Ocular radiation exposure is negligible in normal volume endourological practice

INTRODUCTION

The annual dose limit for radiation exposure to the eye has been reduced recently; the eye is widely recognised as one of the most radiosensitive tissues in the body. There is minimal good quality research as to the radiation dose that the eye receives during endourological surgery and this study aimed to address this.

METHODS

A prospective study was performed over an 8-month period at a single large teaching hospital in the UK. Three index procedures were included: ureteric stent insertion, ureteroscopy (URS) and percutaneous nephrolithotomy (PCNL). Surgeons wore a dosimeter on the glabella with fluoroscopy time (FT) and dose area product (DAP) recorded for each case.

RESULTS

A total of 404 procedures were included (247 URSs, 150 ureteric stent insertions and 7 PCNLs). Dosimeters were worn by ten surgeons. Mean FTs (URS 20.56s; ureteric stent 18.96s; PCNL 360.67s) and mean DAP (URS 100.82cGy/m2, ureteric stent 119.82cGy/m2 and PCNL 1121.62cGy/m2) were identified with significant intersurgeon variability. No surgeon had a total dosimeter dose >0.00mSv.

CONCLUSIONS

The International Commission on Radiological Protection recently reduced the yearly eye dose limit from 150 to 20mSv. Cataractogenesis is no longer considered a typical deterministic effect, with a threshold level below which no effect occurs. Even in higher volume centres, these annual limits are unlikely to be reached. Lead glasses may be considered for surgeons and radiologists with the highest exposure but, for the majority, ocular radiation exposure is negligible.

A comparison of S.T.O.N.E nephrolithometry scoring system, Guy's stone score, and Seoul National University Renal Stone Complexity (S-ReSC) in predicting mini-PCNL stone-free rate

The main goal of the study is to evaluate the three stone scoring systems (S.T.O.N.E nephrolithometry scoring system (STONE), Guy's stone score (GSS) and Seoul National University Renal Stone Complexity (S-ReSC)) for the stone-free rate (SFR) of mini-PCNL. We retrospectively analyzed 72 patients who received mini-PCNL from February 2018 to October 2020. The SFR, complication rates, hospitalization days and recurrence rates were analyzed using three stone scoring systems. The result showed statistical significance in the association between scoring system and stone-free (STONE: OR 95%CI 0.409 (0.221-0.759), p = 0.0045; S-ReSC OR 95%CI 0.633 (0.401-0.999), p = 0.0497), but not GSS (OR 95%CI 0.776 (0.397-1.516), p = 0.4581). After adjusting the potential confounding factors, the area under curve (AUC) of STONE, GSS, and S-ReSC was 0.86, 0.78, and 0.81, respectively, and Akaike information criterion (AIC) of STONE, GSS, and S-ReSC was 64.65, 74.89, and 69.92, respectively. The accuracy rate of STONE, GSS, and S-ReSC was 0.81, 0.75, and 0.79, respectively. There was no statistically difference of predicting stone recurrence (p = 0.46, 0.53, 0.86), complications (p = 0.74, 0.51, 0.16) and hospitalization days (p = 0.77, 0.86, 0.87) in STONE, GSS, and S-ReSC, respectively. In conclusion, both the STONE and S-ReSC stone scoring systems are viable for predicting the SFR following mini-PCNL, especially after variable adjustment with the STONE system demonstrating superiority over S-ReSC.

Dual-Energy Computed Tomography Applications in the Genitourinary Tract

By virtue of material differentiation capabilities afforded through dedicated postprocessing algorithms, dual-energy CT (DECT) has been shown to provide benefit in the evaluation of various diseases. In this article, we review the diagnostic use of DECT in the assessment of genitourinary diseases, with emphasis on its role in renal stone characterization, incidental renal and adrenal lesion characterization, retroperitoneal trauma, reduction of radiation, and contrast dose and cost-effectiveness potential. We also discuss future perspectives of the DECT scanning mode, including the use of novel contrast injection strategies and photon-counting detector computed tomography.

Renal cell carcinoma in a patient with staghorn stones: A case report

INTRODUCTION AND IMPORTANCE

Staghorn stone fills the renal pelvic and two or more branches of renal calyces. The incidence of staghorn stones is between 10 and 20 % of all urinary tract stones. We report the case of a man with right staghorn stones and renal mass who underwent right radical nephrectomy with pathology anatomy result of renal cell carcinoma (RCC).

CASE PRESENTATION

A 56-year-old man came with a complaint of right flank pain for two months. Physical examination is within normal limits, but an abdominal CT scan revealed a staghorn stone with enhancing mass in the upper pole of the right kidney. Patient subsequently underwent right radical nephrectomy. Pathology examination revealed RCC.

CLINICAL DISCUSSION

The presence of kidney stones in renal malignancy is rare. Kidney stones can be a risk factor for renal cell malignancy, and renal cell malignancies can cause urinary stasis, making it a risk factor for kidney stones. A study conducted by Nugroho and colleagues concluded that renal and caliceal biopsy should be considered in large and chronic renal stone due to potential experiencing kidney malignancy in patient with renal stone. Therefore, early diagnosis and definitive can be carried out.

CONCLUSION

Kidney stones and malignancy are rarely found. Renal pelvis, and caliceal wall biopsy should be considered in chronic and large renal stone, especially staghorn stone in patient that did not have any signs of malignancy on CT scan. Treatment in such case is focused on the oncological outcome. Therefore, radical nephrectomy is the treatment of choice.

Efficacy and safety of various endosurgical procedures for management of large renal stone: a systemic review and network meta-analysis of randomised control trials

Urolithiasis is the most common benign urological health condition. It has contributed sizeable burden of morbidity, disability, and medical health expenditure worldwide. There is limited high level of evidence on the efficacy and safety of treatment options of large renal stones. This network meta-analysis has examined the effectiveness and safety of various large renal stone management strategies. Systematic review and network meta-analysis (NMA) study design was employed to summarize comparative randomized controlled trials on humans with a diagnosis of renal stone larger than or equal to 2 cm in size. Our searching strategy was based on the Population, Interventions, Comparison, Outcomes, and Study (PICOS) approach. Medline via PubMed, Embase, Google scholar, SCOPUS, Science Direct, Cochrane library, Web of Science, and ClinicalTrials.gov were searched from inception to March 2023 to find eligible articles. Data extraction, screening, selection and risk of bias assessment were conducted by two independent reviewers. We found ten randomised control trials which consists 2917 patients, nine of them were labeled as low risk and one article was high risk. This network meta-analysis found that SFR was 86% (95% CI 84-88%) for Mini-PCNL, 86% (95% CI 84-88%) for standard PCNL, 79% (95% CI:73-86%) for RIRS, and 67% (95%CI:49-81 for staged URS for management of large renal stone. Overall complication rate was 32% (95% CI 27-38%) for standard PCNL, 16% (95% CI 12-21%) for Mini-PCNL, and 11% (95% CI 7-16%) for RIRS. Mini-PCNL (RR = 1.14 (95% CI 1.01-1.27) and PCNL (RR = 1.13 (95% CI 1.01-1.27)) were statistically associated with a higher SFR compared to RIRS. The pooled mean hospital stays were 1.56 days (95% CI 0.93-2.19) for RIRS, 2.96 days (95% CI 1.78-4.14) for Mini-PCNL, 3.9 days (95% CI 2.9-4.83) for standard PCNL, and 3.66 (95% CI 1.13-6.2) for staged URS. Mini-PCNL and standard PCNL were the most effective treatment options with significant morbidity and length of hospital stay, while RIRS was the safest management option with acceptable SFR, low morbidity, and short hospital stay.

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.

Ureteropelvic junction obstruction and renal calculi: Simultaneous treatment by robot-assisted laparoscopic pyeloplasty and transcutaneous retrograde flexible ureteroscopy. Technique description and early outcomes

BACKGROUND

Ureteropelvic junction obstruction (UPJO) and renal calculi are associated in 20 to 30% of cases and treatment is mandatory. The simultaneous surgical management is a therapeutic challenge that is still a source of controversy. We describe our technique combining robot-assisted laparoscopic pyeloplasty and transcutaneous retrograde flexible ureteroscopy (fURS), assessing the feasibility of simultaneous treatment through an original technique.

METHODS

This single centre series reports our initial experience with 12 patients. From January 2014 to September 2018, 12 patients underwent robot-assisted laparoscopic pyeloplasty with simultaneous fURS for UPJO and renal calculi. Mean age was 46 years (24-68). 92% had multiple renal stones and the mean cumulative stone diameter was 31,3mm. Robot-assisted pyeloplasty was performed with peroperative transcutaneous retrograde fURS through a ureteral access sheath introduced in an incision on the bassinet through a subcostal trocar. Stone extraction was performed using a basket.

RESULTS

All patients underwent surgery successfully, achieving UPJ repair and complete stone extraction. Mean operating time was 92,5min (85-110). All reported Clavien-Dindo complications were grade 1. Non-contrast enhanced abdominal CT performed 1 month after surgery confirmed the absence of residual stones in all patients. Mean follow-up time was 10 months with no recurrence of UPJO.

CONCLUSION

This small series confirms the feasibility with good surgical results of concomitant robot-assisted laparoscopic pyeloplasty and transcutaneous retrograde fURS stone extraction. No major complications were observed. This technique is easily reproducible but requires 2 experienced urologists to be achieved in a contained operative time.

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.

Are the current nomograms sufficient to predict shockwave lithotripsy outcomes?

INTRODUCTION AND OBJECTIVES

To investigate factors affecting SWL outcomes, validate three current nomograms (Kim JK, Triple D and S3HoCKwave) and compare the predictive ability of the nomograms for SWL outcomes in upper urinary tract stones.

PATIENTS AND METHODS

Medical records of patients with renal and proximal ureteral stones treated with SWL between March 2013 and October 2020 were retrospectively reviewed. Factors affecting SWL success were analyzed with multivariate logistic regression analysis and the three predictive scoring systems compared with the area under the curve (AUC).

RESULTS

A total of 580 patients were included in our study. The overall stone free rate was 61% and 144/580 patients (24.8%) were stone free after one session. In multivariate logistic regression analysis, stone location at upper calyx (OR:2.988; 95%Cl: 1.350-6.612; p = 0.007), middle calyx (OR:3.036; 95%Cl: 1.472-6.258; p = 0.003), and lower calyx (OR:2.131; 95%Cl: 1.182-3.839; p = 0.012), as well as number of stones (OR:1.663; 95%Cl: 1.140-2.425; p = 0.008), maximum diameter of stone (OR:1.156; 95%Cl: 1.098-1.217; p < 0.001) and maximum Hounsfield Unit (OR:1.001; 95%Cl: 1.001-1.002; p < 0.001) were independent risk factors of SWL failure. The AUCs of the Kim JK, Triple D and S2HoCKwave scores for predicting SWL success were 0.678, 0.548, and 0.626 respectively.

CONCLUSIONS

Stone location, number, maximal diameter, and maximum HU were independent predictive factors for SWL outcome in the treatment of upper urinary tract stones. Current nomograms, "Kim JK nomogram", "Triple D score" and "S3HoCKwave score" can predict treatment success after SWL, but all of them have poor discrimination according to AUC analysis.

A comparison among RIRS and MiniPerc for renal stones between 10 and 20 mm using thulium fiber laser (Fiber Dust): a randomized controlled trial

PURPOSE

We performed a prospective randomized comparison among Retrograde IntraRenal Surgery (RIRS) and MiniPerc (MP) for stones between 10 and 20 mm to evaluate outcomes with the same laser device: Fiber Dust.

METHODS

Patients with a single renal stone between 10 and 20 mm were randomized to RIRS (Group A) versus MP (Group B). Exclusion criteria were age < 18 or > 75, presence of acute infection, coagulation impairments, cardiovascular or pulmonary comorbidities. In both groups, the Fiber Dust laser was used. A CT scan after 3 months was performed. A negative CT scan or asymptomatic patients with stone fragments < 3 mm and a negative urinary culture were the criteria to assess the stone-free status. A statistical analysis was carried out to assess success, complication and retreatment rates and need for auxiliary treatments.

RESULTS

Between January 2021 and January 2022, 186 patients were enrolled (90 in Group A and 96 in Group B). Mean stone size was 15.8 mm and 14.9 mm in Group A and B, respectively (p = 0.23). The overall stone-free rate (SFR) was 73.3% for Group A and 84.4% for Group B. A higher SFR was reached for upper calyceal stones in Group A (90.4%) lower calyceal stones in Group B (91.6%). Retreatment rate (p = 0.31) and auxiliary procedure rate (p = 0.18) were comparable. Complication rate was 5.5% and 5.2% for Groups A and B, respectively.

CONCLUSIONS

RIRS and MP are both effective to obtain a postoperative SFR with Fiber Dust. According to the stone position one treatment is superior to the other one.

Open surgery versus percutaneous nephrolithotomy for management of staghorn calculi

BACKGROUND

For urologists, treating staghorn stones remains a difficult challenge. Various studies have evaluated the results of percutaneous nephrolithotomy (PCNL) and open surgery in different populations but these results were controversial. Here, we aimed to compare and evaluate the results of open surgery and PCNL in the treatment of staghorn stones.

METHODS

This retrospective descriptive study was performed to compare the results of open surgery and PCNL in the treatment of staghorn stones in 2013-2021. A total of 360 participants were studied among the population. Demographic data of patients including age, gender, and comorbidities were obtained. We assessed variables including type of stone, serum creatinine, degree of hydronephrosis, and urine culture before the operation. All participants in our study were informed of the two surgical alternatives.

RESULTS

The mean length of hospital stay in PCNL patients was 3.88 ± 1.76 and in open surgery patients was 5.858 ± 2.12 (P = 0.003). In 30 patients (13.9%) in the PCNL group and 27 patients (18.8%) in the open surgery group, bleeding necessitating blood transfusion was the only intraoperative complication. 309 patients (85%) had no residual stones at the time of discharge from the hospital, which was 81.9% (177 cases) in patients treated with PCNL and 91.6% (132 patients) in the open surgery group (P > 0.05).

CONCLUSION

Staghorn calculi can be managed effectively with open surgery or PCNL. Given the reduced postoperative complication rate and higher stone-free rate, we believe open surgery is better technique for complicated staghorn stones with a high burden.

Outcomes and lessons learnt from practice of retrograde intrarenal surgery (RIRS) in a paediatric setting of various age groups: a global study across 8 centres

PURPOSE

To analyse and report the practice, outcomes and lessons learnt from a global series of retrograde intrarenal surgery (RIRS) in a paediatric multicentre series.

METHODS

A retrospective review of anonymized pooled data gathered globally from 8 centres in paediatric patients (≤ 18 years of age) who had renal stones and underwent RIRS from 2015 to 2020 was performed. Patient demographics, perioperative parameters, stone characteristics, complications and stone-free rate (SFR; defined as endoscopically stone free and/or residual fragments < 2 mm on follow up imaging) were analysed. The cohort was stratified into 3 groups by age: < 5 years (Group A), 5-10 years (Group B) and > 10 years (Group C). Overall, post-operative complication rate was 13.7%. Chi-square comparisons were used for categorical variables; analysis of variance (ANOVA) or Kruskal-Wallis tests were used for continuous variables.

RESULTS

314 patients were analysed. The mean age was 9.54 ± 4.76 years. Groups A, B and C had 67 (21.3%), 83 (26.4%) and 164 (52.2%) patients, respectively. Mean stone size was 10.7 ± 4.62 mm. Pre-stenting was performed in 155 (49.4%) of patients, ureteral access sheaths (UAS) was used in 54.5% of patients with majority (71%) utilizing holmium laser for stone fragmentation. All complications were minor (Clavien-Dindo grade 1 and 2). SFR was 75.5%.

CONCLUSIONS

RIRS is acceptable as a first-line intervention in the paediatric population with reasonable efficacy and low morbidity. Complications are slightly higher in patients < 5 years of age, which should be taken into account while counselling patients.

Hem-o-Lok clip migration into renal pelvis and stone formation as a long-term complication following laparoscopic pyelolithotomy: a case report and literature review

BACKGROUND

Hem-o-Lok clips (HOLCs) are widely used in minimal access urological operations due to the advantage of vascular control and suture stabilization. In rare cases, however, they can develop problems themselves. Migration of HOLCs into the collecting system is a fairly rare complication after laparoscopic pyelolithotomy. To date, only two cases were reported in the literature.

CASE PRESENTATION

This article describes a case of 51-year-old man with a complaint of left flank pain. He had a medical history of ipsilateral retroperitoneal laparoscopic pyelolithotomy at another hospital 8 years ago. Non-contrast CT scan demonstrated a renal stone in the left ureteropelvic junction complicated by mild hydronephrosis. A straight foreign body was found near the renal pelvis, with part of it wedging into renal pelvic wall. A percutaneous nephrolithotomy (PNL) was performed for this patient. After some fragmentation, a HOLC was found in the kernel of the stone. With an alligator plier, the clip was totally removed out of the collecting system. The postoperative period and follow-up were uneventful.

CONCLUSIONS

HOLC migration into renal pelvis is a rare complication following laparoscopic pyelolithotomy. It could act as nidus for stone formation under extended exposure to urine. Using HOLCs to stabilize the anastomotic suture near renal pelvis should be avoided to prevent this complication. Instead, knotting is a better choice under such condition. The secondary calculi and dislodged HOLCs can be removed through PNL by an alligator plier after laser lithotripsy.

The association of dental pulp stones to cardiovascular and renal diseases: A systematic review and meta-analysis

BACKGROUND

Pulp stone (PS) is a dystrophic calcification in the tooth's pulp chamber and was suggested in the literature to be associated with other calcifications in the body. This study aimed to investigate the association of PS to cardiovascular diseases (CVD) and renal stones (RS).

METHODS

Three databases were searched until June 2021 in addition to manual searching of Google Scholar and grey literature. Original studies were only included and critically appraised using an adapted version of the Newcastle-Ottawa scale. The odds ratio (OR) effect measure was calculated using the Mantel-Haenszel statistical test (95% confidence interval [CI]) to investigate the association of PS with CVD and or RS (p-value ˂ 0.05).

RESULTS

The database search identified 4933 studies, and 19 studies were finally included. The risk of bias was low in thirteen studies, moderate in four studies, and high in two studies. The meta-analysis of the moderate-and-low risk of bias studies revealed a significant association between PS and CVD (OR 3.35, 95% CI 1.91-5.89, P < 0.001, I² = 65%), but no association was found between PS and RS. The results also revealed an association between PS and CVD in patients older than 40 (OR 8.78, 95% CI 3.64-21.17, P < 0.001, I² = 0%).

CONCLUSIONS

The current study results showed an association between PS and CVD, but no association was found between PS and RS. PS in patients younger than 40 years, compared to older patients (> 40 years), was associated with CVD.

The Trends of Urolithiasis Therapeutic Interventions over the Last 20 Years: A Bibliographic Study

Introduction: The clinical and economic burden of kidney stones is a challenge for the healthcare system. There is a limited bibliometric project exploring the literature trends on 'urolithiasis' and its related management. Methods: A systematic review was conducted to discover the related abstracts regarding each specific issue, investigated year by year from May 2000 to May 2020 (20 years). To make an effective comparison, the statistics resulting from every single study were allocated to two 10-year periods: period 1 (2000 to 2010) and period 2 (2010 to 2020). In this study, we included all English language articles, all non-English articles with English abstracts, and studies in which interventions were used for stone removal, including laser technology. Also, we excluded the studies without a published abstract, an intervention or a laser, animal and in vitro studies, and case reports. Results: These articles are about ureteroscopy (URS) (n=10360, 33.45%), percutaneous nephrolithotomy (PCN) (n =10790, 34.84%) and extra-corporeal shockwave lithotripsy (ESWL) (n=9846, 31.76%). When evaluating the two time periods, there were 9912 studies available in period one, which increased by ×2.12 times (112.71% rise) to 21084 studies in period two (P = 0.001). The increase was 133%, 103.51%, and 70.4% for URS, PCN, and SWL respectively. A total of 855 studies on Laser application via URS were published on PubMed over a 20-year period. There was an increasing trend toward using laser application via URS over the study period. Also, there were 230 articles published in period one, which increased by nearly 2.71 times (rise of 171.73%) to 625 papers in period two (P < 0.001). There was an increasing trend toward using laser application via PCN; 126 papers were published in period one, which increased by nearly 3.05 times (rise of 205.5%) to 385 papers in period two (P = 0.002). Conclusion: The minimal invasive interventions for stone removal, including URS and PCN, increased dramatically in the last decade, and the use of lasers in stone treatment increased significantly in the last decade.

The effect of stone and patient characteristics in predicting extra-corporal shock wave lithotripsy success rate: A cross sectional study

Introduction

We determine the effect of patient characteristics (age, sex, and body mass index BMI) and stone characteristics (density, location, and size) by non-contrast computed tomography of the kidneys, ureters, and bladder (CT-KUB) in predicting the success of extracorporeal shock wave lithotripsy (ESWL) in the treatment of kidney and ureteric stones. We present this study to further enrich the knowledge of physicians towards the effect of different patient characteristics upon predicting extra-corporal shock wave lithotripsy success rates.

Methods

We evaluated 155 patients who received ESWL for renal and ureteric stone measuring 3–20 mm (mm), over a 3-month period. The stone size in millimeters, density in Hounsfield units (HU) and its location was determined on pre-treatment CT-KUB. ESWL was successful if post-treatment residual renal stone fragments were ≤3 mm and for ureteric stones should be totally cleared.

Results

The overall success of ESWL treatment was observed in 65.8% of the 155 patients. There was no significant difference seen when the effect of patients age, sex and BMI were studied with ESWL outcome with P values were 0.155, 0.101 and 0.415 respectively. Also, stone location either in the kidney or ureter has no statistically significant effect on ESWL response rate. while stone density and size determined on CT KUB have statistically significant effect on the success rate of ESWL with a P-value of 0.002 and 0.000 respectively.

Conclusions

This study shows that determination of stone density and stone size on CT KUB pre ESWL can help to predict the outcome of ESWL. We propose that stone density <500 HU and stone size < 5 mm are highly likely to result in successful ESWL.

•

Previous studies have reported a wide variation of ESWL success rate ranging from 46% to 91%.

•

Failure of ESWL results in unnecessary exposure of renal parenchyma to shock waves and complications like renal hematoma.

•

Increasing Efforts have been made to determine factors that predict ESWL outcome and improve patients' selection.

Counter-Irrigation as a Novel Technique versus the Standard Technique in Percutaneous Nephrolithotomy: A Prospective Randomized Trial

OBJECTIVE

This study aimed to evaluate the efficacy of our counter-irrigation technique versus the standard technique in percutaneous nephrolithotomy (PCNL) by assessment of the stone-free rate after the procedures and its safety in terms of comparing the intraoperative time, Hb deficit, blood transfusion, length of hospital stay, auxiliary procedures, and perioperative complications with that of the standard one.

METHODS

This prospective randomized trial was conducted on patients with renal stone 2-3 cm in diameter without contraindications to PCNL. The patients were randomized into group A in which the counter-irrigation technique has been performed and group B who were managed by the standard technique. The preoperative characteristics including demographic data and stone parameters were compared between both groups. The primary outcome was the stone-free rate assessed by noncontrast spiral CT after 3 months. The secondary outcome included intraoperative time, Hb deficit, blood transfusion, hospital stay, auxiliary procedure required, and rate of complications.

RESULTS

Forty-eight patients were included in this study. Overall, no significant difference was observed between both groups regarding preoperative characteristics, Hb deficit, and complication rate. Operative time was significantly shorter in group B (p = 0.001). None of our patients required blood transfusion. The stone-free rates at 3 months were significantly better in group A (95% for group A and 70% for group B, p = 0.04).

CONCLUSIONS

Our results indicate that our counter-irrigation technique has lower stone migration with subsequent significantly better stone-free rate versus the standard technique. We can recommend this technique as a potentially valid option for cases with large stone burden when the access to the upper calyx is feasible to minimize significant residual fragments.

Double-Sheath Vacuum Suction Minimally Invasive Percutaneous Nephrolithotomy for Management of Large Renal Stones

OBJECTIVES

This study aimed to describe a novel double-sheath vacuum suction minimally invasive percutaneous nephrolithotomy (mini-PCNL) to overcome the deficiencies of the conventional procedure.

PATIENTS AND METHODS

Between March 2019 and December 2019, 65 patients (37 males and 28 females) with a mean age of 41 years (range 23-69) underwent mini-PCNL with double-sheath vacuum suction. It consisted of an F20 Y-shaped sheath as an outer sheath and an F16 Y-shaped sheath as an inner sheath, in which the inner sheath was longer than the outer sheath. The oblique arm of the outer sheath and the inner sheath was connected to the perfusion inflow and the vacuum suction, respectively. A 550-μm holmium-YAG laser was introduced for stone fragmentation through the working channel of the mini-nephroscope, which was no longer connected to the perfusion fluid.

RESULTS

All procedures were successful. Mean operation time was 50.2 min (range 39-83). Mean hemoglobin decrease was 5.2 g/L (range 1.0-15.5), and no patient needed a blood transfusion. One patient (1.5%) with low fever (<38°C) at day 1 had returned to normal at day 2 without administration of antibiotics. There were no Clavien grade 2-4 complications. Mean postoperative hospital stay was 2.4 days (range 2-6). The initial stone-free rate of PCNL was 81.53% (53 of 65 patients). One month after surgery, the final stone-free rate increased to 90.77% (59/65 patients).

CONCLUSIONS

The double-sheath vacuum suction mini-PCNL is a safe and effective modality for large renal stones, which might increase the efficiency of stone extraction with low intrapelvic pressure.

A rare case scenario

Introduction

Genitourinary trauma secondary to a gunshot wound is uncommon as it only occurs in about 10% of cases. We present a case of a gentleman who suffered a gunshot wound to the kidney.

Presentation of case

A 28 year old man presented with irritative lower urinary tract symptoms (LUTs) since three months. The medical history was irrelevant. He is known case of neurogenic bladder maintained on regular clean intermittent catheterization (CIC). He has history of gunshot to the back since few years that resulted in spinal injury. CTUT showed retained bullet inside the right kidney that look alike hyperdense renal stone, Moreover, multiple vesical stones. The vesical stones were treated with cystolitholapaxy. Given that the patient is asymptomatic, conservative management for the retained right renal bullet is the feasible option.

Discussion

Based on the ASST classification, renal gunshot injury results in a grade IV injury. Abdominal exploration was reserved only in selected scenarios. Gunshot injuries to the kidney are commonly associated with thoracic and abdominal injuries. Gunshot injuries may be caused by low-velocity or high-velocity bullets. Given the paucity of cases reported in the literature, it is not obvious what is the optimum management of such patients with a retained renal bullet? We present the radiological findings and a clinical case summary as well for those who have Grade IV kidney injury and retained bullet managed conservatively.

Conclusion

Retained renal bullet post gunshot injury to the back is unusual presentation. A characteristic star-like pattern produced by lead shots and not by “stone,” consisting of plastic detonating cap will aid the urologist to differentiate retained renal bullet from renal stone. In such scenario, asymptomatic renal bullet look alike renal stone doesn't necessitate treatment.

Percutaneous extraction of big kidney stone without fragmentation: The novel technique in percutaneous nephrolithotomy (EN BLOC PCNL)

PCNL is gold standard treatment of pelvis stone more than 2 cm. Since 1970 that PCNL was introduced, multiple methods including mini PCNL, Lap assisted PCNL etc. were used to increase the efficacy and decrease the complications of PCNL in different patients. We describe a new method of PCNL for the first time for extracting 7 cm renal stone without fragmentation, and we called it EN BLOC PCNL. Our technique had no complication and caused lower operative time.

Double-sheath vacuum suction versus vacuum-assisted sheath minimally invasive percutaneous nephrolithotomy for management of large renal stones: single-center experience

PURPOSE

To compare double-sheath vacuum suction minimally invasive percutaneous nephrolithotomy (DS-mini-PCNL) with vacuum-assisted mini-PCNL (VS-mini-PCNL) and to better define the potential benefits of DS-mini-PCNL.

METHODS

Between July 2019 and May 2020, 117 patients with large radiopaque renal stones underwent mini-PCNL. Of these, 63 underwent DS-mini-PCNL and 54 underwent VS-mini-PCNL. For VS-mini-PCNL, a F20 Y-shaped sheath was used and the oblique arm of the sheath was connected to the vacuum suction. For DS-mini-PCNL, the oblique arm of a F20 Y-shaped sheath (the outer sheath) and a F16 Y-shaped sheath (the inner sheath) was connected to the perfusion inflow and the vacuum suction, respectively. A 550-μm holmium-YAG laser was used for stone fragmentation.

RESULTS

Compared with VS-mini-PCNL group, DS-mini-PCNL group had significantly shorter operative time (35.78 ± 7.77 min vs. 44.56 ± 13.19 min; P = 0.000) and significantly lower fever rate (1.6% vs. 11.1%; P = 0.048). It was not significantly different between the two groups despite the higher initial stone-free rate seen for DS-mini-PCNL group relative to VS-mini-PCNL group (87.7% vs. 81.5%, P = 0.346). Auxiliary procedure rates were 4.8% (three patients) in DS-mini-PCNL group and 16.7% (nine patients) in VS-mini-PCNL group, with a significant difference (P = 0.034). The difference in the final stone-free rate between the two groups was rendered insignificant (93.8% vs. 89.1%, P = 0.510).

CONCLUSIONS

DS-mini-PCNL is a safe and effective modality for large renal stones, which could increase the efficiency of stone extraction and decrease infectious complications compared with VS-mini-PCNL.

Can obstructive urolithiasis be safely excluded on contrast CT? A retrospective analysis of contrast-enhanced and noncontrast CT

PURPOSE

The aim of this study was to determine if contrast-enhanced CT can safely exclude obstructive urolithiasis in patients with flank plain. We performed a retrospective cohort analysis to compare the negative predictive values of contrast-enhanced and non-contrast CTs for the detection of obstructing urolithiasis.

METHODS

Through report analysis, we identified all non-contrast and contrast-enhanced CT examinations of the abdomen and pelvis performed on adult patients in the emergency department at a single, multi-site academic medical institution in 2017 with an indication of flank pain. The prevalence of obstructive urolithiasis in each group was calculated. We subsequently analyzed 200 consecutive studies from each of these groups (reported negative for obstructive urolithiasis) for negative predictive value calculation. Follow up abdominal imaging within 7 days from original presentation was used as a reference standard for analysis.

RESULTS

In the noncontrast group, 1 study out of 200 was false negative (negative predictive value = 99.5%). In the contrast-enhanced group, there were no false negatives (negative predictive value = 100%). The prevalence of obstructive urolithiasis was 44.0% (351/797) in the noncontrast group and 18.7% (86/459) in the contrast-enhanced group.

CONCLUSION

Our results suggest that contrast-enhanced CT can safely exclude obstructing ureteral calculi in the setting of acute flank pain. This finding is of clinical relevance given the inherent benefit of IV contrast in diagnosing abdominopelvic pathology.

Large spontaneous steinstrasse: Our experience and management issues in tertiary care centre

BACKGROUND

Steinstrasse, is described as array of stone pieces in the ureter following extracorporeal shock wave lithotripsy (SWL). It is well-recognized, transient event. Steinstrasse clears spontaneously, however about 6% require intervention. Spontaneous steinstrasse without prior history of SWL is a rare occurrence and only few case reports are published in literature. Objective of the study was to assess the aetiology and management issues of large spontaneous steinstrasse in our centre.

METHOD

From February 2017 to March 2019, 684 patients underwent SWL for renal or ureteric stones. Twenty-eight patients presented with steinstrasse of which nine patients had no prior history of SWL. Detailed clinical profile and management issues have been discussed.

RESULT

Among the nine patients of spontaneous steinstrasse, there were six males and three females. Mean age of the patients was 39 years (±13 years SD). Bilateral large spontaneous steinstrasse was seen in one out of nine patients. Seven patients had associated renal stones. Five patients presented with obstructive uropathy and three out of them had urosepsis as initial presentation. Ureterolithotomy and percutaneous nephrolithotomy were commonly performed procedures for stone clearance. Metabolic work was done in all cases in follow up period. Three patients had hypercalciuria and hypocitraturia suggestive of renal tubular acidosis.

CONCLUSION

Large spontaneous steinstrasse is uncommon case scenario. It can be subtle in presentation and yet have significant patient consequence in terms of renal function and infection. Prompt management is essential to preclude permanent loss of renal function. Metabolic evaluation is indispensable in such cases.

Antibiotic administration for negative midstream urine culture patients before percutaneous nephrolithotomy

To investigate how to administrate antibiotics for negative midstream urine culture (UC-) patients prior to percutaneous nephrolithotomy (PCNL), we retrospectively analyzed UC-patients receiving 0 or 3 days of cefuroxime prior to PCNL between July 2017 and May 2020. Patients were further divided into four groups (Group1A = urine with positive both nitrite and white blood cell (N + WBC +) and 0-day pre-operative cefuroxime; Group1B = N + WBC + and 3-day cefuroxime; Group2A = N - WBC + and 0-day cefuroxime; Group2B = N - WBC + and 3-day cefuroxime). All patients routinely received a dose of cefuroxime 30 min prior to the surgery. In addition, Group1B were matched to the Group1A; Group2B were matched to the Group2A at a 1:1 ratio regarding stone burden, the degree of hydronephrosis, stone hardness, age and sex in a sequential order. A total of 560 patients were included (Group1A = 72; Group1B = 72; Group2A = 208; Group2B = 208). The baseline characteristics were equally distributed between the matched-pair groups. Compared to Group1B, Group1A had a significantly higher incidence of SIRS, fever, urosepsis requiring only additional antibiotics, and an increased postoperative hospitalization stay. Compared to Group2B, Group2A had similar rate of infectious complications. In addition, Group1B was associated with a significantly lower rate of positive pelvic urine culture (PUC +) than that of Group1A; whereas, there was similar rate of PUC + between Group2A and Group2B. UC-patients with N + WBC + should be treated with extended period of antibiotic administration, and a single dose of prophylactic antibiotic was sufficient for UC-patients with N - WBC + prior to PCNL. Despite UC, it is suggested to stratify pre-operative antibiotics tailored to individual patients to optimize its application.

Can Dual Energy CT with Fast kV-Switching Determine Renal Stone Composition Accurately?

RATIONALE AND OBJECTIVES

To determine whether a single source computed tomography (CT) system utilizing fast kV switching and low dose settings can characterize (diameter and chemical composition) renal stones accurately when compared infrared spectroscopy.

MATERIALS AND METHODS

The chemical composition of 15 renal stones was determined using Fourier transform infrared spectroscopy. The stones were inserted into a porcine kidney and placed within a water tank for CT scanning using both fast kV switching dual energy and standard protocols. Effective atomic number of each stone was measured using scanner software. Stone diameter measurements were repeated twice to determine intra-rater variation and compared to actual stone diameter as measured by micro CT.

RESULTS

The chemical composition of three stones (one calcium phosphate and two carbonite apatite) could not be determined using the scanner software. The composition of 10/12 remaining stones was correctly identified using dual energy computed tomography (83% absolute agreement; k = 0.69). No statistical difference (p = 0.051) was noted in the mean stone diameter as measured by clinical CT and micro CT.

CONCLUSION

Dual energy computed tomography using fast kV switching may potentially be developed as a low dose clinical tool for identifying and classifying renal stones in vivo supporting clinical decision-making.

Effectiveness of ultrasound-guided shockwave lithotripsy and predictors of its success rate in pediatric population: A report from a national reference center

OBJECTIVE

Shockwave lithotripsy (SWL) remains a well-established treatment modality for many of the pediatric renal and ureteral stones. Repeated SWL sessions carry limitations due to the use of general anesthesia and X-ray radiation. The objective of our study was to evaluate stone-free rate (SFR) of 1-session of SWL for the management of pediatric renal and ureteral stones less than 2 cm performed exclusively under ultrasound guidance and identify factors influencing its success.

METHODS

The study utilized a retrospective cohort design including 124 consecutive pediatric patients with 133 renal and ureteral stones less than 2 cm whom SWL was performed in the period of January 2008 to December 2019. SWL procedures were performed by one expert surgeon in a single, national reference center, exclusively under ultrasound guidance using Modulith® SLK lithotripter. Follow-up was performed in post-SWL 2nd, 4th, 12th weeks and 6 months.

RESULTS

The mean age of the children was 10 years (SD = 6.0) and the mean stone size was 10.4 mm (SD = 3.6 mm). Sedation type of anesthesia was used in 80 patients (64.5%). No major complication was developed, and no ureteral stenting was required in any of the patient following SWL. The SFR following 1-session of SWL was 88.0% at 12-week. Younger age (P = 0.002), sedation type of anesthesia (P = 0.001) and presence of radiolucent stones (P = 0.033) significantly improved post-SWL early stone clearance on univariate analysis, the latter being the only significant factor according to final model (P = 0.031).

CONCLUSIONS

Ultrasound-guided SWL represents a safe and effective method for the management of both renal and ureteral stones in children. The SFR following 1-session of SWL at 12-weeks was achieved in 88.0%, the overall success rate after all SWL sessions reaching 91.7%. A higher success rate was observed in children harboring radiolucent stones.

Effect of parathyroidectomy on renal stone recurrence

Parathyroidectomy (PTX) is routinely performed in hypercalciuric renal stone patients with primary hyperparathyroidism (PHPT). However, some data indicate a persistent stone activity following PTX, raising the issue of the link between PHPT and stone disease. We performed an observational study on 30 renal stone patients diagnosed with PHPT. Patients were selected among 1448 hypercalciuric patients referred in our department for a diagnostic evaluation. Patients with no parathyroid surgery or any biological follow-up were excluded. Clinical and biological data (including 24-h urine collection and a calcium load test) were collected before and within 12 months following surgery. Stone recurrence was evaluated by direct phone contact (median 43 months). Comparison of biological data before and after surgery showed a significant decrease of ionized calcium and serum parathyroid hormone after PTX. All stones contained calcium-dependent species such as carbapatite, brushite or dihydrate calcium oxalate. Urine saturation indexes and calciuria significantly decreased after surgery (from 9.9 to 5.9 mmol/d, p < 0.0001), but a persistent hypercalciuria was detected in 47% of patients. The other stone risk factors including diuresis stayed similar. Stone activity that was increasing (from 0.20-0.30 to 0.50-0.75/year) the 2 years before PTX, significantly decreased after surgery [0.05-0.15/year (p < 0.001)]. PTX in calcium-dependent renal stone formers with PHPT significantly decreases both stone recurrence and urine saturation indexes. However, PTX unmasked an underlying renal stone disease related to idiopathic hypercalciuria in half of patients with a remaining stone activity, testifying the need for patient's follow-up to prevent stone recurrence.

Urinary stone diagnosis. Morphologic and composition analysis

Analysis of urinary stones is an essential step in establishing the diagnosis and treatment of the stone patient. In fact, the need for an exhaustive study of the stones increases as the relationships between the type of stone and the etiological factors that predispose to this disease become evident. The enumeration (qualitative or quantitative) of the major components that make up the kidney stone (calcium oxalate monohydrate, calcium oxalate dihydrate, uric acid, calcium phosphates, cystine), which is obtained by the most commonly used analytical method, infrared spectroscopy (IR), is no longer enough to guide the urologist on the etiology of the disease. Only a detailed structural analysis and macro and micro components can provide key information on the etiology of the stone, and therefore, on the possible causes that have led to its formation. This study should conclude with a report that is provided to the Urologist. Obtaining this report involves a detailed study, sample by sample, which involves the systematic handling of stereoscopic microscopy, IR spectroscopy and scanning electron microscopy (SEM) with energy dispersive X-raymicroanalysis (EDAX).

Quality of life in patients with kidney stones

Patient reported outcome measures (PROMs) are essential to fully understand the impact of diseases and the effectiveness of treatment from a patient's perspective. Generic and disease-specific tools have been used to assess the impact of nephrolithiasis on patients' quality of life (QoL), as well as the impact of various treatment modalities. Additionally, various studies have investigated the factors that might determine the impact of the disease on the patients' QoL. Here were view the available knowledge on this nascent topic and highlight the need for extensive future research in this crucial area.

Challenges and management of laparoscopic treatment of pyonephrosis caused by calculi

Background

Calculous pyonephrosis is a disease characterized by infectious hydronephrosis associated with pyogenic destruction of the renal parenchyma, with complete or almost complete loss of renal function.

Methods

The clinical data of laparoscopic nephrolithotomy performed at Peking University People’s Hospital from May 2017 to June 2020 were analyzed retrospectively. Eight patients (2 men; 6 women) aged 27 to 65 years (average age, 45.8 years) were included. Among them, 7 patients were treated with retroperitoneal approach and 1 patient by transperitoneal approach. All patients had received more than one endoscopic lithotripsy before nephrectomy. Renal dynamic imaging and computed tomography revealed the absence of function in pyonephrosis before nephrectomy. General clinical data and perioperative data were recorded. All nephrectomies were performed by the same physician.

Results

Laparoscopic surgery was successfully performed in 7 patients; however, 1 patient underwent open surgery because of bleeding. The operation time, average operation time, and blood loss were 1.5–4.5 h, 3.4 h, and 100–1000 ml (average, 300 ml), respectively. The postoperative pathology showed inflammatory renal disease in 6 patients, xanthogranulomatous pyelonephritis in 1 patient, and high-grade urothelial cancer in 1 patient. The average postoperative hospital stay was 5.3 days. One patient had a Clavien–Dindo Grade IIIb complication (severe hematuria), which required laparotomy, and was found that there was bleeding of ureteral stump. None of the patients experienced poor healing of endoscopic wounds.

Conclusion

For patients with complicated calculous pyonephrosis, renal inflammation could not be effectively controlled, and renal function was seriously damaged. Thus, kidneys should be immediately resected. With laparoscopy, patients may recover quickly, but surgeons require enough experience when performing laparoscopy to achieve safety.

Tea and coffee consumption and pathophysiology related to kidney stone formation: a systematic review

OBJECTIVE

To explore the mechanisms behind the potential protective effect of coffee and tea consumption, regarding urinary stone formation, previously demonstrated in large epidemiological studies.

METHODS

A systematic review was performed using the Medline, Cochrane library (CENTRAL) and Scopus databases, in concordance with the PRISMA statement. English, French and Spanish language studies, regarding the consumption of caffeinated and decaffeinated coffee and tea, and the relationship to urinary stone formation were reviewed. Meta-analyses, systematic reviews, case reports and letters, unpublished studies, posters and comments abstracts were excluded.

RESULTS

As per the inclusion criteria, 13 studies were included in the final review. The major findings show that caffeine increases urinary excretion of calcium, sodium and magnesium, in addition to a diuretic action with consumption > 300-360 mg (approximately four cups of coffee). Together with other components of coffee, this beverage might have potential protective effects against the formation of urinary stones. Tea exerts many protective effects against stone formation, through the accompanying water intake, the action of caffeine and the effects of components with antioxidant properties.

CONCLUSION

Caffeine has a hypercalciuric effect, balanced partially by a diuretic effect which appears after consumption of large quantities of caffeine. The current available literature supports in general, a potentially protective role for tea against stone formation, mainly for green tea. Additional standardization in this field of research, through specification of tea and coffee types studied, and their respective compositions, is needed for further clarification of the relation between coffee, tea and urinary stones.

Mini Percutaneous Nephrolithotomy Is a Noninferior Modality to Standard Percutaneous Nephrolithotomy for the Management of 20-40mm Renal Calculi: A Multicenter Randomized Controlled Trial

BACKGROUND

High quality of evidence comparing mini percutaneous nephrolithotomy (mPNL) with standard percutaneous nephrolithotomy (sPNL) for the treatment of larger-sized renal stones is lacking.

OBJECTIVE

To compare the efficacy and safety of mPNL and sPNL for the treatment of 20-40mm renal stones.

DESIGN, SETTING, AND PARTICIPANTS

A parallel, open-label, and noninferior randomized controlled trial was performed at 20 Chinese centers (2016-2019). The inclusion criteria were patients 18-70 yr old, with normal renal function, and 20-40mm renal stones.

INTERVENTION

Percutaneous nephrolithotomy PNL was performed using either 18 F or 24 F percutaneous nephrostomy tracts.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome was the one-session stone-free rate (SFR). The secondary outcomes included operating time, visual analog pain scale (VAS) score, blood loss, complications as per the Clavien-Dindo grading system, and length of hospitalization.

RESULTS AND LIMITATIONS

The 1980 intention-to-treat patients were randomized. The mPNL group achieved a noninferior one-session SFR to the sPNL group by the one-side noninferiority test (0.5% [difference], p <  0.001). The transfusion and embolization rates were comparable; however, the sPNL group had a higher hemoglobin drop (5.2 g/l, p <  0.001). The sPNL yielded shorter operating time (-2.2 min, p = 0.008) but a higher VAS score (0.8, p <  0.001). Patients in the sPNL group also had longer hospitalization (0.6 d, p <  0.001). There was no statistically significant difference in fever or urosepsis occurrences. The study's main limitation was that only 18F or 24F tract sizes were used.

CONCLUSIONS

Mini mPNL achieves noninferior SFR outcomes to sPNL, but with reduced bleeding, less postoperative pain, and shorter hospitalization.

PATIENT SUMMARY

We evaluated the surgical outcomes of percutaneous nephrolithotomy using two different sizes of nephrostomy tracts in a large population. We found that the smaller tract might be a sensible alternative for patients with 20-40mm renal stones.

The effect of preoperative ureteral stenting in retrograde Intrarenal surgery: a multicenter, propensity score-matched study

Background

Stent placement before retrograde intrarenal surgery (RIRS) can theoretically expand the ureter to improve access and remove stones. The purpose of this study was to investigate the effect of preoperative ureteral stenting on access and surgery.

Methods

We retrospectively analyzed patients who underwent RIRS between January 2010 and December 2016 at multiple centers. The patients were divided into two groups based on whether or not a ureteral stent was inserted preoperatively. The characteristics of the stone (size, number, density, and location), the success rate of the access sheath placement, perioperative complications, operative times, hospitalization periods, the period for which the stents remained, postoperative urinary tract infection rates, stone-free rates, and additional treatment rates were analyzed.

Results

Overall, 727 patients were included in the study (113 were pre-stented and 614 were non-stented). The median stone size was 12.2 mm. The overall stone-free rate (SFR) was 85.8% for the pre-stented group and 83.2% for the non-stented group, showing no significant (p = 0.498) difference between the two groups. Preoperative ureteral stenting improved the success rate of sheath placement (93.8% vs. 85.3%, p = 0.023) during surgery. The access sheath size in participants in the pre-stented group showed a tendency to be larger than that in participants in the non-stented group. However, there were no differences in perioperative complications, operative times, additional treatment rates, and stone-free rates.

Conclusions

Although preoperative ureteral stenting did not affect operative outcomes, it increased the success rate of access sheath placement. Depending on the patient’s characteristics, preoperative ureteral stenting can be considered as an adjunctive option when access sheath insertion is considered during RIRS.

The utility of automated volume analysis of renal stones before and after shockwave lithotripsy treatment

This study aimed to evaluate the additional utility of an automated method of estimating volume for stones being treated with shockwave lithotripsy (SWL) using computed tomography (CT) images compared to manual measurement. Utility was assessed as the ability to accurately measure stone burden before and after SWL treatment, and whether stone volume is a better predictor of SWL outcome than stone diameter. 72 patients treated with SWL for a renal stone with available CT scans before and after treatment were included. Stone axes measurement and volume estimation using ellipsoid equations were compared to volume estimation using software using CT textural analysis (CTTA) of stone images. There was strong correlation (r > 0.8) between manual and CTTA estimated stone volume. CTTA measured stone volume showed the highest predictive value (r² = 0.217) for successful SWL outcome on binary logistic regression analysis. Three cases that were originally classified as ‘stone-free with clinically insignificant residual fragments’ based on manual axis measurements actually had a larger stone volume based on CTTA estimation than the smallest fragments remaining for cases with an outcome of ‘not stone-free’. This study suggests objective measurement of total stone volume could improve estimation of stone burden before and after treatment. Current definitions of stone-free status based on manual measurements of residual fragment sizes are not accurate and may underestimate remaining stone burden after treatment. Future studies reporting on the efficacy of different stone treatments should consider using objective stone volume measurements based on CT image analysis as an outcome measure of stone-free state.

The correlation between demographic factors and upper urinary tract stone composition in the Thai population

Objective

To identify the correlation between demographic factors and upper urinary tract stone composition in the Thai population.

Method

A retrospective observational study of first-time upper urinary tract stone former patients aged over 18 years who underwent stone surgery was performed in a tertiary referral university hospital from January 2013 to May 2018. Collected data included demographic information and stone composition information, which were analysed by the Fourier Transform-Infrared Spectroscopy (FTIR) method. The correlation between the demographic factors and major upper urinary tract stone composition was analysed using Fisher's exact test.

Results

A total of 480 patients were included in this study. The stones were 319 (66.5%) renal calculi and 161 (33.5%) ureteric calculi. There were 248 (51.7%) single composition stones and 232 (48.3%) mixed composition stones. The major stone compositions were 288 (60.0%) calcium oxalate (CaOx), 125 (26.0%) calcium phosphate (CaP), 40 (8.3%) uric acid (UA), 19 (4.0%) magnesium ammonium phosphate (MAP), five (1.0%) cystine, and three (0.6%) ammonium hydrogen urate (AHU). Gender was correlated with the major stone composition. In females, a correlation was found between the major stone composition and age, diabetes mellitus (DM), and glomerular filtration rate (GFR). The study showed no significant correlation between the major stone composition and dyslipidemia (DLP), hypertension (HT), gout, and body mass index (BMI) in both genders.

Conclusion

Gender, age, DM, and GFR were the factors affecting the stone composition.

The Pros and cons of balloon dilation in totally ultrasound-guided percutaneous Nephrolithotomy

Background

To evaluate the feasibility and safety of balloon dilation (BD) in totally ultrasound-guided percutaneous nephrolithotomy (PCNL).

Methods

The data of 95 patients underwent BD were collected in this retrospective study between August 2016 and December 2018. During the same period, telescopic metal dilation was used in 1161 patients. Ninety five patients were selected as the control group and matched at a 1:1 ratio to index balloon dilation (BD) cases in regards to Guy’s stone score, age, sex, BMI, degree of hydronephrosis and stone area. Peri-operative data were compared between the two groups.

Results

Total operative time was significantly shorter in the BD group (62.2 ± 22.4 min vs. 70.2 ± 25.8 min, p = 0.024). Tract establishment time was significantly shorter in the BD group (3.4 ± 1.8 min vs. 4.3 ± 2.3 min, p < 0.001). The success rate of tract dilation by first attempt was higher in the TMD group compared with that of BD group; however the difference was not statistically significant. There was no significant difference between groups with regards to complication and stone-free rates. The cost of PCNL in the BD group was significantly higher than that of the TMD group (US $4831.4 ± 1114.8 vs. US $4328.4 ± 975.7, p = 0.012). Subsequent analysis revealed that mild or no hydronephrosis were risk factor for failure of balloon dilation under ultrasound.

Conclusions

BD has acceptable complication and stone free rates compared with those in TMD; however, BD under ultrasound is not suggested for stone cases without hydronephrosis.

The clinical and cost effectiveness of surgical interventions for stones in the lower pole of the kidney: the percutaneous nephrolithotomy, flexible ureterorenoscopy and extracorporeal shockwave lithotripsy for lower pole kidney stones randomised controlled trial (PUrE RCT) protocol

INTRODUCTION

Renal stones are common, with a lifetime prevalence of 10% in adults. Global incidence is increasing due to increases in obesity and diabetes, with these patient populations being more likely to suffer renal stone disease. Flank pain from stones (renal colic) is the most common cause of emergency admission to UK urology departments. Stones most commonly develop in the lower pole of the kidney (in ~35% of cases) and here are least likely to pass without intervention. Currently there are three technologies available within the UK National Health Service to remove lower pole kidney stones: extracorporeal shockwave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL) and flexible ureterorenoscopy (FURS) with laser lithotripsy. Current evidence indicates there is uncertainty regarding the management of lower pole stones, and each treatment has advantages and disadvantages. The aim of this trial is to determine the clinical and cost effectiveness of FURS compared with ESWL or PCNL in the treatment of lower pole kidney stones.

METHODS

The PUrE (PCNL, FURS and ESWL for lower pole kidney stones) trial is a multi-centre, randomised controlled trial (RCT) evaluating FURS versus ESWL or PCNL for lower pole kidney stones. Patients aged ≥16 years with a stone(s) in the lower pole of either kidney confirmed by non-contrast computed tomography of the kidney, ureter and bladder (CTKUB) and requiring treatment for a stone ≤10 mm will be randomised to receive FURS or ESWL (RCT1), and those requiring treatment for a stone >10 mm to ≤25 mm will be randomised to receive FURS or PCNL (RCT2). Participants will undergo follow-up by questionnaires every week up to 12 weeks post-intervention and at 12 months post-randomisation. The primary clinical outcome is health status measured by the area under the curve calculated from multiple measurements of the EuroQol five dimensions five-level version (EQ-5D-5L) questionnaire up to 12 weeks post-intervention. The primary economic outcome is the incremental cost per quality-adjusted life year gained at 12 months post-randomisation.

DISCUSSION

The PUrE trial aims to provide robust evidence on health status, quality of life, clinical outcomes and resource use to directly inform choice and National Health Service provision of the three treatment options.

TRIAL REGISTRATION

ISRCTN: ISRCTN98970319. Registered on 11 November 2015.

Does the renal parenchymal thickness affect the efficacy of the retrograde intrarenal surgery? A prospective cohort study

Retrograde intrarenal surgery (RIRS) is one of the minimally invasive main treatment modalities in renal stone disease. There are many factors which affect stone-free rate (SFR). Our study was based on the hypothesis that higher renal parenchymal thickness (RPT) which may include higher average number of nephrons provides better diuresis. We investigated the efficacy of RPT on success of RIRS. This study is a single-centered prospective surgical cohort study. A total of 383 patients were analyzed. Regularly followed 304 patients with unilateral kidney stone at single pole or renal pelvis and who underwent single-session RIRS were included in the final analysis, and the patients' preoperative and postoperative 1st and 3rd months' data were evaluated. RPT was measured on the non-contrast computed tomography (CT) images. ROC analysis was performed to estimate the cutoff value of RPT for SFR. Univariate and multivariate logistic regression analyses were used to model the relationship between RPT and SFR after RIRS. ROC analysis revealed the best cutoff value of the RPT for predicting residual stone as 19 mm for both the 1st and 3rd month visits with Youden indexes of 0.397 and 0.406, respectively. To the best of our knowledge, this is the first study which evaluated the effect of RPT on the efficacy of RIRS. RPT measurement is a cost-effective method that can be easily performed on routinely applied non-contrast CT and may have predictive value for the surgical success in patients with nephrolithiasis.

Minimally invasive versus standard endoscopic combined intrarenal surgery for renal stones: a retrospective pilot study analysis

PURPOSE

The effect of combining miniaturization with endoscopic combined intrarenal surgery (ECIRS) is unclear. Thus, we compared the treatment outcomes between minimally invasive ECIRS (mini-ECIRS) using 16.5 Fr percutaneous access sheath and standard ECIRS using 24 Fr access sheath for renal stones MATERIALS AND METHODS: We retrospectively analyzed consecutive patients who underwent single session mini or standard-ECIRS in the modified Valdivia position for renal stones between April 2009 and May 2016. To adjust for patient characteristics, 77 pairs were matched using preoperative parameters including age, sex, history of febrile urinary tract infection (UTI), stone surface area, number of involved calyces, and staghorn calculi.

RESULTS

The stone free rate (SFR) was similar between mini and standard ECIRS according to non-contrast computed tomography (61.1% vs. 52.0%, p = 0.388). The rate of perioperative complications exceeding grade 2 based on the Clavien-Dindo classification was similar in both groups (19.5% vs. 26.0%, p = 0.442). Severe complications exceeding grade 3 were also similar in both groups (2.6% vs. 3.9%, p > 0.99). Two cases of septic shock were noted in each group. Although there was no difference regarding bleeding-related complications (2.6% vs. 6.5%, p = 0.442), pseudoaneurysm or blood transfusion was not observed in the mini-ECIRS group. Pain visual analog scale values in the perioperative period were lower in the mini-ECIRS group (1.34 ± 1.08 vs. 1.69 ± 1.23, p = 0.062).

CONCLUSIONS

This study demonstrated that, compared to standard ECIRS, mini-ECIRS maintained SFR without increasing perioperative complications, tended to reduce postoperative pain and had a potential to reduce bleeding-related complications. This report suggests the advantages of ECIRS miniaturization for renal stones.

Influence of anesthesia methods on surgical outcomes and renal function in retrograde intrarenal stone surgery: a prospective, randomized controlled study

BACKGROUND

We analyzed the influence of anesthesia methods on surgical outcomes and renal function in retrograde intrarenal surgery (RIRS) in a prospective, randomized controlled study.

METHODS

Seventy patients who underwent RIRS from September 2015 to February 2017 were randomly allocated to general anesthesia (GA) or spinal anesthesia (SA) groups. Renal function was assessed using estimated glomerular filtration rate, and separate renal function was evaluated using nuclear medicine tests. Maneuverability and accessibility were evaluated after every surgery. All procedures were performed by a single experienced surgeon (SY Cho).

RESULTS

Stone-free rate was higher in the GA (92.3%, 36 of 39) than the SA (71.0%, 22 of 31) (P = 0.019) group. Pain score was higher in the GA than in the SA group on the first postoperative morning (P = 0.025), but pain scores of the two groups were similar before discharge (P = 0.560). There were no differences in the changes of serum creatinine level (P = 0.792) and changes of estimated glomerular filtration rate (P = 0.807). Differences of separate renal function between operative and contralateral site increased significantly in patients under GA than under SA at postoperative 3 months (P = 0.014). Maneuverability and accessibility were better in SA with sedation than GA (P < 0.001).

CONCLUSIONS

RIRS under SA showed advantages in renal function change using renogram at postoperative 3 months and in lower pain score on the first postoperative morning. Performance of operator under SA was worse than that under GA and significantly improved with sedation. RIRS under SA showed advantages in lower pain score at postoperative first day.

TRIAL REGISTRATION

Clinicaltrials.gov ID is NCT03957109, and registration date is 17th May 2019. This study was retrospectively registered.

The evaluation of early predictive factors for urosepsis in patients with negative preoperative urine culture following mini-percutaneous nephrolithotomy

PURPOSE

To identify early predictive factors for urosepsis secondary to mini-percutaneous nephrolithotomy (MPCNL) in patients with negative preoperative urine culture (UC).

METHODS

A total of 786 patients with baseline negative UC who underwent MPCNL between January 2017 and June 2019 were retrospectively analyzed. Urosepsis was defined according to the Sepsis-3 definition. Subsequently, perioperative potential risk factors were compared between non-urosepsis and urosepsis groups.

RESULTS

Despite negative UC in all patients, the rate of positive stone culture (SC) was 16.0%; the rate of pelvic urine culture (PUC) was 7.5%; 23 cases (2.9%) developed urosepsis after MPCNL. Univariate analysis showed that urosepsis was associated with the female gender, BMI, stone burden, diabetes mellitus and preoperative urine test. Multivariate logistic regression analysis suggested that urine test with positive nitrite and white blood cells and leukocyte esterase (N+WBC+LE+) (OR 17.51, 95% CI 6.75-45.38, P < 0.001) and operative time > 120 min (OR 3.53, 95% CI 1.41-8.85, P = 0.007) were independent risk factors for urosepsis. Additionally, receiver operating characteristic curve analysis of N+WBC+LE+ showed that the area under the curve was 0.785 for predicting the occurrence of urosepsis. Further analysis showed that N+WBC+LE+ provided an efficient prediction of SC+/PUC+ (SC+ or PUC+) with 61.7% sensitivity and 97.3% specificity.

CONCLUSIONS

In spite of the baseline negative preoperative UC, 2.9% of patients developed urosepsis after MPCNL. N+WBC+LE + was determined to be an early and efficient prediction of intraoperative bacterial status and urosepsis following MPCNL. Nevertheless, further studies are needed to confirm the results.

Clinical Significance of Twinkling Artifact in the Diagnosis of Urinary Stones

The twinkling artifact is a color Doppler artifact, but it could be used in the confirmation of urinary stones. Conventionally, gray-scale criteria (echogenic foci with acoustic shadowing) is used in the diagnosis of urinary stones, but unfortunately, its reliability is very low. If the color Doppler twinkling artifact is applied in conjunction with other provocative measures, then its overall reliability exceeds 95%. To determine the clinical significance of twinkling artifact in the diagnosis of urinary stones, this cross-sectional observational study was conducted at Gilani Ultrasound Center, Lahore, Pakistan. For the determination of clinical significance, 1350 patients were recruited for this study. All the patients had renal stones of variable size and location. All the patients were evaluated with gray-scale sonographic criteria, and then color Doppler was applied to look for the twinkling artifact. The findings were confirmed with other imaging modalities (i.e., plain X-ray, computed tomography scan, etc., or during patient follow up). Sensitivity and specificity of the gray-scale ultrasound criteria in the detection of urinary stones was 96.1% and 57.9%, respectively, while the sensitivity and specificity of the color Doppler twinkling artifact in the detection of urinary stones was 100.0% and 97.4%, respectively. It was concluded that the application of twinkling artifact is useful in the confirmation of urinary stones, but specifically, it is of great diagnostic value in the small (less than 5 mm) renal stones and stones adjacent to a strong reflector (i.e., ureteric stones or stones in the prostatic urethra).

Are Nephrostomy and Ureteral Stent Necessary after Multi-Access Percutaneous Nephrolithotomy?

Introduction

Totally tubeless percutaneous nephrolithotomy (PCNL) is a well-established technique used in single -access procedure nevertheless these results challenge the multi-access PCNL as a contra-indication to application of this technique.

Aims

To compare complication rates and safety of use of this technique after multi-access PCNL.

Methods

A Total of 130 patients with renal stones were enrolled in this cohort study. Totally tubeless PCNL with single access (Group A, n = 70) and multi-access (Group B, n = 60) were done and bleedings were assessed by measuring hemoglobin (Hb) drop, blood transfusion rate and need for angioembolization besides leakage rates which were also recorded.

Results

In the 130 patients who underwent totally tubeless PCNL, no leakage from puncture site nor angioembolization cases were identified. There was no significant statistical differences between 2 groups regarding Hb drop (1.91 in single access versus 2.20 in multi-access), transfusion rate and length of hospital stay (p > 0.05). Stone-free rate was increased from 91% in single access to 97% in multi access by adding percutaneous access sites (from 91% in single access to 97% in multi-access).

Conclusions

Multi-access totally tubeless PCNL seems feasible and has comparable complication rates including Hb drop besides providing the advantage of higher stone-free rates using multi-access tracts.

Could surgical experience of adult endourologist overcome the learning curve of retrograde intrarenal surgery in children?

With the increasing of the prevalence of pediatric urolithiasis (1-5%), retrograde intrarenal surgery (RIRS) is emerging as preferred option for the management of stones in pediatric patients. Although the principles of RIRS developed in adults can be applied in children, also expert adult endourologists feel uncomfortable to approach young patients due to long learning curve that usually is expected to be required in this particular setting. The aim of the study was to compare peri- and postoperative outcomes of RIRS in pediatric and adult patients performed by a single surgeon expert in adult endourology (> 500 RIRS) with no experience in pediatric urology. Data on patient characteristics of 30 consecutive patients (15 adults and 15 children) undergoing RIRS at our institution were collected retrospectively from January 2016 to October 2018. Mean age for the pediatric group was 11.8 years (IQR 8-16) and for the adult group was 56 years (IQR 49-58). No significative differences between the two groups in terms of peri- and postoperative outcomes were found. The most common complication was hematuria in 2/30 patients (1 children vs 1 adults) and fever 2/30 (1 pediatric patient vs 1 adult) (p = 1.00) that required antibiotic treatment (Clavien Dindo 2). Median length of stay was 1 day (IQR 1-1 days) in both groups (p = 1.00). Stone-free rate was 86.7% in children and 80% in adults (p = 0.624). Our preliminary experience suggests that expert adult endourologist can manage successfully also pediatric cases with results comparable to adults and low complication rate.

Factors Predicting Operating Room Time in Ureteroscopy and Ureterorenoscopy

Backgrounds/Aims

Operation room (OR) time is of great value affecting surgical outcome, complications and the daily surgical program with financial implications.

Methods

We retrospectively evaluated 570 consecutive patients submitted to ureteroscopy or ureterorenoscopy for the treatment of ureteral or renal stones. Demographic parameters, patient's stones characteristics, type of ureteroscope, surgeon experience and surgical theater characteristics were analyzed. OR time was calculated from the initiation of anesthesia to patient extubation. Multivariate analysis was conducted using a linear regression test with multiple parameters to identify predictors of OR time.

Results

Eight factors were identified as significant. These include total stones volume, ureteroscope used, stone number, nurses experience, radio-opacity of the stone on kidney-ureter-bladder X-ray, main surgeon experience, operating room type, and having a nephrostomy tube prior to surgery.

Conclusions

The surgical team experience and familiarity with endourological procedure, and the surgical room characteristics has a crucial impact on OR time and effectiveness.

Urinothorax causing massive left side pleural effusion in a young lady; case report and literature review

Urinothorax is the presence of the urine in the pleural space. This condition is very rare and occurs due to unrelieved obstruction of urinary flow.

A 20-year-old female presented 7 days after cesarean section with tachypnea, and generalized abdominal pain. There was absent air entry over the left hemithorax. CT scan showed massive left pleural effusion and a stone obstructing the renal pelvis with hydronephrosis and peri-renal collection. The pleural fluid had high fluid creatinine level suggesting urine collection. Ureteroscopy done and double J catheter inserted.

The effusion became loculated, thoracotomy and pleural decortication done.

Sheathless and fluoroscopy-free retrograde intrarenal surgery: An attractive way of renal stone management in high-volume stone centers

Objective

To evaluate the efficacy and safety of sheathless and fluoroscopy-free flexible ureterorenoscopic laser lithotripsy (FURSL) for treating renal stones.

Methods

Between May 2015 and May 2017, 135 patients with renal stones treated with sheathless and fluoroscopy-free FURSL were prospectively evaluated. Our technique involved a semi-rigid ureteroscopic assessment of the ureter, and the guidewire was left in situ to railroad the flexible ureteroscope. A holmium laser was used to fragment and dust the stones; fragments were neither grasped nor collected.

Results

The study population consisted of 135 patients including 85 males (62.96%) and 50 females (37.04%) with a mean age of 40.65 years (range: 3–70 years) were evaluated. The mean stone size was 17.23 mm (range: 8–41 mm). Complete stone-free status was achieved in 122 (90.37%) patients and clinically insignificant residual fragments (CIRF) in two (1.48%), while residual stones were still present in 11 (8.15%) patients. Postoperative complications occurred in 23 (17.4%) cases and were mostly minor, including fever in 17 (12.6%), pyelonephritis in four (3.0%), subcapsular hematoma in one (0.7%) and steinstrasse in one (0.7%). These complications were Clavien I-II, GI in 17 (12.6%) patients, GII in five (3.7%), and Clavien IIIb in one (0.7%). No major complications were observed. Stone size ≥2 cm, operative time ≥30 min, and lasing time ≥20 min were significantly associated with a higher rate of complications and lower stone-free rates upon univariate analysis (p<0.05).

Conclusion

Sheathless and fluoroscopy-free FURSL are effective and safe for renal stone management, especially for stones under 2 cm in diameter. This process is a feasible option for avoiding sheath complications, which can protect surgeons from the negative effects of radiation.

EMS Lithoclast Trilogy™: an effective single-probe dual-energy lithotripter for mini and standard PCNL

PURPOSE

Several energy sources are available to clear stones during PCNL. Required improvements are faster stone clearance, optimized suction and ease of use while maintaining high patient safety standard. EMS LithoClast^® Trilogy, is the first device combining electromagnetic impactor with ultrasonic energy and suction, all-in-one probe. Animal studies and in vitro phantom stone studies have proven safety and efficacy of this device. We aim to study safety and clinical efficacy of Trilogy in our patients.

METHODS

31 patients with renal stones were included. Amplatz sheath sizes/Trilogy probe size was 22-28 Fr/10.2 Fr for standard PNL (n = 20) and 15 Fr./5.7 Fr for mini PNL access (n = 11). Analysis was done with respect to demography, stone characteristics, operation duration (total time and lithotripter activation time), post op Hb drop, clearance rate and adverse events. Stone area/volume was calculated based on CT using 3D doctor. Efficacy was determined by stone volume clearance rate (mm³/min).

RESULTS

Male:female ratio was 6:5 and 16:4 for mini (MPNL)/standard PNL (SPNL). Stone densities were 1229 ± 206 vs. 1168 ± 344 HU (MPNL vs. SPNL). Mean stone volumes were 3776.1 ± 2132 mm³ for MPNL and 7096 ± 6441 for SPNL. Mean stone volume clearance ratios were 370.5 ± 171 mm³/min and 590.7 ± 250mm³/min for MPNL and SPNL, respectively. Hb drop was 1.24 ± 0.64 g/dL (MPNL) and 1.23 ± 0.89gm/dL (SPNL). Total procedure time/lithotripter activation time was 53.4 ± 23.8/14.7 ± 12.4 min for MPNL and 65.2 ± 23.5/12.0 ± 8.9 for SPNL. Immediate post-operative/1 month stone clearance rates were 93%/96% with one clinically insignificant residual fragment (< 3 mm) and no necessity for auxiliary procedures. No device failure occured and three Clavien grade I and one grade II complications were observed.

CONCLUSION

Swiss LithoClast^® Trilogy provides fast stone clearance in standard/mini-PCNL procedures. Ease of use, high tissue safety and optimized suction that avoids fragment blockings are other key features.

Does preoperative hydronephrosis affect the stone-free rate of micro-percutaneous nephrolithotomy?

OBJECTIVES

Micropercutaneous nephrolithotomy (microperc) is a new minimal-invasive technique.We aimed to investigate whether preoperative hydronephrosis has an impact on the stone-free rate of microperc.

METHODS

In this study, 66 consecutive patients were included and divided into 2 groups:patients without preoperative hydronephrosis (group-1) and patients with preoperative hydronephrosis (group-2).Both groups were compared for age, gender, body mass index (BMI), stone burden, stone location, fluoroscopy and operative time, blood loss, stone-free rate and perioperative and postoperative complication rates. Parameters were analyzed using univariate and multivariate analyses for the stone-free rate.

RESULTS

The mean age, gender, BMI, stone location, and blood loss were similar in both groups (p > 0.05). Stone burden in group-2 was greater than group-1 (p=0.011). In addition, mean fluoroscopy time in group-1 was found to be significantly lower (p < 0.05). However, operative time was comparable among the groups (p=0.169). Lastly, group-2 had a higher rate of perioperative and postoperative complication rates and lower success rate (p=0.023, p=0.027 and p=0.001, respectively). The success was significantly affected by hydronephrosis, stone burden and location (p < 0.05). Logistic regression analysis revealed that unsuccessful outcome was significantly associated only with the presence of hydronephrosis (OR 0.225,p=0.033).

CONCLUSION

This study seems to suggest that presence of hydronephrosis is a major factor on the stone free rate of microperc procedures.