Morbidity and impact on quality of life in patients with indwelling ureteral stents: A 10-year clinical experience

Role of ureteral stent material and coating to prevent ureteral stent related issue: A systematic review and meta analysis

INTRODUCTION

Ureteral stents require materials that balance bulk and surface properties. Achieving both can be challenging, as ideal bulk properties may not align with optimal surface properties. Thus, researching coatings and biomanufacturing methods for ideal materials is essential.

METHODS

A systematic review and meta-analysis, following PRISMA Guidelines, involved literature searches across five databases: PubMed, Scopus, Embase, ClinicalKey, and Cochrane. From 417 screened articles, eight studies were deemed eligible for qualitative and quantitative analysis. The selected articles underwent bias assessment using ROB Tools 2.

RESULTS

The systematic review analyzed 1.356 participants. Findings revealed that firm ureteral stents significantly increased risk of infection, hematuria, and lower body pain. On the contrary, soft stents reduced infection (OR: 0.62; p=0.004), hematuria (OR: 0.60; p<0.001), and lower body pain (OR: 0.63; p=0.0002). However, infection reduction effect was uncertain due to heterogeneity. Coated vs non-coated material analysis found no difference in encrustation (OR: 1.26; p=0.52) or infection (OR: 1.67; p=0.99). Stent firmness did not affect encrustation on double J stent (OR: 0.97; p=0.17).

CONCLUSIONS

Softer materials like silicone are preferred for ureteral stents to reduce symptoms like hematuria and lower body pain. Coatings like silver nanoparticles and triclosan, while enhancing antimicrobial properties, did not effectively lower infection risk.

Comparison of the Removal Efficiency and Safety of Magnetic Versus Conventional Ureteral Stents: A Systematic Review and Meta-analysis

Context

The incidence of urolithiasis is increasing year by year. Ureteral stents are a popular treatment option for this condition. Efforts to improve the material and structure of stents to increase comfort and reduce complications have led to the introduction of magnetic stents.

Objective

To evaluate differences in removal efficiency and safety for magnetic and conventional stents.

Evidence acquisition

This study was conducted and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Data were extracted according to the PRISMA principles. We collected and combined data from randomized controlled trials on magnetic versus conventional stents to evaluate the efficiency of their removal and the associated effects. Data synthesis was performed using RevMan 5.4.1 and heterogeneity was evaluated using I² tests. A sensitivity analysis was also performed. Key metrics included the stent removal time, Visual Analog Scale (VAS) pain scores, and Ureteral Stent Symptom Questionnaire (USSQ) scores for various domains.

Evidence synthesis

Seven studies were included in the review. We found that magnetic stents had a shorter removal time (mean difference [MD] -8.28 min, 95% confidence interval [CI] -15.6 to -0.95; p = 0.03) and their removal was associated with less pain (MD -3.01 points, 95% CI -3.83 to -2.19; p < 0.01) in comparison to conventional stents. USSQ scores for urinary symptoms and sexual matters were higher for magnetic than for conventional stents. There were no other differences between the stent types.

Conclusions

Magnetic ureteral stents have the advantages of a shorter removal time, less pain during removal, and low cost in comparison to conventional stents.

Patient summary

For patients undergoing treatment of urinary stones, a thin tube called a stent is often temporarily inserted in the tube between the kidney and the bladder to allow stones to pass. Magnetic stents can be removed without any need for a second surgical procedure. Our review of studies comparing two types of stents suggests that magnetic stents are superior to conventional stents in terms of efficiency and comfort during removal.

Mussel-Inspired Clickable Antibacterial Peptide Coating on Ureteral Stents for Encrustation Prevention

Long-term indwelling catheters or stents often cause complications like infection, encrustation, hematuria, pain, and so on. The source of these problems is bacteria, which can form biofilms on the stents to reduce antibiotic sensitivity and produce urease to form encrustation by increasing the urine pH. Urinary tract infection (UTI) can aggravate the body damage and even seriously endanger lives, and the encrustation will block the stents, which can cause hydronephrosis and renal function damage. Therefore, the prevention of UTI and encrustation represents a great challenge in clinical ureteral stent uses. In this work, a clickable mussel-inspired peptide and antimicrobial peptide (AMP) were used to functionalize the commercial stents' surfaces to inhibit long-term infection and encrustation caused by bacteria. Copper (Cu) ions were used to coordinate the mussel-inspired peptide to improve the stability. The AMP with an azido group was clicked to the mussel-inspired Cu-coordinated peptide coating through click chemistry. The bio-inspired antibacterial coating was constructed with excellent stability, bactericidal properties, and improved biological compatibility. In in vitro and in vivo experiments, it was further found that the coating showed bactericidal and encrustation reduction abilities. This study thus developed an effective, safe, and stable AMP coating on urinary stents/catheters capable of long-term antibacterial and encrustation inhibition.

Utility of Post-ureteroscopy Lesion Scale (PULS) in Per-operative Decision-Making for the Need of Double J Stent

Objectives: To assess the applicability of the post ureteroscopy lesion scale (PULS) as an objective measure to define the need for double J (DJ) stent placement after ureterorenoscopy (URS).

Methods: Between June and December 2020 a cross-sectional study was conducted at a university hospital. All patients fulfilling the inclusion criteria undergoing URS for renal or ureteric stones were included. At the completion of procedures, the ureter was carefully inspected for injury. Lesions were classified using PULS scoring by the operating surgeon, another consultant, and the resident. The primary outcome was to validate the PULS score against the surgeon’s decision for postoperative stenting and to assess its reliability. 

Results: A total of 126 patients were included with a mean age of 43.42±15.3 years. The mean stone size was 9.42±3.60mm. DJ stents were placed in 81 cases (62.4%). All of the 38 (30.1%) patients with a significant residual fragment were stented. Ureteric injury of grade 1 was observed in 66 patients (52.3%), of which 22 (33%) had DJ stenting. PULS grade 2 injuries were observed in 22 patients (17.4%), and 95% were stented. With a PULS score of > 2 almost all (97.8%) were stented. Inter-rater reliability of PULS scoring was high among the consultants (Kendall’s W=0.89, p<0.005).

Conclusion: DJ stent placement was observed in 33%, 95%, and 98% of patients with PULS grade 1, 2, and >2 injury respectively. In patients with no residual fragment, the need for DJ stenting can be objectively defined using the PULS scoring system as it has high specificity and good interrater reliability.

Complete intraureteral stent placement relieves daytime urinary frequency compared with conventional placement in patients with an indwelling ureteral stent: post-hoc analysis of a randomized, controlled trial

A previous randomized, controlled trial had demonstrated that complete intraureteral stent placement (CIU-SP) was superior to conventional stent placement (C-SP) in terms of improvement of stent-related urinary symptoms. However, it is unclear as to which subdomain symptom and cohort could benefit the most from CIU-SP compared to C-SP in urinary symptoms while considering the baseline urinary status. To determine this, a post-hoc analysis was performed using data from a previous study (CIU-SP group, n = 39; C-SP group, n = 41). We assessed the mean changes in the International Prostate Symptom Score (I-PSS) and the Overactive Bladder Symptom Score (OABSS) from baseline to day 14. Statistical comparison between the two groups was performed using analysis of covariance with adjustment of baseline urinary status as a covariate. Among 80 patients, the total I-PSS was significantly lower in the CIU-SP group than in the C-SP group in the cohort with mild urinary symptoms (P = 0.005), but not in those with moderate/severe symptoms (P = 0.521). The CIU-SP group showed significantly improved I-PSS and OABSS daytime frequencies, with the highest t statistic (2.47 and 2.10, respectively) among subdomains of both symptom scores compared with the C-SP group (both P < 0.001). In multivariate regression analysis, the stent placement method (CIU-SP vs. C-SP) was independently associated with the I-PSS daytime frequency on day 14 (P = 0.017). This study suggests that CIU-SP significantly improved stent-related daytime frequency compared with C-SP, and it may benefit especially those patients who have mild urinary symptoms before the placement of ureteral stents.

Fluoroscopy-free double-J stent placement through ureteroscope working channel postuncomplicated ureteroscopic laser lithotripsy: A novel technique

Objectives:

To report a technique for ureteroscopic laser lithotripsy (URSL) and retrograde placement of a double-J (DJ) stenting through the ureteroscope working channel without the use of a fluoroscope compared to the conventional technique.

Patients and Methods:

Between June 2015 and December 2017, 170 patients selected for URSL for treatment of ureteral stones and DJ insertion was evaluated. Patients are divided into two groups according to the use of fluoroscopy. In Group A (100 patients), fluoroscope is used and group B (70 patients) without fluoroscopy guidance. In group B, URSL is performed first and followed by DJ insertion by the semi-rigid ureteroscope 8.5-11 Fr under vision without fluoroscopy.

Results:

Stone free rate in 96% versus 94.3% for groups A and B respectively. This technique was successful in all the included patients: 166 retrograde DJ stenting post URSL for ureteric calculi and 4 cases for anuria. Group A are exposed to radiation with mean 26.6 seconds in URSL procedure and 4.8 seconds for DJ stenting. Group B was exposed to zero dose. For group A, the stents size was 6 Fr for 70% of patients and 15 % for 4.7 Fr and 15% for 7 Fr stenting. In Group B, stents of 4.7 Fr and length 24-26 cm were used in all patients. Failure of DJ insertion is reported in 9% for group A and 13 (18.5%) patients for group B.

Conclusions:

This study report the feasibility and efficacy of the completely fluoroscopy free URSL and DJ stenting to treat ureteric stones.

Advances in Ureteral Stent Design and Materials

Purpose of Review

There are three technological parameters that play a key role on the performance of an ideal stent. These are its material, design and surface coating. This article highlights some fundamental developments that took place in these three areas of stent’s technology, in order to contribute to the identification of an ideal stent.

Recent Findings

In addition to technological developments concerning stent’s material, design and surface coating, the flow dynamic performance of stents has recently attracted increasing attention. Notably, it has been postulated that the local flow field in a stent is correlated with the deposition of crystals and microorganisms. These findings could potentially revolutionise future stent’s designs, and complement developments made on materials and coatings.

Summary

The most relevant changes in materials, designs and surface coatings of ureteric stents are reviewed in this article. These are described in the context of a specific cause of stent’s failure they aim to address, with a particular focus on encrustation and biofilm formation.