Treatment of Post, High-Intensity-Focused Ultrasound Urethral Stricture with Novel Long-term Stent

ABSTRACT

Urethral strictures (US) can be recurrent chronic illnesses leading to severe side effects and poor quality of life. Several options to treat US exist, including repeated dilatations, stents, and open surgery. A urethral stent is a good, minimally invasive option but has major limitations, such as stent migration, mucosal growth, and incontinence, especially for bladder-neck strictures. Herein, we describe a new stent that, due to its design, may solve some of the above-mentioned problems, enabling long-term use and safe removal.

CASE REPORT

A 66-year-old presented to us who, three years earlier, had undergone high-intensity-focused ultrasound (HIFU) treatment for organ-confined (Gleason score 3+4) prostate cancer. Approximately 3 months after the procedure, he presented to his local urologist with progressive-obstructive voiding symptoms that were managed endoscopically via visual internal urethrotomy, followed by a transurethral resection of stenotic scar tissue. Afterwards, he underwent repeated endoscopic treatment for restenosis every 10 to 12 weeks. A typical pre-and post-treatment endoscopic view is shown in Figure 1. Upon arrival at our medical center, the patient underwent a rinary ultrasound that revealed a normal upper urinary tract, small prostate, and 240 ml of post-void residual urinary volume. Uroflowmetry demonstrated an obstructive pattern with maximal urinary flow of 5.6 ml/sec. A cystoscopy demonstrated a tiny opening of the urethra at the level of the prostatic urethra/bladder-neck area. The patient was referred for an Allium round posterior urethral stent (RPS) placement.

Description of the Allium RPS Stent

The Allium RPS system is indicated for the management of bladder outlet obstruction in adult males. The stent, presented in Figure 2 and Figure 3, is a large-caliber, long-term, fully covered stent made of a self-expandable Nitinol skeleton covered with a thin membrane of biocompatible and biostable copolymer. The entire skeleton of the RPS is made of a single Nitinol wire. The copolymer covers the entire stent body and its anchor to prevent intraluminal tissue ingrowth. It has a single length of 40 mm, a 45 Fr round cross-section, and is composed of 3 segments: body (40 mm), anchor (14 mm), and transsphincteric wire, which connects the body to the anchor.