M6-C Artificial Cervical Disc Two-Level IDE Pivotal Study

November 12, 2025 updated by: Orthofix Inc.
Prospective, concurrently controlled, multi-center study to evaluate the safety and effectiveness of the Spinal Kinetics M6-C™ artificial cervical disc compared to anterior cervical discectomy and fusion (ACDF) for the treatment of contiguous two-level symptomatic cervical radiculopathy at vertebral levels from C3 to C7 with or without spinal cord compression.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Patients will be concurrently enrolled in the M6-C treatment group and the ACDF control group. Patients should have failed at least six weeks of conservative treatment or demonstrate progressive symptoms despite continued non-operative treatment. For the study, 263 patients will undergo either a two-level cervical artificial disc procedure, or an instrumented (ACDF) procedure as per site group assignment. Patients will be evaluated clinically, radiographically, and via the collection of patient-reported outcomes at 6 Weeks, 3 Months, 6 Months, 12 Months and 24 Months. The primary endpoint is Overall Success at 24 Months.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
156

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • Arizona
      • Phoenix, Arizona, United States, 85020
        • Desert Institute for Spine Care
    • California
      • Beverly Hills, California, United States, 90210
        • Beverly Hills Spine Surgery
      • Long Beach, California, United States, 90806
        • Memorial Orthopaedic Surgical Group
      • Newport Beach, California, United States, 92660
        • Disc Sports & Spine Center
      • Orange, California, United States, 92868
        • UC Irvine Medical Center
      • Santa Monica, California, United States, 90404
        • Institute of Neuro Innovation
      • Thousand Oaks, California, United States, 91860
        • St. Charles Spine Institute
    • Colorado
      • Aurora, Colorado, United States, 80045
        • University of Colorado School of Medicine - Department of Orthopedics
      • Vail, Colorado, United States, 81657
        • Steadman Philipon Research Institute
    • Florida
      • Orlando, Florida, United States, 32809
        • Orlando Health
      • Tampa, Florida, United States, 33607
        • Joseph Spine Institute
    • Georgia
      • Gainesville, Georgia, United States, 30801
        • Longstreet Clinic
    • Idaho
      • Coeur d'Alene, Idaho, United States, 83815
        • Axis Spine
    • Illinois
      • Urbana, Illinois, United States, 61801
        • Carle Health
    • Massachusetts
      • Boston, Massachusetts, United States, 02115
        • Brigham & Women's Hospital
    • Michigan
      • Southfield, Michigan, United States, 48033
        • Michigan Orthopedic Surgeons
    • Missouri
      • St Louis, Missouri, United States, 63017
        • The Orthopedic Center of St. Louis
    • New Jersey
      • Englewood, New Jersey, United States, 07631
        • Metropolitan Neurosurgery Associates - Englewood Health
    • Ohio
      • Cincinnati, Ohio, United States, 45209
        • Mayfield Clinic
    • Texas
      • Austin, Texas, United States, 78705
        • St. David's Healthcare
      • Frisco, Texas, United States, 75033
        • American Neurospine Institute/Medical City Frisco

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Diagnosis of degenerative cervical radiculopathy with or without spinal cord compression requiring surgical treatment at two contiguous levels from C3 to C7 demonstrated by signs and/or symptoms of disc herniation and/or osteophyte formation (e.g. neck and/or arm pain, radiculopathy, etc.) and is confirmed by patient history and radiographic studies (e.g. MRI, CT, x-rays, etc.)
  • Inadequate response to conservative medical care over a period of at least 6 weeks or have the presence of progressive symptoms or signs of nerve root/spinal cord compression in the face of continued non-operative management
  • Neck Disability Index score of ≥ 30% (raw score of ≥ 15/50)
  • Neck or arm pain Visual Analog Scale Score ≥ 4 on a scale of 0 to 10
  • Willing and able to comply with the requirements of the protocol including follow-up requirements
  • Willing and able to sign a study specific informed consent
  • Skeletally mature and at least 18 years old but not older than 75 years old

Exclusion Criteria:

  • More than two cervical levels requiring surgery, or two non-contiguous levels requiring surgery
  • Previous anterior cervical spine surgery
  • Axial neck pain as the solitary symptom
  • Previous posterior cervical spine surgery (such as a posterior element decompression) that destabilizes the cervical spine
  • Advanced cervical anatomical deformity (such as ankylosing spondylitis, scoliosis) at either of the operative levels or adjacent levels
  • Symptomatic facet arthrosis
  • Less than four degrees of motion in flexion/extension at either of the index levels
  • Instability as evidenced by subluxation greater than 3 millimeters at either of the index or adjacent levels as indicated on flexion/extension x-rays.
  • Advanced degenerative changes (e.g., spondylosis) at either of the index vertebral levels as evidenced by bridging osteophytes, central disc height less than 4 millimeters and/or < 50% of the adjacent normal intervertebral disc, or kyphotic deformity > 11 degrees on neutral x-rays
  • Severe cervical myelopathy (i.e., Nurick's Classification greater than 2)
  • Active systemic infection or infection at the operative site
  • Co-morbid medical conditions of the spine or upper extremities that may affect the cervical spine neurological and/or pain assessment
  • Metabolic bone disease such as osteoporosis that contradicts spinal surgery
  • History of an osteoporotic fracture of the spine, hip or wrist
  • History of an endocrine or metabolic disorder (e.g. Paget's disease) known to affect bone and mineral metabolism
  • Taking medications that may interfere with bony/soft tissue healing including chronic steroid use
  • Known allergy to titanium, stainless steels, polyurethane, polyethylene, or ethylene oxide residuals
  • Fibromyalgia, Rheumatoid Arthritis (or other autoimmune disease), or a systemic disorder such as HIV or acute hepatitis B or C.
  • Insulin dependent diabetes
  • Medical condition (e.g., unstable cardiac disease, cancer) that may result in patient death or have an effect on outcomes prior to study completion
  • Pregnant, or intend to become pregnant, during the course of the study
  • Severe obesity (Body Mass Index greater than 45)
  • Physical or mental condition (e.g. psychiatric disorder, senile dementia, Alzheimer's disease, alcohol or drug addiction) that would interfere with patient self-assessment of function, pain or quality of life.
  • Involved in current or pending spinal litigation where permanent disability benefits are being sought.
  • Incarcerated at time of study enrollment
  • Current participation in other investigational study.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: M6-C Artificial Cervical Disc
The M6-C is an investigational device composed of two outer and inner endplates made of titanium with a polycarbonate urethane nucleus (plastic center) and a polyethylene fiber annulus (strong thread-like binding). Around the polyethylene annulus is a polyurethane sheath (plastic cover). The outer endplates have keels to anchor the disc to bone. The outer endplates and keels are both coated with a titanium plasma spray. The M6-C is provided in two heights (6mm and 7mm) and four footprints (Medium, Medium Long, Large, Large Long).
Device: M6-C Artificial Cervical Disc
An incision will be made in the front of the neck and the damaged disc located between cervical vertebrae (neck bones) will be removed so that the M6-C artificial cervical disc can be placed into the space where the damaged disc was removed. This procedure will be performed using x-ray technology (fluoroscopy) guide the surgeon in placement of the M6-C in between the cervical vertebrae. This process will be repeated to replace the second damaged disc.
Active Comparator: Anterior Cervical Discectomy & Fusion (ACDF)

ACDF will be performed using one of four FDA-approved anterior cervical plate systems and corticocancellous allograft bone. The four plating systems used in this study are:

  • Orthofix CETRA Anterior Cervical Plate System
  • Medtronic Sofamor/Danek Venture Anterior Cervical Plate System
  • DePuy Synthes: SKYLINE Anterior Cervical Plate System
  • Stryker Aviator Anterior Cervical Plating System
Device: ACDF
One of four FDA-approved cervical plate systems will be used for the ACDF. An incision will be made in the front of the neck and the damaged disc located between cervical vertebrae (neck bones) will be removed. Then, a piece of donor bone will be placed in the space where the damaged disc was removed and a metal plate will be screwed into the bones above and below the disc. This procedure will be performed using x-ray technology (fluoroscopy) to guide the surgeon in the placement of the cervical plate system. This process will be repeated to treat the other damaged disc.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Functional Impairment - Neck Disability Index Score (NDI)
Time Frame: 24 Month
Change in condition-specific functional impairment will be evaluated using a 10 item NDI outcomes questionnaire to assess change in the functional impairment score. NDI scores range from 0-50 (0%-100%) with higher scores demonstrating greater disability.
24 Month
Overall Participant Success Rate (M6-C Artificial Cervical Disc)
Time Frame: 24 Month
- Participant success is a composite endpoint of all of the listed Primary Outcome Measures.
24 Month
- Serious Adverse Event(s)
Time Frame: 24 Month
No serious adverse events classified as device or device procedure related (as determined by the Clinical Events Committee).
24 Month
- Additional Surgical Intervention
Time Frame: 24 Month
No supplemental surgical procedure at the index level(s) including supplemental fixation, revision and/or device removal.
24 Month
- Neurologic Function
Time Frame: 24 Month
Maintenance or improvement in neurological function as determined by Clinical Events Committee review of neurological exam results.
24 Month

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Neck and Arm Pain
Time Frame: 24 Month
Change in severity of neck and arm pain will be evaluated on a 10-cm Visual Analog Scale (VAS). Zero = no pain, 10 = worst possible pain.
24 Month
Health-Related Quality of Life
Time Frame: 24 Month
Maintenance or improvement of health-related quality of life will be evaluated using the SF-12v2 Health Survey.
24 Month
Radiographic Assessments
Time Frame: 24 Month
Quantitative and qualitative assessments compared to baseline evaluating surgical success outcomes for both cohorts.
24 Month
FOSS Dysphagia Scale
Time Frame: 24 Month
The five-stage Functional Outcome Swallowing Scale (FOSS) will be used to determine presence/absence of post-operative oropharyngeal dysphagia and severity of the disorder and outcome. On the 0 to 4 FOSS scale, 0=normal; asymptomatic, whereas 5=severe dysphagia; nonoral feeding.
24 Month
Odom's Criteria
Time Frame: 24 Month
Physician assessment of the clinical disposition of a participant at two-years using the 4-point rating scale (excellent, good, satisfactory, poor) for assessing the clinical outcome after cervical spine surgery.
24 Month
Patient Satisfaction
Time Frame: 24 Month
A brief Participant Satisfaction Questionnaire (very satisfied, satisfied, neutral, unsatisfied, very unsatisfied) regarding the outcome of their surgery at two-years.
24 Month
Pain Medication Usage
Time Frame: 24 Months
Change in usage of post-operative pain medications specifically prescribed for cervical spine will be documented.
24 Months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Orthofix Inc.

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Spinal Kinetics

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Jay Erturan, MD, JD, Orthofix Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 26, 2021

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2025

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 17, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 23, 2021

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 29, 2021

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 14, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 12, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
November 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • CA-C003-Pivotal

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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