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

Post-Approval Study to Investigate The Long Term (5-Year) Survivorship of Coflex Compared to Control Fusion Study Patients

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

Study Overview

• Status: Completed
• Conditions: Spinal Stenosis
• Intervention / Treatment: Procedure: Decompression; Device: Posterolateral Fusion and Implantation of Pedicle Screws; Device: Implantation of coflex Interlaminar Technology

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 Type: Interventional
• Enrollment (Actual): 322
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / 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

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Subjects With Improvement of at Least 15 Points in ODI	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).	5 years
Number of Subjects With no Reoperations, Revisions, Removals, or Supplemental Fixation	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).	5 years
Number of Subjects With no Major Device Related Complications	Assessment of major device-related complications at 5 years	5 years
Number of Subjects With no Epidural Injection(s)	Assessment of lumbar epidural injections	5 years
Number of Subjects With no Persistent New or Increasing Sensory or Motor Deficit	No persistent new or increasing sensory or motor deficit	5 years
Number of Subjects With no Persistent New or Increasing Sensory Deficit	No persistent new or increasing sensory deficit	5 years
Number of Subjects With no Persistent New or Increasing Motor Deficit	No persistent new or increasing motor deficit	5 years
Number of Subjects With no Reoperations or Epidural (Up to Day 1825)	No reoperations, revisions, removals or supplemental fixation and no epidural injection at any lumbar level up to and including the Month 60 visit.	5 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Subjects With a Decrease in Zurich Claudication Questionnaire (ZCQ) Symptom Severity of at Least 0.5 Points	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.	5 years
Number of Subjects With Decrease in Zurich Claudication Questionnaire (ZCQ) Physical Function of at Least 0.5 Points	ZCQ is a scale that measures physical function, symptom severity, and patient satisfaction for patients with spinal stenosis.	5 years
Number of Subjects With Maintenance or Improvement in SF-12 Physical Function Component	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 years
Number of Subjects With Maintenance or Improvement in SF-12 Mental Health Component	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 years
Number of Subjects With a Decrease in VAS Back Pain of at Least 20mm	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.	5 years
Number of Subjects With Decrease VAS Worse Leg Pain of at Least 20mm	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.	5 years
Mean Oswestry Disability Index (ODI) Score	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.	5 years
Mean Visual Analog Scale Back Pain Score	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.	5 years
Mean Visual Analog Scale Leg (Worse) Pain Score	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.	5 years
Mean Visual Analog Scale (VAS) Leg (Right) Pain Score	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.	5 years
Mean Visual Analog Scale (VAS) Leg (Left) Pain Score	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.	5 years
Number of Subjects With a Decrease in VAS Right Leg Pain of at Least 20mm	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.	5 years
Number of Subjects With a Decrease in VAS Left Leg Pain of at Least 20mm	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.	5 years
Mean Zurich Claudication Questionnaire (ZCQ) Symptom Severity Score	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.	5 years
Mean Zurich Claudication Questionnaire (ZCQ) Physical Function Score	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.	5 years
Mean Short Form-12 Physical Component Score	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.	5 years
Mean Short Form-12 Mental Component Score	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.	5 years
Patient Survey: Satisfaction	Subjects who responded "Very Satisfied" or "Somewhat Satisfied".	5 years
Patient Survey: Recommendation of Treatment	Subjects who responded "Definitely Yes" or "Probably Yes"	5 years
Pain Management: Class II Narcotics Usage by Device Group	Number of subjects using Class II narcotics	5 years
Pain Management: NSAIDs/ASA/Acetaminophen Usage by Device Group	Number of subjects using NSAIDs/ASA/Acetaminophen	5 years

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean Rotation (F to E) in Degrees - At Level(s) of Implant	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.	5 years
Rotation (F to E) in Degrees - Below Level of Implant	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.	5 years
Rotation (F to E) in Degrees - Above Level of Implant	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.	5 years
Translation (mm) - At Level(s) of Implant	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 years
Translation (mm) - Below Level of Implant	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.	5 years
Translation (mm) - Above Level of Implant	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.	5 years
Anterior Disc Height (mm) - At Level(s) of Implant	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.	5 years
Posterior Disc Height (mm) - At Level(s) of Implant	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.	5 years
Translation (F to E) in Percent (%) - At Level(s) of Implant	As determined by independent radiographic lab, this is the percentage of translation at the index level(s) in both treatment groups at 5 years.	5 years
Translation (F to E) in Percent (%) - Below Level of Implant	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.	5 years
Translation (F to E) in Percent (%) - Above Level of Implant	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.	5 years
Average Disc Height (mm) - At Level(s) of Implant	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.	5 years
Change From Pre-Op Anterior Disc Height (mm) - At Level(s) of Implant	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.	5 years
Change From Pre-Op Posterior Disc Height (mm) - At Level(s) of Implant	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.	5 years
Change From Pre-Op Average Disc Height (mm) - At Level(s) of Implant	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.	5 years
Change From Post-Op Anterior Disc Height (mm) - At Level(s) of Implant	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.	5 years
Change From Post-Op Posterior Disc Height (mm) - At Level(s) of Implant	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.	5 years
Change From Post-Op Average Disc Height (mm) - At Level(s) of Implant	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.	5 years
Disc Angle in Degrees - At Level(s) of Implant	As determined by independent radiographic lab, this is the mean disc angle at the index level(s) in both treatment groups at 5 years.	5 years
Change From Pre-Op Disc Angle in Degrees - At Level(s) of Implant	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.	5 years
Change From Post-Op Disc Angle in Degrees - At Level(s) of Implant	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.	5 years
Change From Post-Op Spondylolisthesis (mm) - At Level(s) of Implant	As determined by independent radiographic lab, this is the measure of spondylolisthesis at the index level(s) in both treatment groups at 5 years.	5 years
Change From Post-Op Spondylolisthesis (%) - At Level(s) of Implant	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.	5 years
Change From Pre-Op Spondylolisthesis (mm) - At Level(s) of Implant	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.	5 years
Change From Post-Op Spondylolisthesis (mm) - At Level(s) of Implant	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.	5 years
Foraminal Height (X-ray) (mm) - At Level(s) of Implant	This is the mean foraminal height via x-ray at the index level(s) in both treatment groups at 5 years.	5 years
Change From Pre-Op Foraminal Height (X-ray) (mm) - At Level(s) of Implant	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.	5 years
Change From Post-Op Foraminal Height (X-ray) (mm) - At Level(s) of Implant	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.	5 years
Bony Bridging	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.	5 years
Heterotopic Ossification	Assessment applicable to coflex arm only. The assessment applies to bony formations that occur in and around the implant.	5 years
Fusion Status	The assessment is an analysis of three component factors: Bridging Bone, Angular Motion and Translational Motion.	5 years
Interface Remodeling - At Level(s) of Implant	Per level; Assessment applicable to coflex arm only. This is an assessment of the bone-implant interface.	5 years
Device Condition (Coflex Arm)	Per level; Assessment only applicable to coflex group. Device Condition in the investigational subjects was graded as: Intact, Deformed, Fractured, Migrated, or Dislodged.	5 years
Device Condition (Fusion Control)	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.	5 years
Device Mobility	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.	5 years

Collaborators and Investigators

• Sponsor: Paradigm Spine
• Collaborators: MCRA

Publications and helpful links

General Publications

• 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.

Helpful Links

• Related Info

Study record dates

Study Major Dates

• Study Start: October 1, 2012
• Primary Completion (Actual): December 1, 2015
• Study Completion (Actual): December 1, 2015

Study Registration Dates

• First Submitted: September 20, 2007
• First Submitted That Met QC Criteria: September 21, 2007
• First Posted (Estimate): September 24, 2007

Study Record Updates

• Last Update Posted (Actual): February 6, 2020
• Last Update Submitted That Met QC Criteria: January 24, 2020
• Last Verified: January 1, 2020

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Pathological Conditions, Anatomical; Spinal Diseases; Bone Diseases; Constriction, Pathologic; Spinal Stenosis
• Other Study ID Numbers: PS-001

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED