BACKGROUND Difficult airway is a significant cause of anesthesia-associated death and disability. Currently, physical examinations of thyromental distance, mouth opening, Mafampaii classification, etc. combined with X-ray, computed tomography (CT), and other imaging technologies are mainly used to evaluate difficult airways. However, in many special cases, i.e. , emergency surgery, imaging examinations cannot be completed preoperatively. Such patients' airway can only be evaluated through general physical examination, which inevitably increases the likelihood of an unexpected difficult airway during anesthesia. CASE SUMMARY We report a rare case of difficult intubation because of severe upper trachea distortion after induction. Emergency holmium laser lithotripsy was performed under transurethral ureteroscopy because the patient had anuria for 4 d and a creatinine level of 890 μmol/L. Due to the urgency of the condition, chest radiography or chest CT was not examined before surgery and the anesthesiologist did not evaluate the airway adequately, resulting in an unexpected difficult airway. CONCLUSION The incidence of tracheal malformation and tracheal stenosis is extremely low, but the risk of hypoxia and even death due to difficult airways is extremely high for such patients. It is recommended to complete preoperative imaging examinations of the airway. For life-threatening emergency patients, a pre-anesthesia reassessment should be performed and surgeons should be prepared to prevent and manage the difficult airway.