Which patients are less likely to have successful surgery? Patients with scar formation in the lacrimal duct and dacryocystic contracture due to previous lacrimal surgery; 4. Patients who are young and have a strong scar proliferation ability are more likely to have scar obstruction at the stoma; 5. Patients who have traumatic injuries that lead to dislocation of the dacryocystic sac; 6. Patients with combined developmental abnormalities of the maxillofacial region and the nasal region. Patients with the above conditions are more difficult to operate, and the possibility of postoperative recurrence increases, but patients do not need to be too anxious, we will apply appropriate preventive measures during the operation, in case of failure, we can also consider re-operation or other methods of treatment.