Operating procedures for urinary catheter change in girls with paraplegia: 1. Take the supine position, bend the knees and abduct to fully expose the vulva. 2. Use a syringe to draw out the water in the balloon of the original urinary catheter, and then remove the urinary catheter. 3. Open the first layer of the catheterization bag, wear gloves to disinfect, the order of disinfection is from the outside to the inside, from top to bottom. Open the inner layer of the catheterization kit and wear sterile gloves. 4. Lubricate the anterior end of the catheter with sterile paraffin oil or saline for 4-6 cm. Separate the labia minora and sterilize the urethral opening, the inner part of the labia minora on both sides, and the urethral opening in turn. Insert the catheter into the urethra for a length of about 4-6 centimeters, and then 5-7 centimeters when you see urine flowing out. 5. Fill the balloon with water, pull it gently to position it in the bladder, and then insert it inward for another 1 cm to complete. Catheterization is a specialized technique and it is recommended to go to the hospital to have it done by a physician.