Ureteric stents, far from ideal

Modified endoluminal ureteral stenting for the management of proximal ureteral obstruction in two cats

Case series summary

Two cases of placement of modified endoluminal ureteral stents are described, for revision of a subcutaneous ureteral bypass (SUB) and for primary treatment of obstructive ureterolithiasis. Modified endoluminal stents were inserted through the ureterotomy, anchored in the renal pelvis with a single pigtail and shortened to a length sufficient to span the proximal ureter and ureterotomy site.

Relevance and novel information

The advantages of this approach as a surgical option for feline obstructive ureterolithiasis are demonstrated, including the avoidance of disruption, or bypass, of the ureterovesicular junction, minimisation of implanted foreign material and avoidance of intravesicular stent mass, maintenance of the physiological route of urine flow, including preservation of active distal ureteral function, and limitation of the potential complications of ureterotomy. The clinical efficacy of this adaptation of the previously published endoluminal stenting technique is demonstrated with its applicability de novo and in the revision of other stenting procedures.

Urethral beading: A unique radiographic finding following laser lithotripsy for ureteric stent encrustation

We present an interesting case of ureteric stent encrustation in a 35-year-old male who was lost to follow up for 8 months during the Covid-19 pandemic. After clearing severe stent encrustation with ureteroscopy and laser lithotripsy, the patient presented with urinary retention and multiple failed catheterizations. They were found to have numerous calcified urethral fragments secondary to stent encrustation, with a unique radiographic appearance of a string of beads overlying the pubic symphysis. A new stent was inserted and the patient was lost to follow up for a further 4 months, during which time pronounced encrustation formed again.

Preoperative estimate of natural ureteral length based on computed tomography and/or plain radiography

To predict natural ureter lengths based on clinical images. We reviewed our image database of patients who underwent multiphasic computed tomography urography from January 2019 to April 2020. Natural ureteral length (UL_CTU) was measured using a three-dimensional curved multiplanar reformation technique. Patient parameters including age, height, and height of the lumbar spine, the index of ureteral length using kidney/ureter/bladder (KUB) radiographs (C-P and C-PS) and computed tomography (UL_CT) were collected. UL_CTU correlated most strongly with UL_CT. R square and adjusted R square values from multivariate regression were 0.686 and 0.678 (left side) and 0.516 and 0.503 (right side), respectively. UL_CTU could be estimated by the regression model in three different scenarios as follows:

UL_CT + C-P

UL_CTUL = 0.405 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× UL_CTL\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$+$$\end{document}+ 0.626 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× C-P_L – 0.508 cm

UL_CTUR = 0.558 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× UL_CTR\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$+$$\end{document}+ 0.218 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× C-P_R + 6.533 cm

UL_CT

UL_CTUL = 0.876 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× UL_CTL\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$+$$\end{document}+ 6.337 cm

UL_CTUR = 0.710 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× UL_CTR\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$+$$\end{document}+ 9.625 cm

C-P

UL_CTUL = 0.678 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× C-P_L\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$+$$\end{document}+ 4.836 cm

UL_CTUR = 0.495 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× C-P_R\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$+$$\end{document}+ 10.353 cm

We provide equations to predict UL_CTU based on CT, KUB or CT plus KUB for different clinical scenarios. The formula based on CT plus KUB provided the most accurate estimation, while the others had lower validation values but could still meet clinical needs.

Magnetic double-J stent: Evaluation of tolerance and impact on quality of life compared to traditional double-J stent

INTRODUCTION

The placement of a ureteral stent is one of the most widely performed procedures in urology. It can have a negative impact on the patients' quality of life, requiring a cystoscopy for its removal. The objective of this study is to evaluate the symptoms and impact on quality of life derived from the use of a magnetic double-J stent (Black Star®) and compare them to those presented in patients with a traditional double-J stent (OptiMed®).

MATERIAL AND METHODS

We conducted a comparative, prospective, randomized study in 46 patients who underwent ureterorenoscopy with double-J stent placement between August 2019 and June 2020. Of all patients included, 23 had a traditional double-J stent placed (group A) and 23 had a magnetic double-J stent (group B) placed. We evaluated the results of the Ureteral Stent Symptom Questionnaire (USSQ) in both groups, assessed the technical difficulty related to stent removal and the pain during the procedure using the Visual Analogue Scale (VAS). We also reviewed the need for medical attention due to problems related to the stent or after its removal.

RESULTS

There were no statistically significant differences between groups regarding the answers in the USSQ and the complications related to the use of the stent. Group B showed less pain (1.52 vs. 4, VAS, p = 0.001) and less difficulty during removal (1.61 vs. 3, p < 0.001) associated with a shorter procedure duration (11.65 min vs. 22.17 min p < 0.001).

CONCLUSIONS

The tolerance shown by the use of magnetic double-J is comparable to the tolerance of traditional stent, since it does not cause an increase in urinary symptoms nor worsens the quality of life of patients during its use.

Magnetic double-J stent: evaluation of tolerance and impact on quality of life compared to traditional double-J stent

INTRODUCTION

The placement of a ureteral stent is one of the most widely performed procedures in urology. It can have a negative impact on the patients' quality of life, requiring a cystoscopy for its removal. The objective of this study is to evaluate the symptoms and impact on quality of life derived from the use of a magnetic double-J stent (Black Star ®) and compare them to those presented in patients with a traditional double-J stent (OptiMed®).

MATERIAL AND METHODS

We conducted a comparative, prospective, randomized study in 46 patients who underwent ureterorenoscopy with double-J stent placement between August 2019 and June 2020. Of all patients included, 23 had a traditional double-J stent placed (group A) and 23 had a magnetic double-J stent (group B) placed. We evaluated the results of the Ureteral Stent Symptom Questionnaire (USSQ) in both groups, assessed the technical difficulty related to stent removal and the pain during the procedure using the Visual Analogue Scale (VAS). We also reviewed the need for medical attention due to problems related to the stent or after its removal.

RESULTS

There were no statistically significant differences between groups regarding the answers in the USSQ and the complications related to the use of the stent. Group B showed less pain (1,52 vs. 4, VAS, p = 0.001) and less difficulty during removal (1,61 vs. 3, p < 0,001) associated with a shorter procedure duration (11,65 min vs. 22,17 min p < 0,001).

CONCLUSIONS

The tolerance shown by the use of magnetic double-J is comparable to the tolerance of traditional stent, since it does not cause an increase in urinary symptoms nor worsens the quality of life of patients during its use.

Ureteric stents: Overview of current clinical applications and economic implications

Ureteric stents are one of the most crucial tools used for various clinical conditions in the urological field. Placement of a ureteric stent, for short- or long-term use, remains one of the commonest urological interventional procedures. In the past few decades, ureteral stents have undergone notable technological advancements. However, an ideal stent without significant side-effects is yet to be engineered. Indwelling ureteric stents are often accompanied by physical distress to the patient and clinical complications, such as bacterial adhesion, encrustation, malpositioning, stent fracture and forgotten stent syndrome, that influence patients' health-related quality of life. In the market, different stent types are available, designed to reduce infections, and improve patient symptoms and tolerance. In this review, we have emphasized the recent developments that have taken place in stent design, size, materials and coating. This overview looks at current practices and problems related to stents, along with clinical and economic considerations. Few trial studies have been enumerated in the context of utilization of a ureteral stent symptom questionnaire and various stent models to compare their effects in patients.

How bothersome double-J ureteral stents are after semirigid and flexible ureteroscopy: a prospective single-institution observational study

PURPOSE

To evaluate in details the actual extent of double-J stent-related symptoms after semirigid (URS) and flexible (RIRS) ureteroscopy using a validated questionnaire.

METHODS

We asked to complete the Ureteric Stent Symptoms Questionnaire (USSQ) to all stone patients undergoing URS or RIRS with stent placement from 2010 to 2015. Stent-related symptoms' prevalence, severity, and impact on daily life were analyzed using descriptive statistics and five-order Likert scales. Subgroups analyses were performed.

RESULTS

232 patients completed the USSQ. Stents had a deep impact on urinary symptoms (daily frequency ≥ 1 per hour 59.1%, ≥ 1 nocturnal micturition 90.1%, urgency 86.6%, burning 82.3%) that represented a problem for 88.4% of patients. 83.2% complained of pain, mostly in the kidney (67.9%) or in the bladder area (31.3%), particularly during physical activity (72.9%) and micturition (77.0%). Pain interfered with everyday life in 92.2%. General health, working, and sexual activity were also affected. 62.0% of patients would be dissatisfied (51.6% unhappy or terrible) if further ureteral stenting was proposed in future. Younger patients and females were more affected. Limitations include observational design and lack of baseline evaluation.

CONCLUSIONS

Ureteral stents are responsible for significant urinary symptoms and pain after semirigid and flexible ureteroscopy. They also considerably affect general health, working and sexual activity. Urologists should consider it carefully before stenting, inform patients about stent-related symptoms, and minimize stent indwelling time.

Office-based ureteric stent removal is achievable, improves clinical flexibility and quality of care, whilst also keeping surgeons close to their patients

Introduction

Diagnostic pressure on endoscopy suites can result in stent removal not receiving the required priority and unnecessary morbidity for patients. As well as using stents with extraction strings, the introduction of a portable single-use flexible cystoscope for ureteric stent removal (Isiris™), offered an opportunity to negotiate these issues by relocating stent removal to the office/clinic. This study aimed to determine whether such flexibility reduced stent dwell time with the assumption this would improve patient experience and decrease associated complications.

Materials and methods

A retrospective review of ureteric stents placed during stone procedures was undertaken. Data collection included; patient demographics; stent dwell times; the number of emergency department (ED) attendances and hospital readmissions; procedure cancellation rates and the number of urinary tract infections.

Results

In total, 162 stents were removed (113 Standard, 34 Isiris™, 15 via strings). Excess dwell time was reduced in both Isiris™ (median 1 day, mean 1.37 days, p = 0.0009) and Strings Groups (median 0.96 days, mean 0.96 days, p = 0.022) compared with the Standard Group (median 8 days, mean 15.34 days).

ED attendances and readmissions were reduced by 33.5% and 22% respectively in the Isiris™ Group compared with the Standard Group. There were no ED attendances in the Strings Group. Reductions in length of stay, urine infections and cancellation on the day of procedures were also observed.

Conclusions

The clinical flexibility provided by Isiris™ and 'stents on strings' has objectively improved patient experience and is associated with a reduction in complications as well as increasing diagnostic capacity and cost efficacy.

Pilot Study to Determine Optimal Stent Duration Following Ureteroscopy: Three versus Seven days

Background/Aims

Many providers elect to place a stent following ureteroscopy for nephrolithiasis, but little data exists on the optimal duration to leave a stent. We sought to determine whether there are any differences in post-operative outcomes for patients with a 3 versus 7-day stent following ureteroscopy.

Methods

We retrospectively reviewed 247 patients who underwent unilateral ureteroscopy with lithotripsy, 79 of whom removed a stent with an extraction string at 3 or 7 days post-operatively. These 2 groups were compared with regard to demographic information, pre-operative variables, and post-operative outcomes.

Results

Of all patients, 33% experienced a post-procedure related event (phone call, extra clinic visit, and emergency department visit) within 30 days of their procedure, 39% of 3-day stent patients compared to 21% of 7-day patients (p = 0.11). Within the 3 days following stent removal, 3-day stent patients were significantly more likely to have a post-procedure related event than 7-day patients (23 vs. 3%, p = 0.026).

Conclusion

One third of patients with a post-operative ureteral stent will seek medical care in the 30 days following ureteroscopy. Leaving a stent for 3 versus 7 days may lead to worse outcomes with regard to post-operative events and fank pain.

Ureteric stents: The past, present and future

Ureteric stents are fundamental to modern-day urological practice. This article aims to chronicle their development over the last century and the key individuals whose efforts have made their development possible. Early stents were ureteric catheters that were exteriorised outside the body and were associated with complications including migration, infection and encrustation.

The use of polyethylene stents in humans was first reported by Tulloch in 1952. Polyethylene was thought to be a promising material due to its durability and water-repellent nature. It would, however, suffer the problems that would become associated with stents over the following decades mentioned above.

The first silicone ureteric stents were developed in the 1960s by Zimskind and provided prolonged, efficient drainage but were complicated with stent migration. Collars, wings, flanges and barbs were developed to help prevent migration. Finney developed a double ‘pig-tail’ stent in the 1970s which helped to prevent both proximal and distal migration and the modern-day ureteric stent was born.

Modern polymers have been developed such as polyurethane or styrene ethylene-butylene (C-flex®). Metal stents have also been used over the last three decades including the Wallstent™, Resonance® and Memokath™ stents. They have shown promising results particularly when long-term relief of ureteric obstruction is needed.

Various strategies are available for removal including cystoscopically, stents with a metallic end that can be removed by using a catheter with a magnet at the proximal end, tethered stents that can be removed noninvasively either by the urologist, nurse or even by the patient and dissolvable stents which are in development.

Primary and Secondary Percutaneous Ureteral Stent Placement: Comparison of Stent Patency and Clinical Outcome

OBJECTIVES

To compare early double J ureteral stent (DJUS) dysfunction rate and long-term patency between two percutaneous ureteral stent placement methods: single-stage (primary) or two-stage (secondary) procedures.

METHODS

A total of 250 (176 primary and 74 secondary) DJUS placements performed on interventional unit were retrospectively reviewed between February 2008 and March 2014. Early DJUS dysfunction was defined as no passage of contrast media into the urinary bladder in 2-3 days after placement. Long-term patency was considered if the ureteral stent functioned for 3 months (time point for a first routine DJUS change). Amount of blood retained in the collecting system was scored on nephrostogram immediately after DJUS placement with three levels of score.

RESULTS

The overall early DJUS dysfunction rate and long-term patency rate were 30.8 and 96.7%. The early DJUS dysfunction rates were similar in primary and secondary DJUS placements (30.7 and 31.1%, P = 0.950). The long-term patency rates were similar in primary and secondary groups (96.2 and 97.9%, P = 0.928). The amount of blood retained in the collecting system between primary and secondary groups was not significantly different. The early DJUS dysfunction rate significantly increased with increasing blood retention.

CONCLUSIONS

The early DJUS dysfunction rates and long-term patency are similar in primary and secondary DJUS placement. However, the early DJUS dysfunction rate can be increased by increasing the blood retention in the collecting system.

Immersed multilayer biodegradable ureteral stent with reformed biodegradation: An in vitro experiment

Objective

The aim of this study was to develop a novel immersed multilayer biodegradable ureteral stent with reformed biodegradation and evaluate it in vitro.

Methods

Poly(glycolic-co-lactic acid) (PGLA), microsphere zein and BaSO4 were employed to produce a multilayer biodegradable stent using immersion technology. Tests of the biodegradable stents and conventional control stents were conducted in human urine in vitro to evaluate the biodegradable properties. The biocompatibility was assessed by the morphology and proliferation of urine-derived cells cultured with extracted media from the biodegradable stent and a latex material positive control.

Results

An immersed multilayer biodegradable stent was successfully produced. It began to degrade in week 2 and was fully degraded by week 4. The mass loss ratio in the first 2 weeks was low (approximately 10.0% at 1 week, 20.0% at 2 weeks) and increased after 3 weeks (approximately 70%) to the end of testing. During the first 2 weeks, the radial compression load performances of the biodegradable stents were better than those of the control stents with statistically significant differences ( p = 0.00, p = 0.01) and the tensile strengths were lower in the biodegradable stents than those in the control stents throughout the experiment. SEM showed that the stents degraded layer by layer from the outer to the inner wall. The influences on the cells of extracted medium from the biodegradable stents were morphologically slight and lower than 10% in relative growth rates.

Conclusions

This preliminary study demonstrates that the immersed multilayer biodegradable ureteral stent has good radial compression and biocompatible performance and can be degraded in vitro within 4 weeks in a moderate manner.

Use of Self-Expanding Metallic Ureteral Stents in the Secondary Treatment of Ureteral Stenosis Following Kidney Transplantation

INTRODUCTION

To evaluate the safety and efficacy of self-expanding metal stents in the treatment of ureteral stenosis following kidney transplantation.

MATERIALS AND METHODS

Seven patients who developed benign stenosis after kidney transplantation were treated by a self-expanding metallic stent implantation from June 2007 to March 2014. All patients had undergone at least one open surgical procedure and one endourologic procedure for treatment of the stenosis. The extent of stenosis varied from 1.2 to 3.7 cm. Ultrasonography, urography, diuretic renography, and urine culture were performed every 3 months after stent insertion. Ureteroscopic examination was performed when needed.

RESULTS

Stent placement was technically effective in all cases. The mean operative time was 37 minutes (range, 26-59 minutes). Lower urinary-tract symptoms and the ipsilateral flank pain were common early-stage complications and were greatly relieved after an average of 3 months. The mean follow-up duration was 38 months (range, 13-86 months), and no stent migration or fragmentation was observed. Urothelial hyperplasia occurred in only one patient and was effectively managed with a Double-J stent. Five patients had normal stable renal function; the remaining two had impaired renal function, including one patient with a preoperative renal failure who required dialysis at the end of the follow-up period (36 months).

CONCLUSIONS

As an alternative to open surgery, implantation of a self-expanding metal stent is a safe and effective treatment for ureteral stenosis in patients who have undergone kidney transplantation.

Do ureteric stent extraction strings affect stent-related quality of life or complications after ureteroscopy for urolithiasis: a prospective randomised control trial

OBJECTIVE

To determine whether ureteric stent extraction strings affect stent-related quality of life (QoL) or increase complications after ureteroscopy (URS) for stone disease.

PATIENTS AND METHODS

In all, 68 patients undergoing URS (October 2011 to May 2013) for stone disease were randomised to receive a ureteric stent with or without an extraction string. Patients completed the Ureteric Stent Symptom Questionnaire (USSQ) on postoperative days 1 and 6, and 6 weeks after stent removal. Pain was assessed at stent removal. Adverse events, including early stent removal, stent migration, retained stent, urinary tract infection (UTI), emergency room (ER) visits and postoperative phone calls were monitored.

RESULTS

There was no difference in stent-related QoL as measured by the USSQ between those with and without a stent extraction string, pain at stent removal between those who pulled their stent independently vs those who underwent cystoscopy for stent removal, or in the rate of UTIs, ER visits or phone calls between groups. Five patients (four female, one male) removed their stent early by inadvertently pulling the string; none required replacement. Patients without a string had a significantly longer period with the postoperative ureteric stent (10.6 vs 6.3 days, P < 0.001). One patient without a stent string retained her ureteric stent for 6 months, which was removed by cystoscopy without incident.

CONCLUSION

Ureteric stent extraction strings may offer several advantages without increasing stent-related urinary symptoms, complications, or postoperative morbidity.

Role of α-blockers in the treatment of stent-related symptoms: a prospective randomized control study

OBJECTIVE

To properly use the Ureteric Symptom Score Questionnaire (USSQ) to evaluate, in a randomized control study, the effect of 2 different α-blockers in improving symptoms and quality of life in patients with indwelling ureteral stents.

METHODS

After institutional review board approval, 150 consecutive patients with a double-J ureteral stent inserted after extracorporeal shockwave lithotripsy (ESWL) or ureteroscopic stone treatment were randomly assigned to receive tamsulosin 0.4 mg, alfuzosin 10 mg, or placebo. The validated USSQ was completed 1 and 4 weeks after stent insertion and 4 weeks after stent removal. The Kruskal-Wallis test for independent samples for non-normally distributed ordinal variables, chi-square to compare proportions or differences, and 1-way analysis of variance (ANOVA) for independent samples to compare for differences in case of continuous variables were used for statistical analysis of the results.

RESULTS

Patients receiving α-blockers expressed an overall statistically significant lower urinary (P <.001), pain (P <.001 with stent in situ), and general health index (P <.002) scores. Sexual life and quality of life were also positively influenced. Quality of work was not influenced. No patients had to discontinue medication because of side effects or underwent stent removal before the due date. There was no difference in various outcomes between the 2 α-blockers.

CONCLUSION

Stent-related morbidity is a reality in the majority of patients. Simple medication, such as α-blockers, reduce stent-related symptoms and the negative impact on quality of life. It seems that stent-related symptom improvement is independent to the type of α-blocker.

Braided thin-walled biodegradable ureteral stent: preliminary evaluation in a canine model

OBJECTIVES

To evaluate a novel designed degradable ureteral stent.

METHODS

A total of 24 male Beagles, each with bilateral stents implanted (a biodegradable ureteral 4.5-Fr stent and a standard 4-Fr biostable stent) were divided into four groups. Intravenous pyelography, B-mode ultrasonography, and blood and urine tests were carried out before the procedure (0 weeks), and at 1-, 2-, 3- and 4-week intervals. Meanwhile, the mechanical characteristics of stents were tested, and scanning electron microscopy images of the biodegradable braided stents were obtained at different time-points postoperatively. In addition, histopathological changes were compared between the two different stents.

RESULTS

All biodegradable braided stents began degrading at 1 week, and had completely degraded by 4 weeks. Hydronephrosis was equivalent during the first 2 weeks, but less with the biodegradable stents than with the control biostable stents at 3 and 4 weeks. Preoperative and postoperative blood and urine results were similar. The mechanical properties of the biodegradable stents were better than conventional biostable stents. Scanning electron microscopy images obtained at different weekly intervals showed that stents degraded in a predictable fashion. Histological testing of the urinary tract showed that the stent-related tissue reactivity of the two different stents were similar.

CONCLUSIONS

Our novel braided thin-walled biodegradable stents provide temporary renal drainage as good as commercially available biostable stents. They also have good biocompatibility and physical characteristics. Therefore, they might have clinical application.

The double wire technique: an alternative method for difficult ureteroscopic access

We read with great interest the study report by Ji et al. (Urol Res, doi: 10.1007/s00240-012-0476-0 , 2012) about the impact of the intentional ureteral stenting on the success rate of calculus extraction by second ureteroscopy, when the initial ureteroscopy failed. Actually, sometimes ureteral stone treatment pose challenging problems for the urologists. This study has filled an important gap on this field. If flexible ureteroscopy and laser lithotripter are not available pre-existing stent may improve the success rate of a subsequent ureteroscopy for impacted ureteral stones. Because, post-stent ureteroscopy has the advantage of working through a dilated ureter. We would like to add some additional comments and suggestions in addition to the authors' discussion, which is noteworthy in several respects.

Predictors of morbidity in patients with indwelling ureteric stents: results of a prospective study using the validated Ureteric Stent Symptoms Questionnaire

OBJECTIVE

To assess the predictors of morbidity in patients with indwelling ureteric stents using a validated questionnaire.

PATIENTS AND METHODS

Eighty-six consecutive patients with indwelling double-J ureteric stent of different length and size enrolled at an Italian tertiary academic centre were prospectively evaluated with the Italian-validated Ureteric Stent Symptoms Questionnaire (USSQ), which explores the stent-related symptoms in six domains. Ureteric stents were placed for benign ureteric obstruction or after uncomplicated ureterorenoscopy, and were all removed after 28 days. The questionnaire was administered on days 7 and 28 after stent placement and on day 28 after removal. A plain abdominal X-ray was performed on days 7 and 28 after placement to determine stent location. Univariable and multivariable analyses tested the association of patient age, sex and body mass index (BMI), and stent side, length, calibre and distal loop location, with the index score of the various domains on days 7 and 28.

RESULTS

All patients completed the study. At multivariable analysis, on day 7, sex, BMI and stent calibre were significantly associated with one domain (general health, body pain and work performance, respectively), while location of stent distal loop was significantly associated with five domains (urinary symptoms, body pain, general health, work performanc, and sexual matters). On day 28, body mass index was significantly associated with two domains (body pain and general health), while location of stent distal loop remained significantly associated with the same five domains (urinary symptoms, body pain, general health, work performance and sexual matters).

CONCLUSION

Location of stent distal loop with respect to midline had the strongest association with most domains of the USSQ on both days 7 and 28 after stent placement. The visualization of stent distal loop crossing the midline may therefore identify patients at higher risk of post-procedural morbidity requiring early management.

Ureteric stent card register - a 5-year retrospective analysis

INTRODUCTION

Ureteric stenting is a common urological procedure. Forgotten stents have a well-documented morbidity and mortality. Therefore, we asked the question, is a stent register an important factor in reducing the number of lost or overdue stents?

PATIENTS AND METHODS

We conducted a retrospective review of 203 patients who had ureteric stents inserted in the operating theatre, for the 5-year period 1 December 1998 to 1 December 2003. We analysed all stent cards, patient notes and theatre logs; where no record of stent removal was found, we contacted the patient, their GP or their local hospital.

RESULTS

A total of 191 patients were identified from the stent card register. An additional 12 patients were found from the theatre logs, but with no record in the stent card register. Of the 203 patients, 8 had bilateral stents. The most common indication for stenting was stone disease. Of the 203 patients, 11 had overdue stents and 51 had no record of the stents ever being removed. The 51 presumed 'forgotten' stents were traced, and it was found that 42 patients had had their stents removed by other hospitals, and 9 patients died with stents in situ, but before they were due for removal.

CONCLUSIONS

Our current stent card tracking system is ineffective, because it was infrequently reviewed. However, despite overdue and 'forgotten' stents which were removed by other hospitals, no patients came to any real harm and we had no lost stents. Our stent register system did not appear to play any role in terms of preventing stent loss, and it seems likely that there are other more effective safeguards in place to prevent this from happening. However, if a stent register was required at all, a computerised system would be preferable. Alternatively, patients could share some of the responsibility of stent tracking with their clinicians.

[Coating with plasma-deposited functionalized diamond-like carbon to decrease encrustations on urological implants]

The double-J stents used today for palliative artificial urinary diversion very often show extreme formation of encrustations, even a short time after implantation. Despite increased scientific material development, the complication rate has not really been strongly influenced. Grant-aided by the German Federal Ministry of Education and Research, we chose a new interdisciplinary and translational approach by coating standard stent materials with plasma-deposited amorphous diamond-like carbon. These stents show clearly reduced rates of encrustation in vitro. Ongoing clinical trials demonstrate a further enhancement of this effect in vivo. The underlying mechanisms are being investigated by extending the established in vitro model, thereby pushing research in this field to a new level.

Diamond-Like Carbon Coatings on Ureteral Stents—A New Strategy for Decreasing the Formation of Crystalline Bacterial Biofilms?

PURPOSE

Any catheter material placed in the urinary tract provides a surface for bacterial colonization and, therefore, it is susceptible to encrustation with crystalline bacterial biofilm. Encrustation and blockage by biofilms remain a major complication in patient care. Most patients with indwelling ureteral stents experience irritative symptoms related to these implants and many experience discomfort.

MATERIALS AND METHODS

Plasma deposited diamond-like amorphous carbon coatings are well-known for their excellent biocompatibility. A low temperature, low pressure plasma enhanced chemical vapor deposition technology was developed especially for coating polymeric medical implants with diamond-like carbon. We investigated the ability of diamond-like carbon to decrease the formation of crystalline bacterial biofilm as well as stent related side effects and discomfort. Diamond-like carbon coated ureteral Double-J stents were tested in vivo.

RESULTS

In 10 patients with heavy encrustation, different underlying diseases and a stent removal frequency of less than 6 weeks due to encrustation a total of 26 diamond-like carbon coated stents were successfully tested for their ability to decrease the extent of crystalline biofilm formation. There was a 2,467-day period of experience with diamond-like carbon coated stents. No primarily stent related complications occurred. No crystalline biofilm formation was observed in vivo. Excellent and facile handling, a less painful replacement procedure and high tolerance of application were reported by physicians and patients. Due to low friction the coated stents could be placed and removed much more easily than standard stents. The frequency and severity of symptomatic urinary tract infections were distinctly decreased.

CONCLUSIONS

Diamond-like carbon coating is a new strategy to improve the surface properties of ureteral stents. This novel surface effectively decreases friction, encrustation tendencies and biofilm formation.

Ureteral stent placement without postprocedural nephrostomy tube: experience in 41 patients

PURPOSE

To evaluate one-stage antegrade ureteral stent placement without postprocedural nephrostomy tube.

MATERIALS AND METHODS

Tubeless ureteral stent insertion was attempted in 41 (30 men, 11 women; eight, benign obstruction; nine outpatients) of 97 adults (56 excluded). Patients were clinically stable with known ureteral obstruction and had been referred for antegrade ureteral stent insertion. Exclusion criteria were infection, coagulopathy, or emergency cases. After renal access was achieved, ureteral stents were inserted. If drainage was satisfactory and there was no marked procedural bleeding, all access was removed without leaving a nephrostomy tube behind. Technical and clinical success rates and complications were assessed with review of radiologic and clinical notes. If one-stage stent insertion was unsuccessful, a nephrostomy tube was inserted and two-stage stent placement was performed. All 56 patients excluded from this study underwent two-stage stent placement. Major complication rate was assessed (Fisher test).

RESULTS

One-stage stent insertion was technically successful in 36 (88%) patients; two with an identifiable risk factor (recent bladder operation, retrograde ureteral instrumentation) developed septicemia that required repeat nephrostomy tube insertion and 2-8 extra days of hospitalization. Clinical success rate was 83% (34 of 41). No major bleeding occurred. In 13 (36%) of 36 patients, hematuria lasted longer than 24 hours but resolved without further intervention or blood transfusion. In those who underwent two-stage stent placement (n = 61), technical success rate was 100%, but clinical success rate was 98%; one patient developed septicemia, and no major hemorrhage occurred. Difference in major complication rate between groups was not significant (6% [two of 36] vs 2% [one of 61]; P =.55).

CONCLUSION

One-stage tubeless antegrade ureteral stent insertion in selected cases showed 88% technical success rate and 83% clinical success rate, with no major hemorrhage.

Indwelling ureteral stents: evaluation of symptoms, quality of life and utility

PURPOSE

We report the prevalence of symptoms associated with ureteral stents, their impact on health related quality of life and utility analysis based on the validation studies of the new ureteral stent symptom questionnaire (USSQ).

MATERIALS AND METHODS

A total of 85 consecutive adult patients with unilateral indwelling ureteral stents who were asked to participate during the validation phases of the USSQ were considered for this analysis. They were asked to complete the USSQ and the EuroQol, a weighted utility instrument, 4 weeks after stent insertion and removal. In addition, 40 patients were asked to complete these questionnaires 1 week after stent insertion to assess the prevalence of symptoms and utility values at different times.

RESULTS

Of the 85 patients 62 (73%) with a mean age of 50 years completed the necessary questionnaires. Urinary symptoms and pain that affected work performance and general health were important stent related problems. Of the patients 78% reported bothersome urinary symptoms that included storage symptoms, incontinence and hematuria. More than 80% of patients experienced stent related pain affecting daily activities, 32% reported sexual dysfunction, and 58% reported reduced work capacity and negative economic impact. The mean EuroQol utility values, which indicate patient satisfaction with treatment, were significantly reduced following stent insertion.

CONCLUSION

Urinary symptoms and pain associated with indwelling ureteral stents interfere with daily activities and result in reduced quality of life in up to 80% of patients. Stents are associated with negative functional capacity and reduced utility values. The results have implications in terms of routine clinical practice, patient counseling and future stent research.

The development and validation of a patient-information booklet on ureteric stents

OBJECTIVE

To report a scientific approach incorporating patient preferences towards the development of a patient-information booklet about ureteric stents.

PATIENTS AND METHODS

Phase 1 of the study included 35 adult patients with ureteric stents who were surveyed using semi-structured interviews (four patients) and a questionnaire (31 patients) to assess various issues relating to information given to patients about ureteric stents. In addition, published papers were assessed and clinicians' opinions sought. The results formed the basis for a comprehensive patient-information booklet about ureteric stents that incorporated patients' views and preferences. In phase 2, the booklet was tested and formally validated by inviting 30 patients, a panel of 20 urologists and general practitioners, and five stent manufacturers to assess the booklet for adequacy, coverage and readability of the content.

RESULTS

Of the 35 patients, 30 (19 men and 11 women, mean age 49 years, range 20-78) participated in the initial survey; 80% of patients reported dissatisfaction about the information they received. Patients wanted more information about the use, adverse events and effects of stents on daily life; 85% preferred all relevant information about the stents to be in a written format with illustrative drawings. An eight-page booklet was thus developed. The validation study revealed that the booklet matched patients' experiences (approval score of 9/10, range 8-10) and was reported as satisfactory by clinicians and manufacturers.

CONCLUSIONS

A validated information booklet on ureteric stents was developed, incorporating patients' expectations and views. This booklet is expected to be an effective tool for patient communication that would help patients cope better with indwelling stents and be useful in counselling patients. A similar approach could be adopted for the development of other patient-information packs.