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Macroplastique — Polydimethylsiloxane (PDMS)

Macroplastique (Cogentix Medical / Uroplasty, now Laborie Medical) is a nonbiodegradable, particulate silicone-based urethral bulking agent for female stress urinary incontinence (SUI) due to intrinsic sphincter deficiency (ISD). FDA-approved via PMA in 2006; in clinical use for > 30 years.[1]

Composition & Material Properties​

  • Active: highly textured cross-linked polydimethylsiloxane (PDMS) solid macroparticles — a medical-grade silicone elastomer.[1]
  • Carrier: polyvinylpyrrolidone (PVP / povidone) hydrogel, which is gradually absorbed and excreted, leaving the silicone particles in situ.[1]
  • Particle size: majority > 100 μm — specifically engineered to minimize migration (particles < 70 μm migrate; > 100 μm do not).[2]
  • Nonbiodegradable silicone particles; permanent.

Preclinical canine data: large-particle PDMS (median 110 μm) produced an encapsulated fibrous sheath without local migration and without granuloma formation, whereas small-particle formulations (median 73 μm) dissipated with both local and distant migration.[2]

Mechanism​

Macroplastique augments periurethral bulk and coaptation. Silicone particles provoke a marked foreign-body inflammatory reaction that produces firm, stable nodules within the periurethral submucosa. The PVP carrier is gradually absorbed; the silicone particles become encapsulated in a fibrous sheath, creating permanent focal expansion of periurethral tissue.[2][3]

This is fundamentally different from Bulkamid (polyacrylamide hydrogel), which integrates with tissue through collagen infiltration into the gel matrix rather than foreign-body encapsulation.

Injection Technique​

Macroplastique Implantation System (MIS) — Non-Endoscopic​

The MIS is a dedicated transurethral device with pre-set needle positions at 3, 9, and 12 o'clock in the proximal urethra; no cystoscopic guidance required. Operator acceptance excellent / acceptable in 95–100% of cases; 74.3% success at 3 months, comparable to endoscopic results.[4][5]

Endoscopic (Cystoscopy-Guided)​

Submucosal injection at the proximal urethra / bladder neck under direct urethroscopic visualization, with real-time assessment of coaptation.

Procedural details​

  • Anesthesia: local (periurethral lidocaine); sedation or GA optional.[4][6]
  • Setting: office or outpatient; ~30 minutes.[7]
  • Volume: mean 5–6.3 mL per session — markedly higher than Bulkamid.[4][8]
  • Reinjection: ~34% in the ROSE registry required a second injection.[9]

Optimal Placement​

3D endovaginal ultrasound has identified two predictors of success:[10][11]

  • Proximal urethral location > midurethral placement (p = 0.036).
  • Circumferential periurethral distribution — odds 13.6× in the success vs failure group.
  • Combined proximal + circumferential placement: OR 22 (95% CI 3.05–203.49) for success.

Indications​

Female SUI due to intrinsic sphincter deficiency, especially in:[8][12][13]

  • ISD with a well-supported, non-hypermobile urethra.
  • Patients who wish to avoid more invasive surgery.
  • Elderly / medically unfit candidates.
  • Recurrent SUI after failed midurethral sling.

Predictors of failure: history of radical pelvic surgery (independent predictor of subjective and objective failure) and low surgeon experience on multivariate analysis.[12]

Clinical Efficacy​

Pivotal RCT (Macroplastique vs Contigen collagen)​

Multicenter, randomized, single-blind, n = 247 with ISD:[14]

  • ≥ 1 Stamey-grade improvement at 12 mo: 61.5% MPQ vs 48% Contigen (significant).
  • Dry / cure: 36.9% MPQ vs 24.8% Contigen (p < 0.05).

Meta-Analysis (Ghoniem & Miller 2013)​

WindowImprovement (95% CI)Cure / Dry (95% CI)
Short-term (≤ 6 mo)75% (69–81%)43% (33–54%)
Mid-term (6–18 mo)73% (62–83%)37% (28–46%)
Long-term (> 18 mo)64% (57–71%)36% (27–46%)

Higher reinjection rates were associated with better long-term outcomes; no serious AEs across the pooled data.[15]

Long-Term Outcomes​

StudyDesignnFollow-upOutcome
ROSE 5-yearProspective multicenter274 (147 at 5 yr)5 yr47.6% Stamey improvement; I-QoL 45 → 70.9; 68% satisfaction at 3 yr.[16]
Kusin 2024Retrospective single center1067.4 yr median43% overall success; 54% after 1 injection; 17% of failures progressed to sling.[8]
Serati 2019Prospective cohort85≥ 3 yr49% subjective, 47% objective cure; no significant deterioration over time.[12]
Ghoniem 2010Durability study6724 mo84% sustained success from 12 mo; 67% dry at 24 mo.[17]
Zullo 2005Prospective615 yr18% cure, 39% improvement, 57% success.[13]
Sheriff 1997Retrospective342 yr90% success at 1 mo → 48% at 2 yr.[18]

After Failed Midurethral Sling​

Meta-analysis (Braga 2022): pooled 84% (95% CI 77–90%) cure / improvement for Macroplastique after failed MUS vs 80% (95% CI 74–85%) for Bulkamid — no significant difference.[19]

Macroplastique vs Bulkamid​

No head-to-head RCT exists; AUA/SUFU 2023 notes inadequate data to recommend one injectable over another.[21]

ParameterMacroplastiqueBulkamid
CompositionSilicone macroparticles in PVP2.5% polyacrylamide in water
Particle-basedYes (> 100 μm)No (homogeneous gel)
Volume per session~5–6.3 mL~0.5–1.0 mL per site
DeliveryMIS (non-endoscopic) or cystoscopicCystoscopic only
MechanismForeign-body encapsulationCollagen infiltration
12-mo cure~37%~47%
Urethral exposure2.4% in large seriesNot reported
Reinjection rate~34%~24%
Cure after failed sling84%80%
FDA approvalPMA 2006PMA 2020

Safety Profile​

ROSE 5-yr data — common AEs:[16]

  • UTI: 30.8% (most common)
  • Transient urinary retention: 7.2%
  • Dysuria 47%, de novo urgency 21% (Cochrane data).[1]
  • Mild pain 8%, hematuria 8%, implant leakage 8%.
  • Only 1 device-related SAE (urinary retention, 0.4%) across the entire ROSE study; resolved within 4 months. No late-onset SAEs at 5 years.

Urethral Exposures (Unique to Macroplastique)​

Retrospective series: 14 urethral exposures in 580 cases (2.4%), presenting at median 48 months after injection.[20]

  • Presenting symptoms: urge incontinence 64.3%, SUI 57.1%, recurrent UTI 42.9%, urgency 28.9%, retention 14.3%.
  • Median 2 sessions; median 4.5 mL.
  • Treatment: blunt / sharp / electrocautery excision in 10/14; no postexcision complications; improvement in urinary symptoms.
  • The authors note this complication had not previously been reported by the manufacturer.

Particle Migration​

Large particle size (> 100 μm) minimizes migration. In canine work, large particles produced encapsulated sheaths without local migration; distant migration was observed in 1 of 6 dogs (short-term) with large particles; both local and distant migration with small particles.[2]

FDG-PET Pitfall​

Macroplastique deposits can show intense FDG uptake mimicking pelvic neoplasm — an important imaging pitfall during oncologic surveillance.[22]

Male Post-Prostatectomy SUI​

The only RCT in this setting compared Macroplastique to artificial urinary sphincter (AUS) (n = 45):[23][7]

  • AUS more likely to achieve dryness overall (82% vs 46%; OR 5.67), but the difference was significant only for total incontinence (OR 8.89).
  • For minimal incontinence, no significant difference between AUS and Macroplastique.
  • AUS had more severe complications (23% vs 13%) and higher cost.
  • Authors' conclusion: Macroplastique should be the treatment of choice for minimal post-prostatectomy SUI; AUS preferred for total incontinence.

Series of 50 men with repeated injections (mean 2.6 sessions, mean total 7.1 mL): 60% achieved dryness, though multiple sessions were typically required.[24]

Pediatric Vesicoureteral Reflux​

Macroplastique has been used for endoscopic subureteric injection for VUR — and may be superior to dextranomer / hyaluronic acid (Deflux):[25][26][27]

  • Largest prospective comparative study (n = 275, 399 ureters): full correction 90% Macroplastique vs 81% Deflux (p < 0.05).[26]
  • Cochrane review (2 studies, n = 513): Macroplastique 50% reduction in persistent VUR at 3 mo (RR 0.50; 95% CI 0.33–0.78) and 46% reduction at 12 mo (RR 0.54; 95% CI 0.35–0.83) vs Deflux (moderate certainty).[25]
  • Network meta-analysis (2026, 10 RCTs, n = 1,179): Macroplastique ranked third in success rate after Lich-Gregoir and Politano-Leadbetter open techniques, ahead of Cohen, PPC, and Deflux.[27]
  • Complications: moderately higher temporary pelvicaliceal dilatation vs Deflux (RR 1.85; 95% CI 1.02–3.35); 3 cases of ureteral obstruction.[25]

The AUA VUR Guideline lists Macroplastique alongside Deflux as an endoscopic option (overall endoscopic success 83% after 1 injection vs 98.1% for open surgery).[28]

Guideline Position​

AUA/SUFU 2023: bulking agents have a role in patients who wish to avoid more invasive surgery, prioritize shorter recovery, or have insufficient improvement after a prior anti-incontinence procedure. Inadequate data to recommend one injectable over another. Erosions noted with some agents but not with Bulkamid specifically.[21]

Regulatory Status​

  • FDA PMA approval (2006) for female SUI due to ISD.[1]
  • CE-marked in Europe since the early 1990s.
  • ROSE registry (P040050/PAS001) was an FDA-mandated post-approval study.[9]
  • Not a mesh product — unaffected by FDA mesh restrictions.

Advantages​

  • > 30 years of clinical experience; among the longest-established bulking agents.
  • Can be performed without cystoscopic guidance via MIS.
  • Statistically superior to Contigen collagen in the pivotal RCT.
  • Durable (43% success at 7.4 yr median).
  • Excellent safety in ROSE 5-yr data (no late-onset SAEs).
  • Effective for recurrent SUI after failed sling (84% pooled).
  • Potentially superior to Deflux for pediatric VUR.

Limitations​

  • Particulate — theoretical migration risk (minimized but not eliminated).[2]
  • Urethral exposures 2.4% in one large series, median 48 mo — not previously reported by manufacturer.[20]
  • FDG-PET pitfall can mimic neoplasm.[22]
  • Higher injected volumes vs Bulkamid (~5–6 mL vs ~2–4 mL total).
  • Foreign-body reaction with firm nodules rather than tissue integration.
  • Reinjection rate ~34%.
  • Declining cure over time (43% short-term → 36% long-term).[15]
  • No head-to-head RCT vs Bulkamid.
  • Lower objective cure than MUS.

See also: Bulkamid, Durasphere, Coaptite, Urethral Bulking Agents (procedure).

References​

1. Kirchin V, Page T, Keegan PE, et al. Urethral Injection Therapy for Urinary Incontinence in Women. Cochrane Database of Systematic Reviews. 2017;7:CD003881. doi:10.1002/14651858.CD003881.pub4

2. Henly DR, Barrett DM, Weiland TL, et al. Particulate Silicone for Use in Periurethral Injections: Local Tissue Effects and Search for Migration. The Journal of Urology. 1995;153(6):2039-2043.

3. Radley SC, Chapple CR, Lee JA. Transurethral Implantation of Silicone Polymer for Stress Incontinence: Evaluation of a Porcine Model and Mechanism of Action in Vivo. BJU International. 2000;85(6):646-650. doi:10.1046/j.1464-410x.2000.00515.x

4. Tamanini JT, D'Ancona CA, Tadini V, Netto NR. Macroplastique Implantation System for the Treatment of Female Stress Urinary Incontinence. The Journal of Urology. 2003;169(6):2229-2233. doi:10.1097/01.ju.0000067472.94016.e8

5. Henalla SM, Hall V, Duckett JR, et al. A Multicentre Evaluation of a New Surgical Technique for Urethral Bulking in the Treatment of Genuine Stress Incontinence. BJOG. 2000;107(8):1035-1039. doi:10.1111/j.1471-0528.2000.tb10409.x

6. Tamanini JT, D'Ancona CA, Netto NR. Treatment of Intrinsic Sphincter Deficiency Using the Macroplastique Implantation System: Two-Year Follow-Up. Journal of Endourology. 2004;18(9):906-911. doi:10.1089/end.2004.18.906

7. Silva LA, Andriolo RB, Atallah ÁN, da Silva EM. Surgery for Stress Urinary Incontinence Due to Presumed Sphincter Deficiency After Prostate Surgery. Cochrane Database of Systematic Reviews. 2014;(9):CD008306. doi:10.1002/14651858.CD008306.pub3

8. Kusin SB, Carroll TF, Alhalabi F, Christie AL, Zimmern PE. Long-Term Outcomes With Macroplastique in Women With Stress Urinary Incontinence Secondary to Intrinsic Sphincter Deficiency. Urology. 2024;185:36-43. doi:10.1016/j.urology.2023.12.019

9. Ghoniem G, Farhan B, Chowdhury ML, Chen Y. Safety and Efficacy of Polydimethylsiloxane (Macroplastique®) in Women With Stress Urinary Incontinence: Analysis of Data From Patients Who Completed Three Years Follow-Up. International Urogynecology Journal. 2021;32(10):2835-2840. doi:10.1007/s00192-021-04827-6

10. Hegde A, Smith AL, Aguilar VC, Davila GW. Three-Dimensional Endovaginal Ultrasound Examination Following Injection of Macroplastique for Stress Urinary Incontinence: Outcomes Based on Location and Periurethral Distribution of the Bulking Agent. International Urogynecology Journal. 2013;24(7):1151-1159. doi:10.1007/s00192-012-1983-9

11. Poon CI, Zimmern PE. Role of Three-Dimensional Ultrasound in Assessment of Women Undergoing Urethral Bulking Agent Therapy. Current Opinion in Obstetrics & Gynecology. 2004;16(5):411-417. doi:10.1097/00001703-200410000-00010

12. Serati M, Soligo M, Braga A, et al. Efficacy and Safety of Polydimethylsiloxane Injection (Macroplastique) for the Treatment of Female Stress Urinary Incontinence: Results of a Series of 85 Patients With ≥ 3 Years of Follow-Up. BJU International. 2019;123(2):353-359. doi:10.1111/bju.14550

13. Zullo MA, Plotti F, Bellati F, et al. Transurethral Polydimethylsiloxane Implantation: A Valid Option for the Treatment of Stress Urinary Incontinence Due to Intrinsic Sphincter Deficiency Without Urethral Hypermobility. The Journal of Urology. 2005;173(3):898-902. doi:10.1097/01.ju.0000152568.40199.a8

14. Ghoniem G, Corcos J, Comiter C, et al. Cross-Linked Polydimethylsiloxane Injection for Female Stress Urinary Incontinence: Results of a Multicenter, Randomized, Controlled, Single-Blind Study. The Journal of Urology. 2009;181(1):204-210. doi:10.1016/j.juro.2008.09.032

15. Ghoniem GM, Miller CJ. A Systematic Review and Meta-Analysis of Macroplastique for Treating Female Stress Urinary Incontinence. International Urogynecology Journal. 2013;24(1):27-36. doi:10.1007/s00192-012-1825-9

16. Ghoniem G, Lane F, Farhan B, et al. Five-Year Follow-Up Study on Safety and Efficacy of Macroplastique® in Female Patients With Stress Urinary Incontinence (The ROSE Study). International Urogynecology Journal. 2025. doi:10.1007/s00192-025-06163-5

17. Ghoniem G, Corcos J, Comiter C, Westney OL, Herschorn S. Durability of Urethral Bulking Agent Injection for Female Stress Urinary Incontinence: 2-Year Multicenter Study Results. The Journal of Urology. 2010;183(4):1444-1449. doi:10.1016/j.juro.2009.12.038

18. Sheriff MK, Foley S, McFarlane J, Nauth-Misir R, Shah PJ. Endoscopic Correction of Intractable Stress Incontinence With Silicone Micro-Implants. European Urology. 1997;32(3):284-288.

19. Braga A, Caccia G, Papadia A, et al. Urethral Bulking Agents for the Treatment of Recurrent Stress Urinary Incontinence: A Systematic Review and Meta-Analysis. Maturitas. 2022;163:28-37. doi:10.1016/j.maturitas.2022.05.007

20. Ramirez-Caban L, Malekzadeh M, Ossin DA, Hurtado EA. Clinical Presentation and Treatment of Macroplastique® Urethral Exposures: A Retrospective Case Series. International Urogynecology Journal. 2022;33(3):681-687. doi:10.1007/s00192-021-04910-y

21. Kobashi KC, Vasavada S, Bloschichak A, et al. Updates to Surgical Treatment of Female Stress Urinary Incontinence (SUI): AUA/SUFU Guideline (2023). The Journal of Urology. 2023;209(6):1091-1098. doi:10.1097/JU.0000000000003435

22. Richard C, Dejust S, Moubtakir A, Bruna-Muraille C, Morland D. Periurethral Mass Mimicking Neoplasm After Injection of Macroplastique for Postprostatectomy Stress Incontinence: A Pitfall on 18F-FDG PET/CT. Clinical Nuclear Medicine. 2018;43(5):381-382. doi:10.1097/RLU.0000000000002043

23. Imamoglu MA, Tuygun C, Bakirtas H, Yiğitbasi O, Kiper A. The Comparison of Artificial Urinary Sphincter Implantation and Endourethral Macroplastique Injection for the Treatment of Postprostatectomy Incontinence. European Urology. 2005;47(2):209-213. doi:10.1016/j.eururo.2004.08.019

24. Kylmälä T, Tainio H, Raitanen M, Tammela TL. Treatment of Postoperative Male Urinary Incontinence Using Transurethral Macroplastique Injections. Journal of Endourology. 2003;17(2):113-115. doi:10.1089/08927790360587450

25. Williams G, Hodson EM, Craig JC. Interventions for Primary Vesicoureteric Reflux. Cochrane Database of Systematic Reviews. 2019;2:CD001532. doi:10.1002/14651858.CD001532.pub5

26. Moore K, Bolduc S. Prospective Study of Polydimethylsiloxane vs Dextranomer/Hyaluronic Acid Injection for Treatment of Vesicoureteral Reflux. The Journal of Urology. 2014;192(6):1794-1799. doi:10.1016/j.juro.2014.05.116

27. Ku HC, Huang FH. Comparison of Interventions in Pediatric Primary Vesicoureteral Reflux: A Network Meta-Analysis. Journal of Pediatric Surgery. 2026;61(4):162769. doi:10.1016/j.jpedsurg.2025.162769

28. Peters CA, Skoog SJ, Arant BS, et al. Summary of the AUA Guideline on Management of Primary Vesicoureteral Reflux in Children. The Journal of Urology. 2010;184(3):1134-1144. doi:10.1016/j.juro.2010.05.065