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Implantable Tibial Nerve Stimulation (iTNM)

Implantable tibial nerve stimulation (iTNM) targets the posterior tibial nerve through a lower-leg implant rather than repeated office PTNS. The at-home maintenance model differs by device: eCoin stimulates automatically, Revi requires an external wearable, and Medtronic Altaviva is rechargeable. These devices avoid routine in-office PTNS induction and maintenance visits but require implantation, system-specific precautions and follow-up.[1][18][19][20]

See the PTNS page for the underlying neuromodulation rationale and the SUmiT pivotal sham-controlled foundation.

Rationale for Implantable Devices​

The primary limitations of PTNS (the burden of weekly in-office visits, short-lived effects requiring indefinite maintenance, and limited insurance coverage) have driven the development of implantable alternatives. Real-world data show that over 40% of PTNS maintenance patients discontinue therapy due to logistic reasons and physical strain rather than treatment failure.[2] Implantable devices address these barriers by providing continuous or scheduled at-home stimulation through a permanent implant, with the added potential for dynamic, patient-centered programming.[1]

Implantable Tibial Nerve Stimulation Systems​

eCoin® (Valencia Technologies)​

The eCoin is a nickel-sized, coin-shaped, fully implanted, primary battery-powered device placed in the lower leg above the fascia over the tibial nerve. It delivers automated, pre-programmed, low-duty-cycle stimulation without requiring any external wearable for daily therapy.[3][4]

  • Implantation: Performed under local anesthesia in approximately 20 minutes; placed suprafascially over the tibial nerve in the lower leg and activated 4 weeks post-implantation.[5][6]
  • Power source: Internal primary (non-rechargeable) battery
  • Stimulation: Automatic, intermittent low-duty cycle; no patient interaction required for daily therapy delivery[4]
  • FDA status: PMA-approved for UUI after intolerance of or inadequate response to more conservative treatments, or after a successful PTNS trial.[18]

Revi® (BlueWind Medical, formerly RENOVA™)​

The Revi is a leadless, miniature, battery-free implant placed subfascially near the tibial nerve. It is powered wirelessly by an external, battery-operated lower-leg wearable (worn in a leg band over the implant site) that the patient controls, allowing individually tailored stimulation parameters.[8][9]

  • Implantation: Subfascial placement near the tibial nerve; median operative time approximately 34 minutes in early studies[10]
  • Power source: Battery-free implant; powered externally by a wearable leg-band device
  • Stimulation: Patient-controlled via the external wearable, enabling personalized therapy sessions at home[9][11]
  • FDA status: FDA-cleared Revi labeling is for urgency incontinence alone or with urinary urgency, without an explicit prior-conservative-treatment failure condition.[19]

Revi implantation (manufacturer technique). The US surgical technique guide describes the following steps. A BlueWind representative runs a system self-test on the clinician programmer before the implant pouch is opened.[24]

  1. Administer prophylactic IV antibiotics 15 to 60 minutes before skin incision. Infiltrate local anesthetic along the marked incision line above the medial malleolus, avoiding injection beneath the fascia; general or regional anesthesia may be added if needed. Prepare the skin with chlorhexidine and drape the foot tightly.[24]
  2. Make a 5 cm incision and dissect bluntly through fat to the crural fascia. Cutting-mode electrocautery is not used at any stage, and no electrocautery is used once the crural fascia is exposed.
  3. Divide the crural fascia with a guarded technique and identify the posterior tibial neurovascular bundle. If a second fascial layer or muscle obscures it, count two tendons posterior to the tibia (tibialis posterior and flexor digitorum longus), or extend the incision distally, where the bundle is more superficial.
  4. Hold the implant by its silicone membrane with plastic or anatomical forceps, because sharp objects, including tissue forceps, can damage its Parylene coating. Place it over the neurovascular bundle with the larger electrode distal and the smooth silicone surface superficial, parallel to the skin and no deeper than 3 cm, or energy transfer may fail.
  5. Test stimulation through the wearable in a sterile sleeve. Paresthesia or a motor response (great-toe flexion or fanning of the toes) at a low or moderate amplitude (below 5 mA) is optimal; testing at the treatment frequency is recommended, but a low frequency (4 Hz) makes the motor response easier to see and is recommended under general or regional anesthesia. Reposition the implant closer to the nerve if the response is unsatisfactory.
  6. Anchor the implant to the fascia with nonabsorbable suture (such as 3-0 polypropylene or polyester) and retest. Leave the fascial incision open. Close the subcutaneous layer with absorbable braided suture and the skin with interrupted nylon or an intradermal absorbable monofilament, retest, and apply a compressive dressing.

The guide calls for antibiotics and analgesics for the first 24 hours, leg elevation for the first 3 days, suture removal at 10 to 14 days and the first treatment setup after the wound has healed, at least 2 weeks after surgery; OASIS activated the device 4 weeks (±2 weeks) after implantation. The guide recommends against explantation without a specific medical need or the treating clinician's judgment that it is necessary.[24]

Altaviva™ (Medtronic, formerly investigational ITNM)​

Altaviva is a rechargeable, implanted tibial stimulator. Its TITAN 2 trial appears below.[21] The FDA approved Altaviva in September 2025 for UUI in patients who failed or could not tolerate more conservative treatments.[21]

Protect PNS (Uro Medical Corp.) and Others​

A percutaneous implantable pulse generator (pIPG) with integrated quadripolar electrodes has been studied in a pilot trial. It is implanted in the office under local anesthesia using a retrograde approach and activated via an external wireless transmitter. In a pilot of seven implant recipients, office implantation under local anesthesia was feasible without reported procedure-related complications, but two older-model devices became nonresponsive at 1 and 4 weeks and were replaced; six minor adverse events resolved, and larger comparative studies are needed.[12]

The investigational Intibia system was described in a first-in-human feasibility study of 10 patients (7 OAB-wet and 3 OAB-dry).[13] After 2 weeks of daily stimulation followed by 13 weeks of weekly stimulation, 8 of 10 had at least 50% improvement in one or more OAB components; no serious adverse events were reported.[13]

Clinical Evidence Summary​

DeviceStudyNFollow-up≥50% UUI reductionKey safety findings
eCoinFeasibility[5][6]4612 mo65%; 26% dry1 SAE (wound care, resolved)
eCoinPivotal FDA ITT[18]13348 wk of stimulation68%Device-related harms require review of the FDA event tables; no cross-device rate inference
eCoinPivotal extension[7][25]72 completed; 69 with UUI data96 wk78%; 22% dryNo serious or unanticipated AEs
ReviOASIS pivotal, ITT[24]1516 mo76.4%No device / procedure-related SAEs
ReviOASIS 2-year[9]97 with 24-mo diaries24 mo77/97 (79%)No device- or procedure-related SAEs; 88/91 (97%) of survey respondents satisfied; 3/151 (2%) explanted by 24 mo
ReviOASIS 3-year[8]9036 mo79%No device / procedure-related SAEs; 83/87 survey respondents (95%) satisfied
Altaviva (Medtronic ITNM)TITAN 2 pivotal[14][21]12612 mo (post hoc)61%25/126 (20%) related AEs; publication counted 1 resolved serious event, and FDA classified implant wound infection requiring explantation as a second serious event

These device studies were single-arm cohorts with different endpoints. The 96-week eCoin and 36-month Revi follow-up cohorts were smaller than the pivotal cohorts.[7][8][18]

Key Pivotal Trials​

OASIS Study (Revi)​

The pivotal OASIS trial enrolled 151 women with UUI. The primary endpoint, ≥50% reduction in UUI episodes 6 months after activation, was met by 76.4% (95% CI 68.7% to 82.6%) in the intention-to-treat analysis; a post hoc 12-month post-activation ITT analysis gave 78.4%.[24][27] The two-year report gives 78% at 6 months among participants with diaries, and 79% of the 90 participants with 36-month diaries were responders.[8][9] Quality-of-life improvements were clinically significant across all OAB-q domains. At 3 years, 83 of 87 survey respondents (95%) reported therapeutic satisfaction, and 74 of 90 participants (82%) reported feeling "much better" or "very much better".[8] No device- or procedure-related serious adverse events occurred through 36 months.[8][9][11]

eCoin Pivotal Trial​

The FDA pivotal study included 133 implanted or attempted-implant participants in the ITT population, with 68% achieving ≥50% reduction in UUI episodes after 48 weeks of stimulation.[18] A smaller observed extension cohort reported 78% responders and 22% dry at 96 weeks; its denominator and uncontrolled design limit comparison with the pivotal cohort.[7]

TITAN 2 (Medtronic ITNM)​

This pivotal IDE study enrolled 126 subjects implanted with the Medtronic leadless, rechargeable ITNM system. At 6 months, 59% achieved ≥50% improvement in UUI episodes/day (primary endpoint met, p < 0.001 versus performance goal).[14] In a post hoc, multiply imputed 12-month FDA subgroup analysis, 46.9% of 68 participants aged 65 years or older and 76.4% of 58 younger participants met the UUI responder threshold; FDA required age-specific postapproval follow-up.[21] The trial publication reported adverse device effects in 20% and one resolved serious C. difficile event.[14][21] FDA counted related events in 25/126 (20%) and also classified an implant wound infection requiring explantation as serious.[14][21]

Comparison with Sacral Neuromodulation (SNM)​

A systematic review of separate iTNM and SNM studies (20 studies, 1,766 patients) reported pooled UUI responder proportions of 71.3% and 71.8%, respectively. The studied tibial implants generally did not use an SNM-style temporary test phase.[15]

Safety Profile​

Safety and MRI conditions are device-specific:

  • eCoin: The original FDA physician labeling contraindicates implantation in specified poor lower-leg surgical candidates (including open wound, local vascular disease/edema and local infection) and patients unable to operate the magnet controller if unwanted stimulation occurs.[18] The implant is MR conditional only under its labeled conditions, including keeping it at least 20 cm outside the MRI bore at 1.5/3 T; the controller magnet is MR unsafe.[18] Diathermy is prohibited. The patient manual also lists prior surgery in the implant area and lower-leg venous or arterial disease as contraindications, gives stimulation as 30-minute sessions every 3 days for 18 weeks and every 4 days afterward, and states battery life of 3 to 5 years at the nominal 6 mA setting.[23] Confirm any later PMA supplement or label revision.[18][23]
  • Revi: The manufacturer lists inability to operate the system, men with obstructive BPH or other lower urinary tract obstruction, metallic implants within about 20 cm (8 in) of the implant site, nerve damage affecting treatment, implant-material allergy, high surgical risk or multiple illnesses or active general infections associated with excessive bleeding or delayed or nonhealing wounds, prior surgery or unhealed trauma at the implant site, lower-leg wound-healing risks (open wounds, edema, venous or arterial disease) and pregnancy among contraindications. The implant is MR Conditional at 1.5 T or 3.0 T (scanning at lower field strengths is also permitted) with a maximum spatial gradient of 30 T/m and maximum slew rate of 200 T/m/s, plus SAR and scan-duration limits that depend on the body region scanned. All external components and accessories are MR Unsafe and stay out of the scanner room. Shortwave, microwave and ultrasound diathermy are prohibited anywhere on or near the body because energy transfer can cause severe injury or implant damage. Full current model labeling governs screening and scanning.[20]
  • Altaviva: FDA's original PMA label limits the indication to UUI after failure or intolerance of conservative therapies; FDA's contraindications are skin lesions or compromised skin integrity, current or recent venous insufficiency or venous stasis ulcers in the lower leg, anatomic defects or prior surgery at the implant site that preclude use, and inability to operate the system or receive help operating it. The leadless rechargeable neurostimulator sits in a deep-fascia pocket superior to the medial malleolus and anterior to the Achilles tendon. Non-clinical testing supports MRI at 1.5 T and 3 T only under labeled conditions.[21] The FDA patient guide says patients should not have shortwave or microwave diathermy and warns that recharging within 5 cm of another below-knee metal implant in the same leg may cause tissue injury requiring surgery.[21]

Observed study harms (different denominators and ascertainment):

  • eCoin: Most adverse events relate to wound healing and infection at the implant site. In the pivotal trial, 16% experienced device-related events through 52 weeks, mostly minor.[3][4] The patient manual counts 23 of 133 (17%) with device-related events.[23] The FDA labeling reports device- or procedure-related events in 27 of 133 implanted patients (20%) through 52 weeks; 25 had nonserious and 4 had serious related events, with 2 participants counted in both groups.[18] Three of the four serious related events were infections and one was contact dermatitis, all resulting in explantation. Four additional devices were explanted by 52 weeks: three for MRI needs and one for device failure; one device was revised for dislocation.[18] No serious or unanticipated AEs were reported in the 2-year extension.[7][18]
  • Revi: No device- or procedure-related serious adverse events through 3 years of follow-up in the OASIS study.[8] The earlier 36-patient feasibility study reported implant site pain (14%), suspected infection (22%) and procedural wound complications (8%); one system was removed for inflammation.[16]
  • Medtronic ITNM: In TITAN 2, 25/126 (20%) had related adverse events through 12 months; the publication counted one resolved serious event, while FDA also classified an implant wound infection requiring explantation as serious.[14][21] FDA reported three device explants before the 12-month visit.[14][21]

Advantages Over PTNS​

  • Avoids repeated in-office PTNS treatment visits. At-home therapy delivery[1]
  • Maintenance burden. Home-based stimulation avoids office PTNS maintenance visits, a barrier reported in a retrospective PTNS cohort.[1][2]
  • Longer observed follow-up. Selected eCoin and Revi cohorts report responses through 2–3 years; lack of a randomized PTNS comparator prevents concluding that implants eliminate wearing-off or are more durable[7][8]
  • Patient-controlled therapy (Revi) allows individualized stimulation parameters[9]
  • No SNM-style temporary test phase in the studied implant pathways. Confirm the individual device's indication and preimplant evaluation; eCoin labeling also allows eligibility after a successful PTNS trial[15][18]

Guideline Positioning​

The AUA/SUFU 2024 guideline lists implantable tibial nerve stimulation among the minimally invasive OAB therapies (Table 3), but its named recommendation for patients with inadequate response to or intolerance of drugs or behavioral therapy covers sacral neuromodulation, percutaneous tibial nerve stimulation and intradetrusor onabotulinumtoxinA rather than implantable devices, because the panel found no direct comparison or placebo-controlled data for the implantable systems (its review cites single-arm studies of 137 patients for eCoin, with 68% achieving a ≥50% UUI reduction at 48 weeks, and 36 patients for Revi).[17] AUA/SUFU Statement 24 permits minimally invasive therapy without prior behavioral, noninvasive or drug trials through shared decision-making ; its named treatment offer in Statement 25 is a Moderate Recommendation (Grade A).[17] The EAU 2026 female LUTS guideline recommends offering percutaneous or transcutaneous posterior tibial nerve stimulation as an option for OAB/UUI but makes no statement on implanted tibial systems.[22]

Limitations and Considerations​

  • The pivotal eCoin, Revi and Altaviva efficacy studies cited above were single-arm and open-label.[4][9][14] Sham-controlled PTNS trials support tibial stimulation as therapy.[1] In a randomized sham-controlled Intibia trial of 208 implanted, predominantly female participants (139 active, 69 sham), more active-treatment participants exceeded the OABq-SF symptom-bother minimally important difference at 3 months (62.8% versus 41.8%, p = 0.0046); this planned secondary quality-of-life report did not present the primary UUI responder comparison.[26]
  • No head-to-head randomized trials comparing iTNM devices to each other, to SNM, or to onabotulinumtoxinA[15]
  • Long-term data beyond 3 years remain limited
  • The eCoin uses a non-rechargeable primary battery, raising questions about device longevity and potential need for replacement
  • MRI compatibility varies by device and should be confirmed before implantation
  • Cost-effectiveness data are still emerging

See Also​

Podcasts​

Exploring Neuromodulation: Sacral vs Tibial Approaches
BackTable Urology, Ep. 318 (2026) · Tracey Wilson, Kenneth Peters
backtable.com

Videos​

Implantable Tibial Nerve Stimulators for Advanced OAB
Dr. Christopher Smith, Grand Rounds in Urology (2025)
Tier 3 OAB Treatment with eCoin
Dr. Jason Kim, Grand Rounds in Urology (2025)

References​

1. Lee UJ, MacDiarmid S, Matthews CA, Gillespie E, Peters KM. "Tibial Nerve Stimulation for Urge Urinary Incontinence and Overactive Bladder: Narrative Review of Randomized Controlled Trials and Applicability to Implantable Devices." Adv Ther. 2024;41(7):2635-2654. doi:10.1007/s12325-024-02864-3

2. Te Dorsthorst MJ, Heesakkers JPFA, van Balken MR. "Long-Term Real-Life Adherence of Percutaneous Tibial Nerve Stimulation in Over 400 Patients." Neurourol Urodyn. 2020;39(2):702-706. doi:10.1002/nau.24254

3. Bressington MJ, Scholtz D, Hooshiary A, et al. "Device Evaluation: eCoin — Implantable Tibial Nerve Stimulator for Overactive Bladder." Expert Rev Med Devices. 2023;20(11):899-904. doi:10.1080/17434440.2023.2254678

4. Rogers A, Bragg S, Ferrante K, Thenuwara C, Peterson DKL. "Pivotal Study of Leadless Tibial Nerve Stimulation With eCoin® for Urgency Urinary Incontinence: An Open-Label, Single Arm Trial." J Urol. 2021;206(2):399-408. doi:10.1097/JU.0000000000001733

5. Gilling P, Meffan P, Kaaki B, et al. "Twelve-Month Durability of a Fully-Implanted, Nickel-Sized and Shaped Tibial Nerve Stimulator for the Treatment of Overactive Bladder Syndrome With Urgency Urinary Incontinence: A Single-Arm, Prospective Study." Urology. 2021;157:71-78. doi:10.1016/j.urology.2021.04.039

6. MacDiarmid S, Staskin DR, Lucente V, et al. "Feasibility of a Fully Implanted, Nickel Sized and Shaped Tibial Nerve Stimulator for the Treatment of Overactive Bladder Syndrome With Urgency Urinary Incontinence." J Urol. 2019;201(5):967-972. doi:10.1016/j.juro.2018.10.017

7. Lucente V, Giusto L, MacDiarmid S. "Two-Year Pivotal Study Analysis of the Safety and Efficacy of Implantable Tibial Nerve Stimulation With eCoin® for Urgency Urinary Incontinence." Urology. 2024;194:17-23. doi:10.1016/j.urology.2024.07.046

8. Amundsen CL, Sutherland SE, Heesakkers JPFA, et al. "Three-Year Efficacy and Safety of Revi® Implantable Tibial Neuromodulation From the Pivotal OASIS Study." J Urol. 2026. doi:10.1097/JU.0000000000005062

9. Heesakkers JPFA, Toozs-Hobson P, Sutherland SE, et al. "Two-Year Efficacy and Safety Outcomes of the Pivotal OASIS Study Using the Revi System for Treatment of Urgency Urinary Incontinence." J Urol. 2025;213(3):323-332. doi:10.1097/JU.0000000000004328

10. van Breda HMK, Martens FMJ, Tromp J, Heesakkers JPFA. "A New Implanted Posterior Tibial Nerve Stimulator for the Treatment of Overactive Bladder Syndrome: 3-Month Results of a Novel Therapy at a Single Center." J Urol. 2017;198(1):205-210. doi:10.1016/j.juro.2017.01.078

11. Sutherland SE, Heesakkers JPFA, Ferrante KL, Dmochowski RR. "Impact of Revi® Implantable Tibial Neuromodulation on Quality of Life in Patients With Urgency Urinary Incontinence." Int Urogynecol J. 2026. doi:10.1007/s00192-026-06538-2

12. Sirls LT, Schonhoff A, Waldvogel A, Peters KM. "Development of an Implant Technique and Early Experience Using a Novel Implantable Pulse Generator With a Quadripolar Electrode Array at the Tibial Nerve for Refractory Overactive Bladder." Neurourol Urodyn. 2023;42(2):427-435. doi:10.1002/nau.25117

13. Sethi PS, Peters KM. "A First-in-Human Feasibility Study of a New Implantable Tibial Nerve Stimulator for Overactive Bladder Syndrome." Neuromodulation. 2025;28(5):832-839. doi:10.1016/j.neurom.2025.01.013

14. Lee U, Xavier K, Carey J, et al. "Implantable Tibial Neuromodulation Therapy Improves Symptoms of Urge Urinary Incontinence From the TITAN 2 Pivotal Study." J Urol. 2026. doi:10.1097/JU.0000000000004958

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." Adv Ther. 2025;42(1):10-35. doi:10.1007/s12325-024-03019-0

16. Heesakkers JPFA, Digesu GA, van Breda J, Van Kerrebroeck P, Elneil S. "A Novel Leadless, Miniature Implantable Tibial Nerve Neuromodulation System for the Management of Overactive Bladder Complaints." Neurourol Urodyn. 2018;37(3):1060-1067. doi:10.1002/nau.23401

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

18. US Food and Drug Administration. eCoin Peripheral Neurostimulator, Physician Labeling, P200036D, document 903-1225 Rev PB, pp.11-15 and pivotal study Tables 5-8. FDA physician labeling.

19. US Food and Drug Administration. Revi System, 510(k) K240037, indications and summary. FDA clearance.

20. BlueWind Medical. Revi System Important Safety Information, manufacturer online labeling (accessed September 2026). Indications, contraindications and MRI conditions.

21. US Food and Drug Administration. Medtronic Altaviva System, PMA P240011, original approval 18 September 2025 and supplement register. FDA approval record.

22. European Association of Urology. EAU Guidelines on Management of Non-Neurogenic Female Lower Urinary Tract Symptoms (LUTS) (2026 reprint of the 2025 guideline). Guideline.

23. Valencia Technologies. eCoin Peripheral Neurostimulator System Patient Manual. Document 903-1236 Rev PB, 2020 (FDA P200036C).

24. BlueWind Medical. Revi Surgical Technique Guide, US edition, G02-CLU-0131 Rev 03 (2023). Implantation procedure, patient instructions and summary of clinical evaluation. Filed with the FCC as an exhibit for FCC ID 2BAXD-E02-0.

25. ClinicalTrials.gov. "Pivotal Study of eCoin for Overactive Bladder With Urgency Urinary Incontinence (NCT03556891)." Study Results, 96-week UUI responder outcome. ClinicalTrials.gov

26. Mangel J, Miller K, Erickson T, Dieter A, Roovers JP, Matthews CA. "Randomized, Sham-Controlled, Double-Blind Trial of the Intibia System in Urge Urinary Incontinence: Quality-of-Life Outcomes." Int Urogynecol J. 2026. doi:10.1007/s00192-026-06636-1

27. Heesakkers JPFA, Toozs-Hobson P, Sutherland SE, et al. "A prospective study to assess the effectiveness and safety of the BlueWind System in the treatment of patients diagnosed with urgency urinary incontinence." Neurourol Urodyn. 2024;43(7):1491-1503. doi:10.1002/nau.25477