Evidence for the presence of alpha1 adrenoceptor subtypes in the human ureter

Does mirabegron have a potential role as a medical expulsive therapy in the treatment of distal ureteral stones? A prospective randomized controlled study

BACKGROUND

The existence of β3 receptors in the bladder and ureter was documented in many studies on animals and humans, it was documented that relaxation of the lower ureteral segment is achieved by the stimulation of these receptors. Our aim was to assess the efficacy and safety of mirabegron as a medical expulsive therapy (MET) for distal ureteral stones in comparison with silodosin and placebo.

METHODS

One hundred eighty patients with distal ureteral stone of 5-10 mm size were included in our study. They were divided into three groups, and each one consisted of 60 patients. Group I was given silodosin 8 mg, group II mirabegron 50 mg and group III placebo once daily. The treatment was prescribed for all the cases till stone expulsion or a maximum duration of 4 weeks. Primary outcome was the stone expulsion rate (SER). While secondary outcomes were stone expulsion time, side effects of the used drugs, hospital visits number for pain, and amount of analgesic taken.

RESULTS

We found that the SER was significantly higher in silodosin than mirabegron and placebo groups (61%, 38.6%, and 36.7%, respectively) (p = 0.013). Also, the stone expulsion interval was significantly shorter in silodosin than mirabegron and control groups (p < 0.001). While hospital visits number for pain, and amount of analgesic taken were comparable. There was no difference between the studied medications in terms of the adverse effects except for retrograde ejaculation (silodosin = 63.3%, mirabegron = 0%, and placebo = 0%; p < 0.001).

CONCLUSION

Mirabegron has no medical expulsive effect. While silodosin improves SER and stone expulsion time. However, retrograde ejaculation was its main side effect and occurred in 63.3% of the male patients. Therefore, more research is needed to discover a more tolerable MET.

Tamsulosin Versus Mirabegron in Relieving Ureteric Stent-Related Symptoms: A Prospective, Double-Blinded, Randomized Controlled Trial

Introduction Alpha-adrenergic blockers like tamsulosin are widely used in the treatment of stent-related symptoms due to ureteric stents. Recently, mirabegron has emerged as a potential alternative. So, our study aimed to compare the effect of mirabegron and tamsulosin on ureteric stent-related morbidity. Methods In this randomized controlled study, 80 patients undergoing uncomplicated ureteroscopic lithotripsy with double J stenting for ureteric stones were enrolled. They were divided into two groups: Group A (n=40) received mirabegron (25mg) and Group B (n=40) received tamsulosin (0.4mg). Outcomes were assessed using the Ureteral Stent Symptom Questionnaire (USSQ), International Prostate Symptoms Score (IPSS), and the visual analog pain scale. The t-test and the Chi-square test were utilized to study the efficacy of the interventions across both groups. Results The USSQ urinary symptom score (25.5 vs 33.45; p < 0.001) and body pain score (16.15 vs 26.02; P < 0.001) were significantly lower in the mirabegron group. However, the general health score (17.0 vs 17.28; p = 0.62) and work performance score (7.6 vs 8.0; p = 0.28) did not show a significant difference. The storage symptom score was significantly lower in the mirabegron group (3.98 vs 5.1; p = 0.001). Furthermore, the mirabegron group reported a better quality of life score (2.18 vs 3; p < 0.001). Conclusion Mirabegron has been shown to reduce urinary symptoms associated with ureteric stents and also results in a better quality of life when compared with tamsulosin. However, large-scale, prospective, multicentric studies are further required to holistically evaluate and comprehend the beneficial effects of mirabegron on stent-related morbidity.

2022 Recommendations of the AFU Lithiasis Committee: Management of symptomatic urinary stones

The acute situation, caused by an obstructive stone, is defined by a renal colic that may be uncomplicated, complicated, or at risk in specific conditions. Its management may be medical or require interventional treatment by extracorporeal shockwave lithotripsy, endoscopic removal, or ureteroscopy. METHODOLOGY: These recommendations were developed using two methods, the Clinical Practice Recommendations (CPR) and the ADAPTE method, in function of whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis) [EAU Guidelines on urolithiasis. 2022] and whether they could be adapted to the French context.

The regular use of calcium channel blockers before flexible URS appears to facilitate primary UAS insertion: a retrospective study in a single center

PURPOSE

To evaluate the effect of regular use of CCB before flexible URS for successful primary UAS insertion.

MATERIALS AND METHODS

We retrospectively analyzed 209 patients who underwent flexible ureteroscopy (URS) for upper urinary tract calculi between Jan 2021 and Dec 2021. Patients were divided into two groups based on whether calcium channel blockers (CCB) were used (n = 72) or not (n = 137). The following parameters were collected: age, sex, height and weight, BMI, stone location, stone burden, number of stones, operation time, hospital stay, hospital readmission, post-operative fever, post-operative SIRS rate, Clavien-Dindo grade, hospitalization costs, successful primary UAS insertion. We compared the two groups using Student's t test, Mann-Whitney U test and χ² test for quantitative and categorical variables, respectively. A logistic regression model was used to identify predictive factors of UAS successful primary insertion.

RESULTS

Compared with the non-CCB group, the CCB group had a higher successful primary UAS insertion rate (97.2% vs.85.4%, p = 0.008), and a lower hospital readmission rate (2.8% vs.12.4%, p = 0.021). In multivariate analyses, the regular use of CCB was the only predictive factor of successful primary UAS insertion rate (OR 6.32, 95% CI 1.41-28.29, p = 0.016).

CONCLUSION

The regular use of calcium channel blockers (CCB) before flexible URS appears to facilitate ureteral access sheaths (UAS) primary insertion.

α1-Adrenergic Receptors: Insights into Potential Therapeutic Opportunities for COVID-19, Heart Failure, and Alzheimer's Disease

α1-Adrenergic receptors (ARs) are members of the G-Protein Coupled Receptor superfamily and with other related receptors (β and α2), they are involved in regulating the sympathetic nervous system through binding and activation by norepinephrine and epinephrine. Traditionally, α1-AR antagonists were first used as anti-hypertensives, as α1-AR activation increases vasoconstriction, but they are not a first-line use at present. The current usage of α1-AR antagonists increases urinary flow in benign prostatic hyperplasia. α1-AR agonists are used in septic shock, but the increased blood pressure response limits use for other conditions. However, with the advent of genetic-based animal models of the subtypes, drug design of highly selective ligands, scientists have discovered potentially newer uses for both agonists and antagonists of the α1-AR. In this review, we highlight newer treatment potential for α1A-AR agonists (heart failure, ischemia, and Alzheimer's disease) and non-selective α1-AR antagonists (COVID-19/SARS, Parkinson's disease, and posttraumatic stress disorder). While the studies reviewed here are still preclinical in cell lines and rodent disease models or have undergone initial clinical trials, potential therapeutics discussed here should not be used for non-approved conditions.

Effect of tamsulosin versus tamsulosin plus tadalafil on renal calculus clearance after shock wave lithotripsy: An open-labelled, randomised, prospective study

Objectives

To compare the efficacy of tamsulosin versus tamsulosin plus tadalafil in achieving clearance of fragments after shock wave lithotripsy (SWL) to treat renal calculi.

Methods

Between January 2016 to December 2017, 140 patients with solitary, non-branched, non-lower calyceal renal calculus and measuring less than 20 mm and treated with SWL were randomized to tamsulosin (group A) or tamsulosin plus tadalafil (group B). Therapy was given for a period of 4 weeks. Stone clearance rate, analgesic requirement, occurrence of steinstrasse, need for auxiliary procedures (endoscopic treatment), and adverse effects of drugs were recorded.

Results

The overall clearance rate was 72.5% (50/69) in the group A and 90.1% (64/71) in the group B (p=0.007). For stones up to 12 mm, the difference in the clearance rate was significant (p=0.039) while it was not so for stones larger than 12 mm (p=0.151). There was no statistically significant difference between the two groups with regards to analgesic requirement (p=0.94), occurrence of steinstrasse (p=0.101), need for auxiliary procedures (p=0.76), and adverse effects of the drugs (p=0.148).

Conclusion

Our study shows that adjunctive medical expulsive therapy with tamsulosin and tadalafil achieves better clearance rate than tadalafil alone in patients receiving SWL for renal stones.

Comparison of efficacy of various drugs used for medical expulsive therapy for distal ureter stones: A systematic review and network meta-analysis

OBJECTIVES

Medical expulsive therapy has been found to be effective for distal ureteric stones; however, which drug is most efficacious in terms of stone expulsion rate (SER) and stone expulsion time (SET) is not known. With this review we aimed to compare the efficacy of various drug treatments for distal ureter stones used as medical expulsive therapy in terms of SER and SET.

METHODS

Systematic literature search was conducted to include all the randomised study comparing various drug interventions for lower ureter stones. Standard preferred reporting items for systematic review and meta-analysis for network meta-analysis (PRISMA-NMA) were pursued.

RESULTS

In this review, 50 randomised studies with 12,382 patients were included. For stone expulsion rate (SER), compared with placebo all the treatment groups were more effective except nifedipine and sildenafil. According to the SUCRA values obtained, naftopidil plus steroid was the highest rank and nifedipine lowest. For stone expulsion time (SET), compared with placebo only tadalafil plus silodosin, nifedipine plus steroid, alfuzosin, silodosin, tadalafil and tamsulosin were more effective. SUCRA values were highest for tadalafil plus silodosin and least for naftopidil plus steroid. From subgroup analysis with individual drugs for SER, SUCRA values were highest for naftopidil followed by silodosin and SET was highest for silodosin and least for naftopidil.

CONCLUSION

For lower ureter stone, tadalafil plus silodosin is the best combination and silodosin best individual drug considering the SET and SER. Nifedipine as monotherapy is no more effective than control group.

Role of α- and β-adrenergic signaling in phenotypic targeting: significance in benign and malignant urologic disease

The urinary tract is highly innervated by autonomic nerves which are essential in urinary tract development, the production of growth factors, and the control of homeostasis. These neural signals may become dysregulated in several genitourinary (GU) disease states, both benign and malignant. Accordingly, the autonomic nervous system is a therapeutic target for several genitourinary pathologies including cancer, voiding dysfunction, and obstructing nephrolithiasis. Adrenergic receptors (adrenoceptors) are G-Protein coupled-receptors that are distributed throughout the body. The major function of α1-adrenoceptors is signaling smooth muscle contractions through GPCR and intracellular calcium influx. Pharmacologic intervention of α-and β-adrenoceptors is routinely and successfully implemented in the treatment of benign urologic illnesses, through the use of α-adrenoceptor antagonists. Furthermore, cell-based evidence recently established the antitumor effect of α1-adrenoceptor antagonists in prostate, bladder and renal tumors by reducing neovascularity and impairing growth within the tumor microenvironment via regulation of the phenotypic epithelial-mesenchymal transition (EMT). There has been a significant focus on repurposing the routinely used, Food and Drug Administration-approved α1-adrenoceptor antagonists to inhibit GU tumor growth and angiogenesis in patients with advanced prostate, bladder, and renal cancer. In this review we discuss the current evidence on (a) the signaling events of the autonomic nervous system mediated by its cognate α- and β-adrenoceptors in regulating the phenotypic landscape (EMT) of genitourinary organs; and (b) the therapeutic significance of targeting this signaling pathway in benign and malignant urologic disease. Video abstract.

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.

Alpha-blockers after shock wave lithotripsy for renal or ureteral stones in adults

BACKGROUND

Shock wave lithotripsy (SWL) is a widely used method to treat renal and ureteral stone. It fragments stones into smaller pieces that are then able to pass spontaneously down the ureter and into the bladder. Alpha-blockers may assist in promoting the passage of stone fragments, but their effectiveness remains uncertain.  OBJECTIVES: To assess the effects of alpha-blockers as adjuvant medical expulsive therapy plus usual care compared to placebo and usual care or usual care alone in adults undergoing shock wave lithotripsy for renal or ureteral stones.

SEARCH METHODS

We performed a comprehensive literature search of the Cochrane Library, the Cochrane Database of Systematic Reviews, MEDLINE, Embase, several clinical trial registries and grey literature for published and unpublished studies irrespective of language. The date of the most recent search was 27 February 2020.

SELECTION CRITERIA

We included randomized controlled trials of adults undergoing SWL. Participants in the intervention group had to have received an alpha-blocker as adjuvant medical expulsive therapy plus usual care. For the comparator group, we considered studies in which participants received placebo.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion/exclusion, and performed data abstraction and risk of bias assessment. We conducted meta-analysis for the identified dichotomous and continuous outcomes using RevManWeb according to Cochrane methods using a random-effects model. We judged the certainty of evidence on a per outcome basis using GRADE.

MAIN RESULTS

We included 40 studies with 4793 participants randomized to usual care and an alpha-blocker versus usual care alone. Only four studies were placebo controlled. The mean age of participants was 28.6 to 56.8 years and the mean stone size prior to SWL was 7.1 mm to 13.2 mm. The most widely used alpha-blocker was tamsulosin; others were silodosin, doxazosin, terazosin and alfuzosin.  Alpha-blockers may improve clearance of stone fragments after SWL (risk ratio (RR) 1.16, 95% confidence interval (CI) 1.09 to 1.23; I² = 78%; studies = 36; participants = 4084; low certainty evidence). Based on the stone clearance rate of 69.3% observed in the control arm, an alpha-blocker may increase stone clearance to 80.4%. This corresponds to 111 more (62 more to 159 more) participants per 1000 clearing their stone fragments. Alpha-blockers may reduce the need for auxiliary treatments after SWL (RR 0.67, 95% CI 0.45 to 1.00; I² = 16%; studies = 12; participants = 1251; low certainty evidence), but also includes the possibility of no effect. Based on a rate of auxiliary treatments in the usual care arm of 9.7%, alpha-blockers may reduce the rate to 6.5%. This corresponds 32 fewer (53 fewer to 0 fewer) participants per 1000 undergoing auxiliary treatments. Alpha-blockers may reduce major adverse events (RR 0.60, 95% CI 0.46 to 0.80; I² = 0%; studies = 7; participants = 747; low certainty evidence). Major adverse events occurred in 25.8% of participants in the usual care group; alpha-blockers would reduce this to 15.5%. This corresponds to 103 fewer (139 fewer to 52 fewer) major adverse events per 1000 with alpha-blocker treatment. None of the reported major adverse events appeared drug-related; most were emergency room visits or rehospitalizations. Alpha-blockers may reduce stone clearance time in days (mean difference (MD) -3.74, 95% CI -5.25 to -2.23; I² = 86%; studies = 14; participants = 1790; low certainty evidence). We found no evidence for the outcome of quality of life. For those outcomes for which we were able to perform subgroup analyses, we found no evidence of interaction with stone location, stone size or type of alpha-blocker. We were unable to conduct an analysis by lithotripter type. The results were also largely unchanged when the analyses were limited to placebo controlled studies and those in which participants explicitly only received a single SWL session.

AUTHORS' CONCLUSIONS

Based on low certainty evidence, adjuvant alpha-blocker therapy following SWL in addition to usual care may result in improved stone clearance, less need for auxiliary treatments, fewer major adverse events and a reduced stone clearance time compared to usual care alone. We did not find evidence for quality of life. The low certainty of evidence means that our confidence in the effect estimate is limited; the true effect may be substantially different from the estimate of the effect.

Drug Repositioning of the α1-Adrenergic Receptor Antagonist Naftopidil: A Potential New Anti-Cancer Drug?

Failure of conventional treatments is often observed in cancer management and this requires the development of alternative therapeutic strategies. However, new drug development is known to be a high-failure process because of the possibility of a lower efficacy than expected for the drug or appearance of non-manageable side effects. Another way to find alternative therapeutic drugs consists in identifying new applications for drugs already approved for a particular disease: a concept named "drug repurposing". In this context, several studies demonstrated the potential anti-tumour activity exerted by α1-adrenergic receptor antagonists and notably renewed interest for naftopidil as an anti-cancer drug. Naftopidil is used for benign prostatic hyperplasia management in Japan and a retrospective study brought out a reduced incidence of prostate cancer in patients that had been prescribed this drug. Further studies showed that naftopidil exerted anti-proliferative and cytotoxic effects on prostate cancer as well as several other cancer types in vitro, as well as ex vivo and in vivo. Moreover, naftopidil was demonstrated to modulate the expression of Bcl-2 family pro-apoptotic members which could be used to sensitise cancer cells to targeting therapies and to overcome resistance of cancer cells to apoptosis. For most of these anti-cancer effects, the molecular pathway is either not fully deciphered or shown to involve α1-adrenergic receptor-independent pathway, suggesting off target transduction signals. In order to improve its efficacy, naftopidil analogues were designed and shown to be effective in several studies. Thereby, naftopidil appears to display anti-cancer properties on different cancer types and could be considered as a candidate for drug repurposing although its anti-cancerous activities need to be studied more deeply in prospective randomized clinical trials.

Animal Models for Studying Stone Disease

Animals have stone disease too. There are several animal models for the research of human stone disease. Rodents are the most frequently used for stone research, although they are not prone to forming crystals in the kidneys. Ethylene glycol (EG), sodium oxalate and l-hydroxyproline are common lithogenic agents. Dogs and pigs were also reported as a study animal for stone disease. However, the breeding costs and body size are too high. The most-used genetic study animal for stone disease was the mouse, but it was high-cost. Calcium oxalate (CaOx) crystals can also be light microscopically observed in the Malphigian tubules of Drosophila melanogaster, induced by adding EG to the food. Genetic studies of flies can be done by cross-breeding, and this has a lower cost than using mice. The fly model also has several advantages, including minimal breeding equipment, the fact that it is easier to reach larger numbers in a short time with flies, that crystals can be observed under microscopy, and that they allow genetic study. We suggest the fly will be an ideal animal model for stone research in the future.

Efficacy of Tamsulosin plus Tadalafil versus Tamsulosin as Medical Expulsive Therapy for Lower Ureteric Stones: A Randomized Controlled Trial

Introduction

Urolithiasis is one of the common disorder with which about 1/5^th is found in the ureter, of which 2/3^rd is seen in the lower ureter. Medical expulsive therapy is one of the routine modalities of treatment which uses various drugs acting on the ureter smooth muscle by different mechanism. We aim to compare the efficacy of combination vs. single drug.

Methods

This randomized controlled trial was done in 176 consecutive patients over a period of six months (March 2019 to August 2019) in Department of Urology and Kidney Transplant Surgery, Tribhuvan University Teaching. Participants were divided into two groups (Group A, tamsulosin plus tadalafil, and Group B, tamsulosin) from computer-generated random numbers. Therapy was continued for a maximum of 3 weeks. Stone expulsion rate, time to stone expulsion, analgesic use, number of colic and emergency room visits for pain, early intervention, and adverse effects of drugs were recorded.

Results

Among 176 patients who were enrolled in study, 7 were lost to follow-up, and 5 people required immediate intervention. There was a significant higher stone passage rate in group A than group B (64 vs. 50; P=0.025) and shorter expulsion time (1.66 vs. 2.32 weeks P=0.001) and less number of emergency room visits and colic episodes. No significant side effects were noted during study.

Conclusion

Tamsulosin plus Tadalafil is more effective than tamsulosin with early passage of stone and decreased number of colic episodes and emergency visits without significant side effects for lower ureteric calculi of 5 mm to 10 mm.

Efficacy of silodosin or mirabegron in medical expulsive therapy for ureteral stones: a prospective, randomized-controlled study

OBJECTIVE

To evaluate the efficacy of silodosin or mirabegron as a medical expulsive therapy for ureteric stones in adults.

PATIENTS-METHOD

This is a prospective, randomized multicentric study. Patients who had ureter stones in size between 4 and 10 mm were assessed prospectively. Patients were divided into three groups with equal randomization. Group 1 was the control group; group 2 took silodosin 8 mg, and group 3 took mirabegron 50 mg once daily.

RESULTS

All 169 patients were included in the final analysis. The spontaneous expulsion rate was similar between groups. In patients with distal localization, the stone expulsion interval was shorter in the silodosin group (7.1 ± 4.5 days) than the control (12 ± 8.7) (p = 0.034). In patients with stone size smaller than 6 mm, the stone expulsion interval was shorter in the silodosin group (5.8 ± 4) than the control (12.2 ± 2.8) (p = 0.004); the analgesic requirement was less in the silodosin group (1.4 ± 1.3) than in the control (3.6 ± 2.8) (p = 0.028). Mirabegron had no effect on stone expulsion interval in any analysis. In patients with distal localization or stone size bigger or equal to 6 mm, the need for an analgesic was less in the mirabegron group (1.8 ± 1.9) (1.9 ± 1.8) than in the control (3.6 ± 2.3) (3.2 ± 1.8), respectively (p = 0.004) (p = 0.017).

CONCLUSIONS

Silodosin or mirabegron does not improve the stone expulsion rate. Silodosin improves the stone expulsion interval and decreases the need for an analgesic or < 6 mm stones. Mirabegron has no effect on the stone expulsion interval, but decreases the need for an analgesic in patients with distal or sized ≥ 6 mm stones.

Updates in the function and regulation of α1 -adrenoceptors

α₁ -Adrenoceptors are seven transmembrane domain GPCRs involved in numerous physiological functions controlled by the endogenous catecholamines, noradrenaline and adrenaline, and targeted by drugs useful in therapeutics. Three separate genes, whose products are named α_1A -, α_1B -, and α_1D - adrenoceptors, encode these receptors. Although the existence of multiple α₁ -adrenoceptors has been acknowledged for almost 25 years, the specific functions regulated by each subtype are still largely unknown. Despite the limited comprehension, the identification of a single class of subtype-selective ligands for the α_1A - adrenoceptors, the so-called α-blockers for prostate dysfunction, has led to major improvement in therapeutics, demonstrating the need for continued efforts in the field. This review article surveys the tissue distribution of the three α₁ -adrenoceptor subtypes in the cardiovascular system, genitourinary system, and CNS, highlighting the functions already identified as mediated by the predominant activation of specific subtypes. In addition, this review covers the recent advances in the understanding of the molecular mechanisms involved in the regulation of each of the α₁ -adrenoceptor subtypes by phosphorylation and interaction with proteins involved in their desensitization and internalization. LINKED ARTICLES: This article is part of a themed section on Adrenoceptors-New Roles for Old Players. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.14/issuetoc.

In vitro study of age-related changes in human ureteral failure properties according to region, direction, and layer

Knowledge of the capacity of the ureteral wall to withstand urodynamic or external stresses is essential to understand ureteral injury and rupture that mostly occur following trauma, but may also be secondary to obstructive uropathy. It has clinical significance as well in the prevention of iatrogenic injury, for example, during ureteroscopy, but no information is available with regard to the age-related failure properties and regional differences have not been systematically described. Uniaxial tensile testing was performed on 166 ureteral rings and strips from 21 humans free of overt urologic disease; histological evaluation was performed. The degree of layer participation to the intact wall failure stress (=tissue strength), peak elastic modulus (=stiffness), and failure stretch (=extensibility) was assessed by examining layer-specific ruptures in the stress-stretch data. Failure stress at and peak elastic modulus before the first (muscle/adventitial) rupture correlated inversely less with age ( p < 0.05 in few regions/directions) than failure stress at the second (mucosal) rupture ( p < 0.05 in the middle and lower ureter), consistent with the decreased mucosal thickness in ≥50-year-old subjects. Failure stretch at both ruptures did not correlate with age ( p > 0.05 in most regions/directions), paralleling elastin content. Correlations with age were more significant in females than males. Failure stress at the second rupture point was higher ( p < 0.05) distally in <50-year-old but not in ≥50-year-old subjects, justified by the increased collagen distally in the former. Directional differences in failure stretches ( p < 0.05 at all ages/regions/genders) were justified by preferentially axial collagen reinforcement. The presented results may establish the foundation for computational models of iatrogenic/accidental ureteral trauma.

Efficacy and Safety of Ultrasonic Longitudinal-Axis Vibration for the Reduction of Ureteral Access Sheath Insertion Force: A Randomized Controlled Trial in a Porcine Model

PURPOSE

Excessive bulking force during ureteral access sheath (UAS) placement may induce injury. The sliding friction between surfaces can be reduced with the application of ultrasonic vibration. We investigated the efficacy and safety of an ultrasonic vibration transducing device for reducing the maximal ureteral access sheath insertion force (UASIF).

MATERIALS AND METHODS

A device was developed for transducing ultrasonic longitudinal-axis vibration onto the UAS at an adjustable amplitude and frequency while measuring the degree of UASIF. In the pilot study, six porcine models were used to investigate the optimal amplitude and frequency of vibration and to calculate sample size. Twelve porcine models were utilized in a randomized controlled trial. Resected ureters were pathologically evaluated for ureteral injury.

RESULTS

The transduction of ultrasonic vibration at an amplitude of 0.04 g and a frequency of 18,000 Hz resulted in a maximal UASIF reduction of 36.4% (interquartile range 32.7-43.1). Maximal UASIF tended to decrease with increasing vibration frequency. No significant differences in UASIF reductions were observed according to amplitude. In the randomized controlled trial, the maximal UASIF reduction was 37.0% (interquartile range 21.4-44.2). Grade II injury was pathologically diagnosed in 8.3% (1/12) of the ureters in both groups.

CONCLUSIONS

The transduction of ultrasonic longitudinal-axis vibration onto the UAS reduces maximal UASIF and does not harm the ureter. Reducing the velocity of sheath insertion may further reduce maximal UASIF.

Efficacy of silodosin on the outcome of semi-rigid ureteroscopy for the management of large distal ureteric stones: blinded randomised trial

Objective

To evaluate the efficacy of silodosin therapy, as a new α-adrenergic receptor (α-AR) blocker, on the success rate of semi-rigid ureteroscopy (URS) for the management of large distal ureteric stones.

Patients and methods

This prospective study recruited 127 adult patients with single distal ureteric stone of ≥1 cm. The patients were randomly allocated to two groups: the first group included 62 patients who received silodosin (8 mg) for 10 days before URS (Silodosin group), whilst the second group included 65 patients who received placebo, in the form of multivitamins, for 10 days before URS (Placebo group). All patients underwent URS and a pneumatic lithoclast was used for stone fragmentation.

Results

The mean (SD) operative time was shorter in the Silodosin group compared with the Placebo group, at 41.61 (4.67) vs 46.85 (4.6) min, respectively. Furthermore, advancing the ureteroscope to access the stone failed in a statistically significant number of patients in the Placebo group compared with the Silodosin group (13 vs two, respectively). The complication rate was significantly higher in the Placebo group compared with the Silodosin group (20% vs 6.4%, P = 0.036). Additionally, the need for postoperative analgesia was significantly lower in the Silodosin group compared with the Placebo group (8.1% vs 26.2%, P = 0.009).

Conclusion

Silodosin therapy prior to URS management of large distal ureteric stones seems to be associated with better advancing of the ureteroscope to access the stone, shorter procedure time, higher stone-free rate, lower incidence of complications, and lesser need for postoperative analgesia.

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.

On medical treatment for ureteral stone expulsion

There is evidence that α-adrenoceptor (α-AR) antagonists facilitate the passage of ureteric stones, but the mechanism behind this effect has not been established. If one accepts that it is the friction between a ureteral stone and the mucosa that hampers the passage of the stone, and that the passage traumatizes the mucosa, the aim of treatment must be to reduce this friction. Elevated pressure above an obstructing stone results in an increase in tension in the wall of the upper urinary tract, including the tension at stone level, which causes an increase in friction and ureteric colic. Reducing pressure, by low but adequate fluid intake, non-steroidal anti-inflammatory drugs (NSAIDs), or α-AR antagonists that reduce the friction and give pain relief, seems to be rational. When the stone is pressed downwards by a high pressure the mucosa forms a bar ahead of the stone. These factors reduce the ureteral lumen and hamper the passage of both urine and the stone. The swelling can be reduced by NSAIDs. Filling of the ureter ahead of the stone reduces the friction between the stone and the ureteral mucosa. Evacuation of the urine ahead of the stone by effective peristaltic activity increases this friction. α-AR antagonists that reduce peristalsis may therefore be used to reduce the friction and consequently allow the stones to pass more often and earlier. For very early stone expulsion, a combination of NSAIDs and α-AR antagonists may be useful. There is no evidence that spasm influences the passage of ureteral stones.

Outcome of uncomplicated ureteric calculi managed with medical expulsive therapy in the outpatient clinic of a urology unit in Sri Lanka

OBJECTIVE

Although medical expulsive therapy (MET) is shown to be effective for ureteric calculi, the optimum duration and the stone size suitable for MET are not well established yet. The objectives of the study were to determine the optimum duration and maximum stone size suitable for MET.

RESULTS

All patients with radiologically confirmed uncomplicated ureteric calculi treated with MET using tamsulosin over a period of 6 months in the outpatient setting were followed up. There were 213 patients. 165 were men. Mean age was 42 years. At presentation 42 stones were in upper ureter (19.7%), 51 in mid ureter (23.9%), 120 in lower ureter (56.3%). The majority (82.7%) of stones were less than 10 mm. Seven stones (3.3%) were over 15 mm. Ninety-two (43.2%) patients had spontaneous passage of stones within 6-weeks of MET. Another 38.9% passed the stone within the next 6-weeks. Thirty-eight patients (17.8%) required surgery. Uncomplicated ureteric stones up to 10 mm can be given a trial of MET using tamsulosin which can be extended up to 12-weeks with a success rate over 92%. This may have substantial clinical and fiscal benefits by reducing the number of interventional procedures especially in resource-poor settings.

A network meta-analysis on the beneficial effect of medical expulsive therapy after extracorporeal shock wave lithotripsy

We applied a newly introduced method, network meta-analysis, to re-evaluate the expulsion effect of drugs including tamsulosin, doxazosin, nifedipine, terazosin and rowatinex after extracorporeal shock wave lithotripsy (ESWL) as described in the literature. A systematic search was performed in Medline, Embase and Cochrane Library for articles published before March 2016. Twenty-six studies with 2775 patients were included. The primary outcome was the number of patients with successful stone expulsion. The data were subdivided into three groups according to duration of follow-up. A standard network model was established in each subgroup. In 15-day follow-up results, SUCRA outcome showed the ranking of effects was: doxazosin > tamsulosin > rowatinex > nifedipine > terazosin (88.6, 77.4, 58.6, 32.2 and 30.4, respectively). In 45-day follow-up results, SUCRA ranking was: tamsulosin > nifedipine > rowatinex (69.4, 67.2 and 62.6, respectively). In 90-day follow-up results, SUCRA ranking was: doxazosin > rowatinex > tamsulosin (84.1, 68.1 and 49.1, respectively). In conclusion, doxazosin and tamsulosin have potential to be the first choice for pharmacological therapy to promote the expulsion of urinary stone fragments after ESWL, with this doxazosin can improve the SFR in the long term, while tamsulosin may result more in accelerating the process of expulsion.

Do Preoperative Alpha Blockers Facilitate Ureteroscope Insertion at the Vesico-Ureteric Junction? An Answer from a Prospective Case-Controlled Study

Objective: To evaluate whether alpha blockers facilitate the navigation of the ureteroscope through the ureteric orifice, if administered preoperatively, based on the role of alpha blockers, mainly tamsulosin, in medical expulsive therapy of ureteric calculus. Methods: A prospective, case-control study of 174 patients who underwent ureteroscopic stone removal for lower or mid ureteral calculi between November 2014 and March 2016 was carried out. We included patients >14 years of age who were planned for ureteroscopic stone removal. We divided the patients into two groups, including those who were not prescribed alpha blockers prior to surgery (Group A: no alpha blocker) and those patients who were started on alpha blockers, tamsulosin 0.4 mg, 3 days prior to surgery (Group B: alpha blocker). We excluded patients with stone size >1 cm, spontaneous stone passage prior to surgery, unable to perform ureteroscopy (URS), and previous history of ureteroscopic intervention. Results: Our study included 124 patients, among whom 60 patients were prescribed alpha blockers preoperatively (Group B). The mean age of the study population was 37.62+9.74 (15–64 years) and the mean stone burden was 38.92+8.21 (15.94–58.12 mm2). The difference in rate of ureteroscope negotiation through the ureteric orifice between Groups A and B was not statistically significant (p=0.57). Conclusions: In URS, preoperative administration of alpha blockers failed to improve technical ease and lower complication rate. Further large group, multi-centre studies are required todiscover a definitive role of alpha blockers prior to URS.

To compare the efficacy of tamsulosin and alfuzosin as medical expulsive therapy for ureteric stones

Aims and Objectives:

This study aims to evaluate the efficacy of tamsulosin and alfuzosin for the distal ureteral stone. This study assessed the spontaneous passage and expulsion of the stone.

Materials and Methods:

The study was conducted in the Department of Surgery at Maharishi Markandeshwar Institute of Medical Sciences and Research, Mullana, Ambala, from May 2013 to May 2014. A total number of 136 patients diagnosed as distal ureteric stone (US) of size <10 mm were included in this study. It was divided into two groups (I and II) out of which 36 cases were excluded. Group I received tablet tamsulosin 0.4 mg/day, and Group II received alfuzosin 10 mg/day. The efficacy of tamsulosin and alfuzosin as an adjunctive medical therapy was determined.

Results:

Both the drugs can be safely used for the distal USs. The stone expulsion rate was seen in 36 patients (72.0%) in Group I, and in 34 patients (68.0%) in Group II (P = 0.545). The passage of stones noticed by 32 patients in each Groups I and II (P = 1.000). The mean number of pain attacks was 2.91 ± 1.01 for Group I, and 1.8 ± 0.83 for Group II (P < 0.001 and P < 0.001). Thus, we propagate the use of alfuzosin significantly lower number of pain attacks. The drug-related side-effects were postural hypertension (four in Group I and one in Group II) and retrograde ejaculation (eight in Group I, and one in Group II). Thus, the difference was statistically significant in terms of retrograde ejaculation but insignificant for postural hypotension.

Conclusion:

There is no difference between both medications in term of efficacy (passing stones) for the management of distal ureteral stones. Both medications are safe and effective. In addition, alfuzosin was better tolerated than tamsulosin as it has fewer side effects.

Pharmacologic Expulsive Treatment of Ureteral Calculi

Objective:

TO evaluate the role of nifedipine and the α1-adrenoreceptor antagonists tamsulosin, terazosin, and doxazosin in the expulsive treatment of ureteral calculi.

Data Sources:

Literature was searched via MEDLINE (1966–February 2006) with subsequent bibliographic review. MeSH headings included ureteral calculi, nifedipine, doxazosin, and adrenergic α-antagonists. Key terms were ureteral calculi, nifedipine, tamsulosin, terazosin, and doxazosin.

Study Selection and Data Extraction:

Trials evaluating nifedipine, tamsulosin, terazosin, and doxazosin for expulsion of ureteral stones were reviewed. All were published in English-language, peer-reviewed journals.

Data Synthesis:

Several trials have evaluated the effects of nifedipine and tamsulosin on ureteral stone passage rates and mean time to stone passage in stones no larger than 15 mm. In 28 day trials, the rates of ureteral stone passage were 35–70% in the control groups compared with 77.1–80% in patients treated with nifedipine and 79.3–100% in patients treated with tamsulosin. Average number of days to stone passage in the control groups was 4.6–20, and the time to stone passage was only 5–9.3 days in patients receiving nifedipine and 2.7–7.9 days in those receiving tamsulosin. The stone passage rates and time to stone passage appeared to be similar in one trial that compared tamsulosin with terazosin and doxazosin. Limited data suggest that these agents may have a role as adjuncts to shock wave lithotripsy. Adverse drug reactions were uncommon.

Conclusions:

Nifedipine, tamsulosin, terazosin, and doxazosin are safe and effective options in enhancing ureteral stone expulsion in selected patients with uncomplicated presentations.

Alpha blockers for treatment of ureteric stones: systematic review and meta-analysis

OBJECTIVE

 To investigate the efficacy and safety of alpha blockers in the treatment of patients with ureteric stones.

DESIGN

 Systematic review and meta-analysis.

DATA SOURCES

 Cochrane Central Register of Controlled Trials, Web of Science, Embase, LILACS, and Medline databases and scientific meeting abstracts to July 2016.

REVIEW METHODS

 Randomized controlled trials of alpha blockers compared with placebo or control for treatment of ureteric stones were eligible. : Two team members independently extracted data from each included study. The primary outcome was the proportion of patients who passed their stone. Secondary outcomes were the time to passage; the number of pain episodes; and the proportions of patients who underwent surgery, required admission to hospital, and experienced an adverse event. Pooled risk ratios and 95% confidence intervals were calculated for the primary outcome with profile likelihood random effects models. Cochrane Collaboration's tool for assessing risk of bias and the GRADE approach were used to evaluate the quality of evidence and summarize conclusions.

RESULTS

 55 randomized controlled trials were included. There was moderate quality evidence that alpha blockers facilitate passage of ureteric stones (risk ratio 1.49, 95% confidence interval 1.39 to 1.61). Based on a priori subgroup analysis, there seemed to be no benefit to treatment with alpha blocker among patients with smaller ureteric stones (1.19, 1.00 to 1.48). Patients with larger stones treated with an alpha blocker, however, had a 57% higher risk of stone passage compared with controls (1.57, 1.17 to 2.27). The effect of alpha blockers was independent of stone location (1.48 (1.05 to 2.10) for upper or middle stones; 1.49 (1.38 to 1.63) for lower stones). Compared with controls, patients who received alpha blockers had significantly shorter times to stone passage (mean difference -3.79 days, -4.45 to -3.14; moderate quality evidence), fewer episodes of pain (-0.74 episodes, -1.28 to -0.21; low quality evidence), lower risks of surgical intervention (risk ratio 0.44, 0.37 to 0.52; moderate quality evidence), and lower risks of admission to hospital (0.37, 0.22 to 0.64; moderate quality evidence). The risk of a serious adverse event was similar between treatment and control groups (1.49, 0.24 to 9.35; low quality evidence).

CONCLUSIONS

 Alpha blockers seem efficacious in the treatment of patients with ureteric stones who are amenable to conservative management. The greatest benefit might be among those with larger stones. These results support current guideline recommendations advocating a role for alpha blockers in patients with ureteric stones.

SYSTEMATIC REVIEW REGISTRATION

 PROSPERO registration No CRD42015024169.

Precise Characterization and 3-Dimensional Reconstruction of the Autonomic Nerve Distribution of the Human Ureter

PURPOSE

We sought to characterize and 3-dimensionally reconstruct the distribution of the autonomic innervation of the human ureter.

MATERIALS AND METHODS

Three male and 3 female pairs of ureters were evaluated at 2 mm serial transverse sections along the entire length of the ureter. The location of nerve tissue was immunohistochemically identified using the neuronal marker, S100 protein. ImageJ software was used to calculate nerve count and density in the adventitia and smooth muscle. Blender® graphics software was used to create a 3-dimensional reconstruction of autonomic nerve distribution.

RESULTS

Within the adventitia nerve density was highest in the mid and distal ureter (females 2.87 and 2.71 nerves per mm², and males 1.68 and 1.69 nerves per mm²) relative to the proximal ureter (females and males 1.94 and 1.22 nerves per mm², respectively, p >0.0005). Females had significantly higher nerve density throughout the adventitia, especially in the distal ureter (2.87 vs 1.68 nerves per mm², p <0.0005). In smooth muscle the nerve density progressively increased from the proximal to the distal ureter (p >0.0005). Smooth muscle nerve density was similar in the 2 genders (p = 0.928). However, in females nerve density was significantly higher in the first 2 cm of the distal ureter relative to the second 2 cm (3.6 vs 1.5 nerves per mm², p <0.001) but not in males (3.0 vs 2.1 nerves per mm², p = 0.126).

CONCLUSIONS

Nerve density was highly concentrated at the distal ureter in the adventitia and smooth muscle of the male and female human ureters. The female ureter had greater nerve density in the adventitia, and in smooth muscle nerves were significantly concentrated at the ureteral orifice and the ureteral tunnel.

Tamsulosin versus tadalafil as a medical expulsive therapy for distal ureteral stones: A prospective randomized study

PURPOSE

This study aimed to compare the safety and efficacy of tamsulosin and tadalafil as medical expulsive therapy for distal ureteral stones.

MATERIALS AND METHODS

This prospective randomized study was conducted at the Department of Urology of Bir Hospital over a period of 12 months in patients with distal ureteral stones sized 5 to 10 mm. Patients were randomly divided into 2 groups: group A received tamsulosin 0.4 mg and group B received tadalafil 10 mg at bedtime for 2 weeks. Stone expulsion rate, number of ureteric colic episodes and pain score, analgesic requirements, and adverse drug effects were noted in both groups. Statistical analyses were performed by using Student t-test and chi-square test.

RESULTS

Altogether 85 patients, 41 in group A and 44 in group B, were enrolled in the study. The patients' average age was 31.72±12.63 years, and the male-to-female ratio was 1.5:1. Demographic profiles, stone size, and baseline investigations were comparable between the 2 groups. The stone expulsion rate was significantly higher in the tadalafil group than in the tamsulosin group (84.1% vs. 61.0%, p=0.017). Although the occurrence of side effects was higher with tadalafil, this difference was not significant (p=0.099). There were no serious adverse effects.

CONCLUSIONS

Tadalafil has a significantly higher stone expulsion rate than tamsulosin when used as a medical expulsive therapy for distal ureteral stones sized 5-10 mm. Both drugs are safe, effective, and well tolerated with minor side effects.

Comparative efficacy of tadalafil versus tamsulosin as the medical expulsive therapy in lower ureteric stone: a prospective randomized trial

Introduction

In recent years, medical expulsive therapy has been used in the management of distal ureteric stones as a supplement to conservative treatment. Therefore, we conducted a prospective randomized study to evaluate the possible role of tadalafil individually in comparison with proven tamsulosin therapy in ureteric stone expulsion.

The aim of this study is to compare the safety and efficacy of a phosphodiesterase-5 inhibitor (tadalafil) and an α-1 blocker (tamsulosin) as medical expulsive therapy for distal ureteric calculi.

Material and methods

Between August 2014 and October 2015, 207 patients who presented with distal ureteric stones of size 5–10 mm were randomly divided into two groups: tadalafil (Group A) and tamsulosin (Group B). Therapy was given for a maximum of 4 weeks. Stone expulsion rate, time to stone expulsion, analgesic use, number of hospital visits for pain, follow-up, endoscopic treatment and adverse effects of drugs were noted. Both groups were compared for normally distributed data by percentage, analysis of variance, and T-test. All the classified and categorical data were analyzed for both groups using the chi-square test.

Results

A statistically significant expulsion rate of 84.0% in Group A compared with 68.0% in Group B (P value = 0.0130), and shorter stone expulsion time in Group A (14.7±3.8) in comparison to Group B (16.8 ±4.5) was observed. Statistically significant differences were noted in renal colic episodes and analgesic requirement in Group A than Group B. No serious adverse effects were noted.

Conclusions

Tadalafil is safe, efficacious, and well tolerated as medical expulsive therapy for distal ureteric stones. This study showed that tadalafil increases ureteric stone expulsion quite significantly along with better control of pain and significantly lower analgesic requirement.

Risks associated with drug treatments for kidney stones

INTRODUCTION

Renal stones are one of the most painful medical conditions patients experience. For many they are also a recurrent problem. Fortunately, there are a number of drug therapies available to treat symptoms as well as prevent future stone formation.

AREAS COVERED

Herein, we review the most common drugs used in the treatment of renal stones, explaining the mechanism of action and potential side effects. Search of the Medline databases and relevant textbooks was conducted to obtain the relevant information. Further details were sourced from drug prescribing manuals. Recent studies of drug effectiveness are included as appropriate.

EXPERT OPINION

Recent controversies include medical expulsive therapy trials and complex role of urinary citrate in stone disease. Future directions in research will involve new medical therapies for stone prevention, for example new drugs for hyperoxaluria.

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.

The Efficacy and Safety of Tamsulosin Combined with Extracorporeal Shockwave Lithotripsy for Urolithiasis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND AND PURPOSE

Many studies have been conducted to investigate adjunctive tamsulosin therapy after extracorporeal shockwave lithotripsy (SWL) for urolithiasis. The results from those studies, however, are still inconsistent. Therefore, we performed a meta-analysis to provide an update on the clinical efficacy and safety of tamsulosin combined with SWL for urolithiasis.

METHODS

A systematic search was performed in PubMed, Cochrane Library, and Embase to identify all relevant randomized controlled trials until January 2015. Two reviewers independently assessed trial quality and extracted data. Meta-analysis was conducted with Review Manager (RevMan), version 5.1.

RESULTS

Twenty-one studies (2093 subjects in total) were identified in the current meta-analysis. Compared with a control group, the experimental group (tamsulosin combined with SWL) showed an increased overall benefit for stone expulsion, with pooled risk ratio (RR) of 1.20 (95% confidence interval [CI], 1.15-1.26). With respect to the different geographic regions, European and American had a high possibility of improvement in stone expulsion (RR: 1.33, 95% CI, 1.19-1.49). According to the stone locations (renal, upper and lower ureteral) and sizes (4-10 mm and 11-24 mm), tamsulosin is more useful for lower ureteral stone (RR: 1.28; 95% CI, 1.14-1.43) and larger sized stones (RR: 1.49; 95% CI, 1.28-1.75). The effect estimates did not vary markedly when stratified by follow-up durations but varied by dose of tamsulosin. Furthermore, a shorter expulsion time, reduced occurrence of steinstrasse, fewer incidences of colic, and lower analgesic requirements were observed within the experimental group. In addition, tamsulosin is well tolerated, and its adverse events rarely led to dropouts of patients.

CONCLUSIONS

Overall, evidence suggests that tamsulosin combined with SWL is safe and effective in enhancing stone expulsion for patients with urolithiasis. Furthermore, high-quality, randomized and placebo-controlled trials evaluating the efficacy and safety of tamsulosin should be performed.

Analysis of factors affecting spontaneous expulsion of ureteral stones that may predict unfavorable outcomes during watchful waiting periods: What is the influence of diabetes mellitus on the ureter?

Purpose

The aim of our study was to evaluate the association of several factors with spontaneous stone expulsion, including ureteral stone characteristics (size, location, hydronephrosis, perinephric stranding), types of medications prescribed (α-blocker, low-dose steroid), and other possible demographic and health-history factors (gender, age, serum creatinine, underlying diabetes mellitus [DM], and hypertension).

Materials and Methods

A total of 366 patients with ureteral stones were enrolled. All patients underwent watchful waiting without any invasive procedures. Initial diagnoses of ureteral stones were confirmed by computed tomography scans, which were taken at approximately 1-month intervals to check for stone expulsion. Univariate and multivariate analyses were conducted to identify significant factors that contributed to stone expulsion.

Results

Among 366 patients, 335 patients (91.5%) experienced spontaneous stone passage during a mean follow-up period of 2.95±2.62 weeks. The patients were divided into two groups depending on the success of spontaneous stone passage. Univariate analyses revealed that stone location (p=0.003), stone size (p=0.021), and underlying DM (p<0.001) were significant predictors of stone passage. Multivariate analyses confirmed that stone size (p=0.010), stone location (p=0.008), and underlying DM (p=0.003) were independent predictive factors affecting stone passage.

Conclusions

Stone size, location, and underlying DM were confirmed to be significant predictive factors for spontaneous passage of ureteral stones. Urologists should consider active procedures, such as shock wave lithotripsy or ureteroscopy, rather than conservative management in patients presenting with proximally located stones, large ureteral stones, or underlying DM.

Long-term prescription of α-blockers decrease the risk of recurrent urolithiasis needed for surgical intervention-a nationwide population-based study

Purpose

α1 receptors and subtypes have been confirmed to distribute in human pelvis and calyces recently. As used in ureteral stones, α-blocker treatment may facilitate kidney stone passage and long-term prescription of α-blocker may decrease the risk of recurrent urolithiasis. The aim of this study is to determine if use of α-blockers 180 days or more can decrease the risk of recurrent urolithiasis needed for surgical intervention.

Materials and Methods

A representative database of 1,000,000 patients from Taiwan’s National Health Insurance was analyzed. Eligible patients were those who had received the first-time procedure for upper urinary stone removal, including extracorporeal shock-wave lithotripsy, ureterorenoscopic lithotripsy, or both, between 2000 and 2010. After completing a 180-day treatment for first event, patients were prospectively followed-up until a second set of stone procedures was performed (proxy of stone recurrence), loss to follow-up, or end of study. The effect of percentage of total number of days of α-blocker use on need for second set of stone procedures within a post treatment 180-day follow-up period was analyzed by quartile. A nested case-control study was also performed.

Results

1,259 patients were eligible for final analyses. During 3,980 person-years follow-up, 167 patients had recurrent urolithiasis needed for surgical intervention. From first to fourth quartile of drug exposure, recurrence rates were 45.64, 47.19, 43.11, and 18.52 per 1,000 person-years. The adjusted hazard ratio was 0.46 (95% CI = 0.24 to 0.89) for the fourth quartile (vs. quartile 1). In the nested case-control study, adjusted ORs was 0.23 (95% CI = 0.10 to 0.53) in the fourth quartile (vs. quartile 1). The results remained similar even in patients categorized by cumulative defined daily dose (cDDD) quartiles and average cDDD per day quartiles.

Conclusion

Use of α-blockers for 180 days or more decrease the risk of recurrent urolithiasis needed for surgical intervention. In patients at higher risk of recurrent urolithiasis, long term prescription of α-blockers might help them prevent further surgical intervention.

Efficacy of nifedipine and alfuzosin in the management of distal ureteric stones: A randomized, controlled study

INTRODUCTION

Stone disease is a significant and world-wide health problem. Recently, certain drugs have been used as a supplement to observation alone in an effort to improve spontaneous stone expulsion. We evaluated the efficacy of nifedipine and alfuzosin in the medical treatment of symptomatic, uncomplicated distal ureteral stones.

MATERIALS AND METHODS

This was a randomized controlled prospective study to determine the efficacy of alfuzosin and nifedipine as an adjunctive medical therapy, to increases the stone-expulsion rates in distal ureteric calculus of size ≤10 mm. Investigators and patients were blinded to the randomization scheme. Patients were randomly divided into three equal groups of 35 patients each. Patients in Group I received tablet nifedipine 30 mg/day, Group II received alfuzosin 10 mg/day and Group III was the control group received tablet diclofenac sodium. The patient blood pressure, stone position on imaging, number of pain attacks, time of stone-expulsion, hospital re-admission and any adverse events were assessed. Patients were followed-up weekly and continued until the patient was rendered stone free or up to 28 days. Statistical analysis was performed and P < 0.05 was considered to be significant.

RESULTS

Stone-expulsion was observed in 60%, 85.7% and 20% patients in Group I, II and III respectively. A statistically significant difference was noted in between Groups I versus III, Groups II versus III and Groups I versus II (P < 0.0001, P < 0.0001, and P < 0.0315 respectively). The mean number of pain attacks was 2.91 ± 1.01 for Group I, 1.8 ± 0.83 for Group II, and 2.82 ± 1.12 for Group III, which is statistical significant in Groups II versus III, and Groups I versus II (P < 0.001 and P < 0.001). Hospital re-admission rate was less in treatment groups when compare to control group (P < 0.0001).

CONCLUSION

The use of alfuzosin and nifedipine as a medical expulsive therapy for distal ureteric stones proved to be safe and effective in term of increased stone-expulsion rate, reduced pain attacks and decrease hospital re-admissions.

Effects by silodosin on the partially obstructed rat ureter in vivo and on human and rat isolated ureters

BACKGROUND AND PURPOSE

α1 -adrenoceptor (-AR) antagonists may facilitate ureter stone passage in humans. We aimed to study effects by the α1 A -AR selective antagonist silodosin (compared to tamsulosin and prazosin) on ureter pressures in a rat model of ureter obstruction, and on contractions of human and rat isolated ureters.

EXPERIMENTAL APPROACH

After ethical approval, ureters of male rats were cannulated beneath the kidney pelvis for in vivo ureteral intraluminal recording of autonomous peristaltic pressure waves. A partial ureter obstruction was applied to the distal ureter. Mean arterial blood pressure (MAP) was recorded. Approximate clinical and triple clinical doses of the α1 -AR antagonists were given intravenously. Effects by the α1 -AR antagonists on isolated human and rat ureters were studied in organ baths.

KEY RESULTS

Intravenous silodosin (0.1-0.3 mg kg(-1) ) or prazosin (0.03-0.1 mg kg(-1) ) reduced obstruction-induced increases in intraluminal ureter pressures by 21-37% or 18-40% respectively. Corresponding effects by tamsulosin (0.01 or 0.03 mg kg(-1) ) were 9-20%. Silodosin, prazosin and tamsulosin reduced MAP by 10-12%, 25-26% (P < 0.05), or 18-25% (P < 0.05) respectively. When effects by the α1 A -AR antagonists on obstruction-induced ureter pressures were expressed as a function of MAP, silodosin had six- to eightfold and 2.5- to eightfold better efficacy than tamsulosin or prazosin respectively. Silodosin effectively reduced contractions of both human and rat isolated ureters.

CONCLUSIONS AND IMPLICATIONS

Silodosin inhibits contractions of the rat and human isolated ureters and has excellent functional selectivity in vivo to relieve pressure-load of the rat obstructed ureter. Silodosin as pharmacological ureter stone expulsive therapy should be clinically further explored.

Silodosin versus Tamsulosin as Medical Expulsive Therapy for Distal Ureteral Stones: A Prospective Randomized Study

Introduction

The aim of this study was to compare the safety and efficacy of silodosin (8 mg) versus tamsulosin (0.4 mg) as a medical expulsive therapy for distal ureteral stones.

Methods

136 patients (aged 18 years or older) had presented with renal colic, were diagnosed to have a single, unilateral, radiopaque, proximal ureteral stone (range 4–10 mm in size), and agreed to undergo conservative management. For a 3-week period, 68 patients per group were assigned to the following treatments: Group A (gA) received tamsulosin 0.4 mg once daily, and Group B (gB) received silodosin 8 mg once daily. The time to expulsion, analgesic use, follow-up, endoscopic treatment and adverse effects of drugs were noted.

Results

Considering all the patients enrolled (136), one patient in gA and two patients in gB were unable to continue the study because of orthostatic hypotension within a week from commencing the treatment. A total of 133 patients (gA: 67; gB: 66) were included in this study. A stone expulsion rate of 61.2% (41 out of 67 patients) was observed in gA, and 80.3% (53 out of 66) was observed in gB. gB showed a statistically relevant advantage in terms of stone expulsion rate (p: 0.003), as well as in terms of expulsion time (weeks) (p: 0.002). No severe complications were recorded in both groups. Four patients (10.2%; 4/39) in gA and ten patients (22.7%; 10/44) in gB experienced retrograde ejaculation (<0.002).

Conclusion

The patients treated with silodosin showed a significant increase in expulsion rate and a decrease in expulsion time of lower ureteral stones in our study.