Failed Back Surgery Syndrome, Post-laminectomy Syndrome
Conditions
Brief summary
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
This study is a multi-center, prospective, randomized (1:1) parallel-group design.
Interventions
DEVICEPrimeAdvanced® neurostimulator system
Neurostimulator and associated components
Sponsors
MedtronicNeuro
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Caregiver, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
22 Years to No maximum
Healthy volunteers
No
Inclusion criteria
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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. | Baseline to 3 months | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Functional Disability | Baseline to 3 months | 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). |
| Subject Satisfaction | 3 months | 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. |
| Quality of Life: Physical | Baseline to 3 months | 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). |
| Quality of Life: Mental | Baseline to 3 months | 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). |
| Worst Back Pain | Baseline to 3 months | 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. |
Countries
United States
Participant flow
Recruitment details
This study enrolled adult patients with chronic, intractable post-surgical back pain. First enrollment was in April 2013. Enrollment was suspended in September 2014 due to slow enrollment. The last subject visit was in March 2016. The planned enrollment was 323 subjects, with 218 randomized. Actual enrollment was 137 subjects with 62 randomized.
Pre-assignment details
Of the 137 enrolled subjects, 62 were implanted and randomized. Of the 75 subjects who discontinued from the study prior to randomization, 54 did not meet inclusion/exclusion criteria, 12 withdrew consent or declined device implant, 3 discontinued due to study suspension, and 6 discontinued for other reasons.
Participants by arm
| Arm | Count |
|---|---|
| Treatment Treatment settings of Medtronic PrimeAdvanced® neurostimulator system implant
PrimeAdvanced® neurostimulator system: Neurostimulator and associated components | 32 |
| Control Control settings of Medtronic PrimeAdvanced® neurostimulator system implant
PrimeAdvanced® neurostimulator system: Neurostimulator and associated components | 30 |
| Total | 62 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Blinded Phase (Randomization - 3 Months) | Adverse Event | 0 | 1 |
| Open Label Phase (3-12 Months) | Early study closure | 17 | 10 |
| Open Label Phase (3-12 Months) | Physician Decision | 1 | 0 |
Baseline characteristics
| Characteristic | Treatment | Control | Total |
|---|---|---|---|
| Age, Continuous | 60.6 years STANDARD_DEVIATION 13.1 | 59.8 years STANDARD_DEVIATION 13.7 | 60.2 years STANDARD_DEVIATION 13.3 |
| Back pain | 6.77 units on a scale STANDARD_DEVIATION 1.25 | 6.66 units on a scale STANDARD_DEVIATION 0.88 | 6.71 units on a scale STANDARD_DEVIATION 1.08 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 0 Participants | 1 Participants | 1 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 32 Participants | 29 Participants | 61 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Black or African American | 2 Participants | 0 Participants | 2 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 2 Participants | 2 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 30 Participants | 28 Participants | 58 Participants |
| Region of Enrollment United States | 32 participants | 30 participants | 62 participants |
| Sex: Female, Male Female | 18 Participants | 16 Participants | 34 Participants |
| Sex: Female, Male Male | 14 Participants | 14 Participants | 28 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 32 | 0 / 30 |
| other Total, other adverse events | 11 / 32 | 8 / 30 |
| serious Total, serious adverse events | 2 / 32 | 0 / 30 |
Outcome results
Primary
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.
Time frame: Baseline to 3 months
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| Treatment | 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. | 9 Participants |
| Control | 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. | 5 Participants |
Comparison: The original sample size estimate for the primary objective was based on the following assumptions: 109 subjects in each arm with a responder rate of 22% in the Control group and 40% in the Treatment group, and a one-sided α= 0.05 using a Z test with unpooled variance, would result in 90% power. Because the study terminated early, the actual sample size (32 in Treatment, 30 in Control) resulted in 47% power under the same assumptions.p-value: 0.14Z-test
Secondary
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).
Time frame: Baseline to 3 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Treatment | Functional Disability | 9.8 units on a scale | Standard Deviation 14.3 |
| Control | Functional Disability | 10.0 units on a scale | Standard Deviation 12.1 |
Secondary
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).
Time frame: Baseline to 3 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Treatment | Quality of Life: Mental | 1.9 units on a scale | Standard Deviation 10 |
| Control | Quality of Life: Mental | 1.4 units on a scale | Standard Deviation 9.6 |
Secondary
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).
Time frame: Baseline to 3 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Treatment | Quality of Life: Physical | 3.6 units on a scale | Standard Deviation 8.6 |
| Control | Quality of Life: Physical | 3.1 units on a scale | Standard Deviation 7.1 |
Secondary
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.
Time frame: 3 months
Population: The analysis population includes all randomized subjects, with the exception of one subject in the Control group who did not have a satisfaction value. This subject was excluded from the analysis.
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| Treatment | Subject Satisfaction | 25 Participants |
| Control | Subject Satisfaction | 22 Participants |
Secondary
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.
Time frame: Baseline to 3 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Treatment | Worst Back Pain | 2.7 units on a scale | Standard Deviation 2.6 |
| Control | Worst Back Pain | 1.6 units on a scale | Standard Deviation 1.9 |