In Vivo Evaluation of a Novel Pigtail Suture Stent

Outcomes of a non-randomised audit of single pigtail suture stents in urolithiasis management of Asian patients in Singapore

Objective

Double-J (DJ) ureteric stents are commonly placed perioperatively for semirigid or flexible ureteroscopic renal surgery. It is believed that lesser stent material within the bladder mitigates stent-related symptoms. This study aimed to evaluate the J-Fil ureteral stent, a single pigtail suture stent compared with conventional DJ stent in relation to stent symptoms in an Asian population undergoing ureterorenal intervention.

Methods

Based on internal audit committee recommendation approval, the records of 50 patients retrieved, available data of 41 patients who were prospectively enrolled into two groups (Group 1 [J-Fil stent group], n=21 and Group 2 [DJ stent group], n=20) between August 2020 to January 2021, were analysed. Parameters compared were nature of procedure, stone location and size, ease of deployment or removal, and complications. A modified universal stent symptom questionnaire was used to assess morbidity of stent symptoms within 48 h of insertion and at removal.

Results

Both groups had similar median age, distribution in male to female ratio, and stone size. The overall median universal stent symptom questionnaire score at insertion was similar for bladder pain, flank or loin pain, and quality of life between Group 1 and 2; however, at removal Group 1 fared significantly better than Group 2, especially for flank or loin pain and pain at voiding. Both groups had similar ease in insertion with no hospital readmissions.

Conclusion

Our audit favoured the single pigtail suture stent in Asian ureters in mitigating stent-related issues. It showed a good safety profile with easy deployment and removal. It promises a new standard in stenting.

Comparation of intraureteral stent and conventional stent at different stages: a systematic review with meta-analysis

INTRODUCTION

Stent related symptom (SRS) is the most common adverse effect of ureteral stenting. In recent years, many efforts have been made to develope modified ureteral stents to ameliorate SRS. It has been reported that intraureteral stents have the potential to improve the tail end adverse effect of the bladder and alleviate SRS. However, there still lack of evidence for the efficacy and the safety of clinically applying intraureteral stents. The aim of this work is to investigate the efficacy and safety of intraureteral stents.

EVIDENCE ACQUISITION

A systematic review was performed by using the PubMed, Web of Science, Medline, Embase, and Cochrane library. The studies published before February 2023 were included. The study selection was following the guideline from Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). The searching strategy was: "Pigtail suture stent" OR "Intra-ureteric stent" OR "Suture Stent" OR "Intraureteral stent" AND "Ureteroscopy" OR "Urinary calculi" OR "Stent-related symptoms" OR "Lower urinary tract symptoms". The data from randomized clinical trials which meet the selection criteria were extracted. Revman 5.4 was employed to proceed the meta-analysis.

EVIDENCE SYNTHESIS

A total of six randomized clinical trials of intraureteral stents were included in this systematic review and meta-analysis. According to the different investigation time, the results could be divided into four stages: early-stage, middle-stage, late-stage, and long-term evaluation. Urinary symptoms, pain score, and general health were significantly improved in intraureteral stents group at middle stage. For late-stage, intraureteral stent achieved better outcomes in urinary symptoms index, VAS score, quality of life, general health, and pain score. However, for early-stage and long-term evaluation, there was no significant difference between two groups.

CONCLUSIONS

This systematic review and meta-analysis reveal that regardless of the stage of treatment, the efficacy and safety of intraureteral stent are no worse than that of conventional stent. During 7-14 days postoperation, which is the most commonly time for clinically using ureteral stent, most of the outcomes of intraureteral stent are better than those of conventional stent. Hence, it is confirmed that intraureteral stent is worth for more clinical study and application.

Indwelling stents cause severe inflammation and fibrosis of the ureter via urothelial-mesenchymal transition

To explore the pathways and mechanisms driving inflammation and fibrosis in stented ureters. In total, six healthy female pigs underwent cystoscopic unilateral ureteral stent insertion (6 Fr). After 14 days indwelling time, ureteral tissue was harvested in three pigs, while the remaining three pigs had their stents removed, and were recovered for 7 days. Three separate pigs served as controls. Tissue from stented and contralateral ureters was analysed histologically to evaluate tissue remodelling and classify the degree of inflammation and fibrosis, while genome, proteome and immunohistochemistry analysis was performed to assess changes at the transcriptional and translational levels. Finally, immunofluorescence was used to characterize the cell composition of the immune response and pathways involved in inflammation and fibrosis. Statistical analysis was performed using GraphPad Prism and RStudio for Welch ANOVA, Kruskal-Wallis and Dunnett's T3 multiple comparison test. Stents cause significant inflammation and fibrosis of ureters. Gene set enrichment analysis confirmed fibrotic changes and tissue proliferation and suggests that epithelial-mesenchymal transition is a driver of fibrosis. Moreover, IL-6/JAK/STAT and TNFα via NF-κB signalling might contribute to chronic inflammation promoting a profibrotic environment. Immunostaining confirmed epithelial-mesenchymal transition in the urothelium and NF-κB expression in ureters stented for 14 days. Tissue alterations do not fully recover after 7 days. Histological evaluation showed that contralateral, unstented ureters are affected by mild inflammation. Our study showed that stenting has a significant impact on the ureter. Chronic inflammation and epithelial-mesenchymal transition are drivers of fibrosis, potentially impairing ureteral functionality in the long term. Furthermore, we observed mild inflammation in contralateral, unstented ureters.

Advances in ureteral stent technology

PURPOSE OF REVIEW

Ureteral stents are an invaluable tool for urologists but suffer from several drawbacks, including: limited durability due to stent encrustation, significant morbidity from bothersome urinary symptoms, pain and infection, risk of the forgotten stent and costly removal. This review highlights key advances in ureteral stent technology that seek to address these issues.

RECENT FINDINGS

Over the past 2 years clinical trials have brought ureteral stent technology aimed to reduce stent-associated morbidity closer to clinical application. Stent material and changes to stent design show promise in improving patient tolerability without increasing complications. Low-tech innovations such as magnetic and catheter snare removal may quickly reduce costs. Radical advances such as biodegradable stent materials remain in preclinical models but show promise for eliminating the need for stent removal.

SUMMARY

The ideal ureteral stent does not currently exist in clinical practice. This review highlights key studies that have advanced ureteral stent technology in the past 2 years.

Developments in Ureteral Stent Technology

Ureteral stents have been utilized for decades in maintaining ureteral patency, most commonly after ureteroscopy in the treatment of urolithiasis. Since their initial development, ureteral stents have had many technological advances that have allowed for better patient outcomes with improvements in comfort, durability, patency, encrustation resistance, biocompatibility, ease of insertion, migration, and biofilm development. Several new ureteral stents enter the market every year, each with their own touted benefits. It is essential to understand the different advantages for each ureteral stent to provide the best available care to patients when possible. The purpose of this review is to give a brief history of ureteral stent development and summarize the recent developments in ureteral stent designs. We aim to review the data supporting the clinical advantages of the latest ureteral stents available for use by urologists.

New Stent Technologies

Ureteral stents are an indispensable part of any (endo-) urologic practice. Despite the widely demonstrated advantages of stents, they also carry a considerable risk of side effects and complications, such as urinary symptoms, pain, hematuria, decreased quality of life, stent-related infection, and encrustation. Multiple pathways in preventing or mitigating these side effects and complications and improving stent efficacy have been and are being investigated, including stent architecture and design, biomaterials, and coatings. This article provides an update on currently researched and available stents as well as future perspectives.

10-Year Experience with Reinforced Ureteral Stents for Malignant Ureteral Obstruction

Introduction

Malignant ureteral obstruction (MUO) hinders the management of malignant diseases. Indwelling stent is a common method to release renal obstruction, but stent failure with obstruction is frequent. The studies conclude that stent obstruction divides survival by 2 or even 4. We carried out the present study in order to evaluate drainage efficiency and overall survival by using stents with distinctive degrees of stiffness.

Materials and Methods

We performed an analysis of 156 patients with MUO drainage at a single institution from June 2009 to June 2019.

Results

Of the 156 patients, 128 (82.1%) died with a mean survival time of 15.3 ± 14.4 months after the first ureteral stent procedure (USP). In order to study stent failure and overall survival, the patients were divided into 3 groups. Group 1 with patients died soon after only one USP (n=37). Group 2 with patients had more than one USP and no obstruction (n=41). Patients in Group 3 had more than one USP and at least one stent obstruction (n=62). During the study period, 556 USPs were analysed separately. The stent failure with obstruction occurred in 23.0% (128/556) of USP at a mean of 4.4 ± 3.6 months. In case of stent failure, a progressive choice of stents was shaped to overcome each failure by focusing on the criterion of increasingly stiff stents. Patients in Group 1 died soon at mean of 4.9 ± 4.8 months. The mean survival time of patients in Groups 2 and 3 were, respectively, 19.4 ± 11.2 and 21.5 ± 16.3 months (P = 0.19).

Conclusion

MUO is a serious disease but this study is the first to prevent survival rate from falling by choosing the stent stiffness suitable for the patient. The active detection of stent failure has been shown to be essential for preserving survival.

Characterization of Sonic Hedgehog/Gli1 Signal Expression in Human Ureter Either Un-Stented or Fitted with Double-Pigtail Stent or a Thread

Introduction

The Sonic Hedgehog/Gli1 signal is involved in smooth muscle activity. An experiment showed that the double-pigtail stent caused ureteral inflammation and decreased Gli1 expression in smooth muscle cells. The innovative pigtail-suture stent (JFil^® or MiniJFil^®) with a thin 0.3F suture thread significantly decreased stent-related symptoms. Fortuitously, a dilation of the ureter containing the sutures was discovered, and a previous study confirmed that the sutures caused less ureteral inflammation than the double-pigtail stent. However, the mechanisms involved in the ureteral dilation are still unknown. In this study, we assessed ureteral Gli1 expression in the human ureter when it was un-stunted or when fitted with a double-pigtail stent or a suture thread.

Material and Methods

After consent and inclusion of patients in the protocol, nine segments of ureters were collected during cystectomy procedures for bladder cancers. There was no selection or exclusion, and patients with large tumors were included. Gli1 expression was assessed on the histological section to control the reflection of an active hedgehog signal. The expression of Gli1 in smooth muscle cells of the stented ureter was subjectively compared to un-stented ureter.

Results

A decrease in the intensity of Gli1 expression of smooth muscle cells was observed in all cases of ureter fitted with a double-pigtail stent. For the un-stunted ureters and the ureters fitted with the thin 0.3F suture thread, Gli1 staining of smooth muscle cells was heterogeneous, and the small number of cases did not allow us to conclude.

Conclusion

Apart from the cases of ureters fitted with the double-pigtail stent, Gli1 expression of smooth muscle was heterogeneous. The Shh/Gli1 pathway may not be involved in ureteral dilation by the thread. A broader exploration of molecular mechanisms could make it possible to obtain the mechanisms involved in the dilation of the ureter by the thread.

Pigtail Suture Stents Significantly Reduce Stent-related Symptoms Compared to Conventional Double J Stents: A Prospective Randomized Trial

BACKGROUND

Double J (DJ) ureteral stents are commonly inserted after ureteroscopy (URS) procedures for stone treatment. However, stent-related symptoms are still a major issue.

OBJECTIVE

To determine whether a commercially available pigtail suture stent (PSS) can reduce stent-related symptoms compared to a conventional DJ stent after uncomplicated URS.

DESIGN SETTING AND PARTICIPANTS

We designed a randomized, single-blind, parallel-group trial from January to November 2020. The inclusion criteria were stone-free URS without intraprocedural complications. Patients with distal ureteral stones were excluded.

INTERVENTION

Insertion of a PSS or DJ stent after URS.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was the Urinary Symptom Index score on the Ureteral Stent Symptoms Questionnaire (USSQ) 2 wk after URS. Secondary endpoints were USSQ domain scores and responses to individual USSQ questions at 2 d and 2 wk after surgery.

RESULTS AND LIMITATIONS

A total of 78 patients were randomized and treated according to protocol. The Urinary Symptom Index score (p = 0.004), overall Visual Analogue Scale (VAS) score (p = 0.022), and the percentage of patients complaining of pain (63.9% vs 86.1%, p = 0.029) were significantly in favor of PSS at both 2 d and 2 wk after URS. At 2 d, the VAS score among patients with pain (p = 0.025) and the General Health Index score (p = 0.036) were significantly better in the PSS group. No severe complications occurred in either group. Study limitations are the exclusion of patients with distal ureteral stones and the limited sample size.

CONCLUSIONS

PSS significantly reduced stent-related symptoms after URS, in particular urinary symptoms and pain, compared to conventional DJ stents, and showed a good safety profile.

PATIENT SUMMARY

Stents are hollow tubes placed in the passage between the kidney and the bladder (ureter). The standard stent has two coiled ends (double J stent) to keep it in place in both the kidney and the bladder. We tested a commercial stent with two strings at the bladder end (pigtail suture stent) after procedures to remove stones from the upper urinary tract and found that it caused less stent-related symptoms compared to a double J stent.

This trial is registered at Clinicaltrials.gov as NCT03344120.