Particulate Silicone for Use in Periurethral Injections: Local Tissue Effects and Search for Migration

Abstract

We examined the histologic behavior and migratory tendencies of a silicone-based injectable paste (Macroplastique) with potential application in treating urinary incontinence. Thirteen female dogs were studied. Six received 2 periurethral injections of large-particle paste, with a median diameter of 110 microns, and 7 received similar injections with small-particle paste (median diameter, 73 microns). The paste was radiolabeled with cobalt-57. Histologic analysis was performed at 4 or 9 months. The pathologic appearance revealed intact large-particle injection sites. The small-particle sites had dissipated significantly. This was confirmed by nuclear imaging. Large particles produced an encapsulated fibrous sheath without local migration. There was a histiocytic reaction within the injection site but no granuloma formation. Distant migration was observed in 1 dog (short term, large particle), without an inflammatory response. Migration of silicone occurred locally and distantly in animals that received small particles. X-ray microanalysis confirmed the presence of silicone particles.

Endoscopic treatment of vesicoureteral reflux in children with subureteral dextranomer/hyaluronic acid injection: a single-centre, 7-year experience

“…16,17 Polydimethysiloxan (Silicon, Macroplastique) also shares the same problem, with marked local inflammatory response and migration. 18 There is a real concern because of possible malignant alteration as a result of the influence of silicon on the tissue. 19 Cross-linked bovine collagen (Zyderm, Zypast, GAX-35, GAX-65) has been used as the main alternative to polytetrafluoroethylene.…”

Biocompatibility of Injectable Microspheres

“…Depending on their chemical structure and surface characteristics, most absorbable biological materials and synthetics such as suture materials [78], alginate microspheres [79], polylactic acid, dextran or polymethylacrylate (PMA) particles (Table 2) initiate a temporary foreign body reaction which may remain untreated up to 12 months; whereas granulomas after permanent injectables like PMMA can last up to 5 years [80,81]. Polylactic acid (PLLA) particles of a mean diameter of 60µm, 1.0 mm and 2.2 mm respectively, were implanted subcutaneously on the back of rats [82]. They were surrounded by young fibrous tissue from 3 weeks up to 50 weeks and showed fragmentation and phagocytosis by macrophages and foreign body giant cells after 70 weeks of implantation [82].…”

“…Polylactic acid (PLLA) particles of a mean diameter of 60µm, 1.0 mm and 2.2 mm respectively, were implanted subcutaneously on the back of rats [82]. They were surrounded by young fibrous tissue from 3 weeks up to 50 weeks and showed fragmentation and phagocytosis by macrophages and foreign body giant cells after 70 weeks of implantation [82]. If implanted intradermally, this reaction may clinically be much more obvious than when implanted subdermally or periurethrally (Figure 15).…”

Effects of Macroplastique® Implantation System for stress urinary incontinence and urethral hypermobility in women

“…Macroplastique® is a bulking agent that consists of solid polydimethylsiloxane particles with a mean maximum diameter of 209 μm [10]. After injection, these particles seem to be nonmigratory and will be organized within 6 to 8 weeks in firm nodules with infiltrated collagen and surrounded by a fibrous sheath that is well developed at 9 months [11][12][13][14].…”