Current minimally invasive management options for upper urinary tract stones include URS and PCNL [2, 3]. Although ureteroscopic stone removal procedures are being preferred mainly for medium sized stones (1–2 cm), PCNL is the treatment of choice for the successful treatment of large (> 2 cm) stones. Related with this issue, technological developments and new concepts have expanded the indications for URS with retrograde effective use of flexible scopes/ suction facilities and for PCNL with miniaturization of the equipments used [2, 3]. Although both modalities are being performed in all parts of the world with successful outcomes in experienced hands, they are not completely safe where some possible well-known complications could occur at every step but particularly during post-operative period after these procedures [4,5,6,7,8,9,10].

Infection related complications are the most critical issue to be kept in mind prior to these minimal invasive procedures particularly before/during retrograde intrarenal manipulations. Although flexible ureteroscopic renal stone removal has become a valuable alternative on this aspect, application of the procedure for larger stones with acceptable stone free rates may increase the risk of such complications [3, 4].Accumulated experience and published data indicate that such complications (which sometimes could be lethal) need to be kept in mind with a very careful/rational treatment plan [8, 9, 11]. Infective problems after fURS procedures include post-operative fever occuring in 7.1%, UTI in 8.1% and sepsis in 5.4% of the cases managed [7,8,9,10]. In addition such infective complication could be encountered in 0.9–16.7% of the cases after percutaneous stone removal procedures [7,8,9,10,11,12,13,14,15].

In the light of these facts, to prevent such problems which could even be lethal in some cases, a rational and careful pre-operative diagnostic approach seems to be highly critical [24].The presence of any UTI should be well evaluated and treated prior to such interventions [16, 17, 20]. A systemic review showed that a urine culture test is superior to simple urine analysis test in ruling out bacteriuria and should therefore be performed in every candidate with symptoms of infection prior to endoscopic stone removal procedures [20].However, a negative urine dipstick test has also been found to be effective and predictive as a screening test with this aim [21].

In other words, it seems to be sufficient obtaining a pre-operative urine culture only in case of a positive urine analysis test regarding the measures to be taken for post-operative infective complications. In accordance to the recommendations of the EAU and the AUA, all patients need to receive an intraoperative single-shot antibiotic prophylaxis [5, 6, 10];except patients, who already received a sensitivity test-guided pre-operative antibiotic treatment based on a significant bacterial growth (≥ 10E5 CFU/ml) in urine culture. The systemic review and metanalysis of Lo et al. showed that a prophylactic antibiotic treatment can reduce the incidence of pyuria and bacteriuria following ureterorenoscopic laser lithotripsy, but not the incidence of clinically relevant UTI [16]. On the contrary, Gravas et al. showed, that patients undergoing PCNL without perioperative antibiotic prophylaxis had a significant higher rate of fever (p = 0.04) and complications within the first 30 days (< 0.0001) of post-operative period compared to patients undergoing antibiotic prophylaxis [18].

Thus, a well planned, rational decision making (evaluating the stone and patient related factors) along with a thorough urine examination seem to be the most crucial factors for safe and successful outcomes. In an attempt to limit or prevent such infective complications which may sometimes cause death after such endoscopic stone removal procedures, every candidate patient should be well evaluated for the presence and severity of UTI. Following the performance of a mid-stream urine culture and sensitivity test in case of a documented infection, UTI should inevitably be treated to render the patient infection free prior to such procedures. It is appropriate to obtain a urine culture for every patient where the presence of leucocytes and/or nitrite may be regarded as reliable indicators for a UTI. Related with this issue, the EAU recommends to perform a urinary microscopy and/or obtaining a urine culture before stone removal interventions for an effective antibiotic management [6]. However, both EAU and AUA guidelines acknowledge that their recommendations for antibiotic prophylaxis are based on limited evidence regarding the choice of antimicrobial agents, dose, timing, and duration of procedure [5, 6, 10].

On the other hand, no distinct data has been reported to date to emphasize the necessity of a perioperative antibioticprophylaxis for URS and this approach is being recommended by EAU guidelines to every patient undergoing endourological treatmentexcept simple diagnostic URS and distal ureteral stone treatment [16, 17]. Although the necessity and the effectivity of perioperative antibiotic prophylaxis were well evaluated in a limited number of studies so far with varying rate of success and degree of recommendations [18, 19], EAU guidelines state that, few studies could be derived from published literature defining the risk of infection following URS and percutaneous stone removal with no clear-cut evidence.

These findings emphasize that a careful evaluation regarding the presence of UTI and an appropriate management based on the culture sensitivity test outcomes seems to be highly critical before such interventions. With this rational approach, the likelihood of post-operative infection could be limited to a certain extent in such cases. A systematic review demonstrated that performance of a urine culture/sensitivity test is superior to a simple urinalysis in ruling out any infection and therefore this approach should be the standard in all patients[20]. However, although EAU guidelines recommend this approach; the exact need for an additional urine culture test after completion of antibiotic regimen before planned stone removal procedure to confirm the presence of a negative urine culture is not fully outlined with clinical evidence.

Evaluation of our findings showed no statistically significant difference regarding the rate of infective complications (presence of fever, incidence of septic findings), duration of hospitalization and readmission rates between two group of cases. Although the presence of a negative urine culture has been confirmed by urine culture test in group 1 cases, no additional urine culture was performed in group 2 cases (sterile urine was confirmed with only urinalysis) and the outcomes regarding the infective problems were found to be similiar.

In the light of our results and ongoing debate regarding the necessity of performing a second urine culture test following a sensitivity based antibiotic treatment before planned procedures; this approach seems to obtain a challenging status. Based on present our findings, elimination of a second urine culture test could bring the diagnostic procedures in a simplified status by lowering the laboratory workload and limit the overall costs. To the best of our knowledge, this is the first study which will in turn give reliable insights into this ongoing, challenging issue. Morover, this will let the endourologist to perform the procedure without any delay waiting for the result of second culture test (earlier removal of the stone and related problems) and more importantly let the patient have diminished stress with a well preserved quality of life.

Our study is not free of limitations. First of all the retrospective nature of the design is an important one and the number of cases included could be accepted as relatively small. However taking the highly limited data reported so far on this very critical issue into account, we believe that as the first trial focusing on this issue our data will be contributive enough on this aspect.