A transurethral bulking agent is a substance injected into the tissues surrounding the urethra, the tube that carries urine from the bladder out of the body. This minimally invasive, non-surgical treatment aims to enhance urinary control for individuals experiencing involuntary urine leakage. The procedure adds volume to the urethral walls, improving the natural closing mechanism.
Mechanism of Action
Transurethral bulking agents work by increasing the bulk of the urethral walls, narrowing the urethra’s diameter. The injected material creates a “cushioning” effect, increasing outlet resistance and promoting a watertight seal. This increased resistance helps the urethra to coapt, or close more effectively, both at rest and during activities that increase abdominal pressure.
A variety of materials can be used as bulking agents, including synthetic polymers like polyacrylamide hydrogel (Bulkamid) and silicone microparticles (Macroplastique). Durasphere, consisting of pyrolytic carbon-coated graphite beads suspended in a water-based gel, is another example. These substances remain in place, supporting the urethra and improving its functional length.
Conditions Addressed
Transurethral bulking agents are primarily used to treat stress urinary incontinence (SUI). SUI is characterized by the involuntary leakage of urine during physical activities that exert pressure on the bladder, such as coughing, sneezing, laughing, exercising, or lifting. This condition often arises from weakness in the pelvic floor muscles or the urethral sphincter.
The treatment is often considered for mild to moderate forms of SUI, particularly when conservative treatments like pelvic floor exercises have not been successful. It also serves as an option for patients who prefer to avoid more invasive surgical procedures or who may not be suitable candidates for major surgery due to other health conditions. While it is a treatment option for women with SUI, it is not as effective for men.
The Procedure and Recovery
The transurethral bulking agent procedure typically takes about 10 to 15 minutes. It can be performed in an outpatient setting, such as a doctor’s office or an outpatient surgical center, and may involve local anesthesia, intravenous (IV) sedation, or general anesthesia. A cystoscope, a thin scope with a camera, is inserted into the urethra to visualize the area.
Using the cystoscope as a guide, a small needle is introduced through a channel in the scope and inserted into the mid-portion of the urethra. The bulking agent is then injected into the urethral wall at several sites, typically three or four, to achieve the desired bulking effect. Patients can usually go home the same day after the anesthesia wears off and they are able to urinate on their own.
Following the procedure, patients may experience mild discomfort, a burning sensation when urinating, or a small amount of blood in their urine, which usually resolves within a day or two. Most individuals can resume normal activities within 24 to 48 hours, though strenuous activities and heavy lifting should be avoided for about two weeks to allow the area to heal. It is also advisable to avoid hot baths for a few days, as soaking in hot water might affect the bulking agent’s effectiveness.
Expected Outcomes and Considerations
The effectiveness of transurethral bulking agents can vary, with success rates for significant improvement or complete dryness typically ranging from 50% to 70%. However, the effects may not be permanent, and some women may experience a return of symptoms over time, often requiring repeat injections.
Potential side effects, though generally mild and transient, can include temporary burning with urination, urinary urgency, or temporary difficulty emptying the bladder. More serious complications, such as the formation of an abscess at the injection site due to infection, or migration of the bulking agent, are uncommon. Allergic reactions to the bulking agent are also rare.
While the procedure generally has a good safety profile, it is important for patients to discuss the potential for repeat procedures and the factors that may influence long-term success with their healthcare provider.