Subcutaneous Nerve Stimulation for Failed Back Surgery Syndrome (FBSS) Patients

Study Overview
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Brief Summary
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The purpose of this study is to assess the safety and efficacy of Subcutaneous Nerve Stimulation (SQS) (also known as Peripheral Nerve Stimulation [PNS]) in the reduction of chronic, intractable post-surgical back pain in adults.

Detailed Description
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This study is a multi-center, prospective, randomized (1:1) parallel-group design.

Official Title
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SubQStim Pivotal Study: A Prospective, Randomized, Controlled Study to Evaluate the Safety and Efficacy of Subcutaneous Nerve Stimulation. Protocol 1666

Conditions
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Failed Back Surgery Syndrome, Post-laminectomy Syndrome

Intervention / Treatment
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* Device: PrimeAdvanced® neurostimulator system


Participation Criteria
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Eligibility Criteria
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Key Inclusion Criteria: Have persistent back pain for at least 6 months Had back surgery at least 6 months ago Have tried pain medications and physical therapy Read and understand written English or Spanish Male or non-pregnant female. If female of child-bearing potential, and if sexually active, must be using a medically-acceptable method of birth control during study participation Willing and able to undergo surgical implant procedure, attend visits as scheduled, and comply with the study requirements Have an expected lifespan greater than 12 months Key Exclusion Criteria: Have leg pain in addition to back pain. Currently enrolled in or plan to enroll in another drug and/or device study Have peripheral vascular disease, peripheral neuropathy, small-fiber neuropathy, or fibromyalgia Have an active systemic infection or are immunocompromised Will be exposed to diathermy or anticipate needing a full-body MRI scan Currently have an implantable cardiac pacemaker, defibrillator, or neurostimulator Treated with spinal cord stimulation, peripheral nerve stimulation, an intrathecal drug delivery system or requires additional back surgery

Ages Eligible for Study
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Minimum Age: 22 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Treatment<br>Treatment settings of Medtronic PrimeAdvanced® neurostimulator system implant | Device: PrimeAdvanced® neurostimulator system<br>* Neurostimulator and associated components<br>|
| Other: Control<br>Control settings of Medtronic PrimeAdvanced® neurostimulator system implant | Device: PrimeAdvanced® neurostimulator system<br>* Neurostimulator and associated components<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Back Pain Responders (Subjects Who Achieve at Least a 50% Reduction in Average Back Pain With no Increase in Prescription Pain Medications) From Baseline to Month 3 Post-device Activation. | Number of responders in Treatment and Control groups. Subjects reported typical back pain (0=no pain, 10=worst pain) during the Baseline (BL) and Blinded Phase (M3) periods. Percentage reduction in average back pain was calculated as (BL-M3)/BL. Subjects with at least a 50% reduction in average back pain between Baseline and Month 3, with no increase in prescribed pain medications, were considered responders. | Baseline to 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Functional Disability | Compare the difference in average improvement in disability (as measured by Oswestry Disability Index (ODI)) from Baseline to Month 3 between the Treatment and Control groups. ODI ranges from 0% (no disability) -100% (greatest disability). Change is calculated as Baseline - Month 3 with a positive change indicating improvement in disability. Subjects with missing Baseline and/or Month 3 ODI assessments were counted as no change (Baseline - Month 3 = 0). | Baseline to 3 months | 
| Subject Satisfaction | Compare difference in number of subjects satisfied with therapy between the Treatment and Control groups at Month 3. Subjects who reported they were very or somewhat satisfied with the therapy were counted as satisfied. Subjects with no satisfaction response were excluded from the analysis. | 3 months | 
| Quality of Life: Physical | Compare the average change in quality of life (as measured by Short Form Health Survey (SF36 v2): Physical component score (PCS)) from Baseline to Month 3 between subjects in the Treatment and Control groups. The PCS ranges from 0 (worst possible physicial quality of life) to 100 (best possible physical quality of life). Change was calculated as Month 3 - Baseline, with a positive difference indicating improvement in physical quality of life. Subjects with missing Baseline and/or Month 3 SF-36: PCS assessments were counted as no change (Month 3 - Baseline = 0). | Baseline to 3 months | 
| Quality of Life: Mental | Compare the average change in quality of life (as measured by Short Form Health Survey (SF36 v2): Mental component score (MCS)) from Baseline to Month 3 between subjects in the Treatment and Control groups. The MCS ranges from 0 (worst possible mental quality of life) to 100 (best possible mental quality of life). Change was calculated as Month 3 - Baseline, with a positive difference indicating improvement in mental quality of life. Subjects with missing Baseline and/or Month 3 SF-36: MCS assessments were counted as no change (Month 3 - Baseline = 0). | Baseline to 3 months | 
| Worst Back Pain | Compare the average improvement in worst back pain from Baseline to Month 3 between the Treatment and Control groups. Subjects reported worst back pain (0 (no pain) - 10 (worst pain)) during the Baseline and Blinded Phase (Month 3) periods. Change was calculated as Baseline - Month 3, with a positive change indicating improvement in worst back pain. | Baseline to 3 months |