Predictors of clinical outcomes of flexible ureterorenoscopy with holmium laser for renal stone greater than 2 cm

Small tools, big impact and redefining endourology: the paradigm shift of ureteroscopy for large stones and percutaneous nephrolithotomy for small stones - a literature review

PURPOSE OF REVIEW

We aim to review the evolving paradigm in endourology, where technology has led us to manage small stones with ureteroscopy (URS) and large stones with miniaturized percutaneous nephrolithotomy (mPCNL) techniques. We analyse recent literature, their findings, emerging trends and newer technologies that are helping redefine modern day endourology in pushing these boundaries.

RECENT FINDINGS

A significant trend is the use of smaller devices to treat larger stones via ureteroscopy, and to treat smaller stones via percutaneous nephrolithotomy (PCNL). Improved laser technologies, smaller single use ureteroscopes and nephroscopes, suction access sheaths, all play a key role in this.The use of suction sheaths and vacuum assisted devices allows to control intrarenal pressure and help in reducing infectious and other complications whilst improving the stone-free rate (SFR). The treatment choice often depends on surgical expertise and available resources, guided by anatomical factors, stone composition and patient-specific considerations.

SUMMARY

The management of kidney stone disease has undergone a paradigm shift. While ureteroscopy is being done for larger renal stones, miniaturised PCNL is being done for small stones. This has been driven by a surge in technology, but a tailored and patient-centred approach is needed, and must be helped by guidelines and a multidisciplinary approach.

Complications of Single-Use Flexible Ureteroscopy vs. Reusable Flexible Ureteroscopy: A Narrative Review

Urolithiasis, or kidney stones, is a painful condition that is becoming increasingly common worldwide. For many, the solution lies in a minimally invasive procedure called flexible ureteroscopy (fURS). This technique involves inserting a tiny, flexible scope into the urinary tract to break up and remove stones. Reusable fURS scopes have traditionally been the norm. However, concerns about infection control and instrument durability have led to the development of single-use scopes. While both methods offer effective treatment, the question remains: which one is safer and more efficient? To answer this, we conducted a comprehensive review of the available research. We analyzed 37 studies that compared single-use and reusable fURS complication rates. While both methods carry risks, such as bleeding, infection, and ureteral injury, the overall complication rates were found to be similar. As technology continues to advance, fURS is becoming even safer and more effective. However, there is still a need for standardized reporting and further research to better understand the potential risks and benefits of both single-use and reusable scopes. Ultimately, the choice between the two will depend on various factors, including patient factors, surgeon preference, and healthcare resource availability.

Optimizing outcome reporting after robotic flexible ureteroscopy for management of renal calculi: Introducing the concept of tetrafecta

Robotic flexible ureteroscopy (RFURS) has shown encouraging results in terms of stone free rate (SFR) and better ergonomics compared to conventional FURS. However, few studies have reported its outcomes. The goal of this study was to report our initial results of RFURS, furthermore we proposed a novel metrics for composite outcome reporting named tetrafecta. A retrospective analysis of electronic records of 100 patients treated with RFURS for renal stones between 2019 till 2023 was performed. Tetrafecta criteria included, complete stone removal after a single treatment session, without auxiliary procedures, absence of high-grade complications (GIII-V) and same-day hospital discharge. Mean patient age and stone size were 40.7 ± 9.2 and 11.7 ± 5.8 mm, respectively. Median stone volume was 916 (421-12,235) mm3. Twenty-eight patients had multiple renal stones. Staghorn stones were seen in 12 patients. Preoperative DJ stent was fixed in 58 patients. Median operative time and stone treatment time were 116 min (97-148) and 37 (22-69) min. The median stone treatment efficiency (STE) was 21.6 (8.9-41.6). A strong positive correlation between stone volume and STE (R = 0.8, p < 0.0001). Overall, 73 patients were stone free after the initial treatment session while tetrafecta was achieved in 70 patients. Univariate analysis showed that the stone size (p = 0.008), acute infundibulopelvic angle (p = 0.023) and preoperative stenting (p = 0.017) had significant influence on achieving tetrafecta. Multivariate analysis identified preoperative stenting (OR 0.3, 95% CI 0.1-0.8, p = 0.019) as the only independent predictor of tetrafecta achievement. A comprehensive reporting methodology for reporting outcomes of RFURS is indicated for patient counseling and comparing different techniques. Tetrafecta was achieved in 70% of cases. Presence of significant residual stones ≥ 3mm was the leading cause of missing tetrafecta. Absence of preoperative stent was the only predictor of missing tetrafecta.

The outcomes of flexible ureteroscopy for renal calculi of 2 cm or more with and without the use of ureteral access sheath: A retrospective study

INTRODUCTION

The rate of success of retrograde intrarenal surgery (RIRS) for treating urinary tract stones is high, and the procedure is growing in popularity. The routine use of ureteral access sheath (UAS) remains somewhat controversial. The aim of this study was to assess the efficacy and safety of employing UAS during flexible ureteroscopy for treating renal stones ≥ 2 cm.

METHODS

This retrospective study was accomplished from January 2021 to February 2023. From 495 consecutives flexible ureteroscopies, 112 patients had renal stones ≥ 2 cm (60 patients with the use of UAS and 52 patients without). The stone-free status was verified after 8 weeks of operation.

RESULTS

The average diameter of the renal stones in non-UAS or UAS treated groups was 22.5 mm and 22.6, respectively. None of the groups differed significantly in terms of stone side, stone size, stone position, or Hounsfield unite but there was significant difference (p < 0.001) among two groups as regard pre-operative stenting (cases with UAS had 23.3% pre-operative stenting).

CONCLUSIONS

It is not always necessary to use UAS in conjunction with flexible ureteroscopy and laser lithotripsy to treat renal calculi bigger than or equal two cm. Without the assistance of UAS, the surgery may be carried out successfully and safely.

External validation of the current scoring systems and derivation of a novel scoring system to predict stone free rates after retrograde intrarenal surgery in patients with cumulative stone diameter of 2-4 cm

OBJECTIVE

Our primary aim is to perform the external validation of the current scoring systems in predicting stone-free status (SFS) after retrograde intrarenal surgery (RIRS) for renal stones 2-4 cm and develop a novel scoring system by re-examining possible predictive factors related to SFS.

METHODS

Patients who underwent RIRS due to renal stones with a cumulative stone diameter of 2-4 cm between January 2017 and March 2021 were retrospectively screened. Residual stones ≤2 mm were defined as clinically insignificant, and these cases were considered to have SFS. Possible predictive factors related to SFS were examined using the multivariate logistic regression analysis. A nomogram and a scoring system were developed using independent predictive variables. The prediction ability of the previous and the new scoring system were evaluated with the ROC analysis.

RESULTS

The existing scoring systems were found to be insufficient in predicting SFS (AUC < 0.660 for all). The independent predictors of SFS were identified as stone surface area (OR: 0.991, p < 0.001), stone density (OR: 0.998, p < 0.001), number of stones (OR: 0.365, p = 0.033), and stone localization (p = 0.037). Using these predictive markers, a new scoring system with a score ranging between 4 and 15 was developed. The AUC value for this scoring system was 0.802 (0.734-0.870).

CONCLUSION

The RUSS, S-ReSC and R.I.R.S. scoring systems and Ito's nomogram failed to predict SFS in stones >2 cm. The SFS predictive ability of our new scoring system was higher in >2 cm stones compared to the other scoring systems.

Impact of stone volume on treatment outcomes of percutaneous nephrolithotripsy

PURPOSE

We aimed to evaluate the impact of stone volume on the surgical outcomes of patients who underwent percutaneous nephrolithotripsy, which is the preferred treatment for renal and upper ureteral stones.

MATERIALS AND METHODS

This retrospective study included 37 patients who underwent percutaneous lithotripsy between 2013 and 2019. Preoperative and postoperative stone volumes were quantified using computed tomography scan data.

RESULTS

The mean preoperative and postoperative stone volumes were 10.7 cm³ (1.1-50.2 cm³ ) and 2.1 cm³ (0-18.2 cm³ ), respectively. The correlation coefficient between the stone volume and maximum stone length was 0.62 (P < .01). A residual stone volume of >5 mm was observed in 17 cases (45.9%). Thirteen cases underwent secondary treatment (35.1%) who had a preoperative stone volume of >15 cm³ or a postoperative stone volume of <2 cm³ . The areas under the curve for the stone volume for treatment success and the requirement for secondary treatment were 0.701 and 0.739, respectively, and were higher than those of stone length (0.638 and 0.558) and shape (0.644 and 0.641).

CONCLUSIONS

Measurement of stone volume using three-dimensional imaging is simple and greatly impacted the course of stone treatment. Information on stone volume may predict an increased likelihood of secondary treatment in patients with a preoperative stone volume of >15 cm³ .

Is Retrograde Intrarenal Surgery as Safe for Children as It Is for Adults?

INTRODUCTION

The primary aim of this study is to compare the efficacy and safety of retrograde intrarenal surgery (RIRS) among the children and adults with similar stone burdens and locations. Also, the secondary aim of this study is to identify the factors affecting the stone-free rates (SFRs) of RIRS.

METHODS

We retrospectively compared perioperative results, SFRs, and complication rates (CRs) between pediatric (group 1, n: 55) and adult (group 2, n: 220) age groups diagnosed with kidney stones and treated by flexible ureterorenoscopy using the same instruments. Furthermore, multivariate analysis was performed to determine the factors affecting the SFR.

RESULTS

A total of 275 patients (pediatric group: 55; adult group: 220) were included in this study. The mean age of pediatric and adult groups was 7.2 ± 5.3 and 43.9 ± 15.1, respectively. The mean stone size was 13.9 ± 6.6 mm in the pediatric group compared to 14.8 ± 6.7 mm in the adult group (p = 0.35). Stone localizations and number were similar. JJ stenting for passive dilatation and use of UAS were higher in the pediatric group (p = 0.002; p = 0.017). However, postoperative double pigtail stenting rate was higher in the adult group (p < 0.001). Total CR was 13.8% and mostly Clavien I-II, and no difference was observed between the 2 groups (p = 0.541). The SFRs between the groups were similar (pediatric group: 81.8%; adult group: 78.2%; p = 0.554). On multivariate analysis, stone size (p < 0.001) and lower calyx stone (p < 0.001) were the negative predictive factors for SFR.

CONCLUSION

There are small technical differences between pediatric patients and adult patients in our study, but RIRS in children is as safe and efficient as it is in adults.

Comparison of single-use and reusable flexible ureteroscope for renal stone management: a pooled analysis of 772 patients

Flexible ureteroscopy is a common therapy for patients with renal calculi. In recent years, the prevalence of single-use flexible ureteroscope (FURS) use has been on the rise. Thus, several trials have been conducted to compare the efficacy between single-use and reusable FURS. The aim of this meta-analysis was to systematically assess the effectiveness and safety of single-use vs. reusable FURS in treating renal stones. PubMed, Web of Science, Cochrane Library and EMBASE were researched to identify relevant studies up to September 2019. Article selection was performed through the search strategy based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. The Newcastle-Ottawa Scale was applied to assess the methodological quality of non-randomized controlled trials, and the methodological quality of randomized controlled trials was evaluated using the Jadad scale. A total of five studies with 772 patients were included in the meta-analysis, including two randomized controlled trials, two single-centre prospective studies, and one prospective case-control trial. The pooled results showed that single-use FURS was associated with a higher stone-free rate (SFR) (OR: 1.50; 95% CI, 1.06–2.12; P=0.02) than reusable FURS. A significant difference was noted in operative time, and single-use FURS was associated with a longer operative duration (MD: 7.39 min; 95% CI, 1.75–13.03; P=0.01). No significant difference was noted in perioperative complications (OR: 0.97; 95% CI, 0.56–1.70; P=0.92). Subgroup analysis showed no significant difference in urinary tract infection (OR: 0.80; 95% CI, 0.44–1.46; P=0.46), stent migration (OR: 0.56; 95% CI, 0.19–1.65; P=0.30) or acute kidney injury (OR: 0.76; 95% CI, 0.16–3.57; P=0.73). Single-use FURS is an effective and safe alternative to reusable FURS for the management of renal stones.

Flexible ureteroscopy and laser lithotripsy for renal stones 2 cm or greater: A single institutional experience

With improvements in endoscopy and laser technology, flexible ureteroscopy (FURS) has been a viable treatment option for large renal stones. Here, we share our experience of the FURS treatment for renal stones 2 cm or greater.We evaluated 251 consecutive patients who underwent FURS and holmium laser lithotripsy for renal stones 2 cm or greater between January 2015 and April 2019. Stone size was defined as the longest axis on non-contrast computed tomography. Data were retrospectively collected from electronic medical records. Patient demographics, stone clearance rates and perioperative complications were evaluated.There were 165 male patients and 86 female patients with an average age of 46.9 years (range 22-80 years). Mean stone size was 2.7 cm and the average number of procedures was 1.4 (range 1-5). The stone-free rate at the end of the first, second and third procedure was 61.9%, 82.9%, and 89.5%, respectively. The final stone-free rate decreased as stone size grows, and it was only 58.3% for kidney stones larger than 4 cm after an average of 2.3 procedures. The lowest clearance rates were observed in lower calyx calculi (87.2%) and multiple calyx calculi (83.5%). The overall complication rate was 15.1%, and the most common complication was postoperative fever (9.6%). One patient required blood transfusion, owing to postoperative coagulation disorders induced by urosepsis.Single or staged FURS is a practical treatment option for the renal stones sized 2 to 4 cm with acceptable efficacy and safety. Stone clearance rate of FURS treatment is mainly affected by stone size and location.

Early experience of Retrograde Intrarenal Surgery for Renal stone: A Descriptive Cross-sectional Study

Introduction:

Retrograde intrarenal surgery with improving skill and knowledge may be considered one of the first-line treatment options for removal of renal stones. The study is done to find the outcome of retrograde intrarenal surgery (RIRS) in patients with renal stone.

Method:

This descriptive cross sectional study was carried out on patients undergoing retrograde intrarenal surgery for renal stone at a tertiary care hospital December 2019 to March 2020. Ethical approval was taken from the institutional review committee (Ref. no.200120202). The Convenient sampling method was applied. Data was collected and analyzed in Statistical Package for the Social Sciences version 20.0. Point estimate at 95% confidence interval was calculated along with frequency and proportion for binary data.

Results:

Out of the 28 patients, the retrograde intrarenal surgery was successful in 27 (96.4%) cases. There were 16 (57.15%) females and 12 (42.86%) male patients with the mean age of 37.86±11.47 years. Most of the stones were in renal pelvis 18 (64.28%) followed by lower calyx 8(28.57%). The mean diameter of the stone was 11.47±3.33mm whereas most of the stones were on the right side 16 (57.15%). The mean hardness was 1155.21±265.34 Hounsfield units. Perioperative complications like failed access sheath placement in 2 (7.14%) cases, hematuria in 6 (21.43%) cases, fever in 6 (21.43%) cases, and septicemia in 4 (14.28%) cases.

Conclusions:

We found that the success rate of retrograde intrarenal surgery for the renal stone was acceptable and similar to other published studies . Retrograde intrarenal surgery is feasible for the treatment of kidney stones with acceptable complications and success rates.

Analysis of performance factors in 240 consecutive cases of robot-assisted flexible ureteroscopic stone treatment

Flexible ureteroscopy is the keystone of modern kidney stone treatment. Although a simple surgical technique achieves good clinical results and a low complication rate, there are high demands on the surgeon's dexterity and ergonomic restrictions. Robotic-assisted flexible ureteroscopy (rfURS) could overcome these limitations. After 4 years of use of rfURS at a tertiary stone center, performance factors were analyzed to define the role of rfURS in kidney stone management. A rfURS system was installed in August 2014 at the SLK Kliniken (Heilbronn, Germany). Treatment data of N = 240 consecutive patients undergoing rfURS were prospectively collected and analyzed. The patient cohort represents typical stone formers. N = 240 renal units containing 443 stones with an average stone load of 1798 mm³ were treated. Surgical parameters as well as the peri- and postoperative complications were recorded, analyzed and compared to the current data in the literature. OR time 91 min, stone treatment time 55 min, stone treatment efficacy 33 mm³/min; perioperative complications 5.4%; robot times: preparation 5 min, docking 5 min, console time to stone contact 6 min, console time 75 min; postoperative complications 6.7%; postoperative length of stay 1.5 days; stone-free rate (residuals < 2 mm) 90% and re-treatment rate 8.75%. This consecutive series represents real-life data about the utilization of rfURS. The detailed analysis of performance factors revealed the successful utilization of the first generation of robotic systems in endourologic stone surgery, and indicates that the robot performs comparably to conventional flexible URS. Optimal ergonomics maintain the surgeon's endurance in long-lasting surgeries.

Comparison among the available stone treatment techniques from the first European Association of Urology Section of Urolithiasis (EULIS) Survey: Do we have a Queen?

PURPOSE

The miniaturization of instruments has had an impact on stone management. The aims of this study were to highlight surgeon preferences among Retrograde Intra Renal Surgery (RIRS), Regular, Mini-, UltraMini- and Micro- Percutaneous Nephrolithotomy (PCNL) for urolithiasis and to compare the effectiveness and safety of these techniques in a real-life setting.

METHODS

A 12-item survey regarding endourological techniques was conducted through Survey Monkey among attendees of the 2013 European Association of Urology Section of Urolithiasis meeting. We asked responders to share data from the last 5 cases they performed for each technique. Procedures were stratified according to stone size and the centres' surgical volume. Techniques were compared in terms of effectiveness and safety. Analyses were performed on the overall group and a subgroup of 1-2 cm stones.

RESULTS

We collected data from a total of 420 procedures by 30, out of 78, urologists who received the survey (response rate 38%): 140 RIRS, 141 Regular-PCNL (>20 Ch), 67 Mini-PCNL (14-20 Ch), 28 UltraMini-PCNL (11-13 Ch) and 44 Micro-PCNL (4,8-8 Ch). Techniques choice was influenced by stone size and the centre's surgical volume. Effectiveness and safety outcomes were influenced by stone size, independently of the technique. The stone-free rate was significantly lower in Micro-PCNL compared to Regular-PCNL. This was not confirmed for 1-2 cm stones. All techniques presented a lower complication rate than Regular-PCNL, with Mini-PCNL being the most protective technique compared to Regular-PCNL.

CONCLUSIONS

Stone size seems to drive treatment choice. Miniaturized PCNL techniques are widely employed for 1-2 cm stones, in particular in higher surgical volume centres. Mini-PCNL and RIRS are growing in popularity for stones > 2 cm. Mini-PCNL seems to be a good compromise, being the most effective and safe procedure among PCNL techniques. RIRS is characterized by satisfactory stone-free and low complication rates.

To Dust or Not To Dust: a Systematic Review of Ureteroscopic Laser Lithotripsy Techniques

PURPOSE OF REVIEW

This review discusses factors affecting outcomes during ureteroscopy (URS) with laser lithotripsy (LL), explores specific clinical challenges to the efficacy of URS LL, and reviews the available literature comparing the dusting and basketing approaches to URS LL.

RECENT FINDINGS

Data show high stone-free rates with URS LL in all locations of the urinary tract and with all stone types and sizes. Recent data comparing LL with dusting versus basketing suggest higher rates of residual fragments with dusting but less utilization of ureteral access sheaths and potentially shorter operative times. Differences in postoperative complications, re-intervention rates, and other outcome parameters are not yet clear. Interpretation of published data is problematic due to variability in laser settings, follow-up intervals, and definitions for what constitutes stone-free status. URS has overtaken shock wave lithotripsy in the last decade as the most commonly utilized surgical approach for treating urolithiasis. Two primary strategies have emerged as the most common techniques for performing LL: dusting and basketing. There is a relative paucity of data examining the difference in these techniques as it pertains to peri-operative outcomes and overall success. We attempt to synthesize this data into evidence-based and experience-based recommendations.

Imaging for Urinary Stones: Update in 2015

CONTEXT

Imaging is essential for the diagnosis and the clinical decision-making process of patients with urinary stones.

OBJECTIVE

To assess the benefits and limitations of various imaging techniques by specifically focusing on different phases of stone patients' management.

EVIDENCE ACQUISITION

PubMed and Web of Science databases were used to identify studies published in the last 10 yr on this argument. Search terms included 'urolithiasis', nephrolithiasis', or 'urinary stones' in combination (AND) with the terms 'imaging', 'computer tomography', 'ultrasonography', 'intravenous pyelogram', or 'radiation exposure'. Study selection was based on an independent peer-review process of all the authors after the structured data search.

EVIDENCE SYNTHESIS

Noncontrast-enhanced computer tomography (CT) provides the highest value of diagnostic accuracy for urinary stones. Stone composition can be specifically assessed through the use of dual-energy CT. When information about the anatomy of the renal collecting system is required or alternative pathologies are suspected, CT with contrast injection is recommended. Low-dose protocols allowed a drastic reduction of the effective dose administered to the patient, thus limiting the biological risk due to ionising radiations. Other strategies to contain the radiation exposure include the dual-split bolus dual energy CT and the adaptive statistical image reconstruction. Abdomen ultrasound may be a valid alternative as an initial approach since it does not change the outcome of patients compared with CT, and should be the imaging of choice in children and pregnant women.

CONCLUSIONS

Noncontrast-enhanced CT is the most accurate imaging technique to identify urinary stones. Abdomen ultrasound seems to be a valid alternative in the initial evaluation of urinary colic. New low-dose protocols and strategies have been developed to contain radiation exposure, which is a major issue especially in specific circumstances.

PATIENT SUMMARY

Noncontrast-enhanced computer tomography has been increasingly used for the diagnosis and management of urinary stones. Low-dose protocols as well as alternative imaging should be considered by clinicians in specific circumstances to minimise radiation exposure.

Intrarenal pressure and irrigation flow with commonly used ureteric access sheaths and instruments

INTRODUCTION

Flexible ureterorenoscopy is becoming a first-line treatment for many intrarenal stones. Ureteric access sheaths are commonly used to aid access, stone removal and reduce intrarenal pressure. We evaluated the effects of two commonly used access sheaths on irrigation flow and intrarenal pressure during flexible ureterorenoscopy. We measured the effect of scope instrumentation on flow and pressure.

MATERIAL AND METHODS

We utilized a 10/12F and 12/14F, 35 cm Re-Trace™ access sheath with a FlexX2 scope in a cadaveric porcine kidney. We evaluated the effect of four Nitinol baskets (1.3F, 1.5F, 1.9F, 2.2F), three different 200 µm laser fibres and a hand-held pump. Measurements of irrigation flow and intrarenal pressure were recorded and compared between the different sized access sheaths.

RESULTS

Flow rates varied widely between access sheaths. Without instrumentation, mean flow was 17 mls/min (10/12F access sheath), versus 33 mls/min (12/14F sheath) (p <0.0001). Increasing basket size produced a gradual reduction in flow and pressure in both access sheaths. Reassuringly, pressures were low overall (<40 cm H2O). Pressures were significantly reduced when using the larger 12/14F sheath, with and without all instrumentations (p <0.0001). Hand-held pump devices have a marked effect on flow and pressure in both sheaths; with pressures rising up to 121 cm H2O with a 10/12F sheath, versus 29 cm H2O (12/14F) (p <0.0001).

CONCLUSIONS

A 12/14F access sheath offered significantly improved irrigation whilst maintaining significantly lower intrarenal pressure, when compared to a 10/12F access sheath in a cadaveric porcine model. Scope instrumentation affects irrigation flow and pressure in both sized sheaths. Furthermore, there should be caution with hand-held pump devices, especially with smaller sized sheaths, as intrarenal pressure can be very high.

Retrograde intrarenal surgery for kidney stones larger than 2.5 cm

PURPOSE OF REVIEW

The management of large intrarenal stones (>2 cm) is typically percutaneous nephrolithotomy. Although the stone-free rate (SFR) of such a procedure is high (up to 95%), the complications related mainly to the renal access are sometimes a concern. Because of the evolution in technology, it is nowadays possible to treat intrarenal stones with retrograde intrarenal surgery. It remains unclear weather or not retrograde intrarenal surgery (RIRS) may be effective also for the treatment of larger stones (>2 cm). The purpose of this review is to provide recent data on the ureteroscopic management of kidney stones larger than 2.5 cm.

RECENT FINDINGS

A systematic review of the literature for studies identified between January 2000 and September 2013 was performed. Only English language articles reporting on more than 10 cases treated with RIRS for intrarenal stones larger than 2.5 cm were considered for this review.Particular emphasis was given to studies published within the last 12 months. Of the 324 studies identified, only 10 were considered suitable for this review. There were a total of 441 patients with a mean stone size of 2.9 cm. The SFR with an average of 1.6 procedures was 89.3%. The overall complication rate was 8% with major complication rate of 1.9%.

SUMMARY

Although not supported by high evidence because of the absence of prospective randomized studies, it appears that in selected patients with large intrarenal stones, RIRS and laser lithotripsy may offer an acceptable efficacy with low morbidity.

Retrograde intrarenal surgery versus percutaneous nephrolithotomy for treatment of renal stones >2 cm: a meta-analysis

OBJECTIVE

To systematically review the efficacy and safety of retrograde intrarenal surgery (RIRS) versus percutaneous nephrolithotomy (PCNL) for the treatment of renal calculi >2 cm.

METHODS

We searched PubMed, Cochrane Library, Embase and the Chinese Biomedical Literature Database about RIRS and PCNL for the treatment of renal stones. The retrieval time ended in December 2013. All clinical trials were retrieved and their included references investigated. Two reviewers independently assessed the quality of all included studies, and the eligible studies were included and analyzed using the RevMan 5.2 software.

RESULTS

Two randomized controlled trials and six clinical controlled trials were included, involving a total of 590 patients. Our meta-analysis showed that there were not significant differences in stone-free rate (relative risk [RR] = 0.95, 95% confidence interval (CI) 0.88-1.02, p = 0.11) and fever (RR = 0.95, 95% CI 0.54-1.67, p = 0.85) between RIRS and PCNL. We found that hospital stay (weighted mean difference [WMD] = -2.10, 95% CI -3.08 to -1.11, p < 0.10) and bleeding (RR = 0.20, 95% CI 0.06-0.68, p = 0.01) were lower and operation time was longer (WMD = 19.11, 95% CI 7.83-30.39, p < 0.10) for RIRS.

CONCLUSION

RIRS is a safe and effective procedure. It can successfully treat patients with stones >2 cm with a high stone-free rate and significantly reduce hospital stay without increasing complications. RIRS can be used as an alternative treatment to PCNL in selected cases with larger renal stones. However, further randomized trials are needed to confirm these findings.

Results of retrograde intrarenal surgery in the treatment of renal stones greater than 2 cm

OBJECTIVE

To analyze the results of retrograde intrarenal surgery (RIRS) in patients with ≥2 cm stones treated in our center.

MATERIAL AND METHODS

A retrospective review of 106 patients with renal calculi underwent RIRS ≥2 cm (period January 2009-December 2011). The procedures were performed under general anesthesia as a source of fragmentation using the holmium laser (30 W Litho Quantasystem) and flexible ureteroscopes (X2 Flex Storz, Olympus P5) through ureteral access sheaths. It discusses demographic variables (age, medical history, antiplatelet or anticoagulant treatment, treatment of urolithiasis, BMI, ASA), treated stones variables (size, number, Hounsfield units, biochemical composition) and intra-and postoperative variables (operative time, number of pulses, hospital stay, complications) with the completion of a descriptive analysis of the same. To define our results we consider success to the complete absence of fragments or residual <5 mm posterior imaging tests.

RESULTS

The mean stone size was 2.46 cm treated, being the only stone in 87.7% of cases. The most frequent location was the renal pelvis stones (44%) followed by the lower calyx (39%). The postoperative complication rate was 6.7%, with all of little relevance. The success rate with a single procedure was 79.4% to 94.1% with retreatment.

CONCLUSION

RIRS is a valid alternative for the treatment of kidney stones ≥2 cm for its high success rate and few complications if performed in specialized centers.

[Ureteroscopy: is it the best?]

Over the last 40 years the treatment of urolithiasis passed from open surgical therapies to minimally invasive approaches. From the introduction of the first ureteroscopes in '80s many technological improvements allowed to reduce endourological instruments' size, ensuring in the meanwhile an increasingly high success rate in the resolution of the urolithiasis. The purpose of the study is to review the current role of the ureteroscopy(URS) in the treatment of urinary stones. A non-systematic review was performed considering the most recent Guidelines and results from Literature. The results confirm that, considering ureteral calculi, the stone-free rate (SFR) for URS is significantly higher than for ESWL in the treatment of distal ureteral stones <10 mm and >10 mm. Endoscopy has a first-line role also in the treatment of proximal ureteral stones >10 mm, together with ESWL. Retreatment rate and ancillary procedures are also lower in patients treated with URS, despite it is more invasive if compared with ESWL. Recent data are available in Literature about the treatment of nephrolithiasis with Retrograde Intra-Renal Surgery (RIRS). RIRS is the first-line treatment, together with ESWL, for stones <20 mm, and second choice for stones >20 mm. However, for large renal stones the role of RIRS is still being discussed. In conclusion, the majority of urinary stones can be treated by rigid or flexible URS. Further studies are required to clarify the role of endoscopy in the treatment of large stones, especially if compared to percutaneous approaches.

Categorizing intraoperative complications of retrograde intrarenal surgery

PURPOSE

To review our intraoperative complications of retrograde intrarenal surgery (RIRS) for kidney calculi and stratify these complications according to the modified Satava classification system (SCS).

PATIENTS AND METHODS

230 patients (119 males, 111 females) who underwent RIRS because of kidney calculi were analyzed. We documented and stratified the intraoperative complications according to the modified SCS. There are four grades for this classification: grade 1 complications include events without consequences for patients; grade 2a complications include events that could be treated with endoscopic surgery intraoperatively; grade 2b complications include events which were treated with endoscopic treatment in another session, and grade 3 describes the events requiring laparoscopic or open surgery.

RESULTS

Mean age was 39.1 years (range 1-78). The stone-free rate after one session was 81%. Intraoperative complications were recorded in 30.4% of the patients. According to the modified SCS, grade 1 complications were documented in 15.9%, grade 2a complications were documented in 5.6%, and grade 2b complications were documented in 8.9% of the patients. Grade 3 complications were not detected in any of the patients.

CONCLUSION

In our opinion, the modified SCS can facilitate patients to understand the safety of this surgery and can make it easier to compare the results of different institutes and surgeons.

Measuring stone volume - three-dimensional software reconstruction or an ellipsoid algebra formula?

OBJECTIVES

To determine the optimal method for assessing stone volume, and thus stone burden, by comparing the accuracy of scalene, oblate, and prolate ellipsoid volume equations with three-dimensional (3D)-reconstructed stone volume. Kidney stone volume may be helpful in predicting treatment outcome for renal stones. While the precise measurement of stone volume by 3D reconstruction can be accomplished using modern computer tomography (CT) scanning software, this technique is not available in all hospitals or with routine acute colic scanning protocols. Therefore, maximum diameters as measured by either X-ray or CT are used in the calculation of stone volume based on a scalene ellipsoid formula, as recommended by the European Association of Urology.

METHODS

In all, 100 stones with both X-ray and CT (1-2-mm slices) were reviewed. Complete and partial staghorn stones were excluded. Stone volume was calculated using software designed to measure tissue density of a certain range within a specified region of interest. Correlation coefficients among all measured outcomes were compared. Stone volumes were analysed to determine the average 'shape' of the stones.

RESULTS

The maximum stone diameter on X-ray was 3-25 mm and on CT was 3-36 mm, with a reasonable correlation (r = 0.77). Smaller stones (<9 mm) trended towards prolate ellipsoids ('rugby-ball' shaped), stones of 9-15 mm towards oblate ellipsoids (disc shaped), and stones >15 mm towards scalene ellipsoids. There was no difference in stone shape by location within the kidney.

CONCLUSIONS

As the average shape of renal stones changes with diameter, no single equation for estimating stone volume can be recommended. As the maximum diameter increases, calculated stone volume becomes less accurate, suggesting that larger stones have more asymmetric shapes. We recommend that research looking at stone clearance rates should use 3D-reconstructed stone volumes when available, followed by prolate, oblate, or scalene ellipsoid formulas depending on the maximum stone diameter.

Flexible ureteroscopy and laser lithotripsy for stones >2 cm: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

Urinary stones >2 cm are traditionally managed with percutaneous nephrolithotomy (PCNL). Recently, flexible ureteroscopy and laser lithotripsy) (FURSL) has been used to manage them with comparable results. In a comparative study of renal stones between 2 and 3 cm, FURSL was reported to need less second-stage procedures and be just as effective as PCNL. Our purpose was to review the literature for renal stones >2 cm managed by ureteroscopy and holmium lasertripsy.

MATERIALS AND METHODS

A systematic review and quantitative meta-analysis was performed using studies identified by a literature search from 1990s (the first reported large renal stones treated ureteroscopically) to August 2011. All English language articles reporting on a minimum of 10 patients treated with FURSL for renal stones >2 cm were included. Two reviewers independently extracted the data from each study. The data of studies with comparable results were included into a meta-analysis.

RESULTS

In nine studies, 445 patients (460 renal units) were reportedly treated with FURSL. The mean operative time was 82.5 minutes (28-215 min). The mean stone-free rate was 93.7% (77%-96.7%), with an average of 1.6 procedures per patient. The mean stone size was 2.5 cm. An overall complication rate was 10.1%. Major complications developed in 21 (5.3%) patients and minor complications developed in 19 (4.8%) patients. A subgroup analysis shows that FURSL has a 95.7% stone-free rate with stones 2-3 cm and 84.6% in those >3 cm (P=0.01), with a minor complication rate of 14.3% and 15.4%, respectively, and a major complication rate of 0% and 11.5%, respectively.

CONCLUSION

In experienced hands, FURSL can successfully treat patients with stones >2 cm with a high stone-free rate and a low complication rate. Although the studies are from high-volume experienced centers and may not be sufficient to alter everyday routine practice, this review has shown that the efficacy of FURSL allows an alternative to PCNL.

Ureteroscopic treatment of larger renal calculi (>2 cm)

Objectives

To evaluate the current status of ureteroscopic lithotripsy (UL) for treating renal calculi of >2 cm, as advances in flexible ureteroscope design, accessory instrumentation and lithotrites have revolutionised the treatment of urinary calculi. While previously reserved for ureteric and small renal calculi, UL has gained an increasing role in the selective management of larger renal stone burdens.

Methods

We searched the available databases, including PubMed, Google Scholar, and Scopus, for relevant reports in English, and the article bibliographies to identify additional relevant articles. Keywords included ureteroscopy, lithotripsy, renal calculi, and calculi >2 cm. Retrieved articles were reviewed to consider the number of patients, mean stone size, success rates, indications and complications.

Results

In all, nine studies (417 patients) were eligible for inclusion. After one, two or three procedures the mean (range) success rates were 68.2 (23–84)%, 87.1 (79–91)% and 94.4 (90.1–96.7)%, respectively. Overall, the success rate was >90% with a mean of 1.2–2.3 procedures per patient. The overall complication rate was 10.3%, including six (1.4%) intraoperative and 37 (8.9%) postoperative complications, most of which were minor. The most common indications for UL were a failed previous treatment (46%), comorbidities (18.2%), and technical and anatomical factors (12.3%).

Conclusions

UL is safe and effective for treating large renal calculi. While several procedures might be required for total stone clearance, UL should be considered a standard approach in the urologist’s options treating renal calculi of >2 cm.