Injection Therapy to Treat Stress Incontinence
Injecting material to increase the bulk around the urethra can improve the function of the urethral sphincter and compresses the urethra near the bladder outlet.
Injectable agents can help women who are not candidates for surgery and have persistent intrinsic sphincter deficiency (very weak urethral sphincter) without urethral hypermobility. Injectable agents also may help men with intrinsic sphincter deficiency that has lasted longer than 1 year.
Injectable materials include collagen (naturally occurring protein found in skin, bone, and connective tissue), fat from the patient's body (autologous fat), and polytetrafluoroethylene (PTFE) and Durasphere® (synthetic compounds).
Collagen is a natural substance that breaks down and is excreted over time. The Contigen Bard collagen implant uses a purified form of collagen derived from cowhide. Potential recipients have a skin test 28 days prior to treatment to determine whether or not they are sensitive to the material.
Sensitivity is indicated by inflammation at the injection site.
A prefilled syringe is used to inject the collagen around the urethra. Some physicians conduct a series of treatments over a few weeks or months. Others instruct patients to return for additional treatment when leakage occurs. Results vary from patient to patient and from physician to physician. Some patients achieve continence for 12 to 18 months and others require more frequent treatment. Some remain dry for 3 to 5 years.
Autologous fat injections are used to treat intrinsic sphincter deficiency. Fat from the patient's body is gathered by liposuction from the abdominal wall and is injected around the urethra in a simple procedure performed under local anesthesia. Long-term effectiveness of this procedure is not known.
This synthetic compound in the form of a micropolymer paste is injected into the upper urethra. The PTFE particles spur the growth of fibroblasts (fiber-making cells), which fix the material in the urethral tissue and assist in urethral closure. PTFE is not an approved treatment for incontinence in the United States because PTFE particles may migrate to other parts of the body, such as the lungs, brain, and lymph nodes.
Durasphere is a water-based gel that contains tiny, carbon-coated beads. Unlike PTFE, this material is not absorbed by the body. The procedure is usually performed under local anesthesia, although some patients may require general anesthesia. A cystoscope is inserted into the urethra, allowing the physician to see the bladder neck area. The gel is injected through a hollow needle into the numbed areas of tissue around the bladder neck. This increases the bulk around the urethral sphincter, allowing it to close enough to help prevent urine from leaking. After treatment, 9 out of 10 women experience improved continence.