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Deflux — Dextranomer / Hyaluronic Acid Copolymer (Dx/HA, NASHA/Dx)

Deflux (Q-Med AB, Uppsala / Galderma) is a biodegradable, biocompatible injectable bulking agent of dextranomer microspheres in non-animal stabilized hyaluronic acid (NASHA) gel. FDA-approved in 2001 for endoscopic treatment of vesicoureteral reflux (VUR) grades II–IV in children — the most widely used VUR bulking agent worldwide.[1][2] A related formulation (Solesta) is FDA-approved for fecal incontinence.

Composition & Material Properties​

  • Dextranomer microspheres: cross-linked dextran beads 80–250 μm — above the 80 μm phagocytosis threshold.[1][3]
  • Carrier: non-animal stabilized hyaluronic acid (NASHA) — biosynthetic cross-linked HA gel.
  • Biodegradable: HA gradually absorbed; dextranomer microspheres act as micro-scaffolds promoting fibroblast ingrowth and new collagen that replaces implant volume.[3]
  • Biocompatible / non-immunogenic: HA is a natural polysaccharide (N-acetyl-D-glucosamine + β-glucuronic acid); non-animal-derived — no skin testing required.[4]
  • Viscoelastic — easy to inject in a well-controlled manner.

Mechanism​

Sub-ureteric injection creates a mound that buttresses the intramural ureter, restoring the flap-valve anti-reflux mechanism:[1][3][5]

  1. Immediate phase — gel bolus physically supports the ureter.
  2. Tissue-integration phase — dextranomer microspheres scaffold fibroblast ingrowth + collagen deposition.
  3. Maturation phase — HA absorbed; microspheres become encapsulated by fibrous tissue with a granulomatous foreign-body reaction (giant cells in 94% of histologic specimens); calcification in 9/13 specimens; CD3+/CD20+ lymphocytic infiltrate increases over time.[5][7]
  4. Volume maintenance — ~21% reduction at 2 weeks, then stable with ~65% volume retention at 24–36 months.[6]

Injection Technique​

Endoscopic, cystoscopic guidance — typical day-case procedure (~15 min) under GA in children.[1][8]

  • Volume: 0.4–1.0 mL per ureter (mean ~0.83 mL).

Three injection techniques:[8][9][11][12][13]

  • STING (Subureteral Transurethral Injection) — needle at 6 o'clock below the orifice; creates a volcano-mound. Single-injection success 67–79%.
  • HIT (Hydrodistention Implantation Technique) — ureter hydrodistended, needle advanced intraluminally submucosally; coapts the intramural wall. Single-injection success 82.5% — significantly better than STING (pooled OR 0.54, 95% CI 0.42–0.69).
  • Double HIT — proximal + distal intraluminal injections coapting tunnel and orifice. Now standard — 92% of US pediatric urologists report routine use, vs 24% STING and 34% HIT.

Indications​

FDA-approved: VUR grades II–IV in children.[14]

Widely used (including off-label):[1][15][16]

  • VUR grades I–V (grade V off-label).
  • First-line for VUR requiring intervention (e.g., breakthrough UTI on prophylaxis).
  • Complex anatomy: duplex systems, bladder diverticula, ectopic ureters.[16][17]
  • VUR in infants (with lower success rates).

Clinical Efficacy​

Resolution by VUR Grade (Meta-Analysis, n = 5,527)[18]​

GradeSingle-injection resolution
I–II79%
III72%
IV63%
V51%

Major Studies​

StudyDesignn (ureters)Follow-upOutcome
Puri 2012Prospective single-center2,341 (1,551 children)5.6 yr median87.1% resolution after 1st, 11.3% after 2nd, 1.6% after 3rd; 4.6% febrile UTI; no reimplantation needed.[10]
Friedmacher 2018Prospective high-grade1,287 (851 children)8.5 yr median69.5% after 1st injection (grade IV 70.4%, V 61.9%); 5.1% febrile UTI post-resolution.[15]
Tiboni 2025Retrospective grade 4–549 patients32 mo median84% no further intervention after 1 injection, 98% after subsequent; males significantly better than females.[19]
Moore 2014Prospective vs Macroplastique197 (Deflux)4.3 yr median81% Deflux vs 90% Macroplastique resolution (p < 0.05).[20]
Lee 2009Retrospective long-term3371 yr73% initial success; only 74% of initial successes maintained at 1 yr → overall 1-yr success 46.1%.[21]

Swedish Reflux Trial[18][22]​

Landmark open RCT (n = 203, age 1–2 yr, grade III–IV VUR) — prophylaxis vs endoscopic Deflux vs surveillance:

  • VUR resolution / downgrading at 2 yr: endoscopic 71% vs prophylaxis 39% vs surveillance 47% (significant).
  • After 1–2 injections, 86% had no / grade I–II reflux.
  • Recurrent dilating reflux in 20% by 2 yr — durability concern.
  • No significant difference in recurrent febrile UTIs or further renal scarring between endoscopic vs prophylaxis or surveillance.

This is the key caveat: Deflux is superior at resolving the radiographic finding but does not translate into reduced UTIs or renal scarring vs antibiotic prophylaxis.

Deflux vs Other VUR Agents​

vs Macroplastique​

Cochrane 2019 (2 studies, n = 513): Macroplastique probably reduces persistent VUR vs Deflux:[23]

  • 50% reduction in persistent VUR at 3 mo (RR 0.50; 95% CI 0.33–0.78).
  • 46% reduction at 12 mo (RR 0.54; 95% CI 0.35–0.83).
  • Moderate certainty.
  • Macroplastique has moderately higher transient pelvicaliceal dilatation (RR 1.85; 95% CI 1.02–3.35).

Moore 2014 prospective (399 ureters) confirms: Macroplastique 90% vs Deflux 81% resolution.[20]

vs Vantris (Polyacrylate Polyalcohol Copolymer)​

ParameterDeflux (Dx/HA)Vantris (PPC)
BiodegradabilityAbsorbableNon-absorbable
Ease of injectionEasierMore difficult
Obstruction riskLowerHigher
DurabilityLoses efficacy over timePotentially more durable
[16]

Safety Profile​

Early complications ~1%; late complications are the defining concern.[14][24][25]

Common / expected​

  • Febrile UTI post-resolution: 4–25% across long-term studies.[10][15]
  • Neocontralateral reflux: ~4.5% (new VUR in previously unaffected ureter).[8]
  • Granulomatous foreign-body reaction: 94% of histologic specimens (expected).[5]
  • Calcification: 69% (9/13) of excised specimens.[5]

Delayed Ureteral Obstruction — The Key Late Complication​

  • Incidence: < 1–2%.[24][25][26]
  • Timing: 1 month to 8 years post-injection.[14][25][27]
  • Mechanism: foreign-body granuloma + calcification + fibrosis → progressive ureteral narrowing.
  • Risk factors: voiding dysfunction / neurogenic bladder (80% of early cases), off-label use, high-volume injection (> 1.0 mL).[26][28]
  • Asymptomatic renal function loss has been documented years after treatment.[14][24]
  • Management: temporary stent for early obstruction; ureteral reimplantation for delayed.

Documented case patterns:

  • Delayed obstruction at 18–52 months with off-label use → loss of renal function.[14]
  • Bilateral delayed partial obstruction at 16 mo after bilateral high-volume injection.[28]
  • Calcification masquerading as renal colic > 5 years post-injection.[27]
  • Asymptomatic severe hydroureteronephrosis identified 8 years post-treatment.[24]

Implant Calcification​

  • Well-documented histologically.[5][29]
  • Can mimic ureteral stones on imaging (reconstructive-urology-relevant signal in adult patients with prior pediatric Deflux).[29][27]
  • May contribute to delayed obstruction.

Late Reflux Recurrence​

  • Swedish trial: 20% recurrent dilating reflux at 2 yr.[22]
  • Lee 2009: only 74% of initial successes maintained at 1 yr → 46.1% true 1-yr success.[21]
  • Attributable to the biodegradable nature.

Volume Retention & Durability​

Sonographic volumetry:[6]

  • 2 wk: 79% retained (21% initial reduction)
  • 12 wk: 78%
  • 24–36 mo: 65% retained, stable thereafter.
  • "Mega-implants" (greater-than-expected retention) → 94% cure vs 75% micro-implants vs 70% non-visualized.

Bladder ultrasound detects mounds in 89% of low-grade and 43.3% of high-grade at last follow-up — a potential VCUG-sparing surveillance tool.[30]

Predictive Factors​

Lower success:[15][19][16][8][31]

  • Higher VUR grade.
  • Age < 1 yr.
  • Baseline renal scarring.
  • Female sex (Tiboni 2025).
  • Bladder-bowel dysfunction (BBD) — reduces endoscopic success (does not affect open surgical cure).
  • STING vs HIT/Double HIT.
  • Early in surgeon's learning curve (60% in first 20 vs 80% in last 20).

Not associated: bilaterality, duplex anatomy, DMSA defects.

Duplex Systems​

Specific evaluation in complete duplex systems with intermediate/high-grade VUR:[17]

  • 123 children (136 refluxing units), 6.7 yr mean.
  • Resolution: 68.4% after 1st injection; 25.7% after 2nd; 5.9% after 3rd.
  • 4.1% febrile UTI; no reimplantations; no significant complications.

Solesta — Same Technology for Fecal Incontinence​

The same Dx/HA technology is marketed as Solesta for adult fecal incontinence, FDA-approved 2011:[32][33][34]

  • Submucosal injection into the proximal anal canal augments the sphincter seal.
  • Pivotal sham-controlled RCT (n = 206): 52% response (≥ 50% FI episode reduction) vs 31% sham at 6 mo (p = 0.0089).
  • 36-mo follow-up (n = 283): 18.9% reintervention; significant CCS and FI-QoL improvement; no SAEs.
  • Common AEs: proctalgia 14%, fever 8%, rectal bleeding 7%.
  • Long-term durability concern: implant volume declines on US.
  • ASCRS 2023 does not routinely recommend injectable bulking agents for FI (limited improvement over placebo, diminishing durability, cost).[35]

Guideline Position​

AUA Primary VUR Guideline: endoscopic injection (Deflux / Macroplastique) is a recognized modality.[31]

  • Open surgical success 98.1% vs 83.0% endoscopic after 1 injection.
  • BBD does not affect open surgical cure; does affect endoscopic cure.
  • Choice balances morbidity / efficacy / ongoing reflux risk / family preference.

Cochrane 2019: vs antibiotic prophylaxis alone, endoscopic correction may make little or no difference to symptomatic febrile UTI or progressive renal damage (low certainty). Macroplastique may be superior to Deflux.[23]

Regulatory Status​

  • FDA-approved 2001 for grade II–IV VUR.[14]
  • Grade V off-label.
  • Solesta approved 2011 for fecal incontinence.[35]
  • CE-marked.

Why This Matters for Reconstructive Urology​

The reconstructive urologist encounters Deflux in two settings:

  1. Adult / late-adolescent patients with prior pediatric Deflux presenting with:
    • Ureteral calcifications on imaging mimicking calculi (mound calcification well-documented).[5][29]
    • Delayed obstruction with hydroureteronephrosis and asymptomatic renal function loss — sometimes 5–8 years out — that may require ureteral stenting or reimplantation.[14][24][25]
  2. Persistent or recurrent VUR after Deflux requiring definitive open or robotic reimplantation.

Advantages​

  • > 20 years of clinical data — largest VUR bulking-agent evidence base.
  • Biodegradable, biocompatible, non-immunogenic.
  • 15-min outpatient procedure.
  • High single-injection resolution (69–87%).
  • Easily repeatable.
  • Effective in complex anatomy (duplex, high-grade).
  • Lower obstruction risk than Vantris.
  • Dual FDA approval (Solesta for FI).

Limitations​

  • Biodegradable → declining efficacy over time (20% recurrent dilating reflux at 2 yr; 46.1% true 1-yr success in some series).[22][21]
  • Inferior to open surgery (83% vs 98.1%).[31]
  • Inferior to Macroplastique for VUR resolution (50% higher persistent-VUR risk, moderate-certainty evidence).[23][20]
  • Delayed ureteral obstruction, sometimes with asymptomatic renal function loss.[14][24][25]
  • Implant calcification in up to 69% of histologic specimens.[5][29]
  • Does not reduce febrile UTIs or renal scarring vs antibiotic prophylaxis.[18][22]
  • Significant learning curve.[8]
  • BBD reduces success.[31]
  • GA required in children.
  • Long-term surveillance mandatory.
  • Solesta (FI) durability limited.[35]

See also: Macroplastique, Bulkamid, Coaptite, Durasphere.

References​

1. Kirsch AJ, Cooper CS, Läckgren G. Non-Animal Stabilized Hyaluronic Acid/Dextranomer Gel (NASHA/Dx, Deflux) for Endoscopic Treatment of Vesicoureteral Reflux: What Have We Learned Over the Last 20 Years? Urology. 2021;157:15-28. doi:10.1016/j.urology.2021.07.032

2. Puri P, Chertin B, Velayudham M, Dass L, Colhoun E. Treatment of Vesicoureteral Reflux by Endoscopic Injection of Dextranomer/Hyaluronic Acid Copolymer: Preliminary Results. The Journal of Urology. 2003;170(4 Pt 2):1541-1544. doi:10.1097/01.ju.0000083924.44779.80

3. Stenberg A, Läckgren G. A New Bioimplant for the Endoscopic Treatment of Vesicoureteral Reflux: Experimental and Short-Term Clinical Results. The Journal of Urology. 1995;154(2 Pt 2):800-803. doi:10.1097/00005392-199508000-00127

4. Liao YH, Jones SA, Forbes B, Martin GP, Brown MB. Hyaluronan: Pharmaceutical Characterization and Drug Delivery. Drug Delivery. 2005;12(6):327-342. doi:10.1080/10717540590952555

5. Stenberg A, Larsson E, Läckgren G. Endoscopic Treatment With Dextranomer-Hyaluronic Acid for Vesicoureteral Reflux: Histological Findings. The Journal of Urology. 2003;169(3):1109-1113. doi:10.1097/01.ju.0000053013.49676.89

6. McMann LP, Scherz HC, Kirsch AJ. Long-Term Preservation of Dextranomer/Hyaluronic Acid Copolymer Implants After Endoscopic Treatment of Vesicoureteral Reflux in Children: A Sonographic Volumetric Analysis. The Journal of Urology. 2007;177(1):316-320. doi:10.1016/j.juro.2006.08.144

7. Routh JC, Ashley RA, Sebo TJ, et al. Histopathological Changes Associated With Dextranomer/Hyaluronic Acid Injection for Pediatric Vesicoureteral Reflux. The Journal of Urology. 2007;178(4 Pt 2):1707-1710. doi:10.1016/j.juro.2007.03.165

8. Kirsch AJ, Perez-Brayfield MR, Scherz HC. Minimally Invasive Treatment of Vesicoureteral Reflux With Endoscopic Injection of Dextranomer/Hyaluronic Acid Copolymer: The Children's Hospitals of Atlanta Experience. The Journal of Urology. 2003;170(1):211-215. doi:10.1097/01.ju.0000072523.43060.a0

9. Kirsch AJ, Arlen AM, Lackgren G. Current Trends in Dextranomer Hyaluronic Acid Copolymer (Deflux) Injection Technique for Endoscopic Treatment of Vesicoureteral Reflux. Urology. 2014;84(2):462-468. doi:10.1016/j.urology.2014.04.032

10. Puri P, Kutasy B, Colhoun E, Hunziker M. Single Center Experience With Endoscopic Subureteral Dextranomer/Hyaluronic Acid Injection as First Line Treatment in 1,551 Children With Intermediate and High Grade Vesicoureteral Reflux. The Journal of Urology. 2012;188(4 Suppl):1485-1489. doi:10.1016/j.juro.2012.02.023

11. Kirsch AJ, Perez-Brayfield M, Smith EA, Scherz HC. The Modified STING Procedure to Correct Vesicoureteral Reflux: Improved Results With Submucosal Implantation Within the Intramural Ureter. The Journal of Urology. 2004;171(6 Pt 1):2413-2416. doi:10.1097/01.ju.0000127754.79866.7f

12. Yap TL, Chen Y, Nah SA, et al. STING Versus HIT Technique of Endoscopic Treatment for Vesicoureteral Reflux: A Systematic Review and Meta-Analysis. Journal of Pediatric Surgery. 2016;51(12):2015-2020. doi:10.1016/j.jpedsurg.2016.09.028

13. Kirsch AJ, Arlen AM. Evaluation of New Deflux Administration Techniques: Intraureteric HIT and Double HIT for the Endoscopic Correction of Vesicoureteral Reflux. Expert Review of Medical Devices. 2014;11(5):439-446. doi:10.1586/17434440.2014.929491

14. Papagiannopoulos D, Rosoklija I, Cheng E, Yerkes E. Delayed Obstruction With Asymptomatic Loss of Renal Function After Dextranomer/Hyaluronic Acid Copolymer (Deflux) Injection for Vesicoureteral Reflux: A Close Look at a Disturbing Outcome. Urology. 2017;101:63-66. doi:10.1016/j.urology.2016.09.013

15. Friedmacher F, Colhoun E, Puri P. Endoscopic Injection of Dextranomer/Hyaluronic Acid as First Line Treatment in 851 Consecutive Children With High Grade Vesicoureteral Reflux: Efficacy and Long-Term Results. The Journal of Urology. 2018;200(3):650-655. doi:10.1016/j.juro.2018.03.074

16. Escolino M, Kalfa N, Castagnetti M, et al. Endoscopic Injection of Bulking Agents in Pediatric Vesicoureteral Reflux: A Narrative Review of the Literature. Pediatric Surgery International. 2023;39(1):133. doi:10.1007/s00383-023-05426-w

17. Hunziker M, Mohanan N, Puri P. Dextranomer/Hyaluronic Acid Endoscopic Injection Is Effective in the Treatment of Intermediate and High Grade Vesicoureteral Reflux in Patients With Complete Duplex Systems. The Journal of Urology. 2013;189(5):1876-1881. doi:10.1016/j.juro.2012.11.048

18. Tullus K. Vesicoureteric Reflux in Children. Lancet. 2015;385(9965):371-379. doi:10.1016/S0140-6736(14)60383-4

19. Tiboni SG, Bethell GS, Davidson JR, Farrugia MK. Factors Influencing Success in Endoscopic Treatment of Grade 4-5 Primary Vesicoureteric Reflux (VUR) in Infancy and Childhood. Journal of Pediatric Surgery. 2025;60(3):162157. doi:10.1016/j.jpedsurg.2025.162157

20. 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

21. Lee EK, Gatti JM, DeMarco RT, Murphy JP. Long-Term Followup of Dextranomer/Hyaluronic Acid Injection for Vesicoureteral Reflux: Late Failure Warrants Continued Followup. The Journal of Urology. 2009;181(4):1869-1874. doi:10.1016/j.juro.2008.12.005

22. Holmdahl G, Brandström P, Läckgren G, et al. The Swedish Reflux Trial in Children: II. Vesicoureteral Reflux Outcome. The Journal of Urology. 2010;184(1):280-285. doi:10.1016/j.juro.2010.01.059

23. 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

24. Pham H, Au J, Jones E. Deflux Calcification Leading to Delayed Obstruction and Loss of Renal Function: A Case Report. Urology. 2022;166:246-249. doi:10.1016/j.urology.2022.04.025

25. Rubenwolf PC, Ebert AK, Ruemmele P, Rösch WH. Delayed-Onset Ureteral Obstruction After Endoscopic Dextranomer/Hyaluronic Acid Copolymer (Deflux) Injection for Treatment of Vesicoureteral Reflux in Children: A Case Series. Urology. 2013;81(3):659-662. doi:10.1016/j.urology.2012.11.044

26. Vandersteen DR, Routh JC, Kirsch AJ, et al. Postoperative Ureteral Obstruction After Subureteral Injection of Dextranomer/Hyaluronic Acid Copolymer. The Journal of Urology. 2006;176(4 Pt 1):1593-1595. doi:10.1016/j.juro.2006.06.101

27. Romain J, Fourcade L, Centi J, et al. Delayed-Onset Ureteral Obstruction and Calcification Masquerading as Renal Colic Following Deflux Injection. Urology. 2016;94:218-220. doi:10.1016/j.urology.2016.03.001

28. Nseyo U, Mancini JG, Wiener JS. Symptomatic Bilateral Delayed Partial Ureteral Obstruction After Bilateral Endoscopic Correction of Vesicoureteral Reflux With Dextranomer/Hyaluronic Acid Polymer. Urology. 2013;81(1):184-187. doi:10.1016/j.urology.2012.09.012

29. Palagiri AV, Dangle PP. Distal Ureteral Calcification Secondary to Deflux Injection: A Reality or Myth? Urology. 2011;77(5):1217-1219. doi:10.1016/j.urology.2010.06.047

30. Aboutaleb H, Eldib DB, Farahat Y, Abouelgreed TA, Zanaty F. Efficacy of Bladder Ultrasound in Prediction of Resolution of Vesicoureteral Reflux After Endoscopic Subureteral Hyaluronic Acid/Dextranomer (Deflux) Injection. Urology. 2022;165:299-304. doi:10.1016/j.urology.2022.01.015

31. 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

32. Hoy SM. Dextranomer in Stabilized Sodium Hyaluronate (Solesta®): In Adults With Faecal Incontinence. Drugs. 2012;72(12):1671-1678. doi:10.2165/11209030-000000000-00000

33. Quiroz LH, Galliano DE, da Silva G, et al. Efficacy and Safety of a Nonanimal Stabilized Hyaluronic Acid/Dextranomer in Improving Fecal Incontinence: A Prospective, Single-Arm, Multicenter, Clinical Study With 36-Month Follow-Up. Diseases of the Colon and Rectum. 2023;66(2):278-287. doi:10.1097/DCR.0000000000002348

34. Bharucha AE, Rao SSC, Shin AS. Surgical Interventions and the Use of Device-Aided Therapy for the Treatment of Fecal Incontinence and Defecatory Disorders. Clinical Gastroenterology and Hepatology. 2017;15(12):1844-1854. doi:10.1016/j.cgh.2017.08.023

35. Bordeianou LG, Thorsen AJ, Keller DS, et al. The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Management of Fecal Incontinence. Diseases of the Colon and Rectum. 2023;66(5):647-661. doi:10.1097/DCR.0000000000002776