Adjacent Segment Mechanics in Cervical Arthrodesis Patients

Study Purpose

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.

Recruitment Criteria

Accepts Healthy Volunteers

Healthy volunteers are participants who do not have a disease or condition, or related conditions or symptoms

Study Type

An interventional clinical study is where participants are assigned to receive one or more interventions (or no intervention) so that researchers can evaluate the effects of the interventions on biomedical or health-related outcomes.

An observational clinical study is where participants identified as belonging to study groups are assessed for biomedical or health outcomes.

Searching Both is inclusive of interventional and observational studies.

Eligible Ages 21 Years - 60 Years
Gender All
More Inclusion & Exclusion Criteria

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.

Trial Details

Trial ID:

This trial id was obtained from, a service of the U.S. National Institutes of Health, providing information on publicly and privately supported clinical studies of human participants with locations in all 50 States and in 196 countries.


Phase 1: Studies that emphasize safety and how the drug is metabolized and excreted in humans.

Phase 2: Studies that gather preliminary data on effectiveness (whether the drug works in people who have a certain disease or condition) and additional safety data.

Phase 3: Studies that gather more information about safety and effectiveness by studying different populations and different dosages and by using the drug in combination with other drugs.

Phase 4: Studies occurring after FDA has approved a drug for marketing, efficacy, or optimal use.

Lead Sponsor

The sponsor is the organization or person who oversees the clinical study and is responsible for analyzing the study data.

University of Pittsburgh
Principal Investigator

The person who is responsible for the scientific and technical direction of the entire clinical study.

William Anderst, PhD
Principal Investigator Affiliation University of Pittsburgh
Agency Class

Category of organization(s) involved as sponsor (and collaborator) supporting the trial.

Overall Status Recruiting
Countries United States

The disease, disorder, syndrome, illness, or injury that is being studied.

Intervertebral Disc Degeneration
Additional Details

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.

Arms & Interventions


: 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

: C6-C7 arthrodesis

Patients scheduled to undergo C6-C7 anterior cervical arthrodesis

: C4-C5-C6 arthrodesis

Patients scheduled to undergo C4-C5-C6 anterior cervical arthrodesis

: 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.

Contact a Trial Team

If you are interested in learning more about this trial, find the trial site nearest to your location and contact the site coordinator via email or phone. We also strongly recommend that you consult with your healthcare provider about the trials that may interest you and refer to our terms of service below.

University of Pittsburgh Biodynamics Lab, Pittsburgh, Pennsylvania




University of Pittsburgh Biodynamics Lab

Pittsburgh, Pennsylvania, 15203

Site Contact

Lisa Bemis

[email protected]