New periurethral bulking agent for stress urinary incontinence: modified technique and early results

Durasphere (Carbon Medical Technologies, St. Paul, Minnesota) is a newly approved injectable agent for stress urinary incontinence. Proven and potential advantages include nonimmunogenicity, tissue nonreactivity, efficacy at low injectable volume and durability. A concern regarding use is difficulty involved with application. A modified technique for easier implantation of this agent is described and early results are reported.

The surgical technique follows the standard technique for transurethral implantation of bulking agents. Steps modified to allow easier implantation of Durasphere beads include a single needle stick at the 4 o'clock position, hydrodissection with 1.5 ml 1% lidocaine into the submucosa, gradual withdrawal/advancement or rotation of the needle tip after resistance is noted and holding the needle in position for an additional 10 seconds after proper coaptation is achieved to prevent the beads from leaking out of the needle puncture site. Patient charts were retrospectively reviewed. Patient perception of treatment outcomes, a 24-hour pad test and a voiding diary were obtained and analyzed. The strict criteria of the Groutz-Blaivas score were applied as an additional measure of outcome.

Of 70 patients 46 (65.7%) for whom full contact information was available responded. Patient age was 46 to 83 years (mean 69.4). A history of a failed prior anti-incontinence procedure was recorded in 15 patients (32.6%) and coexisting symptoms of urge incontinence or urodynamically proven detrusor instability was evident in 29 (63%) and 5 (10.8%), respectively. Bulking agent was delivered at 1 to 3 sessions (mean 1.52) 1 to 3 months apart with 2 to 6 ml (3.2 ml) injected per session. Excellent or good coaptation was achieved in 92% of injections. At a followup of up to 18 months (mean 9.4) 6 (13%), 24 (52.2%) and 16 (34.7%) patients considered themselves cured or improved, or treatment to have failed, respectively. Of the 36 patients who completed a 24-hour pad test 18 (50%), 2 (5.5%) and 16 (44.4%) had a urine loss of 8 or less, 9 to 20 and greater than 20 gm, respectively. Results of the voiding diary and the Groutz-Blaivas score are provided.

The modified technique of Durasphere injection allows easy implantation with good coaptation in the majority of patients. Early results are encouraging. Further research may reveal whether the improved delivery techniques translate into improved outcomes with more durable results compared with other approved bulking agents.