Sacroiliac (SI) Joint Transfixing and Fusion: Meaningful Long Term Outcomes With Nevro1 (SIMON1)

A Post-market, Multicenter, Prospective, Clinical Study to Evaluate the Nevro1 Sacroiliac (SI) Transfixing and Fusion System for the Treatment of Sacroiliac Joint Dysfunction

The goal of this observational study is to learn if Nevro1 Sacroiliac Transfixing and Fusion System can treat sacroiliac joint dysfunction in males or females over 21. The main questions it aims to answer is what percentage of patients have clinically important pain relief with no adverse events, and what proportion of patients have fusion of the sacroiliac joint at 1 year and 2 years.

Study Overview

• Status: Completed
• Conditions: Sacroiliac Joint Dysfunction
• Intervention / Treatment: Device: Sacroiliac Joint transfixing and fusion system (Nevro1)

• Study Type: Observational
• Enrollment (Actual): 180

Contacts and Locations

Study Locations

• United States
  • California
    • Lodi, California, United States, 95240
      • AIRS Clinic
  • Michigan
    • Southfield, Michigan, United States, 48033
      • Michigan Orthopaedic Surgeons
  • North Carolina
    • Winston-Salem, North Carolina, United States, 27103
      • Carolinas Pain Institute
  • Texas
    • Spring, Texas, United States, 77380
      • Advanced Spine and Pain Specialists
    • The Woodlands, Texas, United States, 77384
      • Procura Pain and Spine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Cohort will be selected from participating clinics

Description

Inclusion Criteria:

1. Has medical insurance that covers this standard of care procedure and all other anticipated and unanticipated procedure-related care, and all coverage criteria required by insurer are met, which may include but are not limited to:

   • Has had low back and/or buttock pain for at least 6 months that is inadequately responsive to non-surgical care
   • Has a positive Fortin's test
   • Has a diagnosis of SIJ dysfunction (degenerative sacroiliitis or SI disruption) with pain elicited on at least 3 of 5 provocative tests (FABER, Gaenslen, Distraction, Thigh Thrust, Compression).
   • At least 75% reduction in pain for the expected duration of two anesthetics (on separate visits each with a different duration of action), and the ability to perform previously painful maneuvers, following an image-guided, contrast-enhanced intra-articular (diagnostic) SIJ injection
   • A trial of at least one therapeutic intra-articular SIJ injection (i.e. corticosteroid injection)
2. Has an ODI score ≥30% at enrollment
3. Has a SI joint pain score of at least 5 out of 10 on numerical rating scale at enrollment.
4. Be at least 21 years of age at enrollment
5. The patient's physician has decided that the best treatment for the patient's SIJ dysfunction is the Nevro1 SI Fixation System, and the patient has agreed to the treatment
6. Be willing and capable of giving written informed consent
7. Be mentally and physically able to comply with study-related requirements and procedures and attend all scheduled visits

Exclusion Criteria:

1. Has current severe back pain due to other causes, such as lumbar disc degeneration, lumbar disc herniation, lumbar spondylolisthesis, lumbar spinal stenosis, lumbar facet degeneration, lumbar radicular pain, and lumbar vertebral body fracture
2. Has SIJ pain secondary to inflammatory conditions or other known sacroiliac pathology such as: Sacral dysplasia, inflammatory sacroiliitis (e.g., ankylosing spondylitis or other HLA-associated spondylo-arthropathy), tumor, infection, acute fracture, and crystal arthropathy
3. Has had a previous SIJ implant placement, including an allograft
4. Has had an injection with corticosteroid into the index SIJ within the last 30 days
5. Has had a sacral radiofrequency ablation within the last 6 months
6. Has a history of recent (<1 year) major trauma to pelvis
7. Has previously diagnosed or suspected severe osteoporosis (defined as prior T-score < -2.5 or history of osteoporotic fracture)
8. Has a chronic rheumatologic condition (e.g., rheumatoid arthritis)
9. Has a known allergy to titanium or titanium alloys
10. Has a current local or systemic infection that raises the risk of surgery
11. Is currently receiving or seeking short- or long-term worker's compensation related to the SI joint or low back pain, is currently receiving disability remuneration related to SI joint or low back pain, and/or is currently involved in injury litigation related to the SI joint or low back pain
12. Is participating in an investigational study or has been involved in an investigational study within 3 months prior to enrollment
13. Has any condition or anatomy that makes treatment with the Nevro1 SI Fixation System infeasible
14. Is taking a medication known to have detrimental effects on bone quality and soft tissue healing
15. Has a prominent neurologic condition that would interfere with physical therapy
16. Be pregnant or plan on becoming pregnant in the next two years.
17. Has a medical condition or pain in other area(s), not intended to be treated in this study, that could interfere with study procedures, accurate pain reporting, and/or confound evaluation of study endpoints, as determined by the Investigator

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Treated Group; Treated with Nevro1 transfixing and fusion system	Device: Sacroiliac Joint transfixing and fusion system (Nevro1); The Nevro1 is a titanium cage the is implanted in the sacroiliac join from a posterior direction, and then anchors are deployed that stabilize the joint. It has multiple openings to allow surgeons to fill them with autogenous bone graft to encourage bone bridging through the implant for SIJ fusion.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Composite Pain Relief and Safety Responder	The proportion of patient meeting the following criteria: NRS score for SIJ pain reduced by at least 2 points from baseline.; Absence of implant-related serious adverse events (SAEs).; Absence of neurologic worsening related to the lumbosacral nerve roots.; Absence of reoperation (removal, revision reoperation or supplemental fixation) for SIJ pain.	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Timed "Up and Go" Performance test (TUG)	Absolute change from baseline in time to perform the TUG.	6 months
Change in Disability	Absolute change from baseline in Oswestry Disability Index (ODI) score. The total score ranges from 0 (minimal disability) to 100 (severe disability, e.g., bedridden).	6 months
Patient Global Impression of Change (PGIC)	Proportion of patients reporting "Better" or "A great deal better" on the PGIC. The PGIC is a 7-point scale with responses ranging from "no change (or condition has gotten worse)" to "a great deal better".	6 months
Physical and Mental Health Summary (PROMIS-29)	Absolute change from baseline in PROMIS-29 score. Higher scores represent greater impact of pain on a patients life in the domains of physical function, fatigue, pain interference, depressive symptoms, anxiety, ability to participate in social roles and activities, and sleep disturbance.	6 months
Change in Quality of Life	Absolute change from baseline in the index score of EuroQol 5-dimension 5 level (EQ-5D-5L) a standardized measure of health status. The index score ranges from zero to one, with one representing the highest possible health state.	6 months
Change in Sleep Disturbance Due to Pain	Absolute change from baseline in Pain and Sleep Questionnaire Three-Item Index (PSQ-3) score. The scale ranges from 0 (pain does not affect sleep) to 30 (pain has maximum effect on sleep).	6 months

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Presence of bone apposition on implant surface	Grading of the presence of bone apposition on the device adjacent to the sacrum and ilium.	12 and 24 months
Presence of bony fusion across the sacroiliac joint	Grading of the presence of bony fusion across the sacroiliac joint.	12 and 24 months
Presence of radiolucency at the implant surface	Grading of the presence of radiolucency at the device surface adjacent to the sacrum and ilium.	12 and 24 months
Proportion of patients with different levels of treatment response	Evaluating different pain relief response rates, defining responder as a participant who experiences ≥30%, ≥50% and ≥80% pain relief vs. Baseline as measured by NRS.	3, 6, 12, and 24 months
Sub-analysis comparing outcomes between age groups	All outcomes will be compared between the two age groups: 21 to 70 years, and 71 years and above.	3, 6, 12, and 24 months.
Rate of adverse events	Proportion of patients who experience and adverse event related to the procedure or device including infection, device breakage, migration, neurological worsening, and procedural blood loss.	Implant, 1, 3, 6, 12, and 24 months.

Collaborators and Investigators

• Sponsor: Nevro Corp
• Investigators: Study Director: Rose P Azalde, MS, Nevro Corp

Study record dates

Study Major Dates

• Study Start (Actual): April 3, 2025
• Primary Completion (Actual): May 21, 2025
• Study Completion (Actual): May 21, 2025

Study Registration Dates

• First Submitted: March 27, 2025
• First Submitted That Met QC Criteria: March 27, 2025
• First Posted (Actual): April 3, 2025

Study Record Updates

• Last Update Posted (Actual): June 25, 2026
• Last Update Submitted That Met QC Criteria: June 23, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: sacroiliac joint pain; Sacroiliac transfixing; sacroiliac fusion
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Joint Diseases
• Other Study ID Numbers: CA2024-02 US SIJ-PM

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Study data will be reported with descriptive statistics describing group level outcomes, not individual outcomes.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No