Stress urinary incontinence (SUI) is a well-documented complication among men who have prostatic surgery, particularly following radical prostatectomy for cancer. Postprostatectomy SUI (PPSUI) affects 8–25% of patients, and some studies suggest that the true prevalence is underestimated [1], [2]. Regardless, PPSUI significantly reduces patients’ quality of life [2].

Although pelvic-floor physiotherapy is the first-line approach for PPSUI, primary treatment options also include an artificial urinary sphincter and male suburethral mesh sling. However, there are growing safety concerns regarding mesh slings in women who have SUI in terms of the risk of “life-changing injuries” [3]. Similar concerns have been raised for men who have PPSUI, prompting interest in less invasive alternatives.

There has been an increase in interest in bulking agents as a less invasive alternative treatment for PPSUI. Investigators in one population-based US study even found that among all incontinence procedures in their data set, bulking agent injections were the most common, whereas surgical mesh procedures were the least common [1].

Urethral injections of bulking agents have been used to treat urinary incontinence since the early 20th century [4]. Significant advances in this approach began with the introduction of cross-linked collagen, followed by progress with the development of water-based hydrogels. These agents enhance urethral coaptation by increasing bulk at the sphincteric zone, which improves continence. The injection procedure is generally regarded as safe, well tolerated, and minimally invasive, and is often even performed under local anesthesia. However, unlike the healthy female urethra, the male postprostatectomy urethra is typically scarred, which probably reduces its coaptation ability.