Clinical efficacy and safety analysis of retrograde intrarenal stone surgery for treatment of upper urinary calculi

Objective To evaluate efficacy and safety of retrograde intrarenal stone surgery for treatment of upper urinary calculi. Methods The clinical data of 640 patients with upper urinary tract calculi treated by retrograde intrarenal stone surgery (RIRS) in Renmin Hospital of Wuhan University from April 2016 to January 2019 were retrospectively analyzed. There were 424 males and 216 females. The awerage age was (46.2±12.8) years old, ranging 18 to 76 years old. The maximum diameter of the stone is (1.4±0.7) cm, ranging 0.6-3.2 cm. There were 126 cases with inferior calculi and 514 cases with non-lurgical calculi. There were 196 cases with unilateral ureteral calculi, 118 unilateral ureteral calculi cases with renal calculi, 236 cases with unilateral renal stones, and 90 cases with double kidney stones. 104 cases were placed with double J tube before operation and 496 cases were not placed before operation. There were 8 cases of horseshoe kidney, 30 cases of isolated kidney with renal insufficiency, 4 cases of pelvic ectopic kidney with dysplasia, 6 cases of congenital ureteral malformation and 2 cases of sponge kidney. Preoperative average hemoglobin was (133.2±5.6)g/L, ranging 126-188 g/L.And average serum creatinine was (84.4±12.2)μmol/L, ranging 74-242μmol/L before operation. All patients were treated with general anesthesia under the lithotomy position. The ureteroscopy combined with holmium laser lithotripsy was performed.The 200μm fiber was used, which the parameters were set as 12-45 W(0.5-1.5 J/10-30 Hz). The stone baskets were used to take stones according to actual conditions. The operation was performed by doctors of the same qualifications. Results All patients underwent successful operation. The mean operation time was (45.6±14.6)min. The average postoperative hospitalization was (4.8±1.5)d. The postoperative serious complication rate was 0.9%, including(2 cases of sepsis and 1 case of subcapsular hematoma. Of the 640 patients, 596 were admitted to the hospital for a double J tube and 44 were lost of follow-up. 552 patients met the stone removal criteria, 44 patients did not meet the stone removal criteria for other treatments, such as extracorporeal shock wave lithotripsy, ureteroscopy or observed regularly. The stone-free rate (SFR) was 92.6% (552/596) after 1-3 months. On the first postoperative day, serum creatinine was (76.0±10.6)(58-156) μmol/L, and postoperative hemoglobin was (126.4±9. 6)(120-176) g/L. There was no significant difference in preoperative and postoperative hemoglobin (t=2.02, P=0.064). Preoperative and postoperative creatinine (t=64.76, P<0.05) was statistically significant. Meanwhile, the stone size (χ2=29.569, P<0.05) and position (χ2=44.949, P<0.05) versus SFR the impact was statistically significant. Multivariate regression analysis showed that stone size was not an independent risk factor for stone clearance (P=0.639). The stone position was an independent risk factor for stone clearance (P=0.013). Conclusions RIRS is a reliable treatment for small and medium calculi patients of the upper urinary tract. The curative effect of stone removal is clear, the complications are few, the safety is high. However, there are certain limitations to the efficacy in the treatment of large stones and lower calculi. Lower calculi is the independent risk factor for the treatment of efficacy. Key words: Ureteroscopes; Flexible ureteroscopy; Holmium laser lithotripsy; Upper urinary calculi; Clinical efficacy