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Adjacent Segment Mechanics in Cervical Arthrodesis Patients

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ClinicalTrials.gov Identifier: NCT03028402
Recruitment Status : Recruiting
First Posted : January 23, 2017
Last Update Posted : October 11, 2018
Sponsor:
Information provided by (Responsible Party):
William Anderst, University of Pittsburgh

Brief Summary:
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.

Condition or disease Intervention/treatment
Intervertebral Disc Degeneration Procedure: C5-C6 arthrodesis

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 : Observational
Estimated Enrollment : 110 participants
Observational Model: Case-Control
Time Perspective: Prospective
Official Title: Adjacent Segment Mechanics in Cervical Arthrodesis Patients
Study Start Date : April 2016
Estimated Primary Completion Date : March 2021
Estimated Study Completion Date : March 2021

Resource links provided by the National Library of Medicine


Group/Cohort Intervention/treatment
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.




Primary Outcome Measures :
  1. Kinematics [ Time Frame: pre-surgery to 3 years post-surgery ]
    range of motion (ROM) in degrees

  2. Iatrogenic factors [ Time Frame: pre-surgery to 3 years post-surgery ]
    adjacent segment disc height and sagittal alignment; graft height, plate placement

  3. Kinematics [ Time Frame: pre-surgery to 3 years post-surgery ]
    The helical axis of motion (HAM)

  4. Kinematics [ Time Frame: pre-surgery to 3 years post-surgery ]
    The continuous 3D intervertebral kinematics (translations and rotations).

  5. Arthrokinematics [ Time Frame: pre-surgery to 3 years post-surgery ]
    Disc deformation

  6. Arthrokinematics [ Time Frame: pre-surgery to 3 years post-surgery ]
    Facet joint capsule deformation



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Ages Eligible for Study:   21 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
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.
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.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03028402


Contacts
Contact: William Anderst, PhD 412-586-3946 anderst@pitt.edu

Locations
United States, Pennsylvania
University of Pittsburgh Biodynamics Lab Recruiting
Pittsburgh, Pennsylvania, United States, 15203
Contact: Alexandra Maxim    412-586-3951    alexandra.maxim@pitt.edu   
Sponsors and Collaborators
University of Pittsburgh
Investigators
Principal Investigator: William Anderst, PhD University of Pittsburgh

Responsible Party: William Anderst, Assistant Professor, University of Pittsburgh
ClinicalTrials.gov Identifier: NCT03028402     History of Changes
Other Study ID Numbers: PRO16020186
First Posted: January 23, 2017    Key Record Dates
Last Update Posted: October 11, 2018
Last Verified: October 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

Additional relevant MeSH terms:
Intervertebral Disc Degeneration
Spinal Diseases
Bone Diseases
Musculoskeletal Diseases