Flexible Ureteroscopy Research Articles

PERCUTANEOUS APPROACH TO THE KIDNEY: SIMILARITIES AND DIFFERENCES OF VARIOUS TECHNIQUES - EXPERIENCE IN OSIJEK UNIVERSITY HOSPITAL CENTER.

Today, percutaneous nephrolithotomy (PCNL) is a standard procedure in the treatment of large kidney stones. Development of the procedure began in 1976 with publication of the first reports, while turning point came in 1985 when the first 250 cases were described. Subsequently, PCNL has become standard in the treatment of kidney stones instead of open surgery. Numerous modifications of the procedure have been developed with advancement of modern technology. Nevertheless, there is still the necessity for clearer understanding of differences and circumstances of choice among different techniques. There are significant differences in the instruments used for the procedure, so we distinguish standard PCNL (working channel of 24-30 Fr), mini PCNL (working channel of 11-18 Fr), ultra-mini PCNL (working channel <15 Fr), and micro PCNL (working channel <6 Fr). With the development of flexible ureteroscopy (FURS), a combined method is also being developed, i.e., Endoscopic Combined IntraRenal Surgery (ECIRS, PCNL + FURS). Furthermore, each procedure can be performed in prone or supine position. The aim of this paper is to point out the similarities and differences, the advantages and disadvantages of different techniques, with an additional aim to present our experience and current standard practice in kidney stone treatment.

Temperature effect of Moses™ 2.0 during flexible ureteroscopy: an in vitro assessment.

One of the main issues related to the use of high-power lasers is the associated rise in temperature. The aim of this study was to characterize temperature variations with activation of the Moses™ 2.0 laser. An in vitro experimental study was designed using a high-fidelity uretero-nephroscope simulation model to assess changes in temperature during intracorporeal laser lithotripsy. Renal and ureteral temperature records were obtained from the treatment of BegoStones positioned in the renal pelvis. Different laser settings over three time periods and two possible irrigation flow speeds were evaluated. We considered 43°C as the threshold since it is associated with denaturation of proteins. The Wilcoxon-Mann-Whitney test was used to assess quantitative variables and the Kruskal-Wallis test for categorical variables. The highest increase in intrarenal temperature was reached with 30 seconds of laser activation at a laser setting of 0.5 J/100 Hz (50 W) and a flow of 10 mL/min. Only 15 seconds of activation was sufficient for most settings to exceed 43°C. The ureteral temperature did not increase significantly, regardless of the combination of laser setting, time, or irrigation flow, except when 30 W was used for a 30 second period. Multivariate analysis showed that an irrigation flow of 20 mL/min produced an intrarenal temperature decrease of 4.7-9.2°C (p <0.001). Use of high-power lasers, both for the ureter and kidney, should involve consideration of temperature increases evidenced in this study, due to the potential biological risk entailed.

Use of artificial intelligence for sepsis risk prediction after flexible ureteroscopy: a systematic review

RESUMO Introdução: a ureteroscopia flexível é uma técnica cirúrgica minimamente invasiva utilizada para o tratamento de litíase renal. A urosepse pós-operatória é uma complicação rara, mas potencialmente fatal. Os modelos tradicionais utilizados para prever o risco dessa condição apresentam precisão limitada, enquanto modelos baseados em inteligência artificial são mais promissores. O objetivo desse estudo é realizar uma revisão sistemática a respeito do uso de inteligência artificial para detecção do risco de sepse em pacientes com litíase renal submetidos à ureteroscopia flexível. Métodos: a revisão de literatura está de acordo com o Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). A busca com palavras-chave foi realizada no MEDLINE, Embase, Web of Science e Scopus e resultou no total de 2.496 artigos, dos quais 2 se enquadraram nos critérios de inclusão. Resultados: os dois estudos utilizaram modelos de inteligência artificial para predizer o risco de sepse após utereroscopia flexível. O primeiro teve uma amostra de 114 pacientes e foi baseado em parâmetros clínicos e laboratoriais. O segundo teve uma amostra inicial de 132 pacientes e foi baseado em imagens de tomografia computadorizada no pré-operatório. Ambos obtiveram boas medidas de Area Under the Curve (AUC), sensibilidade e especificidade, demonstrando boa performance. Conclusão: a inteligência artificial fornece múltiplas estratégias eficazes para estratificação do risco de sepse em pacientes submetidos a procedimentos urológicos para litíase renal, ainda que mais estudos sejam necessários.

High-power laser lithotripsy - do we treat or harm? Histological evaluation of temperature effects in an in vivo study with thulium fiber laser.

The aim of this study was to evaluate the possible histopathological alterations that occur in the kidneys due to a continuous temperature increase above 43°C for one hour of lithotripsy using a newly introduced thulium fiber laser (TFL). Two female pigs were used. After the insertion of a 9.5/11.5 ureteral access sheath, flexible ureteroscopy and laser lithotripsy for one hour were conducted. A TFL laser with a 200-μm fiber was used. The power setting used was 8 W (0.5 J × 16 Hz). A K-type thermocouple was inserted and fixed in the upper calyx of the right porcine kidney to record the temperature in the pelvicalyceal system during the laser activation. Second-look flexible nephroscopy followed by nephrectomy and pathohistological evaluation of the operated kidney was performed one week after the procedure in the first pig and 2 weeks after the surgery in the second pig. Flexible nephroscopy did not reveal significant differences between the 2 porcine kidneys. Nevertheless, the histopathological report demonstrated severe alterations in the kidney of the first pig. Mild changes were reported in the kidney of the second pig. A significant improvement in inflammation and haemorrhagic lesions was demonstrated when comparing the 2 kidneys. The difference demonstrated between the 2 kidneys based on the histopathological report shows that the healing process is capable of improving severe to mild alterations within a one-week time frame. Two weeks after the surgery, only minor changes were observed, suggesting that even temperature increases above the threshold can be tolerated regarding renal damage.

Utilization of Flexible Ureteroscopy in Renal Stones Management in Pediatrics: Single Tertiary Center Experience.

Objectives. To assess the effectiveness and safety of flexible ureteroscopy in children treated at our center during the last 5 years. Methods. Retrospectively, we have studied 41 children that suffered 51 stone episodes, and FURS for renal calculi <2 cm. Preoperative, operative, and postoperative data were gathered. Results. The mean age of the 41 kids who experienced 51 stone episodes was 9.6 [2.8] years (4.2-16 years). The mean stone diameter was 12.8 [3.3] mm (6-20 mm). The mean operative time was 79.9 [19.9] minutes. The mean hospital stay was 27.6 [12.9] hours. The SFR after the first session was 64.7% and 80.4% after the second session. The overall complications had been recorded in 25 cases (49%) with low morbidity (Clavien grade I-III). Conclusions. Pediatric FURS is a minimally invasive option with a high SFR and a low percentage of high-grade complications in the management of pediatric renal stones.

Does the Use of an Access Sheath in Flexible Ureteroscopic Stone Surgery Affect the Stone-Free Rate in the Late Postoperative Period?

Does the Use of an Access Sheath in Flexible Ureteroscopic Stone Surgery Affect the Stone-Free Rate in the Late Postoperative Period?

Modeling and Robust Control for Tendon–Sheath Artificial Muscle System Twist With Time-Varying Parameters and Input Constraints: An Exploratory Research

Tendon–sheath artificial muscle (TSAM) is a type of artificial muscle, which is widely used in robotic flexible endoscopies. The characteristics of the tendon force/position transmission were studied recently, but the control issue of the TSAM <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"/> twist <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"/> is still barely concerned. In this article, an effective robust control scheme is proposed for the TSAM <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"/> twist <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"/> , which achieves satisfactory tracking performance. First, a rigorous model was developed for the TSAM <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"/> twist <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"/> with consideration of parameters uncertainty and actuator input constraints, moreover, the disturbance of the discontinuous friction (Coulomb friction) was analyzed. Next, by applying some signal operation methods, a nonlinear robust controller was designed. In addition, the stability of the control strategy was proven theoretically by utilizing Lyapunov-based theory. Finally, a series of hardware experiments were conducted on a robotic flexible ureteroscope test-bed. The feasibility of the proposed model, the effectiveness and robustness of the designed control method were extensively validated.

Application of Flexible Holmium Laser Sheath in Rigid Ureteroscopy for the Treatment of Impacted Upper Ureteral Stones.

By comparing with rigid ureteroscopy (r-URS), we explored the application value of flexible holmium laser sheath combined with r-URS in treating impacted upper ureteral stones. We also verified its effectiveness, safety and economy and investigated its application prospects at community or primary hospitals. From December 2018 to November 2021, 158 patients with impacted upper ureteral stones were selected from Yongchuan Hospital of Chongqing Medical University. Seventy-five patients in the control group were treated with r-URS, and 83 patients in the experimental group were treated with r-URS combined with a flexible holmium laser sheath if necessary. The operation time, postoperative hospital stay, hospitalization expenses, stone clearance rate after r-URS, auxiliary extracorporeal shock wave lithotripsy (ESWL) ratio, auxiliary flexible ureteroscope, the incidence of postoperative complications and the stone clearance rate after one month were observed. The postoperative hospital stay, stone clearance rate after r-URS, the ratio of auxiliary ESWL, the ratio of the auxiliary flexible ureteroscope, and total hospitalization expenses in the experimental group were significantly less than those in the control group (p < 0.05). There was no significant difference in operation time, postoperative complications, and stone clearance rate after one month between the two groups (p > 0.05). r-URS combined with flexible holmium laser sheath in treating impacted upper ureteral stones can improve the stone clearance rate and reduce hospitalization expenses. Therefore, it has a certain application value in community or primary hospitals.

RIRS with disposable or reusable scopes: does it make a difference? Results from the multicenter FLEXOR study.

With several single-use ureteroscopes now available, our aim was to analyze and compare data obtained globally from high-volume centers using both disposable and reusable flexible ureteroscopes and see if indeed in real-world practice either scope has a distinct advantage. Retrospective analysis was performed on the FLEXOR registry, which was created as a TOWER group (Team of Worldwide Endourological Researchers, research wing of the Endourological Society) endeavor. Patients who underwent retrograde intrarenal surgery (RIRS) for renal stones from January 2018 to August 2021 were enrolled from 20 centers globally. A total of 6663 patients whose data were available for analysis were divided into Group 1 (Reusable scopes, 4808 patients) versus Group 2 (Disposable scopes, 1855 patients). The age and gender distribution were similar in both groups. The mean stone size was 11.8 mm and 9.6 mm in Groups 2 and 1, respectively (p < 0.001). Group 2 had more patients with >2 cm stones, lower pole stones and of higher Hounsfield unit. Thulium fiber laser (TFL) was used more in Group 2 (p < 0.001). Patients in Group 2 had a slightly higher stone-free rate (SFR) (78.22%) and a lower number of residual fragments (RFs) compared with Group 1 (p < 0.001). The need for further treatments for RF and overall complications was comparable between groups. On multivariate analysis, overall complications were more likely to occur in elderly patients, larger stone size, lower pole stones, and were also more when using disposable scopes with longer operative time. RFs were significantly higher (p < 0.001) for lower pole, larger, harder, multiple stones and in elderly. Our real-world practice observations suggest that urologists choose disposable scopes for bigger, lower pole, and harder stones, and it does indeed help in improving the single-stage SFR if used correctly, with the appropriate lasers and lasing techniques in expert hands.

Systematic Review Comparing Flexible Ureteroscopy and Percutaneous Nephrolithotomy for Lower Pole Stone

Background: Lower pole renal stone treatment is remains controversial, and choosing the appropriate treatment modality has become a challengeObjective: To systematically assess the effectiveness and safety of retrograde flexible ureteroscopy (FURS) versus percutaneous nephrolithotomy (PCNL) in treating lower pole stones.Methods : A search of PubMed, Cochrane Library, ScienceDirect, Wiley Online Library, and Scopus databases to identify all studies comparing FURS and PCNL for lower pole renal stones until August 2022 was conducted. Article selection was performed through the search strategy based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.Result: A total of 10 comparative studies involving 1241 participants with lower pole calyx stone size 1.0 – 3.0 cm were included for this systematic review. Our review found out that stone free rate PCNL procedure range around 83.3% - 98.3% and FURS procedure range around 78.6% - 93.2%; operative time of PCNL procedure range around 46.2 + 24.3 to 85.5 + 41.1 minutes meanwhile FURS procedure range around 55.8 + 11.4 to 123.0 + 57.4 minutes; hospital stay of PCNL procedure range around 0.3 + 0.04 to 5.3 + 1.20 days and hospital stay of FURS procedure range around 0.16 + 0.04 to 3.2 + 0.52 days; and complications rate after PCNL procedure range around 4.4% - 25% and after FURS procedure range around 4.6% - 21.6%.Conclusion: Most of studies shown that PCNL procedure have higher stone free rate, shorter operative time, longer hospital stays and higher complications rate compared against FURS procedure.

Comparing Flexible Ureteroscopy and Percutaneous Nephrolithotomy for Lower Pole Stone

A total of 10 comparative studies involving 1241 participants with lower pole calyx stone size 1.0 – 3.0 cm were included for this systematic review. Our review found out that stone free rate PCNL procedure range around 83.3% - 98.3% and FURS procedure range around 78.6% - 93.2%; operative time of PCNL procedure range around 46.2 + 24.3 to 85.5 + 41.1 minutes meanwhile FURS procedure range around 55.8 + 11.4 to 123.0 + 57.4 minutes; hospital stay of PCNL procedure range around 0.3 + 0.04 to 5.3 + 1.20 days and hospital stay of FURS procedure range around 0.16 + 0.04 to 3.2 + 0.52 days; and complications rate after PCNL procedure range around 4.4% - 25% and after FURS procedure range around 4.6% - 21.6%. Most of studies shown that PCNL procedure have higher stone free rate, shorter operative time, longer hospital stays and higher complications rate compared against FURS procedure.

Hypoalbuminemia Within One Hour After Surgery as a Predictor of Post-Operative Urosepsis in Patients Undergoing Flexible Ureteroscopy Lithotripsy: A Retrospective Study.

Abstract Background: To investigate retrospectively whether changes in serum albumin levels within one hour of flexible ureteroscopy (fURS) lithotripsy can be used as a predictor of post-operative urosepsis. Patients and Methods: Eligible patients with unilateral upper urinary calculi who underwent fRUS lithotripsy performed by a single surgeon at our center were included in the analysis. The patients were divided into sepsis and non-sepsis groups. The change ratio of albumin and white blood cell (WBC) count was calculated by post-operative/pre-operative index*100%. Univariable and multivariable logistic regression analyses were used to assess whether there was a correlation between risk factors and post-operative urosepsis. The receiver operating characteristic (ROC) curve was used to analyze factors that showed significant differences in multivariable logistic regression analysis. Results: A total of 314 patients were included in the analysis, 20 of whom had post-operative urosepsis and five developed septic shock; no deaths occurred. Multivariable logistic regression analysis showed that urine culture results, WBC counts within one hour after surgery, post-operative albumin levels, and the degree of albumin changes after surgery were independent predictors of post-operative urosepsis. Receiver operating characteristic curve analysis showed that noteworthy hypoalbuminemia after surgery and positive pre-operative urine culture could help screen high-risk patients for post-operative urosepsis effectively. Conclusions: Hypoalbuminemia shortly after operation can be utilized as a predictor for early diagnosis of post-operative urosepsis in patients undergoing fURS lithotripsy.

Retrograde endoscopic-assisted percutaneous treatment of transplanted kidney calyceal fistula

Introduction. Calyceal fistula is a rare complication of a renal transplantation. This complication can lead to postoperative graft failure. The treatment approaches range from a partial nephrectomy to a routine nephrostomy.Objective. To present the successful application of the retrograde endoscopic-assisted percutaneous treatment of transplanted kidney calyceal fistula.Clinical case. A patient after kidney allotransplantation is under our care. Control postoperative ultrasound examination revealed a pararenal fluid mass in the left iliac region. Its percutaneous drainage was performed. Biochemical analysis revealed high levels of creatinine and urea in the drainage discharge. Despite ureteral stent and urethral catheter drainage, about 500 to 600 ml of urine per day was excreted by the drainage. Percutaneous puncture nephrostomy could not be performed due to the absence of dilatation of the renal cavity system. In the lithotomic position, the damaged calyx was identified by performing flexible ureteropyeloscopy. Then we percutaneously targeted the injured calyx and the distal end of the ureteroscope inserted transurethrally, so that the needle tip appeared in the paranephral cavity opposite the injured calyx. Under the control of a flexible ureteroscope the needle was inserted into the kidney pelvis, a nephrostomy tube 12 Ch was placed along the string. The discharge through the drain stopped within a week and it was removed. Follow-up examination nine weeks after surgery revealed that the patient had no complaints and renal ultrasound showed no features, so the nephrostomy tube was removed.Conclusion. The described method is the minimally invasive, affordable, and efficient method for the treatment of transplanted kidney calyceal fistula.

Симультанная билатеральная ретроградная интраренальная хирургия c использованием тулиевого волоконного лазера.

Introduction. Urolithiasis is a common disease and up to 15% of patients have multiple kidney stones. Retrograde intrarenal surgery (RIRS) can be used in the surgical treatment of kidney stones because this method is highly effective. Patients with multiple kidney stones often necessitate several surgeries. In this study we our own experience of bilateral RIRS to analyze its effectiveness and safety. Materials and methods. From January 2021 to February 2022 the simultaneous bilateral RIRS were performed to 11 patients (7 man and 4 woman). The maximal size of stone was 21 mm (the average size of the right kidney was 15,0 mm ± 6,0 mm and the left kidney – 11,7 mm ± 4,3 mm). Average stone density was more than 1000 HU. The mean age of the patients was 57±13 years. Bilateral retrograde intrarenal surgery was performed simultaneously by two surgeons using flexible ureteroscopes using a SuperPulsed thulium fiber laser. The following parameters were assessed: surgical intervention time; stone free rate (SFR); degree of ureteral injury according to the post-ureteroscopic lesion scale (PULS); the need for drainage of the ureter in the postoperative period, assessment of the creatinine level, glomerular filtration rate (GFR) and C-reactive protein in the postoperative period; postoperative complications according to the Clavien-Dindo classification. Results and their discussion. The average duration of the surgery was 56±11 minutes. The SFR level was 90,9 %. At the final inspection of the ureters: on the right side injury Grade 0 according to the PULS scale was recorded in 10 patients, Grade 1 – in 2 patients; on the left side Grade 0 – in 9 patients, Grade 1 – in 2 patients. The surgery was completed with the installation of ureteral catheters in 10 and 9 cases on the right and left sides, respectively. Three surgical interventions ended with the installation of ureteral stents on one side or another. The level of creatinine and C-reactive protein in the postoperative period increased on average by 10.2±5.7 μmol/l and 1.8±0.6 mg/l, respectively. The GFR decreased by 7.2 ± 2.6 ml/min. A complication was registered in 1 patient – increased body temperature on the 1st day, stopped by antibiotic therapy (Clavien-Dindo II). Conclusions. Simultaneous bilateral RIRS using single-use flexible ureteroscopes and a SuperPulsed thulium fiber laser is a safe and effective procedure for patients with bilateral nephrolithiasis.

Percutaneous Nephrolithotomy Combined Antegrade Flexible Ureteroscope for Complete Staghorn Stones: A Case Report of a New Concept of Stone Surgery

Percutaneous nephrolithotomy (PCNL) is the treatment of choice for staghorn stones. However, residual stones in calyces remain a challenge due to the limited angle which makes the approach difficult. The new operative technique of endoscopic combined intrarenal surgery (ECIRS), which integrates the advantages of PCNL and retrograde intrarenal surgery (RIRS), was developed to overcome this difficulty. However, two experienced urologists are required to perform ECIRS, and the patient has to be placed in the Galdakao-modified supine Valdivia position or modified prone split-leg position which cannot be achieved in the elderly or patients with ankylosing arthritis, as it may cause harm due to abnormal traction of the joints. In addition, it is difficult for surgeons to create an ideal access tract to perform PCNL in this position. We report the case of a 72-year-old female patient with left staghorn stone. We performed RIRS first and then placed the patient in the decubitus position for PCNL with antegrade flexible ureteroscopy. This method allows patients to be placed in an easier position, with the use of flexible ureteroscopy through a nephroscope to find previously unreachable stones. Moreover, in addition to the more comfortable position both for surgeons and patients, this procedure can also deal with large complex renal stones as with ECIRS. We also created a brand-new definition for stone clearance rate, namely, stone reduction efficiency (SRE). There was a high stone reduction efficiency of 12.64 (mm2/min) in our patient, and no complications occurred. We suggest that this procedure is an ideal alternative treatment for a huge staghorn stone instead of PCNL or ECIRS.

An ORB-SLAM3-based Approach for Surgical Navigation in Ureteroscopy

ABSTRACT In ureteroscopy a flexible ureteroscope is used to inspect the kidneys and the ureters. In this context, we investigate robotic solutions that leverage recent developments from Simultaneous Localization and Mapping (SLAM) to provide a 3D map of the organ to be explored and the ureteroscope’s pose. With this aid, the surgeoncan navigate through the organ more precisely. Additionally, for the final organ inspection, the risk of missing certain regions of the organ is minimized. In this paper, we propose a visual, monocular SLAM system based on ORB-SLAM3 that is able to estimate the pose of the ureteroscope’s tip. In order to fulfill this task, we introduce two pre-processing steps. The first one aims at increasing the contrast of the image and the second one helps to avoid detecting features in non-desired regions (e.g. reflections). Additionally, we extend ORB-SLAM3 with A-KAZE and SuperPoint features and compare their performances to ORB features. The proposed method is evaluated in two experiments. The first experiment shows that we are able to estimate the trajectory of the ureteroscope and the map of a synthetic kidney with low errors. The second experiment shows that the method also gives promising results in cystoscopy.

Determinants of outflow rate through the ureteral access sheath during flexible ureteroscopy: an experimental in vivo study in an anesthetized porcine model.

To evaluate the effect of different ureteroscope positions, saline pumping frequency, laser fiber diameter and ureteral access sheath (UAS) on outflow rate during flexible ureteroscopy (fURS). This study was performed in an anesthetized porcine model. The fURS setup included a manual pumping system, a 9.5Fr single used-digital flexible ureteroscope and a ureteral access sheath (UAS). Outflow was collected and measured from the UAS during 1min in all experimental settings. The evaluated variables were the position of the ureteroscope, the pumping frequency (2s, 3s or 5s), the diameter of the used UAS (12/14Fr or 14/16Fr) and laser fiber (200μm or a 272μm). Ureteroscope position in the lower calyx was associated with significantly lower outflow rate (p < 0.05). The use of the 14/16Fr UAS resulted in improved flow in the renal pelvis and upper calyx (p < 0.05) but not in the lower calyx. The use of a 200μm laser fiber only improved flow in the upper calyx and when a 14/16Fr UAS was being used. Pumping frequency did not show a significant correlation with outflow rate. The ureteroscope positioning and UAS size were important determinants of outflow rate through the UAS during fURS, while laser fiber diameter had a limited effect. In the lower calyx the outflow was minimal and was not improved by using a larger UAS.

Super-Mini Percutaneous Nephrolithotomy for Nephrolithiasis: A Systematic Review and Meta-Analysis.

We aimed to conduct a systematic review and meta-analysis to summarize the current evidence regarding the role of super-mini percutaneous nephrolithotomy (SMP), whichrefers to a 7-Fr nephroscope placed through a tract sized 10-14 Fr, in treating renal stones and compare its outcomes with the standard mini-percutaneous nephrolithotomy (PCNL) techniques. A systematic literature search was conducted on the Medline database via PubMed and SCOPUS until May 2022 to retrieve the relevant studies. The titles and abstracts of unique records were screened for eligibility, followed by the full-text screening of potentially eligible abstracts. Data extraction was performed by two independent reviewers. The risk of bias assessment was conducted based on the study design. Open Meta (Analyst) and Review Manager 5.4 were used to perform all analyses. A total of 14 studies (n = 4,323 patients) were included, with two randomized controlled trials, one single-arm trial, and 11 cohort studies. The stone-free rate (SFR) of SMP was 91.4%. The pooled analysis showed no significant difference between SFR in mini-PCNL (mean difference (MD) = 1.03, 95% confidence interval (CI) = (0.99, 1.06), p = 0.12) and flexible ureteroscopy (MD = 0.84, 95% CI = (0.4, 1.76), p = 0.65]. On the other hand, SMP had a better SFR rate when compared with retrograde intrarenal surgery (MD = 1.3, 95% CI = (1.01, 1.66), p = 0.04). The pooled mean operative time of SMP was 49.44 minutes (95% CI = (41, 57.88), p < 0.001), which was longer than mini-PCNL (MD = 1.92, p < 0.001) and shorter than ureteroscopy (MD = -17.17, p < 0.00001). In the SMP group, the postoperative complications included fever (>38°C), pain, and hematuria, with an incidence of 7.6%, 2.3%, and 3.4%, respectively. The mean length of hospital stay after SMP was 2.4 days (95% CI = (2.17, 2.7), p < 0.001). The current evidence suggests that SMP is a safe and effective technique in the management of renal stones in both children and adults.

Outcomes of Ureteral Stent Removal by Flexible Cystoscope Versus Semirigid Ureteroscope: A Prospective Randomized Clinical Trial

Outcomes of Ureteral Stent Removal by Flexible Cystoscope Versus Semirigid Ureteroscope: A Prospective Randomized Clinical Trial

The regular use of calcium channel blockers before flexible URS appears to facilitate primary UAS insertion: a retrospective study in a single center.

To evaluate the effect of regular use of CCB before flexible URS for successful primary UAS insertion. We retrospectively analyzed 209 patients who underwent flexible ureteroscopy (URS) for upper urinary tract calculi between Jan 2021 and Dec 2021. Patients were divided into two groups based on whether calcium channel blockers (CCB) were used (n = 72) or not (n = 137). The following parameters were collected: age, sex, height and weight, BMI, stone location, stone burden, number of stones, operation time, hospital stay, hospital readmission, post-operative fever, post-operative SIRS rate, Clavien-Dindo grade, hospitalization costs, successful primary UAS insertion. We compared the two groups using Student's t test, Mann-Whitney U test and χ2 test for quantitative and categorical variables, respectively. A logistic regression model was used to identify predictive factors of UAS successful primary insertion. Compared with the non-CCB group, the CCB group had a higher successful primary UAS insertion rate (97.2% vs.85.4%, p = 0.008), and a lower hospital readmission rate (2.8% vs.12.4%, p = 0.021). In multivariate analyses, the regular use of CCB was the only predictive factor of successful primary UAS insertion rate (OR 6.32, 95% CI 1.41-28.29, p = 0.016). The regular use of calcium channel blockers (CCB) before flexible URS appears to facilitate ureteral access sheaths (UAS) primary insertion.