OASIS (Revi): Implantable Tibial Neuromodulation for Urgency Urinary Incontinence
OASIS (Overactive blAdder StimulatIon System) was a prospective, multicenter, single-arm, open-label pivotal study of the Revi implantable tibial neuromodulation system in 151 implanted women with urgency urinary incontinence (UUI) and an inadequate response to conservative treatment and drugs, with the proportion achieving at least a 50% reduction in UUI episodes at 6 months as the primary endpoint. In the intention-to-treat analysis 76.4% were responders against a 50% performance goal, and no serious adverse event was attributed to the device or the procedure.[1]
- Design and population
- Prospective, multicenter, single-arm, open-label pivotal device study. 151 implanted women (282 consented) at 23 US and European centers with urgency urinary incontinence (at least nine episodes in a 7-day diary) and an inadequate response to conservative treatment and drugs.
- Arms
- Revi implantable tibial neuromodulation system with an external ankle wearable
- Report and follow-up
- 2024 · 6 and 12 months after activation; primary efficacy at 6 months, primary safety from implantation to 12 months
| Endpoint | Results | Effect | Finding |
|---|---|---|---|
| Proportion with at least 50% fewer urgency-related incontinence episodes on a 7-day diary at 6 months after activation; intention-to-treat, imputed for 7 participants with missing 6-month data; performance goal 50% | 76.4% | P <0.0001 | Met |
| Proportion with at least 10 points improvement in OAB-q health-related quality of life at 6 months; intention-to-treat; performance goal 50% | 83.6% | P <0.0001 | Met |
| Proportion with at least 50% fewer urgency-related incontinence episodes or at least 50% fewer large (severe) episodes at 12 months; intention-to-treat; performance goal 50% | 88.0% | P <0.0001 | Met |
| Among participants with at least 8 voids/day and at least 9 urgent episodes at baseline (n=113), proportion with at least 50% fewer PPIUS degree 3-4 urgent episodes or fewer than 8 voids/day at 6 months; intention-to-treat | 74.0% | P <0.0001 | Met |
| Mean urgency-related incontinence episodes per day at baseline, 6 months and 12 months, observed data | 4.8 at baseline; 1.4 at 6 months (n=144); 1.2 at 12 months (n=139) | — | Descriptive |
| Participants with no leakage on at least 3 consecutive diary days at 12 months | 69/139 (50%) | — | Descriptive |
| Symptoms better, much better or very much better at 12 months | 130/139 (93.5%) | — | Descriptive |
Harms: Any adverse event, implantation to 12 months: 285 events in 117/151 participants (77.5%); Serious adverse events: 15 events in 13/151 participants (8.6%); none related to the procedure or device; Device-related adverse events: 6 events in 6/151 participants (4.0%)
Design
Eligible women had at least nine UUI episodes in a 7-day diary and an inadequate response to conservative treatment (dietary and fluid restriction, bladder training, behavioral modification, pelvic floor training, biofeedback) and to pharmacologic treatment; women with systemic progressive neurologic disease, neurogenic bladder or predominant stress incontinence were excluded. Twenty-three sites in the United States and Europe took part; 87 of the 151 implanted women (58%) were treated in the United States and 64 (42%) in Europe. Nearly all had taken OAB medication (150 of 151), 123 (81.5%) an antimuscarinic and 71 (47.0%) a beta-3 agonist; 18 (11.9%) had received botulinum toxin injections and 29 (19.2%) percutaneous tibial nerve stimulation (PTNS); 97 (64.2%) had been diagnosed more than 5 years earlier. Stable OAB medication was permitted.[1]
Investigators had experience with sacral neuromodulation (SNM) and PTNS, and completed didactic sessions with cadaveric training or proctoring for their first implantations. An independent clinical events committee adjudicated adverse events for severity, seriousness and relatedness through 12 months.[1]
The primary efficacy endpoint was the proportion of intention-to-treat participants with at least a 50% reduction in average urgency-related incontinence episodes (7-day diary) at 6 months after activation, tested against a 50% performance goal; the null was rejected if the lower bound of a two-sided 95% Clopper-Pearson interval exceeded 50%. The primary safety endpoint was the incidence of adverse events from implantation to 12 months after activation. Three secondary endpoints were tested in a modified Hochberg step-up procedure only after the primary null was rejected: at least 10 points of improvement in OAB-q health-related quality of life at 6 months, at least a 50% reduction in UUI or large (severe) UUI episodes at 12 months, and a composite of urgency episodes and voids at 6 months in participants with at least 8 voids per day and 9 urgent episodes at baseline. Other endpoints were descriptive.[1]
The intention-to-treat population was every participant in whom an implant was attempted; there is no test phase before implantation. Missing data were imputed for 7 participants at 6 months and 12 at 12 months, and one participant explanted before the 9-month visit counted as a failure.[1]
Results
At 6 months, 76.4% of the intention-to-treat population were responders (P < 0.0001 against the 50% goal), and the primary endpoint was met. The FDA De Novo summary reports a 95% confidence interval of 68.7% to 82.6%, with a lower bound above the 50% goal.[1][2] At 12 months the intention-to-treat rate was 78.4%, an analysis that the FDA summary classifies as post hoc.[1][2] Among the 139 participants with a completed 12-month diary, 82% were responders; of those with 6- and 12-month diaries, 100 of 110 (91%) 6-month responders were still responders at 12 months, and 48% of 6-month nonresponders had become responders.[1] Mean UUI episodes fell from 4.8 per day at baseline to 1.4 at 6 months (n = 144) and 1.2 at 12 months (n = 139), and 69 of 139 (50%) were dry on at least 3 consecutive diary days at 12 months.[1]
All three type I error-controlled secondary endpoints were met against their performance goals: 83.6% had at least a 10-point improvement in OAB-q health-related quality of life at 6 months, 88.0% had at least a 50% reduction in UUI or large UUI episodes at 12 months, and 74.0% of the 113 eligible participants met the urgency and frequency composite at 6 months.[1] At 12 months 130 of 139 (93.5%) rated their symptoms better, much better or very much better on the Patient Global Impression of Improvement.[1] In an exploratory comparison, 23 of 29 (79.3%) women with prior PTNS and 89 of 114 (78.1%) without it were responders; prior PTNS was not an entry requirement.[1]
The 24-month report followed participants who consented to an extension study. Among the 97 with 24-month diaries, 77 (79%) were responders and 54 (56%) had at least a 75% reduction in UUI; response rates among participants with data were 78%, 82% and 79% at 6, 12 and 24 months. UUI leaks fell from 4.5 to 1.3 per day, 27 of 97 (28%) were dry, 88 of 91 survey respondents (97%) were satisfied, and 94 of 97 (96.9%) rated themselves better to very much better. A last-observation-carried-forward analysis of all implanted participants gave a responder rate of 69.5%, and 136 of 149 participants (91%) with a follow-up visit had at least a 50% reduction at one or more visits.[3]
At 36 months, 71 of 90 participants (79%) with diaries were responders, 57 of 90 (63%) had at least a 75% reduction, 25 of 90 (28%) were dry on a 3-day diary and UUI leaks had fallen from 4.8 to 1.2 per day. Of those answering the satisfaction questionnaire, 83 of 87 (95%) were satisfied and 85 of 87 (98%) would continue treatment; 74 of 90 (82%) rated themselves much better or very much better.[4] A quality-of-life analysis through 24 months found that 87.2% of 94 completers had at least a 10-point improvement in total HRQL, and among the 20 participants below the responder threshold at 24 months, 15 of 18 questionnaire completers reported benefit, 12 of 18 satisfaction and all 18 willingness to continue; their mean reduction in UUI episodes was 20.3%.[5]
Surgery and treatment delivery
The implant was placed in an operating room through an incision of about 5 cm immediately above the ankle. It lies subfascially against the posterior tibial neurovascular bundle on the medial ankle; stimulation was raised during intraoperative testing until the patient reported paresthesia in the heel, sole or toe, and the implant was then sutured to the crural fascia. Local anesthesia was used in 134 of 151 participants (88.7%), the rest had other anesthesia such as monitored sedation, and none had regional or general anesthesia. The left leg was used in 102 (67.5%). [1][4]
Activation followed within 4 (plus or minus 2) weeks of implantation. The external wearable is worn around the ankle over the implant and transmits energy by magnetic coupling. Settings were programmed with a clinician tablet, and patients could switch between two programs. Default settings at activation were 14 Hz and 210 microseconds, within ranges of 2 to 30 Hz, 190 to 790 microseconds and 0.2 to 10 mA. Participants used the wearable for about 30 to 60 minutes and no more than 120 minutes a day, with at least one daily treatment in more than 90% at every visit in year 1.[1] After 12 months the protocol required at least two 30-minute sessions per week; at 36 months 69 of 90 (77%) still used it at least daily and 21 of 90 (23%) used it less than daily by choice.[3][4]
Adverse events
Through 12 months, 285 adverse events occurred in 117 of 151 participants (77.5%), most of them unrelated to the device or procedure. Fifteen serious adverse events occurred in 13 participants (8.6%), none classified as related. Six device-related events in 6 participants (4.0%) were all pain with stimulation or at the implant. Sixteen procedure-related events in 16 participants (10.6%) included 10 wound-related events (6.6%: 7 wound complications, 2 infections, 1 dehiscence), with onset a mean of 19.0 days after implantation and resolution a mean of 28.9 days later without sequelae, and single cases of numbness, swollen foot, pain, rash, cellulitis and allergic reaction to preoperative medication. All were mild or moderate.[1]
Beyond 12 months, one delayed superficial skin infection from an exuded nonabsorbable braided suture was managed without explantation.[3] Through 36 months there were 12 device-related events in 11 participants (7.3%), mainly pain, discomfort, burning or a stimulation problem, and 19 surgical wound-related events in 13 (8.6%); none was serious, and no device migration or revision procedure occurred.[4] Explants totaled 3 of 151 (2%) at 24 months, none caused by a device- or procedure-related adverse event: a pacemaker requirement, musculoskeletal complications after an unrelated fall, and one at a nonresponder's request in year 2.[3] The 36-month report counts 5 of 151 (3%): two in the first 12 months, two for painful stimulation at 753 and 1,230 days and one for foot fusion surgery at 1,233 days; the two reports give different reasons for the explant after the first year.[4]
Limitations
The study was unblinded and nonrandomized, with no control or sham group, because participants feel the stimulation and intraoperative testing is required for placement; the authors state that within-subject change may include some placebo effect.[1] The extension beyond 12 months was added after some participants had exited, so 97 of 151 (64%) contributed 24-month diaries and 90 of 151 (60%) 36-month diaries, with 3-day instead of 7-day diaries at most visits; the authors' last-observation-carried-forward responder rate of 69.5% is the sensitivity analysis for that loss.[3][4] Only women were enrolled, all with an inadequate response to prior treatment.[1] BlueWind Medical funded the study, and six authors were paid consultants to the sponsor.[1]
In conversation
- Parallel to ARTISAN-SNM (2019). Single-arm pivotal study of a newer implanted neuromodulator for urgency incontinence, sacral rather than tibial, judged against a 50% responder goal.
The OASIS authors place the 6- and 12-month intention-to-treat rates beside sacral neuromodulation results reported with other analysis populations (intention-to-treat, as-treated, completers) and note that most SNM publications exclude patients who fail the test phase, whereas OASIS had no test phase and counted every attempted implant.[1] OASIS had no comparator arm, so these comparisons rest on separate studies.
Guidelines and approvals
- FDA De Novo (DEN220073), decision August 16, 2023. The Revi System was classified as a Class II implanted tibial electrical urinary continence device (21 CFR 876.5305) and is indicated for patients with symptoms of urgency incontinence alone or in combination with urinary urgency. Men with benign prostatic hyperplasia or other lower urinary tract obstruction, and pregnant patients, are contraindicated. The precaution states that physicians should follow current clinical guidelines and use discretion on whether a patient should first fail or not tolerate more conservative treatments. FDA noted that the 10.0 to 8.3 voids per day reduction at 12 months does not support a frequency indication.[2]
Report history
| Published | Report | Cutoff | Headline results | Citation |
|---|---|---|---|---|
| 2024-04-18 | Primary 6- and 12-month report · primary | — | Proportion with at least 50% fewer urgency-related incontinence episodes on a 7-day diary at 6 months after activation; intention-to-treat, imputed for 7 participants with missing 6-month data; performance goal 50%: 76.4%; P <0.0001 Met Same responder definition at 12 months after activation; intention-to-treat, imputed for 12 participants with missing 12-month data: 78.4%; P <0.0001 Responders among participants with a completed 12-month diary: 82% of 139; — Proportion with at least 10 points improvement in OAB-q health-related quality of life at 6 months; intention-to-treat; performance goal 50%: 83.6%; P <0.0001 Met Proportion with at least 50% fewer urgency-related incontinence episodes or at least 50% fewer large (severe) episodes at 12 months; intention-to-treat; performance goal 50%: 88.0%; P <0.0001 Met Among participants with at least 8 voids/day and at least 9 urgent episodes at baseline (n=113), proportion with at least 50% fewer PPIUS degree 3-4 urgent episodes or fewer than 8 voids/day at 6 months; intention-to-treat: 74.0%; P <0.0001 Met Mean urgency-related incontinence episodes per day at baseline, 6 months and 12 months, observed data: 4.8 at baseline; 1.4 at 6 months (n=144); 1.2 at 12 months (n=139); — Descriptive Participants with no leakage on at least 3 consecutive diary days at 12 months: 69/139 (50%); — Descriptive Symptoms better, much better or very much better at 12 months: 130/139 (93.5%); — Descriptive Responders in participants with and without prior percutaneous tibial nerve stimulation: prior PTNS 23/29 (79.3%); no prior PTNS 89/114 (78.1%); — | 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 DOI |
| 2024-11-25 | 24-month report · updated | — | Completers analysis: at least 50% fewer urgency-related incontinence episodes at 24 months on a 3-day diary: 77/97 (79%); — Completers analysis at 24 months: 54/97 (56%); — All implanted participants, last available visit carried forward; explanted participants counted as failures: 69.5%; — Participants with at least 50% fewer UUI episodes at one or more follow-up visits, among 149 with at least one post-activation visit: 136/149 (91%); — Descriptive Completers at 24 months: 27/97 (28%); — Descriptive Mean urgency-related leaks per day, baseline to 24 months: 4.5 to 1.3; — Descriptive At least 50% fewer moderate-to-severe urgency episodes (PPIUS degree 3-4) or normalized voids at 24 months: 61/97 (62.9%); — Descriptive Satisfied with therapy on the BSW questionnaire at 24 months: 88/91 (97%); — Descriptive | 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 DOI |
| 2026-02-23 | Quality-of-life analysis through 24 months · pro | — | Proportion with at least a 10-point improvement in total transformed HRQL score, completers, at 6, 12 and 24 months: 83.1% of 142 at 6 months; 85.4% of 137 at 12 months; 87.2% of 94 at 24 months; — BSW questionnaire at 24 months: benefit 96.8% (n=94); satisfaction 96.7% (n=91); willingness to continue 100% (n=94); — Descriptive Among 20 participants (20.6% of 97) with less than a 50% reduction in UUI episodes at 24 months; 18 completed the BSW: benefit 15/18 (83.3%); satisfied 12/18 (66.7%); willing to continue 18/18 (100%); — | 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;37(8):2451-2461. doi:10.1007/s00192-026-06538-2 DOI |
| 2026-04-13 | 36-month report · updated | — | Completers analysis: at least 50% fewer urgency-related incontinence episodes at 36 months on a 3-day diary: 71/90 (79%); — Completers analysis at 36 months: 57/90 (63%); — Completers on a 3-day diary at 36 months: 25/90 (28%); — Descriptive Mean urgency-related leaks per day, baseline to 36 months: 4.8 to 1.2; — Descriptive At least 50% fewer moderate-to-severe urgency episodes (PPIUS degree 3-4) or normalized voids at 36 months: 64/90 (71.1%); — Descriptive Satisfied with therapy on the BSW questionnaire at 36 months: 83/87 (95%); — Descriptive | 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;216(2):219-229. doi:10.1097/JU.0000000000005062 DOI |
References
1. 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
2. U.S. Food and Drug Administration. "De Novo Classification Request for Revi System." DEN220073. Decision date August 16, 2023. Decision summary; De Novo database entry
3. 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
4. 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;216(2):219-229. doi:10.1097/JU.0000000000005062
5. 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;37(8):2451-2461. doi:10.1007/s00192-026-06538-2