Most fracture surgeries require a urinary catheter, such as lower extremity surgery, pelvic surgery or some spine surgeries, which require lumbar anesthesia or combined lumbar and rigid anesthesia. Generally, the sensation of urination disappears after anesthesia and the patient does not know how to defecate, and it may be necessary to insert a urinary catheter to help urinate because of the long operation time, so as to avoid the serious situation of extreme bladder fullness or even bladder rupture after the long operation time when the patient cannot urinate. In addition, urinary catheters are recommended for upper extremity surgery, such as a completely severed finger that requires finger replantation, or more complex crushing surgery on the upper extremity, because the patient is not able to urinate due to the length of the surgery, and a urinary catheter can make the urine drain.