International Alliance of Urolithiasis (IAU) guideline on staghorn calculi management

BACKGROUND

The stone burden based management strategy reported in the guidelines published by different associations is well known for a long time. Staghorn calculi, representing the largest burden and most complex stones, is one of the most challenging cases to practicing urologists in clinical practice. The International Alliance of Urolithiasis (IAU) has released a series of guidelines on the management of urolithiasis.

PURPOSE

To develop a series of recommendations for the contemporary management management of staghorn calculi and to provide a clinical framework for urologists treating patients with these complex stones.

METHODS

A comprehensive literature search for articles published in English between 01/01/1976 and 31/12/2022 in the PubMed, OVID, Embase and Medline database is performed. A series of recommendations are developed and individually graded following the review of literature and panel discussion.

RESULTS

The definition, pathogenesis, pathophysiology, preoperative evaluation, intraoperative treatment strategies and procedural advice, early postoperative management, follow up and prevention of stone recurrence are summarized in the present document.

CONCLUSION

A series of recommendations regarding the management of staghorn calculi, along with related commentary and supporting documentation offered in the present guideline is intended to provide a clinical framework for the practicing urologists in the management of staghorn calculi.

Design and internal validation of S.I.C.K.: a novel nomogram predicting infectious and hemorrhagic events after percutaneous nephrolithotomy

BACKGROUND

Hemorrhagic and infectious events represent severe complications after percutaneous nephrolithotomy (PCNLs). Existing nephrolithometric nomograms have been introduced but their reliability in predicting complications is debated. We present a newly designed nomogram with intention to predict hemorrhagic/infectious events after PCNLs.

METHODS

We conducted a multicentric prospective study on adult patients undergoing standard (24 Fr) or mini (18 Fr) PCNL. Dataset was derived from previous RCT, where patients have been assigned to mini-PCNL or standard-PCNL to treat renal stones up to 40 mm. Aim of the study was to identify preoperative risk factors for early postoperative infectious/hemorrhagic complications including fever, septic shock, transfusion or angioembolization.

RESULTS

A total of 1980 patients were finally included. 992 patients (50.1%) received mini-PCNL and 848 standard PCNL (49.9%). The overall SFR was 86.1% with a mean maximum stone diameter of 29 mm (SD 25.0-35.0). 178 patients (8.9%) had fever,14 (0.7%) urosepsis, 24 patients (1.2%) required transfusion and 18 (0.9%) angioembolization. The overall complication was (11.7%). After multivariable analysis, the included elements in the nomogram were age (P=0.041), BMI (P=0.018), maximum stone diameter (P<0.001), preoperative hemoglobin (P=0.005), type 1/2 diabetes (P=0.05), eGFR<30 (P=0.0032), hypertension (>135/85 mmHg, P=0.001), previous PCNL or pyelo/nephrolithotomy (P=0.0018), severe hydronephrosis (P=0.002). After internal validation, the AUC of the model was 0.73.

CONCLUSIONS

This is the first nomogram predicting infections and bleedings after PCNLs, it shows a good accuracy and can support clinicians in their patients' peri-operative workout and management.

Long-term Outcomes of Minimally Invasive Rendezvous Procedures to Treat Complex Ureteric Strictures and Injuries

Background

Complex ureteric strictures and injuries occurring during major abdominal and pelvic operations may cause significant morbidity and distress to patients. A rendezvous procedure is an endoscopic technique used in case of such injuries.

Objective

To evaluate perioperative and long-term outcomes of rendezvous procedures to treat complex ureteric strictures and injuries.

Design setting and participants

We retrospectively reviewed patients undergoing a rendezvous procedure for ureteric discontinuity including strictures and injuries, treated between 2003 and 2017 at our Institution and completing at least 12 mo of follow-up. We divided patients into two groups: early postsurgical obstruction, leakage, or detachment (group A) and late strictures (oncological/postsurgical; group B).

Outcome measurements and statistical analysis

If appropriate, we performed a retrograde study ± rigid ureteroscopy to assess the stricture 3 mo after the rendezvous procedure, followed by a MAG3 renogram at 6 wk, 6 mo, and 12 mo, and annually thereafter for 5 yr.

Results and limitations

Forty-three patients underwent a rendezvous procedure, 17 in group A (median age 50 yr, range 30-78) and 26 in group B (median age 60 yr, range: 28-83). Ureteric strictures and ureteric discontinuities were stented successfully in 15 out of 17 patients in group A (88.2%) and 22 out of 26 patients (84.6%) in group B. For both groups, the median follow-up was 6 yr. In group A, of 17 patients, 11 (64.7%) were stent free with no further interventions, two (11.7%) had a subsequent Memokath stent insertion (38%), and two (11.7%) required reconstruction. Of 26 patients in group B, eight (30.7%) required no further interventions and were stent free, ten (38.4%) were maintained with long-term stenting, and one was managed with a Memokath stent (3.8%). Of the 26 patients, only three (11.5%) required major reconstruction, while four patients with malignancy (15%) died during follow-up.

Conclusions

With a combined antegrade and retrograde approach, the majority of complex ureteric strictures/injuries can be bridged and stented with an overall immediate technical success rate of above 80%, avoiding major surgery in unfavourable circumstances and allowing time for stabilisation and recovery of the patient. Additionally, in case of technical success, further interventions may be unnecessary in up to 64% of patients with acute injury and about 31% of patients with late stricture.

Patient summary

The majority of complex ureteric strictures and injuries can be resolved using a rendezvous approach, avoiding major surgery in unfavourable circumstances. Moreover, this approach can help avoid further interventions in 64% of such patients.

Learning Curve for Endoscopic Combined Intra-Renal Surgery Using Vacuum-Assisted Device

INTRODUCTION

The aim of the study was to provide data related to endoscopic combined intra-renal surgery learning curve using minimally invasive techniques with vacuum-assisted devices. Minimal data exist on the learning curve for these techniques.

METHODS

We conducted a prospective study monitoring the training of a mentored surgeon learning ECIRS with vacuum assistance. We use varied parameters for improvements. After collection of peri-operative data, tendency lines and CUSUM analysis were used to investigate the learning curves.

RESULTS

111 patients have been included. Guy's Stone Score 3 and 4 stones 51.3% of all cases. The mostly used percutaneous sheath was 16 Fr (87.3%). SFR was 78.4%. 52.3% patients were tubeless, and 38.7% achieved trifecta. High-degree complication rate was 3.6%. Operative time improved after 72 cases. We observed a decrease of complications throughout the case series, with improvement after 17 cases. In terms of trifecta, proficiency was reached after 53 cases. Proficiency seems achievable in a limited number of procedures, but results did not plateau. Higher number of cases might be necessary for excellence.

DISCUSSION

A surgeon learning ECIRS with vacuum assistance can obtain proficiency in 17-50 cases. The number of procedures required for excellence remains unclear. Exclusion of more complex cases might positively affect the training, reducing unnecessary complications.

14F Super-Mini Percutaneous Cystolitholapaxy: A Novel Technique in the Treatment of Bladder Stones

Introduction: This single-center experience describes the indications, novel technique, and outcomes of performing 14F super-mini percutaneous cystolitholapaxy (14F-SMPCCL). Materials and Methods: Cases between 2019 and 2022 were retrospectively identified with surgical outcomes recorded. Using percutaneous access to the bladder, an endoscope was inserted through the ClearPetra 14F super-mini sheath and laser lithotripsy completed with stone fragments suctioned out. Results: Sixteen cases were included in the study and all patients were adults. Average conglomerate stone size was 28.1 mm (range = 10-50 mm). Average operative time was 60.0 minutes (range = 23-110 minutes). Visual stone-free rate was 91.7%, radiologic stone-free rate was 81.3%, and average postoperative length of stay was 1 day. One patient developed urosepsis postoperatively and there were no other complications. Conclusion: The novel technique of 14F-SMPCCL is safe and feasible for treating large burdens of bladder stones with a conglomerate size of ∼2.5 to 5 cm. Active suction allows for efficient removal of stone fragments.

Stone-scoring systems for predicting complications in percutaneous nephrolithotomy: A systematic review of the literature

Objective

Percutaneous nephrolithotomy is a treatment of choice for larger stones of the upper urinary tract. Currently, several nephrolithometric nomograms for prediction of post-operative surgical outcomes have been proposed, although uncertainties still exist regarding their roles in the estimation of complications.

Methods

We conducted a systematic review on PubMed and Web of Sciences databases including English studies with at least 100 cases and published between January 2010 and December 2021. We identified original articles evaluating correlations between the Guy's stone score, the stone size (S), tract length (T), obstruction (O), number of involved calices (N), and essence or stone density (E) (S.T.O.N.E.), Clinical Research Office of the Endourological Society (CROES), and Seoul National University Renal Stone Complexity (S-ReSC) scores and post-operative complications in adult patients. We also included newly designed nomograms for prediction of specific complications.

Results

After an initial search of 549 abstracts, we finally included a total of 18 papers. Of them, 11 investigated traditional nephrolithometric nomograms, while seven newly designed nomograms were used to predict specific complications. Overall, 7316 patients have been involved. In total, 14 out of 18 papers are derived from retrospective single-center studies. Guy's stone score obtained correlation with complications in five, S.T.O.N.E. nephrolithometry score in four, while CROES score and S-ReSC score in three and two, respectively. None of the studies investigated minimally invasive percutaneous nephrolithotomy (PCNL) and all cases have been conducted in prone position. Considering newly designed nomograms, none of them is currently externally validated; five of them predict post-operative infections; the remaining two have been designed for thromboembolic events and urinary leakage.

Conclusion

This review presents all nomograms currently available in the PCNL field and highlights a certain number of concerns. Published data have appeared contradictory; more recent tools for prediction of post-operative complications are frequently based on small retrospective cohorts and lack external validations. Heterogeneity among studies has also been noticed. More rigorous validations are advisable in the future, involving larger prospective patients' series and with the comparison of different tools.

Reliability of nephrolithometric nomograms in patients treated with minimally invasive percutaneous nephrolithotomy: A precision study

Objectives

The study aimed to evaluate quality of nephrolithometric nomograms to predict stone-free rates (SFRs) and complication rates (CRs) in case of minimally invasive percutaneous nephrolithotomy (PNL). In the last decade, nomograms have been introduced to estimate the SFRs and CRs of PNL. However, no data are available regarding their reliability in case of utilization of miniaturized devices. Herein we present a prospective multicentric study to evaluate reliability of Guy's stone score (GSS), the stone size, tract length, obstruction, number of involved calyces, and essence of stone (S.T.O.N.E.) nephrolithometry score and Clinical Research Office of the Endourological Society (CROES) score in patients treated with minimally invasive PNL.

Methods

We evaluated SFRs and CRs of 222 adult patients treated with miniaturized PNL. Patients were considered stone-free if no residual fragments of any size at post-operative unenhanced computed tomography scan. Patients demographics, SFRs, and CRs were reported and analyzed. Performances of nomograms were evaluated with the area under the curve (AUC).

Results

We included 222 patients, the AUCs of GSS, CROES score, and S.T.O.N.E. nephrolithometry score were 0.69 (95% confidence interval [CI] 0.61-0.78), 0.64 (95% CI 0.56-0.73), and 0.62 (95% CI 0.52-0.71), respectively. Regarding SFRs, at multivariate binomial logistic regression, only the GSS had significance with an odds ratio of 0.53 (95% CI 0.31-0.95, p=0.04). We did not find significant correlation with complications, with only a trend for GSS.

Conclusion

This is the first study evaluating nomograms in miniaturized PNL. They still show good reliability; however, our data showed lower performances compared to standard PNL. We emphasize the need of further studies to confirm this trend. A dedicated nomogram for minimally invasive PNL may be necessary.

International Alliance of Urolithiasis (IAU) Guideline on percutaneous nephrolithotomy

The International Alliance of Urolithiasis (IAU) would like to release the latest guideline on percutaneous nephrolithotomy (PCNL) and to provide a clinical framework for surgeons performing PCNLs. These recommendations were collected and appraised from a systematic review and assessment of the literature covering all aspects of PCNLs from the PubMed database between January 1, 1976, and July 31, 2021. Each generated recommendation was graded using a modified GRADE methodology. The quality of the evidence was graded using a classification system modified from the Oxford Center for Evidence-Based Medicine Levels of Evidence. Forty-seven recommendations were summarized and graded, which covered the following issues, indications and contraindications, stone complexity evaluation, preoperative imaging, antibiotic strategy, management of antithrombotic therapy, anesthesia, position, puncture, tracts, dilation, lithotripsy, intraoperative evaluation of residual stones, exit strategy, postoperative imaging and stone-free status evaluation, complications. The present guideline on PCNL was the first in the IAU series of urolithiasis management guidelines. The recommendations, tips and tricks across the PCNL procedures would provide adequate guidance for urologists performing PCNLs to ensure safety and efficiency in PCNLs.

European Association of Urology Section of Urolithiasis and International Alliance of Urolithiasis Joint Consensus on Retrograde Intrarenal Surgery for the Management of Renal Stones

BACKGROUND

Retrograde intrarenal surgery (RIRS) has become the preferred treatment modality for nephrolithiasis. However, because of ongoing uncertainties regarding the optimal perioperative management, operative technique, and postoperative follow-up, as well as a lack of standardization for outcome reporting, consensus is needed to achieve more uniform clinical practice worldwide.

OBJECTIVE

To develop recommendations for RIRS on the basis of existing data and expert consensus.

DESIGN, SETTING, AND PARTICIPANTS

A protocol-driven, three-phase study was conducted by the European Association of Urology Section of Urolithiasis (EULIS) and the International Alliance of Urolithiasis (IAU). The process included: (1) a nonsystematic review of the literature to define domains for discussion; (2) a two-round modified Delphi survey involving experts in this field; and (3) an additional group meeting and third-round survey involving 64 senior representative members to formulate the final conclusions.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The results from each previous round were returned to the participants for re-evaluation of their decisions during the next round. The agreement threshold was set at 70%.

RESULTS AND LIMITATIONS

The panel included 209 participants who developed 29 consensus statements on the following topics of interest: (1) perioperative infection management; (2) perioperative antithrombotic therapy; (3) fundamentals of the operative technique; and (4) standardized outcome reporting. Although this consensus can be considered as a useful reference for more clinically oriented daily practice, we also acknowledge that a higher level of evidence from further clinical trials is needed.

CONCLUSIONS

The consensus statements aim to guide and standardize clinical practice and research on RIRS and to recommend standardized outcome reporting.

PATIENT SUMMARY

An international consensus on the best practice for minimally invasive surgery for kidney stones was organized and developed by two international societies. It is anticipated that this consensus will provide further guidance to urologists and may help to improve clinical outcomes for patients.

Introducing Trifecta for percutaneous nephrolithotomies: a proposal for standard reporting outcomes after treatment for renal stones

BACKGROUND

In literature, the reports of outcomes after percutaneous nephrolithotomies are rather heterogeneous. This may influence studies comparison, it may also render difficult to evaluate surgical adequacy, peri-operative morbidity and patient's quality of life between studies. For this reason, we propose to introduce PNL-Trifecta as composite measure to standardize data reporting outcomes after percutaneous nephrolithotomies.

METHODS

We performed a prospective multicentric study on consecutive patients undergone PNL to treat renal stones between 2018 and 2020. Successful PNL-trifecta was considered achieved when procedures obtained the three following results: no residual fragments > 2mm at unenhanced CT scan at 3 months post-op, no complications (defined as Clavien-Dindo Score 0) and operation carried out without placing a nephrostomy tube (tubeless or totally tubeless). We compared results of standard versus mini-PNL and between stones of different complexity (evaluated with Guy's Stone Score and S.T.O.N.E. nephrolithometry Score). Univariate analysis was utilized to identify other factors influencing achievement of PNL-Trifecta.

RESULTS

245 patients fulfilled inclusion/exclusion criteria and have been enrolled in the study (median age: 56, IQR 48-57). The overall PNL-Trifecta achievement rate was 22.85% (28.66% in the mini-PNL group and 13.68% in the standard-PNL group, p=0.010). The stone free rate, CD 0 rate and tubeless/totally tubeless rate in the mini-PNL group were 60.66%, 89.33% and 51.33% respectively. In the standard-PNL group they were 44.21%, 40.00% and 15.78% respectively. At the univariate analysis, differences between Guy's Stone Score groups in achieving PNL-Trifecta were significant (p=0.001). Also, the level of upper puncture (p=0.010) and utilization of device with active suction (p=0.002) showed statistically significant differences. Furthermore, the length of stay in the patient's group achieving Trifecta was 2.28 versus a mean length of stay of 4.64 days in the group of patients not achieving Trifecta (p=0.046).

CONCLUSIONS

We present Trifecta for PNLs as a potential tool to evaluate quality of percutaneous nephrolithotomies and to provide an instrument for an adequate standard data reporting. It can represent a valid way to assess and monitor surgeon's learning curves. It will require further external validation and studies to evaluate its correlation with mid- and long-term results and patient's health related quality of life outcomes.

European Association of Urology Section of Urolithiasis and International Alliance of Urolithiasis Joint Consensus on Percutaneous Nephrolithotomy

CONTEXT

Although percutaneous nephrolithotomy (PCNL) has been performed for decades and has gone through many refinements, there are still concerns regarding its more widespread utilization because of the long learning curve and the potential risk of severe complications. Many technical details are not included in the guidelines because of their nature and research protocol.

OBJECTIVE

To achieve an expert consensus viewpoint on PCNL indications, preoperative patient preparation, surgical strategy, management and prevention of severe complications, postoperative management, and follow-up.

EVIDENCE ACQUISITION

An international panel of experts from the Urolithiasis Section of the European Association of Urology, International Alliance of Urolithiasis, and other urology associations was enrolled, and a prospectively conducted study, incorporating literature review, discussion on research gaps (RGs), and questionnaires and following data analysis, was performed to reach a consensus on PCNL.

EVIDENCE SYNTHESIS

The expert panel consisted of 36 specialists in PCNL from 20 countries all around the world. A consensus on PCNL was developed. The expert panel was not as large as expected, and the discussion on RGs did not bring in more supportive evidence in the present consensus.

CONCLUSIONS

Adequate preoperative preparation, especially elimination of urinary tract infection prior to PCNL, accurate puncture with guidance of fluoroscopy and/or ultrasonography or a combination, keeping a low intrarenal pressure, and shortening of operation time during PCNL are important technical requirements to ensure safety and efficiency in PCNL.

PATIENT SUMMARY

Percutaneous nephrolithotomy (PCNL) has been a well-established procedure for the management of upper urinary tract stones. However, according to an expert panel consensus, core technical aspects, as well as the urologist's experience, are critical to the safety and effectiveness of PCNL.

The characteristic and relationship of Escherichia coli isolated from urine and stones in patients with calcium oxalate stones

Previous clinical studies have shown that Escherichia coli (E. coli) predominated in urine and stone culture from calcium oxalate (CaOx) stone disease. The characteristic and relationship between E. coli isolated from urine cultures (EUC) and stone cultures (ESC) are compared. 83 E. coli (33 EUC and 50 ESC, respectively) from 66 CaOx stone patients were recruited in the study. E. coli in urine and stones from those patients were assessed by antimicrobial susceptibility test, genotyping and phylogenetic grouping. Furthermore, whole genome sequencing and comparative genomic analysis in paired ESC and EUC isolated strains from eight patients were carried out. The E. coli strains from ESC and EUC were not only multidrug resistant (MDR), but also had the similar pattern of resistant genes. The dominant phylogenetic group was B2, which was found in 54.0% of the ESC samples and 69.7% of the EUC samples, respectively. The virulence genes of E. coli, which isolated from stones and urine in the same patients, were highly homologous and largely consistent. Meanwhile, these E. coli strains were located in the same clade originated from a common ancestor. ESC and EUC isolated from patients with CaOx stones had a high prevalence of phylogenetic groups B2. Bacterial strains isolated from urine and stones in the same patient had consistent antimicrobial susceptibility profiles, genotyping, phylogenetic groups, virulence and resistance genes, also with high sequence co-linearity and close relationships.

Classification and standardized reporting of percutaneous nephrolithotomy (PCNL): International Alliance of Urolithiasis (IAU) Consensus Statements

BACKGROUND

The aim of this study was to reach a consensus in the classification and standardized reporting for the different types of PCNLs.

METHODS

The RAND/UCLA appropriateness methodology was used to reach a consensus. Thirty-two statements were formulated reviewing the literature on guidelines and consensus on PCNLs, and included procedure specific details, outcome measurements and a classification for PCNLs. Experts were invited to two rounds of input, the first enabled independent modifications of the proposed statements and provided the option to add statements. The second round facilitated scoring of all statements. Each statement was discussed in the third round to decide which statements to include. Any suggestion or disagreement was debated and discussed to reach a consensual agreement.

RESULTS

Twenty-five recommendations were identified to provide standardized reporting of procedure and outcomes. Consensual scoring above 80% were strongly agreed upon by the panel. The top treatment related outcomes were size of sheath used (99.1%) and position for PCNL (93.5%). The highest ranked Outcome Measures included definition of postoperative hospital length of stay (94.4%) and estimated blood loss (93.5%).

CONCLUSIONS

The consensus statements will be useful to clarify operative technique, in the design of clinical trials and standardized reporting, and presentation of results to compare outcomes of different types of PCNLs.

Classification and Standardized Reporting of Percutaneous Nephrolithotomy (PCNL): International Alliance of Urolithiasis (IAU) consensus statements

BACKGROUND

To reach a consensus in the classification and standardized reporting for the different types of PCNLs.

METHODS

The RAND/UCLA appropriateness methodology was used to reach a consensus. Thirty-two statements were formulated reviewing the literature on guidelines and consensus on PCNLs, and included procedure specific details, outcome measurements and a classification for PCNLs. Experts were invited to two rounds of input, the first enabled independent modifications of the proposed statements and provided the option to add statements. The second round facilitated scoring of all statements. Each statement was discussed in the third round to decide which statements to include. Any suggestion or disagreement was debated and discussed to reach a consensual agreement.

RESULTS

Twenty-five recommendations were identified to provide standardised reporting of procedure and outcomes. Consensual scoring above 80% were strongly agreed upon by the panel. The top treatment related outcomes were size of sheath used (99.1%) and position for PCNL (93.5%). The highest ranked Outcome Measures included definition of post-operative hospital length of stay (94.4%) and estimated blood loss (93.5%).

CONCLUSIONS

The consensus statements will be useful to clarify operative technique, in the design of clinical trials and standardized reporting, and presentation of results to compare outcomes of different types of PCNLs.

Retained Urethral Catheter in the Ureter Following Misplaced Insertion in a Postpartum Female

Background: Urethral catheterization is a common procedure, with a low complication rate. Aberrant catheterization into a ureter is a rare complication. We present a case of an aberrant urethral catheterization into the right ureter in a postpartum female. Case Presentation: An 18-year-old primigravida female presented with loin pain and catheter bypassing after a postpartum urethral catheterization. Examination under anesthesia and cystoscopy revealed the catheter leading into the right ureter, which was confirmed by subsequent CT urogram. Multiple attempts to remove the catheter failed. A rigid ureteroscopy was performed, revealing "kinking" of the catheter just distal to the balloon, as a result of an asymmetrical inflated balloon. A laser fiber inserted through the ureteroscope punctured the balloon, allowing balloon deflation and catheter removal under screening. A relook ureteroscopy 8 weeks later confirmed a healed ureter. Conclusion: Asymmetric catheter balloon inflation causes kinking of a catheter and occlusion of the balloon port that will prohibit balloon deflation. During rigid ureteroscopy, a laser fiber can be used to puncture the catheter balloon, allowing balloon deflation and catheter removal.

[Evolution and miniaturization of percutaneous nephrolithotomy]

Percutaneous nephrolithotomy (PCNL) was at first indicated for larger renal stones. Technological progress allowed a significant improvement of the available equipment, mostly to miniaturize the devices. However, this should not affect the stone clearance. Many different techniques arised aiming to reduce the complications of PCNL, in particular the risk of haemorrhage. As it becomes less invasive, the indications are greatly expanded, and a growing number of patients will benefit from it in the future. This explains the significance of knowing this procedure in continual development in greater detail.

Percutaneous Nephrolithotomy and Spina Bifida: Complex Major Stone Surgery?

BACKGROUND

The incidence of spina bifida (SB) is ∼1:1000, and risk of stone disease is substantially raised in SB. This is the unique published study of the outcome of patients with SB undergoing percutaneous nephrolithotomy (PCNL) compared to a neurologically intact historically matched control group at the same institution.

PATIENTS AND METHOD

A series of 96 PCNLs in 13 SB and 50 non-SB patients was analyzed. The following measurements were recorded: (1) Comorbidities; (2) Preoperative: (renal function, American Society of Anesthesiologists [ASA] score); (3) Intraoperative: (anesthesia time, number of tracks, stone-free rate); and (4) Postoperative: (sepsis, intensive therapy unit and total length of stay, transfusion rate, stone composition, rate of stone disease-related nephrectomy).

RESULTS

Retrograde access to the ureter was impossible in all cases of SB. The median ASA grade (OR 10.5, 95% confidence interval [CI] 2.6-42.7) and operative time (median difference 30 minutes, 95% CI 20-40) were both higher in the SB cohort. Surgeon's estimate of stone-free rate was significantly lower in the SB cohort (46% vs 82%). Intensive care requirement (0.29 days/PCNL vs 0.1 days/PCNL); total hospital stay (7 days vs 4 days); postoperative transfusion rate (11.8% vs 1.6%); and sepsis rate (38% vs 1.6%) were all significantly higher in the SB group. Repeat PCNL and nephrectomy for recurrent stone disease were both significantly increased in SB cohort compared to control group.

CONCLUSIONS

PCNL in patients with SB is associated with multiple parameters of poor outcome. Patients with SB should be counseled about increased peri-operative risk and likelihood of stone recurrence. In an era where hospitals are judged according to comparative outcomes, a case may be made for comparing PCNL in this cohort of patients separately because of the significantly increased peri- and postoperative morbidity.

An update and practical guide to renal stone management

Renal stone disease covers kidney and lower urinary tract stones caused by a variety of conditions, including metabolic and inherited disorders, and anatomical defects with or without chronic urinary infection. Most cases are idiopathic, in which there is undoubtedly a genetic predisposition, but where environmental and lifestyle factors play an important role. Indeed, it is becoming apparent that renal stone disease is often part of a larger 'metabolic picture' commonly associated with type 2 diabetes, obesity, dyslipidaemia, and hypertension. Renal stone disease is a growing problem in the UK (and other developed and developing populations) with a cross-sectional prevalence of ∼1.2%. This means that there are currently ∼720,000 individuals with a history of kidney stones in the UK. Almost 40% of first-time stone formers will form a second stone within 3 years of the first episode if no prophylactic measures are instituted to prevent stone recurrence, since removal or disintegration of the first stone does not treat the underlying cause of stones in the majority of patients. The age of onset is getting younger and the sex ratio (until recently more men than women) is becoming almost even. Metabolic screening remains an important part of investigating renal stone disease, but to the disappointment and frustration of many doctors, medical treatment is still essentially pragmatic, except perhaps in cystinuria, and to a limited extent in primary hyperoxaluria (if pyridoxine-sensitive); although newer treatments may be emerging. This review summarizes current thinking and provides a practical basis for the management of renal stone disease.

Heat-shock protein 25 ameliorates calcium oxalate crystal-mediated oxidative stress in renal epithelial cells

OBJECTIVE

To investigate whether the antioxidant protection attributed to small heat-shock proteins (sHSPs) affects calcium oxalate stone formation, a pro-oxidant disease.

MATERIALS AND METHODS

Canine distal tubular epithelial cells (Madin-Darby canine kidney, MDCK cells) were grown as confluent monolayers. Treatment regimens included control and HS-treated cells (37 degrees C and 42 degrees C for 1 h) with or without calcium oxalate monohydrate (COM) or free oxalate treatment (28 microg/cm2) 16 h later. In digitonin-permeabilized cells, O2- was measured by lucigenin-enhanced chemiluminescence over a 5-min period, to measure mitochondrial O2- production. Protein expression was assessed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis Western blot analysis using specific antibodies.

RESULTS

COM significantly increased O2- production in MDCK cells. HS treatment, which up-regulated HSP25 expression, significantly decreased this O2- production (P < 0.05) but had no effect in control cells. In COM-treated cells (20 h) there was a marked and significant down-regulation of both HSP 25, HSP 70 and heme oxygenase-1 expression compared to cells treated with HS alone (P < 0.05). Free oxalate had no effect on HSP 25 expression.

CONCLUSIONS

The results suggest that the COM-induced increase in mitochondrial O2- production in MDCK cells is ameliorated by HSP 25 up-regulation via HS. Specific COM inhibition of HSP 25, HSP 70 and heme oxygenase-1 up-regulation suggests that COM-induced reactive oxygen species damage is unable to benefit from HSP-associated physiological resistance.

The effect of image size on screen-positive rates for nuchal translucency screening

It has been shown previously that the absolute measurement of nuchal translucency (NT) thickness, one of the most effective screening tests for fetal Down syndrome, significantly decreases with increasing image size. We undertook a prospective study to assess whether this effect materially alters the NT-derived risk estimation for fetal Down syndrome. In 350 women, NT was measured at both 100 and 200% image sizes. The median NT measurement at 200% was 8% smaller than at 100%. The screen-positive rates at 100 and 200% image sizes were 5.1% (18/350) and 2.3% (8/350), respectively (P= 0.048). Altering the image magnification settings is likely to decrease the sensitivity of NT-derived Down syndrome risk estimation. Further study is required to test the effect of our finding on the sensitivity of NT screening and to assess whether adjustments in gain settings mitigate the effect.

Dystrophic ureteral calcification associated with Churg-Strauss vasculitis

Churg-Strauss syndrome is an uncommon systemic vasculitis affecting small blood vessels. Renal involvement is typical; however, calcinosis of the urinary tract has not previously been described. Dystrophic calcification in the urinary tract is rare, although it is occasionally associated with schistosomiasis, tuberculosis, and polyarteritis nodosa. We report the case of a 19-year-old man with newly diagnosed Churg-Strauss syndrome who presented to us with dystrophic calcification in both ureters causing bilateral obstruction.

Pelvi-calyceal height, a predictor of success when treating lower pole stones with extracorporeal shockwave lithotripsy

Extra corporeal shockwave lithotripsy (ESWL) is the treatment of choice for the majority of renal stones, however, it has the lowest success rate in complete clearance of stones located in the lower pole. We assess whether pelvi-calyceal height is a useful measurement in predicting successful stone clearance from the lower pole. A total of 105 patients with a solitary lower pole calculus of less than 20 mm treated with ESWL were reviewed. Stone size, location and pelvi-calyceal height were measured by intravenous urogram. Success was defined as complete stone clearance. Fifty-four patients (51.4%) had successful treatments, with the remaining 51 (48.6%) having incomplete stone clearance (including two patients in whom treatment had no effect). There was a statistically significant difference (P<0.0001) in pelvi-calyceal height between the two groups. Mean pelvi-calyceal height in patients with complete stone clearance was 15.1 mm (SD=3.9) compared with 22.9 mm (SD=5.2) for those with incomplete clearance. Pelvi-calyceal height is a useful predictor of success when treating lower pole renal stones with ESWL.

Renal Stone Disease: The Urological Perspective

Percutaneous nephrolithotomy, extracorporeal lithotripsy and ureteroscopy have changed the face of urolithiasis. Open surgery is becoming extremely rare today. Nevertheless, the cooperation between nephrologist and urologist remains essential and is the only way to prevent recurrence.

Rupture and perforation of urinary reservoirs made from bowel

A review of the literature involving the rupture or perforation of urinary reservoirs made from the bowel indicates that this complication is perhaps not as rare as commonly perceived. It is a severe complication for which a high index of suspicion needs to be maintained. Physicians attending to patients with such urinary reconstructions should be aware that the diagnosis is often difficult to confirm without resorting to exploratory laparotomy and in particular that a negative cystogram can be misleading. A practical suggestion to help alert these physicians to the possibility of a ruptured urinary reconstruction is that such patients should carry a medical card stating the type of reservoir they have along with their special circumstances. From the reported experiences, it is, however, clear that in carefully selected cases and with vigilant monitoring, some patients may be managed non-operatively.

Ultrasound prediction of risk of spontaneous miscarriage in live embryos from assisted conceptions

OBJECTIVE

An accurate method to predict subsequent miscarriage in live embryos has not yet been established. This pilot study aimed to determine the most discriminatory ultrasound-based model for predicting spontaneous miscarriage after embryonic life was first detected in assisted conceptions. A method for estimating individual risk of miscarriage was developed.

METHODS

This was a prospective cross-sectional survey of 322 live singleton embryos in women from an assisted reproductive technology program. Mean sac diameter (MSD), crown-rump length (CRL), embryonic heart rate (EHR), maternal age and gestational age at the first transvaginal scan detecting embryonic life (between 42 and 62 days) were observed. These variables were included in a multivariate model for predicting spontaneous miscarriage occurring prior to 20 weeks. MSD, CRL and MSD minus CRL were assessed in univariate logistic regression analyses. The global diagnostic accuracy of each model was compared directly using receiver-operating characteristics (ROC) curves.

RESULTS

The multivariate model demonstrated the best ROC curve for predicting miscarriage (ROC area 0.87; 95% CI, 0.80-0.95). The separate univariate analyses had less diagnostic accuracy. In particular, MSD - CRL had a significantly smaller ROC area (0.65) than did the multivariate model (P < 0.01).

CONCLUSIONS

The most discriminatory test for predicting spontaneous miscarriage in live embryos was a multivariate model, which allows estimation of individual risk levels.

Epidemiology of paediatric renal stone disease in the UK

BACKGROUND

The previous epidemiological study of paediatric nephrolithiasis in Britain was conducted more than 30 years ago.

AIMS

To examine the presenting features, predisposing factors, and treatment strategies used in paediatric stones presenting to a British centre over the past five years.

METHODS

A total of 121 children presented with a urinary tract renal stone, to one adult and one paediatric centre, over a five year period (1997-2001). All children were reviewed in a dedicated stone clinic and had a full infective and metabolic stone investigative work up. Treatment was assessed by retrospective hospital note review.

RESULTS

A metabolic abnormality was found in 44% of children, 30% were classified as infective, and 26% idiopathic. Bilateral stones on presentation occurred in 26% of the metabolic group compared to 12% in the infective/idiopathic group (odds ratio 2.7, 95% CI 1.03 to 7.02). Coexisting urinary tract infection was common (49%) in the metabolic group. Surgically, minimally invasive techniques (lithotripsy, percutaneous nephrolithotomy, and endoscopy) were used in 68% of patients.

CONCLUSIONS

There has been a shift in the epidemiology of paediatric renal stone disease in the UK over the past 30 years. Underlying metabolic causes are now the most common but can be masked by coexisting urinary tract infection. Treatment has progressed, especially surgically, with sophisticated minimally invasive techniques now employed. All children with renal stones should have a metabolic screen.

Mid-trimester fetal subdural hemorrhage: prenatal diagnosis

A routine antenatal ultrasound examination at 20 weeks' gestation revealed a space-occupying lesion in the fetal right cerebral hemisphere. The borders of the mass were indistinct and there was no midline shift. A small collection of echogenic bowel was identified at the right iliac fossa. In an attempt to explain both findings a provisional diagnosis of a fetal blood dyscrasia was made. Fetal cranial magnetic resonance imaging 24 h later confirmed the diagnosis of a subdural hemorrhage. Subsequent fetal blood sampling confirmed severe fetal thrombocytopenia. To our knowledge this is the first report of the antenatal diagnosis of spontaneous mid-trimester fetal subdural hemorrhage.

Catheter associated urinary tract infection and encrustation

This paper examines the relationship between urinary pH, infection and urinary catheter encrustation and discusses the current management and problems of catheter associated urinary infection and encrustation.

Couch or crouch? Examining the prostate: a randomized study comparing the knee-elbow and the left-lateral position

OBJECTIVE

To compare two methods of examining the prostate, the knee-elbow (KE) and left-lateral (LL) positions, to establish which allows a more complete examination, and to determine if there is any difference in patients' perception of pain or embarrassment for either method.

PATIENTS AND METHODS

All men attending two urology clinics who required a prostate examination were eligible for the study. Both the KE and LL methods were used for each participant, by the same clinician. The order in which the examinations were conducted was randomized using the last digit of the patient's hospital number.

RESULTS

Five clinicians examined 117 men; three patients refused to participate and the examination data were incomplete for two. Irrespective of the order in which the examinations were conducted (P = 0.6), the KE position permitted a greater proportion of the prostate to be palpated (Wilcoxon signed-ranks test, z = -4.7, P < 0.001) in 35% of patients, but there was no difference in 60%. Most patients found the examinations equally painful and embarrassing. However, for those who expressed a difference, the KE was 1.9 times more comfortable than the LL position and twice as embarrassing.

CONCLUSION

The two methods of prostate examination were equal for completeness of examination, pain and embarrassment in most patients. However, the KE offers an alternative to the LL position for those patients in whom the prostate is difficult to palpate or who find the examination painful.

The management of paediatric urolithiasis

OBJECTIVE

To evaluate the efficacy and safety of the management of paediatric urolithiasis by extracorporeal shock wave lithotripsy (ESWL), endoscopic ureterolithotomy, percutaneous nephrolithotomy (PCNL) and open nephrolithotomy.

PATIENTS AND METHODS

In a 3-year period (1997-1999), 59 children were treated for urolithiasis and underwent a total of 79 procedures. Thirty-two ESWL sessions were performed in 23 children (mean age 7.4 years, median 6.0). PCNL was undertaken in 30 renal units in 25 children (mean age 6.4 years, median 4.0). Eight patients (mean age 7.8 years, median 5) underwent 17 ureteroscopic procedures, six of which involved the use of a holmium laser. Three children with staghorn calculi underwent open nephrolithotomy under conditions of renal ischaemia and hypothermia.

RESULTS

Of the 23 children treated using ESWL, 21 (91%) became stone-free; 17 underwent one ESWL session (74%), three had two sessions and three (13%) had three sessions. All eight patients who underwent ureteroscopy became stone-free. Four patients in whom the stone could not be reached by ureteroscopy initially had a JJ stent inserted, and the stone and stent subsequently removed. Stones were cleared using PCNL in 27 of 30 renal units (90%); three patients who had residual stone fragments were rendered stone-free by ESWL. Two of three children undergoing open nephrolithotomy were stone-free after surgery and the remaining one rendered stone-free with ESWL. Metabolic evaluation showed that 25 of 45 children (55%) had a urinary infection, eight (18%) had hyperoxaluria, three (7%) had hypercalciuria, two (4%) had cystinuria, and no identifiable cause was found in seven (16%). Treatment by a single modality rendered 52 of the 59 children (88%) stone-free; when the different modalities were combined, 57 of 59 patients (97%) were cleared of their stones.

CONCLUSIONS

Technological advances in ESWL, ureteroscopy and PCNL have had a significant effect on the management of urolithiasis in children, allowing a safe and successful outcome. The comprehensive care of children with urolithiasis should include a full metabolic evaluation. Anatomical anomalies contribute to the complexity of many cases, necessitating a close liaison between adult and paediatric urologists, nephrologists and radiologists to optimize stone management in children.

Reperfusion injury pathophysiology in sickle transgenic mice

Reperfusion of tissues after interruption of their vascular supply causes free-radical generation that leads to tissue damage, a scenario referred to as "reperfusion injury." Because sickle disease involves repeated transient ischemic episodes, we sought evidence for excessive free-radical generation in sickle transgenic mice. Compared with normal mice, sickle mice at ambient air had a higher ethane excretion (marker of lipid peroxidation) and greater conversion of salicylic acid to 2,3-dihydroxybenzoic acid (marker of hydroxyl radical generation). During hypoxia (11% O(2)), only sickle mice converted tissue xanthine dehydrogenase to oxidase. Only the sickle mice exhibited a further increase in ethane excretion during restitution of normal oxygen tension after 2 hours of hypoxia. Only the sickle mice showed abnormal activation of nuclear factor-kappaB after exposure to hypoxia-reoxygenation. Allopurinol, a potential therapeutic agent, decreased ethane excretion in the sickle mice. Thus, sickle transgenic mice exhibit biochemical footprints consistent with excessive free-radical generation even at ambient air and following a transient induction of enhanced sickling. We suggest that reperfusion injury physiology may contribute to the evolution of the chronic organ damage characteristic of sickle cell disease. If so, novel therapeutic approaches might be of value.