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

Status study of clinical application of ureteral access sheath in urology: a narrative review

Background and Objective

As one of the effective minimally invasive methods for upper urinary tract stone treatment, ureteroscopic lithotripsy has gradually become the mainstream surgical approach. The routine use of ureteral access sheaths (UAS) during ureteroscopic lithotripsy has plenty of advantages. Although many concerns have emerged in the clinical practice of the UAS, the clinically improved devices have addressed these issues. This article reviews the advantages, existing issues, and current improvements of UAS in clinical practice, aiming to provide references for better clinical application and further improvements of UAS.

Methods

We searched in PubMed database using the terms: "ureteral access sheath", "ureteroscopic lithotripsy" or "flexible ureteroscope". Articles were independently evaluated for inclusion based on predetermined criteria.

Key Content and Findings

The routine use of UAS during ureteroscopic lithotripsy facilitates the entry and exit of the ureteroscope, improves intraoperative visibility, and reduces postoperative complications. However, concerns over ureteral wall injury, difficulty in controlling renal pelvic pressure, lack of reduction in operation time, failure to increase stone free rates, and controversies regarding the ratios of endoscope-sheath diameter have limited the clinical application of UAS. The emergence of clinically improved devices such as intelligent pressure controlled, tip bendable, and rigid ureteroscope aided UAS has addressed these issues, laying a foundation for their further clinical application.

Conclusions

The clinical improvement of the UAS can serve as a bridge for the widespread usage of the ureteroscopic lithotripsy. In the future, we anticipate more innovative advancements in UAS, making their clinical use even more practical and convenient.

Comparison of Renal Tubular Damage with Kidney Injury Molecule-1 in Open and Laparoscopic Colorectal Cancer Surgery

Background and Objectives: Colorectal cancer is the third most common type of cancer in men and women. With advancements in technology, minimally invasive treatment options have become increasingly prominent in colorectal cancer surgery. This study aimed to compare the increased intra-abdominal pressure in laparoscopic colon and rectal surgery with open procedures using kidney injury molecule-1 (KIM-1) secreted from renal tubules. Materials and Methods: We enrolled 46 patients diagnosed with colon cancer who underwent laparoscopic and open surgical procedures at our clinic. The patients were prospectively randomized into five groups: 10 laparoscopic right hemicolectomies (Group 1), 8 open right hemicolectomies (Group 2), 8 laparoscopic anterior resections (LARs) (Group 3), 11 open anterior resections (Group 4), and 9 laparoscopic low anterior resections (Group 5). Urine samples were collected from the patients preoperatively, postoperatively at the 4th hour, and postoperatively on the 14th day, and the urine KIM-1 levels and urine creatinine (Cr) values were measured. The urine KIM-1/Cr ratios were subsequently calculated. Results: The urinary KIM-1/Cr levels increased at the 4th postoperative hour after the open and laparoscopic procedures. On postoperative day 14, the urinary KIM-1/Cr levels were lower than those in the preoperative period in all groups, except the LAR group. Conclusions: Our study shown that the average pressure in laparoscopic colon and rectal surgery did not have a long-term impact on kidney injury in comparison to open colon and rectal surgery.

Retrograde intrarenal surgery with or without ureteral access sheath: a systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

The ureteral access sheath (UAS) is a medical device that enables repeated entrance into the ureter and collecting system during retrograde intrarenal surgery (RIRS). Its impact on stone-free rates, ureteral injuries, operative time, and postoperative complications remains controversial. Therefore, we performed a systematic review and meta-analysis comparing RIRS with versus without UAS for urolithiasis management.

PURPOSE

To compare outcomes from retrograde intrarenal surgery (RIRS) for stone extraction with or without ureteral access sheath (UAS); evaluating stone-free rate (SFR), ureteral injuries, operative time, and postoperative complications.

MATERIALS AND METHODS

We systematically searched PubMed, Embase, and Cochrane Library in June 2024 for randomized controlled trials (RCTs) evaluating the efficacy and safety outcomes of UAS use in RIRS for urolithiasis treatment. Articles published between 2014 and 2024 were included. Pooled risk ratios (RRs) and mean differences (MDs) were calculated for binary and continuous outcomes, respectively.

RESULTS

Five RCTs comprising 466 procedures were included. Of these, 246 (52.7%) utilized UAS. The follow-up ranged from 1 week to 1 month. UAS reduced the incidence of postoperative fever (RR 0.49; 95% confidence interval [CI] 0.29-0.84; p=0.009), and postoperative infection (RR 0.50; 95% CI 0.30-0.83; p=0.008). There were no significant differences between groups in terms of SFR (RR 1.05; 95% CI 0.99-1.11; p=0.10), ureteral injuries (RR 1.29; 95% CI 0.95-1.75; p=0.11), operative time (MD 3.56 minutes; 95% CI -4.15 to 11.27 minutes; p=0.36), or length of stay (MD 0.32 days; 95% CI -0.42 to 1.07 days; p=0.40).

CONCLUSION

UAS leads to a lower rate of post-operative fever and infection. However, UAS did not significantly reduce or increase the SFR or the rate of ureteral injuries during RIRS for patients with urolithiasis. The use of UAS should be considered to decrease the risk of infectious complications, particularly in those who may be at higher risk for such complications.

Bidirectional Impact of Varying Severity of Acute Kidney Injury on Calcium Oxalate Stone Formation

INTRODUCTION

Acute kidney injury (AKI) is a prevalent renal disorder. The occurrence of AKI may promote the formation of renal calcium oxalate stones by exerting continuous effects on renal tubular epithelial cells (TECs). We aimed to delineate the molecular interplay between AKI and nephrolithiasis.

METHODS

A mild (20 min) and severe (30 min) renal ischemia-reperfusion injury model was established in mice. Seven days after injury, calcium oxalate stones were induced using glyoxylate (Gly) to evaluate the impact of AKI on the formation of kidney stones. Transcriptome sequencing was performed on TECs to elucidate the relationship between AKI severity and kidney stones. Key transcription factors (TFs) regulating differential gene transcription levels were identified using motif analysis, and pioglitazone, ginkgetin, and fludarabine were used for targeted therapy to validate key TFs as potential targets for kidney stone treatment.

RESULTS

Severe AKI led to increased deposition of calcium oxalate crystals in renal, impaired kidney function, and upregulation of kidney stone-related gene expression. In contrast, mild AKI was associated with decreased crystal deposition, preserved kidney function, and downregulation of similar gene expression. Transcriptomic analysis revealed that genes associated with inflammation and cell adhesion pathways were significantly upregulated after severe AKI, while genes related to energy metabolism pathways were significantly upregulated after mild AKI. An integrative bioinformatic analysis uncovered a TF regulatory network within TECs, pinpointing that PKNOX1 was involved in the upregulation of inflammation-related genes after severe AKI, and inhibiting PKNOX1 function with pioglitazone could simultaneously reduce the increase of calcium oxalate crystals after severe AKI in kidney. On the other hand, motif analysis also revealed the protective role of STAT1 in the kidneys after mild AKI, enhancing the function of STAT1 with ginkgetin could reduce kidney stone formation, while the specific inhibitor of STAT1, fludarabine, could eliminate the therapeutic effects of mild AKI on kidney stones.

CONCLUSION

Inadequate repair of TECs after severe AKI increases the risk of kidney stone formation, with the upregulation of inflammation-related genes regulated by PKNOX1 playing a role in this process. Inhibiting PKNOX1 function can reduce kidney stone formation. Conversely, after mild AKI, effective cell repair through upregulation of STAT1 expression can protect TEC function and reduce stone formation, and activating STAT1 function can also achieve the goal of treating kidney stones.

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.

Utilization of Ureteral Access Sheath in Retrograde Intrarenal Surgery: A Systematic Review and Meta-Analysis

Background and Objectives: This paper evaluates the efficacy and safety of ureteral access sheath (UAS) utilization in retrograde intrarenal surgery (RIRS). Materials and Methods: We searched PubMed, Embase, and the Cochrane Library up to 30 August 2023. The inclusion criteria comprised English-language original studies on RIRS with or without UAS in humans. The primary outcome was SFR, while the secondary outcomes included intraoperative and postoperative complications, the lengths of the operation and the hospitalization period, and the duration of the fluoroscopy. Subgroup analyses and a sensitivity analysis were performed. Publication bias was assessed using funnel plots and Egger's regression tests. Dichotomous variables were analyzed using odds ratios (ORs) with 95% confidence intervals (CIs), while mean differences (MDs) were employed for continuous variables. Results: We included 22 studies in our analysis. These spanned 2001 to 2023, involving 12,993 patients and 13,293 procedures. No significant difference in SFR was observed between the UAS and non-UAS groups (OR = 0.90, 95% CI 0.63-1.30, p = 0.59). Intraoperative (OR = 1.13, 95% CI 0.75-1.69, p = 0.5) and postoperative complications (OR = 1.29, 95% CI 0.89-1.87, p = 0.18) did not significantly differ between the groups. UAS usage increased operation times (MD = 8.30, 95% CI 2.51-14.10, p = 0.005) and fluoroscopy times (MD = 5.73, 95% CI 4.55-6.90, p < 0.001). No publication bias was detected for any outcome. Conclusions: In RIRS, UAS usage did not significantly affect SFR, complications, or hospitalization time. However, it increased operation time and fluoroscopy time. Routine UAS usage is not supported, and decisions should be patient-specific. Further studies with larger sample sizes and standardized assessments are needed to refine UAS utilization in RIRS.

Predictive factors for difficult ureter in primary kidney stone patients before retrograde intrarenal surgery

Introduction

Ureter may be resistant to insertion of ureteral access sheath (UAS) and/or semi-rigid ureterorenoscope because of the narrow ureter, 'difficult ureter' especially in primary retrograde intrarenal surgery (RIRS) cases. We aimed to delineate the parameters that affect significantly the accessibility of the ipsilateral ureter of the stone-bearing patient side.

Material and methods

The data of age, gender, body mass index, comorbidities, prior urinary tract infection, prior stone passage, stone burden, stone density, number of stones, stone localization, surgery side, the presence of hydronephrosis and need for double J (DJ) stent due to difficult ureter for all patients were reviewed. Difficult ureter was defined as the insertion inability of a semi-rigid ureterorenoscope or UAS into the ureter at the surgery side. All patients were divided into two groups as difficult ureter group and non-difficult ureter group.

Results

A total of 454 patients who underwent RIRS for primary kidney stones were included. The incidence of difficult ureter was 7.5% (34/454). The patients in the difficult ureter group were younger. Female gender and prior urinary tract infection rates were higher in the difficult ureter group. Multivariate logistic regression analysis indicated that the factors significantly associated with higher odds of having a difficult ureter in primary RIRS patients were younger age (OR 1.040; 95% CI 1.010-1.070; p = 0.008), female gender (OR 2.859; 95% Cl 1.383-5.908; p = 0.005) and prior urinary tract infection (OR 3.327; 95% CI 1.230-8.999; p = 0.018).

Conclusions

Difficult ureter was associated with younger age at the time of RIRS, female gender and the manifestation of urinary infections in the patient's medical history.

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

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

Multicentric evaluation of high and low power lasers on RIRS success using propensity score analysis

In this study, we aimed to evaluate the effect of HPL on different parameters by different centers and urologists. While doing this, we evaluated different parameters by comparing HPL(High Power laser) and LPL(Low-power laser). This is an observational, retrospective, comparative, multicentric study of prospectively organised database. A total of 217 patients who underwent RIRS for kidney stones smaller than 2 cm in three different centers were included in the study. The patients were divided into two groups; LPL used (Group1, n:121 patients) and HPL used (Group2, n:96). Propensity score matching was done in the data analysis part. After matching, a total of 192 patients, 96 patients in both groups, were evaluated. There was no difference between the groups regarding age, gender, stone side, and stone location. The stone-free rate on the first day was 80.3% in Group 1, it was 78.1% in Group 2 (p = 0.9). In the third month, it was 90.7% in Group 1 and 87.5% in Group 2 (p:0.7).Hospitalization duration was significantly higher in Group 1. (2.35 ± 2.27 days vs. 1.42 ± 1.10 days; p < 0.001).The operation duration was 88.70 ± 29.72 min in Group1 and 66.17 ± 41.02 min in Group2 (p < 0.001). The fluoroscopy time (FT) was 90.73 ± 4.79 s in Group 1 and 50.78 ± 5.64 s in Group 2 (p < 0.001). Complications according to Clavien Classification, were similar between the groups(p > 0.05). According to our study similar SFR and complication rates were found with HPL and LPL. In addition, patients who used HPL had lower operation time, hospital stay, and fluoroscopy time than the LPL group. Although high-power lasers are expensive in terms of cost, they affect many parameters and strengthen the hand of urologists thanks to the wide energy and frequency range they offer.

The Effect of Ureteral Access Sheath Use/Caliber Change on Outcomes of Retrograde Intrarenal Surgery, Short-Term Kidney Functions, Radiation Exposure, Ureteroscope Lifetime, and Factors Predicting Insertion Failure: A RIRSearch Study

Background: The aim of this study was (1) to explore effect of ureteral access sheath (UAS) use on primary retrograde intrarenal surgery (RIRS) outcomes, short-term kidney functions, radiation exposure, and ureteroscope lifetime (URS-LT) and (2) to reveal factors that predict UAS insertion failure. Materials and Methods: Patients (n = 1318) who underwent RIRS without UAS (Group 1), those who had operation with a <11-13 Fr (Group 2), and those with a ≥11-13 Fr UAS were matched (1:1:2) and compared. Stone-free rate (SFR), intra- and postoperative complications, acute kidney injury (AKI), fluoroscopy time, URS-LT, and UAS insertion failure were the outcomes. Results: SFR, which was highest in Group 3 (75%, 71% and 87.3%, respectively; P = .001), was significantly associated with use of ≥11-13 Fr (odds ratio [OR]: 4.2, P < .001), but was not with use of <11-13 Fr UAS (OR: 1.3, P = .3). Group 3 had less need for auxiliary procedure (15%, 16%, and 7.4%, respectively; P = .03). Five percent of patients had a risk of AKI, but only 0.3% developed AKI. Although UAS use was protective against creatinine increase (OR: 0.65, P = .02), increased risk of AKI was only associated with female gender (OR: 5.5, P < .001). Fluroscopy times were 5, 15, and 87 sn, respectively (P < .001). Short URS-LT was strongly associated with high frequency of lower calix stones (r = -0.94, P = .005), but URS-LT was not correlated with sheathless case rate (r = 0.59, P = .22). UAS insertion success in first attempt was more likely in younger (OR: 0.99, P = .03), hydronephrotic (OR: 3.4, P < .001), and female cases (OR: 1.5, P = .008). But absolute UAS insertion failure was associated with female gender (OR: 2.7, P = .017). Conclusions: Not any UAS use but a higher caliber UAS use may improve SFR and protect against AKI after RIRS. Although UAS insertion failure is seen mostly in men, it may be more challenging in women owing to less efficacy of preoperative Double-J stent.