***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: PURPOSE A prospect i ve r and omized controlled trial was performed to determine whether stents may be eliminated after uncomplicated ureteroscopic lithotripsy for ureteral stones . MATERIAL S AND METHODS A total of 58 patients underwent uncomplicated ureteroscopic intracorporeal lithotripsy .  After stone fragmentation patients were r and omized to a  nonstented ( 29 ) or a stented ( 29 ) treatment group .  Intracorporeal lithotripsy was performed with the holmium laser in 57 cases and by electrohydraulic lithotripsy in 1 without balloon dilation or the extraction of stone fragments . Patients were followed 1 , 6 and 12 weeks postoperatively . In stented cases the stent was removed at 1 week . Outcome measures included postoperative symptoms assessed with a visual analog scale , postoperative analgesic requirements , complications and the stone-free rate . RESULTS At 1 week the symptoms of flank pain , abdominal pain , dysuria and frequency were significantly greater in the stented group ( p < 0.005 ) . There were no differences in symptoms in the groups at subsequent followup visits . There was no difference in treatment groups in terms of the amount of analgesic required in the recovery room or during 1 week after ureteroscopy . Similarly there was no difference in the number of patients requiring antiemetics . One patient in the stented group required hospitalization for genitourinary sepsis and 1 patient in the nonstented group visited the emergency room for postoperative vomiting . The stone-free rate was 100 % in each group . CONCLUSIONS These results demonstrate that after ureteroscopic intracorporeal lithotripsy with the holmium laser patients with a stent have significantly greater irritative and painful symptoms than those without a stent in the early postoperative period . There was no difference in nonstented and stented ureteroscopy with respect to complications or stone-free status . Therefore , we believe that routine stenting after ureteroscopic intracorporeal lithotripsy with the holmium laser is not required as long as the procedure is uncomplicated and performed without balloon dilation of the ureteral orifice Purpose To determine the need for pre-treatment stenting in patients undergoing extracorporeal shockwave lithotripsy ( ESWL ) for ureteral stones sized 4–10 mm . Methods A prospect i ve r and omized study was conducted between September 2009 and March 2011 . Included 156 patients r and omized in stented and non-stented groups and underwent a maximum of 3 ESWL sessions . Radiographic follow-up was used to assess the stone fragmentation and clearance . Results were compared in terms of stone-free rates , post-treatment morbidity and complications . Results Overall efficacy was 76.9 % . Stone-free rates were statistically significantly lower ( P = 0.026 ) in the stented group ( 68.6 % ) compared to the non-stented ones ( 83.7 % ) . Furthermore , stenting was significantly correlated with post-treatment lower urinary tract symptoms ( P ≤ 0.001 ) , need for more ESWL sessions ( P = 0.019 ) and possibility for operation due to ESWL failure ( P = 0.026 ) . A multivariate analysis was conducted to identify the parameters which may predict complete stone removal after ESWL . Stone size ( P = 0.026 ) , stone location ( P = 0.011 ) and stenting ( P = 0.007 ) were the most significant factors . Conclusions ESWL is an efficient and safe treatment for 4- to 10-mm ureteral stones . Pre-treatment stenting is limiting stone-free rates and is significantly influencing post-ESWL morbidity and quality of life in a negative manner , while it contributes minimally to the prophylaxis of complications BACKGROUND AND PURPOSE Insertion of a ureteral stent is routinely done after ureteroscopy . Recently , several authors have question ed routine stenting after ureteroscopy for distal ureteral stones . We report our results of a r and omized study comparing ureteroscopy with and without placement of stents for distal ureteral stones . PATIENTS AND METHODS A total of 48 patients undergoing ureteroscopy for distal ureteral stones were r and omized to a stented group ( N = 26 ) or a nonstented group  ( N = 22 ) . Ureteroscopy was carried out with Wolf 8.5F semirigid endoscope , and the Swiss Lithoclast was used as the source of energy . Any stent was removed at 3 weeks . Patients were assessed for success , operative time , postoperative pain score , analgesic requirement , stent-related symptoms , and risk of ureteral stricture formation . Baseline variables were not significantly different in the two groups . RESULTS There was no significant difference in the two treatment groups with regard to need for ureteral dilation , use of intracorporeal lithotripsy , or occurrence of intraoperative and postoperative complications . A successful outcome was achieved in 100 % of both groups . The mean pain score on day 0 was 5.23 + /- 0.95 of 10 in the stented group and 4.82 + /- 0.96 in the nonstented group ; this difference was not statistically significant . Similarly , the analgesic requirement in the two treatment groups was not significantly different . However , patients with stents had significantly more pain ( including flank pain with voiding : P = 0.01 ) , urgency ( P = 0.04 ) and dysuria ( P < 0.01 ) . Radiologic follow-up was available for 83.33 % of the patients at the 3-month visit . None of the patients had evidence of ureteral stricture or residual stone fragments . CONCLUSION In select patients undergoing ureteroscopy for distal ureteral stones , stents can be safely omitted . Patients without stents have significantly fewer lower-urinary symptoms of pain , urgency , and dysuria and are not at risk of increased complications . Avoiding stents may be particularly cost effective in developing countries PURPOSE We performed a prospect i ve , r and omized clinical trial to evaluate the outcome of ureteral stents for solitary ureteral stones 2 cm or less in moderately or severely obstructed systems using shock wave lithotripsy . MATERIAL S AND METHODS Between 2001 and 2004 , 186 patients who met study criteria were r and omized into 2 groups . Group 1 received a pre-shock wave lithotripsy 6Fr Double-J stent and group 2 had no stent . Patients were treated with a Dornier MFL 5000 lithotripter . Results were compared in terms of clearance rates , number of shock waves and sessions , irritative voiding symptoms , incidence of complications and secondary interventions . Failure was defined as the need for additional procedure(s ) for stone extraction . RESULTS Overall 164 patients ( 88.2 % ) became stone-free after shock wave lithotripsy . Complete stone fragmentation was achieved after 1 to 3 and more than 3 session in 108 ( 58.1 % ) , 30 ( 16.1 % ) , 13 ( 7 % ) and 14 patients ( 7.5 % ) , respectively . Ureteral stent insertion did not affect the stone-free rate , which was 84.9 % and 91.4 % in groups 1 and 2 , respectively ( p = 0.25 ) . There was no statistical difference in the re-treatment rate , flank pain or temperature in the 2 groups . However , all patients in the stented group significantly complained of side effects attributable to the stent , including dysuria , suprapubic pain , hematuria , pyuria and positive urinary culture . CONCLUSIONS Pretreatment stenting provides no advantage over in situ shock wave lithotripsy for significantly obstructing ureteral calculi . Shock wave lithotripsy is reasonable initial therapy for ureteral stones 2 cm or less that cause moderate or severe hydronephrosis PURPOSE We determined the differences in outcome between ureteral stenting and nonstenting following uncomplicated ureteroscopy for distal ureteral stones . MATERIAL S AND METHODS A total of 220 patients treated with successful ureteroscopy for distal ureteral stones were r and omized to 2 equal groups according to postoperative placement of a ureteral stent ( Cook Irel and , National Technological Park , Irel and ) , including group 1 - -without a stent and group 2 - -with a stent . Outcome measures were flank pain and dysuria at 48 hours and 1 week , early postoperative complications , analgesia need , rehospitalization , return to normal physical activity , stone-free rate , stone recurrence and late postoperative complications .  Patients were followed a mean + /- SD of 25 + /- 9 months ( range 12 to 49 ) . RESULTS Early postoperative complications , including low grade fever , hematuria and urinary tract infection , were observed in 22 patients ( 20 % ) in group 1 and 19 ( 19 % ) in group 2 , a difference of no significant value . Mean initial hospitalization and time to return to normal physical activity were not different between the 2 groups . At 48 hours and 1 week there was no significant difference in flank pain between the 2 groups , while dysuria was significantly less in the nonstented group . The amount of analgesics required in the recovery room was not different but after discharge from the hospital stented patients used a larger amount of analgesia while the stent was still in the ureter . The stone-free rate at 4 weeks was 100 % in each group . Late postoperative sequelae , including stone recurrence and ureteral narrowing , were reported in 6 patients ( 5.5 % ) in group 1 and 4 ( 3.6 % ) in group 2 , a difference of no significant value . CONCLUSIONS Uncomplicated ureteroscopy for treatment of distal ureteral stones is safe without stent placement . Patients without stents have significantly fewer irritative bladder symptoms and are not at risk of increased complications BACKGROUND AND PURPOSE Ureteral stent placement after ureteroscopic lithotripsy has some advantages and disadvantages . In this r and omized study , the necessity of ureteral stent placement after uncomplicated ureteroscopy for impacted ureteral stones was assessed . MATERIAL S AND METHODS Between 2005 and 2007 , 60 evaluable patients were equally r and omized to groups  with and without stents . Patients underwent ureteroscopic pneumatic lithotripsy for ureteral stones . The operation was completed with or without stent placement according to the r and omization order . Excretory urography was performed 3 months after the procedure . All stents were cystoscopically removed at the third postoperative week . Sociodemographic and clinical variables ( age , sex , stone location , stone size , operative time , hospital stay , narcotic and nonnarcotic analgesic use ) , and postoperative complications ( fever , pain delaying discharge , emergency department visit , urinary retention , stent-related irritative symptoms ) were evaluated . RESULTS Mean stone size was not significantly different in both groups . Mean operative time was significantly longer in the stent group : 30.5 + /- 9.6 vs 43.7 + /- 11.6 minutes . On the operation day and until postoperative day ( POD ) 5 , narcotic ( P = 0.004 ) and nonnarcotic analgesic ( P = not significant ) use was more frequent in the no-stent group . At POD 5 and later , although narcotic and nonnarcotic analgesic use were frequently necessary in the stent group , both were almost unnecessary in the no-stent patients . Stent-related irritative symptoms were overwhelmingly higher ( 10 % vs 93 % ) in the stent group . Discharge was delayed ( 23 % vs 10 % ) and unplanned emergency department visits ( 20 % vs 10 % ) were exercised almost two times more commonly in the no-stent group . Stone-free rates were identical ( n = 29/30 ; 97 % ) in both groups . CONCLUSION Routine placement of a ureteral stent is not m and atory in patients without complications after ureteroscopic lithotripsy for impacted ureteral stones . Stent placement can be argued and agreed with the patients preoperatively in the light of the data presented above OBJECTIVE To verify if post-ureteroscopy ( URS ) stenting is still necessary as a routine strategy , or if some cases can be treated without . METHODS Between August 2004 and April 2005 , 85 patients were admitted to the Urology Department at the Nephrology and Urology Center , Al-Thawra Hospital , Yemen with ureteric stones of different size and site . All were scheduled and treated by the ureteroscopy method .  According to prospect i ve pure r and omization , 45 patients were left non-stented  at the end of the operation ( non-stented group ) , while 40 patients were left with stent ( stented group ) . RESULTS The ages of the non-stented group ranged between 6 - 70 years ( mean 34.36 + /- 15.53 ) , while the size of the stones ranged between 5 - 20 mm ( mean 8.4 + /- 3.1 ) . They were 33 males and 12 females . Regarding the site , 
    Output:
    
Our analysis showed that stenting failed to improve the stone-free rate , and instead , it result ed in additional complications .
However , ureteral stents are valuable in preventing unplanned re-hospitalization .