Objective      To investigate the effect of different indwelling time and removal methods for double-pigtail stent after percutaneous nephrolithotomy (PCNL).       Methods      Eighty-four patients with upper urinary tract lithiasis were randomly divided into three groups including a long-time group (double-pigtail stent indwelled for 4 to 6 weeks and removed with conventional method under cystoscope

n=28)

a short-time group (double-pigtail stent indwelled for 8 to 12 d and removed with conventional method under cystoscope

n=28)

and an improved short-time group (double-pigtail stent indwelled for 8 to 12 d and removed with improved method through renal tract). All of the patients received questionnaire survey after removal of double-pigtail stent and discharge. The renal function and diuresis renogram of the patients were reexamined at 1 month after operation.       Results      The incidences of the complications after removal of double-pigtail stent including urethralgia

gross hematuria

urethral injury

irritation symptoms of bladder

urinary infection and fever in the improved short-time group were significantly lower than those in the long-time group and the short-time group (P0.05)

but the differences between the long-time group and the short-time group were not significant (P0.05). The incidences of the complications after discharge including gross hematuria

lumbar distending pain

irritation symptoms of bladder

urinary infection

fever

double-pigtail stent migration and vesicoureteric reflux in the long-time group were significantly higher than those in the short-time group and the improved short-time group (P0.05)

but the differences between the improved short-time and the short-time group were not significant (P0.05). The reexamination showed no significant differences of renal function and diuresis renogram among the three groups.       Conclusion      The application of improved removal method after 8-12 d PCNL should be recommended for its short indwelling time

low cost and few complications.