After kidney stone surgery, a urinary catheter needs to be left in place for about 1-3 days for the following reasons: 1. After surgery, because the anesthesia is not fully awakened, the patient cannot urinate on his own, and if the catheter is not left in place, the patient will experience urinary retention; 2. After surgery, there may be bleeding in the urinary tract, and if the catheter is not left in place, the blood accumulates in the bladder, and a hematoma of the bladder may be formed, which can increase the difficulty of the patient in urination. Symptoms. At the same time, the hematoma in the bladder is easy to combine with infection, which can cause bladder abscess or cause recurrent cystitis and other changes.3. After kidney stone surgery, a ureteral stent tube will be left in the body, and the purpose of short-term catheterization is to empty the bladder sufficiently, so that the urine in the bladder won’t reflux through the ureteral stent tube to the kidneys. The catheter will be removed after the patient has fully recovered from surgery and anesthesia, so that the patient will not be asked to hold back urine to prevent reflux of urine into the kidneys, which can reduce the probability of pyelonephritis infection or reduce the symptoms of low back pain.