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Axonics Sacral Neuromodulation Systems

Axonics, now part of Boston Scientific, makes rechargeable and recharge-free sacral neuromodulation (SNM) systems. The InterStim/SNM hub covers broader trial comparisons, neurogenic selection and long-term reintervention.

History​

The original Axonics r-SNM was the first FDA-approved rechargeable SNM system, designed to deliver therapy for at least 15 years.[5] Its design targeted two limitations of earlier non-rechargeable generators. Battery depletion required replacement surgery, and average battery life was about 4.4 years in the historical device.[4][6] Early European experience (RELAX-OAB) preceded the US and European pivotal study (ARTISAN-SNM), and the FDA approved the system in 2019.[5][10][21] Boston Scientific acquired Axonics in 2024. The current F15 and R20 are successors to that first rechargeable generator.

Current Models​

SystemPower and modelManufacturer specification
F15Recharge-free, model 4101; 10 ccProjected 17.6-year battery life at 1 mA, 14 Hz, 210 µs and 1200 Ω[1]; life varies with energy requirements. The Canadian implant manual tabulates 22, 15, 9 and 5 years at 0.5, 1.3, 2.0 and 3.0 mA under those conditions (bipolar, continuous)[18]
R20Rechargeable, model 5101; 5 ccDesigned for 20+ years[1]. The Canadian implant manual lists recharge intervals of 10, 8, 6 and 5 months at 0.1, 1, 1.5 and 2 mA (14 Hz, 210 µs, continuous, 1200 Ω)[19]

R20 is not recharge-free. Older R15/ARTISAN charging schedules do not apply to R20. Neither projected battery life nor a small generator guarantees freedom from revision. Both current systems use constant-current stimulation. The generator, lead and accessories are selected together.[1]

The rationale for a long-lived generator is that a nonrechargeable device requires replacement surgery when the battery is depleted.[4] Revisions unrelated to the battery still occur.[11]

Labeling, MRI and Patient Tasks​

US labeling covers OAB symptoms and urinary retention after inadequate response or intolerance to conservative therapy, plus chronic fecal incontinence after failure of or unsuitability for conservative therapy. It excludes mechanical urinary obstruction. An appropriate test-stimulation response is required, and inability to operate the system is a contraindication.[2]

The fully implanted systems are MR Conditional. Eligibility and scanner limits depend on model, lead configuration and current MRI instructions, and external trial equipment has different restrictions. Full-body 1.5 T and 3 T labeling applies under those conditions. Diathermy is prohibited, and electrosurgery, ablation and other energy procedures need specific precautions.[1][2][3] In one single-center revision series, the wish for an MRI-compatible device was the reason for 7 of 30 revisions.[12]

The patient needs access to the remote and follow-up support, and rechargeable models also require a sustainable charging plan. Neurological-origin urinary dysfunction, pregnancy and pediatric use carry labeling limitations. Device selection accounts for dexterity, cognition, caregiver support, anticipated MRI and the patient's preferences.[2]

Generator Specifications and Implant Technique (Manufacturer Manuals)​

The Canadian-edition implant manuals (both dated May 2025) give the following.[18][19] Confirm against the edition supplied in your own country.

ParameterF15 (model 4101)R20 (model 5101)
Dimensions (height × length × thickness)39 × 53 × 6.7 mm42 × 22 × 6 mm
Weight and volume24.5 g, 10 cc11 g, 5 cc
CaseTitaniumTitanium-ceramic
Radiopaque markerRDPGRJ
Frequency, pulse width, amplitude2 to 50 Hz, 60 to 330 µs, 0 to 8 mA (0.05 mA steps)Same
Ramping, mode0 to 30 s; continuous or cycling; current-controlledSame
Default on delivery14 Hz, 210 µs, 0 mA; electrode 0 negative, electrode 3 positiveSame

Implant points from the manuals:

  • The generator goes in a subcutaneous pocket over the muscle in the upper buttock, no deeper than 3.0 cm and parallel to the skin. A generator that is too deep or tilted can make programming (and, for R20, charging) fail.
  • Place it horizontally. For R20 the ceramic side faces away from the midline. For F15 the lead should enter laterally if its length allows, to avoid kinking.
  • If the patient has another neurostimulator, keep the two at least 20 cm apart.
  • For F15 (model 4101), the Canadian manual specifies pocket irrigation with sterile saline or water; for R20 (model 5101), it specifies antibiotic solution. Both manuals recommend perioperative IV antibiotics and instruct 24 hours of postoperative prophylactic antibiotics. Do not soak the generator in antibiotic solution, which can affect the lead connection, or place it on skin or a non-sterile surface.
  • Dry the connector block and lead before connection. Retract the setscrew without removing it, seat the lead fully (marker D inside the strain relief), and tighten the setscrew on the retention sleeve, not on an electrode, until the torque wrench clicks. The wrench is single use.
  • Do not coil excess lead in front of the generator. Wrap it around the perimeter or place it under the generator so telemetry is not impaired. Check impedances with the generator in the pocket, and anchor it to fascia with non-absorbable silk through the header suture hole (R20 manual).
  • Communication range is about 1 m. Each generator pairs with one remote control. R20 also uses a charger.
  • To replace a generator, preserve the tined lead, back out the setscrew and connect the new unit. Replace any generator that shows damage, pitting or corrosion.

MRI (Canadian patient guidelines): the R15 (model 1101), F15 and R20 generators with tined lead 1201 or 2201 are MR Conditional. The clinician programmer, remote control, charger and external trial equipment are MR Unsafe. With a whole-body transmit coil, the remote-control readiness check must pass and the battery-status light must be green for R15, F15 and R20. If the light is orange on rechargeable R15 or R20, charge the generator before scanning. With detachable head or extremity transmit/receive coils, stimulation is simply switched off. Patients need review first if the generator sits outside the posterior hip or upper buttock, or if they have a broken or disconnected lead or irregular stimulation.[20]

ARTISAN-SNM — Clinical Benefit and Denominators​

ARTISAN was a single-arm prospective study of 129 people with UUI, 98% women, using an earlier rechargeable Axonics system.[6] All participants received the lead and generator in a single nonstaged procedure without a test phase.[6][7] Nine had previously passed an external trial without a full implant; excluding them did not change the responder rates.[5]

Follow-upReported response: at least 50% UUI reductionOther reported data
Six monthsApproximately 90% in the all-implanted analysisUUI episodes per day 5.6 to 1.3; 34-point ICIQ-OABqol improvement; no serious device-related adverse events [6]
One year89% across 129 participantsUUI episodes per day 5.6 to 1.4; all 124 one-year attendees able to recharge; 96% found recharging acceptable [7]
Two years93% of 121 completers, versus 88% of all 129 when missing or exited participants counted as failuresUUI episodes per day 5.6 to 1.0; 94% found recharging acceptable; no unanticipated or serious device-related adverse events [5]

At two years, 82% achieving at least 75% reduction and 37% being dry were percentages of the 113 responders, not all implanted participants.[5] Recharging was acceptable to 94% of the 121 follow-up participants.[5] The study reported 14 surgical interventions in 11 of 129 participants, despite no unanticipated or serious device- or procedure-related adverse events.[5][6][7]

In a secondary analysis of 124 participants with complete one-year data, 68.5% were very satisfied, 25.8% moderately satisfied and 2.4% slightly satisfied. Satisfaction correlated with the degree of symptom improvement. Nine of 14 participants who were nonresponders at one month were responders at one year.[8]

ARTISAN was sponsored by Axonics, which supported its design, data analysis and writing.[5]

RELAX-OAB was a European post-market study in which 51 participants were implanted in a single stage. At three months, 31 of 34 (91%) who had responded during an initial trial period continued to benefit.[9] One participant was explanted for infection, and 19.6% had device-related adverse events, most often stimulation discomfort resolved with reprogramming.[9] At one year, 94% of initial test responders continued to respond.[10] The one-year QoL gain was 21.1 points on ICIQ-OABqol, 84% of initial test responders were very or moderately satisfied and 98% found charging acceptable.[10] Device-related adverse events occurred in 21%, with stimulation discomfort in 20%.[10] The 94% figure applies to initial test responders and not to all 51 implanted.[10]

Fecal Incontinence​

In a prospective series of 15 patients with fecal incontinence implanted in a single stage with the Axonics system, 13 (87%) were test responders at four weeks. Median weekly incontinence episodes fell from 8 to 1.5 at four weeks and 1.5 at six months. Of the 13 four-week responders, 12 were therapy responders at six months. Mean recharge time was 37 minutes once or twice a week, and all patients were moderately or very satisfied. There were no unanticipated device- or procedure-related adverse events.[13]

Rechargeable Versus Recharge-Free​

One retrospective single-center comparison of 246 patients found revisions in 34% of 150 rechargeable recipients versus 13.5% of 96 nonrechargeable recipients (p < 0.001). Difficulty charging accounted for 35.3% of rechargeable revisions.[11]

Trial acceptability of charging (94% to 98% across the Axonics studies) contrasts with a single-center observational cohort of 38 patients who received a rechargeable InterStim Micro for fecal incontinence, 28 (74%) as replacements for nonrechargeable devices.[5][7][10][14] At 24 months or more, 20 of 37 interviewed patients (54%) reported device regret, 75% connectivity problems and 96% device-management difficulty.[14]Device choice should connect expected treatment benefit with the patient's ability to manage the specific system.

The 2025 SNM-versus-implantable-tibial meta-analysis (20 studies, 1,416 SNM and 350 implantable tibial patients) used separate single-arm cohorts and no randomized head-to-head comparison. Weighted UUI responder rates were 71.8% for SNM and 71.3% for implantable tibial neuromodulation, and OAB responder rates were 73.9% and 79.4%. Device-related adverse event rates were similar. The implantable tibial studies did not use a trial phase.[15]

Guideline Position​

The AUA/SUFU 2024 OAB guideline does not distinguish between manufacturers. It states that clinicians should offer sacral neuromodulation, tibial nerve stimulation and/or intradetrusor botulinum toxin injection to patients with an inadequate response to, or intolerable side effects from, pharmacotherapy or behavioral therapy . Clinicians may offer minimally invasive therapies in shared decision-making without requiring prior trials of behavioral, non-invasive or pharmacologic management , and may offer them to patients unable or unwilling to undergo those therapies .[16]

Tined-Lead Insertion Safety Update​

October 2025 notices from Health Canada and the Australian TGA described difficulty advancing some model 1201 tined leads through the introducer sheath, associated with adhesive affecting tine deflection. The notices recommend backup kits and exchange of affected devices. Implanted-lead performance was not affected. The Australian correction was closed in January 2026. If resistance is encountered, check current local manufacturer instructions. Do not force advancement or assume an implanted lead needs removal.[17]

For test placement and operative technique, see Sacral Neuromodulation. For other device options, see PTNS systems, eCoin, Revi and Altaviva.

References​

1. Boston Scientific. Axonics Sacral Neuromodulation System. Current US F15/R20 specifications and model numbers. Product resource.

2. Axonics/Boston Scientific. Important Safety Information — United States/Canada. Current manufacturer summary. Indications, contraindications and precautions.

3. Axonics/Boston Scientific. Current manuals library. Select the actual model, country and current MRI physician guidelines. Manufacturer manuals.

4. Cohn JA, Kowalik CG, Kaufman MR, Reynolds WS, Milam DF, Dmochowski RR. 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

5. 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

6. 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

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. 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

9. 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

10. 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

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. 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

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

14. 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

15. 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

16. 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

17. Health Canada. Axonics SNM System — Tined Lead, model 1201. October 22, 2025, RA-78345; Australian TGA product correction RC-2025-RN-00854-1. Health Canada; TGA action and handling instructions.

18. Axonics. Neurostimulator Implant Manual, Recharge-Free, Model 4101 (F15), Canada. Document 110-0230-201 Rev D, May 2025, Table 1, Table 2 and implant procedure.

19. Axonics. Neurostimulator Implant Manual, Rechargeable, Model 5101 (R20), Canada. Document 110-0290-201 Rev C, May 2025, Tables 1 and 2 and implant procedure.

20. Axonics. MRI Patient Guidelines for the Axonics SNM Systems, Canada. Document 110-0093-201 Rev A, 2024, sections 2, 3 and 5.

21. US Food and Drug Administration. Axonics Sacral Neuromodulation System: original urinary-indication approval, PMA P180046. November 13, 2019. FDA PMA record.