Tag Archive for: lithotripsy


Article of the week: Ultrasound guidance can be used safely for renal tract dilatation during percutaneous nephrolithotomy

Every week, the Editor-in-Chief selects an Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

In addition to the article itself, there is an editorial written by a prominent member of the urological community and a visual abstract prepared by a trainee urologist; we invite you to use the comment tools at the bottom of each post to join the conversation. 

If you only have time to read one article this week, we recommend this one. 

Ultrasound guidance can be used safely for renal tract dilatation during percutaneous nephrolithotomy

Manuel Armas-Phan*, David T. Tzou*, David B. Bayne*, Scott V. Wiener*, Marshall L. Stoller* and Thomas Chi*

*Department of Urology, University of California, San Francisco, CA and Division of Urology, University of Arizona, Tucson, AZ, USA



To compare clinical outcomes in patients who underwent percutaneous nephrolithotomy (PCNL) with renal tract dilatation performed under fluoroscopic guidance vs renal tract dilatation with ultrasound guidance.

Patients and Methods

We conducted a prospective observational cohort study, enrolling successive patients undergoing PCNL between July 2015 and March 2018. Included in this retrospective analysis were cases where the renal puncture was successfully obtained with ultrasound guidance. Cases were then grouped according to whether fluoroscopy was used to guide renal tract dilatation or not. All statistical analyses were performed using Stata version 15.1 including univariate (Fisher’s exact test, Welch’s t‐test) and multivariate analyses (binomial logistic regression, ordinal logistic regression, and linear regression).


A total of 176 patients underwent PCNL with successful ultrasonography‐guided renal puncture, of whom 38 and 138 underwent renal tract dilatation with fluoroscopic vs ultrasound guidance, respectively. There were no statistically significant differences in patient age, gender, body mass index (BMI), preoperative hydronephrosis, stone burden, procedure laterality, number of dilated tracts, and calyceal puncture location between the two groups. Among ultrasound tract dilatations, a higher proportion of patients were placed in the modified dorsal lithotomy position as opposed to prone, and a significantly shorter operating time was observed. Only modified dorsal lithotomy position remained statistically significant after multivariate regression. There were no statistically significant differences in postoperative stone clearance, complication rate, or intra‐operative estimated blood loss. A 5‐unit increase in a patient’s BMI was associated with 30% greater odds of increasingly severe Clavien–Dindo complications. A 5‐mm decrease in the preoperative stone burden was associated with 20% greater odds of stone‐free status. No variables predicted estimated blood loss with statistical significance.


Renal tract dilatation can be safely performed in the absence of fluoroscopic guidance. Compared to using fluoroscopy, the present study demonstrated that ultrasonography‐guided dilatations can be safely performed without higher complication or bleeding rates. This can be done using a variety of surgical positions, and future studies centred on improving dilatation techniques could be of impactful clinical value.

Editorial: Zero‐radiation stone treatment

In this month’s BJUI, Armas‐Phan et al. [1] report on a prospective observational trial of fluoroscopic vs ultrasound (US)‐guided tract dilatation during percutaneous nephrolithotomy (PCNL). A total of 176 patients underwent successful initial US‐only guided puncture; of these patients, 138 had US‐only dilatation, while in 38 fluoroscopy was required. The authors found no difference in patient factors (e.g. age, gender, body mass index [BMI]) or stone factors (hydronephrosis, stone burden, number of tracts or puncture location). On multivariate analysis, US dilatation was more likely to be performed in the modified dorsal lithotomy position (compared to prone), but there was no significant difference in important outcomes such as stone clearance, complication rates or blood loss.

Whilst only reporting on access (and not necessarily dilatation), the Clinical Research Office of the Endourological Society PCNL Global Study shows us that worldwide fluoroscopic access is by far the most common (88.3% of cases) [2] and there are relatively few reports of US‐guided dilatation in the literature. The technique does produce technical challenges as the surgeon needs to confidently identify the depth of the dilators or balloon and be sure of its location relative to calyceal anatomy. Whilst dilating short is not usually a problem as simply re‐dilating can be done, dilating too far carries serious risk of perforation of the pelvicalyceal system and vascular injury. The authors’ described technique does rely on good kidney and guidewire visualisation, and if this is not possible then fluoroscopy is used instead. Thus, even in this series with experts at this technique, 38 (22%) underwent fluoroscopic dilatation after US‐guided puncture, and of the 138 with intended US dilatation, seven (5%) were converted to fluoroscopy. Furthermore, 115 patients never entered this series as they underwent initial fluoroscopic‐guided puncture. Thus, it is important to realise that this is a series of select patients being treated by expert enthusiasts of this technique and fluoroscopy should be available in the operating theatre, as it is not possible to do this technique for all patients. In particular, obesity limits the visualisation under US and the authors have previously shown that renal access drops from 76.9% of normal‐weight patients (BMI <25 kg/m2) to 45.6% for those classified as obese (BMI >30 kg/m2) [3]. An alternative strategy to avoid radiation is to use endoscopic combined intrarenal surgery (ECIRS), as the depth of dilatation can be monitored by direct visualisation via the flexible ureteroscope.

Patients and healthcare professionals are increasingly aware of the risks posed by ionising radiation. Ferrandino et al. [4] analysed radiation exposure of patients presenting with acute stone episodes in an American setting. The mean dose was a staggering 29.7 mSv and 20% of patients received >50 mSV. There is also awareness of risk to the operating staff from endourological procedures and although doses are relatively low [5], these can accumulate during a lifetime of operating, with risks of not only malignancy but also cataract formation [6]. Whilst I am sure we all wear protective lead gowns in the operating theatre, how many people wear lead glasses? A recent study showed that, at typical workload, the annual dose to the lens of the eye was 29 mSv in interventional endourology [7].

As urologists, we should all be aware of these risks and follow the ALARA (As Low As Reasonably Achievable) principals of keeping doses to a minimum. Thus, this paper [1] is particularly welcome and shows zero‐radiation procedures can be safely performed. The authors now attempt this technique for all PCNL procedures and achieve US‐only puncture and dilatation in over half of their patients. Hopefully, this paper will inspire us all to look at reducing or eliminating radiation usage in our stone procedures and this will be good for patients and surgeons alike.

by Matt Bultitude



  1. Armas‐Phan MTzou DTBayne DB et al. Ultrasound guidance can be used safely for renal tract dilatation during percutaneous nephrolithotomy. BJUI 2019; 125: 284-91
  2. De La Rosette JAssimos DDesai M et al. The Clinical Research Office of the Endourological Society Percutaneous Nephrolithotomy Global Study: indications, complications, and outcomes in 5803 patients. J Endourol 20112511– 7
  3. Usawachintachit MMasic SChang HAllen IChi TUltrasound guidance to assist percutaneous nephrolithotomy reduces radiation exposure in obese patients. Urology 20169832– 8
  4. Ferrandino MNBagrodia APierre SA et al. Radiation exposure in the acute and short‐term management of urolithiasis at 2 academic centers. J Urol 2009181668– 72
  5. Galonnier FTraxer ORosec M et al. Surgical staff radiation protection during fluoroscopy‐guided urologic interventions. J Endourol 201630638– 43
  6. Hartmann JDistler FBaumuller M et al. Risk of radiation‐induced cataracts: investigation of radiation exposure to the eye lens during endourologic procedures. J Endourol 201832897– 903
  7. Hristova‐Popova JZagorska ASaltirov I et al. Risk of radiation exposure to medical staff involved in interventional endourology. Radiat Prot Dosimetry 2015165268– 71



Article of the Week: Antibiotic prophylaxis in ureteroscopic lithotripsy

Every Week, the Editor-in-Chief selects an Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

In addition to the article itself, there is an accompanying editorial written by a prominent member of the urological community. This blog is intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation.

If you only have time to read one article this week, it should be this one.

Antibiotic prophylaxis in ureteroscopic lithotripsy: a systematic review and meta‐analysis of comparative studies

Tuo Deng*†‡, Bing Liu§, Xiaolu Duan*†‡, Chao Cai*†‡, Zhijian Zhao*†‡, Wei Zhu*†‡Junhong Fan*†‡, Wenqi Wu*†‡ and Guohua Zeng*†‡


*Department of Urology, Minimally Invasive Surgery Center, The First Afliated Hospital of Guangzhou Medical University, Guangzhou, China, Guangzhou Institute of Urology, Guangzhou, China, Guangdong Key Laboratory of Urology, Guangzhou, China, and §The First Afliated Hospital of Jinan University, Guangzhou, China


Read the full article



To explore the efficacy of antibiotic prophylaxis and the different strategies used to prevent infection in ureteroscopic lithotripsy (URL) by conducting a systematic review and meta‐analysis.

Materials and Methods

A systematic literature search using Pubmed, Embase, Medline, the Cochrane Library, and the Chinese CBM, CNKI and VIP databases was performed to find comparative studies on the efficacy of different antibiotic prophylaxis strategies in URL for preventing postoperative infections. The last search was conducted on 25 June 2017. Summarized unadjusted odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the efficacy of different antibiotic prophylaxis strategies.


A total of 11 studies in 4 591 patients were included in this systematic review and meta‐analysis. No significant difference was found in the risk of postoperative febrile urinary tract infections (fUTIs) between groups with and without antibiotic prophylaxis (OR: 0.82, 95% CI 0.40–1.67; P = 0.59). Patients receiving a single dose of preoperative antibiotics had a significantly lower risk of pyuria (OR: 0.42, 95% CI 0.25–0.69; P = 0.0007) and bacteriuria (OR: 0.25, 95% CI 0.11–0.58; P = 0.001) than those who did not. Intravenous antibiotic prophylaxis was not superior to single‐dose oral antibiotic prophylaxis in reducing fUTI (OR: 1.00, 95% CI 0.26–3.88; P = 1.00).


We concluded that preoperative antibiotic prophylaxis did not lower the risk of postoperative fUTI, but a single dose could reduce the incidence of pyuria or bacteriuria. A single oral dose of preventive antibiotics is preferred because of its cost‐effectiveness. The efficacy of different types of antibiotics and other strategies could not be assessed in our meta‐analysis. Randomized controlled trials with a larger sample size and more rigorous study design are needed to validate these conclusions.

Read more articles of the week

Editorial: Antibiotics and ureteroscopy: a single prophylactic dose is enough, but could we give even less?

Antibiotic resistance is internationally recognized as a threat to global health. As a consequence, there is an ongoing need to review antibiotic prescribing practice, both for treatment and prophylaxis. ‘Antibiotic stewardship’, whereby antimicrobial use, and the associated increase in bacterial resistance, is reduced, is essential worldwide [1].

In this issue of BJUI, Deng et al. [2] present the results of their systematic review and meta‐analysis of the efficacy of antibiotic prophylaxis vs no treatment in patients undergoing upper tract ureteroscopy/ureterorenoscopy. In total, 4591 patients were analysed (from 11 studies, comprising five randomized controlled trials, one prospective comparative study and five retrospective comparative studies), of whom 2700 patients received antibiotic prophylaxis and the remaining 1891 had no prophylactic antibiotics at all. To know more visit walkerstgallery .

Having excluded patients with pre‐operative urinary tract infection (UTI) or bacteriuria, they found that patients who received a single dose of pre‐operative antibiotic had a significantly lower risk of pyuria and bacteriuria than those without antibiotic, but that there was no difference in the risk of post‐operative febrile UTIs between the groups with and without the use of prophylactic antibiotic. There was also no advantage to intravenous antibiotic administration compared with oral administration in reducing febrile UTIs, nor any difference between a single dose of antibiotic drug vs a more prolonged post‐operative regime [2].

This is an important article, potentially leading many urological surgeons to change their current practice with regard to prescribing post‐operative antibiotics, and raising the question of whether antibiotic prophylaxis is needed in patients who have sterile urine pre‐operatively and no specific operative risk factors.

The next question for endourologists to answer will be ‘What is the most appropriate management of asymptomatic bacteriuria detected during pre‐operative investigations?’ Whilst current practice is to treat pre‐operative bacteriuria in patients managed in urology departments, Herr [3] has shown it is reasonable not to give prophylactic antibiotics to asymptomatic patients undergoing flexible cystoscopy, even if there is bacteriuria on pre‐procedure urine analysis. Herr evaluated >3000 outpatients undergoing flexible cystoscopies (of whom 78% had sterile urine and 22% had asymptomatic bacteriuria). The cystoscopies were performed without any antibiotic prophylaxis at all. Overall, 1.9% of patients experienced febrile UTIs, all of which resolved rapidly with oral antibiotics and without any complications (no sepsis or hospital admission). Although the rate was higher in patients with prior infected urine (UTI rate 3.7% compared with 1.4% in patients with sterile urine), Herr concluded that prophylactic antibiotics are not necessary in asymptomatic patients regardless of the presence of bacteriuria, and therefore advised that pre‐procedure urine analysis itself is not required [3].

These findings challenge the belief that pre‐operative urine analysis is essential in asymptomatic patients. Kavoussi et al. [4] studied this issue in patients undergoing insertion of an artificial urinary sphincter or inflatable penile prosthesis, of whom 41% had no pre‐operative urine culture; the authors demonstrated a low risk of 1.5% of prosthesis infection in patients receiving standard peri‐operative antibiotics. This suggests that, even in ‘high stakes’ prosthetic implantation (where the consequences of infection are considerable, requiring explanation and later re‐insertion of a new device), surgery can be performed without pre‐operative urine cultures [4].

Perhaps even more contentiously, Cai et al. [5] have questioned the need for treatment of asymptomatic bacteriuria before urological procedures when ‘standard antibiotic prophylaxis’ is given pre‐operatively. They analysed 2201 patients treated in accordance with European Association of Urology guidelines for antibiotic prophylaxis, of whom 70.1% had sterile urine and 30.4% had asymptomatic bacteriuria pre‐operatively. They reported no increased risk in patients with pre‐operative asymptomatic bacteriuria, with 10.4% of affected patients having a symptomatic post‐operative UTI and a 0.3% risk of sepsis, compared with a 8.3% UTI rate and 0.26% chance of sepsis in patients with pre‐operatively sterile urine [5].

In their article, Deng et al. [2] have shown that patients with sterile urine undergoing ureteroscopy had a similar risk of a post‐operative febrile UTI whether or not pre‐ and post‐operative antibiotics were given. This implies the need for specific high‐risk groups to be targeted for antibiotic prophylaxis, and, extending the arguments above, suggests that a more selective approach is needed for pre‐operative urine analysis in low‐risk patients.

In this regard, Grabe and Wullt [6] have commented that ‘undetected pre‐operative bacteriuria is like walking straight into a minefield’. Whilst the knowledge that one is walking into a minefield has the advantage of leading one to take a cautious approach (i.e. treating asymptomatic bacteriuria pre‐operatively), it is possible that not all of the mines in the minefield are live (i.e. certain patients with asymptomatic bacteriuria may be at lower risk of post‐operative problems than others). The real challenge is to determine which patients with asymptomatic bacteriuria need antibiotic treatment and for how long, and therefore which patients need urine analysis before which procedures in the first place. This approach, if shown to be safe, would not only reduce the cost of urine cultures and pre‐surgical eradication of asymptomatic bacteriuria, but also the wider global cost of antibiotic overuse and bacterial resistance.

Daron Smithand Bruce Macrae
*EndoLuminal EndoUrologist, Department of Urology, Westmoreland Street Hospital, and Clinical Microbiology, UCLH NHS Foundation Trust, London, UK
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  1. WHO. Global action plan on antimicrobial resistance. 2015 (accessed March 23, 2018)https://apps.who.int/iris/bitstream/handle/10665/193736/9789241509763_eng.pdf?sequence=1
  2. Deng T, Liu B, Duan X et al. Antibiotic prophylaxis in ureteroscopic lithotripsy: a systematic review and meta‐analysis of comparative studies. BJU Int 2018122: 29–39
  3. Herr HW. The risk of urinary tract infection after flexible cystoscopy in patients with bladder tumor who did not receive prophylactic antibiotics. J Urol 2015193: 548–51
  4. Kavoussi NL, Viers BR, Pagilara TJ et al. Are urine cultures necessary prior to urologic prosthetic surgery? Sex Med Rev 20186: 157–61
  5. Cai T, Verze P, Palmieri A et al. Is preoperative assessment and treatment of asymptomatic bacteriuria necessary for reducing the risk of postoperative symptomatic urinary tract infections after urologic surgical procedures? Urology 201799: 100–5
  6. Grabe M, Wullt B. Re: Is preoperative assessment and treatment of asymptomatic bacteriuria necessary for reducing the risk of postoperative symptomatic urinary tract infection after urologic surgical procedures? Eur Urol 2017; 73: 476-477

Guideline of guidelines: kidney stones



Several professional organizations have developed evidence-based guidelines for the initial evaluation, diagnostic imaging selection, symptomatic management, surgical treatment, medical therapy, and prevention of recurrence for both ureteric and renal stones. The purpose of this article is to summarize these guidelines with reference to the strength of evidence. All guidelines endorse an initial evaluation to exclude concomitant infection, imaging with a non-contrast computed tomography scan, and consideration of medical expulsive therapy or surgical intervention depending on stone size and location. Recommends for metabolic evaluation vary by guideline, but all endorse increasing fluid intake to reduce the risk of recurrence.
GOG-KS key points
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