Percutaneous nephrolithotripsy is the first line treatment for complete staghorn calculi, but there are risks such as renal function damage, bleeding, and infection. A case of complete staghorn calculi 8.3 cm×4.5 cm and mean CT value of 1 321 HU was reported. Urine culture suggested proteus mirabilis infection. The patient was given sensitive antibiotics for 3 days, and was treated with one session of natural orifice transluminal endoscopic lithotripsy with intelligent control of renal pelvic pressure. KUB on the first postoperative day showed residual stones of 1.0 cm×0.5 cm. There were no complications.

Objective To evaluate the efficacy and safety of suctioning flexible ureteroscopy with automatic control of renal pelvic pressure in the treament of intrarenal and proximal ureteral stones.Methods From November 2014 to December 2016,a total of 372 patients,including 200 males and 172 females,with upper urinary tract calculi were studied.The average age of patients was 48.1 years old.The average size of stone was 5-35mm,mean 15.7mm.There were 272 cases of renal calculi,80 cases of ureteral calculi and 20 cases of renal calculi combined with ureteral calculi.There were 252 cases of single calculi and 127 cases of multiple calculi.There were 237 cases of urinary tract infection and 14 cases of bacteremia.All patients were treated by suctioning fiexible uretemscopy with automatic control of renal pelvic pressure by a patented intelligent system including an irrigation and suctioning platform and a ureteral access sheath with a pressuresensitive tip.Statistical analysis was performed regarding renal pelvic pressure,operative time,stone-free rates,and complications.Results Three hundred and thirty of 372 patients only accepted one surgery to remove the stone.There were 12 cases of upper ureteral calculi were converted to ureteroscope lithotripsy.Seventeen cases were converted to percutaneous nephrolithotomy due to significant ureteral stenosis.Seven cases who failed the first surgery due to difficulty in placing the ureteral access sheath but flexible ureteroscopy were successfully performed in these patients after indwelling a D-J stent for 2 weeks.No stone was found in 6 cases,and the soft endoscope of ureter was examined.In all patients,the renal pelvic pressure of the pelvis was controlled within 20 mmHg.The average operative time was 15-180 min(mean 58.9 min).The stone-free rates was 95.55％ (322/337),the incidence of postoperative fever was 2.97％ (10/337),the sepsis rate was 1.19％ (4/337),the incidence of urinary sepsis was 0.89％ (3/337),the incidence of lumbago caused by extravasation was 0.59％ (2/337),and no peripheral viscera injury or death case.There was no statistically significant difference between preoperative and postoperative white and red blood cells (P ＞ 0.05).Conclusions This new type of suctioning flexible ureteroscopy with intelligent pressure-control has the advantages of perfusion attraction,pressure feedback,intelligent control and visualization of intracavity pressure.It could be a new type of operation with high safety,low complication and high stone free rate.