Inclusion Criteria:  Abdominal CT scanning indicating ureteral stones or kidney stones that are less than 2 cm in diameter, and patients who are planning to undergo URL surgery. Age between 18 and 80 years old and capable of providing written informed consent; In general, the heart, lung, liver and kidney function are in well condition, able to tolerate surgical treatment, and comply with research requirements.  Exclusion Criteria:  Before the onset of urolithiasis, the patient has suffered from obvious overactive bladder syndrome, or chronic lower urinary tract infection, or urinary anatomic deformities, or had previously undergone urinary tract plastic surgery. Other severe complications, infections, etc. that the researchers believe may make the subject unsuitable for this study. The patient is not a local resident and insists on returning to his howetown for D-J stent removal after the URL operation（so that we are unable to retrieve the D-J stent and conduct the in vitro experiment）. The patient refuses to sign the informed consent.