Retrograde Intrarenal Surgery Procedure Research Articles

Urinary Tract Infection Predictors in Patients Undergoing Retrograde IntraRenal Surgery for Renal Stones: Does the Instrument Make the Difference?

Background: Retrograde intrarenal surgery (RIRS) using flexible ureterorenoscopes is a cornerstone approach for renal stone removal, yet it carries a significant risk of postoperative urinary tract infection (UTI). With the emergence of single-use ureterorenoscopes, there is growing interest in their potential to mitigate this risk. This study aimed to compare the postoperative infection rates between single-use and multi-use ureterorenoscopes in RIRS procedures and to identify predictors of postoperative UTI. Methods: Data were collected from 112 consecutive patients who underwent RIRS for renal stones between March 2022 and September 2023. Peri-operative variables including age, gender, body mass index (BMI), stone size, stone location, type of ureterorenoscope, Hounsfield Units (HU), pre-operative hydronephrosis, laboratory analysis, and operative time were evaluated. Univariate and multivariate logistic regression analyses were performed to assess the predictors of postoperative UTI. Results: Of the cohort, 77 surgeries (68.7%) utilized multi-use ureterorenoscopes, while 35 (31.3%) utilized single-use devices. Stone diameter, number of stones, type of ureterorenoscope, and operative time were significant predictors of postoperative UTI in the univariate analysis. Multivariable logistic regression showed that operative time (OR, 1.3; 95% CI, 0.55-0.99; p = 0.03) and type of ureterorenoscope (multi-use vs. single-use) (OR, 1.14; 95% CI, 1.08-1.2; p < 0.001) were independent predictors of postoperative UTI. Conclusions: In conclusion, this study highlights that multi-use ureterorenoscopes and prolonged operative time are associated with an increased risk of postoperative UTI in RIRS procedures. Careful pre-operative evaluation and meticulous patient selection are essential to minimize the occurrence of postoperative UTIs and optimize patient outcomes in RIRS for renal stones.

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

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. 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 10-30mm. 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. 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 25.12mL/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. Learning curve analysis for the three newbie surgeons indicated that approximately 12-15 cases were required to reach a plateau.

Risk factors of stone residual after retrograde intrarenal surgery: A prospective cohort study.

Complete removal of renal stones is crucial for optimal patient outcomes, but recent studies have reported residual stones after retrograde intrarenal surgery (RIRS). This study aimed to identify the associated risk factors to improve patient management and treatment selection. This cohort study was conducted over 18 months at two hospitals and recruited adult patients with renal stones less than 3 cm. Preoperative assessment included medical history, physical examination, laboratory tests, and radiological imaging. Intraoperative and postoperative data collection and follow-up were conducted to evaluate surgical success and potential complications. A total of 100 patients were included, with a mean age of 45.3 ± 10.7 years and a mean BMI of 26.2 ± 1.4 kg/m2. Approximately 19% of the patients had residual stones after the RIRS procedure. The RUSS score showed good diagnostic performance with an AUC of 0.843, and the optimal cut point was ⩾2.0 with a sensitivity of 52.6% and specificity of 95.1%. Independent predictors of residual stones were multiple sites (OR = 24.98; p = 0.002), multiple stones (OR = 13.62, p = 0.002), stone size of 21-30 mm (OR = 4.91, p = 0.038), lower calyx site (OR = 4.85, p = 0.033), and surgeon experience of fewer than 50 cases (OR = 6.82, p = 0.020). This study identifies several factors associated with residual stones after RIRS for renal stones, including stone size, location, number, and surgeon experience. The study suggests that the RUSS score can be used as a reliable tool for predicting the likelihood of residual stones, which can help clinicians in patient selection and treatment planning.

Retrograde intrarenal surgery using the ILY robotic flexible ureteroscope: a single centre experience.

The ILY robotic flexible ureteroscope has been introduced in order to improve intraoperative ergonomics, reduce operator distance from radiation and shorten the learning curve. In this study we aimed to assess the clinical performance and feasibility of the ILY robot during retrograde intrarenal surgery (RIRS) and combined endoscopic procedures (miniECIRS). The RIRS procedures were performed using the ILY robotic arm in 57 adult patients (46 RIRS and 11 miniECIRS) from 2022 to 2023. All procedures were performed in the supine position. Pre-stenting was not the standard of care. Turning on and calibration of the device took approximately 100 s. Average draping time was 93 s using original ILY drapes and 47 s using classic drapes designed for C-arm covering. Mean docking time was 73 s in procedures with ureteral access sheath (UAS) and 61 s in procedures without it. The undocking took less than 60 s in every case. Average procedure time was 63 min for RIRS and 55 min for miniECIRS. Endoscopically proven stone-free rate was achieved in 37 (80.4%) RIRS and 10 (90.9%) miniECIRS patients. A total of 17 (36.9%) RIRS and 8 (72.7%) miniECIRS procedures required conversion in order to perform basketing and stone fragments retrieval/transposition. The use of ILY robot during endourological procedures is feasible and urologists that are familiar with the device controller do not require extensive training. The time needed for device draping, docking and undocking was approximately 4 minutes. Moreover, use of the robot resulted in satisfactory stone-free rates.

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.

Comparison of Understanding and Recall of Informed Consent Information in Written and Video Formats: A Focus on Retrograde Intrarenal Surgery

Objective: The aim of this study was to assess the impact of using video as an educational tool in the informed consent process for retrograde intrarenal surgery (RIRS) on patient understanding, satisfaction, and preferences compared to traditional written consent forms. Material and Methods: A total of 114 patients scheduled for RIRS participated in this study. After reading informed consent, participants completed a questionnaire assessing their baseline knowledge about the RIRS procedure. They then watched an educational video about the procedure and completed a post-video questionnaire to assess changes in knowledge and preferences between written and video-based informed consent. Results: The results demonstrated that incorporating a video into the informed consent process led to significant improvements in patients’ knowledge about the RIRS procedure (p&amp;lt;0.001). A majority of participants (94.5%) found the video presentation to be more helpful than the written consent form and preferred it over the traditional method. Additionally, the use of video was associated with increased confidence in making informed decisions about the procedure. The majority of participants found the video to be easily accessible and comprehensible, which contributed to their overall satisfaction. Conclusion: Video-enhanced informed consent process can be a valuable addition to the standard informed consent process in clinical practice. By providing easily accessible and comprehensible information, healthcare providers can better meet patients’ needs and improve the overall quality of care. This approach may lead to better patient outcomes, increased trust in healthcare providers, and a more patient-centered approach to medical care.

The evaluation of morphology of renal pelvicalyceal system's and infundibulopelvic anatomy of kidney's lower pole in post-mortem series.

Urinary system stones are frequently encountered in the community. Together with technological developments, introduction of new treatment procedures such as extracorporeal shock wave lithotripsy, percutaneous nephrolithotomy and retrograde intrarenal surgery has further reduced morbidity, mortality and hospitalisation time of patients. In order to maximise success and to reduce complications of these procedures, it is necessary to evaluate anatomy and morphological differences of kidney collector system before the procedure. This study was conducted for the purpose of determining the morphology of the kidney collector system and the negative anatomic factors of the lower pole in autopsy cases performed in our institution. Eighty two kidney units obtained from 41 autopsy cases conducted in Faculty of Medicine Department of Forensic Medicine, Sivas Cumhuriyet University between September 2017 and September 2018 were included in the study. Percentages were found as 78% for intrarenal pelvis, 13.4% for borderline pelvis, 6.1% for extrarenal pelvis and 2.4% for pelvic nonexistence. When pelvicalyceal anatomy was evaluated, percentages were found as 32.9% for bicalyceal, 26.8% for tricalyceal, 20.7% for multicalyceal, and 19.5% for unclassified calyceality. When it was evaluated according to opening of calyces into the renal pelvis based on Sampaio classification, percentages were found as 30.5% for AI, 17.1% for type II, 28% for BI, 18.3% for BII, and 6.1% for unevaluated part. Infundibular lengths of kidney's lower pole were detected as under 3 cm in 39% and over 3 cm in 61% of all cases. Infundibulopelvic angles of kidney's lower pole were measured as under 70o in 42.7% and over 70o in 57.3% of all cases. In our study, there was no statistically significant difference between the right and left kidneys in terms of collecting system morphology and lower pole's negative anatomical factors. Only infundibular length which is one of the collecting system morphology and lower pole's negative anatomical factors were statistically shorter in females than males. There was no difference in terms of other parameters. In conclusion, the findings of this study are largely consistent with the results of similar studies. This reveals that renal collecting system morphology and negative anatomic factors in the lower pole collecting system in human are roughly similar. In clinical practice, pre-treatment computed tomography and, if necessary, magnetic resonance urography evaluation of the lower pole negative anatomic factors may contribute to gain preliminary information about both the clearance of stone fragments especially after shock wave lithotripsy and retrograde intrarenal surgery procedures and perioperative complications proactively.

The effects of stone density on surgical outcomes of retrograde intrarenal stone surgery.

Several pre-operative parameters have been studied to estimate stone-free rate (SFR) following retrograde intrarenal surgery (RIRS) procedures. The objective of this study was to evaluate the effects of stone density on surgical outcomes of RIRS. This retrospective study included 30 stone-free patients (Group SF) and 30 patients with residual fragments (Group RF). Patients' age and gender, laterality, non-contrast CT findings, including size and density of the kidney stones, infundibular pelvic angle (IPA), operational time, and post-operative pain were recorded and compared between the two groups. The stone density was measured by free hand region of interest (ROI) determination coincident with the stone borders and expressed as Hounsfield units (HUs). The rate of single stones was significantly higher in Group SF compared to Group RF (p < 0.001). The mean stone size was found as 11.93 ± 7.81 mm in Group SF and 16.27 ± 7.29 mm in Group RF with the difference being statistically significant (p < 0.001). The mean IPA was 53.87 degrees in Group SF and 50.33 degrees in Group RF. The mean density was measured as 748.17 ± 318.14 HU in Group SF and 945.90 ± 345.30 HU in Group RF. The mean stone density was statistically significantly higher in patients with residual fragments compared to the stone-free patients (p < 0.001). This study revealed that stone density as measured as HU affects the treatment outcomes with RIRS procedure and the mean density is significantly higher in patients with residual stone fragments. Studies about the effects of HUs on stone-free rate are limited in the literature. Stone density affects the treatment outcomes with RIRS procedure and the mean density is significantly higher in patients with residual stone fragments.

Analysis of clinical factors associated with intraoperative and postoperative complications of retrograde intrarenal surgery.

The aim of this study was to evaluate the factors affecting intraoperative and postoperative complications in retrograde intrarenal surgery. In this retrospective cohort study, 706 retrograde intrarenal surgery procedures administered to 617 patients were reviewed. Intraoperative and postoperative complications were classified according to the modified Satava and modified Clavien classification systems. The stone-free rate was 407 (57.6%) and the success rate was 528 (74.8%). Intraoperative complications were observed in 215 (30.5%) patients. The most common intraoperative complication was mild bleeding 60(8.5%), while the only independent risk factor associated with intraoperative complications was the presence of residual stones. Postoperative complications were observed in 190 (26.9%) patients. The most common postoperative complication was fever requiring antipyretic drugs 60(8.6%), while independent risk factors associated with postoperative complications were the presence of residual stones and solitary kidney.

P0175DETERMINANTS OF RENAL PAPILLARY APPEARANCE IN RENAL STONE FORMERS: AN IN-DEPTH EXAMINATION

Abstract Background and Aims Nephrolithiasis is a medical condition characterized by high prevalence among the general population both in Europe and in the U.S. and it is responsible for high costs reaching up to $10 billion per year. It is associated with specific comorbidities such as obesity, arterial hypertension, diabetes mellitus, metabolic syndrome and chronic kidney disease. Kidney stones development is believed to start either from Randall’s plaques or from stone plugs. Both these lesions can be seen on renal papillary surfaces, but what promotes the formation of plaques and plugs is not entirely understood. The aim of this study is to investigate the association between the urinary metabolic milieu and a published endoscopic papillary evaluation score (PPLA). We also evaluated the correlation of PPLA score with kidney stone recurrence during follow-up. Method We prospectively enrolled 31 stone forming patients who undergone retrograde intrarenal surgery procedures. Visual inspection of the accessible renal papillae was performed in order to calculate the PPLA score based on the appearance of ductal plugging, surface pitting, loss of papillary contour and Randall’s plaque extension. Demographic information, blood samples, 24h urine collections and kidney stone events during follow-up were collected. Stone composition was analyzed using infrared-spectroscopy. Relative urinary supersaturations (RSS) for calcium oxalate (CaOx), calcium phosphate (CaPi) and uric acid (UA) were calculated using the Equil2 software. PPLA score &amp;gt; 3 was defined as high. Results Median follow-up period was 11 (min/max 5, 34) months. PPLA score was inversely correlated with BMI (rho = −0.39, p = 0.035) and history of recurrent kidney stones (median PPLA 5.0 vs 2.5, p = 0.029), these results were confirmed when PPLA was considered as a categorical variable (median BMI 27 vs 24, recurrent stone disease 12 vs 62%, p= 0.006). Furthermore, high PPLA score was associated with lower odds of new kidney stone events during follow-up (OR 0.154, 95% confidence interval 0.024, 0.998, p = 0.05). No significant correlations were found between PPLA score, stone composition, blood parameters, 24h urine solute excretions and RSS for CaOx, CaPi and UA. Conclusion Different papillary abnormalities seem to be linked to specific mechanisms of stone formation. Although data regarding PPLA score are inconsistent, it may be a valid asset for both medical and surgical management of nephrolithiasis. Larger, long-term prospective clinical studies need to be conducted to assess the validity of PPLA score system in evaluating risk of stone recurrence.

Retrograde intrarenal surgery of renal stones: a critical multi-aspect evaluation of the outcomes by the Turkish Academy of Urology Prospective Study Group (ACUP Study).

To outline and evaluate the incidence, management and follow-up of the residual fragments (RFs) following retrograde intrarenal surgery (RIRS) of renal stones by the Turkish Academy of Urology Prospective Study Group (ACUP Study). Following the ethical committee approval, 15 centers providing data regarding the incidence, management, and follow-up of RFs after RIRS were included and all relevant information was recorded into the same electronic database program ( https://acup.uroturk.org.tr/ ) created by Turkish Urology Academy for Residual Stone Study. A total of 1112 cases underwent RIRS for renal calculi and RFs were observed in 276 cases (24.8%). Of all the parameters evaluated, our results demonstrated no statistically significant relation between preoperative DJ stenting and the presence of RFs (χ2 (1) = 158.418; p = 0.099). RFs were significantly higher in patients treated with UAS (82 patients, 29.3%) during the procedure compared to the cases who did not receive UAS (194 patients, 23.3%) (χ2 (1) = 3.999; p = 0.046). The mean period for a secondary intervention after RIRS was 28.39 (± 12.52) days. Regarding the procedures applied for RF removal, re-RIRS was the most commonly performed approach (56%). Despite the reported safe and successful outcomes, the incidence of RFs is higher, after the RIRS procedure particularly in cases with relatively larger calculi. Such cases need to be followed in a close manner and although a second flexible ureteroscopy is the treatment of choice for fragment removal in the majority of these patients, shock wave lithotripsy and percutaneous nephrolithotomy may also be preferred in selected cases.

Regional vs General Anesthesia for Retrograde Intrarenal Surgery: A Systematic Review and Meta-Analysis.

Purpose: To determine the effectiveness and safety of retrograde intrarenal surgery (RIRS) under regional anesthesia (RA) vs general anesthesia (GA). Methods: In February 2020, a comprehensive search of PubMed, EMBASE, Web of Science, Cochrane Library, ClinicalTrials.gov, and WHO International Clinical Trials Registry was performed to find eligible studies comparing outcomes of GA and RA during RIRS procedure. Result parameters, including stone-free rate (SFR), operation time, postoperative length of stay, postoperative first-day visual analog scale (VAS) score, and complication rates were assessed using RevMan 5.3. Results: Six studies (five randomized controlled trials and one retrospective study) with 1747 individuals were included. Pooled results revealed no statistical difference exist concerning SFR (odds ratio [OR] = 1.07, p = 0.63), postoperative length of stay (weighted mean difference [MD] = 0.08, p = 0.54), postoperative first-day VAS score (MD = -0.10, p = 0.23), and complication rates (OR = 0.91, p = 0.46). However, the RA group had shorter operation time (MD = -5.41, p < 0.00001) compared with GA group. Conclusion: The present study showed that RA demonstrated shorter operation time than GA, and was similar to GA regarding SFR, postoperative length of stay, postoperative first-day VAS score, and complication rates. We considered that RA might be a better alternative with prudent patient selection.

The effect of ureterorenoscopy and retrograde intrarenal surgery procedures on renovascular hemodynamics

The effect of ureterorenoscopy and retrograde intrarenal surgery procedures on renovascular hemodynamics

Retrograde intrarenal surgery technique without using fluoroscopy and access sheet in the treatment of kidney stones

Background/aim In this study, we aimed to present our results on single-guidewire flexible ureteroscopy and retrograde intrarenal surgery without fluoroscopy and an access sheet, and to evaluate the efficacy and safety of this procedure retrospectively.Material and methodsOur routine technique can be described as the evaluation of the ureter using a semirigid ureterorenoscope (URS), leading in the guidewire through the semirigid URS, pulling the semirigid URS back, inserting the flexible URS with the aid of the guidewire, inserting the laser probe through the flexible URS, and performing laser lithotripsy. Results Our study included 400 male and 198 female patients with a mean age of 36.8 ± 16 (14–80) years. The mean stone size was 8.7 ± 4 (8–20) mm, and the mean operation time was 56 (32–106) min. Postoperative fever was observed in 24 (4%) of the patients, and 30 (5%) patients had hematuria as a minor complication. A stone-free status was observed in 466 (78%) patients, while 102 (17%) patients had clinically insignificant minor stone fragments and 30 patients had clinically significant stone residue. Conclusion The retrograde intrarenal surgery procedure using only a guidewire without fluoroscopy and an access sheet in the treatment of kidney stones is technically safe and effective.

Infectious Complications After Laser Vaporization of Urinary Stones During Retrograde Intrarenal Surgery Are Not Associated with Spreading of Bacteria into Irrigation Fluid but with Previous Use of Fluoroquinolones

BackgroundThe pathogenesis of infectious complications after retrograde intrarenal surgery (RIRS) is not fully understood. ObjectiveTo evaluate spreading of bacteria into irrigation fluid and blood during RIRS for stone management and to correlate such spreading with infectious complications. Design, setting, and participantsFrom January to December 2017, 38 patients who underwent RIRS for stones in two urological units were enrolled in this prospective, longitudinal cohort study. InterventionA urine culture was taken before surgery and antimicrobial prophylaxis was given in line with the European Association of Urology guidelines. Blood and irrigation fluid samples were collected at the start of the endoscopic procedure and every 30min during the procedure. All samples were microbiologically examined and findings were compared with clinical data. Outcome measurements and statistical analysesSymptomatic and asymptomatic urinary tract infectious complications were correlated with microbiological and clinical data, using Student t test or Mann–Whitney U test. Results and limitationsTen patients showed significant bacterial growth in irrigation fluid samples (seven Escherichia coli, two Klebsiella pneumoniae, and one Pseudomonas aeruginosa). Eight patients (21%) got febrile urinary tract infections during hospital stay: two had bacterial growth in the irrigation fluid (25%) and one also had bacteremia (12.5%). No correlation was found either between the bacterial growth in the irrigation fluid samples and the urine cultures that were taken before the procedure, or between the bacterial growth in the irrigation fluid samples and the development of postoperative infectious complications. Previous use of fluoroquinolones and a history of urinary tract infections were associated with infectious complications after RIRS. ConclusionsWe demonstrated spreading of bacteria into the irrigation fluid during RIRS procedures, but this spreading was not associated with the development of infectious complications. Particular attention should be given to previous antibiotic treatment before administration of antimicrobial prophylaxis. Patient summaryBacterial spreading into irrigation fluid is a common finding during retrograde intrarenal surgery, but it is not associated with infectious complications after the procedure. Particular attention should be given to previous antibiotic treatment before administration of antimicrobial prophylaxis.

Retrograde intrarenal surgery and percutaneous nephrolithotomy for the treatment of stones in horseshoe kidney; what are the advantages and disadvantages compared to each other?

IntroductionKidney stones occur more frequently in patients with a horseshoe kidney (HSK) anomaly. Abnormal anatomy may make the stone removal procedures more difficult. Therefore we aimed to evaluate and compare retrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PCNL) for the treatment of renal stones in the HSK anomaly.Material and methodsIn this descriptive study, patients with HSK anomaly who underwent RIRS and PCNL procedures were retrospectively evaluated. Demographic and renal stone characteristics, success and complications associated with the surgical methods were compared across patients.ResultsA total of 49 patients were evaluated, 28 underwent RIRS and 21 underwent PCNL. No differences were determined between the groups concerning the demographics of patients and stone characteristics. A single session and final stone-free rate was 71.4% and 85.7% in RIRS, 81% and 90.5% in PCNL (both p ≥0.05). However, RIRS had more re-treatment rate, while its mean length of hospital stay was shorter than PCNL (p = 0.035, p = 0.001). While no differences were detected between the associated complication rates, more of the complications encountered in the PCNL group were of a serious nature.ConclusionsIn the HSK anomaly, renal stones can be treated with RIRS and PCNL procedures with high success. With its minimal morbidity, low complication rates and the minor character of the associated complications, the RIRS procedure can sometimes be preferred to avoid complications related to PCNL in HSK anomaly with big sized kidney stones.

Prospective comparative study of ultramini percutaneous nephrolithotomy and retrograde intrarenal surgery in treatment of moderate-sized renal lower caliceal calculi

Objective To compare the effectiveness and safety of ultramini percutaneous nephrolithotomy (UMP) and retrograde intrarenal surgery (RIRS) in treatment of moderate-sized (about 1-2 cm) renal lower caliceal calculi. Methods From March 2015 to December 2016, patients in our hospital scheduled for surgery due to renal lower caliceal calculi with the greatest diameter of 10-22 mm were prospectively analyzed. Patients were randomized into two groups according to the random number table. Group UMP's operational channel was only F14 and the nephroscope's diameter was 1 mm. 200 μm holmium laser lithotripsy was used to break the stones which was rushed out by eddy cuurent. In Group RIRS, all patients needed placing a F6 double J stent preoperatively for two weeks.A flexible ureteroscope sheath required imbedding intraoperatively.The stones were smashed by 200 μm holmium laser lithotripsy through the WOLF flexible ureteroscope.The intraoperative and postoperative datas including stone-free status and the complications were compared. Results 100 patients were enrolled in the study 50 patients in Group UMP, 28 were male and 22 were female, mean age was 43.4±7.9 years old.Mean stone size was 14.5±3.0 mm(range 10-22 mm). Among them, 18 cases were complicated with mild and moderate hydronephrosis. The other 50 cases were allocated to Group RIRS, including 31 males and 19 females.Their mean age was 44.5±8.3 years old and mean stone size was 13.7±3.1mm (range 10-21 mm). Among them, 16 cases were complicated with mild and moderate hydronephrosis.No statistically significant difference were seen between the two groups(P>0.05). After three months’ follow-up, one-time stone free rate(SFR) of UMP group was 94.0%(47/50), which was significantly more superior than the 72.0%(36/50) of the RIRS group(P 0.05). Conclusions Both UMP and RIRS procedures are effective and safe in the treatment of moderate-sized renal lower caliceal calculi. Compared with RIRS, UMP may be more effective and has less operating time, however wtih more intraoperative blood loss. Key words: Renal lower caliceal calculi; Ultra-mini percutaneous nephrolithotomy; Flexible ureterorenoscope; Holmium laser; Prospective study

Ultralow Radiation Exposure During Flexible Ureteroscopy in Patients With Nephrolithiasis—How Far Can We Go?

To evaluate the feasibility and clinical performance of a novel surgeon technique and protocol targeting ultralow fluoroscopy usage in retrograde intrarenal surgery (RIRS). All RIRS procedures between 2009 and 2015 for 10- to 20-mm renal calculi performed by the same 2 experienced urologists were eligible. All procedures were performed using a highly standardized step-by-step RIRS technique. This technique was modified by the ultralow radiation exposure RIRS protocol; herein, as much as possible of the standardized steps were performed without radiation control targeting ultralow fluoroscopy usage. Primary end points were fluoroscopy time and dose area product. Secondary end points were stone-free rate (SFR) and intraoperative complications according to Satava classification. End points were evaluated using scatter plots and linear regression model. Overall, 174 procedures were assessed. Over the study period, fluoroscopy time and dose area product could be reduced from 167.7 s/318.4 cGy/cm2 in 2009 to 7.4 s/6.4 cGy/cm2 in 2015 (P <.001). SFR (66.7% in 2009; 100% in 2015) and complications (Satava 1 and 2: 28.5% and 4.8%, respectively) improved P <.1), and the surgical duration was reduced (91 minutes and 65 minutes, respectively, P <.001). Our findings revealed a continuous reduction of the amount of radiation used by the implementation of a novel ultralow X-ray usage protocol. SFR, complications, and surgical duration all improved, demonstrating that the novel protocol is as effective as current methods. Exposure to ionizing radiation can be significantly reduced if the presented protocol is followed strictly.

Flexible Ureterorenoscopy Versus Extracorporeal Shock Wave Lithotripsy for the Treatment of Renal Pelvis Stones of 10-20 mm in Obese Patients.

To compare outcomes of retrograde intrarenal surgery (RIRS) with extracorporeal shock wave lithotripsy (ESWL) as treatment of choice. A total number of 46 patients with renal pelvic stones 10-20 mm and body mass index (BMI) >30 randomized in two groups underwent RIRS and ESWL from 2011 to 2014 and followed for 3 months. The patients mean ± SD age was 36.1 ± 13.1 years in ESWL and 33.2 ± 11.4 years in RIRS groups (P = .1) with comparable BMI in both groups (36.2 vs 38.1). In ESWL and RIRS groups, the operation time was 72.2 ± 21 vs 66.5 ± 19 minutes (P = .061), respectively. Stone free rate (SFR) at 3 months was 68% in ESWL group vs 90.4% in RIRS group (P = .019). The complication rate was 20% in ESWL group vs 14.2% in RIRS group (P = .211) but all of them were minor and managed conservatively. According to our study, RIRS procedure in comparison with ESWL is a safe and successful option of treatment for renal pelvis stone of 10-20 mm in obese people.

66 Combined ultra-mini-percutaneous and retrograde intrarenal surgery procedure

66 Combined ultra-mini-percutaneous and retrograde intrarenal surgery procedure