The Prime Time for Flexible Ureteroscopy for Large Renal Stones Is Coming: Is Percutaneous Nephrolithotomy No Longer Needed?

Percutaneous nephrolithotomy versus retrograde intrarenal surgery on mid-sized lower calyx stones- a systematic review of last decade

BACKGROUND

To systematically assess the effectiveness and safety of retrograde intrarenal surgery (RIRS) versus percutaneous nephrolithotomy (PCNL) in treating lower pole stones.

METHODS

PubMed, Ovid MEDLINE, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL), and EMBASE were researched to identify relevant studies up to May 2018. Based on keyword searches, we explored 1972 studies; following screening and eligibility evaluation, 414 studies were removed for various reasons, including 11 possibly relevant studies for this systematic review. A total of 1342 patient data were interpreted (PCNLn = 688; RIRS n = 654).

RESULTS

The stone-free rate (SFR) in ten studies following the PCNL operation varies from 68 to 98.3%, while after the RIRS procedure, it ranges from around 46-93.7%. Out of 10 investigations, 7 demonstrated a superior SFR for the PCNL technique compared to the RIRS. Of the ten investigations, eight demonstrated reduced surgical durations using the PCNL method compared to the RIRS procedure. The duration of hospital stays for the PCNL treatment varies from around 0.3 ± 0.04 to 5.3 ± 1.20 days, while the duration for RIRS procedures ranges from 0 to 3.2 ± 0.52 days. All nine trials indicated a reduced period of hospital stay with the RIRS technique compared to the PCNL procedure. The complication rates in 10 studies following the PCNL surgery varied from approximately 2-72%, while those after the RIRS procedure ranged from about 4-21.6%. Out of 10 trials, 6 demonstrated a reduced complication rate with the RIRS technique compared to the PCNL.

CONCLUSION

The majority of studies in this systematic review indicate that the PCNL method exhibits a superior SFR, reduced operational duration, prolonged hospital stay, and increased complication rates compared to the RIRS procedure.

CLINICAL TRIAL NUMBER

Not applicable, as this is a systematic review.

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.

Small Diameter (7.5 Fr) Single-Use Flexible Ureteroscopy with Direct In-Scope Suction (DISSTM) in Conjunction with Aspiration-Assisted Flexible Access Sheath: A New Hype for Real Stone-Free?

Background: Renal lithiasis continues to represent a great challenge for modern urology in terms of minimally invasive management of lithotripsy procedures. The recent revolution of endoscopes with the miniaturization of instruments and the development of improved disposable ureteroscopes combined with recent suction methods such as suction access sheaths or direct in-scope suction (DISSTM) systems promise to further improve the outcome of renal stone treatment. Methods: Considering this technological advance, this study aims to evaluate the results obtained by combining these methods in three groups: Group 1-Single-use 7.5 Fr flexible ureteroscope with standard access sheath, Group 2-Single-use 7.5 Fr flexible ureteroscope with direct in-scope suction (DISSTM) with standard access sheath, Group 3-Single-use 7.5 Fr flexible ureteroscope with DISSTM with suction access sheath. A total number of 105 consecutive patients were enrolled in the study, divided equally in each group. Several parameters were followed, such as size and location of the stones, operative time, duration of hospitalization, the need for ureteral stent insertion, residual fragments, and subjective evaluation of the lithotripsy environment visualization. Results: The best results were highlighted in Group 3 for almost all evaluated parameters. Significant improvements were indicated in terms of stone-free rates. Conclusions: Additional large studies are needed to support these initial results, but preliminary data indicate a valuable advantage for every urologist who treats urolithiasis.

The infection post flexible UreteroreNoscopy (I-FUN) predictive model based on machine learning: a new clinical tool to assess the risk of sepsis post retrograde intrarenal surgery for kidney stone disease

PURPOSE

To create a machine-learning model for estimating the likelihood of post-retrograde intrarenal surgery (RIRS) sepsis.

METHODS

All consecutive patients with kidney stone(s) only undergoing RIRS in 16 centers were prospectively included (January 2022-August 2023).

INCLUSION CRITERIA

adult, renal stone(s) only, CT scan (within three months), mid-stream urine culture (within 10 days).

EXCLUSION CRITERIA

concomitant ureteral stone, bilateral procedures. In case of symptomatic infection/asymptomatic bacteriuria, patients were given six days of antibiotics according to susceptibility profiles. All patients had antibiotics prophylaxis. Variables selected for the model: age, gender, age-adjusted Charlson Comorbidity Index, stone volume, indwelling preoperative bladder catheter, urine culture, single/multiple stones, indwelling preoperative stent/nephrostomy, ureteric access sheath, surgical time. Analysis was conducted using Python programming language, with Pandas library and machine learning models implemented using the Scikit-learn library. Machine learning algorithms tested: Decision Tree, Random Forest, Gradient Boosting. Overall performance was accurately estimated by K-Fold cross-validation with three folds.

RESULTS

1552 patients were included. There were 20 (1.3%) sepsis cases, 16 (1.0%) septic shock cases, and three more cases (0.2%) of sepsis-related deaths. Random Forest model showed the best performance (precision = 1.00; recall = 0.86; F1 score = 0.92; accuracy = 0.92). A web-based interface of the predictive model was built and is available at https://emabal.pythonanywhere.com/ CONCLUSIONS: Our model can predict post-RIRS sepsis with high accuracy and might facilitate patient selection for day-surgery procedures and identify patients at higher risk of sepsis who deserve extreme attention for prompt identification and treatment.

Safety and efficacy of ureteroscopy and laser lithotripsy with a single-use 7.5Fr ureteroscope: a multicenter prospective pilot study

Introduction

The treatment of kidney stone disease (KSD) has evolved significantly with the introduction of minimally invasive endourological techniques. Advancements in technology, particularly the transition from fibreoptic to digital and single use systems and the development of smaller-diameter instruments, has improved intraoperative view and efficacy in stone treatment. The miniaturization in single-use scopes represent a recent innovation, offering potential benefits, especially in challenging cases. However, there is limited evidence on their safety and clinical outcomes. This study aims to evaluate the efficacy and safety of stone treatment using a single-use 7.5 Fr flexible ureteroscope.

Material and methods

Consecutive patients with urinary stones undergoing flexible ureteroscopy with a 7.5 Fr single-use flexible ureteroscope across five tertiary endourology centers were included. Data on patient demographics, stone characteristics, intra- and postoperative outcomes were prospectively collected and analyzed. Procedures were performed by experienced endourology surgeons following standard protocols.

Results

50 patients with a mean age of 54.5 years (IQR: 25-65.8) and a male to female ratio of 34:16 underwent flexible ureteroscopy (FURS). Mean cumulative stone size was 18.9 mm (SD ±10.9 mm) with a mean stone volume of 2031.2 mm3 (SD ±2869.4 mm3) and mean Hounsfield units of 1087.4 (SD ±384.9). 36 (72%) had multiple stones and a bilateral FURS was performed in 9 cases (18%). 24 patients (48%) had a preoperative stent inserted. A ureteral access sheath was used in 22 (44%) cases and 46 (92%) patients had a postoperative stent inserted. The median operative time was 60min (IQR: 53-90), 32 patients (64%) were stone free after the first procedure (SFR for <2 cm and ≥2 cm stones was 85.2% and 36.2% respectively), perioperative and postoperative complications (Clavien ≤II) were observed in 3 patients (6%).

Conclusions

This multicentric study demonstrates the safety and efficacy of using the 7.5Fr single-use flexible ureteroscope for urinary stone treatment. While the results are promising, larger studies are needed to validate these findings further.

Successful Treatment of Multiple Large Intrarenal Stones in a 2-Year-Old Boy Using a Single-Use Flexible Ureteroscope and High-Power Laser Settings

The standard treatment procedures for managing renal calculi in the pediatric population are similar to those in adults. The application of flexible ureteroscopy has contributed to the increased popularity of retrograde intrarenal surgery (RIRS) as an alternative therapeutic modality that can be successfully applied in children. One of the most significant innovations of the last decade is the introduction of single-use flexible ureteroscopes (fURSs). In this case report, we present the case of a 2-year-old boy with multiple large calculi in his right kidney, which were successfully removed after a single session of RIRS using a 7.5 F single-use fURS and high-power laser settings. The total operative and lithotripsy times were estimated at 90 and 75 min, respectively. No complications were recorded. The hemoglobin loss was calculated at 0.3 mg/dL, while the creatinine level was decreased by 0.1 mg/dL. The urethral catheter was removed on the first postoperative day, and the patient was discharged. The management of multiple or large kidney stones is very challenging in the pediatric population under the age of three years. Convenient preoperative planning and the appropriate use of available equipment may lead to excellent outcomes accompanied by a reduced risk for complications.

The Significance of Stone Culture in the Incidence of Sepsis: Results from a Prospective, Multicenter Study on Infections Post Flexible UreteroreNescopy (I-FUN) and Laser Lithotripsy for Renal Stones

Objective: Sepsis is the most serious complication of flexible ureteroscopy (F-URS) and laser lithotripsy. We assessed the influence of positive stone culture (SC) on major infectious complications (sepsis, septic shock). Methods: This prospective study enrolled adult patients deemed suitable for F-URS and laser lithotripsy from nine centers (January 2022-August 2023). Inclusion criteria were as follows: kidney stone(s), preoperative midstream urine culture (MSUC), stone(s) assessed at computed tomography scan, and SC. Exclusion criteria were as follows: bilateral procedures, ureteral stones, and children. Group 1 included patients with sterile SC. Group 2 included patients with positive SC. Data are presented as median (interquartile range). A multivariable logistic regression analysis was performed to evaluate factors associated with having a positive SC. Results: In total, 293 patients were included. Median age was 51.0 (24) years. There were 167 (57.0%) males. Group 2 included 32 (2.5%) patients. Group 2 patients were significantly older [75.0 (14) vs 51.0 (23) years, p = 0.02]. Stone features were similar. Major infectious complications were higher in Group 2 (15.6% vs 0.4%). One patient died because of sepsis in Group 2. Two out of 6 (33.3%) patients with major infectious complications had the same pathogen in MSUC and SC. In the multivariable regression analysis, diabetes (OR 3.23), symptomatic urinary infections within 3 months before operation (OR 4.82) and preoperative stent/nephrostomy (OR 2.92) were factors significantly associated with higher odds of positive SC. Conclusions: Patients with positive SC have a higher incidence of major infectious complications after F-URS lithotripsy. SC should be performed whenever feasible because there is a poor correlation between MSUC and SC.

Actively extracting kidney stones combined dusting technique can improve SFR of moderate-complexity kidney stones in fURL

PURPOSE

To evaluate the necessity and effectiveness of actively extracting kidney stones with different complexity that have been visually dusted in flexible ureteroscopic lithotripsy (fURL).

METHODS

We retrospectively reviewed the medical records of patients who underwent fURL with dusting technique in established hospitals. A total of 535 cases were divided into the dusting group or the dusting plus basketing group according to the use of stone basket. Their characteristics and operative parameters were collected and analyzed. We used the R.I.R.S. scoring system to classify the complexity of kidney stones and divided these kidney stones into three subgroups, namely, mild-, moderate-, and severe-complexity group. And then, the effectiveness of stone basket in these subgroups was analyzed.

RESULTS

Although using a stone basket significantly reduced re-operation rate (17.8% in dusting group versus 10.2% in dusting plus basketing group, p = 0.013), no significant difference on stone-free rate (SFR) and overall incidence of complications were noticed between groups. After we classified the complexity of kidney stones using the R.I.R.S. scoring system, we found a stone basket was helpful to improve SFR in kidney stones with moderate-complexity that had been visually dusted in fURL (73.5% in dusting group versus 87.3% in dusting plus basketing group, p = 0.002) but had limited influence on SFR in mild (93.8% in dusting group versus 92.6% in dusting plus basketing group, p = 0.783) or severe (28.5% in dusting group versus 34.0% in dusting plus basketing group, p = 0.598)-complexity kidney stones.

CONCLUSION

The use of stone basket should be encouraged in moderate-complexity kidney stones which can be visually dusted in fURL.

Comparative analysis of scoring systems for patients undergoing retrograde intrarenal surgery with isolated lower calyx stones

PURPOSE

It is critical to provide patients with accurate information on potential surgical outcomes during the preoperative phase. Several scoring systems have been developed for this specific purpose. This study aimed to examine the predicted efficacy of scoring systems in patients with isolated lower calyx stones who underwent retrograde intrarenal surgery (RIRS).

METHODS

We performed a retrospective analysis of 85 patients who underwent RIRS for lower calyx stones between 2016 and 2023. The study computed each participant's Resorlu-Unsal Stone score (RUSS), R.I.R.S. scoring system score, Modified Seoul National University Renal Stone Complexity (S-ReSC) score, S.T.O.N.E. score, Ito's nomogram, and T.O.HO score. Residual stones less than 4 mm were classified as clinically insignificant residual fragments (CIRFs) and regarded as successful. Following that, we used receiver-operating characteristic (ROC) curves to compare various scoring systems' success predictions.

RESULTS

The median scores for RUSS, R.I.R.S. scoring system, Modified S-ReSC, S.T.O.N.E., Ito's nomogram, and T.O.HO score were 1 (1), 7 (2), 2 (0), 11 (1), 18 (4), and 7 (1), respectively. When CIRF cases were included, the stone-free rate increased to 80%. Only Ito's nomogram from scoring systems has a statistically significant cut-off value for success in ROC analysis (p = 0.021). In multivariate analysis, stone volume and preoperative hydronephrosis were associated with success (p = 0.004 and p = 0.035, respectively).

CONCLUSION

In the multivariate analysis, none of the scoring systems were significantly associated with success. Hence, a new scoring system must be developed exclusively for patients with isolated lower pole stones undergoing RIRS.

Risk Related to Increasing Indications for Retrograde Intrarenal Surgery

Cite this article as: Mantica G, Ambrosini F, Malinaric R, Calarco A, Terrone C. Risk related to increasing indications for retrograde intrarenal surgery (RIRS). Urol Res Pract. 2024;50(1):66-67.