Allium™ TPS--A New Prostatic Stent for the Treatment of Patients with Benign Prostatic Obstruction: The First Report

Prostatic stents: a narrative review of current evidence

Benign prostatic hyperplasia (BPH) is a common chronic urologic condition affecting approximately 50% of men above the age of 60. As per European Association of Urology Guidelines, BPH can be treated according to a stepwise approach starting from a conservative management, a pharmacologic approach, and finally surgery. Both medical and surgical therapies have side effects, impacting on ejaculation and sexual function and patients with multiple comorbidities might not be considered surgically suitable candidates. Prostatic stents offer a minimally invasive procedures in an out-patient setting, possibly under local anaesthesia. Utilized since the 1980s, the past stents encompassed permanent (epithelializing) or temporary (non-epithelializing) devices, like the Uro-Lume (American Medical Systems, Minnetonka, MN, USA) and the Memokath, or Memotherm (Engineers & Doctors A/S, Denmark), and the biodegradable stents made of self-reinforced poly-L-lactide or braided poly lactic-co-glycolic acid. Previous stents however showed a quite high rate of complications among which pain, incontinence, infections, stent migration or blockage, and incomplete degradation that might lead to premature removal of stent. The stents currently available on the market instead are the temporary device Allium Triangular Prostatic Urethral Stent (Allium Urological Solutions, Caesarea, Israel) and the temporary stent SPANNER (AbbeyMoor Medical, Inc., Parkers Prairie, MN, USA), which might be used in case of bladder outflow obstruction, post-operatively, or for acute urinary retention. Studies showed encouraging results, in terms of effectiveness and safety improving patients' quality of life and International Prostate Symptom Score, but longer-term studies are needed to identify the most suitable patients who might benefit from their use. Newer stents and nitinol devices are currently investigated, and we are waiting for the results of the ongoing clinical trials.

A scoping review of office-based prostatic stents: past, present, and future of true minimally invasive treatment of benign prostatic hyperplasia

PURPOSE

To conduct a scoping review of the existing literature and recent developments on prostatic stents for the treatment of benign prostatic hyperplasia (BPH).

METHODS

A comprehensive search was performed on Embase, MEDLINE, and Web of Science to identify English literature on prostatic stents for the treatment of BPH. Additional studies and upcoming devices were identified through grey literature search and expert consultation. Study characteristics and stent information were extracted and tabulated narratively.

RESULTS

Of the 1171 search results, 64 studies were included in this review. iTiND was the prostatic stent with the most long-term evidence. iTiND is a safe and effective minimally invasive treatment for BPH that preserves sexual function. Adverse events are mild and transitory. Emerging stents (e.g. Zenflow, Butterfly, Urocross, and Exime) had 7/64 eligible studies, where no studies had long-term follow-up. These newer stents show promising results for quality of life and BPH symptom management; however, long-term monitoring and head-to-head comparisons are needed.

CONCLUSION

Over the last 50 years, prostatic stents have evolved and demonstrated improved clinical efficacy. iTiND provides a safe and effective outpatient treatment of LUTS secondary to BPH preserving erectile and ejaculatory function. Emerging prostatic stents are a promising, effective, and safe intervention in well-selected patients interested in its benefits.

Six novel minimally invasive therapies for benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is the most common cause of lower urinary tract symptoms in men. When drug treatment is ineffective or conventional surgery is not suitable, novel minimally invasive therapies can be considered. These include prostatic urethral lift, prostatic artery embolisation, water vapor thermal therapy, Aquablation-image guided robotic waterjet ablation, temporary implantable nitinol device and prostatic stents. These novel therapies can be performed in outpatient setting under local anesthesia, with shorter operative and recovery times, and better protection of ejaculatory function and erectile function. General conditions of the patient and advantages and disadvantages of the each of these therapies should be fully considered to make individualized plans.

Efficacy and tolerability of metallic stent in patients with malignant prostatic obstruction secondary to prostatic cancer

OBJECTIVE

To evaluate the efficacy and tolerability of a self-expandable covered metallic stent in patients with malignant prostatic obstruction secondary to prostate cancer (PC).

METHODS

We reviewed 22 cases of insertion of self-expandable covered metallic stents with barbs. Data were collected about PC status. Uroflowmetry variables, residual urine volume, International Prostate Symptom Score (IPSS), quality of life (QOL), and duration from stent insertion to removal were surveyed. These clinical parameters were compared before and after stent insertion.

RESULTS

The patients with PC showed a mean age of 75.5 ± 6.5 years and mean 5.1 ± 1.9 Charlson comorbidity index. The average flow rate (2.4 ± 1.9 vs 5.9 ± 2.4 mL/s, P = .005), peak flow rate (6.9 ± 6.2 vs 14.1 ± 5.5 mL/s, P = .003), flow time (54.6 ± 29.1 vs 23.6 ± 13.7 s, P = .002), residual urine volume (178.7 ± 195.5 vs 7.0 ± 7.1 mL, P = .004), IPSS (26.2 ± 8.1 vs 8.0 ± 6.5 points, P = .001), and QOL (4.7 ± 1.3 vs 2.4 ± 2.1 points, P = .030) improved between before and after stent insertion, respectively. Pain was the most common complication, but 60% of the patients were managed without any intervention. There were hematuria, urinary retention, urinary frequency, obstruction, and urinary incontinence. However, there was no urinary tract infection due to the stent. The median time to stent removal was 5.7 months.

CONCLUSIONS

The stent was maintained for about 6 months with improved objective and subjective outcomes. The patients with PC, who had a poor comorbidity index and advanced PC status showed a tolerable maintenance period. Self-expandable covered metallic stents can be used for PC patients with a short life expectancy and unsuitability for general anesthesia.

A state-of-art review on the preservation of sexual function among various minimally invasive surgical treatments for benign prostatic hyperplasia: Impact on erectile and ejaculatory domains

There is a strong association between benign prostatic hyperplasia (BPH)/lower urinary tract symptoms (LUTS) and sexual dysfunction. While transurethral resection of the prostate (TURP) is considered the standard BPH treatment, it is however associated with a high rate of erectile and ejaculatory dysfunctions. Over the past decade, new and novel minimally invasive BPH therapies have been shown to improve various parameters of voiding domains while minimizing adverse sexual effects. These minimally invasive BPH therapies can be largely be divided into those with cavitating technology (Rezum, Histotripsy, Aquablation), intra-prostatic injections (Botulinum neurotoxin Type A, Fexapotide Triflutate, prostate specific antigen-activated protoxin PRX-302), and mechanical devices which include intraprostatic stents (Urospinal 2™, Memotherm™, Memokath™, and Allium triangular prostatic stent™) and intraprostatic devices (iTIND™, Urolift™), as well as prostatic artery embolization. Published literature on these technologies showed reasonable preservation of erectile function with limited data reported on ejaculatory domain. Further validation of the performance of these novel minimally invasive treatment options for LUTS due to BPH in well-designed and multi-centre studies are desired, to evaluate their role (or lack of such a role) in clinical practice and whether these BPH therapies can provide equivalent standard or better than TURP.

Beyond medications: office-based procedures for benign prostatic obstruction

PURPOSE

When medications fail to satisfactorily treat bothersome lower urinary tract symptoms (LUTS) due to benign prostatic obstruction (BPO), procedural treatments are indicated. There is much interest in minimally invasive office-based treatments which can be performed under local anesthesia, allow fast recovery and have minimal morbidity. The purpose of this article is to review recent literature regarding safety and efficacy of office-based minimally invasive therapies for BPO.

METHODS

A literature search using PUBMED and Medline was performed regarding minimally invasive office-based treatments for BPO, including the prostatic urethral lift (Urolift), water vapor therapy (Rezum) and stents. Literature published within the last 5 years were reviewed.

RESULTS

The prostatic urethral lift (Urolift) is a safe and efficacious treatment for LUTS-BPO whilst also preserving sexual function. Rezum appears to be a safe and effective treatment in Phase 2 trials. Memokath prostatic stents do not appear to be a durable treatment; Allium prostatic stents warrant further investigation prior to recommendation.

CONCLUSIONS

The prostatic urethral lift (Urolift) is a safe and effective treatment for LUTS-BPO whilst preserving sexual function. Rezum also appears to be a safe and effective treatment in small RCTs comparing performance with TURP. Memokath prostatic stents do not appear to have treatment durability. Further studies would be warranted to determine whether Allium prostatic stents are safe effective treatments for LUTS-BPO.

Allium Stents: A Novel Solution for the Management of Upper and Lower Urinary Tract Strictures

Stents are widely use in endoscopic urological procedures. One of the most important indications is the treatment of urinary tract strictures. Allium™ Medical has introduced several types of stents for the treatment of different types of urinary tract strictures, based on anatomic location. All the stents are made of nitinol and coated with a co-polymer that reduces encrustations. These stents are self-expandable and have a large caliber and a high radial force. They have different shapes, designed especially for the treatment of each type of stricture. One of the most important features of Allium-manufactured stents is the ease of removal, due to their special unraveling feature. The company has introduced the Bulbar Urethral Stent (BUS) for treatment of bulbar urethral strictures; a rounded stent available in different lengths. Initial data on 64 patients with bulbar urethral stricture treated with the BUS showed a significant improvement in symptoms, with minimal complications and few adverse events. For treatment of prostate obstruction in patients unfit for surgery or unwilling to undergo a classical prostatic surgery, the Triangular Prostatic Stent (TPS) was introduced, which has a triangular shape that fits in the prostatic urethra. Its body has a high radial force attached to an anchor (which prevents migration) through a trans-sphincteric wire (which reduces incontinence rate). Initial data on 51 patients showed significant improvement in symptoms and in urinary peak flow rate, with a relatively small number of complications. The Round Posterior Stent (RPS) was designed for treatment of post radical prostatectomy bladder neck contracture. This short, round stent has an anchor, which is placed in the bladder neck. This stent being relatively new, the clinical data are still limited. Ureteral strictures can be treated with the Ureteral Stent (URS), which is round-shaped, available in different lengths, and has an anchor option (for very distal or very proximal strictures). We have previously published data on 107 URSs inserted in patients with ureteral stricture due to several etiologies, including patients who failed previous treatment. All patients were asymptomatic for a long period of follow-up after stent removal, with only one case of re-stenosis. In this paper, we review the urological "covered" stents produced by Allium Medical with the relevant clinical data available at the present time.

Minimally invasive surgical therapies for benign prostatic hypertrophy: The rise in minimally invasive surgical therapies

The prevalence of benign prostatic hypertrophy (BPH) causing bothersome lower urinary tract symptoms increases with our ageing population. Treatment of BPH traditionally begins with medical therapy and surgical intervention is then considered for those whose symptoms progress despite treatment. Minimally invasive surgical therapies have been developed as an intermediary in the treatment of BPH with the aim of decreasing the invasiveness of interventions. These therapies also aim to reduce morbidity and dysfunction related to invasive surgical procedures. Multiple treatment options exist in this group including mechanical and thermo-ablative strategies. Emerging therapies utilizing differing technologies range from the established to the experimental. We review the current literature related to these minimally invasive therapies and the evidence of their effectiveness in treating BPH. The role of minimally invasive surgical therapies in the treatment of BPH is still yet to be strongly defined. Given the experimental nature of many of the modalities, further study is required prior to their recommendation as alternatives to invasive surgical therapy. More mature evidence is required for the analysis of durability of effect of these therapies to make robust conclusions of their effectiveness.

Guidelines of guidelines: a review of urethral stricture evaluation, management, and follow-up

BACKGROUND

Our objective is to report a comparative review of recently released guidelines for the evaluation, management, and follow-up of urethral stricture disease.

METHODS

This is an analysis of the American Urologic Association (AUA) and Société Internationale d'Urologie (SIU) guidelines on urethral stricture. Strength of recommendations is stratified according to letter grade that corresponds to the level of evidence provided by the literature.

RESULTS

Although few, the discrepancies between the recommendations offered by the two guidelines can be best explained by varying interpretations of the literature and available evidence on urethral strictures. When comparing the AUA guidelines and the SIU guidelines on urethral stricture, there are very few discrepancies. Perhaps the most notable difference is in the use of repeat DVIU or urethral dilation after an initial failed attempt. SIU guidelines state that there are instances where repeat DVIU or urethral dilation can be indicated, and they give a range of time at which stricture recurrence post procedure mandates an urethroplasty (less than 3 to 6 months). The AUA guidelines definitively state that repeat endoscopic procedures should not be offered as an alternative to urethroplasty, and they do not mention time of stricture recurrence as a factor. SIU guidelines allow for management of urethral stricture with indwelling urethral stenting.

CONCLUSIONS

Overall there is a need for more high quality research in the work up, management, and follow up care of urethral stricture.