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Medtronic InterStim — Sacral Neuromodulation

InterStim is a family of sacral neuromodulation systems for bladder and bowel dysfunction. A lead near a sacral nerve connects to an implanted pulse generator; treatment modulates neural control rather than mechanically closing an outlet. This is the device hub. For assessment, test placement and operative technique, see Sacral Neuromodulation.[1]

Current Hardware and MRI Eligibility​

GeneratorPowerMRI-relevant lead combination
InterStim II — 3058Recharge-free978B1 SureScan can support conditional full-body 1.5 T/3 T scanning
InterStim X — 97800Recharge-free; extended battery generation978B1 SureScan
InterStim Micro — 97810Rechargeable978A1 SureScan

MRI eligibility depends on the complete system, not just the generator's name or whether its battery recharges. Older generators/leads and retained or damaged components require their own labeling review. It is incorrect to call every InterStim II head-only or to pair Micro's full-body eligibility with an older 3889 lead.[2]

Before scanning, verify model numbers, lead status, MRI mode and all scanner/coil/energy limits in the current instructions. A small observational series of off-label MRI does not override these requirements. External evaluation equipment is distinct from an eligible fully implanted system.[2]

InterStim X has a manufacturer-projected battery life exceeding a decade, potentially up to 15 years at low-energy settings. Micro requires periodic recharging; its advertised 20-minute weekly schedule and 15-year battery performance depend on specified settings and charger placement. These are product specifications, not promises of surgery-free treatment.[3]

Indications and Test Response​

Current US labeling covers urinary retention and OAB symptoms after conservative-treatment failure/intolerance, and chronic fecal incontinence after failure of or unsuitability for conservative treatment. Urinary mechanical obstruction must be excluded. The label contraindicates implantation without an appropriate response to test stimulation, inability to operate the system and diathermy.[4]

PNE and staged tined-lead evaluation are alternative ways to document response. Duration and programming depend on the clinical plan and system instructions. A favorable single-stage cost model or small case series does not establish that the test-response requirement can routinely be omitted. The initial test also does not guarantee long-term success.[5][6]

The 2024 AUA/SUFU OAB guideline supports shared decisions about minimally invasive treatment, including offering it without mandatory prior behavioral or drug trials. That treatment-sequencing recommendation is separate from the manufacturer's device eligibility and test-response requirements.[7]

High-Yield Clinical Evidence​

OAB and Non-Obstructive Retention​

InSite's prospective study tested 340 people and implanted 272. At five years, success was 67% in a modified-completers analysis versus 82% among completers. Those percentages use different assumptions about missing follow-up; neither is the success rate of all people initially considered for therapy.[8]

A separate older worldwide study implanted 152 patients after testing, including 31 with retention. At five years, reported success was 68% for urge incontinence, 56% for urgency-frequency and 71% for retention. In the retention cohort, catheterization frequency fell from 5.3 to 1.9/day on average. These selected-cohort results support benefit but do not prove retention is universally the best indication or predict catheter freedom for an individual.[9]

ROSETTA — SNM Versus Botulinum Toxin​

ROSETTA compared SNM with 200 U onabotulinumtoxinA in women with refractory UUI. At six months, toxin reduced daily UUI slightly more (3.9 versus 3.3 episodes; between-group difference 0.63), with more UTIs and temporary catheterization. The two-year extension evaluated clinical responders: data were available for 260/298, and mean UUI reduction did not differ significantly. Recurrent UTI was more frequent after toxin (24% versus 10%).[10][11]

The toxin dose was higher than the usual 100 U labeled idiopathic-OAB starting dose; see the botulinum toxin hub for indication-specific dosing. ROSETTA should not be presented as a direct comparison against every current100 U regimen or every newer SNM generator. Its economic study used 2018 US costs and modeled five-year outcomes, so it does not establish today's local lifetime cost ranking.[12]

Fecal Incontinence​

ASCRS 2023 considers SNM a first surgical option, with or without a sphincter defect—a conditional recommendation based on low-quality evidence. This does not mean every patient should proceed directly to surgery or that a structural defect is irrelevant to the broader evaluation.[13]

In a French cohort of 360 implanted patients, 162 (45%) had a favorable outcome at ten years, with 23% lost to follow-up; the Kaplan–Meier estimate was 64%. These are different estimands. A 2025 review of 36 long-term studies found benefits but judged all included studies at serious risk of bias and emphasized heterogeneous definitions.[14][15]

Neurological Disease and Other Off-Label Uses​

AUA/SUFU 2021 permits SNM in selected NLUTD patients with urgency, frequency and/or UUI (conditional, Grade C), and advises against offering it for NLUTD with spinal cord injury or spina bifida. This is not a recommendation for stress incontinence. Manufacturer safety/effectiveness remain unestablished for urinary dysfunction of neurological origin; selection requires explicit consideration of diagnosis, progression, MRI needs and alternative bladder management.[16][4]

High pooled success after permanent implantation can reflect selection of prior test responders. It should not be generalized to all neurological patients. IC/BPS, chronic pain, constipation and sexual symptoms have separate evidence and regulatory limitations; avoid using an observational pooled response as proof that SNM treats every pelvic-floor condition.[17][18]

Reintervention and Device Choice​

Pain, altered stimulation, infection, lead problems, loss of benefit and battery depletion may require reprogramming or surgery. In 32,454 older Medicare women, the estimated cumulative eight-year device-related reoperation incidence was 43%; this included generator replacement as well as revision/removal. It is not an eight-year revision rate for current Micro or X alone.[19]

A single-center retrospective study of 246 OAB patients found more revisions with rechargeable devices (34% of 150 versus 13.5% of 96); charging difficulty accounted for 35.3% of rechargeable revisions. This association does not establish a universal rechargeable “class effect,” nor does lack of a significant manufacturer difference prove devices equivalent. Current charging intervals, training, patient dexterity and ability to obtain support all matter.[20]

Accessory Safety Notice​

An April 2025 FDA recall concerned specified Enhanced Verify evaluation handsets, CFN HH90130FA, that could fail to communicate and interrupt evaluation therapy. Check the affected serial list and replacement instructions. This was an evaluation-handset action, not an instruction to explant functioning implanted InterStim systems.[21]

See also: Axonics, PTNS systems, Altaviva, Revi, eCoin.

References​

1. Noblett KL, Buono K. Sacral Nerve Stimulation as a Therapy for Patients With Refractory Voiding and Bowel Dysfunction. Obstetrics and Gynecology. 2018;132(6):1337-1345. doi:10.1097/AOG.0000000000002968

2. Medtronic. SureScan MRI Technology. US model/lead combinations and scanning precautions. MRI resource; complete current MRI manual library.

3. Medtronic. InterStim X and InterStim Micro systems. Current US product specifications. InterStim X; InterStim Micro.

4. Medtronic. InterStim Indications, Safety and Warnings. Current US manufacturer summary. Safety information.

5. Marcelissen T, Leong R, Serroyen J, van Kerrebroeck P, de Wachter S. Is the Screening Method of Sacral Neuromodulation a Prognostic Factor for Long-Term Success? The Journal of Urology. 2011;185(2):583-587. doi:10.1016/j.juro.2010.09.103

6. Lee W, Artenstein D, Tenggardjaja CF, et al. Single Institutional Experience With Single Stage Sacral Neuromodulation: Cost Savings and Outcomes. The Journal of Urology. 2020;203(3):604-610. doi:10.1097/JU.0000000000000576

7. AUA/SUFU. Idiopathic Overactive Bladder Guideline, 2024. Statements 23–25. Unabridged guideline.

8. Siegel S, Noblett K, Mangel J, et al. Five-Year Followup Results of a Prospective, Multicenter Study of Patients With Overactive Bladder Treated With Sacral Neuromodulation. The Journal of Urology. 2018;199(1):229-236. doi:10.1016/j.juro.2017.07.010

9. van Kerrebroeck PE, van Voskuilen AC, Heesakkers JP, et al. Results of Sacral Neuromodulation Therapy for Urinary Voiding Dysfunction: Outcomes of a Prospective, Worldwide Clinical Study. The Journal of Urology. 2007;178(5):2029-2034. doi:10.1016/j.juro.2007.07.032

10. Amundsen CL, Richter HE, Menefee SA, et al. OnabotulinumtoxinA vs Sacral Neuromodulation on Refractory Urgency Urinary Incontinence in Women: A Randomized Clinical Trial. JAMA. 2016;316(13):1366-1374. doi:10.1001/jama.2016.14617

11. Amundsen CL, Komesu YM, Chermansky C, et al. Two-Year Outcomes of Sacral Neuromodulation Versus OnabotulinumtoxinA for Refractory Urgency Urinary Incontinence: A Randomized Trial. European Urology. 2018;74(1):66-73. doi:10.1016/j.eururo.2018.02.011

12. Harvie HS, Amundsen CL, Neuwahl SJ, et al. Cost-Effectiveness of Sacral Neuromodulation Versus OnabotulinumtoxinA for Refractory Urgency Urinary Incontinence: Results of the ROSETTA Randomized Trial. The Journal of Urology. 2020;203(5):969-977. doi:10.1097/JU.0000000000000656

13. Bordeianou LG, Thorsen AJ, Keller DS, et al. ASCRS Clinical Practice Guidelines for the Management of Fecal Incontinence. Dis Colon Rectum. 2023;66:647–661. Official guideline.

14. Desprez C, Damon H, Meurette G, et al. Ten-Year Evaluation of a Large Retrospective Cohort Treated by Sacral Nerve Modulation for Fecal Incontinence: Results of a French Multicenter Study. Annals of Surgery. 2022;275(4):735-742. doi:10.1097/SLA.0000000000004251

15. Eggers E, Crouss T, Beausang J, et al. Long-Term Outcomes of Sacral Nerve Stimulation on the Treatment of Fecal Incontinence: A Systematic Review. Neuromodulation. 2025;28(5):715-726. doi:10.1016/j.neurom.2024.06.504

16. AUA/SUFU. Adult Neurogenic Lower Urinary Tract Dysfunction Guideline, 2021. Statements 49–50. Guideline.

17. van Ophoven A, Engelberg S, Lilley H, Sievert KD. Systematic Literature Review and Meta-Analysis of Sacral Neuromodulation in Neurogenic Lower Urinary Tract Dysfunction: Over 20 Years' Experience. Advances in Therapy. 2021;38(4):1987-2006. doi:10.1007/s12325-021-01650-9

18. Thaha MA, Abukar AA, Thin NN, Ramsanahie A, Knowles CH. Sacral Nerve Stimulation for Faecal Incontinence and Constipation in Adults. Cochrane Database of Systematic Reviews. 2015;(8):CD004464. doi:10.1002/14651858.CD004464.pub3

19. Bretschneider CE, Sheyn D, Lanki N, Volpe L, Gupta A. Device-Related Reoperations 8 Years Following Sacral Neuromodulation Implantation in Older Women. International Urogynecology Journal. 2024;35(12):2349-2355. doi:10.1007/s00192-024-05891-4

20. 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

21. FDA. Class 2 Device Recall: InterStim Enhanced Verify Evaluation Handset, CFN HH90130FA. Z-1704-2025, initiated April 3, 2025. Affected serials and corrective action.