Adjacent Segment Mechanics in Cervical Arthrodesis Patients

NCT ID: NCT03028402

Last Updated: 2025-02-06

Basic Information

• Recruitment Status: COMPLETED
• Total Enrollment: 106 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2016-04-30
• Study Completion Date: 2024-12-30

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.

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.

Conditions

Intervertebral Disc Degeneration

Study Design

• Observational Model Type: CASE_CONTROL
• Study Time Perspective: PROSPECTIVE

Study Groups

Asymptomatic Controls

Individuals who have no history of neck pain, trauma or surgery, similar in age and sex to the surgical patients

No interventions assigned to this group

C5-C6 arthrodesis

Patients scheduled to undergo C5-C6 anterior cervical arthrodesis

C5-C6 arthrodesis

Intervention Type: PROCEDURE

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

C5-C6 arthrodesis

Intervention Type: PROCEDURE

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

C5-C6 arthrodesis

Intervention Type: PROCEDURE

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

C5-C6 arthrodesis

Intervention Type: PROCEDURE

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.

Interventions

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.

Intervention Type: PROCEDURE

Eligibility 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.

• Minimum Eligible Age: 21 Years
• Maximum Eligible Age: 60 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of Pittsburgh

OTHER

Sponsor Role: lead

Responsible Party

William Anderst

Associate Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

William Anderst, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Pittsburgh

Locations

University of Pittsburgh Biodynamics Lab

Pittsburgh, Pennsylvania, United States

Countries

United States

Other Identifiers

STUDY19070070

Identifier Type: -

Identifier Source: org_study_id