Beyond the Abstract - Cross-Linked Polydimethylsiloxane Injection for Female Stress Urinary Incontinence: Results of a Multicenter, Randomized, Controlled, Single-Blind Study

BERKELEY, CA (UroToday.com) - Macroplastique® was compared to Contigen® in a non-inferiority study design in 247 women (122 vs. 125 respectively) with intrinsic sphincter deficiency.

Only one repeat treatment was allowed at 3 months. At 12 months after treatment 61.5% of patients who received Macroplastique and 48% of controls had improved 1 Stamey grade. In the Macroplastique group the dry/cure rate was 36.9% compared to 24.8% in the control group (p <0.05). In the Macroplastique and control groups the 1-hour pad weight decrease was 25.4 and 22.8 ml from baseline (p = 0.64), and the mean improvement in Urinary Incontinence Quality of Life Scale score was 28.7 and 26.4 (p = 0.49), respectively.

 

 

 

Urethral Bulking Agents (UBA) injection represents a minimally invasive, office-based approach to SUI. Women with urinary incontinence have realistic expectations from treatment and accept less effective modality, providing it is minimally invasive. In our study of 100 women with stress urinary incontinence (SUI), the majority of them (71%) found a minor surgery, like a transobturator tape, or a clinical procedure, like UBA, most desirable. This study is different from older Macroplastique studies in many ways: first North American, included large number of patients from different centers, blinded to patients, used control (Contigen), used strict criteria for analysis. It also classified and analyzed all genitourinary adverse events that occurred at any time during the study as treatment related whether they were determined by investigating physicians to be treatment-related or not.

Study limitations include the intent-to-treat analysis where all drop outs were analyzed as failures rather than using last value carried forward, which would have given a higher success and cure rate. This is unique to this study (not used in other UBA studies) and the strictest test. Other bulking agents approved by FDA (Coaptite and Durasphere) used last value carried forward for failures. Secondly, the subjects were retreated at only the 3-month point and were not able to get a retreatment at any other time during their 1 year follow up. In reality, a patient can have a retreatment anytime after 3-months. Lastly, from this study there may be patients who still had an OAB urge component remaining after their SUI is resolved, but those patients are not included in the dry group.

The Implant:

The unique nature of the Macroplastique implants is created via a proprietary process rendering a highly textured, soft implant that easily agglomerates with other implants. It is believed this agglomeration property allows for firm anchoring within the submucosal area of the urethra because of the rapid tissue response around and through the open matrix of the material.

The open matrix of an individual Macroplastique implant can be most easily described as being similar to a natural sea sponge with a flexible, three-dimensional structure (note scanning electron micrographs of an individual implant and an agglomeration of implants below). This characteristic allows for the rapid formation of a fibrin net around the implanted material (referred to as a “bolus”) with subsequent robust collagen deposition. The size of an individual, non-agglomerated implant is approximately 150 microns in diameter, and can be as large as 400+ microns.

The large size and compression of the soft, textured implants is the reason for the high resistance of the suspension during delivery, thus requiring a special Administration Device designed to deliver the material in a slow, precise manner.

 


Figure 1: SEM of Individual Macroplastique Implant



Figure 2: SEM of Agglomerated Macroplastique Implants



Figure 3: Macroplastique Administration Device

 



Figure 4: Macroplastique 2.5cc Syringes


The Transurethral Technique:

To get good results, the deposition of Macroplastique should be distal to Bladder neck and into the proximal urethra. The tunneling technique is important to trap the implant. To achieve both criteria, the puncture (entry) should be just above the external sphincter level. Visual coaptation of the mucosa is important.

 

Written by:
Gamal M. Ghoniem, MD, FACS as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.

Cross-Linked Polydimethylsiloxane Injection for Female Stress Urinary Incontinence: Results of a Multicenter, Randomized, Controlled, Single-Blind Study - Abstract

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