The removal rate, complication risk and operation time of ureteral soft scope combined with negative pressure suction sheath therapy for patients with high-load kidney stones (2-3cm) are still controversial. Therefore, the safety and effectiveness of flexible ureteroscope combined with negative pressure suction sheath in treating patients with high-load kidney stones is unknown. This study will help to solve the problems, provide a more scientific treatment strategy for clinical practice, and promote the application of negative pressure aspiration technology in the field of flexible ureteroscopy lithotripsy, providing new means and ideas for individualized treatment.

The patients enrolled in the group should complete the routine clinical diagnosis and treatment before the operation, including non-contrast CT scan of the urinary system (before surgery), urine routine, urine culture, etc. The postoperative follow-up mainly includes complications after the operation, the time of removing the D-J tube, the time of removing the urinary catheter, urine routine, urine culture, etc. The blood routine, blood chemistry, etc. should be reexamined in the outpatient department one month (4 weeks) after the operation.Patients underwent low-dose CT (DLP:0.45 mGy·cm) scans on the first day and one month after surgery.

During the operation, we will collect some data, including the time when invasive procedures start, the total operation time, the renal pelvis pressure, laser power, and total laser energy; we will also keep a backup of the operation video.

Inclusion Criteria:

1. Patients diagnosed with kidney stones with a diameter of 2-3cm by computed tomography;
2. Age > 18 years old;
3. The anatomical structure of the kidney is normal, without deformity;
4. No serious heart and lung disease (ASA grade I-III)
5. Through preoperative communication, patients and their family members indicated that they were fully aware of the condition and the choice of treatment plan, and signed informed consent and informed choice notification;

Exclusion Criteria:

1. Simultaneous operation is required for ipsilateral ureteral calculi or contralateral upper or lower urinary calculi.
2. Severe coagulation dysfunction;
3. Patients who do not sign informed consent and cannot cooperate with the study;

Age range from 18 to 75 years old; Patients undergoing flexible ureteroscopy lithotripsy in our hospital due to high-load kidney stones(2-3cm); All enrolled patients received informed consent and signed informed consent before operation.