Ureteral Stents: Indications and Management in Urological Practice

Ureteral Stents: Indications and Management in Urological Practice

Ureteral stents are indispensable tools in contemporary urological practice, serving a critical role in maintaining urinary tract patency and facilitating various urological procedures. These devices are typically placed with cystoscopic guidance in an operating room setting to ensure proper positioning and minimize complications [1]. The primary objective of a ureteral stent is to allow the unobstructed passage of urine from the kidney to the bladder, thereby preventing or alleviating complications associated with urinary tract obstruction [2, 3]. While highly beneficial, ureteral stent placement is often associated with some degree of patient morbidity, ranging from generalized urinary discomfort to more severe issues such as infection or obstruction [1]. This academic blog post will delve into the key indications for ureteral stent placement and the essential aspects of their management within urological practice, without providing medical advice.

Indications for Ureteral Stent Placement

The decision to place a ureteral stent is driven by several clinical scenarios, primarily centered on reestablishing or maintaining the patency of the ureter. Ureteral stents passively dilate the ureter, allowing urine to flow both through the central lumen and around the stent, which aids in the passage of debris [1, 2]. Key indications include:

• **Ureteral Obstruction:** This is the most common indication, often caused by nephrolithiasis (kidney stones), tumors, or retroperitoneal fibrosis. Obstruction can be uncomplicated or complicated by urinary tract infection, renal insufficiency, or renal failure. Patients with complicated obstruction require prompt decompression of the urinary tract, typically achieved with an indwelling ureteral stent or a percutaneous nephrostomy tube [1, 6]. Ureteral stents are generally preferred due to their less invasive nature and lower risk of bleeding compared to percutaneous nephrostomy [1].
• **Ureteral Anastomosis:** Stents are used to promote ureteral healing following surgical rejoining of the ureter, ensuring proper drainage during the healing process [1].
• **Prophylactic Placement:** Stents may be placed prophylactically to assist with ureteral identification during complex pelvic surgeries, thereby reducing the risk of iatrogenic injury [1]. They are also used to facilitate the passage of stone fragments after treatment and to prevent ureteral obstruction or delayed stricture formation [2]. In emergency situations, stents can drain obstructed and infected kidneys [2].

Management of Ureteral Stents

Effective management of ureteral stents is crucial to optimize patient outcomes and minimize complications. This involves careful consideration of stent design, material, and patient care protocols [1, 2].

Stent Design and Materials

The ideal ureteral stent would possess characteristics such as easy insertion and removal, resistance to encrustation and migration, biocompatibility, radio-opacity, and optimal flow characteristics [2]. Stents are made from various materials, each with distinct properties:

• **Polyurethane (PU):** Biocompatible with good mechanical properties, but prone to encrustation [2, 6].
• **Silicone:** Inert, non-toxic, flexible, and softer, with a lower encrustation rate, making it suitable for stone disease after ureteroscopy [2, 7].
• **Copolymers:** Developed to overcome the disadvantages of other polymers, aiming for better biocompatibility and tolerance [2].
• **Metallic Stents:** Useful for long-term drainage and resistant to high compression forces, with some designed to remain in place for 1-3 years. They offer less morbidity and a greater patency rate compared to double J stents in certain situations [2, 8, 9].
• **Biodegradable Stents:** May reduce morbidity and eliminate the need for removal, though degradation can lead to fragments that favor bacterial adhesion and encrustation [2, 10, 11, 12].

Stent coatings are also being developed to reduce complications, including lubricating, antimicrobial, anti-fouling, and drug-eluting types [2].

Routine Patient Care and Complications

Patients with ureteral stents often experience irritative symptoms and pain, which require appropriate management [1]. Common complications associated with ureteral stents include:

• **Stent-Related Symptoms (SRS):** These can include flank pain, bladder irritation, and hematuria. The incidence of SRS is influenced by stent composition, with softer stents potentially reducing symptoms [2, 5].
• **Encrustation:** The formation of mineral deposits on the stent, which can lead to obstruction and difficulty in removal [1, 2].
• **Urinary Tract Infection (UTI):** Stents can provide a surface for bacterial colonization, increasing the risk of UTIs [1, 2].
• **Migration:** Displacement of the stent from its intended position [1, 2].
• **Retained Stent:** A stent that is not removed in a timely manner, leading to increased complications [1].

Patient counseling regarding potential symptoms and proper care is essential. Stent exchange or removal is performed based on the clinical situation and stent type [1].

Conclusion

Ureteral stents are vital instruments in urological surgery, frequently employed to manage urinary obstruction and facilitate various procedures. A thorough understanding of their indications, diverse designs, materials, and potential complications is paramount for urologists to select the most appropriate stent and provide optimal patient care. Ongoing research continues to explore novel materials and designs to enhance stent tolerability and reduce associated morbidities, ultimately improving patient quality of life [2].

References

[1] Nakada, S. Y., & Patel, S. (2024). *Placement and management of indwelling ureteral stents*. UpToDate. Retrieved from https://www.uptodate.com/contents/placement-and-management-of-indwelling-ureteral-stents [2] Bernasconi, V., Tozzi, M., Pietropaolo, A., De Coninck, V., Somani, B. K., Tailly, T., ... & Talso, M. (2023). *Comprehensive overview of ureteral stents based on clinical aspects, material and design*. Central European Journal of Urology, 76(1), 49–56. https://pmc.ncbi.nlm.nih.gov/articles/PMC10091895/ [3] Mosayyebi, A., Vijayakumar, A., Yue, Q. Y., & Somani, B. K. (2017). *Engineering solutions to ureteral stents: Material, coating and design*. Central European Journal of Urology, 70(3), 270-274. https://pmc.ncbi.nlm.nih.gov/articles/PMC5687284/ [4] Lee, L. (2009). *Urinary Stone Diseases: The Practical Guide to Medical and Surgical Management*. Annals of the Royal College of Surgeons of England, 91(5), 448. (Cited in [2]) [5] Boeykens, M., Keller, E. X., Bosio, A., & Somani, B. K. (2022). *Impact of Ureteral Stent Material on Stent-related Symptoms: A Systematic Review of the Literature*. European Urology Open Science, 45, 108-117. (Cited in [2]) [6] Thomas, A., Cloutier, J., Villa, L., Letendre, J., Ploumidis, A., & Traxer, O. (2017). *Prospective Analysis of a Complete Retrograde Ureteroscopic Technique with Holmium Laser Stent Cutting for Management of Encrusted Ureteral Stents*. Journal of Endourology, 31(5), 476-481. (Cited in [2]) [7] Wiseman, O., Ventimiglia, E., Doizi, S., & Somani, B. K. (2020). *Effects of Silicone Hydrocoated Double Loop Ureteral Stent on Symptoms and Quality of Life in Patients Undergoing Flexible Ureteroscopy for Kidney Stone: A Randomized Multicenter Clinical Study*. Journal of Urology, 204(4), 769-777. (Cited in [2]) [8] Gu, A., Oyo, L., Grossmann, N. C., & Somani, B. K. (2022). *Tumor Stent for Chronic Ureteral Obstruction: Which Are Predictors of Stent Failure?*. Journal of Endourology, 36(7), 819-826. (Cited in [2]) [9] Sampogna, G., Grasso, A., & Montanari, E. (2018). *Expandable metallic ureteral stent: indications and results*. Minerva Urologica e Nefrologica, 70(3), 275-285. (Cited in [2]) [10] Forbes, C., Scotland, K. B., Lange, D., & Chew, B. H. (2019). *Innovations in Ureteral Stent Technology*. Urologic Clinics of North America, 46(2), 245-255. (Cited in [2]) [11] Yang, G., Xie, H., Huang, Y., & Somani, B. K. (2017). *Immersed multilayer biodegradable ureteral stent with reformed biodegradation: An in vitro experiment*. Journal of Biomaterials Applications, 31(10), 1235-1244. (Cited in [2]) [12] Barros, A. A., Oliveira, C., Ribeiro, A. J., & Somani, B. K. (2018). *In vivo assessment of a novel biodegradable ureteral stent*. World Journal of Urology, 36(2), 277-283. (Cited in [2])