Ureteral stent obstruction and stent's discomfort are not irreparable damages

Antireflux Ureteral Stents Prevent Stent-Related Symptoms: A Meta-Analysis of Randomized Controlled Trials

Ureteral stents are widely used in urological care, but they are often associated with adverse stent-related symptoms (SRS), such as painful urination, elevated urinary frequency, and abdominal discomfort. Antireflux ureteral stents have been developed to reduce stent-related pain and reflux by minimizing vesicoureteral reflux (VUR). This systematic review and meta-analysis of randomized controlled trials (RCTs) was undertaken to assess the efficacy of antireflux ureteral stents in mitigating SRS compared to conventional urethral stents. Our study included a total of 269 cases from three RCTs. The meta-analysis showed that antireflux ureteral stents were significantly more effective than standard stents in reducing SRS, including stent-related pain (odds ratio (OR): 4.80, 95% CI: 2.77, 8.31, p <0.00001), severe stent-related pain (OR: 8.35, 95% CI: 2.12, 32.89, p=0.002), flank pain while urinating (OR: 5.98, 95% CI: 3.35, 10.68, p <0.00001), and severe flank pain while urinating (OR: 15.79, 95% CI: 2.91, 85.57, p=0.001). There was no significant difference in the rates of postoperative creatinine abnormality or postoperative hydronephrosis between the two groups. Therefore, antireflux ureteral stents are more effective than standard stents in reducing SRS. This suggests that antireflux ureteral stents should be considered for patients undergoing ureteral stenting.

Allium ureteral stent for the treatment of malignant ureteral obstruction: A median term study

This study aimed to assess the safety and efficacy of Allium ureteral stents for the maintenance therapy of malignant ureteral obstruction (MUO). Clinical data of 25 patients (27 sides) with ureteral obstruction caused by a malignant tumor from December 2018 to December 2021 were retrospectively analyzed. Preoperative ultrasonography and computed tomography urography indicated hydronephrosis and MUO. Allium ureteral stents were placed using a retrograde or antegrade approach. Therapeutic effects and complications were recorded. The Wilcoxon signed-rank test was used to compare continuous variables between the preoperative and the last follow-up. A total of 25 patients (27 sides) were included in this study. After a follow-up time of 18 (11-29) months, the width of hydronephrosis [1.6 (1.0-2.2) cm vs 2.6 (1.2-3.3) cm, P = .000], glomerular filtration rate [83.8 (58.1-86.4) mL/minutes/1.73 m2 vs 74.5 (56.8-79.1) mL/minutes/1.73 m2, P = .001] and score of ureteral stent symptoms questionnaire [77 (76-79) vs 100 (98-103), P = .000] was significantly improved. Stent migration occurred in 3 of the 25 patients within 3 months after surgery. All patients with complications were followed up for at least 6 months after stent adjustment or exchange, and no other complications were found. Two patients died because of malignant complications. The stent patency rate was 88.9% (24/27) after the first operation, and 100% (27/27) after complications were treated. The Allium ureteral stent is safe and effective for the maintenance therapy of MUO, which can dramatically relieve the symptoms of patients. Stent migration is a major complication that can be resolved by endoscopic adjustment.

Analysis of Ureteral Tumour Stents for Malignant Ureteral Obstruction: Towards Reshaping an Optimal Stent

Introduction

Ureteral obstruction hinders the management of malignant diseases. Adequate stent placement does not necessarily guarantee renal decompression. The stent stiffness may play a major role to maintain patency. We carried out the present study in order to evaluate drainage efficiency by using stents with distinctive degrees of stiffness and to identify the physical factors that could prevent obstruction of the stent in patients with malignant ureteral obstruction (MUO).

Materials and Methods

We performed an analysis of 150 patients with MUO drainage at a single institution from June 2009 to June 2019. A progressive choice of stents was shaped to overcome each failure by focusing on the criterion of increasingly stiff stents.

Results

During the study period, 556 ureteral stent procedures (USP) 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 and depended on the type of stent. Stent failure occurred in 34.2% (70/205) of Vortek^® stents, in 42.9% (15/35) of Urosoft stents, in 15.4% (39/254) of Superglide or ureteral catheters and in 6.5% (4/62) of tandem stents. No significant differences were found between Vortek^® and Urosoft stents regarding stent failures, but there were significant differences between Superglide or Tandem stents and Vortek^® or Urosoft stents (p<10⁻⁷). The study demonstrated that ureteral stent obstruction significantly decreased with a larger lumen or a stiffer stent (p<10⁻⁷).

Conclusion

In the present study, Superglide and tandem stents were the best stents against stent failure, and the lumen and the stiffness of the stent have been shown to be critical factors in controlling patency. The results suggest that the lumen seems more important than the stiffness, and the stiffness would be the only means of keeping the lumen intact. Future stents for MUO should integrate the importance of the lumen of the stent.

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.

Stiffness Analysis of Reinforced Ureteral Stents Against Radial Compression: In vitro Study

Introduction

Malignant ureteral obstruction caused by cancer diseases may induce renal failure. Indwelling stent is a popular method to release renal obstruction. But adequate stent placement across an obstructed ureter does not necessarily guarantee renal decompression. The aim of the study was to compare, in vitro, the physical characteristics and stiffness of several commercially available reinforced ureteral stents and identify the physical factors that could lead to the obstruction of the stent.

Material and Methods

The test apparatus used for measurements allowed applying a radial compression force on a segment of the stent to stop a water flow through the lumen of the stent. Some reinforced double-pigtail stents Teleflex Medical, Bard, and Coloplast were evaluated.

Results

The best physical-stiffness characteristic was obtained with the Teleflex 8F stent (5.4 N mm⁻²). The best result against the radial compression was obtained with tandem stents. The radial compressive stresses of the Teleflex stents (4.4 to 5.4 N mm⁻²) were higher than with the other stents used in the study (1.0 to 2.9 N mm⁻²). Among the reinforced stents selected in the present study, a wider inner diameter helped increase volumetric flow rate but did not affect the stiffness of the stent. The measurement of inner diameter showed heterogeneity along the tube of some stents.

Conclusion

The stiffness of the stent appeared to be an important factor to maintain patency with respect to radial compression forces but the inner diameter of the stent and its preservation may be essential parameters to increase the volumetric flow rate. Some reinforced stents tested in the present study confirmed that it is possible to combine stiffness and wide lumen. The use of tandem stents provided the best stiffness against radial compression and the greatest lumen.

Management and treatment options when facing malignant ureteral obstruction

Malignant ureteral obstruction is an unfortunate finding that can be caused by a wide-ranging number of malignancies with a prognosis of limited survival. Given its presentation and progression, it can be refractory to treatment by traditional single polymeric ureteral stents. With a higher failure rate than causes of benign ureteral obstruction, a number of other options are available for initial management, as well as in cases of first-line therapy failure, including tandem stents, metallic stents, percutaneous nephrostomies and extra-anatomic stents. We reviewed the literature and carried out a PubMed search including the following keywords and phrases: "malignant ureteral obstruction," "tandem ureteral stents," "metallic ureteral stents," "resonance stent," "metal mesh ureteral stents" and "extra-anatomic stents." The vast majority of studies were small and retrospective, with a large number of studies related to metallic stents. Given the heterogenous patient population and diversity of practice, it is difficult to truly assess the efficacy of each method. As there are no guidelines or major head-to-head prospective trials involving these techniques, it makes practicing up to the specific provider. However, this article attempts to provide a framework with which the urologist who is presented with malignant ureteral obstruction can plan in order to provide the individualized care on a case-by-case basis. What is clear is that prospective, randomized clinical trials are necessary to help bring evidence-based medicine and guidelines for patients with malignant ureteral obstruction.

A New Customized Ureteral Stent with Nonrefluxing Silicone End-piece to Alleviate Stent-related Symptoms in Malignant Diseases

OBJECTIVE

To evaluate the stent-related symptoms using a new customized ureteral stent with a nonrefluxing silicone end-piece.

METHODS

By decreasing the amount of material within the bladder, it should be possible to attenuate the stent-related symptoms. To minimize the amount of material, 17 consecutive patients already fitted with a double-pigtail stent for malignant ureteral obstruction agreed to be fitted with a customized stent where the bladder loop was replaced by a nonrefluxing silicone end-piece. The ureteral stent symptom questionnaire was prospectively administered to patients at baseline with double-pigtail stent and Day 15 after customized stent placement.

RESULTS

No difficulty in the placement of the customized stent was encountered. No stent failure, no dislodgment and no calcification were observed 6 months after stenting. The scores for the main domain "Urinary symptoms" (34.4 ± 3.6 vs 23.0 ± 7.0; P = .0004) and the question "Global quality of life" (4.4 ± 2.0 vs 2.4 ± 2.1; P = .01) were significantly decreased by the replacement of the double-pigtail stent by the customized stent.

CONCLUSION

The customized ureteral stent may constitute an improvement in the field of stent-related symptoms and seems fit for use in its current shape. Studies exploring and exploiting new concepts are greatly required to reduce stent-related symptoms in all patients including those with cancer.

Challenges To Attenuate Ureteric Stent-Related Symptoms: Reflections On The Need To Fashion A New Dynamic Stent Design Consequent Upon A Case Report

Double-pigtail stent has been widely used in urology for half a century now, but this device reduces the patient’s quality of life. Moreover, indwelling stent-related symptoms induce additional suffering to the pre-existing bladder disease. Novel concepts to prevent stent-related symptoms are greatly required. It has been suggested that changes in the size, form and stent positioning could ease discomfort. By decreasing the amount of material within the bladder, it should be possible to attenuate the stent-related symptoms. A customized stent has been developed to alleviate bladder symptoms. The major characteristic of this stent was in the replacement of the bladder part of the double-pigtail stent by a nonrefluxing silicone end-piece. Three months after stenting, the patient complained of sudden discomfort in the bladder area. On the X-ray, the end-pieces of the customized stents seemed to have slipped in the bladder. The customized stents were replaced by new ones after truncating and adjusting their lengths to the exact ureteric length and stent-related symptoms were then improved again. In the field of stent-related symptoms, stent mobility needs more attention than its intravesical position. The case hereby reported illustrates the variations of the symptoms which seem related to the stent mobility, the necessary shaping of the stent and, the possible research avenues for an innovative dynamic ureteric stent.