Curr Urol Rep. 2018 Mar 17;19(5):29. doi: 10.1007/s11934-018-0782-3.

Asymptomatic Renal Stones-to Treat or Not to Treat.

Streeper NM1.



There are no current guidelines on the optimal management of asymptomatic renal stones. This review summarizes the current literature, focusing on more recent studies that have been done to grow the body of evidence on this topic.


Recent studies have found that stone size is a significant predictor of need for future surgical intervention, with > 7 mm for pediatric population and > 4 mm for residual fragments after both PNL and ureteroscopy (URS). The role of URS has been better defined with a recent RCT concluding that URS and SWL had comparable outcomes for an asymptomatic lower pole stone < 1 cm. The treatment decision for asymptomatic renal stones should take into consideration a variety of relevant patient and stone factors; however, ultimately, a shared decision-making approach should be used. In the properly counseled patient, active surveillance or prophylactic surgical intervention may be appropriate.


Asymptomatic; Observation; Renal stones; Residual fragments; Treatment

PMID: 29550897 DOI: 10.1007/s11934-018-0782-3

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World J Urol. 2018 Mar 13. doi: 10.1007/s00345-018-2258-y. [Epub ahead of print]

Comparative study of the treatment of 20-30 mm renal stones with miniaturized percutaneous nephrolithotomy and flexible ureterorenoscopy in obese patients.

Chen HQ1, Chen ZY1, Zeng F1, Li Y1, Yang ZQ1, He C1, He Y2.



To evaluate and compare flexible ureteroscopy (f-URS) and mini-percutaneous nephrolithotomy (mPNL) for 20-30 mm renal stones in obese patients regarding efficacy and safety.


Between May 2011 and June 2017, 254 obese patients who had 20-30 mm kidney stone were consecutively included in the study; 106 patients underwent mPNL and 148 underwent f-URS by the same surgeon. The following parameters were retrospectively assessed: patient and stone characteristics, surgical details, perioperative outcomes, and stone-free rates (SFR).


F-URS group was similar to mPNL group in terms of the mean duration of surgery (92.8 ± 26.1 vs 87.4 ± 31.5 min, P = 0.137) and the final SFR (89.1 vs 92.5%, P = 0.381). The f-URS group had significantly shorter postoperative stay (1.0 ± 0.8 vs 4.3 ± 1.7 days, P < 0.001) and lower postoperative complications (11.5 vs 26.4%, P = 0.002). However, the f-URS group had a lower SFR after first session (67.2 vs 87.4%, P < 0.001) and needed more number of procedures (1.5 ± 0.4 vs 1.3 ± 0.4, P < 0.001) than the mPNL group.


MPNL has a higher efficacy (higher SFR after first session and lower number of procedures); however, f-URS offers advantages regarding safety (lower complication rate). Therefore, both options can be offered to obese patients with renal stones from 20 to 30 mm in size. Nevertheless, these results must be confirmed by further prospective randomized trials.


F-URS; MPNL; Obese; Renal stones; Size

PMID: 29536158 DOI: 10.1007/s00345-018-2258-y

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Scand J Urol. 2018 Feb 20:1-6. doi: 10.1080/21681805.2018.1437770. [Epub ahead of print]

Effects of flexible ureteroscopy on renal blood flow: a prospective evaluation.

Sener TE1, Tanidir Y1, Bin Hamri S2, Sever IH3, Ozdemir B3, Al-Humam A2, Traxer O4.



This study aimed to investigate the effects of flexible ureteroscopy (F-URS) on renal blood flow using renal Doppler ultrasound (US).


Patients undergoing F-URS were scheduled for Doppler US preoperatively and postoperatively. Peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index (RI) and pulsatility index (PI) were reported. Technical details, operation time, stone characteristics and complications were recorded. Patients were grouped as 9.5/11.5-Flex-X2, 10/12-Flex-X2, 10/12-Flex-XC, 12/14-Flex-X2 and 12/14-Flex-XC, with 28, six, three, seven and two patients in each group, respectively.


Forty-six patients with a mean age of 41.24 years and stone volume of 1685 mm³ were enrolled. The PSV, EDV, PI and RI of renal arteries in all groups in preoperative and postoperative periods were similar. Arcuate artery measurements in all groups were also similar in preoperative and postoperative periods, without any significant difference except in two parameters: RI in the 9.5/11.5-Flex-X2 group and PSV in the 12/14-Flex-X2 group. The resistive index in the arcuate artery of the 9.5/11.5-Flex-X2 group was increased from 0.59 to 0.62 cm/sec postoperatively. The PSV in the arcuate artery of the 12/14-Flex-X2 group was decreased from 30.9 to 27.2 cm/sec. Three patients had urinary tract infections postoperatively and two had sepsis.


This study suggests that compatible ureteroscope-ureteral access sheath combinations with a lumen difference of more than 1.5 Fr can provide safe outcomes in terms of renal blood flow. F-URS can safely be performed in terms of renal perfusion and complication rates with appropriate equipment and instruments.


Renal blood flow; ultrasonography; ureteroscopy

PMID: 29463207 DOI: 10.1080/21681805.2018.1437770

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Eur Urol. 2017 Nov 23. pii: S0302-2838(17)30986-7. doi: 10.1016/j.eururo.2017.11.010. [Epub ahead of print]

Medical Expulsive Therapy for Distal Ureteral Stones: The Verdict is In.

Dahm P1, Sukumar S2, Hollingsworth JM3.


In the setting of stone disease, one of the most heated debates in recent years has been on the value of medical expulsive therapy (MET) using α-blockers (ABs) in patients with ureteric stones. MET first gained acceptance in the medical community following a systematic review (SR) and meta-analysis that summarized nine small trials of limited methodological quality [1]. The study suggested a >50% higher risk of spontaneous stone passage associated with AB use, equating to a number-needed-to-treat (NNT) of four.

PMID: 29174467 DOI: 10.1016/j.eururo.2017.11.010

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Urolithiasis. 2018 Mar 16. doi: 10.1007/s00240-018-1055-9. [Epub ahead of print]

Mini vs standard percutaneous nephrolithotomy for renal stones: a comparative study.

ElSheemy MS1, Elmarakbi AA2, Hytham M3, Ibrahim H4, Khadgi S5, Al-Kandari AM6.


To compare the outcome of mini-percutaneous nephrolithotomy (Mini-PNL) versus standard-PNL for renal stones. Retrospective study was performed between March 2010 and May 2013 for patients treated by Mini-PNL or standard-PNL through 18 and 30 Fr tracts, respectively, using pneumatic lithotripsy. Semirigid ureteroscope (8.5/11.5 Fr) was used for Mini-PNL and 24 Fr nephroscope for standard-PNL. Both groups were compared in stone free rate(SFR), complications and operative time using Student-t, Mann-Whitney, Chi square or Fisher’s exact tests as appropriate in addition to logistic regression analysis. P < 0.05 was considered statistically significant. Mini-PNL (378) and standard-PNL (151) were nearly comparable in patients and stones criteria including stone burden (3.77 ± 2.21 vs 3.77 ± 2.43 cm2; respectively). There was no significant difference in number of tracts or supracostal puncture. Mini-PNL had longer operative time (68.6 ± 29.09 vs 60.49 ± 11.38 min; p = 0.434), significantly shorter hospital stay (2.43 ± 1.46 vs 4.29 ± 1.28 days) and significantly higher rate of tubeless PNL (75.1 vs 4.6%). Complications were significantly higher in standard-PNL (7.9 vs 20.5%; p < 0.001). SFR was significantly lower in Mini-PNL (89.9 vs 96%; p = 0.022). This significant difference was found with multiple stones and large stone burden (> 2 cm2), but the SFR was comparable between both groups with single stone or stone burden ≤ 2 cm. Logistic regression analysis confirmed significantly higher complications and SFR with standard-PNL but with significantly shorter operative time. Mini-PNL has significantly lower SFR when compared to standard-PNL (but clinically comparable) with markedly reduced complications and hospital stay. Most of cases can be performed tubeless. The significant difference in SFR was found with multiple stones or large stone burden (> 2 cm2), but not with single stones or stone burden ≤ 2 cm2.


Mini-PNL; Mini-percutaneous nephrolithotomy; Miniperc; Percutaneous nephrolithotomy; Renal stones

PMID: 29549382 DOI: 10.1007/s00240-018-1055-9

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Urolithiasis. 2018 Feb 26. doi: 10.1007/s00240-018-1051-0. [Epub ahead of print]

Results of minimally invasive surgical treatment of allograft lithiasis in live-donor renal transplant recipients: a single-center experience of 3758 renal transplantations.

Sarier M1,2, Duman I3, Yuksel Y4, Tekin S5, Demir M6, Arslan F4, Ergun O7, Kosar A7, Yavuz AH8.


Allograft lithiasis is a rare urologic complication of renal transplantation (RT). Our aim is to present our experience with minimally invasive surgical treatment of allograft lithiasis in our series of live-donor renal transplant recipients. In a retrospective analysis of 3758 consecutive live-donor RTs performed in our center between November 2009 and January 2017, the results of minimally invasive surgery for the treatment of renal graft lithiasis diagnosed at follow-up were evaluated. Twenty-two (0.58%) patients underwent minimally invasive surgery for renal graft lithiasis. The mean age was 41.6 years, and duration between RT and surgical intervention was 27.3 months (range 3-67). The mean stone size was 11.6 mm (range 4-29). Stones were located in the urethra in 1, bladder in 2, ureter in 9, renal pelvis in 7 and calices in 3 patients. Surgical treatment included percutaneous nephrolithotomy in 1, cystoscopic lithotripsy in 3, flexible ureteroscopic lithotripsy in 6 and rigid ureteroscopic lithotripsy in 12 patients. No major complications were observed. One patient (4.5%) who underwent flexible ureteroscopy developed postoperative urinary tract infection. All patients were stone-free except two (9%) patients who required a second-look procedure after flexible ureteroscopic lithotripsy for residual stones. Stone recurrence was not observed in any patient during a mean follow-up duration of 30.2 months (range 8-84). Renal transplant lithiasis is uncommon and minimally invasive surgical treatment is rarely performed for its treatment. Endourological surgery may be performed safely, effectively and with a high success rate in these patients.


Renal transplantation; Ureteroscopy; Urolithiasis

PMID: 29484468 DOI: 10.1007/s00240-018-1051-0