgery, the drainage tube can be clamped closed and can be removed after 1 day without abnormalities and without more bloody or purulent exudate. For example, when there is a kidney stone, it can enter the bladder smoothly through this internal fistula and then be discharged through urine. The endostomy tube is kept for at least 30 days and can be removed after drainage is complete. If there are still stones or cysts, the endostomy tube should be replaced.