Second Prize: Double-Blind Randomized Controlled Trial Assessing the Safety and Efficacy of Intravesical Agents for Ureteral Stent Symptoms after Extracorporeal Shockwave Lithotripsy

Open Label, Pilot Evaluation of the Safety and Efficacy of Intravesical Sustained Release System of Lidocaine and Oxybutynin (TRG-100) for Patients With Interstitial Cystitis/Bladder Pain Syndrome, Overactive Bladder and Patients With Retained Ureteral Stents Following Endourological Interventions

BACKGROUND

Intravesical instillation of analgesic and anticholinergic drugs have shown efficacy in the treatment of pain and voiding symptoms. Unfortunately, drug loss with urination and dilution in the bladder limit their durability and clinical usefulness. We have recently developed and tested in vitro, a sustained delivery system (TRG-100) of fixed-dose combination of lidocaine and oxybutynin designed to allow for a longer exposure of the urinary bladder to the drugs.

OBJECTIVE

To asses the safety and efficacy of TRG-100 in Interstitial Cystitis/Bladder Pain Syndrome (IC/BPS), overactive bladder (OAB), and endourological intervention stented (EUI) patients in an open-label, prospective study.

METHODS

Thirty-six patients were enrolled: 10 IC/BPS, 10 OAB, and 16 EUI. EUI patients received a once-weekly installation until stent removal, OAB and IC/BPS patient received weekly installations for 4 consecutive weeks. Treatment effect was assessed by visual analog scale (VAS) score for the EUI group, voiding diaries for OAB group and VAS score, voiding diaries and O'Leary Sant Questionnaires for the IC/BPS group.

RESULTS

The EUI group showed a mean 4-point improvement in their VAS score. The OAB group showed 33.54% reduction in frequency of urination and IC/PBS group showed a mean of 3.2-point improvement in their VAS score, 25.43% reduction in frequency of urination, and a mean 8.1-point reduction in O'Leary Sant Questionnaires score. All changes were statistically significant.

CONCLUSION

Intravesical instillation of TRG-100 was found to be safe and efficient in reducing pain and irritative bladder symptoms in our study population. TRG-100 efficacy and safety should be further assessed in a large, randomized control trial.

Freeze-casting porous chitosan ureteral stents for improved drainage

As a new strategy for improved urinary drainage, in parallel to the potential for additional functions such as drug release and self-removal, highly porous chitosan stents are manufactured by radial, bi-directional freeze-casting. Inserting the porous stent in to a silicone tube to emulate its placement in the ureter shows that it is shape conforming and remains safely positioned in place, also during flow tests, including those performed in a peristaltic pump. Cyclic compression tests on fully-hydrated porous stents reveal high stent resilience and close to full elastic recovery upon unloading. The drainage performance of the chitosan stent is evaluated, using effective viscosity in addition to volumetric flow and flux; the porous stent's performance is compared to that of the straight portion of a commercial 8 Fr double-J stent which possesses, in its otherwise solid tube wall, regularly spaced holes along its length. Both the porous and the 8 Fr stent show higher effective viscosities, when tested in the silicone tube. The performance of the porous stent improves considerably more (47.5%) than that of the 8 Fr stent (30.6%) upon removal from the tube, illustrating the effectiveness of the radially aligned porosity for drainage. We conclude that the newly-developed porous chitosan ureteral stent merits further in vitro and in vivo assessment of its promise as an alternative and complement to currently available medical devices. STATEMENT OF SIGNIFICANCE: No papers, to date, report on porous ureteral stents, which we propose as a new strategy for improved urinary drainage. The highly porous chitosan stents of our study are manufactured by radial, bi-directional freeze casting. Cyclic compression tests on fully-hydrated porous stents revealed high stent resilience and close to full recovery upon unloading. The drainage performance of the chitosan is evaluated, using effective viscosity in addition to volumetric flow and flux, and compared to that of the straight portion of a commercial 8 Fr double-J stent. The performance of the porous stent improves considerably more (47.5%) than that of the 8 Fr stent (30.6%) upon removal from the tube, illustrating the effectiveness of the radially aligned porosity for drainage. While further studies are required to explore other potential benefits of the porous stent design such as antimicrobial behavior, drug release, and biodegradability, we conclude that the newly-developed porous chitosan ureteral stent has considerable potential as a medical device.

Ureteral stents in urolithiasis

Ever since the ureteral stent design was fitted with a curl on both sides to prevent it from migrating up or down the ureter some 40 years ago, its use has gained tremendous momentum, aiding in the rise and evolution of endourology and has confidently kept its place in modern time urology. Over the past four decades, several designs, coating and biomaterials have been developed, trying to reduce infection, encrustation and other stent related symptoms. As the ideal stent has not yet been discovered, different ways of helping patients with their complaints have been researched. This review will cover these aspects of stent use in urolithiasis.

Comparison of safety and efficacy of silodosin, solifenacin, tadalafil and their combinations in the treatment of double-J stent- related lower urinary system symptoms: A prospective randomized trial

OBJECTIVE

To evaluate the efficacy and safety of silodosin, solifenacin, tadalafil and their combinations in reducing double J (DJ) stent-related symptoms (SRS).

MATERIAL AND METHODS

A total of 335 patients who underwent DJ stenting and develop SRS at 1^st week were randomized into eight groups. Ureteral stent symptom questionnaire (USSQ) and Quality of life (QOL) scores were noted in each group: Group A-Silodosin (8 mg OD)+ Solifenacin (10 mg OD)+ Tadalafil (5 mg OD), B - Silodosin 8 mg OD, C - Solifenacin 10 mg OD, D- Tadalafil 5 mg OD, E- Silodosin (8 mg OD) + Solifenacin (10 mg OD), F- Silodosin (8 mg 0D)+ Tadalafil (5 mg OD), G- Solifenacin (10 mg OD)+ Tadalafil (5 mg OD) and H-placebo. Analgesic (diclofenac 50 mg) was given as per requirement. All groups received the drugs for 14 days and again USSQ, QOL score with analgesic requirement were noted in each group.

RESULTS

USSQ score was similar in all groups at 1^st week but all groups (Groups A-G) led to significant decrease in USSQ score at 3^rd week as compared to Group H with less requirement of analgesic. However when we compared groups with each other we found that mean USSQ score and analgesic requirement was favoring Group E as compared to other groups. Quality of life score was also best in Group E (mean 1.5) (p<0.05).

CONCLUSION

Combination therapy with silodosin and solifenacin (group E) was effective for relieving SRS with improved quality of life and less requirement of analgesic than any other groups and should be considered in patients who develop SRS.

Novel in-situ gel for intravesical administration of ketorolac

The urinary bladder stores urine until the time of urination. Systemic administration of drugs to treat bladder diseases faces several limitations. Therefore, intravesical drug delivery is a promising alternative route of administration. An in-situ gel is used to form a gel inside the bladder cavity and ensure continuous release of the drug even after urination. The objective of the present study was to optimize an in-situ gel formulation of poloxamer and chitosan for intravesical delivery of ketorolac tromethamine. The gelling temperature of the prepared combinations ranged from 20.67 to 25.8 °C. In-vitro release of KT was sustained for up to 7 h using a poloxamer concentration ranging from 17% to 19% and a chitosan concentration ranging from 1% to 2%. Design-Expert® 10 was used to select the optimized formulation (poloxamer/chitosan 17/1.589% w/w) which significantly (p < 0.05) extended the drug release more than each polymer alone. An ex-vivo study showed the ability of the optimized formulation to sustain drug release after emptying two times to mimic urination. Furthermore, the formed gel adhered to the bladder tissue throughout the time period of the experiment. Intravesical administration of the optimized formulation to rabbits via catheter showed no obstruction of urine flow and continuous release of the drug for 12 h.

Intraureteral lidocaine for ureteral stent symptoms post-ureteroscopy: A randomized, phase 2, placebo-controlled trial

INTRODUCTION

Ureteral stent and ureteral manipulation-related pain is a significant complication for patients undergoing ureteroscopy. Herein, we report a phase 2, randomized trial to assess efficacy of direct instillation of intraureteral lidocaine in reducing postoperative pain and ureteral stent symptoms.

METHODS

We performed a randomized, double-blinded trial of patients undergoing elective ureteroscopy for ureteral calculi. Patients were randomized to direct instillation of 2% lidocaine plus bicarbonate, or to normal saline as control. The primary outcome of interest was early postoperative pain scores. Patients completed10-point visual analog pain scale at one-hour, two-hour, four-hour, 24-hours, four- and seven-day time points. Other outcome measurements collected included a medication diary and voiding questionnaire.

RESULTS

A total of 41 patients were randomized in the study. Mean flank pain scores at one hour were 2.2 (±2.9) vs.1.9 (±2.4) in the intervention and placebo group, respectively (p=0.84). There was no significant difference at any time point between the intervention and placebo groups in patient-reported pain scores. Patients reported lower dysuria scores at all time points in the lidocaine group, however, none reached statistical significance. There was no difference in complication rates or adverse effects between groups.

CONCLUSIONS

In this randomized, phase 2 study, direct instillation of lidocaine into the ureter did not appear to significantly improve pain or voiding symptoms following stented ureteroscopy.

Ureteral stent technology: Drug-eluting stents and stent coatings

Ureteral stents are commonly used following urological procedures to maintain ureteral patency. However, alongside the benefits of the device, indwelling stents frequently cause significant patient discomfort (pain, urgency, frequency) and can become encrusted and infected. The importance of these sequelae is that they are not only bothersome to the patient but can lead to significant morbidity, urinary retention, ureteral damage, recurrent infections, pyelonephritis and sepsis. When these problems occur, stent removal or replacement alongside antibiotic, analgesic and/or other symptom-modifying therapies are essential to successfully treat the patient. In an attempt to prevent such morbidity, numerous approaches have been investigated over the past several decades to modify the stent itself, thereby affecting changes locally within the urinary tract without significant systemic therapy. These strategies include changes to device design, polymeric composition, drug-elution and surface coatings. Of these, drug-elution and surface coatings are the most studied and display the most promise for advancing ureteral stent use and efficacy. This article reviews these two strategies in detail to determine their clinical potential and guide future research in the area.

New developments in ureteral stent design, materials and coatings

Ureteral stents are used in a variety of urological diseases and procedures. The majority of patients with indwelling ureteral stents experience bothersome symptoms and are at increased risk for urinary tract infection. Stent encrustation and the associated complications can also result in significant patient morbidity. The development of new stent designs using novel biomaterials, stent coatings and drug-eluting technologies are being applied to reduce the disadvantageous features of ureteral stents.

Is there a role for α-blockers in ureteral stent related symptoms? A systematic review and meta-analysis

PURPOSE

We evaluated the efficacy of α-blockers to improve ureteral stent related morbidity and quality of life.

MATERIALS AND METHODS

We performed a search of MEDLINE®, Embase™ and The Cochrane Library plus a hand search of conference proceedings from January 2000 to October 2010 to identify randomized, controlled trials comparing treatment for ureteral stent symptoms with α-blockers. Two reviewers independently screened studies and extracted data. Trial methodological quality was assessed by The Cochrane Collaboration quality assessment tool. Placebo randomized, controlled trials with the ureteral stent symptom questionnaire as the outcome were eligible for meta-analysis. Meta-analysis was done using the mean difference to determine the aggregate effect size.

RESULTS

A total of 12 randomized, controlled trials including 2 α-blockers in a total of 946 patients were eligible, including 4 (33%) presented only as an abstract at a urological meeting and 4 (33%) eligible for meta-analysis. Meta-analysis using a random effects model showed that α-blockers were associated with a significant decrease in urinary symptoms (MD -6.76, 95% CI -11.52 to -2.00, p=0.005), a significant decrease in pain (MD -3.55, 95% CI -5.51 to -1.60, p=0.0004) and significant improvement in general health (MD -1.90, 95% CI -3.05 to -0.75, p=0.001). However, they were not associated with a benefit in work (MD 2.41, 95% CI -1.62 to 6.44, p=0.24) or sexual matters (MD 0.20, 95% CI -1.06 to 1.45, p=0.33). Eight studies were not included in the meta-analysis, of which 7 showed a significant clinical decrease in urinary symptoms and pain.

CONCLUSIONS

Existing evidence from randomized, controlled trials shows that α-blockers are associated with improvement in ureteral stent symptoms and supports their use in routine clinical practice.

Ureteral stent discomfort: Etiology and management

Objectives:

To review the evidence-based literature on the causes, characteristics, and options to manage double J stent-related symptoms.

Methods:

We performed a Medline database assessment on papers that investigated the prevalence, mechanisms, risk factors, bothersome and management of double-J stent-related symptoms. Articles in English were reviewed and summarized.

Results:

Stent-related symptoms have a high prevalence and may affect over 80% of patients. They include irritative voiding symptoms including frequency, urgency, dysuria, incomplete emptying; flank and suprapubic pain; incontinence, and hematuria. Assessment tools are important to determine their intensity and allow for comparisons between different points in the timeline. The Urinary Stent Symptom Questionnaire (USSQ) is the most proper tool used for this purpose. Management should be focused on the prevention and management of symptoms. In this sense, research has focused on new materials and stent designs that would be more compatible to the physiologic properties of the urinary tract and medications that can ameliorate the sensitivity and motor response of the bladder.

Conclusions:

Stent-related symptoms are very common in the Urological clinical setting. It is of major importance for the urologist to understand their physiopathology and to be familiar with ways to avoid or manage them.

Combined electrohydraulic and holmium: YAG laser ureteroscopic nephrolithotripsy of large (>2 cm) renal calculi

Percutaneous nephrolithotripsy (PCL) is a standard treatment for renal calculi >2 cm. Modern flexible ureteroscopes and accessories employing the complementary effects of electrohydraulic lithotripsy (EHL) and Ho:YAG laser lithotrites can treat these renal calculi in a minimally invasive fashion with similar or superior results.

Ureteral stent symptoms and associated infections: a biomaterials perspective

Ureteral stents are commonly used in the field of urology, and, given their indwelling nature, are often a nidus for infection and a cause of discomfort. To minimize symptoms, the urologic surgeon should first consider whether a stent needs to be placed at all. Softer stents do not seem to improve patient comfort. Stents that are too long, specifically those that cross the midline of the bladder, significantly increase the frequency of stent-related symptoms. Administering alpha blockers while the stent is indwelling can reduce these symptoms. Antibiotic prophylaxis or concomitant antibiotic administration does not seem to reduce the incidence of stent-related urinary tract infection. At present, drug-eluting stents have shown the most promise for inhibiting bacterial adhesion and biofilm formation. Future stent designs that maintain drainage of the kidney and ureter while minimizing inflammation and contact with the urothelium will improve patient outcomes. By better understanding the basic pathways of bacterial adhesion to biomaterials, new stents and medications that target these mechanisms can be developed to eliminate bacterial adhesion and infection in patients with ureteral stents.

Adjuvant therapy after surgical stone management

The aim of this article was to review the most widely researched adjuvant medical therapies for the surgical management of urolithiasis. Articles were identified and reviewed from PubMed and Medline databases with MeSH headings focusing on the various surgical treatments of urolithiasis and adjuvant therapy. Additional articles were retrieved from references and conference proceedings. Surgical treatments reviewed included shockwave lithotripsy, ureteroscopy, and percutaneous nephrolithotomy. Adjuvant therapy was considered medical or complementary therapy as an adjunct to these surgical interventions. Adjuvant therapy for the surgical management of urolithiasis has been documented to increase stone-free rates, reduce stone remission rates, prevent renal damage, and decrease postoperative morbidity. A variety of agents have been studied, ranging from antioxidants to alpha-blockers and to alkalinizing agents. Additionally, there is increasing interest in complementary adjuvant therapy (ie, acupuncture). Adjuvant therapy is a fertile area for research in the surgical management of urolithiasis. The optimal agents have yet to be determined and therefore further investigation is warranted and necessary.

In vitro simulation of stent fracture mechanisms in ureteric nitinol wire stents

The ZebraStent is a new-concept lumen-less teflon-coated nitinol double-J wire-stent, designed to facilitate the passage of residual fragments after extracorporeal shock wave lithotripsy. In clinical practice we observed a small number of stent fractures. Hence, an experimental model was designed to simulate the physical forces that may lead to material fatigue of the stent. Flexion force was simulated by "half circular kidney mimicking structures" (HCKMS) into which the upper part of the stent was placed. All experiments were done for a minimum of 5 million cycles representing a stent indwelling time of 9 months, or until stent fracture, and simulating respiratory kidney movement. It was demonstrated that as the diameter of the HCKMS decreases, thus leading to an increased bending of the stent, the likelihood of stent fracture increased proportionally and occurred earlier. From our results it appears that stent fractures can be avoided by observing a maximum indwelling time of 6-8 weeks (which should suffice for the duration of a average SWL treatment), by choosing the correct (and shortest possible) stent length, and perhaps by manufacturer's modifications decreasing the stent's resistance to flexion. The ZebraStent concept remains appealing if it is considered as a short-term stent for post-SWL residual fragments.

[Ureter drugs]

Many improvements have been made recently in the field of the ureteral smooth muscle pharmacology. After a brief summary on physiological basis, we review what is known about effects on ureter of different drugs class. In a second part, we review clinical applications for renal colic analgesia, calculi expulsive medical therapy, ESWL adjuvant treatment and preoperative treatment before retrograde access. There are now sufficient data on NSAID and alpha-blockers. beta-agonists, especially for beta3 selective ones, and topical drugs before retrograde access are interesting and should be further evaluated.

Combined Electrohydraulic and Holmium:YAG Laser Ureteroscopic Nephrolithotripsy of Large (Greater Than 4 cm) Renal Calculi

PURPOSE

Percutaneous nephrolithotripsy is standard treatment for renal calculi larger than 2 cm. Modern flexible ureteroscopes and accessories using the complimentary effects of electrohydraulic lithotripsy and holmium:YAG laser lithotrites can treat large (greater than 4 cm) branched renal calculi in a minimally invasive fashion with similar or superior results. This report is an assessment of the safety and efficacy of ureteroscopic nephrolithotripsy monotherapy for the management of large (greater than 4 cm) branched renal calculi in the community setting.

MATERIALS AND METHODS

A total of 16 patients with 17 branched renal calculi ranging from 41 to 97 mm (mean 65) in length and 560 to 2,425 mm2 (mean 1,169) in area underwent staged ureteroscopic nephrolithotripsy monotherapy. Obesity (body mass index greater than 30) was present in 81% and 38% were morbidly obese (body mass index greater than 40). An infectious etiology was present in 81% and hard stone components were present in 94%. All patients presented with hematuria, pain and/or recurrent urinary tract infection. Lithotripsy was performed with a single deflection flexible ureteroscope and predominantly electrohydraulic lithotripsy. Laser drilling was used (in 4) to weaken hard stones before electrohydraulic lithotripsy. Low intrarenal pressure was maintained by continuous bladder drainage and placement of a stiff safety wire. Visibility was maintained using manual pulsatile irrigation.

RESULTS

All patients were rendered pain and infection-free. No patient required a blood transfusion and there was no change in serum creatinine. Mobile stone-free status was achieved in 15 of 17 renal units (88%) with a mean of 2.4 stages and 36 of 40 (90%) procedures performed on an outpatient basis. Operative time averaged 49 minutes per stage and 115 minutes per calculus. There were 3 patients admitted for fever and 1 patient (90 years old) admitted for pneumonia 3 days postoperatively. There were also 3 patients with calculi larger than 75 mm who required ureteroscopic management of steinstrasse.

CONCLUSIONS

Staged ureteroscopic nephrolithotripsy of large renal calculi is feasible with low morbidity and stone clearance rates that compare favorably with percutaneous nephrolithotripsy.

Minimizing symptoms in patients with ureteric stents

PURPOSE OF REVIEW

The current approaches for minimizing symptoms in patients with ureteric stents were reviewed utilizing a literature search on Pubmed using the keywords stent, symptom, and ureter.

RECENT FINDINGS

Ureteral stents are widely used in urological procedures for maintaining upper urinary tract drainage to relieve obstruction, pain, or infection. Indwelling stents, however, are associated with significant morbidity such as infection, encrustation, hematuria, and bothersome symptoms. Minimizing these issues has become paramount in the design of new ureteral stents. This article will review current and novel ways to minimize stent-related morbidity.

SUMMARY

Currently, there is no ideal stent that relieves obstruction, is resistant to infection and encrustation, and is comfortable for patients. Advances in biomaterials and design will result in a more biocompatible stent that also has patient comfort in mind.