Introduction

In the intervening 70 years since its first description, various materials have been used as agents in urethral injection therapy (UIT) for the treatment of urinary incontinence. The peak interest in UIT occurred in the mid-1990s to the early 2000s; presumably because of mediocre clinical results, especially long term, and the increase in popularity of alternative treatment options, the initial enthusiasm has waned. However, UIT still has a role in treatment of stress urinary incontinence (SUI) because it is minimally invasive, well tolerated, and beneficial, especially in the short-term. It can be easily administered in the outpatient setting with very little associated morbidity. Appropriate patient selection is paramount because in the right patient, urethral injection bulking therapy can play an important role in treating SUI.

History

UIT for urinary incontinence was first reported in the 1930s and included materials such as sodium morrhuate, paraffin wax, and other sclerosing agents. The technique gained greater widespread acceptance with the use of polytetrafluoroethylene (Teflon) in the 1970s and 1980s along with concomitant development of the concept of intrinsic sphincter deficiency (ISD), a characterization of SUI without urethral hypermobility. Additional agents that emerged at that time included autologous fat and collagen. Eventually polytetrafluoroethylene and fat were abandoned because of safety concerns; however, collagen would become and remained until recently the gold standard agent for injection therapy. In the last 2 decades, numerous synthetic and biologic agents have entered the market, some with encouraging results and others with significant safety issues (e.g., Tegress™). Finally, with the advent of efficacious, minimally invasive midurethral slings (see Chapters 6–8), popularity and perceived need for UIT for ISD have waned.

Patient Selection

Traditionally, UIT has been reserved for patients specifically with isolated ISD (i.e., urodynamically proven low abdominal leakpoint pressure [<100 cm H₂O], limited urethral mobility, and absence of detrusor instability). With greater experience using UIT, a broader range of patients with SUI have been treated, and the technology can be applied to all types of SUI.

Good candidates for UIT generally include patients who:

1. Are poor surgical candidates

2. Are elderly and at greatest risk of retention after a sling procedure

3. Must continue anticoagulation therapy at all times

4. Desire nonsurgical therapy using only local anesthesia

5. Are unable to follow postoperative activity limitations required after anti-incontinence procedures

6. Desire more children in the future

7. Have SUI and poor bladder emptying

8. Have had suboptimal symptom improvement after sling surgery (i.e., possible salvage procedure)

An important role for UIT may be as an adjuvant treatment option after an incomplete response to more definitive treatment. Durable responses are possible in patients with persistent SUI after a failed incontinence procedure or pelvic organ prolapse surgery who were treated with collagen injection. Additionally, UIT may be considered as a “first-line” therapy, with more definitive intervention reserved (e.g., midurethral sling) for patients who fail UIT. Efficacy of subsequent incontinence procedures does not seem to be affected by previous UIT.

Finally, managing patient expectations is very important. Most women have expectations that their urine leakage will be eliminated by a single anti-incontinence surgical procedure. However, patients need to understand that UIT should be viewed as a process, rather than a single intervention, and multiple injections may be required to achieve satisfactory results.