Retrograde intrarenal surgery: Past, present, and future

Intrarenal Pressure in Retrograde Intrarenal Surgery: A Narrative Review

OBJECTIVE

To review the latest evidence on the complications of elevated intrarenal pressures (IRPs) in retrograde intrarenal surgery (RIRS) and the strategies to mitigate the increase of IRP during surgery.

METHODS

A comprehensive literature search of PubMed, Web of Science and EBSCO research databases was conducted from inception to July 31, 2024. The analysis involved a narrative review.

RESULTS

Normal physiological IRP in an unobstructed kidney ranges from 0 to 15 mmHg (0-20 cmH2O). During RIRS, dangerous IRPs are often reached, resulting in complications. These include pyelorenal reflux, which predisposes the patient to fever, urosepsis and postoperative pain, and forniceal rupture, which may result in intraoperative bleeding as well as acute kidney injury, postoperative pain, and fluid overload. To maintain safe IRP, outflow should be as close as possible to inflow. Minimizing the irrigation pressure by controlling the flow rate, reducing the pressure of the irrigant fluid, using a ureteral access sheath and maintaining an empty bladder during the procedure and, more recently, using real-time IRP monitoring are appropriate techniques to mitigate unsafe IRPs.

CONCLUSION

Several complications of RIRS are related to elevated IRPs, which cause pyelorenal backflow and forniceal rupture. Irrigation flow and pressure dynamics drive IRP changes during RIRS. Awareness of these factors will allow urologists to institute strategies to mitigate IRP during RIRS, thereby reducing complications and improving patient outcomes.

Efficacy analysis of tip-flexible suction access sheath during flexible ureteroscopic lithotripsy for unilateral upper urinary tract calculi

PURPOSE

This study aims to evaluate the efficacy of tip-flexible suctioning ureteral access sheath (TFS-UAS) compared to traditional ureteral access sheath (T-UAS) in flexible ureteroscopic lithotripsy (FURL) for unilateral upper urinary tract calculi.

METHODS

The study retrospectively compared outcomes from 103 cases using TFS-UAS and 138 using T-UAS treated with FURL for unilateral upper urinary tract calculi from January to October 2023. Assessed parameters included patient demographics, stone characteristics, preoperative urine cultures, ureteral pre-stenting, comorbidities, procedure time, stone-free rate (SFR), utilization of stone retrieval baskets, and postoperative Systemic Inflammatory Response Syndrome (SIRS) rates. The maximum angle of deflection was also measured when the flexible ureteroscope was located in different parts of the TFS-UAS with different diameters in vitro.

RESULTS

The TFS-UAS group achieved a higher Immediate SFR (76.70% vs. 63.77%, p = 0.031) and final SFR (89.32% vs. 73.91%, p = 0.003) than the T-UAS group, especially in the lower calyx stones (80.00% vs. 41.18%, p = 0.018) and upper urinary tract calculi with a cumulative diameter of 2 cm or larger (68.97% vs. 42.11%, p = 0.029). Notably, TFS-UAS with a 10 French (F) inside diameter size achieved a higher SFR (88.57% vs. 70.59%, p = 0.041) and a greater deflection angle than the 12.5 F inside diameter size. No significant variations were observed in the operative duration, hospitalization duration and the occurrence of SIRS between the compared cohorts.

CONCLUSION

TFS-UAS significantly improves SFR in FURL treatment of unilateral upper urinary tract calculi, particularly for stones located in the lower calyx or with a cumulative diameter of 2 cm or greater, compared to T-UAS.

Does tilt-retrograde intrarenal surgery enhance stone clearance and offer better surgical ergonomics in patients with renal calculi? A prospective randomized control study

Introduction

Retrograde intrarenal surgery (RIRS) is the standard treatment for renal calculi. Direct visualization and fragmentation are its major advantages. The variable stone clearance rates and the ergonomic challenges faced by urologists are a few limitations. Table tilt enhances stone clearance and improves surgical ergonomics by facilitating better access to stones and reducing procedural strain.

Subjects and Methods

In this prospective study, patients with intrarenal calculi were randomized into standard lithotomy RIRS (S-RIRS) and table-tilted RIRS (T-RIRS) groups. Specified table tilts were suggested for each of the stone locations. The outcomes with regard to stone clearance, operative and lasing time, and ergonomics were studied.

Results

About 100 patients were studied, with 50 in each group. The overall operating time and lasing time in the T-RIRS group were less than that in the S-RIRS group (P < 0.001). The complication rates were the same in both groups. Most surgeons felt that the surgical ergonomics was better in the T-RIRS group (P < 0.001). When stone-free status was analyzed, seven patients in the S-RIRS group and one in the T-RIRS group had residual stones. The mean Borg category-ratio 10 (CR-10) scores in the S-RIRS and T-RIRS groups were 4.18 and 2.20, respectively (P < 0.001).

Conclusions

This is the first study to document the distinct advantages of T-RIRS and its benefits on surgical ergonomics. T-RIRS resulted in significantly shorter operative and lasing times, particularly for stones in lower calyces. Surgical ergonomics, assessed by the Borg CR-10 scale, were significantly better in the T-RIRS group. T-RIRS should become a standard of care for patients undergoing RIRS.

The application of intravenous general anesthesia under nasopharyngeal airway assisted ventilation undergoing ureteroscopic holmium laser lithotripsy: A prospective, single-center, controlled trial

To observe the effect of intravenous general anesthesia under nasopharyngeal airway-assisted ventilation on patients undergoing ureteroscopic holmium laser lithotripsy. One hundred and twenty patients who underwent ureteroscopic holmium laser lithotripsy in our hospital were selected and randomly divided into nasopharyngeal airway group (research group) and laryngeal mask group (control group). These patients, respectively, received intravenous anesthesia under nasopharyngeal airway and laryngeal mask-assisted ventilation. The following evaluation indexes were compared and analyzed between the two groups, including anesthetic effect, hemodynamics, stress response, postoperative recovery, adverse reactions, etc. There were no significant differences in Visual Analog Scale, hemodynamics, and stress response between the two groups at each time point (P > 0.05). There were no significant differences in residence time and postoperative recovery time between the two groups (P > 0.05). The difference in airway establishment time between the two groups was statistically significant (P < 0.05), and cases with blood in the research group was significantly lower than those in the control group (P < 0.05). Patient satisfaction in research group was significantly higher than those in the control group (P < 0.05). The clinical effect of intravenous general anesthesia under nasopharyngeal airway-assisted ventilation in ureteroscopic holmium laser lithotripsy is significant, which helps to stabilize patients' hemodynamics, reduce their stress response and adverse reactions, and improve the satisfaction rate of patient.

The Effect of Anesthesia Type on the Stability of the Surgical View on the Monitor in Retrograde Intrarenal Surgery for Renal Stone: A Prospective Observational Trial

Background and Objectives: Retrograde intrarenal surgery (RIRS) is a minimally invasive technique for nephrolithiasis. RIRS is performed via a monitor screen displaying a magnified surgical site. Respiration can affect the stability of the surgical view during RIRS because the kidneys are close to the diaphragm. The purpose of this trial is to compare the effect of anesthesia type on the stability of the surgical view during RIRS between spinal anesthesia and general anesthesia. Materials and Methods: Patients were allocated to the general anesthesia group or spinal anesthesia group. During surgery, movement of the surgical field displayed on the monitor screen was graded by the first assistant on a 10-grade numeric rating scale (0-10). Next, it was also graded by the main surgeon. After surgery, we evaluated the discomfort with the anesthesia method for all patients. Results: Thirty-four patients were allocated to the general anesthesia group and 32 patients to the spinal anesthesia group. The average values of the two surgeons for surgical field oscillation grade showed vision on the monitor screen was more stable in the general anesthesia group than the spinal anesthesia group (3.3 ± 1.6 vs. 5.0 ± 1.6, p < 0.001). The degrees of the inconvenience of the surgery did not differ between the groups (0.7 ± 1.8 vs. 1.6 ± 2.6, p = 0.114), even though more patients reported inconvenience with a grade of 3 or more in the spinal anesthesia group (8.8% vs. 28.1%, p = 0.042). Conclusions: In terms of the visualization of the surgical site, general anesthesia might provide a more stable surgical view during RIRS compared to spinal anesthesia without increasing inconvenience induced by the type of anesthesia.

Prevention and Management of Infectious Complications in Retrograde Intrarenal Surgery: A Comprehensive Review

Retrograde intrarenal surgery (RIRS) is a minimally invasive procedure increasingly used to treat renal stones and other intrarenal pathologies due to its reduced risk of complications, shorter recovery time, and lower postoperative pain compared to more invasive surgical techniques. However, despite its advantages, RIRS is associated with a significant risk of infectious complications, ranging from simple urinary tract infections (UTIs) to severe systemic infections such as urosepsis, which can lead to increased morbidity, prolonged hospitalization, and, in severe cases, mortality. This review aims to summarize the current knowledge on preventing and managing infectious complications associated with RIRS. By exploring the pathophysiology of these infections, identifying patient and procedural risk factors, and evaluating evidence-based strategies for prevention and management, this review provides comprehensive insights into minimizing infection risks in RIRS. A thorough literature review was conducted, examining studies and clinical trials that address the incidence, risk factors, prevention strategies, and management protocols for infections in RIRS. This review also assesses current guidelines from professional organizations and recent infection control technologies and practices advancements. The review identifies multiple risk factors contributing to infections in RIRS, including patient-specific factors such as comorbidities and procedural factors like the duration of surgery and use of instrumentation. Effective prevention strategies include preoperative antibiotic prophylaxis, stringent aseptic techniques during surgery, and careful postoperative monitoring. The review also highlights the importance of a multidisciplinary approach involving urologists, infectious disease specialists, and microbiologists in managing complex cases of infection. Infectious complications remain a significant concern in RIRS, necessitating a comprehensive approach to prevention and management. By adhering to evidence-based guidelines and utilizing a multidisciplinary strategy, healthcare professionals can significantly reduce the incidence of infections, thereby improving patient outcomes and the overall safety of RIRS. Future research should focus on advancing infection control technologies and developing novel prophylactic and therapeutic approaches to further enhance the safety and effectiveness of RIRS.

Ureteral access sheaths in RIRS: a retrospective, comparative, single-center study

OBJECTIVES

To evaluate the use of ureteral access sheaths (UAS) in reducing operative time and complications, as well as improving stone-free rates (SFR), while assessing their overall safety and efficiency.

METHODS

Data regarding 234 patients who underwent retrograde intrarenal surgery (RIRS) for stones up to 3 cm between January 2017 and March 2020 were retrospectively analyzed. About 52.5 % of procedures were performed utilizing a UAS. Differences in operative time, fluoroscopy time, stone-free rate, and complications were analyzed between procedures with and without UAS and stratified, according to stone burden size, into three groups (Group A: 0.5-1 cm; Group B: 1-2 cm; Group C: 2-3 cm).

RESULTS

Operative time, fluoroscopy time, and residual fragments size were lower in RIRS without UAS, respectively, 54.27 ± 24.02 vs. 62.23 ± 22.66 min (p=0.010), 2.72 ± 0.89 vs. 4.44 ± 1.67 min (p<0.0001), and 3.85 ± 0.813 vs. 4.60 ± 0.83 mm (p=0.011). Considering stone burden, operative time was lower in RIRS without UAS for Group A (36.40 ± 8.555 vs. 46.05 ± 6.332 min) (p<0.0001) while higher for Group B (60.39 ± 18.785 vs. 50.14 ± 5.812 min) (p=0.002). Similarly, fluoroscopy time was lower in RIRS without UAS in every group, respectively, 2.11 ± 0.34 vs. 2.74 ± 0.57 min (p<0.0001), 2.94 ± 0.51 vs. 4.72 ± 0.37 min (p<0.0001), and 3.78 ± 1.26 vs. 6.79 ± 1.17 min (p<0.0001). Only Group C had a statistically significant difference in residual fragment size without UAS (3.89 ± 0.782 vs. 4.75 ± 0.886 mm) (p=0.050).

CONCLUSIONS

UAS should be carefully evaluated considering the increased fluoroscopy time and the differences in operative time related to different stone burdens.

The mayo adhesive probability score predicts postoperative fever and sepsis in retrograde intrarenal surgery

Infectious complications are among the most common and potentially life-threatening morbidities of retrograde intrarenal surgery (RIRS). Few predictive tools on these complications include radiological signs. The Mayo adhesive probability (MAP) score is an image-based scoring system that incorporates two radiological signs: perinephric fat stranding and perinephric fat thickness. Previous studies have suggested an association between these signs and febrile urinary tract infection (UTI) following lithotripsy. This study aimed to evaluate the predictive factors, including the MAP score, for post-RIRS fever and sepsis. A total of 260 patients who underwent 306 RIRS between October 2019 to December 2023 due to renal or upper ureteral stones were included in this retrospective study. Patient demographics, perioperative characteristics, stone factors, radiological signs, and MAP scores were recorded. Multivariate logistic regression analysis was used to evaluate the risk factors associated with postoperative fever and sepsis. Postoperative fever and sepsis occurred in 20.8% and 8.5% of the patients, respectively. On multivariate analysis, female gender, history of recurrent UTI, larger maximal stone diameter, and higher MAP score were independent risk factors for postoperative fever and sepsis. Identifying the risk factors for post-RIRS infectious complications is imperative to providing the proper perioperative management. The MAP score is a promising, easily calculated, image-based scoring system that predicts post-RIRS fever and sepsis.

Radiation exposure of patients during endourological procedures

PURPOSE

Considering the existing gaps in the literature regarding patient radiation dose (RD) and its associated risks, a systematic review of the literature on RD was conducted, focusing on percutaneous nephrolithotomy (PCNL), extracorporeal shock wave lithotripsy (SWL), and ureteroscopy (URS).

METHODS

Two authors conducted a literature search on PubMed, Web of Science, and Google Scholar to identify studies on RD during endourological procedures. Two thousand two hundred sixty-six articles were screened. Sixty-five publications met the inclusion criteria using the PRISMA standards.

RESULTS

RD was generally highest for PCNL, reaching levels up to 33 mSv, 28,700 mGycm2, and 430.8 mGy. This was followed by SWL, with RD reaching up to 7.32 mSv, 13,082 mGycm2, and 142 mGy. URS demonstrated lower RD, reaching up to 6.07 mSv, 8920 mGycm2, and 46.99 mGy. Surgeon experience and case load were inversely associated with RD. Strategies such as optimizing fluoroscopy settings, implementing ultrasound (US), and following the ALARA (As Low As Reasonably Achievable) principle minimized RD.

CONCLUSIONS

This is the first systematic review analyzing RD, which was generally highest during PCNL, followed by SWL and URS. There is no specific RD limit for these procedures. Implementation of strategies such as optimizing fluoroscopy settings, utilizing US, and adhering to the ALARA principle proved effective in reducing RD. However, further research is needed to explore the factors influencing RD, assess their impact on patient outcomes, and establish procedure-specific reference levels for RD.

Cumulative sum analysis of the learning curve for retrograde intrarenal stone surgery in newbie surgeons

INTRODUCTION

This study investigated the learning curve of retrograde intrarenal surgery (RIRS) in patients with medium-sized stones using cumulative sum analysis (CUSUM) to evaluate the competence and proficiency of three new surgeons during their first RIRS procedures.

MATERIALS AND METHODS

We conducted a retrospective review of 227 patients from 2019 to 2022 at a single institution. The patients were divided into four groups based on the operating surgeon: tutor surgeon (85 patients), newbie surgeon A (21 patients), newbie surgeon B (85 patients), and newbie surgeon C (36 patients). Patients had one or multiple stones with the largest stone diameter fell within the range of 10-30 mm. Fragmentation efficacy was calculated as "removed stone volume (mm3) divided by operative time (minutes)." CUSUM analysis monitored changes in fragmentation efficacy and validated surgical outcomes.

RESULTS

No statistically significant differences were observed in the total stone volume, maximum stone size, or total operation time between the three newbie surgeons and the tutor surgeon. The mean fragmentation efficacy value was comparable among the newbie surgeons, but significantly different from that of the tutor surgeon. The minimum acceptable fragmentation efficacy level was set at 25.12 mL/min, based on the tutor's average value. The CUSUM curves for the three surgeons initially remained relatively flat until Cases 12-15, after which they increased and eventually plateaued. Stone-free rates and postoperative complications did not differ significantly among the surgeons.

CONCLUSION

Learning curve analysis for the three newbie surgeons indicated that approximately 12-15 cases were required to reach a plateau.

Prospective Evaluation of Risk Factors Responsible for Infection Following Retrograde Intrarenal Surgery

OBJECTIVE

The study aimed to identify the various risk factors for infective complications following retrograde intrarenal surgery (RIRS).

MATERIALS AND METHODS

The study was conducted over one year, and the incidence of infectious complications after RIRS was calculated. Patients were divided into two groups based on the presence and absence of infective complications and were compared in terms of preoperative and operative characteristics. The complications were assessed and graded according to the Modified Clavien classification system (MCCS). The Fisher's exact test, Student's t-test, and Mann-Whitney U test were used for univariate analysis. Multivariate logistic regression analysis was used to identify independent risk factors for postoperative urinary tract infection (UTI).

RESULTS

Out of 165 patients in the study, 27 (16.7%) patients developed UTI within one month of undergoing RIRS. The most frequent complication was fever, which occurred in 13 (7.8%) patients. When stratified by MCCS, 13 were grade I, nine were grade II, four were grade III, and one was a grade IV complication. High stone burden, concomitant diabetes mellitus, and multiple renal stones were identified as substantial risk factors for postoperative UTI in univariate analysis. On multivariate analysis, preoperative UTI and prolonged operative time were found to have a significant association with postoperative UTI.

CONCLUSION

The present study demonstrated that preoperative UTI and prolonged operative time are independent factors responsible for postoperative UTI. Large stone burden, stone multiplicity, and diabetes mellitus contribute to a higher risk for UTI following RIRS.

Flexible ureteroscopy with novel flexible ureteral access sheath versus mini-percutaneous nephrolithotomy for treatment of 2-3 cm renal stones

OBJECTIVES

To assess and compare the effectiveness and safety of flexible ureteroscopy (f-URS) with a novel flexible ureteral access sheath (f-UAS) versus mini-percutaneous nephrolithotripsy (mini-PCNL) in treating 2-3 cm renal stones.

METHODS

Retrospectively analyzed consecutive cases that underwent f-URS with f-UAS (12/14 Fr) from January 29, 2022, to November 30, 2022. Consecutive cases that underwent mini-PCNL (18 Fr) from June 5, 2021, to January 26, 2022, were selected as controls. The f-UAS is a novel device with a 10 cm anterior tip that passively bends along with the f-URS to enter the renal calyx. We analyzed demographic characteristics, stone parameters, operative time, stone-free rates (SFR), hospitalization time, and complication.

RESULTS

A total of 96 consecutive cases that underwent f-URS with f-UAS and 96 consecutive cases that underwent mini-PCNL were included in the study. There were no significant differences between the two groups in terms of operative time (p = 0.06), stone volume clearance (p = 0.533) and complete SFR (p = 0.266) on the first postoperative day or residual Stone after 1 month (p = 0.407). We observed a significantly shorter postoperative hospital stay (1.4 days vs. 2.1 days; p < 0.001) and a lower decrease in hemoglobin levels (0.39 g/dL vs. 0.68 g/dL; p < 0.001) in the f-UAS group. The mini-PCNL group had a significantly higher overall complication rate (13.5%) compared with the f-UAS group (5.2%; p = 0.048).

CONCLUSIONS

In the treatment of 2-3 cm renal stones, f-URS with a novel f-UAS may provide a superior alternative to mini-PCNL, potentially challenging its established status.

PCNL vs. two staged RIRS for kidney stones greater than 20 mm: systematic review, meta-analysis, and trial sequential analysis

INTRODUCTION

Percutaneous nephrolithotomy (PCNL) is considered the gold standard treatment for kidney stones greater than 20 mm. However, retrograde intrarenal surgery (RIRS) may achieve the same stone-free rate with repeated procedures, and potentially fewer complications. This study aimed to compare the efficacy and safety of PCNL and two-staged RIRS.

EVIDENCE ACQUISITION

We conducted a systematic search in PubMed, Embase, Scopus, Cochrane, and Web of Science for studies comparing PCNL and RIRS for kidney stones greater than 20mm. The primary outcome is stone-free rate (SFR) of PCNL and RIRS (repeated once if needed). Secondary outcomes were SFR of PCNL versus RIRS (single procedure), operative time, hospital stay, need for auxiliary procedures, and complications. We performed a subgroup analysis for randomized trials, non-randomized trials, and patients with solitary kidney. We performed a trial sequential analysis for the main outcome.

EVIDENCE SYNTHESIS

We included 31 articles, with 1987 patients in the PCNL and 1724 patients in RIRS. We confirmed the traditional result that after a single procedure PCNL has a higher SFR. We also found that comparing the SFR of PCNL and RIRS, repeated up to two times if needed, no difference in SFR was observed. Surprisingly, only 26% (CI95 23%-28%) of the patients required a second RIRS. In the trial sequential analysis, the last point of the z-curve was within futility borders. We observed that PCNL has a higher incidence of complications (RR=1.51; CI95 1.24, 1.83; P<0.0001; I2=28%), specifically CD2 (RR=1.82; CI95 1.30, 2.54; P=0.0004; I2=26%) and longer hospital stay (MD 2.57; 2.18, 2.96; P<0.00001; I2-98%). No difference was observed regarding operative time.

CONCLUSIONS

RIRS repeated up to two times is equivalent to PCNL in terms of the SFR and may have the same safety.

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.

Fluoroscopy Is Essential in Retrograde Intrarenal Surgery

Objective

This study aimed to investigate the necessity of using fluoroscopy in retrograde intrarenal surgery (RIRS). Material and Methods. A total of 612 patients who underwent RIRS for kidney stones were evaluated and divided into two groups. Group 1 routinely underwent the operation with fluoroscopy due to opaque stones (n: 504). In group 2, the procedure was performed without fluoroscopy because of nonopaque stones (n: 108). Both groups were assessed for stone size, location, and number. Success and complication rates were compared between the two groups.

Conclusion

This study was designed with the thought of not using fluoroscopy in RIRS patients with nonopaque stones and having the same stone-free rates in opaque stones. In the statistical analysis, there was no difference between the groups with and without scope for stone side, size, localization, and number; likewise, the complication rates developed in the comparison of both groups, stone-free rates, and hospital stay were the same. Discussion. Advances in the calibration of instruments, the development of optical systems, and improvements in imaging system resolution have gradually reduced the need for fluoroscopy in RIRS. This study provides further evidence that fluoroscopy is unnecessary in RIRS procedures, thereby eliminating unnecessary radiation exposure.

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.

Flexible ureteroscopy for lower pole calculus: is it still a challenge?

PURPOSE

Flexible ureteroscopy (fURS) is steadily gaining popularity in the management of renal calculi, including those located in the lower pole (LP). Due to difficulty in accessing to the LP of kidney in minority of cases with fURS and reports of lower stone-free rate (SFR), it is still considered as a challenge in selected cases. The purpose of the review was to analyze the various aspects of fURS for LP stones.

METHODS

An extensive review of the recent literature was done including different factors such as anatomy, preoperative stenting, stone size, flexible scopes, types of lasers, laser fibers, suction, relocation, stone-free rates, and complications.

RESULTS

The significance of various lower pole anatomical measurements remain a subject of debate and requires standardization. Recent improvements in fURS such as single-use digital scopes with better vision and flexibility, high power laser, thulium fiber laser, smaller laser fiber, and accessories have significantly contributed to make flexible ureteroscopy  more effective and safer in the management of LP stone. The utilization of thulium fiber lasers in conjunction with various suction devices is being recognized and can significantly improve SFR.

CONCLUSIONS

With the significant advancement of various aspects of fURS, this treatment modality has shown remarkable efficacy and gaining widespread acceptance in management of LP kidney stones. These developments have made the fURS of LP stones less challenging.

[THRIVE combined with i-gel laryngeal mask for prolonging apneic oxygenation time in retrograde intrarenal surgery]

OBJECTIVE

To explore the effect of THRIVE combined with i-gel laryngeal mask on the safety of oxygen therapy in apnea and surgical precision of retrograde intrarenal surgery.

METHODS

A total of 120 patients undergoing retrograde intrarenal surgery under general anesthesia with laryngeal mask were randomized into 3 groups (n=40), and after the flexible ureteroscope entered the renal pelvis and located the stones, the patients received assisted ventilation in APPV mode (control group), ventilation with small tidal volume and high respiratory rate (group H), or THRIVE combined with laryngeal mask for oxygen supply without using the ventilator (THRIVE group). The time for lithotripsy by the surgeons, surgeons' satisfaction, diaphragm mobility, and times of urinary tract mucosal injury were recorded, and arterial blood pressure, heart rate, SpO2, PaO2, PaCO2, and pH value were measured before, during and after lithotripsy.

RESULTS

Among the 3 groups, THRIVE group had the shortest time for lithotripsy, best satisfaction of the surgeons, the lowest diaphragmatic mobility of the patients, and the smallest number of mucosal injuries. The arterial blood pressure, heart rate, and SpO2 of the patients did not differ significantly among the 3 groups. At 20 min and 30 min after the start of lithotripsy, PaO2 decreased significantly in group H and THRIVE group; in THRIVE group, PaCO2 increased and pH decreased significantly at 10, 20 and 30 min after the start of lithotripsy. No significant difference was found in oxygenation indicators among the 3 groups upon discharge from the PACU.

CONCLUSION

In retrograde intrarenal surgery, THRIVE combined with i- gel laryngeal mask for oxygen therapy during the anaerobic period can improve the surgical accuracy and maintain the patient's oxygenation index in a controllable range within 30 min.

Evaluation of ultrathin semirigid ureteroscopy in terms of efficiency and cost compared to flexible ureteroscopy in treating proximal ureteric stones: a prospective randomized multicenter study

PURPOSE

To investigate the outcome and cost-effectiveness of ultrathin 6-7.5-Fr semirigid ureteroscopy in treating proximal ureteric stones compared to flexible ureteroscopy.

METHODS

Two hundred and twenty patients with a solitary proximal ureteric stone were eligible for ureteroscopy (stone size = 1-2 cm). Patients were randomly subdivided into two groups: Group I included 105 patients who underwent ultrathin semirigid ureteroscopy and group II included 115 patients who underwent flexible ureteroscopy. Both groups were compared regarding successful stone access, operation time, reoperation rates, the financial cost to stone-free, complications, and stone clearance at 4 and 8 weeks.

RESULTS

Groups I and II had no significant differences regarding patient demographics, stone criteria, and hospitalization time. In contrast, the mean operative time was significantly longer in group II (p < 0.001). The overall scope-to-stone access rate was 89.5%. It was 87.6% compared to 91.3% (p = 0.32), while the stone-free rate was 81.9% versus 87.8% (p = 0.22) for groups I and II, respectively. Intraoperative and postoperative complications were statistically insignificant between the study groups. The cost/person in Egyptian pounds was 8619 ± 350 in group I, compared to 17,620 ± 280 in group II (p < 0.001); similarly, the cost to attain the stone-free rate was 8950 ± 720 in group I compared to 17,950 ± 500 in group II.

CONCLUSION

Ultrathin semirigid ureteroscopy is safe, durable, and considered a cost-effective method for treating upper ureteric calculi compared to the flexible ureteroscopy and could be considered a first treatment option in developing countries.

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.

A systematic review and meta-analysis of outcomes between dusting and fragmentation in retrograde intrarenal surgery

OBJECTIVES

Comparing stone-free rates and associated outcome measures between two surgical modalities of lithotripsy fragmentation and removal or spontaneous passage of dust during retrograde intrarenal surgery (RIRS).

METHODS

In March 2023, we conducted a literature search in several widely used databases worldwide, including PubMed, Embase, and Google Scholar. We only considered English articles and excluded pediatric patients. Reviews and protocols without any published data were excluded. We also excluded articles with conference abstracts and irrelevant content. We used the Cochran-Mantel-Haenszel method and random-effects models to assess inverse variances and 95% confidence intervals (CIs) for mean differences in categorical variables. The results were reported as odds ratios (ORs) and 95% CIs. Statistical significance was set at p < 0.05.

RESULTS

Our final meta-analysis included nine articles, comprising two randomized controlled trials (RCTs) and seven cohort studies. The total number of patients included in these studies was 1326, and all studies used holmium laser lithotripsy. The pooled analysis of the dust and fragmentation groups showed that the fragmentation group had a higher stone-free rate (OR 0.6; 95% CI 0.41 - 0.89; p = 0.01); the dust group had a shorter operative time (WMD - 11.6 min; 95% CI - 19.56 - -3.63; p = 0.004); and the dust group had a higher retreatment rate (OR 2.03; 95% CI 1.31 - 3.13; p = 0.001). There was no statistically significant difference between the two groups in terms of length of hospital stay, overall complications, or postoperative fever.

CONCLUSIONS

Our results showed that both procedures could be safely and effectively used for upper ureteral and renal calculi lithotripsy, the dust group had potential advantages over the fragmentation group in terms of the operation time, and the fragmentation group had certain advantages in terms of stone-free rate and retreatment rate.

Comparison of commonly utilized ureteral access sheaths: A prospective randomized trial

OBJECTIVE

We aimed to evaluate and compare the functional characteristics, safety profile and effectiveness of two commonly used ureteral access sheaths (UAS) during flexible ureteroscopy.

METHODS

After institutional review board approval, patients with proximal ureteral or kidney stones requiring flexible ureteroscopy and UAS were prospectively randomized to group I or group II according to the type of access sheath used. Primary outcome was incidence of intraoperative complications.

RESULTS

Eighty-eight patients were enrolled in the study, 44 patients in each group. Sheath size 12/14 FR was used in both cohorts. Median (IQR) stone size was 10 mm (7-13.5) and 10.5 mm (7.37-14) in group I and II respectively (p = 0.915). Nineteen and twenty patients, in group I and II respectively, were pre-stented. Subjective resistance with insertion of the UAS was observed in 9 and 11 patients in group I and II respectively (p = 0.61) while failed insertion was encountered in one patient in group I. Traxer grade 1 ureteral injury was noted in 5 and 6 patients in group I and II respectively while grade 3 injury was seen in 1 patient for both cohorts (p = 0.338). There was less resistance for UAS placement in pre-stented patients (p = 0.0202) but without significant difference in ureteric injury incidence (p = 0.175). Emergency department visits were encountered in 7 (group I) and 5 patients (group II) (p = 0.534).

CONCLUSIONS

The studied UASs were comparable regarding safety and efficacy in the current study. Pre-stented and dilated ureters had less resistance to insertion although this was not reflected on incidence of ureteric injury.

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.

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.

Impact of Preoperative Ureteral Stenting in Retrograde Intrarenal Surgery for Urolithiasis

Background and Objectives: Ureteral stent insertion passively dilates the ureter. Therefore, it is sometimes used preoperatively before flexible ureterorenoscopy to make the ureter more accessible and facilitate urolithiasis passage, especially when ureteroscopic access has failed or when the ureter is expected to be tight. However, it may cause stent-related discomfort and complications. This study aimed to assess the effect of ureteral stenting prior to retrograde intrarenal surgery (RIRS). Materials and Methods: Data from patients who underwent unilateral RIRS for renal stone with the use of a ureteral access sheath from January 2016 to May 2019 were retrospectively analyzed. Patient characteristics, including age, sex, BMI, presence of hydronephrosis, and treated side, were recorded. Stone characteristics in terms of maximal stone length, modified Seoul National University Renal Stone Complexity score, and stone composition were evaluated. Surgical outcomes, including operative time, complication rate, and stone-free rate, were compared between two groups divided by whether preoperative stenting was performed. Results: Of the 260 patients enrolled in this study, 106 patients had no preoperative stenting (stentless group), and 154 patients had stenting (stenting group). Patient characteristics except for the presence of hydronephrosis and stone composition were not statistically different between the two groups. In surgical outcomes, the stone-free rate was not statistically different between the two groups (p = 0.901); however, the operation time for the stenting group was longer than that of the stentless group (44.8 ± 24.2 vs. 36.1 ± 17.6 min; p = 0.001). There were no differences in the complication rate between the two groups (p = 0.523). Conclusions: Among surgical outcomes for RIRS with a ureteral access sheath, preoperative ureteral stenting does not provide a significant advantage over non-stenting with respect to the stone-free rate and complication rate.

Pelvicalyceal anatomy on the accessibility of reusable flexible ureteroscopy to lower pole calyx during retrograde intrarenal surgery

OBJECTIVE

This study aimed to evaluate the pelvicalyceal anatomy on accessibility of reusable flexible ureteroscopy (fURS) to the lower pole calyx during retrograde intrarenal surgery (RIRS).

METHODS

Here, 854 patients with ureteral or kidney stones with access to a renal collecting system using reusable fURS were classified into either the accessible group, in whom the deepest lower pole calyces could be touched; and the inaccessible group, in whom the deepest lower calyces could not be touched. We measured the infundibulopelvic angle (IPA), infundibular width (IW), infundibular length (IL), and calyceal pelvic height (CPH) using retrograde pyelograms and performed intergroup comparisons.

RESULTS

The median IPA, IW, IL, and CPH in the accessible and inaccessible group were 60.5° and 45.6° (p < 0.001), 10.8 and 9.4 mm (p < 0.001), 33.2 and 36.4 mm (p < 0.001), and 25.9 and 30.9 mm (p < 0.001), respectively. IPA (OR 0.963, 95% CI 0.952-0.974, p < 0.001) and IW (OR 0.519, 95% CI 0.331-0.816, p = 0.004) were significant risk factors of renal pelvicalyceal anatomy related to the accessibility of the lower pole calyces. The cut-off value for IPA and IW was 45.8°(p < 0.001) and 7.8 mm (p < 0.001), respectively.

CONCLUSIONS

IPA < 45.8° and IW <7.8 mm were negative predictors to access the lower pole calyces when using reusable fURS during RIRS.

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)

PURPOSE

To collect a multicentric database on behalf of TOWER research group to assess practice patterns and outcomes of retrograde intrarenal surgery (RIRS) for kidney stones.

METHODS

Inclusion criteria: age ≥ 18 years, normal renal/calyceal system anatomy, calculi of any size, number, and position.

STUDY PERIOD

January 2018 and August 2021. Stone-free status: absence of fragments > 2 mm, assessed post procedure according to the local protocol (KUB X-Ray and/or ultrasound or non-contrast CT scan).

RESULTS

Twenty centers from fifteen countries enrolled 6669 patients. There were 4407 (66.2%) men. Mean age was 49.3 ± 15.59 years. Pain was the most frequent symptom indication for intervention (62.6%). 679 (10.2%) patients underwent RIRS for an incidental finding of stones. 2732 (41.0%) patients had multiple stones. Mean stone size was 10.04 ± 6.84 mm. A reusable flexible ureteroscope was used in 4803 (72.0%) procedures. A sheath-less RIRS was performed in 454 (6.8%) cases. Holmium:YAG laser was used in 4878 (73.1%) cases. A combination of dusting and fragmentation was the most common lithotripsy mode performed (64.3%). Mean operation time was 62.40 ± 17.76 min. 119 (1.8%) patients had an intraoperative injury of the ureter due to UAS insertion. Mean postoperative stay was 3.62 ± 3.47 days. At least one postoperative complication occurred in 535 (8.0%) patients. Sepsis requiring intensive care admission occurred in 84 (1.3%) patients. Residual fragments were detected in 1445 (21.7%) patients. Among the latter, 744 (51.5%) patients required a further intervention.

CONCLUSION

Our database contributes real-world data to support to a better understanding of modern RIRS practice and outcomes.

Single-Session Impact of High-Power Laser with Moses Technology for Lower Pole Stones in Retrograde Intrarenal Surgery: Retrospective Study

Background: This study aimed to evaluate the efficacy of a high-power holmium laser with Moses technology (MT) for the treatment of lower pole stones during retrograde intrarenal surgery (RIRS). Methods: Herein, 305 patients with lower pole stones who underwent RIRS using a high-power holmium laser with MT were retrospectively classified into the stone-free (SF) and non-SF groups. We measured the stone burden, stone volume, stone hardness, pre- or post-operative stent placement, infundibulopelvic angle (IPA), infundibular width (IW), infundibular length (IL), and calyceal pelvic height in terms of pelvicalyceal anatomy using retrograde pyelograms and evaluated the predictive factors of postoperative SF. Results: A total of 173 (56.7%) and 229 (75.1%) patients achieved a SF status on postoperative day one and at one month, respectively. Operation time in the SF group was shorter than that in the non-SF group (51.0 vs. 74.5 min). There were no significant differences in postoperative complications between the SF and non-SF groups. Significantly predictive risk factors in postoperative SF included total stone volume (odds ratio (OR), 1.056; 95% CI, 1.015-1.099; p = 0.007), IPA (OR, 0.970; 95% CI, 0.956-0.993; p = 0.009), and IW (OR, 0.295; 95% CI, 0.121-0.718; p = 0.007). The cut-off values of stone volume, IPA, and IW were 515.2 mm³, 46.8°, and 7.75 mm, respectively. Conclusions: A high-power holmium laser with MT in lower pole stones is a valuable option for positive outcomes and patient's safety. Larger stone volume, acute IPA, and narrow IW were negative predictors related to postoperative SF status.

The impact of Hounsfield unit-related variables on percutaneous nephrolithotomy outcomes

We aimed to identify the association between Hounsfield Unit(HU)-related variables and percutaneous nephrolithotomy (PCNL) outcomes. We enrolled patients with single renal stones (1-3 cm) who underwent single-tract PCNL between January 2014 and October 2019. Demographics and stone characteristics were retrospectively reviewed. Preoperative computerized tomography (CT) and follow-up CT within at least 3 months after PCNL were included in this analysis. Stone-free status was defined as residual stone measuring ≤ 2 mm within 3 months postoperatively. HU and cross-sectional area (CSA) were measured using the free-draw technique. We analyzed HU-related variables using logistic regression model for outcomes. Altogether, 188 out of 683 patients met the inclusion criteria. The stone-free rate (SFR) was 79.2%. There were no significant differences in age, sex, BMI, ASA class, laterality, pre-op shockwave lithotripsy, stone size, stone burden, skin-to-stone distance, and HU between the stone-free and remnant groups. CSA and HU/CSA in the stone-free and remnant groups were 94.5 ± 46.1 and 128.3 ± 98.5 (p = 0.043) and 10.1 ± 5.6 and 7.3 ± 3.4 (p = 0.001), respectively. Multivariate logistic regression analysis revealed that pelvis, ureteropelvic junction stones, and HU/CSA were independent predictors of SFR. HU did not affect PCNL outcomes. We believe that HU/CSA could be used for determining stone treatment plans and predicting outcomes.

Safety enhanced surgical robot for flexible ureteroscopy based on force feedback

BACKGROUND

Although some robotic systems have been developed to improve conventional flexible ureteroscopy (FURS), a widely used intervention in urology, these robots rarely have a comprehensive force feedback function which is important for master-slave controlled surgical robots.

METHODS

Here, we design and fabricate a novel FURS robot with a comprehensive force feedback function. Moreover, to realize better force feedback, a neural network-based method is also demonstrated to estimate the interactive forces between the flexible ureteroscope and the environment.

RESULTS

We show that when teleoperating the flexible ureteroscope with our robot, the operator can accurately feel the obstruction if the interactive axial force or torque exceeds 1.2 N or 15.6 mN·m respectively. For bending movement, augmented force feedback greatly improves the accuracy of the operator's perception of obstruction.

CONCLUSIONS

The developed robotic system with force feedback is expected to improve the safety of robot-assisted FURS.

Technique, Feasibility, Utility, Limitations, and Future Perspectives of a New Technique of Applying Direct In-Scope Suction to Improve Outcomes of Retrograde Intrarenal Surgery for Stones

Retrograde intrarenal surgery (RIRS) is accepted as a primary modality for the management of renal stones up to 2 cm. The limitations of RIRS in larger volume stones include limited visualization due to the snow-globe effect and persistence of fragments that cannot be removed. We describe a new, simple, cost-effective modification that can be attached to any flexible ureteroscope which allows simultaneous/alternating suction and aspiration during/after laser lithotripsy using the scope as a conduit to remove the fragments or dust from the pelvicalyceal system called direct in-scope suction (DISS) technique. Between September 2020 and September 2021, 30 patients with kidney stones underwent RIRS with the DISS technique. They were compared with 28 patients who underwent RIRS with a 11Fr/13Fr suction ureteral access sheaths (SUASs) in the same period. RIRS and laser lithotripsy were carried out traditionally with a Holmium laser for the SUAS group or a thulium fiber laser for the DISS group. There was no difference in age, gender, and history of renal lithiasis between the two groups. Ten (40%) patients had multiple stones in the DISS groups, whilst there were no patients with multiple stones in the SUAS group. Median stone size was significantly higher in the DISS group [22.0 (18.0−28.8) vs. 13.0 (11.8−15.0) millimeters, p < 0.001]. Median surgical time was significantly longer in the DISS group [80.0 (60.0−100) minutes] as compared to the SUAS group [47.5 (41.5−60.3) minutes, p < 0.001]. Hospital stay was significantly shorter in the DISS group [1.00 (0.667−1.00) vs. 1.00 (1.00−2.00) days, p = 0.02]. Postoperative complications were minor, and there was no significant difference between the two groups. The incidence of residual fragments did not significantly differ between the two groups [10 (33.3%) in the DISS group vs. 10 (35.7%) in the SUAS group, p = 0.99] but 10 (33.3%) patients required a further RIRS for residual fragments in the DISS group, whilst only one (3.6%) patient in the SUAS group required a subsequent shock wave lithotripsy treatment. Our audit study highlighted that RIRS with DISS technique was feasible with an acceptable rate of retreatment as compared to RIRS with SUAS.

Comparison and outcomes of dusting versus stone fragmentation and extraction in retrograde intrarenal surgery: results of a systematic review and meta-analysis

INTRODUCTION

Lithotripsy during retrograde intrarenal surgery (RIRS) can be achieved either by fragmentation and extraction or dusting with spontaneous passage. We aimed to perform a systematic review on the safety and stone-free rate after RIRS by comparing the techniques of dusting vs fragmentation/extraction.

MATERIAL AND METHODS

This review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. The inverse variance of the mean difference and 95% Confidence Interval (CI), Categorical variables were assessed using Cochran-Mantel-Haenszel Method with the random effect model and reported as Odds Ratio (OR) and 95% CI. Statistical significance was set at p <0.05.

RESULTS

There were 1141 patients included in 10 studies. Stone size was up to 2.5 cm All studies used holmium laser for lithotripsy. Meta-analysis showed no significant difference in surgical time (MD -5.39 minutes 95% CI -13.92-2.31, p = 0.16), postoperative length of stay (MD -0.19 days 95% CI -0.60 - -0.22, p=0.36), overall complications (OR 0.98 95% CI 0.58-1.66, p = 0.95), hematuria (OR 1.01 95% CI 0.30-3.42, p = 0.99), postoperative fever (OR 0.70 95% CI 0.41-1.19, p = 0.19) and sepsis (OR 1.03 95% CI 0.10-10.35, p = 0.98), immediate (OR 0.40 95% CI 0.13-1.24, p = 0.11) and overall stone-free rate (OR 0.76 95% CI 0.43-1.32, p = 0.33), and retreatment rate (OR 1.35 95% CI 0.57-3.20, p = 0.49) between the groups.

CONCLUSIONS

This systematic review infers that urologists can safely use either option of fragmentation and basket extraction or dusting without extraction to achieve similar outcomes as both techniques are similar for efficacy and safety.

Primary impact of simultaneous use of double devices through one-working channel when performing flexible ureteroscope with ureteral access sheath for single ureteral stone: In bench and retrospective clinical study

OBJECTIVES

This study aimed to compare the simultaneous use of two devices versus a single device through a single working channel in flexible ureteroscopy using a ureteral access sheath for single ureteral stones.

METHODS

In a bench study, the time to (i) set laser fiber, (ii) exchange laser fiber and nitinol basket through working channel, and (iii) pull out the device from working channel were measured 10 times in each step. In a clinical study, 156 patients who underwent flexible ureteroscopy with a ureteral access sheath for a ureteral stone in middle and upper ureter between April 2019 and November 2021 were assessed. One device was used at a time for 79 patients (S-Group) and two were simultaneously used for 77 (D-Group). Surgical outcomes and complications were compared.

RESULTS

In the bench study, the mean time to change from laser fiber to basket and from basket to laser fiber through the working channel were 26.1 ± 3.7 s and 23.6 ± 2.0 s (p = 0.084), respectively, which were significantly longer than the laser setup time (p < 0.001). In the clinical study, although the stone-free rate was not significantly different between the groups (S-Group 89.8%, D-Group 93.5%; p = 0.412), the median operation time was significantly shorter (p < 0.001) and the rate of postoperative stenting was significantly lower (p = 0.002) in the D-Group. There were no significant between-group differences in intra- and post-operative complications.

CONCLUSION

The simultaneous use of two devices through a single working channel is safe and could help save the time needed to exchange the laser fiber and nitinol basket.

Rising prevalence of renal calculi: Treatments and considerations

ABSTRACT

Severe pain and urinary tract obstruction are hallmarks of renal calculi often requiring hospitalization and treatment. Renal damage can occur without proper intervention. This article discusses the role of nurses in caring for patients with renal calculi, current treatment approaches, and prevention strategies.

Outcomes of Retrograde Intrarenal Surgery Performed Under Neuraxial vs. General Anesthesia: An Updated Systematic Review and Meta-Analysis

Background

The current review aimed to assess if the outcomes of retrograde intrarenal surgery (RIRS) differ with neuraxial anesthesia (NA) or general anesthesia (GA).

Methods

The databases of PubMed, Embase, CENTRAL, ScienceDirect, and Google Scholar were searched up to 3rd December 2021 for randomized controlled trials (RCTs) and observational studies comparing outcomes of RIRS with NA or GA.

Results

Thirteen studies involving 2912 patients were included. Eight were RCTs while remaining were observational studies. Meta-analysis revealed that stone free status after RIRS did not differ with NA or GA (OR: 0.99 95% CI: 0.77, 1.26 I2 = 10% p = 0.91). Similarly, there was no difference in operation time (MD: -0.35 95% CI: -4.04, 3.34 I2 = 89% p = 0.85), 24 h pain scores (MD: -0.36 95% CI: -0.96, 0.23 I2 = 95% p = 0.23), length of hospital stay (MD: 0.01 95% CI: -0.06, 0.08 I2 = 35% p = 0.78), Clavien-Dindo grade I (OR: 0.74 95% CI: 0.52, 1.06 I2 = 13% p = 0.10), grade II (OR: 0.70 95% CI: 0.45, 1.07 I2 = 0% p = 0.10) and grade III/IV complication rates (OR: 0.78 95% CI: 0.45, 1.35 I2 = 0% p = 0.37) between NA and GA. Except for grade I complications, the results did not change on subgroup analysis based on study type and NA type.

Conclusion

Our results suggest that NA can be an alternative to GA for RIRS. There seem to be no difference in the stone-free rates, operation time, 24-h pain scores, complication rates, and length of hospital stay between NA and GA for RIRS. Considering the economic benefits, the use of NA may be preferred over GA while taking into account patient willingness, baseline patient characteristics, and stone burden.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42021295407.

RISK OF OCCURRENCE AND WAYS TO IMPROVE THE TREATMENT OF UROLITHIASIS IN PATIENTS WITH A SINGLE KIDNEY

OBJECTIVE

The aim: To summarize the state of the problem of urolithiasis in patients with a single kidney and consider current views on improving its treatment based on the analysis of world literature.

PATIENTS AND METHODS

Materials and methods: The study conducted a thorough analysis of modern scientific literature sources in the international scientometric database, which highlighted the development of urolithiasis in patients with a single kidney and the peculiarities of its treatment. The main ways to improve treatment are identified. A critical assessment of the achievements and shortcomings of various surgical treatments. The authors' own developments are presented in the article.

CONCLUSION

Conclusions: The topographic position of the kidney in the retroperitoneal space affects not only the occurrence of pathological processes in the kidney, but also the surgical strategy in the treatment of nephrolithiasis. Percutaneous nephrolithotomy is the main treatment for large (> 2 cm) or complex kidney stones. Patients with a single kidney are more prone to bleeding with PCNL treatment than patients with bilateral kidneys because they have an increased thickness of the renal parenchyma as a result of compensatory hypertrophy. RIRS is a reliable choice for patients with a single kidney who is contraindicated in PCNL.

Comparison Between Single-Use Flexible Ureteroscope and Reusable Flexible Ureteroscope for Upper Urinary Calculi: A Systematic Review and Meta-Analysis

Objective: This article explores the differences in the effectiveness and safety of the treatment of the upper urinary calculi between single-use flexible ureteroscope (su-fURS) and reusable flexible ureteroscope (ru-fURS).

Methods: We systematically searched PubMed, Embase, Cochrane Library, Scopus database, and CNKI databases within a period from the date of database establishment to November 2020. Stata 16 was used for calculation and statistical analyses.

Results: A total of 1,020 patients were included in the seven studies. The statistical differences were only found in the Clavien–Dindo grade II postoperative complication [odds ratio (OR) 0.47; 95% CI 0.23–0.98; p = 0.04]. No significant statistical differences were observed in operative time (OT), estimated blood loss (EBL), length of hospital stay (LOS), and stone-free rate (SFR).

Conclusion: Our meta-analysis results demonstrate that su-fURS, compared with ru-fURS, has similar effectiveness and better security for treating upper urinary calculi.

Learning retrograde intrarenal surgery as a sheathless and radiation-free technique

The aim of this study was to evaluate the learning curve of inexperienced surgeon who can perform the operation on their own for access sheatless and radiation-free retrograde intrarenal surgery (RIRS) technique. Results of 70 consecutive patients who have renal stones and underwent RIRS which performed by a single surgeon were evaluated retrospectively. Cumulative stone free rates and fragmentation efficacy were taken as the primary outcomes for the learning curve analyses. Stone free rate was 74% (52/70). The learning curve constructed with moving average of cumulative stone free rates showed that learning curve of sheathless RIRS consisted of three phases; rapid ascent (0-15: phase 1), slight decline (16-35: phase 2) and plateau (36-70: phase 3). The number of case needed to obtain a final plateau in stone free rates was about 35. Fragmentation efficacy reached a plateau after 50 cases. The learning curve of access sheatless and radiation-free RIRS reached plateau phase after 35-50 cases. This steep learning curve points out that surgeons do not need to experience the classical RIRS technique before starting to perform access sheatless and radiation-free technique.