Adjacent Segment Mechanics in Cervical Arthrodesis Patients

February 3, 2025 updated by: William Anderst, University of Pittsburgh
This study aims to determine to what extent patient-specific factors, iatrogenic factors, and biomechanical factors influence cervical spine mechanics after single-level and two-level arthrodesis.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

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

The etiology of adjacent segment pathology following cervical fusion remains highly controversial. Adjacent segment disease is believed to result from one or more of the following distinct causes:

  1. the natural history of the adjacent disc;
  2. disruption of the adjacent segment anatomy due to the initial surgery; and
  3. biomechanical stress on the adjacent level following the fusion.

The long-term goal of our research is to reduce or prevent symptomatic adjacent segment degeneration in the spine. The overall hypothesis of this study is that adjacent segment kinematics (i.e. translations, rotations, helical axis of motion) and arthrokinematics (i.e. disc deformation and facet joint surface interactions) after ACDF are determined primarily by patient-specific anatomy and iatrogenic factors, and not by increased biomechanical stress due to the fusion.

A prospective longitudinal study is proposed to determine to what extent patient-specific factors (Specific Aim 1), iatrogenic factors (Specific Aim 2), and altered biomechanics (Specific Aim 3) affect dynamic cervical spine function following fusion. Participants will be C56 (n=22) and C67 (n=22) single-level fusion patients, C456 (n=22) and C567 (n=22) two-level fusion patients, and asymptomatic controls similar in age to the fusion patients (n=22). Patients will be tested prior to surgery, one year post-surgery, and three years post-surgery. At each test, participants will complete clinical questionnaires to assess pain and function, and they will perform full range of motion flexion\extension and axial rotation of the head and cervical spine while biplane radiographs are recorded at 30 images per second. A highly accurate and validated volumetric model-based tracking process and custom data analysis software will be utilized to determine intervertebral kinematics (i.e. translations, rotations, helical axis of motion) and arthrokinematics (i.e. disc deformation and facet joint surface interactions) at each test session.

This prospective study will identify the factors that have the greatest effect on adjacent segment mechanics after cervical fusion. If the hypotheses are confirmed, this will provide support for increased attention to patient-specific factors and surgical technique. Alternatively, if the results indicate that adjacent segment mechanics are influenced primarily by increased stress after arthrodesis, this will provide support for increased attention to the design of motion-sparing devices.

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.
Observational

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.
106

Contacts and Locations

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

Study Locations

  • United States
    • Pennsylvania
      • Pittsburgh, Pennsylvania, United States, 15203
        • University of Pittsburgh Biodynamics Lab

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

17 years to 56 years (Adult)

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

All patients will be between 21 and 60 years of age and will be scheduled to undergo single-level or two-level anterior cervical discectomy and fusion (ACDF) at the C56, C67, C456 or C567 levels. Indications for surgical intervention will be progressive symptoms refractory to conservative treatment for myelopathy, radiculopathy, or myeloradiculopathy resulting from degenerative spondylosis, symptomatic cervical disc herniation, or symptomatic disc degeneration.

Description

Inclusion Criteria:

  • Patients must agree to return for all follow-up visits and provide informed consent.
  • Control subjects will be asymptomatic, with no injury or disease that will interfere with spine function, such as previous spine surgery or trauma.

Exclusion Criteria:

  • Participants will have no other injury or disease that will interfere with spine function, such as previous spine surgery or trauma
  • Individuals who have been previously clinically diagnosed with poor bone quality and those who do not intend to stay in the Pittsburgh area for a period of at least 3 years post-surgery will be excluded.
  • Females who are pregnant or plan to be pregnant within 3 years of surgery will be excluded.

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

  • Observational Models: Case-Control
  • Time Perspectives: Prospective

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
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.
Asymptomatic Controls
Individuals who have no history of neck pain, trauma or surgery, similar in age and sex to the surgical patients
C5-C6 arthrodesis
Patients scheduled to undergo C5-C6 anterior cervical arthrodesis
Procedure: C5-C6 arthrodesis
A standard Smith Robinson anterior medial approach to the cervical spine. Vertebral endplates will be prepared by removing the cartilage endplate. Tricortical anterior iliac crest autografts will be harvested with a low-speed oscillating saw. Allografts will be fresh-frozen, vacuum-sealed, nonradiated tricortical grafts. All grafts will be fashioned in a typical Smith-Robinson formation. The motion segment will be distracted approximately 2-mm beyond the graft height before the insertion of each graft. Fusion plate will be contoured to cervical lordosis. Cervical plates will be positioned using surgical midline markers. All rigid anterior plate fixations will be performed using titanium anterior fixed-angle screw systems.
C6-C7 arthrodesis
Patients scheduled to undergo C6-C7 anterior cervical arthrodesis
Procedure: C5-C6 arthrodesis
A standard Smith Robinson anterior medial approach to the cervical spine. Vertebral endplates will be prepared by removing the cartilage endplate. Tricortical anterior iliac crest autografts will be harvested with a low-speed oscillating saw. Allografts will be fresh-frozen, vacuum-sealed, nonradiated tricortical grafts. All grafts will be fashioned in a typical Smith-Robinson formation. The motion segment will be distracted approximately 2-mm beyond the graft height before the insertion of each graft. Fusion plate will be contoured to cervical lordosis. Cervical plates will be positioned using surgical midline markers. All rigid anterior plate fixations will be performed using titanium anterior fixed-angle screw systems.
C4-C5-C6 arthrodesis
Patients scheduled to undergo C4-C5-C6 anterior cervical arthrodesis
Procedure: C5-C6 arthrodesis
A standard Smith Robinson anterior medial approach to the cervical spine. Vertebral endplates will be prepared by removing the cartilage endplate. Tricortical anterior iliac crest autografts will be harvested with a low-speed oscillating saw. Allografts will be fresh-frozen, vacuum-sealed, nonradiated tricortical grafts. All grafts will be fashioned in a typical Smith-Robinson formation. The motion segment will be distracted approximately 2-mm beyond the graft height before the insertion of each graft. Fusion plate will be contoured to cervical lordosis. Cervical plates will be positioned using surgical midline markers. All rigid anterior plate fixations will be performed using titanium anterior fixed-angle screw systems.
C5-C6-C7 arthrodesis
Patients scheduled to undergo C5-C6-C7 anterior cervical arthrodesis
Procedure: C5-C6 arthrodesis
A standard Smith Robinson anterior medial approach to the cervical spine. Vertebral endplates will be prepared by removing the cartilage endplate. Tricortical anterior iliac crest autografts will be harvested with a low-speed oscillating saw. Allografts will be fresh-frozen, vacuum-sealed, nonradiated tricortical grafts. All grafts will be fashioned in a typical Smith-Robinson formation. The motion segment will be distracted approximately 2-mm beyond the graft height before the insertion of each graft. Fusion plate will be contoured to cervical lordosis. Cervical plates will be positioned using surgical midline markers. All rigid anterior plate fixations will be performed using titanium anterior fixed-angle screw systems.

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
Kinematics
Time Frame: pre-surgery to 3 years post-surgery
range of motion (ROM) in degrees
pre-surgery to 3 years post-surgery
Iatrogenic factors
Time Frame: pre-surgery to 3 years post-surgery
adjacent segment disc height and sagittal alignment; graft height, plate placement
pre-surgery to 3 years post-surgery
Kinematics
Time Frame: pre-surgery to 3 years post-surgery
The helical axis of motion (HAM)
pre-surgery to 3 years post-surgery
Kinematics
Time Frame: pre-surgery to 3 years post-surgery
The continuous 3D intervertebral kinematics (translations and rotations).
pre-surgery to 3 years post-surgery
Arthrokinematics
Time Frame: pre-surgery to 3 years post-surgery
Disc deformation
pre-surgery to 3 years post-surgery
Arthrokinematics
Time Frame: pre-surgery to 3 years post-surgery
Facet joint capsule deformation
pre-surgery to 3 years post-surgery

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.
University of Pittsburgh

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.
  • Principal Investigator: William Anderst, PhD, University of Pittsburgh

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.
April 1, 2016

Primary Completion (Actual)

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 30, 2024

Study Completion (Actual)

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 30, 2024

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).
February 10, 2016

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.
January 19, 2017

First Posted (Estimated)

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.
January 23, 2017

Study Record Updates

Last Update Posted (Actual)

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.
March 25, 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.
February 3, 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.
September 1, 2024

More Information

Terms related to this study

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.
  • STUDY19070070

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

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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