A Biomechanical Assessment of the AST Stabilimax BAR Using Radiostereometric Analysis (RSA)

Assessment of segmental spine motion has been and continues to be, a difficult clinical problem. Errors of up to 10 degrees for simple measurements of flexion, extension and side bending have been recorded using conventional radiographs (xrays.) These errors are usually associated with the inability to acquire three-dimensional positions and inaccurate reference points. It has, therefore, been extremely difficult to measure small changes in vertebral alignment, which may prove to be an early, clinically significant, indicator of potential problems. Radiostereometric Analysis, or RSA, is an accurate in vivo measurement technique using two simultaneous radiographs. It provides researchers with three dimensional motion analyses to look not only at routine flexion/extension, but also other rotational and translational changes. The measurement accuracy offered by this technique far exceeds the manual techniques currently used. The purpose of this study is to assess the amount of motion in the lumbar spine in patients with the AST Stabilimax BAR. The AST Stabilimax BAR is designed to allow for motion in the spine while providing the necessary stability to the spinal segment. The amount and degree of this motion is currently unknown clinically. By using tantalum bead markers placed in the spine at the time of the surgery, RSA analysis can determine the amount and degree of motion of the implanted construct. Two questions will be examined with this data: 1) what is the amount of sagittal and coronal plane motion that occurs in vivo with the AST Stabilimax BAR system? and 2) will this change over the 2 year time frame for this study?

Study Overview

Detailed Description

Radiostereometric Analysis, or RSA, is an accurate in vivo measurement technique using two simultaneous radiographs. It provides researchers with three dimensional motion analyses to look not only at routine flexion/extension, but also other rotational and translational changes. The measurement accuracy offered by this technique far exceeds the manual techniques currently used. Utilization of the RSA technology at the IHP and the United States is in its infancy. The investigators have placed much effort over the past 2-3 years to put the necessary dedicated resources and personnel in place. This has been a collaborative effort between the Department of Orthopedic Surgery and the Imaging Core at IHP. Preliminary work on the accuracy, reliability, and surgical planning for use of RSA has been completed and presented at national conferences.

The purpose of this study is to assess the amount of motion in the lumbar spine in patients with the AST Stabilimax BAR. The AST Stabilimax BAR is designed to allow for motion in the spine while providing the necessary stability to the spinal segment. The amount and degree of this motion is currently unknown clinically, but has been biomechanically tested in vitro. By using tantalum bead markers placed in the spine at the time of the surgery, RSA analysis can determine the amount and degree of motion the implant provides. Two questions will be examined with this data: 1) what is the amount of sagittal and coronal plane motion that occurs in vivo with the AST Stabilimax BAR system? and 2) will this change over the 2 year time frame for this study?

Study Type

Observational

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

    • New York
      • Syracuse, New York, United States, 13202
        • SUNY Upstate Medical University

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

Ages Eligible for Study

18 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

This is a single-center, non-randomized study. 10 Subjects who are identified to receive the AST Stabilimax BAR device will be approached to participate in this study. All subjects will receive 10 RSA tantalum beads (5 in each vertebra) at the time of their lumbar surgery. After surgery, subjects will have the biplanar xrays taken. The biplanar xrays will be taken from 5 standing positions: neutral, flexion (bending forward), extension (bending backwards), left side bending, and right side bending. RSA analysis will be completed to determine the amount of motion on sagittal and coronal planes.

Description

Inclusion Criteria:

  • Subjects scheduled to have lumbar surgery to receive the AST Stabilimax BAR
  • All subjects must be skeletally mature, between the ages of 18-75

Exclusion Criteria:

  • Pregnant women will be excluded due to added radiation exposure
  • Prisoners will also 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

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
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Radiostereometric Analysis, or RSA, is an accurate in vivo measurement technique using two simultaneous radiographs. It provides researchers with three dimensional motion analyses to look not only at routine flexion/extension, but also other rotational and translational changes

Collaborators and Investigators

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

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

October 1, 2006

Primary Completion (Actual)

October 1, 2008

Study Completion (Actual)

October 1, 2008

Study Registration Dates

First Submitted

March 4, 2008

First Submitted That Met QC Criteria

March 4, 2008

First Posted (Estimate)

March 13, 2008

Study Record Updates

Last Update Posted (Estimate)

May 25, 2015

Last Update Submitted That Met QC Criteria

May 22, 2015

Last Verified

May 1, 2015

More Information

Terms related to this study

Other Study ID Numbers

  • Stabilimax Bar

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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