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

Does intraoperative surgeon reported stone free status (IO-SFS) correlate with CT based post operative stone free status (PO-SFS) in flexible ureteroscopy using flexible and navigable suction ureteral access sheath (FANS) in real-world practice? A prospective global FANS collaborative study group initiative with the section of EAU endourology

BACKGROUND

Flexible and navigable suction ureteral access sheath (FANS) has been proven to improve stone-free rate (SFR) and many studies report high intraoperative 100% stone-free status (IO-SFS) and postoperative 100% stone-free status (PO-SFS). The reliability of IO-SFS vis-à-vis image-proven PO-SFS needs to be evaluated as it has implications on perioperative management.

METHODS

Our prospective, multicenter study enrolled 704 adult patients from 21 centers who underwent FURS with FANS between August 2023 and October 2024. IO-SFS was categorized into three groups: (1) 100% SFR (no dust or fragments), (2) only dust remaining, and (3) both dust and fragments remaining. PO-SFS was assessed via 2 mm non-contrast computed tomography (NCCT) at 30 days and categorized into four grades: Grade A (100% stone-free), Grade B (single ≤ 2 mm residual fragment), Grade C (single 2.1-4 mm), and Grade D (multiple or any > 4 mm). Primary outcome was correlation between intraoperative and postoperative 100% SFS. Secondary outcomes included perioperative complications, reintervention rates, and predictors of residual fragments and perioperative complications.

RESULTS

IO-SFS reported 100% SFR in 395 cases. Postoperative NCCT confirmed a significantly higher SFS (Grade A + B) in this group (99%) compared to 95.8% in the dust only group and 61.1% in the dust and fragments group (p < 0.001). Positive predictive value (PPV) of intraoperative 100% SFR was 99% with post-op NCCT, while negative predictive value (NPV) was only 12.3%. Secondary outcome analysis showed higher stone volumes, lower pole locations, and use of high-power holmium lasers were associated with increased 2-4 mm residual fragments (OR 6.53, p = 0.047). In the 100% SFR group, the use of 12/14 Fr UAS and disposable scopes was significantly higher, with a preferred strategy combining fragmentation, dusting, and aspiration. No cases of sepsis or significant postoperative bleeding were reported due to the use of FANS, with fewer patients requiring post-operative stenting.

CONCLUSION

This study provides robust evidence that surgeon-reported 100% IO-SFS is highly predictive of NCCT-proven postoperative stone-free outcomes, with a PPV of 99%. However, intraoperative detection of residual fragments is less reliable in predicting persistent stone burden, as only 40% of these patients eventually achieved SFS on NCCT. Standardized imaging protocols remain necessary to optimize postoperative management and patient counseling, while avoid unnecessary re-intervention.

Introducing a new device for direct in-scope suction technique during flexible ureteroscopy for kidney stone disease: an EAU Section of Endourology prospective multicenter audit using the GLITZ system

Background

The direct in-scope suction (DISS) involves a two-way adaptor mounted on a scope to aspirate and irrigate the pelvicalyceal system during flexible ureteroscopy. While integrated suction single-use scopes manage small dust particles effectively, they cannot remove particles >250 µm and are limited by single use.

Objectives

To evaluate perioperative outcomes of the GLITZ system, a lightweight suction accessory for flexible ureteroscopes, facilitating laser lithotripsy with integrated aspiration.

Design

Prospective, multicenter study.

Methods

The GLITZ system, a 100 g trigger mounted on the ureteroscope handle, integrates with an irrigation and aspiration apparatus featuring a flow-regulating sensor. A finger-trigger activates suction, stopping irrigation until released, enhancing visibility and safety by automatically stopping irrigation if blockages occur. The study involved 29 patients (November 2023-April 2024). Procedures were performed using a disposable 7.5 Fr ureteroscope, ureteral access sheath, and thulium fiber or 100 W holmium:YAG laser. Surgeons evaluated ease of use and performance. Stone-free status was evaluated at a 30-day CT scan and classified as follows: Grade A: zero RF; Grade B: single RF not up 2 mm; Grade C: single RF 2.1-4 mm; and Grade D: single/multiple RFs > 4 mm. Data are reported as median and (interquartile range).

Results

A total of 31.1% of patients were female. The median age was 54 years. Pain was the most common complaint, and 41.8% had multiple stones. GLITZ system showed satisfactory performance in 93.1% of cases, with complete dust aspiration achieved in 62.1%. Device dislodgement occurred in 24.1% of cases. Median operative time was 40 min, achieving postoperative CT at 30 days confirmed Grade A stone-free status in 75.9%. Fever was the most common complication (10.3%), with no sepsis case.

Conclusion

The GLITZ system in DISS shows effectiveness with a 96.6% stone-free rate (Grade A + B) at 30 days, indicating strong potential for flexible ureteroscopy, though additional studies are needed to optimize flow rates and usability.

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.

Multicenter outcome analysis of different sheath sizes for Flexible and Navigable Suction ureteral access sheath (FANS) ureteroscopy: an EAU Endourology collaboration with the global FANS study group

Flexible and navigable suction ureteral access sheath (FANS) is a potential game changer in flexible ureteroscopy (FURS). The influence of sheath size on outcomes needs research. The primary aim was to analyze 30-day single stage stone free status (SFS), zero fragment rate (ZFR) and complications when using 10/12Fr sheaths vis a vis other sheath sizes. The global FANS research group published the 30-day outcomes in patients who underwent FANS and reasoned this can be a potential game changer. We included 295 patients from this anonymized dataset with division into two groups: Group 1 (Smaller sheath) - 10/12Fr FANS, and Group 2 (Larger sheath) - 11/13Fr or 12/14Fr sheaths. Stone volume was similar between both groups (median 1320 mm3, p = 0.88). Ureteroscopy and total operative time was longer in the smaller sheath group (35 vs. 32 min, p = 0.02 and 50 vs. 45 min, p = 0.001, respectively). While 30-day computed tomography SFS (100% stone free or single residual fragment ≤ 2 mm) were not significantly different (96% vs. 95%, p > 0.99), ZFR (100% stone-free) was better with smaller sheaths (68% vs. 53%, p = 0.02). There was no difference in postoperative complication rates, and no sepsis in both groups. Urologists should consider individualizing appropriate sheath size in normal adult kidneys. Sheath size did not affect complication rates, risk of perioperative injury to the pelvicalyceal system or ureteric injury, but smaller FANS sheaths had similar high SFS. The ZFR with smaller sheaths was better, but this needs to be validated. These smaller sheath outcomes need to be balanced with longer ureteroscopy time, operative time, reach to the lower pole, ease of suction and visibility during lithotripsy. Large volume studies in different types of pelvicalyceal anatomy can determine if indeed smaller FANS is the best choice in FURS.

The reused-disposable scope in flexible ureteroscopy for stones as a cost-conscious approach: Reporting the outcomes of a real-world practice multicenter study of 2183 patients by the team of worldwide endourological researchers group

Introduction

We aimed to assess complications and stone-free rate of flexible ureteroscopy (FU) reusing disposable scopes (RDS) after repeated sterilization.

Methods

Data from adults from 11 centers were retrospectively reviewed (January 2020-December 2022). Inclusion criteria were proximal ureteral/renal stone(s). All cases were performed using an RDS to save costs for patients who come from economically challenged environments. Residual fragments (RFs) were defined as single fragment ≥4 mm or multiple fragments of any size within 3 months. Continuous variables are presented as median and interquartile range.

Results

Two thousand one hundred and eighty-three patients were included, of whom 67.0% were male. Median age was 48.0 (36-59) years. The median stone diameter was 10.2 (9-14) mm. Flash sterilization was used in 90.2% (plasma in 60.5%). Approximately, 88% had FU with an RDS used ≤2 times (12%: 3-5 times). RDS needed to be changed intraoperatively in 3.9% of cases due to its malfunction. Commonly, defects in RDS function were reported in upward (1.6%) and downward deflection (6.5%) and image quality on white balancing (4.7%). Fever >38C was seen in 13.7% of cases, and sepsis in 0.5%. RFs were found in 31.4% of cases. Lower pole (odds ratio [OR] 5.63) or pelvis stone (OR 4.67), faulty scopes (OR 12.8), and total operation time (OR 1.05) were factors associated with higher odds of RFs. Stone size (OR 1.09), positive urine culture (OR 1.67), interpolar stone (OR 1.68), and prestenting (OR 1.37) were factors associated with higher odds of fever/sepsis.

Conclusions

RDS was used as a cost-conscious approach with a low rate of serious infections but with a high rate of RFs.

Operative outcomes 24 hours after retrograde intrarenal surgery for solitary renal calculi using a flexible and navigable suction ureteral access sheath. A prospective global multicenter study by the European Association of Urology Section on Urolithiasis

BACKGROUND

Suction techniques showed potential to improve outcomes of retrograde intra-renal surgery (RIRS). We assessed the 24-hour stone-free rate (SFR) and complications after RIRS using flexible and navigable suction ureteral access sheaths (FANS-UAS).

METHODS

Sixteen centers prospectively contributed to data (August 2023-October 2023). Inclusion criteria: age ≥18 years, single renal stone, pre and 24-hour post-RIRS CT scan. Exclusion criteria were: ureteral stone, anomalous kidney, multiple stones. SFR was divided into: 1) grade A - no fragments; 2) grade B - fragments ≤2 mm; 3) grade C - fragments 2.1-4 mm; and 4) grade D - fragments >4 mm. A multivariable logistic regression analysis model was performed to assess factors associated with the odds of having grade A stone-free status. Data are expressed as median (interquartile range), absolute numbers and frequencies, odds ratio (OR), and 95% confidence interval (CI).

RESULTS

One hundred forty-two patients with a median age of 52 years (40-61) were enrolled. 61.3% were males. Median stone volume was 1165 mm3 (656-1936). Median operative time was 48.5 (36.25-71.75) min. Transient fever (37°C-37.5°C) occurred in 10 (7%) patients. No sepsis case occurred. 96.5% of patients were stone-free (Grade A+B). Grade A SFR was 52.8%. All patients were discharged within 48 hours. Bone window (OR 3.156 95% CI 1.177-9.130, P=0.027) was the only factor significantly associated with higher odds of 100% SFR, while stone volume (OR 0.999, 95% CI 0.999-1.000, P=0.007) was significantly associated with lower odds.

CONCLUSIONS

Imaging and clinical evidence demonstrate excellent perioperative outcomes just 24 hours post RIRS with FANS-UAS. The technique demonstrates a good safety profile, ability for immediate high SFR, and a low rate of infective complications.

Rethinking Stone-free Rates and Surgical Outcomes in Endourology: A Point of View from PEARLS Members

There is a lack of consensus on definitions for the success of endourological stone treatments. The zero-fragment rate (residual fragments [RFs] <1 mm) is now considered more accurate than the stone-free rate (RFs ≤4 mm). As stone volume may be adopted as the recommended method for preoperative estimation of the stone burden, the volumetric stone-free rate may be superior to standard linear RF measurements in defining success.

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.

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.

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.