Post-Approval Clinical Trial Comparing the Long Term Safety and Effectiveness Coflex vs. Fusion to Treat Lumbar Spinal Stenosis

• ClinicalTrials.gov Identifier: NCT00534235
• Recruitment Status: Completed
• First Posted: September 24, 2007
• Results First Posted: February 27, 2019
• Last Update Posted: February 6, 2020
• Sponsor: Paradigm Spine
• Collaborator: MCRA
• Information provided by (Responsible Party): Paradigm Spine

Study Description

Brief Summary:

Post-Approval Clinical Study Comparing the Long Term Safety and Effectiveness of coflex vs. Fusion to Treat Lumbar Spinal Stenosis

Condition or disease	Intervention/treatment	Phase
Spinal Stenosis	Procedure: Decompression; Device: Posterolateral Fusion and Implantation of Pedicle Screws; Device: Implantation of coflex Interlaminar Technology	Not Applicable

Detailed Description:

The primary objective of this post-approval study is to examine the long-term survivorship of the coflex®. The coflex® Interlaminar Technology is an interlaminar stabilization device indicated for use in one or two level lumbar stenosis from L1-L5 in skeletally mature patients with at least moderate impairment in function, who experience relief in flexion from their symptoms of leg/buttocks/groin pain, with or without back pain, and who have undergone at least 6 months of non-operative treatment. The coflex® is intended to be implanted midline between adjacent lamina of 1 or 2 contiguous lumbar motion segments. Interlaminar stabilization is performed after decompression of stenosis at the affected level(s).

Study Design

• Study Type: Interventional (Clinical Trial)
• Actual Enrollment: 322 participants
• Allocation: Randomized
• Intervention Model: Parallel Assignment
• Masking: Single (Participant)
• Primary Purpose: Treatment
• Official Title: Post-Approval Study to Investigate The Long Term (5-Year) Survivorship of Coflex Compared to Control Fusion Study Patients
• Study Start Date: October 2012
• Actual Primary Completion Date: December 2015
• Actual Study Completion Date: December 2015

Arms and Interventions

Arm	Intervention/treatment
Active Comparator: Posterolateral Fusion w/Pedicle Screws; Control: Posterolateral fusion and implantation of pedicle screws after decompression	Procedure: Decompression; Either microsurgical decompression or laminotomy to remove bone impinging on nerves causes the patient pain; Device: Posterolateral Fusion and Implantation of Pedicle Screws
Active Comparator: coflex Interlaminar Technolgy; Investigative: Implantation of coflex Interlaminar Technology after decompression	Procedure: Decompression; Either microsurgical decompression or laminotomy to remove bone impinging on nerves causes the patient pain; Device: Implantation of coflex Interlaminar Technology

Outcome Measures

Primary Outcome Measures :

1. Number of Subjects With Improvement of at Least 15 Points in ODI [ Time Frame: 5 years ]
   The primary variable of performance is the assessment of Oswestry Low Back Pain Disability Index (ODI) in both treatment groups at 5 years. It will be assessed if the improvement in ODI since the pre surgery status in the coflex™ group is better than the improvement in the control group (scale 0-100 with a higher score representing increased disability).
2. Number of Subjects With no Reoperations, Revisions, Removals, or Supplemental Fixation [ Time Frame: 5 years ]
   Assessment of secondary surgical interventions, i.e., reoperations, revisions, removals, or supplemental fixation associated with either coflex or control group. Refer to FDA guidance for complete definitions (https://www.fda.gov/RegulatoryInformation/Guidances/ucm072263.htm).
3. Number of Subjects With no Major Device Related Complications [ Time Frame: 5 years ]
   Assessment of major device-related complications at 5 years
4. Number of Subjects With no Epidural Injection(s) [ Time Frame: 5 years ]
   Assessment of lumbar epidural injections
5. Number of Subjects With no Persistent New or Increasing Sensory or Motor Deficit [ Time Frame: 5 years ]
   No persistent new or increasing sensory or motor deficit
6. Number of Subjects With no Persistent New or Increasing Sensory Deficit [ Time Frame: 5 years ]
   No persistent new or increasing sensory deficit
7. Number of Subjects With no Persistent New or Increasing Motor Deficit [ Time Frame: 5 years ]
   No persistent new or increasing motor deficit
8. Number of Subjects With no Reoperations or Epidural (Up to Day 1825) [ Time Frame: 5 years ]
   No reoperations, revisions, removals or supplemental fixation and no epidural injection at any lumbar level up to and including the Month 60 visit.

Secondary Outcome Measures :

1. Number of Subjects With a Decrease in Zurich Claudication Questionnaire (ZCQ) Symptom Severity of at Least 0.5 Points [ Time Frame: 5 years ]
   ZCQ is a scale that measures physical function, symptom severity, and patient satisfaction for patients with spinal stenosis. Scores range from 1-5 with a higher score indicating worsening disability.
2. Number of Subjects With Decrease in Zurich Claudication Questionnaire (ZCQ) Physical Function of at Least 0.5 Points [ Time Frame: 5 years ]
   ZCQ is a scale that measures physical function, symptom severity, and patient satisfaction for patients with spinal stenosis.
3. Number of Subjects With Maintenance or Improvement in SF-12 Physical Function Component [ Time Frame: 5 years ]
   Assessment of the patient's Quality of Life as measured by SF-12. Scores range from 0 to 100, where a zero score indicates the lowest level of health. Success was defined as subjects who maintained or improved from their SF-12 score at baseline.
4. Number of Subjects With Maintenance or Improvement in SF-12 Mental Health Component [ Time Frame: 5 years ]
   Assessment of the patient's Quality of Life as measured by SF-12. Scores range from 0 to 100, where a zero score indicates the lowest level of health. Success was defined as subjects who maintained or improved from their SF-12 score at baseline.
5. Number of Subjects With a Decrease in VAS Back Pain of at Least 20mm [ Time Frame: 5 years ]
   Improvement of the Visual Analog Scale (VAS) for low back pain (on the 100 mm scale) compared to control group. On a scale of 0 to 100, 0 indicates no pain and 100 indicates worst pain imaginable.
6. Number of Subjects With Decrease VAS Worse Leg Pain of at Least 20mm [ Time Frame: 5 years ]
   Improvement of the Visual Analog Scale (VAS) for leg pain (on the 100 mm scale) compared to control group. On a scale of 0 to 100, 0 indicates no pain and 100 indicates worst pain imaginable.
7. Mean Oswestry Disability Index (ODI) Score [ Time Frame: 5 years ]
   Assessment of disability from low back pain as measured by ODI (Oswestry Disability Index) mean score in each treatment group at 5 years. On a scale of 0-100, a higher score represents increased disability.
8. Mean Visual Analog Scale Back Pain Score [ Time Frame: 5 years ]
   Assessment of Back Pain as measured by VAS mean score in each treatment group at 5 years. On a scale of 0-100mm, a higher score represents worse pain.
9. Mean Visual Analog Scale Leg (Worse) Pain Score [ Time Frame: 5 years ]
   Assessment of Worse Leg Pain by VAS mean score in each treatment group at 5 years. On a scale of 0-100mm, a higher score represents worse pain.
10. Mean Visual Analog Scale (VAS) Leg (Right) Pain Score [ Time Frame: 5 years ]
    Assessment of Right Leg Pain by VAS mean score in each treatment group at 5 years. On a scale of 0-100mm, a higher score represents worse pain.
11. Mean Visual Analog Scale (VAS) Leg (Left) Pain Score [ Time Frame: 5 years ]
    Assessment of Left Leg Pain by VAS mean score in both treatment groups at 5 years. On a scale of 0-100mm, a higher score represents worse pain.
12. Number of Subjects With a Decrease in VAS Right Leg Pain of at Least 20mm [ Time Frame: 5 years ]
    Improvement of the Visual Analog Scale (VAS) for low back pain (on the 100 mm scale) compared to control group. On a scale of 0 to 100, 0 indicates no pain and 100 indicates worst pain imaginable.
13. Number of Subjects With a Decrease in VAS Left Leg Pain of at Least 20mm [ Time Frame: 5 years ]
    Improvement of the Visual Analog Scale (VAS) for low back pain (on the 100 mm scale) compared to control group. On a scale of 0 to 100, 0 indicates no pain and 100 indicates worst pain imaginable.
14. Mean Zurich Claudication Questionnaire (ZCQ) Symptom Severity Score [ Time Frame: 5 years ]
    Assessment of symptom severity by ZCQ mean score in both treatment groups at 5 years. ZCQ is a scale that measures physical function, symptom severity, and patient satisfaction for patients with spinal stenosis. Scores range from 1-5 with a higher score indicating worsening disability.
15. Mean Zurich Claudication Questionnaire (ZCQ) Physical Function Score [ Time Frame: 5 years ]
    Assessment of physical function by ZCQ mean score in both groups at 5 years. ZCQ is a scale that measures physical function, symptom severity, and patient satisfaction for patients with spinal stenosis. Scores range from 1-5 with a higher score indicating worsening disability.
16. Mean Short Form-12 Physical Component Score [ Time Frame: 5 years ]
    Assessment of the patient's Quality of Life as measured by SF-12 mean score in both treatment groups at 5 years. Scores range from 0 to 100, where a zero score indicates the lowest level of health.
17. Mean Short Form-12 Mental Component Score [ Time Frame: 5 years ]
    Assessment of the patient's Quality of Life as measured by SF-12 mean score in both treatment groups at 5 years. Scores range from 0 to 100, where a zero score indicates the lowest level of health.
18. Patient Survey: Satisfaction [ Time Frame: 5 years ]
    Subjects who responded "Very Satisfied" or "Somewhat Satisfied".
19. Patient Survey: Recommendation of Treatment [ Time Frame: 5 years ]
    Subjects who responded "Definitely Yes" or "Probably Yes"
20. Pain Management: Class II Narcotics Usage by Device Group [ Time Frame: 5 years ]
    Number of subjects using Class II narcotics
21. Pain Management: NSAIDs/ASA/Acetaminophen Usage by Device Group [ Time Frame: 5 years ]
    Number of subjects using NSAIDs/ASA/Acetaminophen

Other Outcome Measures:

1. Mean Rotation (F to E) in Degrees - At Level(s) of Implant [ Time Frame: 5 years ]
   As determined by independent radiographic lab, this is the average measure of rotation (flexion to extension) at the index level(s) in both treatment groups at 5 years.
2. Rotation (F to E) in Degrees - Below Level of Implant [ Time Frame: 5 years ]
   As determined by independent radiographic lab, this is the average measure of rotation (flexion to extension) at the level below the implant in both treatment groups at 5 years.
3. Rotation (F to E) in Degrees - Above Level of Implant [ Time Frame: 5 years ]
   As determined by independent radiographic lab, this is the average measure of rotation (flexion to extension) at the level above the implant in both treatment groups at 5 years.
4. Translation (mm) - At Level(s) of Implant [ Time Frame: 5 years ]
   As determined by independent radiographic lab, this is the average measure of translation at the index level(s) in both treatment groups at 5 years.
5. Translation (mm) - Below Level of Implant [ Time Frame: 5 years ]
   As determined by independent radiographic lab, this is the average measure of translation at the level below the implant in both treatment groups at 5 years.
6. Translation (mm) - Above Level of Implant [ Time Frame: 5 years ]
   As determined by independent radiographic lab, this is the average measure of translation at the level above the implant in both treatment groups at 5 years.
7. Anterior Disc Height (mm) - At Level(s) of Implant [ Time Frame: 5 years ]
   As determined by independent radiographic lab, this is the average measure of anterior disc height at the index level(s) in both treatment groups at 5 years.
8. Posterior Disc Height (mm) - At Level(s) of Implant [ Time Frame: 5 years ]
   As determined by independent radiographic lab, this is the average measure of posterior disc height at the index level(s) in both treatment groups at 5 years.
9. Translation (F to E) in Percent (%) - At Level(s) of Implant [ Time Frame: 5 years ]
   As determined by independent radiographic lab, this is the percentage of translation at the index level(s) in both treatment groups at 5 years.
10. Translation (F to E) in Percent (%) - Below Level of Implant [ Time Frame: 5 years ]
    As determined by independent radiographic lab, this is the percentage of translation at the level below the implant in both treatment groups at 5 years.
11. Translation (F to E) in Percent (%) - Above Level of Implant [ Time Frame: 5 years ]
    As determined by independent radiographic lab, this is the percentage of translation at the level above the implant in both treatment groups at 5 years.
12. Average Disc Height (mm) - At Level(s) of Implant [ Time Frame: 5 years ]
    As determined by independent radiographic lab, this is the average measure of disc height at the index level(s) in both treatment groups at 5 years.
13. Change From Pre-Op Anterior Disc Height (mm) - At Level(s) of Implant [ Time Frame: 5 years ]
    As determined by independent radiographic lab, this is the average change from baseline for anterior disc height at the index level(s) in both treatment groups at 5 years.
14. Change From Pre-Op Posterior Disc Height (mm) - At Level(s) of Implant [ Time Frame: 5 years ]
    As determined by independent radiographic lab, this is the average change from baseline for posterior disc height at the index level(s) in both treatment groups at 5 years.
15. Change From Pre-Op Average Disc Height (mm) - At Level(s) of Implant [ Time Frame: 5 years ]
    As determined by independent radiographic lab, this is the average change from baseline for disc height at the index level(s) in both treatment groups at 5 years.
16. Change From Post-Op Anterior Disc Height (mm) - At Level(s) of Implant [ Time Frame: 5 years ]
    As determined by independent radiographic lab, this is the average change from immediate post-op for anterior disc height at the index level(s) in both treatment groups at 5 years.
17. Change From Post-Op Posterior Disc Height (mm) - At Level(s) of Implant [ Time Frame: 5 years ]
    As determined by independent radiographic lab, this is the average change from immediate post-op for posterior disc height at the index level(s) in both treatment groups at 5 years.
18. Change From Post-Op Average Disc Height (mm) - At Level(s) of Implant [ Time Frame: 5 years ]
    As determined by independent radiographic lab, this is the average change from immediate post-op for disc height at the index level(s) in both treatment groups at 5 years.
19. Disc Angle in Degrees - At Level(s) of Implant [ Time Frame: 5 years ]
    As determined by independent radiographic lab, this is the mean disc angle at the index level(s) in both treatment groups at 5 years.
20. Change From Pre-Op Disc Angle in Degrees - At Level(s) of Implant [ Time Frame: 5 years ]
    As determined by independent radiographic lab, this is the mean change in disc angle from baseline at the index level(s) in both treatment groups at 5 years.
21. Change From Post-Op Disc Angle in Degrees - At Level(s) of Implant [ Time Frame: 5 years ]
    As determined by independent radiographic lab, this is the mean change in disc angle from immediate post-op at the index level(s) in both treatment groups at 5 years.
22. Change From Post-Op Spondylolisthesis (mm) - At Level(s) of Implant [ Time Frame: 5 years ]
    As determined by independent radiographic lab, this is the measure of spondylolisthesis at the index level(s) in both treatment groups at 5 years.
23. Change From Post-Op Spondylolisthesis (%) - At Level(s) of Implant [ Time Frame: 5 years ]
    As determined by independent radiographic lab, this is the measure of the percentage of spondylolisthesis at the index level(s) in both treatment groups at 5 years.
24. Change From Pre-Op Spondylolisthesis (mm) - At Level(s) of Implant [ Time Frame: 5 years ]
    As determined by independent radiographic lab, this is the mean change in measure of spondylolisthesis at the index level(s) in both treatment groups at 5 years.
25. Change From Post-Op Spondylolisthesis (mm) - At Level(s) of Implant [ Time Frame: 5 years ]
    As determined by independent radiographic lab, this is the mean change in measure of spondylolisthesis from immediate post-op at the index level(s) in both treatment groups at 5 years.
26. Foraminal Height (X-ray) (mm) - At Level(s) of Implant [ Time Frame: 5 years ]
    This is the mean foraminal height via x-ray at the index level(s) in both treatment groups at 5 years.
27. Change From Pre-Op Foraminal Height (X-ray) (mm) - At Level(s) of Implant [ Time Frame: 5 years ]
    This is the mean change in foraminal height via x-ray from baseline at the index level(s) in both treatment groups at 5 years.
28. Change From Post-Op Foraminal Height (X-ray) (mm) - At Level(s) of Implant [ Time Frame: 5 years ]
    This is the mean change in foraminal height via x-ray from immediate post-op at the index level(s) in both treatment groups at 5 years.
29. Bony Bridging [ Time Frame: 5 years ]
    Bridging through the posterolateral gutters, between the facet joints, between transverse processes, and/or between facet joint and transverse process will all be considered acceptable forms of bridging bone.
30. Heterotopic Ossification [ Time Frame: 5 years ]
    Assessment applicable to coflex arm only. The assessment applies to bony formations that occur in and around the implant.
31. Fusion Status [ Time Frame: 5 years ]
    The assessment is an analysis of three component factors: Bridging Bone, Angular Motion and Translational Motion.
32. Interface Remodeling - At Level(s) of Implant [ Time Frame: 5 years ]
    Per level; Assessment applicable to coflex arm only. This is an assessment of the bone-implant interface.
33. Device Condition (Coflex Arm) [ Time Frame: 5 years ]
    Per level; Assessment only applicable to coflex group. Device Condition in the investigational subjects was graded as: Intact, Deformed, Fractured, Migrated, or Dislodged.
34. Device Condition (Fusion Control) [ Time Frame: 5 years ]
    Per level; This assessment is applicable to the fusion arm only. Device Condition in the control subjects will be graded as: Intact, Loose Screws, or Failed Hardware.
35. Device Mobility [ Time Frame: 5 years ]
    Per level; Assessment is applicable to coflex arm only. Device Mobility is an expected occurrence in some subjects and represents the amount of the of lift-off of the implant from the inferior spinous process.

Eligibility Criteria

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

Contacts and Locations

No Contacts or Locations Provided

More Information

Additional Information:

Related Info 

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):

Davis R, Auerbach JD, Bae H, Errico TJ. Can low-grade spondylolisthesis be effectively treated by either coflex interlaminar stabilization or laminectomy and posterior spinal fusion? Two-year clinical and radiographic results from the randomized, prospective, multicenter US investigational device exemption trial: clinical article. J Neurosurg Spine. 2013 Aug;19(2):174-84. doi: 10.3171/2013.4.SPINE12636. Epub 2013 May 31.

• Responsible Party: Paradigm Spine
• ClinicalTrials.gov Identifier: NCT00534235
• Other Study ID Numbers: PS-001
• First Posted: September 24, 2007
• Results First Posted: February 27, 2019
• Last Update Posted: February 6, 2020
• Last Verified: January 2020

Individual Participant Data (IPD) Sharing Statement:

• Plan to Share IPD: Undecided

Additional relevant MeSH terms:

Spinal Stenosis; Constriction, Pathologic; Pathological Conditions, Anatomical; Spinal Diseases; Bone Diseases; Musculoskeletal Diseases