Patient Observational Pain and Activity Survey (POPAS) Study Using RS-4i Sequential Stimulator With Intersperse Technology in Axial Spine and Peripheral Joint Pain

Spine pain and joint pain are among the most common worldwide ailments and directly contributes to disability as well as increased duration of care. Spine and joint pain affect work sick leave, production and increased financial costs to healthcare. Non-invasive treatments for spine and joint pain can vary widely from lifestyle changes, physical therapy, oral medication, and select medical devices, that can improve pain level and help improve the quality of life of individuals. Thus, the general population suffers from an ailment that has multiple conservative treatment options with variable outcomes.

Transcutaneous Electrical Neuromuscular Stimulation (TENS) has been show to decrease pain and restore function. Interferential therapy (INF) is a specific signal type that is effective for reducing musculoskeletal pain. Neuromuscular Electrical Stimulation (NMES) uses a specific signal type to cause muscles to contract and therefore provide functional improvement. The RS-4i Plus is an FDA-regulated prescription TENS medical device that outputs an INF signal and a NMES signal, and a unique Intersperse signal, which combines NMES and INF into a single treatment. Therefore, the goal of this study is to determine if use of the prescribed RS-4i Plus in patients presenting with pain, axial or peripheral joint, can be efficacious in decreasing the patient's pain and improving their activity measured at one month, three months, and six months of use.

Study Overview

• Status: Completed
• Conditions: Osteoarthritis
• Intervention / Treatment: Device: RS-4i Plus

• Study Type: Observational
• Enrollment (Actual): 69

Contacts and Locations

Study Locations

• United States
  • California
    • Orange, California, United States, 92868
      • University of California at Irvine Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 89 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Subjects will be current adult patients of the UCI PM&R or Orthopedic Department

Description

Inclusion Criteria:

1. chronic and persistent MSK lumbar back pain for greater than 12 weeks as documented in patient records
2. Age 18 to 89
3. Willingness to comply with study protocol
4. Signed Patient Consent on file
5. Verified patient usage collected from RS-4i Plus via patient data adapter

Exclusion Criteria:

1. Pregnancy
2. Any contraindications, as indicated in the RS-4i Plus prescribing information
3. Substantial allergy to adhesives
4. Skin infection or irritation of skin where electrodes are to be placed
5. Pacemaker/ICD
6. Abnormal skin sensation
7. Serious psychological disorder
8. End-stage cardiac, peripheral arterial or pulmonary disease
9. h/o recent vertebral fracture
10. Severe degenerative or traumatic neuromuscular disease
11. Non-English speaking
12. Uncontrolled diabetes meelitus (Hb A1c> 8.5%)
13. ESRD or ESHD
14. Active cancer

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

Number of groups / cohorts

6

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Axial Spine only, Age 65+	Device: RS-4i Plus; RS-4i Plus in an FDA-regulated prescription TENS medical device that outputs and INF signal and a NMES signal and Intersperse signal, which combines INF and NMES into a single treatment.
Axial Spine only, Age 18-64	Device: RS-4i Plus; RS-4i Plus in an FDA-regulated prescription TENS medical device that outputs and INF signal and a NMES signal and Intersperse signal, which combines INF and NMES into a single treatment.
Peripheral Joint only, Age 65+	Device: RS-4i Plus; RS-4i Plus in an FDA-regulated prescription TENS medical device that outputs and INF signal and a NMES signal and Intersperse signal, which combines INF and NMES into a single treatment.
Peripheral Joint only, Age 18-64	Device: RS-4i Plus; RS-4i Plus in an FDA-regulated prescription TENS medical device that outputs and INF signal and a NMES signal and Intersperse signal, which combines INF and NMES into a single treatment.
Axial + Peripheral Joint, Age 65+	Device: RS-4i Plus; RS-4i Plus in an FDA-regulated prescription TENS medical device that outputs and INF signal and a NMES signal and Intersperse signal, which combines INF and NMES into a single treatment.
Axial + Peripheral Joint, Age 18-64	Device: RS-4i Plus; RS-4i Plus in an FDA-regulated prescription TENS medical device that outputs and INF signal and a NMES signal and Intersperse signal, which combines INF and NMES into a single treatment.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Level of Pain / Function using NRS	Outcome with be rated on a scale of 0-10, in which 10 is the most severe pain / worst function and 0 is the least pain / best function. The time frame will include assessment at 1 month interval to determine if the intervention is showing a change / long term improvement in the pain / function	1 month
Level of Pain / Function using NRS	Outcome with be rated on a scale of 0-10, in which 10 is the most severe pain / worst function and 0 is the least pain / best function. The time frame will include assessment at 3 month interval to determine if the intervention is showing a change / long term improvement in the pain / function	3 month
Level of Pain / Function using NRS	Outcome with be rated on a scale of 0-10, in which 10 is the most severe pain / worst function and 0 is the least pain / best function. The time frame will include assessment at 6 month interval to determine if the intervention is showing a change or long term improvement in the pain / function	6 months

Collaborators and Investigators

• Sponsor: University of California, Irvine

Study record dates

Study Major Dates

• Study Start (Actual): January 9, 2023
• Primary Completion (Actual): June 30, 2024
• Study Completion (Actual): June 30, 2024

Study Registration Dates

• First Submitted: July 25, 2022
• First Submitted That Met QC Criteria: July 27, 2022
• First Posted (Actual): July 28, 2022

Study Record Updates

• Last Update Posted (Actual): June 8, 2025
• Last Update Submitted That Met QC Criteria: June 6, 2025
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Musculoskeletal Diseases; Joint Diseases; Arthralgia
• Other Study ID Numbers: 20216774

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes