Objective To investigate the efficacy and safety,as well as surgical essentials of upper urinary tract calculi (calculi being≤2 cm in diameter) complicated with pre-surgical uncertain pyonephrosis through one-stage renal calculi removal by percutaneous nephrolithotomy and suction device.Methods Retrospective analysis was used to detect the thirty-three cases with upper urinary tract calculi complicated with pre-surgical uncertain pyonephrosis collected from August 2010 to March 2016 in Yellow River Sanmenxia Hospital Affiliated to Henan University of Science and Technology,all the cases in the group had no pre-surgical fever,no apparent infection by blood-urine routine test,different degrees of hydronephrosis and no indications of pyonephrosis confirmed by CT and color Doppler ultrasonography,no pre-surgical anti-infection cure,pyonephrosis was found during the operation.First of all,a suction device was used to suck pus through percutaneous renal channel,rinsing repeatedly with small amount of fluid until the sucked rinsing fluid was clear;then,the one-stage calculi was removed by percutaneous renal lithotripsy,and the pus was sent to be cultured during the surgery,and the cases were treated by postoperative intravenous anti-infection for seven to seventeen days.Operation condition,postoperative blood routine,temperature,calculi removal and other clinical recovery conditions should be carefully observed.Results All the 33 cases underwent the one-stage single channel percutaneous nephrolithotom,the surgery was successful,the operation lasted 28-59 minutes,with an average of 41 minutes per case.Within the first-week of operation,CT reexamination showed the stone-free rate was 90.9% (30/33),and three cases had residual stone,the maximum diameter was about 6mm;seven cases had high fever within 3 days after the surgery (21.2%),and the temperature in four cases was higher than 38.5℃(12.1%) and two cases had fever within 3-6 days after surgery (6.1%),the highest temperature reached 38.0℃,and no fever existed after 6 days.Compared with preoperative values,the postoperative blood routine indicated that the surgery-relevant hemoglobin has decreased to (6.16±5.21) g/L;three days after surgery,white blood cell count was (7.16±4.86) 109/L.There were no severe complications such as sepsis,septic shock,renal abscess,hemorrhage.All cases were followed up for 6 to 36 months and no secondary pyonephrosis or renal dysfunction occurred during that period.Conclusion The treatment of upper urinary tract calculi,complicated with pyonephrosis without pre-surgical fever through one-stage renal calculi removal by percutaneous nephrolithotomy and suction device is effective and safe,it can be used as the routine method in basic hospitals and more attention should be paid to the operation and renal pelvic pressure in order to avoid the occurrence of complication.