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Axonics Sacral Neuromodulation System

The Axonics rechargeable sacral neuromodulation (r-SNM) system was the first FDA-approved rechargeable SNM device — designed to deliver therapy for ≥ 15 years with full-body 1.5T and 3T MRI conditional labeling.[1][2][3][4] Two features that distinguished it from the incumbent Medtronic InterStim at the time of its 2019 launch. Axonics was acquired by Boston Scientific in 2024.

For the mechanism of SNM, indication-specific outcomes, and the rechargeable-vs-non-rechargeable real-world signal that applies across both manufacturers, see Medtronic InterStim.

History​

  • 2012 — Axonics Modulation Technologies founded (Irvine, CA), targeting the two major InterStim limitations: short battery life (median 5.9 yr) and head-only-1.5T MRI labeling.[1][3]
  • 2016 — CE Mark in Europe; RELAX-OAB post-market study initiated.[5]
  • 2017 — European post-market data published.[3]
  • 2019 — FDA approval for UUI, urgency-frequency, and non-obstructive urinary retention (ARTISAN-SNM pivotal).[1]
  • 2019 — FDA approval extended to fecal incontinence.[6]
  • 2020–2021 — 1- and 2-year ARTISAN outcomes published.[7][8]
  • 2024 — Boston Scientific acquired Axonics (~$3.7B), integrating it alongside AMS 800 in the BSCI urology portfolio.

Device Specifications​

FeatureAxonics r-SNMInterStim IIInterStim Micro
IPG typeRechargeableNon-rechargeableRechargeable
IPG volume~5 cm³~22 cm³~5 cm³
Battery≥ 15 yrMedian 5.9 yr~15 yr
MRIFull-body 1.5T + 3THead-only 1.5TFull-body 1.5T + 3T
Charging1–2×/wk, ~1 hNoneWeekly
LeadQuadripolar tinedTined 3889Tined 3889
Patient appYes (BT)NoYes (BT)
Implant approachSingle-stage validatedStaged / PNEStaged / PNE

References: [1][2][3][4][7][8]

Successor Variants (Boston Scientific era)​

  • Axonics F15 — recharge-free; manufacturer-rated battery 17.6 yr at 1 mA, > 20 yr at lower settings; ~20% smaller than Medtronic InterStim X.
  • Axonics R20 — recharge-free, 20+ yr lifespan; smallest form factor.

These post-acquisition options ended the "rechargeable vs recharge-free" trade-off — both formats are available within the Axonics portfolio.

Key Design Advantages​

  1. Rechargeable ≥ 15-yr battery — eliminates routine replacement surgeries (InterStim II median 5.9 yr means a 50-year-old could otherwise require 3–5 replacements over their lifetime).[1][3]
  2. Full-body 1.5T + 3T MRI — important given ~50–75% of patients will require an MRI during device life.[4]
  3. Miniaturized ~5 cm³ IPG — ~75% smaller than InterStim II, improving comfort.[2][3]
  4. Single-stage implantation validated in ARTISAN — cost-effective when success rates exceed 61–65% (which contemporary rates consistently do).[1][7]

Pivotal Clinical Trials​

RELAX-OAB (European Post-Market) — n = 51[5][9]​

  • 3 mo: 91% of test responders continued; significant ICIQ-OABqol improvement across all domains; 19.6% device-related AE (stimulation discomfort, resolved with reprogramming); 1 infection-related explantation.
  • 12 mo: 94% of test responders continued; 21.1-point ICIQ-OABqol improvement; 84% satisfied; 98% found recharging acceptable; no serious device-related AEs.

ARTISAN-SNM (US Pivotal) — n = 129 UUI[1][7][8][10]​

TimepointResponder rateKey data
6 mo90%UUI 5.6 → 1.3/day; 34-point ICIQ-OABqol improvement; no serious device-related AE
1 yr89%UUI 5.6 → 1.4/day; 100% able to recharge; 96% found recharging acceptable
2 yr93%82% achieved ≥ 75% UUI reduction; 37% completely dry; UUI 5.6 → 1.0/day; 94% found recharging acceptable; no unanticipated or serious device-related AEs

Satisfaction (1 yr): 68.5% "very satisfied," 25.8% "moderately satisfied," 2.4% "slightly satisfied"; correlates with degree of symptom improvement (p < 0.001).[10]

Fecal Incontinence (n = 15)[6]​

  • 87% test responders at 4 wk.
  • Weekly FI episodes 8 → 1.5 (75% reduction at 4 wk, 79% at 6 mo).
  • 92% sustained response at 6 mo; mean recharge time 37 min, once or twice weekly; all moderately or very satisfied.

Rechargeable vs Non-Rechargeable — The Critical Real-World Caveat​

The rechargeable design was intended to reduce reinterventions by eliminating battery replacements. Real-world data complicate that expectation:[11]

  • Rechargeable SNM devices (Axonics + InterStim Micro pooled) had significantly lower revision-free survival than non-rechargeable. By ~1,600 days, revision-free survival was ~64% rechargeable vs ~82% non-rechargeable.
  • Difficulty charging and connecting accounted for over a third of revisions in the rechargeable group.
  • Comparing the two rechargeable manufacturers (Axonics vs Medtronic Micro), there was no significant difference in revision-free survival — this is a class effect of rechargeable systems, not manufacturer-specific.

Discrepancy with trial data: ARTISAN reported 94–96% trial-population recharging acceptability,[7][8] while a real-world InterStim Micro FI cohort reported 62% regret, 96% charging challenges, 86% connectivity issues.[12] Patient selection, training, and the gap between trial and routine practice likely explain the difference.

Cost-Effectiveness​

The theoretical argument: the non-rechargeable InterStim II required replacement every ~5–6 yr (a 50-year-old could otherwise need 3–5 replacements at ~$10,000–15,000 each). A ≥ 15-year rechargeable battery should eliminate most replacements.[1][3]

The real-world adjustment: many revisions are unrelated to battery depletion (lead migration, loss of efficacy, pain, infection, charging / connectivity issues), so a rechargeable system reduces but does not eliminate ongoing maintenance.[3][11]

SNM vs Implantable Tibial Neuromodulation​

Amundsen 2025 SR / meta-analysis comparing SNM (including Axonics) to iTNM:[14]

  • UUI responder rate: SNM 71.8% vs iTNM 71.3%.
  • OAB responder rate: SNM 73.9% vs iTNM 79.4%.
  • Similar device-related AE rates.
  • iTNM achieves comparable efficacy without a trial phase — potentially simplifying the treatment pathway.

Guideline Position​

AUA/SUFU 2024 OAB Guidelines recommend SNM without differentiating between manufacturers:[15]

  • Moderate Recommendation (Grade A) — offer SNM for inadequate response / intolerable side effects from pharmacotherapy or behavioral therapy.
  • Expert Opinion — may offer SNM without requiring prior trials.
  • Clinical Principle — may offer minimally invasive procedures to patients unable or unwilling to undergo behavioral / non-invasive / pharmacologic therapy.

Complications​

Adverse eventARTISAN-SNMRELAX-OABGeneral SNM
Stimulation discomfortMost common device AE20% (resolved with reprogramming)12–22%
Implant site painReportedReported15–28%
Lead migrationReportedReported3–12%
InfectionRare2% (1 explantation)2–10%
Serious device-related AENone at 2 yrNone at 1 yrVariable
Charging-unacceptable (trial)4–6%2%—
Charging-driven revisions (real-world)——> 33% of rechargeable revisions

Single-center SNM cohort: 22% overall revision rate over 18 months; 6.7% explantation. Desire for MRI-compatible device was a revision reason in 7/30 cases — illustrating the practical weight of full-body MRI labeling.[13]

Bottom Line​

Axonics represents a real technological advance — full-body 1.5T/3T MRI and a ≥ 15-yr battery — with excellent trial efficacy (89–93% UUI responders through 2 years) and high reported satisfaction.[1][7][8] The real-world signal is that rechargeable devices as a class (Axonics + InterStim Micro) have lower revision-free survival than non-rechargeable, driven by charging and connectivity difficulties.[11] Device choice should be individualized — MRI need, manual dexterity, technology comfort, and expected longevity all weigh in.

See also: Medtronic InterStim, eCoin, Revi System, Altaviva, PTNS Systems.

References​

1. McCrery R, Lane F, Benson K, et al. Treatment of Urinary Urgency Incontinence Using a Rechargeable SNM System: 6-Month Results of the ARTISAN-SNM Study. The Journal of Urology. 2020;203(1):185-192. doi:10.1097/JU.0000000000000458

2. Wang A, Rourke E, Sebesta E, Dmochowski R. Axonics System for Treatment of Overactive Bladder Syndrome and Urinary Urgency Incontinence. Expert Review of Medical Devices. 2021;18(8):727-732. doi:10.1080/17434440.2021.1947794

3. Cohn JA, Kowalik CG, Kaufman MR, et al. Evaluation of the Axonics Modulation Technologies Sacral Neuromodulation System for the Treatment of Urinary and Fecal Dysfunction. Expert Review of Medical Devices. 2017;14(1):3-14. doi:10.1080/17434440.2017.1268913

4. De Wachter S, Knowles CH, Elterman DS, et al. New Technologies and Applications in Sacral Neuromodulation: An Update. Advances in Therapy. 2020;37(2):637-643. doi:10.1007/s12325-019-01205-z

5. Blok B, Van Kerrebroeck P, de Wachter S, et al. Three Month Clinical Results With a Rechargeable Sacral Neuromodulation System for the Treatment of Overactive Bladder. Neurourology and Urodynamics. 2018;37(S2):S9-S16. doi:10.1002/nau.23465

6. Jottard K, Van den Broeck S, Komen N, Bruyninx L, De Wachter S. Treatment of Fecal Incontinence With a Rechargeable Sacral Neuromodulation System: 6-Month Follow-Up. Neuromodulation. 2021;24(7):1284-1288. doi:10.1111/ner.13298

7. Benson K, McCrery R, Taylor C, et al. One-Year Outcomes of the ARTISAN-SNM Study With the Axonics System for the Treatment of Urinary Urgency Incontinence. Neurourology and Urodynamics. 2020;39(5):1482-1488. doi:10.1002/nau.24376

8. Pezzella A, McCrery R, Lane F, et al. Two-Year Outcomes of the ARTISAN-SNM Study for the Treatment of Urinary Urgency Incontinence Using the Axonics Rechargeable Sacral Neuromodulation System. Neurourology and Urodynamics. 2021;40(2):714-721. doi:10.1002/nau.24615

9. Blok B, Van Kerrebroeck P, de Wachter S, et al. A Prospective, Multicenter Study of a Novel, Miniaturized Rechargeable Sacral Neuromodulation System: 12-Month Results From the RELAX-OAB Study. Neurourology and Urodynamics. 2019;38(2):689-695. doi:10.1002/nau.23892

10. Geynisman-Tan J, Mueller MG, Kenton KS. Satisfaction With a Rechargeable Sacral Neuromodulation System — a Secondary Analysis of the ARTISAN-SNM Study. Neurourology and Urodynamics. 2021;40(1):549-554. doi:10.1002/nau.24596

11. Cohen T, Huang Z, Aalami-Harandi A, et al. Revision Rates for Rechargeable Versus Non-Rechargeable Sacral Neuromodulation Devices in the Management of Overactive Bladder. Neurourology and Urodynamics. 2025;44(5):1031-1035. doi:10.1002/nau.70053

12. Okocha M, La Raja C, Nikolaou S, et al. Outcomes of Rechargeable Sacral Neuromodulation for Faecal Incontinence: A Single-Centre Observational Study. Colorectal Disease. 2025;27(12):e70344. doi:10.1111/codi.70344

13. Nanda R, Chen A, Hernandez N, et al. Factors Contributing to Sacral Neuromodulation Revision: A Single-Center Study. International Urogynecology Journal. 2026;37(3):741-747. doi:10.1007/s00192-025-06376-8

14. Amundsen CL, Sutherland SE, Kielb SJ, Dmochowski RR. Sacral and Implantable Tibial Neuromodulation for the Management of Overactive Bladder: A Systematic Review and Meta-Analysis. Advances in Therapy. 2025;42(1):10-35. doi:10.1007/s12325-024-03019-0

15. Cameron AP, Chung DE, Dielubanza EJ, et al. The AUA/SUFU Guideline on the Diagnosis and Treatment of Idiopathic Overactive Bladder. The Journal of Urology. 2024;212(1):11-20. doi:10.1097/JU.0000000000003985