Indications, preferences, global practice patterns and outcomes in retrograde intrarenal surgery (RIRS) for renal stones in adults: results from a multicenter database of 6669 patients of the global FLEXible ureteroscopy Outcomes Registry (FLEXOR)

Comparing thulium fiber versus high power holmium laser in bilateral same sitting retrograde intrarenal surgery for kidney stones: Results from a multicenter study

PURPOSE

Traditionally, bilateral urolithiasis treatment involved staged interventions due to safety concerns. Recent studies have shown that same-sitting bilateral retrograde intrarenal surgery (SSB-RIRS) is effective, with acceptable complication rates. However, there's no clear data on the optimum laser for the procedure. This study aimed to assess outcomes of SSB-RIRS comparing thulium fiber laser (TFL) and high-power holmium:yttrium-aluminum-garnet (Ho:YAG) laser in a multicenter real-world practice.

MATERIALS AND METHODS

Retrospective analysis was conducted on patients undergoing SSB-RIRS from January 2015 to June 2022 across 21 centers worldwide. Three months perioperative and postoperative outcomes were recorded, focusing on complications and stone-free rates (SFR).

RESULTS

A total of 733 patients were included, with 415 in group 1 (Ho:YAG) and 318 in group 2 (TFL). Both groups have similar demographic and stone characteristics. Group 1 had more incidence of symptomatic pain or hematuria (26.5% vs. 10.4%). Operation and lasing times were comparable. The use of baskets was higher in group 1 (47.2% vs. 18.9%, p<0.001). Postoperative complications and length of hospital stay were similar. Group 2 had a higher overall SFR. Multivariate regression analysis indicated that age, presence of stone at the lower pole, and stone diameter were associated with lower odds of being stone-free bilaterally, while TFL was associated with higher odds.

CONCLUSIONS

Our study shows that urologists use both lasers equally for SSB-RIRS. Reintervention rates are low, safety profiles are comparable, and single-stage bilateral SFR may be better in certain cases. Bilateral lower pole and large-volume stones have higher chances of residual fragments.

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.

Fabrication of acoustically and physically validated artificial stones to natural kidney stones under shock waves and laser lithotripsy

To present an efficient method for fabricating artificial kidney stones with acoustic and physical properties to assess their fragmentation efficiency under shock waves and laser lithotripsy for very hard stones. The mixture ratio of super-hard plaster and water was adjusted to produce artificial kidney stones for comparison with > 95% human genuine calcium oxalate monohydrate (COM) and uric acid (UA) stones. Acoustic and physical properties, such as wave speed, stone hardness, density, compressive strength, and stone-free rates under shock-wave and laser lithotripsy, were assessed. The longitudinal wave speed of artificial stones prepared at a plaster-to-water ratio of 15:3 closely matched that of COM stones. Similarly, the transverse wave speed of artificial stones prepared at a plaster-to-water ratio of 15:3 to 15:5 aligned with that of COM stones. Stone fragmentation using shock-wave of artificial stones with mixed ratios ranging from 15:3 to 15:5 resembled that of COM stones. The Vickers hardness was similar to that of artificial stones produced with a mixing ratio of 15:3, similar to that of COM stones, while that of artificial stones produced with a mixing ratio of 15:5 was similar to that of UA stones. Density-wise, artificial stones with mixing ratios of 15:4 and 15:5 resembled COM stones. Compressive strength test results did not confirm the similarity between natural and artificial stones. The stone fragmentation using laser showed that stones produced with higher moisture content at a mixing ratio of 15:6 were similar to COM stones. This novel method for fabricating artificial kidney stones could be used to provide reliable materials for lithotripsy research.

Retrograde intrarenal surgery for asymptomatic incidental renal stones: a retrospective, real-world data analysis

OBJECTIVE

To determine surgical outcomes and stone-free rates (SFRs) when offering upfront retrograde intrarenal surgery (RIRS) to patients with asymptomatic incidental renal stones (AIRS), as active surveillance, shockwave lithotripsy or upfront intervention in patients with AIRS is still a debate among urologists.

PATIENTS AND METHODS

This retrospective FLEXible Ureteroscopy Outcomes Registry (FLEXOR), supported by the Team of Worldwide Endourological Researchers (TOWER), examines adult patients who underwent RIRS. We analysed a subset of asymptomatic patients with renal stones on imaging who were treated with RIRS. Data includes patient characteristics, stone specifications, anaesthesia type, perioperative details, complications, and SFR. A multivariable logistic regression analysis was performed to assess factors associated with the SFR.

RESULTS

Among 679 patients with AIRS, 640 met the inclusion criteria. The median age was 55 years, with 33.4% being female. In all, 22.1% had positive urine cultures. The median stone diameter was 12 mm, commonly in lower and interpolar locations. RIRS was preferentially performed under general anaesthesia using a reusable scope in 443 cases. Prophylactic antibiotics were administered to 314 patients. The median operation time was 58 min and the median laser time was 24 min. The SFR was 68.8%. The use of holmium laser (odds ratio [OR] 0.21, 95% confidence interval [CI] 0.06-0.63; P < 0.01) and multiple stones (OR 0.38, 95% CI 0.19-0.76; P < 0.01) were factors associated with lower odds of being stone free. Overall complications were minimal, with sepsis in 1.6% of patients. Re-interventions were performed in 76 cases (11.8%), with RIRS being the most common in 67 cases (10.6%).

CONCLUSION

Our multicentre real-world study is the first of its kind that highlights the pros and cons of offering RIRS to patients with AIRS and demonstrates a favourable SFR with acceptable complications. Pre-emptively discussing potential re-intervention helps patients make informed decisions, particularly in cases involving large and multiple stones.

Could Use of a Flexible and Navigable Suction Ureteral Access Sheath Be a Potential Game-changer in Retrograde Intrarenal Surgery? Outcomes at 30 Days from a Large, Prospective, Multicenter, Real-world Study by the European Association of Urology Urolithiasis Section

BACKGROUND AND OBJECTIVE

The aim of this study was to evaluate the stone-free status (SFS) rate and complications after flexible ureteroscopy (fURS) for treatment of renal stones using a flexible and navigable suction (FANS) ureteral access sheath.

METHODS

Data for adults undergoing fURS in 25 centers worldwide were prospectively collected (August 2023 to January 2024). Exclusion criteria were abnormal renal anatomy and ureteral stones. All patients had computed tomography scans before and within 30 d after fURS with a FANS ureteral access sheath. SFS was defined as follows: grade A, zero fragments; grade B, a single fragment ≤2 mm; grade C, a single fragment 2.1-4 mm; and grade D, single/multiple fragments >4 mm. Data for continuous variables are presented as the median and interquartile range (IQR). Multivariable logistic regression was performed to evaluate predictors of grade A SFS.

KEY FINDINGS AND LIMITATIONS

The study enrolled 394 patients (59.1% male) with a median age of 49 yr (IQR 36-61). The median stone volume was 1260 mm3 (IQR 706-1800). Thulium fiber laser (TFL) was used in 45.9% of cases and holmium laser in the rest. The median lasing time was 18 min (IQR 11-28) and the median operative time was 49 min (IQR 37-70). One patient required a blood transfusion and 3.3% of patients had low-grade fever. No patient developed sepsis. Low-grade ureteral injury occurred in eight patients (2%). The grade A SFS rate was 57.4% and the grade A + B SFS rate was 97.2%, while 2.8% of patients had grade C or D SFS. Eleven patients underwent repeat fURS. Multivariable analysis revealed that a stone volume of 1501-3000 mm3 (odds ratio 0.50) and of >3000 mm3 (odds ratio 0.29) were significantly associated with lower probability of grade A SFS, while TFL use was associated with higher SFS probability (odds ratio 1.83). Limitations include the lack of a comparative group.

CONCLUSIONS AND CLINICAL IMPLICATIONS

fURS using a FANS ureteral access sheath resulted in a high SFS rate with negligible serious adverse event and reintervention rates.

PATIENT SUMMARY

We looked at 30-day results for patients undergoing telescopic laser treatment for kidney stones using a special type of vacuum-assisted sheath to remove stone fragments. We found a high stone-free rate with minimal complications.

Play it safe: renal function after bilateral flexible ureteroscopy for kidney stones

PURPOSE

We searched for perioperative renal function deterioration risk factors in patients that underwent bilateral flexible ureteroscopy (fURS) for kidney stones.

METHODS

From August 2016 to February 2020, symptomatic patients > 18 years old with bilateral kidney stones up to 20 mm in each side were prospectively studied. Serum creatinine samples were collected on admission to surgery, immediate postoperative (IPO), on POD 3, 10, and 30. Estimated glomerular filtration rate (eGFR) was calculated using Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI) without a race coefficient.

RESULTS

Thirty patients underwent bilateral fURS. Comparing to preoperative eGFR, median IPO and POD3 eGFR (p < 0.001) were significantly lower, and POD10 (p = 0.092) and POD30 (p = 0.648) were similar to preoperative eGFR. During follow-up, 22/30 (73.3%), 14/30 (46.7%), and 7/30 (23.3%) of the patients presented a decrease > 10% eGFR, > 20% eGFR, and > 30% eGFR, respectively. Multivariate analysis demonstrated that lower preoperative eGFR is a risk factor for eGFR < 60 mL/min/1.73 m2, p = 0.019 [1.021-1.263; 1.136]; ASA > 1 is a risk factor for decrease of eGFR > 10%, p = 0.028 [1.25-51.13; 8.00]; longer operative time is a risk factor for decrease of eGFR > 20%, p = 0.042 [1.00-1.05; 1.028]; and operative time ≥ 120 min is a risk factor for decrease of eGFR > 30%, p = 0.026 [0.016-0.773; 0.113].

CONCLUSIONS

Renal function suffers a reversible decrease after bilateral fURS. Our study suggests that adequate selection of patients and maintaining operative time < 120 min are relevant factors in preventing acute renal function deterioration following bilateral fURS.

Comparing Same-Sitting Bilateral vs Unilateral Retrograde Intrarenal Surgery in the Elderly

OBJECTIVE

To compare same-sitting bilateral vs unilateral retrograde intrarenal surgery (RIRS) in elderly patients, focusing on postoperative complications and stone-free rates (SFR).

METHODS

Data from 2 multicenter databases, FLEXible ureteroscopy Outcomes Registry (FLEXOR) (unilateral RIRS) and same sitting bilateral-retrograde intrarenal surgery (SSB-RIRS) (bilateral RIRS), were analyzed, considering only patients aged 70+ with preoperative computed tomography. Patients were categorized into Group 1 (bilateral RIRS) and Group 2 (unilateral RIRS). Follow-up included imaging assessments and secondary treatments as needed.

RESULTS

Group 1 included 146 patients, while group 2 had 495. Group 1's patients were slightly older and had a higher prevalence of recurrent stone formation. Group 2 often underwent RIRS for incidental stones. Group 1 had larger and more pelvic stones. Laser lithotripsy and total operation times were significantly longer in Group 1. Group 2 had significantly higher overall stone-free rates, although there were no significant differences in ancillary procedures for residual fragments. Group 1 experienced more pelvicalyceal injuries needing stenting, postoperative fever, and post-op hematuria not requiring transfusion.

CONCLUSION

In conclusion, bilateral RIRS can be carefully considered in elderly patients. Preoperative counseling is essential for both primary and repeat RIRS procedures, and further research is needed to optimize instrument and laser strategies for better outcomes in elderly RIRS patients.

Suction in Percutaneous Nephrolithotripsy: Evolution, Development, and Outcomes from Experimental and Clinical studies. Results from a Systematic Review

CONTEXT

Controversy exists regarding the therapeutic benefit of suction use during percutaneous nephrolithotripsy (PCNL).

OBJECTIVE

To review and highlight the options available in the use of suction for PCNL, and to discuss their strengths and limitations.

EVIDENCE ACQUISITION

A systematic literature search was performed using Scopus, EMBASE, and PubMed. Thirty four studies were included. There was one ex vivo study. Among clinical studies, 24 used a vacuum/suctioning sheath and nine a handpiece suction device/direct-in-scope suction. The suction technique was employed in standard, mini-PCNL, supermini-PCNL, and enhanced supermini‑PCNL techniques.

EVIDENCE SYNTHESIS

Handpiece suction devices demonstrated better safety and efficiency in treating large stones than nonsuction PCNL and in a much shorter time. Trilogy and ShockPulse-SE were equally effective, safe, and versatile for standard PCNL and mini-PCNL. The heavier handpiece makes Trilogy less ergonomically friendly. Laser suction handpiece devices can potentiate laser lithotripsy by allowing for better laser control with simultaneous suction of small fragments and dust. Integrated suction-based sheaths are available in reusable and disposable forms for mini-PCNL only. Mini-PCNL with suction reported superior outcomes for operative time and stone-free rate to mini-PCNL. This also helped minimize infectious complications by a combination of intrarenal pressure reduction and faster aspiration of irrigation fluid reducing the risk of sepsis, enhance intraoperative vision, and improve lithotripsy efficiency, which makes it a very attractive evolution for PCNL.

CONCLUSIONS

Suction devices in PCNL are reforming the way PCNL is being done. Adding suction to mini-PCNL reduces infectious complications and improves the stone-free rate. Our review shows that despite the limited evidence, suction techniques appear to improve PCNL outcomes.

PATIENT SUMMARY

In this review, we looked at the intra- and perioperative outcomes of percutaneous nephrolithotripsy (PCNL) with the addition of suction. With better stone fragmentation and fewer postoperative infections, this technology is very useful particularly for mini-PCNL.

Experimental and clinical applications and outcomes of using different forms of suction in retrograde intrarenal surgery. Results from a systematic review

OBJECTIVE

To identify the latest advances in suction devices and evaluate their effect in Retrograde intrarenal surgery (RIRS) and ureteroscopy for stones.

BASIC PROCEDURES

A systematic literature search was performed on 4th January 2023 using Scopus, PubMed, and EMBASE. Only English papers were included; both pediatric and adult studies were accepted. Duplicate studies, case reports, letters to the editor, and meeting abstracts were excluded.

MAIN FINDINGS

Twenty-one papers were selected. Several methods have been proposed for suction use in RIRS, such as through the ureteral access sheath or directly to the scope. Artificial intelligence can also regulate this system, monitoring pressure and perfusion flow values. All the proposed techniques showed satisfactory perioperative results for operative time, stone-free rate (SFR), and residual fragments. Moreover, the reduction of intrarenal pressure (induced by aspiration) was also associated with a lower infection rate. Even the studies that considered kidney stones with a diameter of 20 mm or higher reported higher SFR and reduced postoperative complications. However, the lack of well-defined settings for suction pressure and fluid flow prevents the standardization of the procedure.

CONCLUSION

Aspiration device in the surgical treatment of urinary stones favours a higher SFR, reducing infectious complications, as supported by the included studies. RIRS with a suction system provided to be a natural successor to the traditional technique, regulating intrarenal pressure and aspirating fine dust.

Do Hounsfield Units have any significance in predicting intra- and postoperative outcomes in retrograde intrarenal surgery using Holmium and Thulium fiber laser? Results from the FLEXible ureteroscopy Outcomes Registry (FLEXOR)

PURPOSE

To evaluate outcomes of flexible ureteroscopy for renal stones by comparing hard versus soft stones based on their attenuation on computed tomography (Hounsfield Units-HU).

METHODS

Patients were divided into two groups according to the type of laser employed [Holmium:YAG (HL) or Thulium fiber laser (TFL)]. Residual fragments (RF) were defined as > 2 mm. Multivariable logistic regression analysis was performed to evaluate factors associated with RF and RF needing further intervention.

RESULTS

4208 patients from 20 centers were included. In whole series, age, recurrent stones, stone size, lower pole stones (LPS), and multiple stones were predictors of RF at multivariable analysis and LPS and stone size with RF requiring further treatment. HU and TFL were associated with lesser RF and RF requiring an additional treatment. In HU < 1000 stones, recurrent stones, stone size, and LPS were predictors of RF at multivariable analysis, whereas TFL was less likely associated with RF. Recurrent stones, stone size, and multiple stones were predictors of RF requiring further treatment, while LPS and TFL were associated with lesser RF requiring further treatment. In HU ≥ 1000 stones, age, stone size, multiple stones, and LPS were predictors of RF at multivariable analysis, while TFL was less likely associated with RF. Stone size and LPS were predictors of RF requiring further treatment, whereas TFL was associated with RF requiring further treatment.

CONCLUSION

Stone size, LPS, and use of HL are predictors of RF after RIRS for intrarenal stones regardless of stone density. HU should be considered an important parameter in predicting SFR.

Does age impact outcomes of retrograde intrarenal surgery in the elderly? Results from 366 patients from the FLEXible ureteroscopy outcomes registry (FLEXOR)

BACKGROUND

There has been a consistent increase in the last decades in prevalence of renal stones in elderly.

AIMS

To evaluate outcomes of retrograde intrarenal surgery (RIRS) for renal stones in elderly and factors associated with postoperative complications and residual fragments (RFs).

METHODS

Data from 12 centers were retrospectively reviewed.

INCLUSION CRITERIA

 ≥ 75 years, renal stones only, normal renal anatomy. Patients were divided into three groups; Group 1: patients aged 75-79 years; Group 2: age 80-84 years; Group 3: age ≥ 85 years. Multivariable logistic regression analyses were performed to assess factors associated with perioperative complications, sepsis, and RFs.

RESULTS

366 patients were included. There were 189 patients in Group 1, 113 in Group 2, and 64 in Group 3. There was no difference between groups regarding stone features and total surgical time. Median length of stay was significantly longer in Group 3 (6.0 days, vs 2.0 days in Group 2 vs 2.5 days in Group 1, p = 0.043). There was no significant difference in postoperative complications and RFs between the groups. At multivariable logistic regression analysis, female gender (OR 2.82) and maximum stone diameter (OR 1.14) were associated with higher odds of sepsis, while surgical time (OR 1.12) and the use of a reusable ureteroscope (OR 6.51) with overall complications. Stone size (OR 1.23) was associated with higher odds of RFs.

CONCLUSION

RIRS showed safety and efficacy for kidney stones in elderly patients. Surgical time should be kept as short as possible to avoid higher odds of postoperative complications, particularly in females.

Results from a global multicenter registry of 6193 patients to refine endoscopic anatomical enucleation of the prostate (REAP) by evaluating trends and outcomes and nuances of prostate enucleation in a real-world setting

PURPOSE

To collect a multicentric, global database to assess current preferences and outcomes for endoscopic enucleation of the prostate (EEP).

METHODS

Endourologists experienced in EEP from across the globe were invited to participate in the creation of this retrospective registry. Surgical procedures were performed between January 2020 and August 2022.

INCLUSION CRITERIA

lower urinary tract symptoms not responding to or worsening despite medical therapy and absolute indication for surgery.

EXCLUSION CRITERIA

prostate cancer, concomitant lower urinary tract surgery, previous prostate/urethral surgery, pelvic radiotherapy.

RESULTS

Ten centers from 7 countries, involving 13 surgeons enrolled 6193 patients. Median age was 68 [62-74] years. 2326 (37.8%) patients had large prostates (> 80 cc). The most popular energy modality was the Holmium laser. The most common technique used for enucleation was the 2-lobe (48.8%). 86.2% of the procedures were performed under spinal anesthesia. Median operation time was 67 [50-95] minutes. Median postoperative catheter time was 2 [1, 3] days. Urinary tract infections were the most reported complications (4.7%) followed by acute urinary retention (4.1%). Post-operative bleeding needing additional intervention was reported in 0.9% of cases. 3 and 12-month follow-up visits showed improvement in symptoms and micturition parameters. Only 8 patients (1.4%) required redo surgery for residual adenoma. Stress urinary incontinence was reported in 53.9% of patients and after 3 months was found to persist in 16.2% of the cohort.

CONCLUSION

Our database contributes real-world data to support EEP as a truly well-established global, safe minimally invasive intervention and provides insights for further research.

PCNL vs RIRS in management of stones in calyceal diverticulum: outcomes from a global multicentre match paired study that reflects real world practice

INTRODUCTION

Calyceal diverticulum (CD) is the outpouching of a calyx into the renal parenchyma, connected by an infundibulum. Often associated with recurrent stones, common surgical options include percutaneous nephrolithotomy (PCNL) or retrograde intrarenal surgery (RIRS). We aim to present the real-world practises and outcomes comparing both approaches and the technical choices made.

MATERIALS AND METHODS

Retrospective data including 313 patients from 11 countries were evaluated. One hundred and twenty-seven underwent mini-PCNL and one hundred and eighty-six underwent RIRS. Patient demographics, perioperative parameters, and outcomes were analysed using either T test or Mann-Whitney U test. Categorical data between groups were analysed using the Chi-squared test. Propensity score matching (PSM) was performed matching for baseline characteristics. Subgroup analyses for anomalous/malrotated kidneys and difficult diverticulum access were performed.

RESULTS

After PSM, 123 patients in each arm were included, with similar outcomes for stone-free rate (SFR) and complications (p < 0.001). Hospitalisation was significantly longer in PCNL. Re-intervention rate for residual fragments (any fragment > 4 mm) was similar. RIRS was the preferred re-intervention for both groups. Intraoperative bleeding was significantly higher in PCNL (p < 0.032) but none required transfusion. Two patients with malrotated anatomy in RIRS group required transfusion. Lower pole presented most difficult access for both groups, and SFR was significantly higher in difficult CD accessed by RIRS (p < 0.031). Laser infundibulotomy was preferred for improving diverticular access in both. Fulguration post-intervention was not practised.

CONCLUSION

The crux lies in identification of the opening and safe access. Urologists may consider a step-up personalised approach with a view of endoscopic combined approach where required.

A Novel Distal Active Flexible Vacuum-assisted Ureteric Access Sheath in Retrograde Intrarenal Surgery

INTRODUCTION

Retrograde intrarenal surgery (RIRS) is one of the primary treatments for renal stones. The ureteral access sheath (UAS) was widely used in RIRS.1,2 The aim of this paper is to introduce a new UAS, the distal active flexible vacuum-assisted ureteral access sheaths (DAFV-UAS), for the renal calculus during RIRS.

CASE PRESENTATION

A 56-year-old female presented to the outpatient clinics of our hospital with a left renal lower calyx stone. Abdominal CT demonstrated that the left kidney's lower calyx stone size was 10.54 ×10.38 mm, and the mean Hounsfield density was 965HU. After adequate anti-infective treatment, the DAFV-UAS was used in RIRS. No perioperative complications were observed. The left renal stone had been cleared completely.

DISCUSSION

The DAFV-UAS (10/12.5 Fr, 38 cm, creek, Jiangsu, China) includes a good flexibility and deformability tube at the tip, about 10 cm long. It has an active bending function, negative pressure suction function, and the function of convenient flexible ureteroscopy (f-URS) entry and exit of the ureter.3 In this case, the f-URS adopted a 7.5 Fr single-use digital f-URS. The Irrigation method was automated irrigation system, and the flow was 30 mL/min. The suction level was 0.02mpa. With the help of DAFV-UAS, the field of view is always clean, the small gravel particles can be sucked out from the sheath gap, and the larger gravel particles are sucked out by withdrawing the scope intermittently.

CONCLUSION

DAFV-UAS is a promising new device which allows for negative pressure suction directed right at a renal stone and efficient and effective stone clearance.

Influence of pre-stenting on RIRS outcomes. Inferences from patients of the Global Multicentre Flexible Ureteroscopy Outcome Registry (FLEXOR)

BACKGROUND

Retrograde Intrarenal Surgery (RIRS) is recommended as an alternative to percutaneous nephrolithotomy for stones up to 2 cm. Pre-stenting before RIRS remains controversial with various studies differing in outcomes and recommendations. We aim to understand how pre-stenting influences surgical outcomes.

METHODS

A number of 6579 patients from the TOWER group registry were divided into pre-stented (group 1) and non-pre-stented groups (group 2). Patients aged ≥18 years old, with normal calyceal anatomy were enrolled. Patients with ureteric stones, anomalous kidneys, bilateral stones, planned for ECIRS were excluded.

RESULTS

Patients are homogeneously distributed in both groups (3112 vs. 3467). The predominant indication for pre-stenting was symptom relief. Overall stone size was comparable, whilst group 1 had a significantly more multiple (1419 vs. 1283, P<0.001) and lower-pole (LP) stones (1503 vs. 1411, P<0.001). The mean operative time for group 2 was significantly longer (68.17 vs. 58.92, P<0.001). Stone size, LP stones, age, recurrence and multiple stones are contributing factors for residual fragments at the multivariable analysis. The incidence of postoperative day 1 fever and sepsis was significantly higher in group 2, indicating that pre-stenting is associated with a lower risk of post-RIRS infection and a lower overall complications rate (13.62% vs. 15.89%) (P<0.001).

CONCLUSIONS

RIRS without pre-stenting can be considered safe without significant morbidity. Multiple, lower-pole and large stone is a significant contributor towards residual fragments. Patients who were not pre-stented had significantly higher but low-grade complications, especially for lower pole and large volume stones. While we do not advocate routine pre-stenting, a tailored approach for these patients should include proper counselling regarding pre-stenting.

Improving Outcomes of Same-sitting Bilateral Flexible Ureteroscopy for Renal Stones in Real-world Practice-Lessons Learnt from Global Multicenter Experience of 1250 Patients

Background

Bilateral kidney stones are commonly treated in staged procedures.

Objective

To evaluate outcomes after same-sitting bilateral retrograde intrarenal surgery (SSB-RIRS) for renal stones.

Design setting and participants

Data from adults who underwent bilateral RIRS in 21 centers were retrospectively reviewed (from January 2015 to June 2022). The inclusion criteria were unilateral/bilateral symptomatic bilateral stone(s) of any size/location in both kidneys and bilateral stones on follow-up with symptom/stone progression. Stone-free rate (SFR) was defined as absence of any fragment >3 mm at 3 mo.

Outcome measurements and statistical analysis

Continuous variables are presented as medians and 25-75th percentiles. A multivariable logistic regression analysis was performed to evaluate independent predictors of sepsis and bilateral SFR.

Results and limitations

A total of 1250 patients were included. The median age was 48.0 (36-61) yr. Of the patients, 58.2% were prestented. The median stone diameter was 10 mm on both sides. Multiple stones were present in 45.3% and 47.9% of the left and right kidneys, respectively. Surgery was stopped in 6.8% of cases. The median surgical time was 75.0 (55-90) min. Complications were transient fever (10.7%), fever/infection needing prolonged stay (5.5%), sepsis (2%), and blood transfusion (1.3%). Bilateral and unilateral SFRs were 73.0% and 17.4%, respectively. Female (odds ratio [OR] 2.97, 95% confidence interval [CI] 1.18-7.49, p = 0.02), no antibiotic prophylaxis (OR 5.99, 95% CI 2.28-15.73, p < 0.001), kidney anomalies (OR 5.91, 95% CI 1.96-17.94, p < 0.001), surgical time ≥100 min (OR 2.86, 95% CI 1.12-7.31, p = 0.03) were factors associated with sepsis. Female (OR 1.88, 95% CI 1.35-2.62, p < 0.001), bilateral prestenting (OR 2.16, 95% CI 1.16-7.66, p = 0.04), and the use of high-power holmium:YAG laser (OR 1.63, 95% CI 1.14-2.34, p < 0.01) and thulium fiber laser (OR 2.50, 95% CI 1.32-4.74, p < 0.01) were predictors of bilateral SFR. Limitations were retrospective study and no cost analysis.

Conclusions

SSB-RIRS is an effective treatment with an acceptable complication rate in selected patients with kidney stones.

Patient summary

In this large multicenter study, we looked at outcomes after same-sitting bilateral retrograde intrarenal surgery (SSB-RIRS) for renal stones in a large cohort. We found that SSB-RIRS was associated with acceptable morbidity and good stone clearance after a single session.

The efficacy of retrograde intra-renal surgery (RIRS) for lower pole stones: results from 2946 patients

PURPOSE

To evaluate the perioperative outcomes of retrograde intra-renal surgery (RIRS) for lower pole stones (LPS) and factors affecting stone-free rate (SFR).

METHODS

Data from 20 centers were retrospectively reviewed. Inclusion criteria were adult patients, normal renal anatomy, and LPS. Exclusion criteria were bilateral surgery, concomitant surgery for ureteral stones. SFR was defined as a single residual fragment (RF) ≤ 2 mm and evaluated 3-months after surgery. A multivariable logistic regression analysis was performed to assess factors associated with RF. Statistical significance was set at p value < 0.05.

RESULTS

2946 patients were included. Mean age and stone size were 49.9 years 10.19 mm, with multiple LPS in 61.1% of cases. Total operation and laser time were 63.89 ± 37.65 and 17.34 ± 18.39 min, respectively. Mean hospital stay was 3.55 days. Hematuria requiring blood transfusion and fever/urinary infections requiring prolonged antibiotics occurred in 6.1% and 169 5.7% of cases, while sepsis with intensive-care admission in 1.1% of patients. On multivariate analysis, Multiple stones (OR 1.380), stone size (OR 1.865), and reusable ureteroscopes (OR 1.414) were significantly associated with RF, while Thulium fiber laser (TFL) (OR 0.341) and pre-stenting (OR 0.750) were less likely associated with RF.

CONCLUSIONS

RIRS showed safety and efficacy for LPS with a mean diameter of 10 mm. This procedure can achieve a satisfactory SFR in pre-stented patients with a single and smaller stone, particularly with TFL use.

Does unenhanced computerized tomography as imaging standard post-retrograde intrarenal surgery paradoxically reduce stone-free rate and increase additional treatment for residual fragments? Outcomes from 5395 patients in the FLEXOR study by the TOWER group

Background

Assessment of residual fragments (RFs) is a key step after treatment of kidney stones.

Objective

To evaluate differences in RFs estimation based on unenhanced computerized tomography (CT) versus X-rays/ultrasound after retrograde intrarenal surgery (RIRS) for kidney stones.

Design

A retrospective analysis of data from 20 centers of adult patients who had RIRS was done (January 2018-August 2021).

Methods

Exclusion criteria: ureteric stones, anomalous kidneys, bilateral renal stones. Patients were divided into two groups (group 1: CT; group 2: plain X-rays or combination of X-rays/ultrasound within 3 months after RIRS). Clinically significant RFs (CSRFs) were considered RFs ⩾ 4 mm. One-to-one propensity score matching for age, gender, and stone characteristics was performed. Multivariable logistic regression analysis was performed to evaluate independent predictors of CSRFs.

Results

A total of 5395 patients were included (1748 in group 1; 3647 in group 2). After matching, 608 patients from each group with comparable baseline and stone characteristics were included. CSRFs were diagnosed in 1132 patients in the overall cohort (21.0%). Post-operative CT reported a significantly higher number of patients with RFs ⩾ 4 mm, before (35.7% versus 13.9%, p < 0.001) and after matching (43.1% versus 23.9%, p < 0.001). Only 21.8% of patients in the matched cohort had an ancillary procedure post-RIRS which was significantly higher in group 1 (74.8% versus 47.6%, p < 0.001). Age [OR 1.015 95% confidence interval (CI) 1.009-1.020, p < 0.001], stone size (OR 1.028 95% CI 1.017-1.040, p < 0.001), multiple stones (OR 1.171 95% CI 1.025-1.339, p = 0.021), lower pole stone (OR 1.853 95% CI 1.557-2.204, p < 0.001) and the use of post-operative CT scan (OR 5.9883 95% CI 5.094-7.037, p < 0.001) had significantly higher odds of having CSRFs.

Conclusions

CT is the only reliable imaging to assess the burden of RFs following RIRS and urologist should consider at least one CT scan to determine the same and definitely plan reintervention only based on CT rather than ultrasound and X-ray combination.