Retrograde intrarenal surgery for renal stones - Part 1

Efficacy and safety of ureterorenoscopy in the elderly: A systematic review axnd meta-analysis

OBJECTIVE

Ureterorenoscopy (URS) is a common procedure performed for renal or upper ureteric stones. Nevertheless, the efficacy and safety of URS in the elderly is unclear. We conducted the first meta-analysis of literature comparing outcomes of URS between elderly and non-elderly patients.

METHODS

Embase, PubMed, Web of Science, and Scopus databases were searched for studies relevant to the review. The last date was 2nd September 2024. The elderly were defined as ≥ 65 or 60 years of age. Outcomes compared were stone-free rates (SFR), complications, and length of hospital stay (LOS).

RESULTS

Nine studies met the inclusion criteria. Pooled analysis showed that there was no difference in SFR between elderly and non-elderly groups after URS (OR: 0.96 95% CI: 0.81, 1.14 I2 = 3%). Meta-analysis failed to show any statistical significant in all complication rates (OR: 1.04 95% CI: 0.77, 1.40 I2 = 51%) as well as infectious (OR: 1.27 95% CI: 0.84, 1.92 I2 = 0%), medical (OR: 2.01 95% CI: 0.23, 17.57 I2 = 93%), surgical (OR: 1.18 95% CI: 0.68, 2.03 I2 = 0%) or Clavein Dindo grade ≥2 (OR: 1.02 95% CI: 0.60, 1.75 I2 = 0%) complications between elderly and non-elderly groups. Meta-analysis showed that the elderly had significantly longer LOS as compared to non-elderly patients (MD: 0.75 95% CI: 0.05, 1.45 I2 = 90%).

CONCLUSIONS

URS seems to efficacious and safe in the elderly. Patients ≥60 or 65 years of age have similar SFR and complication rates as younger patients. However, LOS may be increased in the elderly. More robust studies taking into account baseline characteristics and importantly presenting rates are needed to validate the current results.

Application of tip-flexible vacuum-assisted ureteral access sheath in flexible ureteroscopic laser lithotripsy for renal stones in a child after pyeloplasty: a case report

Objectives

To explore the application of tip-flexible vacuum-assisted ureteral access sheath-assisted retrograde intrarenal stone surgery/flexible ureteroscopic lithotripsy in children.

Patients and methods

A retrospective analysis was conducted on the clinical data of a pediatric patient who developed kidney stones following pyeloplasty for congenital ureteropelvic junction obstruction. The child underwent tip-flexible vacuum-assisted ureteral access sheath-assisted retrograde intrarenal stone surgery under general anesthesia. Inpatient records and postoperative follow-up results were collected.

Results

The kidney stones were utterly removed, and there were no complications like infection, bleeding, or secondary obstruction. Moreover, there was no significant damage to the anastomotic site after pyeloplasty.

Conclusion

The use of tip-flexible vacuum-assisted ureteral access sheath-assisted flexible ureteroscopic lithotripsy is safe and effective for pediatric lithotripsy.

Effect of preoperative Silodosin on facilitating access sheath placement in retrograde intrarenal surgery. A randomized controlled studys

Introduction

to evaluate the effect of preoperative Silodosin on ureteric dilatation to facilitate ureteral access sheath (UAS) placement and reduction of ureteral wall injury in retrograde intrarenal surgery (RIRS).

Methods

one hundred and twenty patients with renal or ureteric stones were randomly allocated into 2 equal groups. Group A represents patients who received a 7-day preoperative single dose Silodosin before RIRS while Group B represents patients who received a placebo for the same regimen. Our primary outcome was to assess the success rate of (UAS) placement. Our secondary outcomes were to evaluate the perioperative complication rate, stone-free rate, hospital stay, and cost analysis.

Results

In our study, Silodosin showed a higher success rate for (UAS) insertion compared to placebo with a statistically significant difference (p-value = 0.04). Spontaneous UAS insertion in the Silodosin group was 58.3%, which was increased with active ureteric dilatation to 98.3%. Preoperative Silodosin led to less postoperative pain and analgesics requirements without impacting postoperative hospital stay or stone-free rate. There was less ureteric injury incidence in the Silodosin group compared to placebo with a statistically significant difference (p-value = 0.002).

Conclusion

Preoperative Silodosin facilitates UAS insertion with a protective role against ureteric injury compared to placebo.

Upper urinary tract stone characteristics and outcome of retrograde intra renal surgery with laser lithotripsy in a Nigerian tertiary hospital: a retrospective study

Background

This study is therefore aimed at assessing upper urinary tract stone characteristics, the outcome of retrograde intrarenal surgery with laser lithotripsy, and factors predicting stone-free status.

Methodology

This was a retrospective cross-sectional study carried out on all patients who had retrograde intra-renal surgery with laser lithotripsy for upper urinary tract stones from 2021-2023 at the Urology unit, department of Surgery, University of Benin Teaching Hospital. Electronic medical records were retrieved with data on demographics, serum calcium level, and non-contrast computed tomography scans assessing stone size, location, laterality, multiplicity, density, and renal anatomy.

Results

The data Thirty- three patients were extracted and analysed with a mean age of 43,70+/- 11.44 years, 54.5% of patients were male. The mean duration of admission was 2.4+/-1.5 days. The mean body mass Index was 26.84+/- 4.37 kg/m2. All patients had flank pains; 7(41.2%) patients had bilateral renal stones. The majority of renal stones 8(47.1%) were located in the lower pole of the kidney. A greater proportion of calculus was ureteric 23(69.7%), mean stone size was 13.2+/- 15.2mm, while mean stone density was 817+/- 285.5 HU. Fifteen participants (45.5%) had multiple stones. Stone clearance assessed on imaging was 75.8%. Age, sex, stone size, density and location, and multiplicity of stones were statistically significant determinants of stone clearance (p= 0210, 1.000, 0.220, 0.380. 0.366 and 1.000) respectively, similarly, no statistically significant predictors of stone clearance were found in this study.

Conclusion

The study revealed a predominance of upper urinary tract stones in males, with most patients being overweight. There was a weak correlation between stone density and serum calcium level in this study. Findings in this study revealed no statistically significant determinant or predictors of stone clearance.

Prediction of percutaneous nephrolithotomy outcomes and flexible ureteroscopy outcomes using nephrolithometry scoring systems

BACKGROUND

Kidney stones account for a high proportion of urological emergencies. The main objective of this paper is to evaluate the predictive ability of five scoring systems for overall stone-free status and postoperative complications after percutaneous nephrolithotomy and retrograde ureteroscopy.

MATERIALS AND METHODS

This study retrospectively analysed 312 cases of kidney stone patients between January 2021 and May 2022 at our centre. Multivariate logistic regression as well as ROC curves were applied to determine the ability to evaluate each scale to predict stone-free rates and postoperative complications.

RESULTS

179 patients have undergone PCNL. After multivariate logistic regression, the S.T.O.N.E score and history of ipsilateral renal surgery were predictive of stone-free status, and the predictive power of the S.T.O.N.E score was higher than that of history of ipsilateral renal surgery. Grade 1 complications were considered to be related to Guy's score and grade 2 complications were considered to be related to history of diabetes mellitus. 133 patients have undergone f-URS. After multivariate logistic regression analysis, the modified S-ReSC score, RUSS score, and R.I.R.S score were predictive of stone-free status, with the R.I.R.S score being the strongest predictor. Evidence of grade 2 complications was considered to be related to abnormal renal function.

CONCLUSION

For PCNL, the S.T.O.N.E score had the best efficacy in predicting stone-free status, and the Guy's score had the best efficacy in predicting postoperative complications; for f-URS, the R.I.R.S score had the best efficacy in predicting stone-free status, and no scoring system predicted postoperative complications.

Percutaneous nephrolithotomy versus retrograde intrarenal surgery for treatment of renal stones in adults

BACKGROUND

Kidney stones (also called renal stones) can be a source of pain, obstruction, and infection. Depending on size, location, composition, and other patient factors, the treatment of kidney stones can involve observation, shock wave lithotripsy, retrograde intrarenal surgery (RIRS; i.e. ureteroscopic approaches), percutaneous nephrolithotomy (PCNL), or a combination of these approaches.

OBJECTIVES

To assess the effects of percutaneous nephrolithotomy (PCNL) versus retrograde intrarenal surgery (RIRS) for the treatment of renal stones in adults.

SEARCH METHODS

We performed a comprehensive search of the Cochrane Library, MEDLINE, Embase, Scopus, and two trials registries up to 23 March 2023. We applied no restrictions on publication language or status.

SELECTION CRITERIA

We included randomized controlled trials that evaluated PCNL (grouped by access size in French gauge [Fr] into three groups: ≥ 24 Fr [standard PCNL], 15-23 Fr [mini-PCNL and minimally invasive PCNL], and < 15 Fr [ultra-mini-, mini-micro-, super-mini-, and micro-PCNL]) versus RIRS.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies and extracted data from the included studies. Our primary outcomes were stone-free rate, major complications, and need for secondary interventions. Our main secondary outcomes were unplanned medical visits to emergency/urgent care or outpatient clinic, length of hospital stay, ureteral stricture or injury, and quality of life. We performed statistical analyses using a random-effects model. We rated the certainty of evidence using GRADE criteria. We adopted a minimally contextualized approach with predefined thresholds for minimal clinically important differences (MCIDs).

MAIN RESULTS

We included 42 trials assessing the effects of PCNL versus RIRS in 4571 randomized participants. Twenty-two studies were published as full-text articles, and 20 were published as abstract proceedings. The average size of stones ranged from 10.1 mm to 39.1 mm. Most studies did not report sources of funding or conflicts of interest. The main results for the most important outcomes are summarized below. Stone-free rate PCNL compared with RIRS may improve stone-free rates (risk ratio [RR] 1.13, 95% confidence interval [CI] 1.08 to 1.18; I2 = 71%; 39 studies, 4088 participants; low-certainty evidence). Based on 770 participants per 1000 being stone-free with RIRS, this corresponds to 100 more (62 more to 139 more) stone-free participants per 1000 with PCNL (an absolute difference of 10%, where the predefined MCID was 5%). Major complications PCNL compared with RIRS probably has little or no effect on major complications (RR 0.86, 95% CI 0.59 to 1.25; I2 = 15%; 34 studies, 3649 participants; moderate-certainty evidence). Based on 31 complications in the RIRS group, this corresponds to six fewer (13 fewer to six more) major complications per 1000 with PCNL (an absolute difference of 0.6%, where the predefined MCID was 2%). Need for secondary interventions PCNL compared with RIRS may reduce the need for secondary interventions (RR 0.31, 95% CI 0.17 to 0.55; I2 = 61%; 21 studies, 2005 participants; low-certainty evidence). Based on 222 secondary interventions in the RIRS group, this corresponds to 153 fewer (185 fewer to 100 fewer) secondary interventions per 1000 with PCNL (an absolute difference of 15.3%, where the predefined MCID was 5%). Unplanned medical visits No studies reported unplanned medical visits. Length of hospital stay PCNL compared with RIRS may extend length of hospital stay (mean difference 1.04 days more, 95% CI 0.27 more to 1.81 more; I2 = 100%; 26 studies, 2804 participants; low-certainty evidence). This effect size is greater than the predefined MCID of one day. Ureteral stricture or injury PCNL compared with RIRS may have little or no effect on the occurrence of ureteral strictures (RR 0.93, 95% CI 0.39 to 2.21; I2 = 0%; 13 studies, 1574 participants; low-certainty evidence). Based on 14 ureteral strictures in the RIRS group, this corresponds to one fewer (nine fewer to 17 more) ureteral strictures per 1000 with PCNL (an absolute difference of 0.1%, where the predefined MCID was 2%). Quality of life No studies reported quality of life.

AUTHORS' CONCLUSIONS

Based on a large body of evidence from 42 trials, we found that PCNL compared with RIRS may improve stone-free rates and may reduce the need for secondary interventions, but probably has little or no effect on major complications. PCNL compared with RIRS may have little or no effect on ureteral stricture rates and may increase length of hospital stay. We found no evidence on unplanned medical visits or participant quality of life. Because of the considerable shortcomings of the included trials, the evidence for most outcomes was of low certainty. Access size for PCNL was less than 24 Fr in most studies that provided this information. We expect the findings of this review to be helpful for shared decision-making about management choices for individuals with renal stones.

Effective and Economical Option of Anesthesia in Retrograde Intrarenal Surgery

Background

There is only limited data in the literature showing the effect of anesthesia methods on the success of retrograd intrarenal surgery. The aim of this study was to compare and evaluate retrograd intrarenal surgery cases performed under spinal and general anesthesia in terms of effectiveness, cost, hospitalization time and complications.

Methods

A total of 337 patients who underwent retrograd intrarenal surgery due to kidney stones between 2014 and 2019 were retrospectively evaluated. In our study, the patients were divided into two groups according to the anesthesia method administered: Group 1 consisted of 172 patients who received spinal anesthesia and Group 2 comprised 165 patients administered general anesthesia. Both groups were compared in terms of demographic data, localization and size of stone, radiographic stone density, operation time, complications, need for postoperative analgesia, length of hospitalization, and stone free rate.

Results

The cost of general anesthesia was significantly higher compared to that of spinal anesthesia (p < 0.001). The analgesia application administered within the first six postoperative hours was significantly higher in the general anesthesia group (p < 0.001). In other findings, there was no statistically significant difference between the two groups.

Conclusion

Retrograd intrarenal surgery can be performed with similar safety and effectiveness under both general and spinal anesthesia. However, spinal anesthesia seems to be more advantageous due to the patients' lower need for analgesics in the early postoperative period and the lower cost of the anesthetics used.

Identification of Protein-Coding Gene Structure and Protein-Related Genes and Their Splicing Sites in Kidney Stone Disease: A Protein Big Data Analysis

The study of protein-coding gene structure and protein-related genes in kidney stone disease is used for accurate identification of splicing sites and accurate location of gene exon boundaries, which is one of the difficulties and key problems in understanding the genome and discovering new genes. Prediction techniques based on signal characteristics of conserved sequences around splicing sites, such as the weighted array model (WAM), are widely used. On this basis, several other features that can be used for splicing site recognition (such as the base composition of splicing site upstream and downstream sequences, the change of signal and base composition of upstream and downstream sequences with the C + G content of adjacent sequences) were mined further, and a model was developed to describe these features. In this study, a log-linear model that can effectively integrate these features for splicing site recognition was designed, and a SpliceKey programme was developed. The findings reveal that SpliceKey's splicing site identification accuracy is not only much better than the WAM approach, but also better than DGSplice.

Safety and Efficacy of Flexible Ureterorenoscopy Surgery: Results of Our Large Patient Series

Introduction: The aim of our study is to evaluate the success rates of our retrograde intrarenal surgery operations and the complications we encountered and to determine in which kidney segment the operations were more successful with flexible ureterorenoscopy.

Methods: The records of retrograde intrarenal surgery operations performed between March 2013 and January 2021 in Health Sciences University, Adana City Training and Research Hospital, urology clinic were analyzed retrospectively. Patients’ age, body mass index, operation side, stone size, stone density, duration of operation, first-day and first-month operation success status, presence of preoperative and postoperative ureteral stent, preoperative and postoperative first-day and first-month creatinine levels, and preoperative and postoperative first-day and first-month hematocrit levels were recorded.

Results: Our study consisted of a total of 1128 patients, 618 males (54.7%) and 510 (45.2%) females, with an average age of 42.3±14.4. Kidney stones were most commonly found in the renal pelvis (54.2%). The postoperative first-day success rate was highest in the pelvis stone group (P=0.009). The first month’s success rates were highest in those with pelvic stones (93.1%), and the lowest in patients with multiple stones (85.7%). Patients’ operation time, postoperative hematocrit and creatinine levels, and complications did not differ statistically between the groups (P>0.05).

Conclusion: Retrograde intrarenal surgery is an acceptable minimally invasive and effective surgery with low complication rates. There is a high success rate, especially in pelvis stones.

Perirenal Extravasation After Retrograde Intrarenal Surgery for Renal Stones: A Prospective Study

Background

The incidence and consequences of the perirenal extravasation of the irrigation fluid during retrograde intrarenal surgery (RIRS) are not fully elucidated. The objective of this study was to assess the incidence, risk factors, and complications of perirenal extravasation of irrigation fluid during RIRS.

Methods

This prospective observational study was conducted in the Department of Urology, Bir Hospital, Kathmandu, Nepal, from January 2020 to March 2021. Patients undergoing RIRS for renal stones less than 2 cm in diameter were included in the study. Irrigation during the procedure was performed using isotonic normal saline under gravity at 50 cm from the symphysis pubis of patients with intermittent manual compression if required. Lithotripsy was performed with 120-Watt Ho:YAG laser using 200-micron laser fiber. Retrograde pyelogram was performed after the completion of lithotripsy to document the presence or absence of extravasation on fluoroscopic images. A double-J stent was placed at the end in all patients. Patients were observed for systemic inflammatory response syndrome (SIRS) features. Postoperative abdominal ultrasonography was performed on the first postoperative day to assess the perirenal collection together with complete blood count. The visual analogue scale (VAS) was used to assess pain in postoperative period. The preoperative patient’s and stone characteristics, hydronephrosis, intraoperative characteristics, and postoperative findings were analyzed.

Results

A total of 71 patients who underwent RIRS during the study period were analyzed. The mean (SD) stone size was 13.19 (3.12) mm. Intraoperative perirenal extravasation of contrast was noted in eight (11.26%) patients; however, no patient had ipsilateral perirenal collection on ultrasonography obtained on the first postoperative day. No significant differences were observed among patients with or without perirenal extravasation in terms of mean stone size, laser settings, operative duration, and lasing duration. Use of ureteral access sheath (UAS) was associated with lower incidence of extravasation; however, it was not significant. SIRS was documented in eight patients overall, with none of the patients with extravasation having features of SIRS. Patients with extravasation experienced more postoperative flank pain (p<0.05).

Conclusion

Perirenal extravasation was common during RIRS and was associated with higher postoperative pain scores. Stone size, use of UAS, laser settings, operative duration, and lasing duration were not associated with an increased risk of extravasation. Extravasation was not associated with increased postoperative complications.

A comparative study of minimally invasive percutaneous nephrolithotomy and retrograde intrarenal surgery for solitary renal stone of 1-2 cm

Background:

PCNL is the treatment of choice for renal stones. But wide array of complications due to larger tract size(>20 Fr) has lead to development of improved techniques like miniPCNL(<20 Fr) and RIRS(Retrograde intrarenal surgery).

Aim and Objective:

To perform a study comparing miniPCNL with RIRS for renal stones 1-2 cm with respect to stone free rate , complications and quality of life.

Materials and Methods:

A prospective, randomised study was carried out our tertiary care centre, recruiting 40 patients in each group from Dec 2016 to Oct 2018. Patients demographic characteristics, operative findings, surgical outcomes and quality of life( SF-36 questionnaire) were recorded with 3 months of follow-up.

Results:

RIRS has longer operative time (69.75 min > 51.58 min; p=0.003), lesser radiation exposure (p=0.012), shorter hospital stay (p =0.15), lesser blood loss and lesser post operative pain on POD1 and POD2 (p =0.005, p=0.001 respectively). RIRS group patients sufferred more post op complications (p=0.03 )of which urosepsis was most common. Stone free rate is significantly better(p =0.003) in miniPCNL group on POD1 , while SFR's at 1 month (miniPCNL-90% and RIRS -85%) and 3 month (miniPCNL- 92.5% and RIRS -87.5%) was better in miniPCNL group, but statistically insignificant.On subgroup analysis SFR in lower pole calculus was better in miniPCNL group at 1month and 3 month (p=0.008). Second intervention for stone clearance was required in 3 patients of miniPCNL and 5 patients of RIRS, out of which 4 had lower pole stone.No significant differnce was found in quality of life in both groups at 1 month.

Conclusion:

MiniPCNL is a better treatment modality for higher single step stone free rate, shorter operative time and fewer postop complication. RIRS has SFR slightly less than miniPCNL but has less radiation exposure and much less post operative pain. There is no significant difference in quality of life in both groups.

Visual-electromagnetic system: A novel fusion-based monocular localization, reconstruction, and measurement for flexible ureteroscopy

BACKGROUND

During flexible ureteroscopy (FURS), surgeons may lose orientation due to intrarenal structural similarities and complex shape of the pyelocaliceal cavity. Decision-making required after initially misjudging stone size will also increase the operative time and risk of severe complications.

METHODS

A intraoperative navigation system based on electromagnetic tracking (EMT) and simultaneous localization and mapping (SLAM) was proposed to track the tip of the ureteroscope and reconstruct a dense intrarenal three-dimensional (3D) map. Furthermore, the contour lines of stones were segmented to measure the size.

RESULTS

Our system was evaluated on a kidney phantom, achieving an absolute trajectory accuracy root mean square error (RMSE) of 0.6 mm. The median error of the longitudinal and transversal measurements was 0.061 and 0.074 mm, respectively. The in vivo experiment also demonstrated the effectiveness.

CONCLUSION

The proposed system worked effectively in tracking and measurement. Further, this system can be extended to other surgical applications involving cavities, branches and intelligent robotic surgery.

A cut-off value for the operation time and other risk factors in terms of the infection risk for flexible ureterorenoscopy

OBJECTIVES

To investigate the operation time (OT) and ureteral access sheath (UAS) usage with the infection rates and to determine a cut-off value for OT.

METHODS

We retrospectively analysed the data of the patients who underwent flexible ureterorenoscopy (FURS) for renal stones larger than 20 mm between 2010 and 2019. The investigated parameters were OT, UAS using, and infection status. The data were analysed by forming two groups according to whether the OT was less than 60 minutes and more, whether the UAS was used and whether an infection occurred. In addition, independent risk factors that may affect postoperative urinary infection development were also investigated by logistic regression analysis. And, a Receiver Operating Characteristic (ROC) curve analysis was applied to determine a cut-off value in OT terms, where infection rates increase more.

RESULTS

A total of 575 patients were enrolled in the study. The rates of the usage of UAS and infection were greater statistically in the group for longer than 60 minutes. OT was longer statistically in the infection group than in the group without infection (94.1 ± 14.2 and 68.01 ± 23.1, for groups 1 and 2, respectively, P < .05, Table 2). OT was statistically longer in the UAS group than the unused one (79.3 ± 24.4 and 66.7 ± 22.4, for groups 1 and 2, respectively, P < .05, Table 3). ROC analyses revealed a cut-off point of 87.5 min for OT in terms of infection rate.

CONCLUSION

While the infection risk increases when OT exceeds 60 minutes, FURS can be safely performed up to 87.5 minutes with 89% sensitivity and 69% specificity infection risk.

External validation of the R.I.R.S. scoring system to predict stone-free rate after retrograde intrarenal surgery

Background

The R.I.R.S. scoring system is defined as a novel and straightforward scoring system that uses the main parameters (kidney stone density, inferior pole stones, stone burden, and renal infundibular length) to identify most appropriate patients for retrograde intrarenal surgery (RIRS). We strived to evaluate the accuracy of the R.I.R.S. scoring system in predicting the stone-free rate (SFR) after RIRS.

Methods

In our medical center, we retrospectively analyzed charts of patients who had, between September 2018 and December 2019, been treated by RIRS for kidney stones. A total of 147 patients were enrolled in the study. Parameters were measured for each of the four specified variables.

Results

Stone-free status was achieved in 105 patients (71.43%), and 42 patients had one or more residual fragments (28.57%). Differences in stone characteristics, including renal infundibulopelvic angle, renal infundibular length, lower pole stone, kidney stone density, and stone burden were statistically significant in patients whether RIRS achieved stone-free status or not (P < 0.001, P: 0.005, P < 0.001, P < 0.001, P: 0.003, respectively). R.I.R.S. scores were significantly lower in patients treated successfully with RIRS than patients in which RIRS failed (P < 0.001). Binary logistic regression analyses revealed that R.I.R.S. scores were independent factors affecting RIRS success (P = 0.033). The area under the curve of the R.I.R.S. scoring system was 0.737.

Conclusions

Our study retrospectively validates that the R.I.R.S. scoring system is associated with SFR after RIRS in the treatment of renal stones, and can predict accurately.

Retrograde intrarenal surgery: Past, present, and future

With the recent technological advancements in endourology, retrograde intrarenal surgery has become a more popular procedure for treatment of urolithiasis. Furthermore, since the introduction of new laser systems and advanced flexible ureteroscopy with miniaturized ureteroscopes, the treatment indications for retrograde intrarenal surgery have expanded to include not only larger renal stones of >2 cm but also upper urinary tract urothelial carcinoma, ureteral stricture, and idiopathic renal hematuria. Clinicians must keep up with these trends and make good use of these technologies in the rapidly changing field of endourology. Simultaneously, we must consider the risk of various complications including thermal injury due to laser use, ureteral injury caused by the ureteral access sheath, and radiation exposure during retrograde intrarenal surgery with fluoroscopic guidance. This review focuses on the past, present, and future of retrograde intrarenal surgery and provides many topics and clinical options for urologists to consider.

Case Report: An occurrence of steinstrasse in retrograde intra renal surgery (RIRS) for large staghorn kidney stone: a difficult experience in managing surgical outcomes

Immediate removal of staghorn kidney stones is important to prevent life-threatening complications. With the advancement of endoscopic technology, retrograde intrarenal surgery (RIRS) is now an alternate treatment to the standard percutaneous nephrolithotomy (PCNL) for stones removal. However, when used to treat large stones (>3cm), RIRS can cause the formation steinstrasse (SS). Here, we present the case of a 68-year-old man with multiple stones in the collecting system of the right kidney after initial treatment with RIRS. After two years of multiple interventions, the SS was completely removed. To prevent this complication in patients, a detailed assessment of the stone (size, location) and renal anatomy should be completed before RIRS is performed.

Effects of flexible ureteroscopy on kidney: A prospective clinical trial

OBJECTIVE

To investigate the effects of flexible ureteroscopy (F-URS) on the operated side of a kidney by assessing the renal damage markers, urine neutrophil gelatinase-related lipocalin (NGAL) and serum cystatin-C (Cys-C), and overall kidney function with the measurements of standard serum creatinine and urine albumin and protein levels.

MATERIAL AND METHODS

A total of 30 patients who underwent F-URS for treatment of upper urinary stone disease were prospectively evaluated. Preoperative serum urea, creatinine, and Cys-C levels were noted. Levels of urine albumin, protein, creatinine, and NGAL in spot urine samples from the operated side of a kidney obtained through the access sheath preoperatively and through the ureteral catheter 1 and 24 hours postoperatively were also measured. Preoperative and postoperative parameter levels were statistically compared.

RESULTS

The patients' mean age was 46.6±15.9 years. The mean operative and fluoroscopy times were 90.67±32.5 and 3.15±1.43 minutes, respectively. The urine creatinine, albumin, protein, albumin/creatinine, and protein/creatinine levels were similar in preoperative and postoperative periods. Postoperative serum urea, creatinine, and Cys-C levels and urine NGAL and NGAL/creatinine levels were not also found with remarkable changes from the baseline levels.

CONCLUSION

F-URS is a safe therapeutic intervention in the treatment of urolithiasis, especially regarding renal damage, and functional outcomes.

Effect of JJ stent on outcomes of extracorporeal shock wave lithotripsy treatment of moderate sized renal pelvic stones: A randomized prospective study

PURPOSE

To evaluate the effect of JJ stents on SWL treatment of moderate (15-25mm) renal pelvic stones.

MATERIALS AND METHODS

Between January 2016 and December 2017, a total of 152 adult patients who were planned to undergo SWL for a single radiopaque renal pelvic stone were included in the study. Patients with solitary kidney, congenital abnormality, skeletal tract abnormalities, previous urinary system surgery, hydronephrosis (grade 2 or more), untreated urinary tract infection, bleeding disorder, and suspected pregnancy were excluded. The remaining 114 patients were randomly divided into two groups; non-stented and stented. Twenty-two patients whose stone could not be fragmented despite 3 consecutive sessions were also excluded from the study. A total of 92 patients (54 non-stented and 38 stented) were included in the final analysis.

RESULTS

There was no significant difference in terms of age, sex, body mass index, renal parancyhimal thickness, hydronephrosis, skin-to-stone distance, Hounsfield units, and stone size between the groups. Success was significantly higher in the stented group than in the non-stented group (71% vs. 39%, P=.002). In stone-free patients, the number of emergency department visits and analgesic tablet consumption was significantly lower in the stented group than in the non-stented group (P<.001 and P<.001, respectively). In non- stone-free patients, analgesic tablet consumption was significantly lower in the stented group than in the non-stented group (P=.004).

CONCLUSIONS

Pre-stenting before SWL treatment of moderate sized renal pelvic stones has some advantages in terms of success, emergency service visits, and analgesic tablet consumption.

Could surgical experience of adult endourologist overcome the learning curve of retrograde intrarenal surgery in children?

With the increasing of the prevalence of pediatric urolithiasis (1-5%), retrograde intrarenal surgery (RIRS) is emerging as preferred option for the management of stones in pediatric patients. Although the principles of RIRS developed in adults can be applied in children, also expert adult endourologists feel uncomfortable to approach young patients due to long learning curve that usually is expected to be required in this particular setting. The aim of the study was to compare peri- and postoperative outcomes of RIRS in pediatric and adult patients performed by a single surgeon expert in adult endourology (> 500 RIRS) with no experience in pediatric urology. Data on patient characteristics of 30 consecutive patients (15 adults and 15 children) undergoing RIRS at our institution were collected retrospectively from January 2016 to October 2018. Mean age for the pediatric group was 11.8 years (IQR 8-16) and for the adult group was 56 years (IQR 49-58). No significative differences between the two groups in terms of peri- and postoperative outcomes were found. The most common complication was hematuria in 2/30 patients (1 children vs 1 adults) and fever 2/30 (1 pediatric patient vs 1 adult) (p = 1.00) that required antibiotic treatment (Clavien Dindo 2). Median length of stay was 1 day (IQR 1-1 days) in both groups (p = 1.00). Stone-free rate was 86.7% in children and 80% in adults (p = 0.624). Our preliminary experience suggests that expert adult endourologist can manage successfully also pediatric cases with results comparable to adults and low complication rate.

Updates in endourological management of urolithiasis

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

Retrograde intrarenal surgery vs miniaturized percutaneous nephrolithotomy to treat lower pole renal stones 1.5-2.5 cm in diameter

AIM

To compare the outcomes of retrograde intrarenal surgery (RIRS) and miniaturized percutaneous nephrolithotomy (mini-PCNL) in treating lower pole (LP) renal stones with a diameter of 1.5-2.5 cm.

METHODS

A total of 216 patients who underwent mini-PCNL (n = 103) or RIRS n = 113) for LP stones with a diameter of 1.5-2.5 cm were enrolled between December 2015 and April 2017 at the Urology Department of Ningbo Urology and Nephrology Hospital.

RESULTS

Significant differences were found in the hospital stay (9.39 ± 4.01 vs 14.08 ± 5.26, P < 0.0001) and hospitalization costs (2624.5 ± 513.36 vs 3255.2 ± 976.5, P < 0.0001) between the RIRS and mini-PCNL groups. The mean operation time was not significantly different between the RIRS group (56.48 ± 24.77) and the mini-PCNL group (60.04 ± 30.38, P = 0.345). The stone-free rates at the first postoperative day (RIRS vs mini-PCNL: 90.2% vs 93.2%, P = 0.822) and the second month postoperatively (RIRS vs mini-PCNL: 93.8% vs 95.1%, P = 0.986) were not significantly different.

CONCLUSION

RIRS and mini-PCNL are both safe and effective methods for treating LP stones with a diameter of 1.5-2.5 cm. RIRS can be considered as an alternative to PCNL for the treatment for LP stones of 1.5-2.5 cm.

Prediction of stone-free status after single-session retrograde intrarenal surgery for renal stones

OBJECTIVE

To determine the possible factors effecting stone-free status (SFS) after single-session retrograde intrarenal surgery (RIRS) for renal stones.

MATERIAL AND METHODS

We retrospectively analyzed the charts of 100 consecutive patients who underwent RIRS. Unilateral procedures performed for single renal stones were included in the study. The studied parameters included patient demographics, stone characteristics (size, volume, location and attenuation according to Hounsfield unit [HU]), operation time, presence of preoperative double-J stent (DJS), use of ureteral access sheath (UAS) and SFS.

RESULTS

The study population consisted of 100 patients where 43 of them were stone free and remaining 57 had residual stones. The mean age of the patients was 47.2±13.4 years. The mean stone size (largest dimension), stone attenuation and stone volume were 14.8±5.8 mm, 1010±416 HU and 937±929 mm³, respectively. The mean operative time was 60.8±24.2 minutes. Mean stone size, volume and HU were higher in the RS group compared to SF group but without any statistically significant difference, 15.2±6.1 vs. 14.2±5.3 mm, 1056±1037 mm³ vs. 780±745 mm³ and 1061±374 HU vs. 942±462 HU, respectively (p=0.490, p=0.135 and p=0.226). In multivariate regression analysis stone location and UAS use were found to be the significant predictors of SFS. Patients with lower pole stones are 2.25 times likely to have residual stones after RIRS compared to patient's having stones at other localizations (p<0.001).

CONCLUSION

Stone volume could be a more reliable parameter than stone size in predicting RIRS success. Lower pole stone location and UAS use could be considered the most significant predictors of SFS after single session RIRS for single renal stones.

Flexible ureterorenoscopy is associated with less stone recurrence rates over Shockwave lithotripsy in the management of 10-20 millimeter lower pole renal stone: medium follow-up results

Purpose

To identify the role of shock wave lithotripsy (SWL) and flexible ureterorenoscopy (f-URS) on the stone recurrence, in the management of 10-20 millimeter lower pole stone (LPS) with medium follow-up outcomes.

Materials and Methods

The patients’ charts which were treated with SWL or f-URS for LPS between January 2011 and September 2013 were analyzed, retrospectively. Patients who had a solitary 10-20mm LPS were enrolled into the study. In both procedures, patient was accepted as stone free, if complete stone clearance was achieved in the 3rd month abdominal computed tomography. Only patients with a stone free status were evaluated in follow ups.

Results

The stone-free rate was 77.9% (88/113 patients) for the SWL group and 89% (114/128 patients) for the f-URS group (p=0.029). Stone recurrence was detected in 28 (35.4%) patients in SWL group and in 17 (17.2%) patients in f-URS group (p=0.009). Stone types and 24 hour urine sample results were similar between groups (p=0.123 vs p=0.197, respectively). Multivariate regression analysis revealed that f-URS procedure and absence of abnormality in 24 hour urine analysis significantly decreased stone recurrence in medium term follow-up (p=0.001 and p<0.001, respectively).

Conclusions

Our study showed for the first time, that patients which underwent f-URS for LPS, faced less stone recurrence, independent from diet regimen and metabolic evaluation in medium term follow-up. Additionally, presence of abnormality in 24 hour urine analysis increase the stone recurrence risk in follow-ups.