Abstract: To investigate the treatment of acute renal failure due to ureteral stone obstruction. METHODS: Thirty-two cases of ureteral stone obstruction with acute renal failure were treated with ureteroscopic direct view pneumatic ballast lithotripsy. RESULTS: After the operation, all patients’ renal failure symptoms were reduced or disappeared, and blood Bun and Cr were reduced or normalized to different degrees. Conclusion: Ureteroscopic direct view pneumatic ballast lithotripsy for ureteral stone obstruction with acute renal failure has the advantages of safety, reliable efficacy and little damage, and can deal with bilateral ureteral lesions at the same time. Acute post-renal obstructive renal failure is one of the common urological emergencies; and ureteral stones are a common cause of upper urinary tract obstruction. 32 cases of acute renal failure caused by ureteral stone obstruction were treated by direct ureteroscopic pneumatic ballast lithotripsy [1] in our hospital from March 2000 to October 2007 with satisfactory results, which are reported below. 1 Data and methods 1.1 General data The 32 cases in this group, 23 men and 9 women. Age 21-63 years old, average 42 years old, including 19 cases of bilateral ureteral stones, 6 cases of renal atrophy on the opposite side of one ureteral stone, 4 cases of nephrectomy on the opposite side of one ureteral stone, and 3 cases of congenital isolated renal ureteral stone. The site of obstruction was upper ureteral stones in 8 cases, middle ureteral stones in 13 cases, and lower ureteral stones in 11 cases. There were 7 cases of combined renal stones. 1.2 Clinical manifestations There were 9 cases of anuria and 23 cases of oliguria in this group. Urea nitrogen ranged from 19.5 to 55.4 mmol/L, blood creatinine ranged from 550 to 1,300 mmol/L, blood potassium ranged from 3.9 to 6.7 mmol/L, and all 32 cases had different degrees of metabolic acidosis. Ultrasound and abdominal plain film examination were performed in 32 cases, and all of them had different degrees of hydronephrosis. There were 22 positive stones, 10 negative stones, and all negative stones were clearly diagnosed by CT examination. 1.3 Treatment All patients were given anti-infection, correction of acidosis and water-electrolyte imbalance, symptomatic support treatment, and hemodialysis in severe cases after admission. All 32 cases underwent ureteroscopic direct-view pneumatic ballistic lithotripsy under epidural anesthesia in the emergency, among which 13 cases were unilateral lithotripsy and 19 cases were bilateral ureteral lithotripsy at the same time. After the operation, renal function was gradually restored, and after the condition was stabilized, 7 cases were complicated by renal calculi, 3 cases of complicated renal calculi were treated with open surgery for stone extraction, and 4 cases were treated with ESWL. 2 Results Of the 32 cases with 51 ureteral calculi, 45 cases were successfully lithotripsed at one time, 6 cases had stones slipped into the renal pelvis and were left with double J tubes, and ESWL was performed after the condition was stabilized. 88.2% of the cases were successfully lithotripsed at one time, and 100% of the cases were left with double J tubes. The success rate of one-time lithotripsy was 88.2%. There was no death in this group, and the patients’ symptoms disappeared at the time of discharge. 26 cases had normalized urea nitrogen and blood creatinine, and 6 cases had decreased urea nitrogen and blood creatinine to below 12.0 mmol/L and 155 μmol/L, respectively. Patients with acute renal failure due to ureteral stone obstruction are in acute condition with severe and complicated symptoms and poor tolerance to surgery, especially those with acute obstruction on the basis of chronic renal insufficiency, often with multi-system damage, and their condition is more complicated and requires emergency management. The main conflict of this disease is obstruction, and if the obstruction is not removed, the renal function will be further aggravated, and other treatment measures will not be effective. Therefore, we believe that the management of this disease should be based on releasing the obstruction as soon as possible with less damage to the patient to protect the renal function, while striving to remove the stone if the condition permits. Open surgical stone extraction (including one-stage surgery with simultaneous stone extraction on both sides or surgical stone extraction on one side and percutaneous nephrostomy on the opposite kidney) is highly traumatic and takes a long time, which results in high surgical risk, many complications, and slow postoperative recovery [2], and some patients cannot tolerate surgery and do not conform to the above treatment principles; some reports use cystoscopic retrograde ureteral intubation to relieve obstruction with safe and effective features and little trauma However, the success rate is low, with a success rate of 77.8%. Most of the reasons for failure of intubation are local adhesions or polyps, and the ureteral stones cannot be treated at the same time. Ureteroscopy and pneumatic ballistic lithotripsy have high success rate, complete stone extraction, less damage, and fast recovery, which makes more than 95% of ureteral stones no longer need to be removed by incision [4], and the ureteroscope can treat local adhesions or polyps under direct vision, thus increasing the success rate of tube placement, and at the same time, the pneumatic ballistic lithotripsy device can be used to lithotripsy ureteral stones at the same time. It has the advantages of one-time resolution of stone obstruction and high success rate compared with the method of retrograde intubation for urinary drainage [5], and patients recover quickly after surgery. The success rate of ureteroscopic one-time placement under direct vision was 100% in 32 cases, and the success rate of one-time lithotripsy was 88.2%. The success rate of ureteroscopic pneumatic ballast lithotripsy for ureteral stones was reported to be 92%-98% in China [6], and the success rate of lithotripsy in our group was 88.2%, which was relatively low. We believe that the general condition of patients with acute renal failure is poor, and due to water and sodium retention and infection, the ureter is edematous, some patients are prone to bleeding, which affects the visual field and increases the difficulty of operation, and the ureter is obviously dilated and the stone is easy to slide. For patients with obstructive acute renal failure, a stent tube should be left in place after endoluminal surgery. The double J tube has good internal stenting and internal drainage, which is conducive to the discharge of lithotripsy and prevention of ureteral stenosis. The patients recovered their renal function after surgery and were cured by elective ESWL with good prognosis.