A comparative in vitro study to determine the beneficial effect of calcium-channel and alpha(1)-adrenoceptor antagonism on human ureteric activity

Prevalence and predictors of stone passage after double J stenting for symptomatic ureteral stones: a cross-sectional, real-life study

PURPOSE

To evaluate the rate of and predictors of stone passage (SP) after urgent retrograde stenting for symptomatic ureteral stones.

METHODS

We retrospectively analysed data from 249 consecutive patients presenting to the emergency department for symptomatic ureteral stones and treated with retrograde stenting. Demographic, clinical and laboratory characteristics were collected. Stones parameters were collected before stenting and SP was evaluated at 1 month with computerized tomography. Descriptive statistics and logistic regression models tested the association between predictors and SP.

RESULTS

Overall, median (IQR) age and stone diameter were 56 (45-68) years and 7.1 (4.4-9.8) mm, respectively. Stones were located in the proximal, mid and distal ureter in 102 (41.0%), 48 (19.3%) and 99 (39.8%) cases. SP was observed in 65 (26.2%) individuals. Stone diameter (3.2 vs. 7.7 mm, p < 0.001) and stone density (416 vs. 741, p < 0.001) were lower and a higher rate of distal stones (76.9% vs. 26.7%, p < 0.001) was found in the SP group compared to that with persistent stones. Multivariable logistic regression analysis showed that distal ureteral stone location (OR 7.9, p < 0.01) and lower HU (OR 0.9, p < 0.01) were associated with SP, after accounting for stone volume. Patients with a distal stone of 500 HU had a 75% probability of SP.

CONCLUSION

Stone passage occurred in 26% of patients with indwelling stent due to symptomatic ureteral stones. Lower stone density and distal stone location were independent predictors of stone passage. Patients with these criteria should be managed with follow-up imaging and stent removal instead of ureteroscopy.

Current and emerging pharmacological targets for medical expulsive therapy

The primary goals of medical expulsive therapy are to increase the rate of stone expulsion along the ureter to avoid ureteral obstruction and reduce ureteral colic and thus avoid the need for surgical and more invasive interventions. This review focussed on the findings from in vivo and in vitro animal and human studies that have investigated the pharmacological mechanisms controlling ureteral motility and their translation to current and potentially new clinically used drugs for increasing the rate of stone expulsion along the ureter. The complicated contractility profile of the ureter, which alters with age, tissue segment region, orientation and species contributes to the difficulty of interpreting studies on ureteral pharmacology, which translates to the complexity of discovering ideal drug targets for medical expulsive therapy. Nevertheless, the current drug classes clinically used for patients with stone lodgement include α₁ -adrenoceptor antagonists, calcium channel blockers and NSAIDS, whilst there are promising targets for drug development that require further clinical investigations including the phosphodiesterase type 5 enzyme, β-adrenoceptors and 5-HT receptors.

The BUSCOPAN study: a randomized-controlled non-inferiority trial of a continuous butylscopolamine infusion versus placebo in patients with a renal colic not responding to oral non-steroidal anti-inflammatory drugs

PURPOSE

To investigate whether placebo is non-inferior to continuous infusion of butylscopolamine in patients with renal colic.

METHODS

We conducted a placebo-controlled, multicenter, double-blind randomized clinical trial (RCT) including 128 patients with renal colic (confirmed by ultrasound or CT-scan). Patients were randomized to receive either continuous IV butylscopolamine 100 mg/24 h or placebo (saline). Primary outcome is the amount of opioid escape medication used, measured in doses administered. Secondary outcomes are pain measured on a Numeric Rating Scale (NRS), side effects, and time of drug administration. Non-inferiority was assessed using linear regression with robust standard errors, with non-inferiority limit set at 0.5 units of escape medication.

RESULTS

Median number of doses of escape medication was one in both groups. The number of extra doses in the placebo group compared with the butylscopolamine group was 0.05, with a 95% robust confidence interval (CI) of 0.38-0.47. Upper limit of the CI remained below the non-inferiority limit of 0.5 (p = 0.04). No differences in secondary endpoints were seen between the groups.

CONCLUSION

Placebo is non-inferior to continuous IV butylscopolamine for pain relief in patients with renal colic. Based on this study and previous evidence, there is no role for continuous butylscopolamine IV in the treatment of renal colic. Trial NL7819.

A treatment strategy to help select patients who may not need secondary intervention to remove symptomatic ureteral stones after previous stenting

PURPOSE

This study aimed at evaluating whether removal of the ureteral stent the day before scheduled secondary intervention facilitates spontaneous ureteral stone passage and thus can spare the pre-stented patient this surgery.

METHODS

Retrospective analysis of a single-centre consecutive series of 216 patients after previous stenting due to a symptomatic ureteral stone from 01/2013 to 01/2018. Indwelling stents were removed under local anaesthesia. Patients were told to filter their urine overnight. Multivariate analysis was performed to assess predictive factors for spontaneous stone passage.

RESULTS

34% (74/216) of patients had spontaneous stone passage while the stent was indwelling. Of the remaining 142 patients, 41% (58/142) had spontaneous stone passage within 24 h after stent removal. Only 84/216 (39%) patients needed secondary intervention. Multivariate logistic regression analysis of all 216 patients showed a significant association between spontaneous stone passage and smaller stone size (p < 0.001), distal stone location (p = 0.046) and stent dwell time (p = 0.02). Predictive factors for spontaneous stone passage after stent removal were smaller size (p < 0.001), distal location (p = 0.001), and stone movement while the stent was indwelling (p = 0.016). A treatment strategy was established that helps select patients suitable for conservative management.

CONCLUSIONS

The majority (61%) of ureteral stones passed spontaneously after pre-stenting; 34% while the stent was indwelling, 27% within 24 h after stent removal. Besides distal stone location, stone size (< 6 mm) and stone movement (≥ 5 cm) while the stent is indwelling indicate patients who are likely to pass their ureteral stone spontaneously after stent removal. The treatment strategy (decision tree) presented here helps identify those patients.

TRIAL REGISTRATION

https://doi.org/10.1186/ISRCTN12112914 .

Management of stent-related symptoms with the use of α-blockers: A meta-analysis

Objectives: To assess the effectiveness of α-blockers at reducing stent-related morbidity compared to placebo using the Ureteric Symptom Score questionnaire (USSQ) at particular time points as originally set by the developers of the USSQ. Materials and methods: We conducted the study following the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) guidelines. Eligible articles were identified by a search of the Medical Literature Analysis and Retrieval System Online (MEDLINE) database for the period from 1 January 2006 to 30 November 2018. The search strategy included specific keywords and only articles in English were considered eligible. A meta-analysis of randomised controlled trials was done according to methodological quality, placebo-control use, and USSQ completion at the time points of 1 and 4 weeks after insertion, and 4 weeks after stent removal. The mean differences with 95% confidence intervals were calculated for outcomes, with a P < 0.05 considered statistically significant. Results: In all, eight papers were included for analysis. At 1 week after stent insertion, α-blockers were associated with a significant decrease in the USSQ Urinary Index score (UIS), Pain Index score, General Health Index score (GHIS), Sex Index score, and Work Index score (WIS). At 4 weeks after stent insertion, α-blockers were associated with a significant decrease in the UIS, GHIS and WIS only, whilst at 4 weeks after stent removal, α-blockers were associated with a significant decrease in the UIS and GHIS. Conclusions: The oral administration of α-blockers or their combinations have been shown to relieve stent morbidity, especially during the early period of stenting. The use of selective agents can therefore be considered; however, there is still the need for uniformly designed multi-centre randomised studies. Abbreviations: MD: mean difference; QoL: quality of life; RCT: randomised controlled trial; SRS: stent-related symptoms; USSQ: Ureteric Symptom Score questionnaire.

Formation of struvite urinary stones and approaches towards the inhibition-A review

BACKGROUND

Struvite is one of the most common urinary/kidney stones, composed of magnesium ammonium phosphate (MgNHPO₄·H₂O). They are also termed as infection stones as these are associated with urinary tract infections. Numerous studies have been carried out to examine the growth and inhibition of struvite stones.

OBJECTIVE

This review summarizes various reports on the factors responsible for inducing struvite stones in the kidney and gives a detailed account of studies on inhibition of growth of struvite crystals.

RESULTS

The presence of urea-splitting bacteria such as Proteus mirabilis and alkaline pH plays a crucial role in struvite formation. In vitro inhibition of struvite stones by various chemical agents were examined mainly in artificial urine whereas inhibition by herbal extracts was studied in vitro by gel diffusion technique. Herbal extracts of curcumin, Boerhaavia diffusa Linn, Rotula aquatica and many other plants, as well as some chemicals like pyrophosphate, acetohydroxamic acid, disodium EDTA and trisodium citrate, were reported to successfully inhibit struvite formation.

CONCLUSION

The present review recapitulates various factors affecting the growth of struvite urinary stones and the inhibitory role of certain chemicals and herbal extracts. Most of the tested plants are edible hence can be easily consumed without any adverse effects whereas the side effects of chemicals are unknown due to lack of toxicity studies. Thus, the use of herbal extracts might serve as an alternate and safe therapy for prevention of struvite stones.

Effects of naftopidil on double-J stent-related discomfort: a multicenter, randomized, double-blinded, placebo-controlled study

To evaluate the effect of naftopidil 75 mg once daily for ureteral double-J (DJ) stent-related discomfort after a ureteroscopic procedure using a multicenter, randomized, double-blinded, placebo-controlled study. 100 patients with indwelled retrograde DJ ureteral stents after ureteroscopic stone removal or retrograde intrarenal surgery (RIRS) were randomized 1:1 to receive either placebo or naftopidil during the stenting period. At the time of stent removal, the Ureteral Stent Symptom Questionnaire (USSQ), the International Prostate Symptom Score and the total amount of used analgesics were reported. Of the 92 patients who completed the study, 49 patients were enrolled in the placebo group, and 43 patients in the naftopidil group. USSQ urinary symptom scores (30.90 vs. 29.23, p = 0.299) and USSQ body pain scores (22.28 vs. 19.58, respectively, p = 0.286) were lower in the naftopidil group than in the placebo group, but the difference was not significant. Multivariate analysis showed that the use of a ureteral access sheath during RIRS was the only significant predictor of postoperative DJ-related pain (OR = 2.736, p = 0.031). The use of naftopidil once daily did not significantly reduce DJ ureteral stent-related discomfort. Larger-scaled prospective studies should be conducted to evaluate the effects of naftopidil on DJ stent-related symptoms and surgeries.

Medical expulsive therapy for ureteric stones: Analysing the evidence from systematic reviews and meta-analysis of powered double-blinded randomised controlled trials

Objective

To conduct a systematic review and meta-analysis investigating the efficacy and safety of medical expulsive therapy (MET) in low risk of bias (RoB) randomised controlled trials (RCTs).

Methods

A Cochrane style systematic review was conducted on published literature from 1990 to 2016, to include low RoB and a power calculation. A pooled meta-analysis was conducted.

Results

The MET group included 1387 vs 1381 patients in the control group. The analysis reveals α-blockers increased stone expulsion rates (78% vs 74%) (P < 0.001), whilst calcium channel blockers (CCBs) had no effect compared to controls (79% vs 75%) (P = 0.38). In the subgroup analysis, α-blockers had a shorter time to stone expulsion vs the control group (P < 0.001). There were no significant differences in expulsion rates between the treatment groups and control group for stones <5 mm in size (P = 0.48), proximal or mid-ureteric stones (P = 0.63 and P = 0.22, respectively). However, α-blockers increased stone expulsion in stones >5 mm (P = 0.02), as well as distal ureteric stones (P < 0.001). The α-blocker group developed more side-effects (6.6% of patients; P < 0.001). The numbers needed to treat for α-blockers was one in 14, for stones >5 mm one in eight, and for distal stones one in 10.

Conclusion

The primary findings show a small overall benefit for α-blockers as MET for ureteric stones but no benefit with CCBs. α-blockers show a greater benefit for large (>5 mm) ureteric stones and those located in the distal ureter, but no benefit for smaller or more proximal stones. α-blockers are associated with a greater risk of side-effects compared to placebo or CCBs.

Alpha blockers in the management of ureteric lithiasis: A meta-analysis

INTRODUCTION

Effective medical expulsion for ureteric stones with α-blockers offers numerous advantages over surgical alternatives. However, its effectiveness remains uncertain and with the publication of new trial data, the available evidence requires reappraisal.

OBJECTIVE

The aim of this study was to assess the efficacy of α-blockers the management of ureteric lithiasis.

METHODS

A systematic review of the literature, with predefined search criteria, was conducted using PubMed and Embase. All randomised trials comparing α-blocker monotherapy to placebo or standard therapy were included. Stone expulsion rate was the primary outcome measure. Secondary outcome measures were time to stone expulsion, analgesic usage and pain scores. Subgroup analyses assessed individual adrenergic antagonists and variations in standard therapy. Sensitivity analysis was based on stone location, stone size, Cochrane Risk of Bias score and study protocol. Summary effects were calculated using a random-effect model and presented as Relative risks (RR) and mean differences (MD) for dichotomous and continuous outcome measures, respectively.

RESULTS

Sixty-seven studies randomising 6654 patients were included in the meta-analysis. Stone expulsion rates improved with α-blockers (RR, 1.49; 95% CI 1.38-1.61). Contrast enhanced funnel showed evidence of publication bias. Stone expulsion time was 3.99 days (CI -4.75 to -3.23) shorter with α-blockers. Similarly, patients required 106.53 mg [CI -148.20 to -64.86] less diclofenac compared with control/placebo, and had 0.80 [CI -1.07 to -0.54] fewer pain episodes. Visual Analogue Scores were also reduced, -2.43 [CI -3.87 to -0.99]. All formulations of α-antagonists all demonstrated beneficial effects over conservative treatment/placebo. Sensitivity analysis demonstrated significant effects of stone location, stone size and study design.

CONCLUSIONS AND RELEVANCE

Despite the opposing results of recently published trial, current evidence continues to demonstrate a potential benefit of α-blocker treatment particularly for distal stones over 5 mm.

Use of drug therapy in the management of symptomatic ureteric stones in hospitalised adults: a multicentre, placebo-controlled, randomised controlled trial and cost-effectiveness analysis of a calcium channel blocker (nifedipine) and an alpha-blocker (tamsulosin) (the SUSPEND trial)

BACKGROUND

Ureteric colic, the term used to describe the pain felt when a stone passes down the ureter from the kidney to the bladder, is a frequent reason for people to seek emergency health care. Treatment with the muscle-relaxant drugs tamsulosin hydrochloride (Petyme, TEVA UK Ltd) and nifedipine (Coracten(®), UCB Pharma Ltd) as medical expulsive therapy (MET) is increasingly being used to improve the likelihood of spontaneous stone passage and lessen the need for interventional procedures. However, there remains considerable uncertainty around the effectiveness of these drugs for routine use.

OBJECTIVES

To determine whether or not treatment with either tamsulosin 400 µg or nifedipine 30 mg for up to 4 weeks increases the rate of spontaneous stone passage for people with ureteric colic compared with placebo, and whether or not it is cost-effective for the UK NHS.

DESIGN

A pragmatic, randomised controlled trial comparing two active drugs, tamsulosin and nifedipine, against placebo. Participants, clinicians and trial staff were blinded to treatment allocation. A cost-utility analysis was performed using data gathered during trial participation.

SETTING

Urology departments in 24 UK NHS hospitals.

PARTICIPANTS

Adults aged between 18 and 65 years admitted as an emergency with a single ureteric stone measuring ≤ 10 mm, localised by computerised tomography, who were able to take trial medications and complete trial procedures.

INTERVENTIONS

Eligible participants were randomised 1 : 1 : 1 to take tamsulosin 400 µg, nifedipine 30 mg or placebo once daily for up to 4 weeks to make the following comparisons: tamsulosin or nifedipine (MET) versus placebo and tamsulosin versus nifedipine.

MAIN OUTCOME MEASURES

The primary effectiveness outcome was the proportion of participants who spontaneously passed their stone. This was defined as the lack of need for active intervention for ureteric stones at up to 4 weeks after randomisation. This was determined from 4- and 12-week case-report forms completed by research staff, and from the 4-week participant self-reported questionnaire. The primary economic outcome was the incremental cost per quality-adjusted life-year (QALY) gained over 12 weeks. We estimated costs from NHS sources and calculated QALYs from participant completion of the European Quality of Life-5 Dimensions health status questionnaire 3-level response (EQ-5D-3L™) at baseline, 4 weeks and 12 weeks.

RESULTS

Primary outcome analysis included 97% of the 1167 participants randomised (378/391 tamsulosin, 379/387 nifedipine and 379/399 placebo participants). The proportion of participants who spontaneously passed their stone did not differ between MET and placebo [odds ratio (OR) 1.04, 95% confidence interval (CI) 0.77 to 1.43; absolute difference 0.8%, 95% CI -4.1% to 5.7%] or between tamsulosin and nifedipine [OR 1.06, 95% CI 0.74 to 1.53; absolute difference 1%, 95% CI -4.6% to 6.6%]. There was no evidence of a difference in QALYs gained or in cost between the trial groups, which means that the use of MET would be very unlikely to be considered cost-effective. These findings were unchanged by extensive sensitivity analyses around predictors of stone passage, including sex, stone size and stone location.

CONCLUSIONS

Tamsulosin and nifedipine did not increase the likelihood of stone passage over 4 weeks for people with ureteric colic, and use of these drugs is very unlikely to be cost-effective for the NHS. Further work is required to investigate the phenomenon of large, high-quality trials showing smaller effect size than meta-analysis of several small, lower-quality studies.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN69423238. European Clinical Trials Database (EudraCT) number 2010-019469-26.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 19, No. 63. See the NIHR Journals Library website for further project information.

Comparative efficacy of tamsulosin versus nifedipine for distal ureteral calculi: a meta-analysis

OBJECTIVE

The aim of this study was to systematically compare the therapeutic effect and safety of tamsulosin with nifedipine in medical expulsive therapy for distal ureteral calculi.

METHODS

Databases, including PubMed, EMBASE, the Cochrane Library, and Clinical Trial Register Centers, were comprehensively searched. Relevant randomized controlled trials (RCTs) were selected, and quality assessment was performed according to the Cochrane Handbook. RevMan software was used to analyze the outcome measures, which consisted of expulsion rate, expulsion time, and complications.

RESULTS

Twelve RCTs consisting of 4,961 patients were included (tamsulosin group, 2,489 cases; nifedipine group, 2,472 cases). Compared with nifedipine, tamsulosin significantly increased the expulsion rate (risk ratio =1.29, 95% CI [1.25, 1.33], P<0.0001) and reduced the expulsion time (standard mean difference =-0.39, 95% CI [-0.72, -0.05], P=0.02). Regarding safety, tamsulosin was associated with fewer complications than nifedipine (risk ratio =0.45, 95% CI [0.28, 0.72], P=0.0008), and further subgroup analysis showed that tamsulosin was associated with a lower risk of both mild and moderate-to-severe complications.

CONCLUSION

On the bias of current evidence, tamsulosin showed an overall superiority to nifedipine for distal ureteral calculi <10 mm in aspects of expulsion rate, expulsion time, and safety. Tamsulosin was supposed to be the first drug to be recommended to patients willing to receive medical expulsive therapy.

After urgent drainage of an obstructed kidney by internal ureteric stenting; is ureteroscopic stone extraction always needed?

OBJECTIVES

To assess the probability of spontaneous stone passage and its predictors after drainage of obstructed kidney by JJ stent, as insertion of an internal ureteric stent is often used for renal drainage in cases of calcular ureteric obstruction.

PATIENTS AND METHODS

Between January 2011 and June 2013, patients for whom emergent drainage by ureteric stents were identified. The patients' demographics, presentation, and stone characteristics were reviewed. The primary endpoint for this study was stone-free status at the time of stent removal, where all patients underwent non-contrast spiral computed tomography (NCCT) before stent removal. Ureteroscopic stone extraction was performed for CT detectable ureteric stones at the time of stent removal. Potential factors affecting the need for ureteroscopic stone extraction at the time of stent removal were assessed using univariate and multivariate statistical analyses.

RESULTS

Emergent ureteric stents were undertaken in 196 patients (112 males, 84 females) with a mean (SD) age of 53.7 (16.2) years, for renal obstruction drainage. At the time of stent removal, 83 patients (42.3%) were stone free; with the remaining 113 patients (57.7%) undergoing ureteroscopic stone extraction. On multivariate analysis, stone width [odds ratio (OR) 15.849, 95% confidence interval (CI) 2.83; P = 0.002) and radio-opaque stones (OR 12.035, 95% CI 4.65; P < 0.001) were independent predictors of the need for ureteroscopic stone extraction at the time of stent removal.

CONCLUSION

Spontaneous ureteric stone passage is possible after emergent drainage of an obstructed kidney by ureteric stenting. Stone opacity, larger stone width, and positive preoperative urine culture are associated with a greater probability of requiring ureteroscopic stone extraction after emergent drainage by ureteric stenting.

Medical and alternative therapies in urinary tract stone disease

Nephrolithiasis is a serious problem for both patients and the health system. Recurrence stands out as a significant problem in urinary system stone disease, the prevalence of which is increasing gradually. If recurrence is not prevented, patients may go through recurrent operations due to nephrolithiasis. While classical therapeutic options are available for all stone types, the number of randomized controlled studies and extensive meta-analyses focusing on their efficiency are inadequate. Various alternative therapeutic options to these medical therapies also stand out in recent years. The etiology of urolithiasis is multifactorial and not always related to nutritional factors. Nutrition therapy seems to be useful, either along with pharmacological therapy or as a monotherapy. General nutrition guidelines are useful in promoting public health and developing nutrition plans that reduce the risk or attenuate the effects of diseases affected by nutrition. Nutrition therapy involves the evaluation of a patient’s nutritional state and intake, the diagnosis of nutrition risk factors, and the organization and application of a nutrition program. The main target is the reduction or prevention of calculus formation and growth via decreasing lithogenic risk factors and increasing lithogenic inhibitors in urine. This review focuses briefly on classical medical therapy, along with alternative options, related diets, and medical expulsive therapy.

Effects of α-Blockers, Antimuscarinics, or Combination Therapy in Relieving Ureteral Stent-Related Symptoms: A Meta-Analysis

PURPOSE

We evaluated the effects of α-blockers, antimuscarinics, or a combination of both in reducing ureteral stent-related symptoms.

METHODS

The relevant studies were identified by searching MEDLINE, EMBASE and Cochrane Library Database from January 2000 to May 2014. Randomized controlled trials evaluating effects of α-blocker, antimuscarinic, and combination therapy for stent-related symptoms were included. Two reviewers independently screened studies and extracted data.

RESULTS

A total of 13 articles were identified including 1408 patients. There were statistically significant differences in urinary symptom (-6.37; P<0.0001) and body pain index score (-7.03; P=0.0008) of the Ureteral Stent Symptom Questionnaire (USSQ), total International Prostate Symptom Score (IPSS) (-4.16; P=0.0006), Visual Analogue Pain Scale (VAPS) score (-2.48; P<0.00001), and quality of life (QoL) (-1.42; P=0.0009) in favor of the α-blocker group. Antimuscarinics alone vs the control group showed significant improvement in total IPSS (mean difference [MD]: -3.76; 95% confidence interval [CI], -5.08 to -2.43; P<0.00001) and QoL (MD: -0.82; 95% CI, -1.31 to -0.32; P=0.001). Compared with α-blockers monotherapy, combination therapy has significant lower total IPSS (MD: -3.74; 95% CI, -4.94 to -2.54; P<0.00001), VAPS (MD: -0.50; 95% CI, -0.89 to -0.11; P=0.01), and QoL (MD: -0.93; 95% CI, -1.30 to -0.55; P<0.00001).

CONCLUSIONS

Our data showed the beneficial effect of α-blockers alone and antimuscarinics alone in reducing stent-related symptoms. Furthermore, we suggested significant advantages of combination therapy of α-blocker and antimuscarinic compared with α-blocker monotherapy. However, more high quality, randomized controlled trials are warranted to better address this issue, however.

Ureteral stent-associated complications--where we are and where we are going

Ureteral stents are one of the most commonly used devices in the treatment of benign and malignant urological diseases. However, they are associated with common complications including encrustation, infection, pain and discomfort caused by ureteral tissue irritation and possibly irregular peristalsis. In addition, stent migration and failure due to external compression by malignancies or restenosis occur, albeit less frequently. As these complications restrict optimal stent function, including maintenance of adequate urine drainage and alleviation of hydronephrosis, novel stent materials and designs are required. In recent years, progress has been made in the development of drug-eluting expandable metal stents and biodegradable stents. New engineering technologies are being investigated to provide stents with increased biocompatibility, decreased susceptibility to encrustation and improved drug-elution characteristics. These novel stent characteristics might help eliminate some of the common complications associated with ureteral stenting and will be an important step towards understanding the behaviour of stents within the urinary tract.

Effect of Flos carthami Extract and α 1-Adrenergic Antagonists on the Porcine Proximal Ureteral Peristalsis

Traditional Chinese medicine (TCM) has been proposed to prevent urolithiasis. In China, Flos carthami (FC, also known as Carthamus tinctorius) (Safflower; Chinese name: Hong Hua/紅花) has been used to treat urological diseases for centuries. We previously performed a screening and confirmed the in vivo antilithic effect of FC extract. Here, ex vivo organ bath experiment was further performed to study the effect of FC extract on the inhibition of phenylepinephrine (PE) (10⁻⁴ and 10⁻³ M) ureteral peristalsis of porcine ureters with several α₁-adrenergic antagonists (doxazosin, tamsulosin, and terazosin) as experimental controls. The results showed that doxazosin, tamsulosin, and terazosin dose (approximately 4.5 × 10⁻⁶ − 4.5 × 10⁻¹  μg/mL) dependently inhibited both 10⁻⁴ and 10⁻³ M PE-induced ureteral peristalsis. FC extract achieved 6.2% ± 10.1%, 21.8% ± 6.8%, and 24.0% ± 5.6% inhibitions of 10⁻⁴ M PE-induced peristalsis at doses of 5 × 10³, 1 × 10⁴, and 2 × 10⁴  μg/mL, respectively, since FC extract was unable to completely inhibit PE-induced ureteral peristalsis, suggesting the antilithic effect of FC extract is related to mechanisms other than modulation of ureteral peristalsis.

A comparison of nifedipine and tamsulosin as medical expulsive therapy for the management of lower ureteral stones without ESWL

Administration of nifedipine or tamsulosin has been suggested to augment stone expulsion rates. We aimed to compare the stone expulsion rates and adverse effects associated with the use of nifedipine or tamsulosin as medical expulsive therapy (MET) for the management of lower ureteral stones (LUS) without extracorporeal shock wave lithotripsy (ESWL) via a literature review and meta-analysis. Relevant randomized controlled trials (RCTs) were identified from the Medline, EMBASE, Cochrane CENTRAL, and Google Scholar databases. Finally, a total of 7 RCTs with 3897 patients were included. Our meta-analysis showed that tamsulosin could significantly increase the stone expulsion rate relative to nifedipine in patients with LUS (random-effects model; risk ratio [RR] = 0.81; 95% confidence interval [CI] = 0.75–0.88; P < 0.00001). The subgroup analysis indicated no statistically significant difference between the drugs with regard to minor or major adverse effects (fixed-effect model; RR = 1.19, 95% CI = 0.91–1.54, P = 0.20; and RR = 1.63, 95% CI = 0.22–11.82, P = 0.63, respectively). This meta-analysis demonstrated that tamsulosin was more effective than nifedipine in patients with LUS, as evidenced by the higher stone expulsion rate. Tamsulosin treatment should therefore be considered for patients with LUS.

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.

Kidney stones: an update on current pharmacological management and future directions

INTRODUCTION

Kidney stones are a common problem worldwide with substantial morbidities and economic costs. Medical therapy reduces stone recurrence significantly. Much progress has been made in the last several decades in improving therapy of stone disease.

AREAS COVERED

This review discusses i) the effect of medical expulsive therapy on spontaneous stone passage, ii) pharmacotherapy in the prevention of stone recurrence and iii) future directions in the treatment of kidney stone disease.

EXPERT OPINION

Fluid intake to promote urine volume of at least 2.5 L each day is essential to prevent stone formation. Dietary recommendations should be adjusted based on individual metabolic abnormalities. Properly dosed thiazide treatment is the standard therapy for calcium stone formers with idiopathic hypercalciuria. Potassium alkali therapy is considered for hypocitraturia, but caution should be taken to prevent potential risk of calcium phosphate stone formation. For absorptive hyperoxaluria, low oxalate diet and increased dietary calcium intake are recommended. Pyridoxine has been shown effective in some cases of primary hyperoxaluria type I. Allopurinol is used in calcium oxalate stone formers with hyperuricosuria. Treatment of cystine stones remains challenging. Tiopronin can be used if urinary alkalinization and adequate fluid intake are insufficient. For struvite stones, complete surgical removal coupled with appropriate antibiotic therapy is necessary.

Fluids and diuretics for acute ureteric colic

BACKGROUND

Acute ureteric colic is commonly associated with severe and debilitating pain. Theoretically, increasing fluid flow through the affected kidney might expedite stone passage, thereby improving symptoms more quickly. The efficacy and safety of interventions such as high volume intravenous (IV) or oral fluids and diuretics aimed at expediting ureteric stone passage is, however, uncertain.

OBJECTIVES

To look at the benefits and harms of diuretics and high volume (above maintenance) IV or oral fluid therapy for treating adult patients presenting with uncomplicated acute ureteric colic.

SEARCH METHODS

We searched the Cochrane Renal Group's specialised register (3 January 2012). Previously we searched the Cochrane Central Register of Controlled Trials (CENTRAL The Cochrane Library), MEDLINE (from 1966), EMBASE (from 1980) and handsearched reference lists of nephrology and urology textbooks, review articles, relevant studies, and abstracts from nephrology scientific meetings.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs (including the first period of randomised cross-over studies) looking at diuretics or high volume IV or oral fluids for treating uncomplicated acute ureteric colic in adult patients presenting to the emergency department for the first time during that episode were included.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Statistical analyses were performed using the random-effects model for multiple studies of the same outcomes, otherwise the fixed-effect model was used. Results were expressed as risk ratios (RR) for dichotomous outcomes or as mean differences (MD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

Two studies (enrolling 118 participants) examined the association between intense hydration and ureteric colic outcomes. There was no significant difference in pain at six hours (1 study, 60 participants: RR 1.06, 95% CI 0.71 to 1.57), surgical stone removal (1 study, 60 participants: RR 1.20, 95% CI 0.41 to 3.51) or manipulation by cystoscopy (1 study, 60 participants: RR 0.67, 95% CI 0.21 to 2.13) when no fluids over six hours was compared to three litres IV fluids administered over a six hour period. There was no difference in stone clearance (1 study 43 participants: RR 1.38, 95% CI 0.50 to 3.84), hourly pain score or patients' narcotic requirements (P > 0.05 for all comparisons) when forced IV hydration of two litres over four hours was compared with minimal IV hydration at 20 mL/hour.One study did not provide any details which would have allowed us to assess any of the risk of bias items (selection, detection, performance, attrition or reporting bias). The second study did not report the method of randomisation or allocation (selection bias - unclear), they reported that the patients were blinded to therapy (low risk of bias), analgesics were administered according to predetermined pain score criteria (low risk), and assessment of stone passage was unlikely to have been biased by knowledge of group assignment (low risk). However the second study also reported a high percentage of participants excluded post randomisation (26%; high risk of bias). We were unable to assess or ascertain any of the other risk of bias items.

AUTHORS' CONCLUSIONS

We found no reliable evidence in the literature to support the use of diuretics and high volume fluid therapy for people with acute ureteric colic. However, given the potential positive therapeutic impact of fluids and diuretics to facilitate stone passage, the capacity of these interventions warrants further investigation to determine safety and efficacy profiles.

Efficacy of tamsulosin oral controlled absorption system after extracorporeal shock wave lithotripsy to treat urolithiasis

OBJECTIVE

To determine the efficacy of the tamsulosin oral controlled absorption system as an adjuvant therapy to extracorporeal shock wave lithotripsy (ESWL) for the expulsion of ureteral and renal stones.

METHODS

A consecutive sample of 248 patients with ureteral or renal stones who underwent ESWL in an academic hospital was included in a 12-week, prospective, open-label, randomized clinical trial. Of the 248 patients, 186, including 77 with ureteral stones (mean size 9 mm) and 109 with renal stones (mean size 13 mm) completed the study. After successful ESWL, the patients were randomized to standard medical care (corticosteroids and analgesics) or standard care plus the tamsulosin oral controlled absorption system 0.4 mg/d for 1 month. The stone clearance rate, interval to the elimination of stone fragments, incidence of renal colic, and the need for rehospitalization were assessed at 4, 8, and 12 weeks.

RESULTS

The stone clearance rate was significantly greater for the patients treated with tamsulosin than for those in the standard care group at 4 (73.4% vs 55.9%, respectively; P < .001) and 12 (91.3% vs 74.6%, respectively; P < .05) weeks. Tamsulosin treatment was also associated with a significantly lower interval to the elimination of stone fragments (P < .001), a significantly lower rehospitalization rate (P < .001), and a significantly lower proportion of patients with acute renal colic (P < .05) than standard care alone. No severe adverse events leading to treatment discontinuation were observed.

CONCLUSION

Adjuvant treatment with tamsulosin, in addition to standard treatment with steroids and analgesics, improved the outcome of ESWL.

Emergency management of ureteral stones: Recent advances

Most ureteral stones can be observed with reasonable expectation of uneventful stone passage. When an active ureteral stone treatment is warranted, the best procedure to choose is dependent on several factors, besides stone size and location, including operators’ experience, patients’ preference, available equipment and related costs. Placement of double-J stent or nephrostomy tube represents the classical procedures performed in a renal colic due to acute ureteral obstruction when the conservative drug therapy does not resolve the symptoms. These maneuvers are usually followed by ureteroscopy or extracorporeal shockwave lithotripsy, which currently represent the mainstay of treatment for ureteral stones. In this review paper a literature search was performed to identify reports dealing with emergency management of renal colic due to ureteral stones. The main aspects related to this debated issue are analyzed and the advantages and disadvantages of each treatment option are carefully discussed.

Meta-analysis showing the beneficial effect of α-blockers on ureteric stent discomfort

What's known on the subject? and What does the study add? Ureteric stents cause significant discomfort and this is probably related to ureteric smooth muscle spasm and trigonal irritation. Alpha-adrenoceptor antagonists reduce smooth muscle activity and are already widely used in medical expulsive therapy to aid passage of ureteric calculi. This meta-analysis incorporating five randomized controlled trials provides evidence that alpha-adrenoceptor antagonists reduce stent-related pain and storage symptoms as assessed by the Ureteric Stent Symptoms Questionnaire (USSQ).

OBJECTIVES

• To evaluate the efficacy of α-blockers with respect to improving stent-related symptoms. • Ureteric stents remain a source of marked discomfort and their placement is often required after certain ureteroscopic procedures or in the acute setting. This analysis identifies and reviews the several studies that have investigated the role of α-blockers after stent placement.

MATERIALS AND METHODS

• Pubmed/Medline, EMBASE, CINAHL and Cochrane Library databases were scrutinized using standard MeSH headings. • Randomized or controlled trials comparing α-blockers with control or standard therapy were included. • In all studies, patients completed the Ureteral Stent Symptom Questionnaire (USSQ). • The study data were independently reviewed by two assessors.

RESULTS

• In total, five studies of varying quality were identified, including 461 patients receiving either tamsulosin or alfuzosin, or control. • On meta-analysis, all five studies showed a reduction in USSQ urinary symptom score and body pain scores. There was mean reduction of 8.4 (95% CI, 5.6-11.1) in the urinary symptom score and 7.2 (95% CI, 2.5-11.8) in the body pain score. • In three studies, the numbers of patients experiencing stent related pain were stated: 45% (51/114) of patients receiving an α-blocker experienced painful episodes within the follow-up period defined for that study compared to 76% (88/116) in the control groups, which is equivalent to a relative risk of pain of 0.59 (95% confidence interval, 0.47-0.71). • There were also reductions in other aspects of the USSQ, such as the general health score and sexual matters score, although these were not statistically significant or uniformly reported.

CONCLUSION

• There is evidence that α-blockers provide an improvement in discomfort after placement of a ureteric stent.

Visceral pain originating from the upper urinary tract

Pain originating from the upper urinary tract is a common problem and stone colic is one of the most intense pain conditions that can be experienced in the clinic. The pain is difficult to alleviate and often leads to medical attention. In humans, pain mechanisms of the upper urinary tract pain are still poorly understood, which often leads to a trial and error approach in clinical pain management. Pain from the upper urinary tract seems to have all the characteristics of pure visceral pain, including referred pain with or without hyperalgesia/trophic changes in somatic tissues and viscero-visceral hyperalgesia. However, further studies are needed to better understand these visceral pain mechanisms with regard to optimising pain management. This review gives an introduction to visceral pain in general and upper urinary tract pain in particular, with special reference to pain pathways and pharmacological and non-pharmacological pain modulation.

The Role of Non-Steroidal Anti-Inflammatory Drugs in Renal Colic

NSAIDs provide optimal analgesia in renal colic due to the reduction in glomerular filtration and renal pelvic pressure, ureteric peristalsis and ureteric oedema. Prevention of glomerular afferent arteriolar vasodilatation renders these patients at risk of renal impairment. NSAIDs have the additional benefit of reducing the number of new colic episodes and preventing subsequent readmission to hospital. Despite recent work promoting the use of pharmacological agents to improve stone passage rates, NSAIDs do not appear to reduce the time to stone passage or increase the likelihood of stone passage in renal colic.

Tamsulosin versus Alfuzosin in the Treatment of Patients with Distal Ureteral Stones: Prospective, Randomized, Comparative Study

Purpose

We evaluated and compared the efficacy of tamsulosin and alfuzosin in the medical treatment of symptomatic, uncomplicated distal ureteral stones.

Materials and Methods

A total of 87 patients with distal ureteral stones of ≤10 mm were randomly divided into 3 groups. Group I patients (n=29) received 0.4 mg tamsulosin daily, group II patients (n=30) received 10 mg alfuzosin daily, and group III patients (n=28) were not given tamsulosin or alfuzosin. Patients in all groups received Diclofenac sodium regularly for 1 week and then on demand. Follow-up was done on a weekly basis for 30 days.

Results

The mean stone size was comparable in the 3 groups (4.97±2.24, 5.47±2.13, and 5.39±1.81 mm, respectively). The stone expulsion rate was 86.2%, 76.6%, and 50% in groups I, II, and III, respectively. The difference in groups I and II with respect to group III was significant (p=0.0028 and 0.035). The mean expulsion time for groups I to III was 7.52±7.06, 8.26±7.34, and 13.90±6.99 days, respectively. The expulsion time was significantly shorter in groups I and II than in group III (p=0.0097 and 0.026). Patients taking tamsulosin and alfuzosin had fewer pain attacks than did group III patients (1.24±0.57 vs. 1.43±0.67 vs. 1.75±1.17). Only 3 cases of drug side effects, 2 in group I and 1 in group II, were recorded.

Conclusions

The use of tamsulosin or alfuzosin for the medical treatment of lower ureteric stones proved to be safe and effective. Moreover, tamsulosin did not have any significant benefits over alfuzosin.

Ureteral motility

The pyeloureteral function is to transport urine from the kidneys into the ureter toward the urinary bladder for storage until micturition. A set of mechanisms collaborates to achieve this purpose: the basic process regulating ureteral peristalsis is myogenic, initiated by active pacemaker cells located in the renal pelvis. Great emphasis has been given to hydrodynamic factors, such as urine flow rate in determining the size and pattern of urine boluses which, in turn, affect the mechanical aspects of peristaltic rhythm, rate, amplitude, and baseline pressure. Neurogenic contribution is thought to be limited to play a modulatory role in ureteral peristalsis. The myogenic theory of ureteral peristalsis can be traced back to Engelmann (1) who was able to localize the peristaltic pressure wave's origin in the renal pelvis and suggested that the ureteral contraction impulse passes from one ureteral cell to another, the whole ureter working as a functional syncitium. Recent studies of ureteral biomechanics, smooth muscle cell electrophysiology, membrane ionic currents, cytoskeletal components and pharmacophysiology much improved our understanding of the mechanism of how the urine bolus is propelled, how this process is disturbed in pathological states, and what could be done to improve it.

Medical therapy to facilitate the passage of stones: what is the evidence?

CONTEXT

Medical expulsive therapy (MET) for urolithiasis has gained increasing attention in the last years. It has been suggested that the administration of alpha-adrenoreceptor antagonists (alpha-blockers) or calcium channel blockers augments stone expulsion rates and reduces colic events.

OBJECTIVE

To evaluate the efficacy and safety of MET with alpha-blockers and calcium channel blockers for upper urinary tract stones with and without prior extracorporeal shock wave lithotripsy (ESWL).

EVIDENCE ACQUISITION

A systematic review of the literature was performed in Medline, Embase, the Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews searched through 31 December 2008 without time limit. Efficacy and safety end points were evaluated in 47 randomised, controlled trials assessing the role of MET. Meta-analysis was conducted using Review Manager (RevMan) v.5.0 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark).

EVIDENCE SYNTHESIS

Pooling of alpha-blocker and calcium channel blocker studies demonstrated a higher and faster expulsion rate compared to a control group (risk ratio [RR]: 1.45 vs 1.49; 95% confidence interval [CI]: 1.34-1.57 vs 1.33-1.66). Similar results have been obtained after ESWL (RR: 1.29 vs 1.57; 95% CI: 1.16-1.43 vs 1.21-2.04). Additionally, lower analgesic requirements, fewer colic episodes, and fewer hospitalisations were observed within treatment groups.

CONCLUSIONS

Pooled analyses suggest that MET with alpha-blockers or calcium channel blockers augments stone expulsion rates, reduces the time to stone expulsion, and lowers analgesia requirements for ureteral stones with and without ESWL for stones < or = 10 mm. There is some evidence that a combination of alpha-blockers and corticosteroids might be more effective than treatment with alpha-blockers alone. Renal stones after ESWL also seem to profit from MET. The vast majority of randomised studies incorporated into the present systematic review are small, single-centre studies, limiting the strength of our conclusions. Therefore, multicentre, randomised, placebo-controlled trials are needed.

Medical therapy of stone disease: from prevention to promotion of passage options

Medical therapy has been used for many years in the prevention of urinary stones. Medications directed at correcting urinary metabolic abnormalities responsible for promoting stone formation include thiazide diuretics, citrate salts, and allopurinol. All have proven to be efficacious. In addition, intake of citrate-rich juices, such as lemonade, may help to reduce urinary stone formation. More recently, there has been increasing interest in and use of medical therapy to aide in the passage of ureteral stones. Medical expulsive therapy (MET) has been shown to be cost effective compared with observation followed by treatment. Alpha-adrenergic receptor blockers are most commonly prescribed to promote passage of ureteral stones. They are able to facilitate stone passage, reduce time to passage, and decrease pain. Calcium-channel blockers also increase stone-passage rates. Steroids are useful adjuncts in MET.

[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.

Pharmacological management of renal colic in the older patient

Renal colic affects up to 12% of the population. Initial management of most patients is expectant. Acute symptom management of renal colic is best accomplished with a combination of parenteral opioids and NSAIDs. The elderly patient with a kidney stone should be screened for contraindications to NSAID therapy, such as renal failure or previous peptic ulcer disease. Use of parenteral opioids is often necessary during the acute setting, and downward-adjusted doses and monitoring are necessary to prevent associated confusion and respiratory depression. Novel therapy with desmopressin may also be effective for symptom control at the initial presentation, without the adverse effects of opioids or NSAIDs. However, use of desmopressin in the elderly must be undertaken cautiously, given the potential adverse effects of this agent. Many small, distal ureteral stones are treated initially with watchful waiting for the first 2-4 weeks after presentation. The patient should have effective, non-parenteral analgesics for use at home. Included in these agents are oral or suppository NSAIDs and oral opioids. Medical expulsion therapy with alpha-adrenoceptor antagonists or calcium channel antagonists is efficacious. alpha-Adrenoceptor antagonists such as the alpha(1A/)(1)(D)-selective tamsulosin are well tolerated in the elderly and increase the rate of spontaneous stone passage by approximately 50% for small distal stones. These agents also appear to decrease the severity of renal colic. Corticosteroids and calcium channel antagonists are also effective but their use in the elderly is not recommended as first-line therapy.