Temporary urethral stent with perineal fixation for posterior urethral stenosis (preliminary results)

Introduction. Urethroplasty is the “gold standard” treatment of urethral stenosis. However, often in connection with old and senile age, as well as due to the presence of concomitant diseases, it is not possible to carry out urethroplasty due to its certain invasiveness. In such cases, one of the methods of treatment is the installation of a urethral stent. But this method has not found practical application due to the frequent migration of stent and the high frequency of its incrustation. The approach developed by us avoids stent migration.Purpose of the study. To evaluate the immediate results of the placement of a urethral stent with fixation through the perineum.Materials and methods. A total of 18 patients with urethral stenosis aged 68 to 84 years have been operated on since February 2019. Ten patients had stenosis of the urethrocystoneoanastomosis after radical prostatectomy, 6 patients had iatrogenic stenosis of the prostatic urethra, 1 patient had post-radiation stenosis of the bulbo-membranous urethra. All patients in the preoperative and postoperative periods underwent: IPSS-QoL questioning, uroflowmetry, bladder ultrasound with residual urine volume evaluation, urethroscopy, ascending and micturition urethrocystography. The first stage was an internal optical urethrotomy according to the standard technique. Then, a urethral stent was installed in the area of dissected stenosis. The second stage was an incision in the perineum, the urethra was isolated, and under optical control, through the perineum, the stent was fixed to the urethra with non-absorbable suture material. The stent was removed endoscopically after 6 months.Results. The median surgery duration averaged 45 minutes. Patients were discharged 2 to 3 days after surgery. The maximum observation period was 20 months. During the observation period, not a single case of stent migration was recorded. All patients showed a persistent increase in Qmax and no residual urine. Six patients had a stress component of urinary incontinence, 4 patients had total urinary incontinence. According to control urethrocystoscopy 6 months after stent removal, clinically insignificant urethral stenosis was noted in all patients. In all cases, moderate signs of stent encrustation were identified. Dysuric phenomena disturbed 5 patients, who were stopped by rectal suppositories with NSAIDs, as well as taking herbal uroseptics. The data from the IPPS-QoL questionnaires confirm the positive effect of the treatment.Conclusions. Temporary placement of a urethral stent for urethral stenosis is an effective minimally invasive treatment. The technique of fixation through the perineum allows preventing migration in all cases. This approach to treatment significantly improves the quality of life of patients who were contraindicated for urethroplasty for one reason or another. However, the technique requires longer observation and analysis.

Material properties of urethral stents for hypospadias repair

Introduction: Despite the prevalence of hypospadias surgery and the near ubiquitous use of postoperative urethral stents, there has been no evaluation of the material properties of commonly used choices. Our study sets out to close this gap with an evaluation and comparison of the material properties of four urethral stents commonly used after hypospadias surgery. Study Design: Thermal analysis and mechanical analysis of the Zaontz Urethral Stent, the Firlit-Kluge Urethral Stent, the Koyle Diaper Stent, and the Bard Premature Infant Feeding Tube were performed. Results: Thermal analysis shows that all four compositions tested are rubbery polymers at body temperature, with glass transition temperatures far below human body temperatures. The Zaontz and Koyle stents are thermoplastic elastomers with strong melting transitions above body temperature, but the Firlit-Kluge stent is completely amorphous at body temperature and is likely chemically cross-linked to generate the polymer network. The Bard feeding tube was by far the stiffest, with a Young's Modulus of 14.0±0.78 (compared to the Zaontz stent at 4.12±0.56, the Firlit-Kluge stent at 4.92±0.63, and the Koyle stent at 4.09±0.49.) The Firlit-Kluge stent was the strongest, with 84.3±2.83 MPa required to fracture it compared to the Zaontz stent at 65.5±2.57, the Koyle stent at 66.8±3.16, and then Bard feeding tube at 34.6±1.89. Discussion: While there is little information associating urethral stent type with outcomes after hypospadias surgery, material properties may account for findings of prior studies. Stiffer stents may contribute to decreased postoperative comfort, while a stent that is too soft and extensible may have issues with dislodgement, kinking and breaking. Conclusion: This study provides a foundation for future work optimizing urethral stents, designing support for regenerative medicine applications, and improving hypospadias outcomes.

A New Technique for Computed-Tomography Urethrography in Males: The Clamp Method

The aim of the present study is to describe and evaluate a new technique for performing Computed-Tomography Retrograde Urethrography (CT-RUG). Males with urethral anomalies detected by retrograde urethrography (RUG) and/or retrograde sonourethrography (RSUG) underwent CT-RUG using the clamp method and three radiologists evaluated the anomalies in each technique separately and blindly. CT-RUG was done successfully in all the cases (n = 22), with means of 6 min duration and 95 mL of contrast; no pain was reported by 81% of the patients (VAS: 0) and very mild pain by the rest (VAS: 0.5–1.2). CT-RUG showed better diagnostic efficacy in cases of periurethral fistula (n = 8), urethral stent (n = 3), previous urethroplasty and urethral lithiasis (n = 2), a similar accuracy to RSUG for measuring the length of anterior urethral strictures (n = 9) and greater accuracy than RUG (p = 0.008). Six cases received 2 CT sweeps, with an effective dose of 4.96 mSv, and the remaining 16 had 1 sweep and received 3.456 mSv. To the best of our knowledge, this is the first study to describe the clamp method for CT-RUG, a method that is effective and comfortable for both the patient and the operator (retrograde infusion of contrast).

Biodegradable drug-eluting urethral stent in limiting urethral stricture formation after urethral injury: An experimental study in rabbit

In this study, a reproducible urethral injury animal model was developed and the role of the biodegradable drug-eluting urethral stent in limiting urethral stricture formation after urethral injury was evaluated. A total of 22 rabbits were used, and 20 rabbits were randomly chosen to develop urethral injury animal model. Bulbar urethral injury was made by a self-designed explosion device in the 20 rabbits. The urethral injury animal model was then randomly assigned to 2 groups of 10 each, which received a treatment of biodegradable paclitaxel-eluting urethral stent or only end-to-end anastomosis. Other two rabbits served as normal control group. Stents were surgically implanted into the injured urethras of rabbits under direct vision. Reparative effects, including stent degradation, were evaluated by urethroscopy, retrograde urethrography, and histology at different intervals at weeks 4, 8, and 12. In stent-free group, 8 of 10 rabbits developed obvious urethral stricture which was demonstrated by urethroscopy and retrograde urethrography, while in biodegradable paclitaxel-eluting stent group, urethral stricture was absent in all animals (p < 0.05). Histological follow-up indicated that the drug-eluting stents can also minimize the inflammatory reactions and fibrosis formation compared with the stent-free groups. Scanning electron microscope demonstrated that the biodegradable drug-eluting stent can gradually degrade in 12 weeks. The biodegradable paclitaxel-eluting urethral stent is effective in limiting urethral stricture formation after urethral injury.

Novel Treatment Strategy for Management of Traumatic Bulbar Urethral Rupture Using Temporary Urethral Stent after Primary Realignment; Retrospective Comparison between Thermo-Expandable Urethral Stent and Self-Expandable Polymer-Coated Urethral Stent

A variety of retrievable and other types of temporarily placed stents are currently being used. However, only a few studies have considered primary endoscopic realignment with temporary urethral stent insertion in the event of traumatic bulbar urethral injury. We aimed to compare the clinical effectiveness and complications between thermo-expandable urethral stents and polymer-coated bulbar urethral stents (BUSs) for the treatment of traumatic bulbar urethral strictures. Between September 2011 and March 2018, 30 patients who had been diagnosed with complete bulbar urethral rupture following blunt trauma underwent temporary urethral stent placement after primary realignment. Thermo-expandable nickel-titanium alloy urethral stents were placed for 15 patients (group M), and retrievable self-expandable polymer-coated BUSs were placed for another 15 patients (group A). All stents were removed within 6 months after placement. The complications and maintained patency rates were compared between the two groups. The mean stent indwelling period was 5.0 ± 2.5 months in group M and 4.9 ± 4.0 months in group A. Both groups maintained high patency rates (Group M 12/15 (80.0%) and group A 13/15 (86.7%)). Five patients who developed urethral stricture underwent direct visual internal urethrotomy (DVIU), and no patients required repeat DVIU or open surgical urethroplasty. Both groups maintained the mean maximal urinary flow rate (Qmax) at 12 months after stent removal. Discomfort (46.7% vs. 6.7%), granulation tissue formation (73.3% vs. 26.7%) and post-void dribbling (80.0% vs. 20.0%) were more frequent in group M than in group A (p = 0.013, p = 0.011 and p = 0.001, respectively). In conclusion, both stents were effective for managing traumatic complete bulbar urethral rupture after primary realignment. However, the thermo-expandable urethral stents had a higher complication rate while the stent was in situ than the BUSs.