Urethral stents are plastic, metal or biodegradable mesh tubes placed in the urethra to correct an obstruction in the flow of urine from the bladder. The placement of a stent in the urethra, whether anterior or prostatic, depends on the circumstances of individual cases and the type of stent considered. However, certain indications are accepted for urethral stent placement as outlined in 2007 and 2010 expert recommendations.
Indications for Urethral Stent Placement
Stent placement is often pursued when surgical options have been ruled out or previously unsuccessful. Patients with an enlarged prostate gland (benign prostatic hyperplasia, or BPH) are generally not surgical candidates because the prostate gland can be reduced with pharmacological treatment. A temporary stent in the prostate urethra can reduce urine blockage until treatment has been successful. Some patients with an obstructed urethra may also not benefit from stents because of other medical complications that make them ineligible for anesthesia use.
Urethral strictures are obstructions of the duct by scar tissue, which may be corrected by surgery, though permanent stents have been found to be a less invasive and viable alternative that reduce further scarring and obstruction compared to urethroplasty (reconstruction of the urethra) for small strictures. Stents also have a better success rate for treating stricture than urethreotomy (incision of the urethra with subsequent dilation) based on expert testimony. Temporary stents could also be used for relief until a patient can undergo surgery.
Contraindications for Urethral Stent Placement
The contraindications for stent placement in the urethra are considered to include the following: inability to dilate the urethral lumen to the necessary diameter, stricture larger than 6 cm, meatal stricture (which is often caused by infection or congenital skin disorder), stricture extending past the bulbar-scrotal junction in men (penile stricture), young age (generally considered in this context to be 21 years and under), and coexisting disease that can affect placement, including prostate cancer, recurrent bladder tumors, urinary tract infection, kidney stones and inflammatory disorders (e.g., prostatitis.)
Previous stent failure, in terms of stenosis after use to correct strictures, is usually not an indicator of future stent failure, according to a 2007 study in the Journal of Urology. The overall success rate after treatment for failed stenting in 22 patients was 67 percent for posterior strictures (toward the prostate and bladder) and 82 percent for anterior strictures. If necessary, urethral stents can be removed by endoscopy and the more invasive urethroplasty pursued.
Amukele, Thakre and Badlani. Urethral Stents. Smith’s Textbook of Endourology, 2nd edition, 2007.
Duvdevani, Chew and Denstedt. Urethral stents: Review of technology and clinical applications. 2010.