Modified Access Sheath for Continuous Flow Ureteroscopic Lithotripsy: A Preliminary Report of a Novel Concept and Technique

The role of suction devices in enhancing outcomes of retrograde intrarenal surgery: a narrative review by the YAU urolithiasis and section of EAU endourology

PURPOSE OF REVIEW

To provide a comprehensive overview of existing literature on suction-assisted ureteroscopy, evaluating its effectiveness and associated complications.

RECENT FINDINGS

A literature review was conducted in December 2024 using the MEDLINE, EMBASE and Scopus databases by two independent authors. To structure and address the clinical question, "Do suction devices improve outcomes in RIRS?", we employed the PICOS (Patient, Intervention, Comparison, Outcome, Study Type) model. Exclusion criteria included case reports, studies involving suction techniques outside the context of endocorporeal laser lithotripsy (ELL), non-English language articles and articles or clinical trials with fewer than 15 patients.

SUMMARY

Among the 36 included studies, 28 studies focused on SUAS, of which seven specifically investigated SUAS with pressure measurement, three studies examined DISS, three studies evaluated SURE and two comparative studies analyzed different suction techniques. The presented results show that advancements in suction technology seem very promising and likely to shift endourological practice.

Size matters: an in vitro evaluation of flexible vacuum-assisted ureteral access sheaths

Suction in retrograde-intrarenal surgery (RIRS) has been the focus of ongoing innovation. Expanding ranges of flexible vacuum-assisted ureteric access sheaths (FV-UAS) combined with single-use digital flexible ureteroscopes (SU-DFU) produce many potential combinations. This study aims to evaluate the efficacy of these combinations in clearing stone fragments. Three different models of flexible vacuum-assisted ureteric access sheaths were tested: Clear Petra™ (8.5/9.5Fr, 10-12Fr, 12-14Fr), YiGao™ (10-12Fr, 12-14Fr) and Innovex™ (10-12Fr, 12-14Fr). A total of 6 ratio of endoscope-to-sheath diameters (RESDs) (0.53, 0.63, 0.74, 0.79, 0.88 and 0.95) were assessed by using three different single-use digital flexible ureteroscopes (6.3Fr Hugemed™, 7.5Fr Pusen™, 9.5Fr Lithovue™). Two techniques, continuous in-scope suction and pull-out with suction were tested across 5 dust size ranges (63-125, 125-250, 250-500 µm and 0.5-1 mm, 1-2 mm). A combination resulting in a ratio of endoscope-to-sheath diameter of 0.53 offered the best range, with up to 2 mm fragments aspirated with equal success by either method. Maximal stone clearance rates at 10.2 g/min were achieved with the combination of a 7.5Fr Pusen™ with 12-14F flexible vacuum-assisted ureteric access sheath, with a ratio of endoscope-to-sheath diameter of 0.63 using continuous in-scope suction for fragments 125-250 µm. Continuous in-scope suction emerges as the dominant technique for smaller stone fragments and pull-out with suction as dominant or equivalent for greater fragment sizes. The ratio of endoscope-to-sheath diameter is not the only factor critical to improving stone-free rates. Technique should be adapted according to estimated stone fragment size.

Relocation of big stone fragments with direct-in scope suction

PURPOSE

To investigate the effectiveness of DISS feature of novel 7.5Fr and 9.2Fr single-use flexible digital ureteroscopes to relocate and evacuate stone fragments (2-5 mm in diameter) without any accessory instruments.

METHODS

An ex-vivo experimental study on porcine kidney and ureter was performed. Natural calcium oxalate dihydrate stone fragments sized 2-5 mm placed in the upper, middle and lower calyces were used. For each stone in each location 5 attempts were performed. The attempt was defined as successful if stone evacuation was reported while withdrawing the scope through the 12/14Fr UAS. The time collapsing the collecting system was also reported.

RESULTS

The time needed to collapse the porcine pelvi-calyceal system (PCS) was 4-5 s for 9.2Fr and 5-6 s for 7.5Fr scope. Evacuation of 2 mm stone fragments occurred in all trials both with 9.2Fr and 7.5Fr scopes. In case of 3 mm stone, evacuation of stone fragments was observed in 3 out of 5 and 1 out of 5 attempts in upper calyx, 5 out of 5 and 3 out of 5 in the middle calyx and 2 out of 5 and 0 out 5 in lower calyx using 7.5Fr and 9.2Fr scope, respectively.

CONCLUSION

The DISS feature of the novel 7.5Fr and 9.2Fr single-use digital flexible ureteroscope can be potentially used not only to aspirate dust but also to relocate and evacuate larger stone fragments up to 4 mm in diameter using only suction. The speed of collapse of the PCS seems to be one of the main predictors of success.

Is flexible navigable suction ureteral access sheath (FANS) safer and more efficient than conventional sheaths? Italian multicentric experience

BACKGROUND AND OBJECTIVE

The flexible and navigable suction ureteral access sheath (FANS) with continuous flow lithotripsy may improve stone-free rates (SFR) in ureterorenolithotripsy procedures, reducing operative time and the need for fragment extraction. This study aimed to compare the safety and efficacy of FANS versus conventional sheaths in patients undergoing retrograde intrarenal surgery (RIRS) for renal stones.

METHODS

From January to September 2024, patients undergoing RIRS with high-power pulsed lasers (60 W Ho:YAG or 100 W pTm:YAG) were randomized to receive either a conventional sheath (Group 1) or FANS (Group 2). Data on baseline characteristics, operative details, and complications were collected. SFR, defined as the absence of fragments > 3 mm, was assessed with non-contrast CT scans one-month post-surgery. Statistical significance was set at p < 0.05.

RESULTS

A total of 132 patients were enrolled (70 with conventional sheath, 62 with FANS). The FANS group had shorter operative times (55.25 vs. 61.36 min, p = 0.028), while laser time was similar between groups. Postoperative complications were lower in the FANS group. At one month, the FANS group had a higher SFR (95% vs. 67%, p < 0.005) and fewer re-interventions (p = 0.02).

CONCLUSIONS

FANS significantly improves SFR without increasing postoperative complications postoperative complications or negatively affecting recovery, offering a promising alternative to conventional sheaths in ureterorenolithotripsy procedures. FANS improves kidney stone surgery outcomes, providing better stone removal, fewer complications, and faster recovery compared to the standard tool.

A Global Survey to Assess Urologists' Attitudes Towards Suction Technology in Endourology by the European Association of Urology Section of Endourology and Progressive Endourological Association for Research and Leading Solutions

OBJECTIVE

To assess urologists' perceptions and current practices of using suction-based techniques and technologies in percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS) for kidney stones.

MATERIALS AND METHODS

A customized web-based 28-item questionnaire was created. All participation was voluntary. The survey was hosted on Google Forms between November 15, 2023 and November 25, 2023. Descriptive statistics were applied to demographic details and categorical responses.

RESULTS

Six hundred thirty-two responses were received. 56.5% were from Asia. Around 41.6% of respondents underwent an endourology fellowship. Personal experience of suction for PCNL was noted in 55.4% and 42.7% for RIRS. Exactly 34.9% believe that currently there is enough evidence that suction can improve stone-free rates and lower complications for both endourology surgeries. Around 55.69% believe that as evidence evolves, suction has the potential to be a game changer in endourology management of urolithiasis. Exactly 55.7% believe that the leading barrier to the adoption of suction in endourology is the lack of availability of technology. Other barriers include lack of procedural standardization (37.65%), lack of evidence (34.9%), lack of proper training (29.58%) and lack of advocation in the current guidelines (17.72%).

CONCLUSION

Our survey shows that urologists are keen to adopt suction for PCNL and RIRS but the lack of definitive evidence, standardization, equipment availability and training preclude them from using so. More high-level evidence regarding the utility of suction in endourology is required for its routine adoption in clinical practice.

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.

Comparison of tip-bendable aspiration-assisted and standard access sheaths in the treatment of lower calyceal stones

OBJECTIVE

The aim of this study was to compare the success and complication rates of retrograde intrarenal surgery for lower calyceal renal stones performed with novel tip-bendable suction ureteral access sheaths and standard ureteral access sheaths.

METHODS

Between March 2023 and March 2024, a total of 88 patients underwent retrograde intrarenal surgery for lower renal calyceal stones smaller than 20 mm. Based on the access sheath used, patients were divided into two groups: Group 1 (n=43) included patients treated with novel tip-bendable suction ureteral access sheaths and Group 2 (n=45) included patients treated with standard ureteral access sheaths. The pre- and postoperative data of the two groups were compared. Complications were assessed by using the Modified Clavine Dindo system, and stone-free rate was assessed after 4 weeks by using non-contrast computed tomography.

RESULTS

There was no significant difference between the groups regarding demographic data or preoperative laboratory results, and the median stone size was comparable in both groups. The stone-free rate did not show any significant difference between the two groups. However, the median residual stone size was substantially higher in the standard ureteral access sheaths group [4.25- (3.75-5) vs. 6- (5-7), p=0.01] and the surgical duration was less in the novel tip-bendable suction ureteral access sheaths group (p=0.032).

CONCLUSION

Our current findings demonstrate that the use of a new tip-bendable suction-assisted access sheath during retrograde intrarenal surgery in the management of lower calyceal stones less than 2 cm may shorten the operative duration, limit the rate of complications, and end up with smaller residual stone fragments when compared with the use of standard ureteral access sheath.

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.

Efficacy and intrarenal pressure analysis of flexible and navigable suction ureteral access sheaths with flexible ureteroscopy in modified surgical positions for 2-6 cm upper urinary tract stones: a multicenter retrospective study

This multicenter retrospective study aimed to assess the efficacy, intrarenal pressure (IRP), and complications of retrograde intrarenal surgery (RIRS) using a flexible and navigable suction ureteral access sheaths (FANS-UAS) in the reverse Trendelenburg lithotomy position (RTLP) for treating kidney and upper ureteral stones measuring 2-6 cm. Conducted at six medical centers in Fujian Province from 2022 to 2024, the study included 231 patients with a median stone size of 26 mm. The immediate stone-free rate (ISFR) was 90.48%, while the SFR at postoperative day 30 was 95.67%. Only two patients developed postoperative fever, two patients had ureteral laceration and most experienced mild pain. Although surgical time increased with stone size, factors such as sex, infundibulopelvic angle (IPA), and stone density had little effect on duration, and there was no significant difference between ISFR and 30-day SFR. Importantly, all IRP measurements remained within normal limits. These findings suggest that RIRS with FANS-UAS in RTLP is a safe and effective approach for managing upper urinary tract stones of 2-6 cm, especially in 2-4 cm stones.

Intelligent control of pressure based on ureteral access sheaths: renal pelvic pressure during flexible ureteroscope perfusion at different sites

OBJECTIVE

This study aimed to evaluate the accuracy and effectiveness of renal pelvic pressure (RPP) control during flexible ureteroscopic perfusion at various sites.

METHODS

Flexible ureteroscopy for the intelligent control of RPP was based on a ureteral access sheath (UAS) that integrated pressure measurement and suction functions (with automatic adjustment). Eleven consecutive patients with indurating nephrostomy tubes were enrolled. The nephrostomy tube was connected to a disposable invasive blood pressure sensor. The RPP was zeroed after the pressure stabilized. The flow rate and control value were set at 100 ml/min and - 5 mmHg, respectively. An 8.5 Fr flexible ureteroscope was irrigated at the renal pelvis, as well as the upper, middle, and lower calyces of the kidney for 1 min.

RESULTS

All 11 patients with upper urinary tract calculi underwent successful UAS placement. Pressures measured by the sheath and fistula during perfusion were - 5.07 ± 1.41 and - 4.89 ± 1.07 mmHg at the renal pelvis, -5.16 ± 1.36 and - 5.12 ± 1.32 mmHg at the upper calyces, -4.98 ± 0.87 and - 5.39 ± 1.01 mmHg at the middle calyces, as well as -4.95 ± 1.56 and - 5.64 ± 1.24 mmHg at the lower calyces, respectively. There were no significant differences in pressure between the sheath and fistula groups or in sheath and fistula pressures among parts. The RPP fluctuated; however, all values were within the safe limit of 20 mmHg.

CONCLUSION

The UAS-based pressure monitoring technology can accurately and reliably monitor and control RPP within a set range.

First clinical evaluation of a flexible digital ureteroscope with direct in scope suctioning system (Pusen DISS 7.5Ch): prospective multicentric feasibility study

PURPOSE

A new digital single-use flexible ureteroscope, Pusen direct in scope suction (DISS) 7.5Fr (PU3033AH), was evaluated with respect to manoeuvrability, suction quality, visibility and clinical efficiency.

METHODS

A prospective cohort study was conducted in six tertiary reference centers in Europe and Asia between February-April 2024. Adult patients who underwent flexible ureteroscopy and laser lithotripsy (fURSL) for urolithiasis were included. Demographic, intraoperative and follow-up characteristics were recorded. Quality parameters were rated by each surgeon using a Likert scale.

RESULTS

a total of 57 fURSL were performed. Preoperative characteristics revealed a mean stone volume of 480.00mm3 (mean Hounsfield Unit- 998). 57.9%(n = 33) of the patients were pre-stented, and a ureteric access sheath was used in 64.9%(n = 37). Integrated-suction was deemed helpful in 94.7%(n = 54) fURSL as reported by the operators. An initial stone free rate (SFR) confirmed by postoperative imaging was achieved in 84.21%(n = 48). Quality parameters of the scope reached a mean Likert score of 4.5, with a "very good" mean evaluation for "scope placement", "visual quality", "irrigation", "deflection", "manoeuvrability", and "weight". "Suction quality" and "overall performance satisfaction" were rated "good". Comparing the Pusen DISS scope with other previously used scopes, overall satisfaction was rated 4.1. When asked if the surgeons would be willing to use the Pusen DISS 7.5Fr scope in the future, all the six surgeons answered positively.

CONCLUSION

The DISS 7.5 Pusen ureteroscope displayed good visibility, manoeuvrability and suction quality, with excellent operative results. Further evaluation with larger comparative cohorts will help understand the potential of in-vivo use of integrated suctioning systems for fURSL.

The impact of siphoning effect on renal pelvis pressure during ureteroscopy using an in vitro kidney and ureter model

PURPOSE

To experimentally measure renal pelvis pressure (PRP) in an ureteroscopic model when applying a simple hydrodynamic principle, the siphoning effect.

METHODS

A 9.5Fr disposable ureteroscope was inserted into a silicone kidney-ureter model with its tip positioned at the renal pelvis. Irrigation was delivered through the ureteroscope at 100 cm above the renal pelvis. A Y-shaped adapter was fitted onto the model's renal pelvis port, accommodating a pressure sensor and a 4 Fr ureteral access catheter (UAC) through each limb. The drainage flowrate through the UAC tip was measured for 60 s each run. The distal tip of the UAC was placed at various heights below or above the center of the renal pelvis to create a siphoning effect. All trials were performed in triplicate for two lengths of 4Fr UACs: 100 cm and 70 cm (modified from 100 cm).

RESULTS

PRP was linearly dependent on the height difference from the center of the renal pelvis to the UAC tip for both tested UAC lengths. In our experimental setting, PRP can be reduced by 10 cmH20 simply by lowering the distal tip of a 4 Fr 70 cm UAC positioned alongside the ureteroscope by 19.7 cm. When using a 4 Fr 100 cm UAC, PRP can drop 10 cmH20 by lowering the distal tip of the UAC 23.3 cm below the level of the renal pelvis.

CONCLUSION

Implementing the siphoning effect for managing PRP during ureteroscopy could potentially enhance safety and effectiveness.

Ureteroscopic lithotripsy with pressure-measuring ureteral access sheath for large ureteral stones

INTRODUCTION

To evaluate the safety and efficacy of ureteroscopic lithotripsy with pressure-measuring ureteral access sheath (PM-UAS) for large ureteral stones.

MATERIAL AND METHODS

A total of 258 consecutive patients with large ureteral stones ≥15 mm was enrolled. They were treated by ureteroscopic lithotripsy with PM-UAS in the oblique supine lithotomy position. The technology can precisely monitor and automatically control cavity pressure. The cavity pressure control value was set at -15 mmHg∼-5 mmHg. The cavity pressure limit value was set at 30 mmHg. Infusion flow rate was set at 100-200 ml/min. Postoperative data such as stone-free rate and complications were analyzed.

RESULTS

PM-UAS was successfully implanted in 225 patients at one stage. Eighteen cases of patients who had failed the first surgery were successfully treated with a second operation. Fifty-one cases with stones migrating up to the kidney were converted to flexible lithotripsy. The other 15 cases were converted to percutaneous nephrolithotomy due to significant ureteral stenosis. The operative time was 49.5 ± 11.2 min. The stone-free rates after one month and three months were 87.2% (212/243) and 94.2% (229/243), respectively. Complications from grade I to II were observed in 25(10.3%) patients. No other complications from grade III to V were noted.

CONCLUSION

The ureteroscopic lithotripsy with PM-UAS is safe and efficacious for large ureteral stones.

Scoping Review of Experimental and Clinical Evidence and Its Influence on Development of the Suction Ureteral Access Sheath

The ureteral access sheath (UAS) has been a boon and a bane in flexible ureteroscopy (FURS), with its merits and demerits well established. Its design and dimensions were instrumental in reshaping the way flexible scopes were used and were key adjuncts to establishing retrograde intrarenal surgery (RIRS) as a standard of care in the endourological management of renal stones. With the ever-changing landscape of RIRS over the decades shaped by technological advancements in lasers and flexible scopes, the UAS has also continuously evolved. The utility of suction in endourology has recently changed the way RIRS is performed and is a game changer for FURS outcomes. With strong clinical and experimental evidence to support its use, the UAS has undergone a transformative change in the recent past, with its ability to monitor intrarenal pressure and provide a superior vacuum-cleaner effect that improves the trifecta of RIRS, namely an improved single-stage stone-free rate (SFR), minimise complications, and reduce reinterventions. Our comprehensive review outlines the key clinical and experimental evidence and traces the developments that were key to modifying the traditional UAS into a flexible and navigable suction ureteric access sheath (FANS) and highlights how the design and modifications, in turn, influence the ability to push the boundaries of RIRS.

Retrograde Intrarenal Surgery for Lithiasis Using Suctioning Devices: A Shift in Paradigm?

New suction endoscopes, ureteral access sheaths (UAS) and catheters aim to improve the efficacy of flexible ureteroscopy and optimize its safety. Suction UAS with non-flexible tips have shown promising results, especially in maintaining low intrarenal pressure, but also in removing small debris and reducing the "snow globe" effect. In addition, suctioning UAS with a flexible tip offers the advantage of being able to be navigated through the pyelocaliceal system to where the laser lithotripsy is performed. It can also remove small stone fragments when the flexible ureteroscope is retracted, using the Venturi effect. Direct in-scope suction (DISS) involves aspirating dust and small stone debris through the working channel of a flexible ureteroscope, thus regulating intrarenal pressure and improving visibility. Steerable aspiration catheters are other devices designed to increase stone clearance of the pyelocaliceal system. They are inserted under fluoroscopic guidance into every calyx after retraction of the flexible ureteroscope, alternating irrigation and aspiration to remove dust and small gravels. Combining flexible-tip suction UAS and the DISS technique may offer some advantages worth evaluating. The advantage of using these instruments to achieve a low intrarenal pressure was demonstrated. The true practical impact on the long-term stone-free status is a matter requiring further studies.

Prevention of complications in endourological management of stones: What are the basic measures needed before, during, and after interventions?

Objective

This narrative review aims to describe measures to minimise the risk of complications during percutaneous nephrolithotomy (PCNL), ureteroscopy, and retrograde intrarenal surgery.

Methods

A literature search was conducted from the PubMed/PMC database for papers published within the last 10 years (January 2012 to December 2022). Search terms included "ureteroscopy", "retrograde intrarenal surgery", "PCNL", "percutaneous nephrolithotomy", "complications", "sepsis", "infection", "bleed", "haemorrhage", and "hemorrhage". Key papers were identified and included meta-analyses, systematic reviews, guidelines, and primary research. The references of these papers were searched to identify any further relevant papers not included above.

Results

The evidence is assimilated with the opinions of the authors to provide recommendations. Best practice pathways for patient care in the pre-operative, intra-operative, and post-operative periods are described, including the identification and management of residual stones. Key complications (sepsis and stent issues) that are relevant for any endourological procedure are then be discussed. Operation-specific considerations are then explored. Key measures for PCNL include optimising access to minimise the chance of bleeding or visceral injury. The role of endoscopic combined intrarenal surgery in this regard is discussed. Key measures for ureteroscopy and retrograde intrarenal surgery include planning and technique to minimise the risk of ureteric injury. The role of anaesthetic assessment is discussed. The importance of specific comorbidities on each step of the pathway is highlighted as examples.

Conclusion

This review demonstrates that the principles of meticulous planning, interdisciplinary teamworking, and good operative technique can minimise the risk of complications in endourology.

Factors affecting the intraoperative calculi excretion during flexible ureteroscopy lithotripsy: an in vitro analysis

OBJECTIVE

To explore the parameters influencing intraoperative calculi excretion (ICE) during flexible ureteroscopy lithotripsy (fURL) using in vitro simulation experiments.

METHODS

3D-printed human kidney models were used to simulate the elimination of gravel during fURL. The factors influencing the ICE during fURL were analyzed by comparing the effects of different degrees of hydronephrosis (mild, moderate, and severe), surgical positions (supine and lateral position), ratios of endoscope-sheath diameter (RESD) (0.625, 0.725, and 0.825), gravel sizes (0.50-1.00 mm, 0.25-0.50 mm, and 0.10-0.25 mm), and ureteral access sheaths (UASs) (traditional UAS and negative-pressure UAS) on ICE.

RESULTS

The impacts of various UAS, RESD, degree of hydronephrosis, surgical positions, and gravel sizes on ICE were all significant (p < 0.05). We found no evidence of multicollinearity for all the independent variables, and the linear regression equation fitted as ICE ( g / min ) = 0.102 + 0.083 ∗ UAS grade - 0.050 ∗ RESD grade - 0.048 ∗ hydronephrosis grade + 0.065 ∗ position grade - 0.027 ∗ gravel size grade (R2 = 0.569).

CONCLUSION

Employing negative-pressure UAS, smaller RESD, milder hydronephrosis, lateral position, and smaller gravel size contribute to improved ICE during fURL. Among them, the adoption of negative-pressure UAS had the most substantial effects.

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.

Comparison of traditional and novel tip-flexible suctioning ureteral access sheath combined with flexible ureteroscope to treat unilateral renal calculi

OBJECTIVES

To compare the safety and efficacy of novel tip-flexible suctioning ureteral access sheath (NTFS-UAS) and traditional ureteral access sheath (T-UAS) combined with flexible ureteroscope for treating unilateral renal calculi.

MATERIALS AND METHODS

The clinical data of 214 patients with unilateral renal calculi treated by NTFS-UAS (n = 102) and T-UAS (n = 112) combined with flexible ureteroscope from August 2021 to April 2022 were analyzed retrospectively. Demographic characteristics, stone-related parameters, operative time, stone-free rates (SFR), hospitalization time and complication rate (CR) were analyzed.

RESULT

No significant difference was observed between the two groups in terms of demographic characteristics, stone-related parameters, intraoperative CR, and hospitalization time. The operative time of NTFS-UAS group was significantly shorter than T-UAS group (55.25 ± 11.42 min vs. 59.36 ± 15.59 min; P = 0.028). The NTFS-UAS group obtained significantly higher SFR on 1 day postoperatively (86.3% vs. 75.0%; P = 0.038), and higher SFR on 30 days postoperatively than T-UAS group (91.2% vs. 81.3%; P = 0.037). The hemoglobin loss of NTFS-UAS group (- 0.54 ± 0.69 g/dl) was significantly lower than T-UAS group (- 0.83 ± 0.66 g/dl; P = 0.002). There was a significantly lower incidence of overall CR (11.8% vs. 22.3%; P = 0.041), and infectious CR (8.8% vs. 18.8%; P = 0.037) in the NTFS-UAS group.

CONCLUSION

Compared to T-UAS combined with flexible ureteroscope for treating unilateral renal calculi, NTFS-UAS had superiority in higher SFR on 1 day and 30 days postoperatively. Shorter operation time, lower hemoglobin loss, lower incidences of overall and infectious CR were observed in NTFS-UAS group.

REGISTRATION NUMBER AND DATE

ChiCTR2300070210; April 5, 2023.

Omnidirectional (Flexible) Ureteral Access Sheath: Safety, Efficacy, and Initial Experience Report

Background: Recently a novel omnidirectional (OD) ureteral access sheath (UAS) has been developed. By retrospectively reviewing and comparing the flexible ureteroscopic lithotripsy (FURL) cases in our institution with either a conventional Cook UAS or an OD UAS in the past year, we shared our experience of the safety, efficacy, and relevant issues on the usage of OD UAS. Materials and Methods: The medical history and surgery details of 199 patients with kidney stones or ureterojunctional stones who underwent FURL in Xinhua Hospital, including 61 Cook UAS and 138 OD UAS, were reviewed and compared. The maximal deflection angle was measured by steering four different types of ureteroscopes to bend the OD UAS in different states. Result: The deflection angle of OD UAS was ∼110° to 130° free load, and 90° to 130° when loaded with different instruments. The stone burden and position were similar in two groups. Given a similar prestent ratio and operation time, the OD UAS group achieved a higher single-session stone-free rate (SFR) (63.9% vs 94.2%, p < 0.0001) at 1-month follow-up evaluated by a CT scan. Conclusion: OD UAS is a novel device with high safety and efficacy. The unique flexible design allows it to bend with the ureteroscope and enter renal calices and be set close to the stone. Combined with the suction port, OD UAS contributes greatly to dealing with large-burden kidney stones, shortens operation time, and improves single-session SFR.

Vacuum-assisted dedusting lithotripsy in the treatment of kidney and proximal ureteral stones less than 3 cm in size

PURPOSE

This study aimed to compare the outcomes of vacuum-assisted dedusting lithotripsy (VADL) using flexible vacuum-assisted ureteral access sheath (FV-UAS) versus traditional flexible ureteroscopic lithotripsy (fURL) in patients with kidney or proximal ureteral calculi less than 3 cm in size.

METHODS

A total of 371 patients who successfully underwent fURL treatment were enrolled. These patients were divided into traditional fURL group and VADL group. Outcomes of both groups were compared using 1:1 propensity score-matched analysis. Stratified analyses based on stone size and location were also conducted.

RESULTS

Finally, 103 well-matched patients in each group were identified. No septic shock or death occurred. The immediate stone-free rate (SFR) and follow-up SFR of VADL group were significantly higher (78.6% vs. 50.5%, p < 0.001; 94.2%% vs. 75.7%, p < 0.001). No difference was observed in postoperative fever rate (2.9% vs. 3.9%, p = 1.000) and duration of lithotripsy (37.7 ± 20.1 min vs. 40.3 ± 18.9 min, p = 0.235). For patients with stones ≤ 2 cm in size, the immediate SFR and follow-up SFR in VADL group were higher (86.7% vs. 60.6%, p < 0.001; 96.0% vs. 83.1%, p = 0.010). The same trend was observed in the 2-3 cm subgroup (57.1% vs. 28.1%, p = 0.023; 89.3% vs. 59.4%, p = 0.009). Although the in situ fragmentation strategy was employed more frequently in VADL group for lower pole stones, the SFR was still higher. Subgroup analyses did not reveal any significant differences in either infectious complications or duration of lithotripsy.

CONCLUSION

VADL technique can significantly improve the postoperative SFR for the patients with kidney or proximal ureteral stones less than 3 cm in size treated by flexible ureteroscope.

Application of tip-bendable ureteral access sheath in flexible ureteroscopic lithotripsy: an initial experience of 224 cases

INTRODUCTION

During the last decades, the advent of flexible ureteroscopic lithotripsy has revolutionized the management of upper urinary tract stones. We designed a patented tip-bendable ureteral access sheath to facilitate stone clearance. Our current study reported our initial experience of 224 cases.

MATERIALS AND METHODS

The study is a descriptive, retrospective analysis. The initial 224 cases, operated consecutively by one surgeon during 16 months, were reviewed. The novel tip-bendable ureteral access sheath was applied in the procedure. Demographics, laboratory tests, and peri- and postoperative findings (operation duration, stone-free rate (SFR), utilization of flexible instruments and complications) were analyzed.

RESUTLS

The median age of the patients was 56 years and the mean stones size was 2.3 ± 1.3 cm. There were 63 cases of upper ureteral stone, 93cases of renal stone and 68 cases of ureteral-renal stones. The mean operative time was 69.2 ± 65.2 min. The immediate stone-free rate was 76.8% and the 1 month post-operative stone-free rate was 97.3%. Most cases(95.5%)were success in single session. Two patient experienced post-operative fever. There was no unplanned readmission. The frequency of post-operative complications was estimated at 0.89% (Clavien I).

CONCLUSION

Flexible ureteroscopic lithotripsy with tip-bendable ureteral access sheath is a safe and effective procedure, which can achieve excellent stone clearance.

Flexible ureteroscopic lithotripsy with a suctioning ureteral access sheath for removing upper urinary calculi under local anesthesia

Objectives

We aimed to probe the safety and effectiveness of flexible ureteroscopic lithotripsy (FURL) with a suctioning ureteral access sheath (S-UAS) for removing upper urinary calculi under local anesthesia (LA).

Materials and methods

The clinical data of 56 patients with upper urinary calculi treated by FURL with an S-UAS under LA during the period between September 2019 and November 2022 were analyzed retrospectively. For LA, intramuscular pethidine (1.0-2.0 mg/kg) and phenergan (25 mg) were administered 30 min prior to surgery, and oxybuprocaine hydrochloride gel was administered through the urethra at the start of the surgery. The S-UAS and flexible ureteroscope were used for FURL. Demographic characteristics, stone-related parameters, and clinical outcomes were analyzed.

Result

A total of 66 procedures were performed successfully on 46 patients (Group A), who underwent unilateral surgeries, and on 10 patients (Group B) who underwent same-session bilateral surgeries. All 56 patients were operated upon without altering the anesthesia strategy, and none required additional analgesia. The mean stone sizes of the Group A and Group B patients were 20.24 ± 5.45 mm and 29.40 ± 3.89 mm, respectively. The mean operative times of the two groups were 53.04 ± 13.35 min and 90.00 ± 15.81 min, respectively. In Group A, the stone-free rates (SFRs) were 76.1% (35/46) and 85.1% (40/46) at postoperative day 1 and day 30, respectively. In Group B, the SFRs were 80.0% (16/20) and 85.0% (17/20), respectively. Four (8.7%) patients in Group A suffered complications such as fever, stent pain, urosepsis, and steinstrasse. In Group B, one (10%) patient suffered from fever.

Conclusion

FURL, combined with an S-UAS under LA, is a feasible option and provides satisfactory clinical outcomes for appropriately selected patients.

Using vacuum-assisted ureteral access sheath in the treatment of complex steinstrasse

Steinstrasse is an iatrogenic condition resulting from upper urinary tract lithotripsy. Uncomplicated steinstrasse can be managed expectantly. Complex steinstrasse can pose a therapeutic challenge. The vacuum-assisted ureteral access sheath (vaUAS) is similar to a conventional ureteral access sheath but has a side branch that can be connected to vacuum apparatus. This device seemed to be useful in the management of complex steinstrasse. 35 patients with complex steinstrasse, defined as steinstrasse containing ≥ 4 stones or with an aggregate length of ≥ 1.5 cm, were treated in four tertiary medical centers using the vaUAS in this prospective and non-randomized study. The vaUAS was inserted into the ureter over a guidewire until the tip of the vaUAS was in contact with the lowermost stone fragment. A 7 Fr./8.4 Fr. semirigid ureteroscope and a holmium laser were used to pulverize the obstructing stone. All the stone fragments were aspirated either in the space between the scope and the sheath, or through the channel of the sheath by withdrawing the scope to the proximal of the aspiration port. All patients were steinstrasse-free at end of the procedure, as assessed visually and by KUB. At the 3-month follow-up, 94.3% of patients were stone-free with or without a supplementary procedure. There were no perioperative complications. Five patients experienced postoperative fever and/or significant hematuria, and one patient had transient sepsis, a grade I and IV Clavien complication, respectively. vaUAS can be an effective adjunctive device in the management of complex steinstrasse.

Optimizing Outcomes in Flexible Ureteroscopy: A Narrative Review of Suction Techniques

OBJECTIVE

The aim of this review is to summarize the existing suction systems in flexible ureteroscopy (fURS) and to evaluate their effectiveness and safety.

METHODS

A narrative review was performed using the Pubmed and Web of Science Core Collection (WoSCC) databases. Additionally, we conducted a search on the Twitter platform. Studies including suctions systems in fURS were included. Editorials, letters and studies reporting intervention with semirigid ureteroscopy, PCNL and mPCNL were excluded.

RESULTS

A total of 12 studies were included in this review. These studies comprised one in vitro study, one ex vivo study, one experimental study and eight cohort studies. The Pubmed and WoSCC searches identified three suction techniques (Irrigation/Suctioning system with control of pressure, suction ureteral access sheath (sUAS) and direct in scope suction (DISS)), and the Twitter search identified four of them. The overall results showed that suction is an effective and safe technique that improves stone-free rates, reduces operative time and limits complication rates after fURS.

CONCLUSIONS

The use of suctioning during common endourological procedures has been shown to improve safety and efficacy in several indications. However, randomized controlled trials are needed to confirm this.

Clinical application of flexible ureteroscopic sheath with controllable intraluminal pressure in treating ureteral stones

Objective

The purpose of the study was to assess the clinical efficacy and safety of a combined perfusion suction platform with pressure feedback control function and an ureteroscopic suction sheath that can measure the ureteropelvic pressure in implementing lithotripsies.

Methods

Fifty-two patients who underwent lithotripsy under intelligent monitoring of ureteral intraluminal pressure from June 2016 to January 2018 were retrospectively recruited. The inclusion standard was stone diameter >1.5 cm but <2.5 cm. After the 12/14 Fr suction sheath was placed, manometer interface and suction interface of the sheath were connected to the platform via the pressure sensor and suction tube, respectively. The ureteroscope was connected to the platform perfusion pump, and the crushed stones were aspirated out under negative pressure.

Results

According to the location of the stone, 21 (40.4%) cases were classified as upper ureteral stones, 19 (36.5%) were midureteral stones, and 12 (23.1%) were lower ureteral stones. Forty-seven patients underwent successful primary sheath placement and lithotripsy with a mean operative time of 34.5 (standard deviation 18.3) min. Retrograde stone migration did not occur. There were eight patients with hematuria postoperatively. Serious complication was 1.9% with one case of ureteral perforation. Stone clearance was 95.7% at Day 1-2 postoperatively, and 100% at Day 30 postoperatively.

Conclusion

Ureteroscopic lithotripsy with intelligent pressure control using our device improved the efficiency of the lithotripsy and rate of stone clearance. The safety of the operation can be ensured. It is worth popularization and application in clinical practice.

What is the appropriate gravel size during ureteroscopy lithotripsy? An in vitro evaluation

To propose the suitable diameter of calculus debris produced during flexible ureteroscopy lithotripsy (fURL). A glass tube was used to simulate the stone excretion process during Furl. Different stone diameters (0.50-1.00 mm, 0.25-0.50 mm, and 0.10-0.25 mm) with three sizes of flexible ureteroscopy (fURS) (7.5Fr, 8.7Fr, and 9.9Fr) and ureteral access sheath (UAS) (12/14Fr) with or without negative pressure suction were employed in the experiment. The intraoperative calculi excretion (ICE) was recorded according to the stones discharged from the gap between fURS and UAS. The ICE raised significantly in thinner fURS and UAS due to the smaller Ratio of Endoscope-Sheath Diameter (RESD). The gravel size ≤ 0.25 mm was conducive to drainage with traditional UAS, while using fURS with negative-pressure UAS could significantly improve ICE. The gravel size ≤ 0.5 mm was conducive to expulsion. We clarify that ICE during ureteroscopy relates to RESD and negative pressure suction. The proper size of the stone fragment is critical in ensuring the expulsion during fURL, ≤ 0.25 mm in traditional UAS and ≤ 0.50 mm in negative-pressure UAS, respectively.

International Alliance of Urolithiasis guideline on retrograde intrarenal surgery

OBJECTIVES

To set out the second in a series of guidelines on the treatment of urolithiasis by the International Alliance of Urolithiasis that concerns retrograde intrarenal surgery (RIRS), with the aim of providing a clinical framework for urologists performing RIRS.

MATERIALS AND METHODS

After a comprehensive search of RIRS-related literature published between 1 January 1964 and 1 October 2021 from the PubMed database, systematic review and assessment were performed to inform a series of recommendations, which were graded using modified GRADE methodology. Additionally, quality of evidence was classified using a modification of the Oxford Centre for Evidence-Based Medicine Levels of Evidence system. Finally, related comments were provided.

RESULTS

A total of 36 recommendations were developed and graded that covered the following topics: indications and contraindications; preoperative imaging; preoperative ureteric stenting; preoperative medications; peri-operative antibiotics; management of antithrombotic therapy; anaesthesia; patient positioning; equipment; lithotripsy; exit strategy; and complications.

CONCLUSION

The series of recommendations regarding RIRS, along with the related commentary and supporting documentation, offered here should help provide safe and effective performance of RIRS.

Single-use versus conventional reusable flexible ureteroscopes - an evaluation of the functional parameters

The purpose of single-use flexible ureteroscopes (su-fURS) was to overcome the limitations of conventional reusable ureteroscopes in terms of maneuverability and maintenance. We aimed to perform a systematic literature review on available su-fURS performance versus conventional reusable fURS focusing on clinical data. A systematic research using Pubmed was performed evaluating single-use fURS and reusable fURS in urinary tract stone disease, including prospective assessments and case series. This review aimed to provide an overview of single-use and disposable flexible ureteroscopes and to examine and compare their capabilities (deflection, irrigation, optical properties). We included 11 studies, where the single-use fURS were compared to the reusable fURS. The studies with single-use ureteroscopes included data on LithoVue (Boston Scientific), The Uscope UE3022 (Pusen, Zhuhai, China), NeoFlex-Flexible, (Neoscope Inc San Jose, CA), 23 YC-FR-A (Shaogang). For reusable ureteroscopes, data were included on three models, two digital (Karl Storz Flex-XC and Olympus URF-Vo) and one fiber optic (Wolf-Cobra). There were no significant differences in stone-free rate, procedure duration, or functional capabilities between single-use fURS and reusable fURS. The systematic literature review analyzed operative time, functional capabilities, stone-free rates, and postoperative complications of the ureteroscopes, and a special chapter about renal abnormalities to emphasize that they are a good choice having a high proportion of stone-free rates and few risks, particularly in treating difficult-to-access calculi. Single-use fURS demonstrate a comparable efficacy with reusable fURS in resolving renal lithiasis. Further studies on clinical efficacy are needed to determine whether single-use fURS will reliably replace its reusable counterpart.

Comparison of retrograde intrarenal stone surgery with and without a ureteral access sheath using kidney injury molecule-1 (KIM-1) levels: a prospective randomized study

The objective is to compare patients who underwent retrograde intrarenal surgery with and without a ureteral access sheath (UAS) using kidney injury molecule-1 (KIM-1) levels. We also examined the difference in kidney damage between standard and dual lumen UAS. Sixty patients diagnosed with kidney stones and scheduled for RIRS were randomized into three groups: RIRS without UAS (Group 1), 11Fr/13Fr Boston scientific Navigator™ UAS (Group 2), and 11Fr/13Fr dual lumen ClearPetra™ UAS (Group 3). Data were prospectively collected in consecutive patients. Urine KIM-1/Cr levels were measured preoperatively, at postoperative 4 h, and on a postoperative day 14. Stone size, location, number, pre- and postoperative stent use, operation time, stone-free rate (SFR), post-ureteroscopic lesion scale (PULS) grade, hospitalization duration, and complications were recorded. There was no significant difference in demographical parameters and preoperative KIM-1/Cr levels among the groups. Postoperative 4th-hour urine KIM-1/Cr levels were higher in patients without UAS than patients with UAS (1.86, 0.67, 0.63 Groups 1, 2, 3, respectively). In comparing group 1 with groups 2 and 3 separately, Group 1 had a statistically significantly higher value than both groups (p = 0.002, p = 0.001, respectively). According to UAS type, there was no significant difference between groups 2 and 3. The use of UAS during RIRS has been shown to reduce kidney injury in the evaluation with KIM-1. Different UAS types on kidney injury and which one can protect the kidneys more during the procedure; will be elucidated by prospective randomized studies involving larger patient groups and UAS types.

Ureteral Access Sheaths and Its Use in the Future: A Comprehensive Update Based on a Literature Review

Ureteral access sheaths (UASs) are part of urologist’s armamentarium when performing retrograde intrarenal surgery (RIRS). Recently, the world of RIRS has changed dramatically with the development of three game-changers: thulium fiber laser (TFL), smaller size single use digital flexible ureterosopes and intraoperative intrarenal pressure (IRP) measurement devices. We aimed to clarify the impact of UASs on IRP, complications and SFRs and put its indications in perspective of these three major technological improvements. A systematic review of the literature using the Medline, Scopus and Web of Science databases was performed by two authors and relevant studies were selected according to PRISMA guidelines. Recent studies showed that using a UAS lowers IRP and intrarenal temperature by increasing irrigation outflow during RIRS. Data on the impact of a UAS on SFRs, postoperative pain, risk of infectious complications, risk of ureteral strictures and risk of bladder recurrence of urothelial carcinoma after diagnostic RIRS were inconclusive. Prestenting for at least one week resulted in ureteral enlargement, while the influence of pre-operative administration of alpha-blockers was unclear. Since TFL, smaller single use digital ureteroscopes and devices with integrated pressure-measuring and aspiration technology seemed to increase SFRs and decrease pressure and temperature related complications, indications on the use of a UAS may decrease in the near future.

Comparison of retrograde intrarenal stone surgery with and without a ureteral access sheath using kidney injury molecule-1 (KIM-1) levels: a prospective randomized study

The objective is to compare patients who underwent retrograde intrarenal surgery with and without a ureteral access sheath (UAS) using kidney injury molecule-1 (KIM-1) levels. We also examined the difference in kidney damage between standard and dual lumen UAS. Sixty patients diagnosed with kidney stones and scheduled for RIRS were randomized into three groups: RIRS without UAS (Group 1), 11Fr/13Fr Boston scientific Navigator™ UAS (Group 2), and 11Fr/13Fr dual lumen ClearPetra™ UAS (Group 3). Data were prospectively collected in consecutive patients. Urine KIM-1/Cr levels were measured preoperatively, at postoperative 4 h, and on a postoperative day 14. Stone size, location, number, pre- and postoperative stent use, operation time, stone-free rate (SFR), post-ureteroscopic lesion scale (PULS) grade, hospitalization duration, and complications were recorded. There was no significant difference in demographical parameters and preoperative KIM-1/Cr levels among the groups. Postoperative 4th-hour urine KIM-1/Cr levels were higher in patients without UAS than patients with UAS (1.86, 0.67, 0.63 Groups 1, 2, 3, respectively). In comparing group 1 with groups 2 and 3 separately, Group 1 had a statistically significantly higher value than both groups (p = 0.002, p = 0.001, respectively). According to UAS type, there was no significant difference between groups 2 and 3. The use of UAS during RIRS has been shown to reduce kidney injury in the evaluation with KIM-1. Different UAS types on kidney injury and which one can protect the kidneys more during the procedure; will be elucidated by prospective randomized studies involving larger patient groups and UAS types.

Novel flexible vacuum-assisted ureteral access sheath(FV-UAS) can actively control intrarenal pressure and obtain a complete stone-free status

OBJECTIVES

To compare the safety and effectiveness of a novel flexible vacuum-assisted ureteral access sheath (FV-UAS) and traditional ureteral access sheath (UAS) in simulating retrograde intrarenal surgery (RIRS).

MATERIALS AND METHODS

Amanometric model was established in porcine kidneys to observe the change inintrarenal pressure in the FV-UAS and traditional UAS groups at different irrigation fluid velocities of 30 ml/min, 50 ml/min, 80 ml/min, and 100 ml/min. Establish a kidney stone model (with 0.2 g, dry, ≤ 5 mm stones) to simulate RIRS. A total of 20 porcine kidneys wererandomly numbered from 1 to 20 (FV-UAS group, 1-10; traditional UAS group, 11-20). The stone volume clearance rate and operation time were compared between the two groups. [" Stone volume clearance rate= (1-(residual stone volume)/(preoperative stone volume))×100%" )]. Stones volume was obtained by computed tomography (CT) preoperatively and postoperatively.

RESULTS

FV-UAS can follow flexible ureteroscopy (f-URS) to cross the ureteropelvic junction (UPJ) and into the renal pelvis and calyces. FV-UAS can actively make intrarenal pressure (IRP) less than 10 cmH2O by adjusting the negative values atdifferent irrigation fluid velocities. The mean residual stone volume of the FV-UAS vs. traditional UAS groups was33.7 mm3 vs. 92.5 mm3 (P = 0.017). The mean stone volume clearance rates of the FV-UAS vs. traditional UAS groups were 98.5 % and95.9 %, respectively (P = 0.017). Seven cases achieved complete stone-free status in the FV-UAS group. All patients hadresidual fragments postoperatively in the traditional UAS group.

CONCLUSIONS

FV-UAS can follow f-URS to cross the UPJ and into the renal pelvis and calyces, avoiding the interference of UPJ in controlling IRP. FV-UAS can actively control the IRP to be reduced to the desired range by adjusting the negative value under any irrigation fluid velocity. FV-UAS close to the stone can achieve complete stone-free in RIRS.

The use of 14/16Fr ureter access sheath for safe and effective management of large upper ureteral calculi

OBJECTIVE

To evaluate the effectiveness of ureteroscopic lithotripsy for the management of large proximal ureteral stones > 10 mm using 14/16 Fr ureteral access sheath (UAS).

MATERIALS AND METHODS

Patients' data from prospective database undergoing ureteroscopic laser lithotripsy with a use of 14/16Fr UAS were collected. All patients were pre-stented prior to the procedure. The fragmentation was performed with a semi-rigid ureteroscope using holmium laser energy with a power setting of 35 W (frequency-35 Hz; energy-1 J). Follow-up was scheduled at 4 weeks and 3 months postoperatively.

RESULTS

In total 78 patients, 43 males and 35 females, were included in the study. The mean age of the patients was 59.5 ± 13.3 with a mean maximal stone diameter of 13.4 ± 2.1. The mean operative time was 35.7 ± 9.7 and the mean hospital stay was 2 ± 0.7 days. The primary SFR at 4 weeks was 73 patients (93.6%), while all 78 patients (100%) were stone free at 3-month follow-up, 2 of the patients receiving additional treatment. In total, 8 (10.2%) patients experienced Grade II complications. Intraoperative ureteral lesions were observed in 41 (52.6%) cases. Out of them 31 patients (39.7%) developed Grade 1, 8 patients (10.3%) Grade 2 and only 3 patients (2.6%) Grade 3 lesions.

CONCLUSION

The use of 14/16Fr ureteral access sheath on pre-stented patients was associated with successful outcomes. A high stone-free rate of 93.6% was achieved at 4-week follow-up. The procedure was not associated with increased rate of postoperative complications and intraoperative ureteral injury.

The Life and Death of Percutaneous Stone Removal: "Looking Back-Looking Forward"

Although percutaneous nephrolithotomy (PCNL) is less morbid than open surgery, it still carries risks of significant complications as well as injury to the renal parenchyma. Flexible ureteroscopic stone removal, although causes no appreciable damage to the renal parenchyma, has limitations, most notably, a lower stone-free rate than PCNL. Advances in our knowledge regarding ureteral physiology combined with technical developments applied to ureteral access sheath deployment and size may well propel retrograde intrarenal surgery to the forefront of kidney stone removal, regardless of stone size or location.

Comparison of the Efficacy of ShuoTong Ureteroscopy and Simple Flexible Ureteroscopy in the Treatment of Unilateral Upper Ureteral Calculi

Background: ShuoTong ureteroscopy (Sotn-ureteroscopy, ST-URS), a new lithotripsy operation method developed on the basis of ureteroscopy, is widely used to treat ureteral stones in China. Its composition includes rigid ureteral access sheath, standard mirror, lithotripsy mirror, and ShuoTong perfusion aspirator (ST-APM). Here, we compared the efficacy and safety of the ST-URS and the flexible ureteroscope (F-URS) holmium laser lithotripsy in the treatment of unilateral upper ureteral calculi. Methods: Retrospective analysis was conducted on the clinical data of 280 patients who met the inclusion 1) urinary tract CT was diagnosed with unilateral single upper ureteral calculi above the L4 lumbar spine; 2) patient age was from 18 to 80 years old; 3) patients were informed and consented to this study; and 4) patients were approved by the hospital ethics committee (proof number: KY-2019-020) and the exclusion criteria for unilateral upper ureteral calculi in the First Affiliated Hospital of Xiamen University from January 2018 to November 2020, and they were divided into the ST-URS group and the flexible ureteroscopy (F-URS) group. Results: The stone-free rate of 1 day after operation of the ST-URS group was significantly higher than the F-URS group (63.71 vs. 34.62%, P < 0.0001). The operative time (38.45 vs. 46.18 min, P = 0.005) and hospitalization cost (27,203 vs. 33,220 Yuan, P < 0.0001) of the ST-URS group were significantly lower than the F-URS group. There were no significant differences in the success rate of ureteral access sheath placement, operative blood loss, stone-free rate of 1 month after operation, postoperative complications, postoperative hospital stay, and postoperative visual analog scale (VAS) pain score between the two groups (P > 0.05). In subgroups of a diameter of calculi ≥ 1.5 cm, calculi CT numerical value ≥ 1,000 Hounsfield unit and the preoperative hydronephrosis range ≥ 3.0 cm, ST-URS shows more advantages in the operative time, stone-free rate of 1 day after the operation, the hospitalization cost, and the incidence of postoperative complications. Conclusion: In unilateral upper ureteral stones treated with a holmium laser, compared with the simple F-URS, the ST-URS has a shorter operative time, lower hospitalization cost, and a higher stone-free rate of 1 day after the operation, suggesting that the ST-URS could be more widely applied in clinics.

Suction Use During Endourological Procedures

PURPOSE OF REVIEW

Equipment used in endourology is constantly evolving due to increasing incidence of urolithiasis. Suctioning has been used mainly in PCNL in conjunction with ultrasonic and ballistic devices for stone removal. Recently technological advances permitted the use of suctioning in more endourological techniques. This review aims to summarize the literature regarding these advancements and analyze the upcoming results.

RECENT FINDINGS

Several centers have conducted experimental and clinical studies on suctioning use during PCNL, mPCNL, and ureteroscopy and concluded that it is an effective and safe adjustment that improves stone-free rates and limits complication rates after these procedures. Suctioning use during common endourological procedures led to improved safety and efficacy among several indications. Due to the observational nature and small sample size of many studies, larger RCTs are needed to make safe conclusions.

Use of a modified ureteral access sheath in semi-rigid ureteroscopy to treat large upper ureteral stones is associated with high stone free rates

Objective

To examine differences in outcomes of semi-rigid ureteroscopy (URS) with or without a modified-ureteral-access-sheath (mUAS) to treat large upper ureteral stones.

Methods

Patients with single, radio-opaque large upper ureteral stone (≥10 mm) treated using semi-rigid URS between August 2013 and October 2016 were retrospectively evaluated. The stone-free status was determined from Kidney-ureter-bladder (KUB) X-ray films taken on postoperative Day 1 and after 1 month.

Results

Of 103 patients meeting inclusion criteria, 43 (41.75%) and 60 (58.25%) were treated with semi-rigid URS with and without mUAS, respectively. The immediate stone-free rate (SFR) for the mUAS group was significantly higher than the non-mUAS group (40 [93.0%] vs. 46 [76.7%]; p = 0.033). The SFR at 1 month was also high for patients treated using mUAS, but not statistically different from patients not treated with mUAS (41 [95.3%] mUAS vs. 51 [85.0%] non-mUAS; p = 0.115). Auxiliary procedure rates were significantly lower for mUAS patients compared to non-mUAS patients (2 [4.7%] vs. 14 [23.3%]; p = 0.01). There were no significant differences in surgical duration and hospital stays, and the overall complication rates were statistically similar for mUAS patients compared to non-mUAS patients (1 [2.3%] vs. 3 [5.0%]; p = 0.638).

Conclusion

Application of mUAS to treat large upper ureteric stones was associated with higher immediate SFR and final SFR, and lower auxiliary procedure rates relative to patients treated without use of mUAS. Moreover, the use of mUAS did not lengthen operation duration or hospital stays.

Updates in endourological management of urolithiasis

Urinary stone disease, or urolithiasis, is a very common disease with increasing prevalence and incidence. With the advancement of endoscopic techniques, the treatment outcomes of ureteroscopy (or transureteral lithotripsy) and percutaneous nephrolithotomy are continuously improving. In recent years, there have been many new developments in the field, including new endoscopy design, more effective auxiliary tools, improvement in treatment protocols, introduction of robotic technology, combining both ureteroscopy and percutaneous nephrolithotomy (endoscopic combined intrarenal surgery or transureteral lithotripsy-assisted percutaneous nephrolithotomy), improvement in laser technology, and so on. All these new inputs will further improve the treatment efficacy and safety of the procedures, thus benefiting our patients. In the present review, we briefly go through the main steps of ureteroscopy and percutaneous nephrolithotomy, with a concise description and application of these new advances.

Comparison of suctioning and traditional ureteral access sheath during flexible ureteroscopy in the treatment of renal stones

PURPOSE

To compare the efficiency and safety of suctioning ureteral access sheath (UAS) and traditional UAS during flexible ureteroscopy (FURS) for treatment of renal stones.

METHODS

Between January 2015 and December 2017, 165 patients who had renal stones successfully underwent FURS with suctioning UAS created by connecting a channel on the tail of the suctioning UAS to a vacuum device. The outcomes of these patients were compared with those of 165 patients undergoing FURS with traditional UAS using a 1:1 scenario matched-pair analysis. The matching parameters were age, gender and stone burden.

RESULTS

The baseline characteristics were homogeneous between the two groups. The suctioning UAS group had significantly higher SFR one day postoperatively (82.4% vs. 71.5%; P = 0.02), but SFR 1 month postoperatively was comparable in the two groups (P = 0.13). The incidence of overall complications was significantly higher in the traditional UAS group (24.8% vs 11.5%; P < 0.001). Regarding individual complications, the traditional UAS group was associated with a significantly higher incidence of fever (13.9% vs 5.5%; P = 0.009) and urosepsis requiring only additional antibiotics (6.7% vs 1.8%; P = 0.029). No significant difference was noted in the incidence of septic shock, hematuria, steinstrasse or ureteral stricture. The suctioning UAS group had significantly shorter operative time (49.7 + 16.3 min vs. 57.0 ± 14.0 min; P < 0.001).

CONCLUSIONS

Compared to traditional UAS during FURS for treating renal stones, suctioning UAS had the advantages of higher SFR 1 day postoperatively, a lower incidence of infectious complications and a shorter operative time. Further well-designed studies are required to confirm the results.

Systematic review of ureteral access sheaths: facts and myths

The aim of the present paper was to review the literature on all available ureteral access sheaths (UASs) with their indications, limitations, risks, advantages and disadvantages in current modern endourological practice. Two authors searched Medline, Scopus, Embase and Web of Science databases to identify studies on UASs published in English. No time period restriction was applied. All original articles reporting outcomes or innovations were included. Additional articles identified through references lists were also included. Case reports, editorials, letters, review articles and meeting abstracts were excluded. A total of 754 abstracts were screened, 176 original articles were assessed for eligibility and 83 articles were included in the review. Based on a low level of evidence, UASs increase irrigation flow during flexible ureteroscopy and decrease intrapelvic pressure and probably infectious complications. Data were controversial and sparse on the impact of UASs on multiple reinsertions and withdrawals of a ureteroscope, stone-free rates, ureteroscope protection or damage, postoperative pain, risk of ureteral strictures, and also on its cost-effectiveness. Studies on the benefit of UASs in paediatrics and in patients with a coagulopathy were inconclusive. In the absence of good randomized data, the true impact of UASs on surgery outcome remains unclear. The present review may contribute to the evidence-based decision-making process at the individual patient level regarding whether or not a UAS should be used.