Development of Ultrasound to Measure In-vivo Dynamic Cervical Spine Intervertebral Disc Mechanics
Annual rept. 26 Dec 2012-26 Dec 2013
BETH ISRAEL DEACONESS MEDICAL CENTER BOSTON MA
Pagination or Media Count:
We developed a unique dual ultrasound system that can non-invasively measure IVD deformation and mechanical compliance ex-vivo, and provide real-time images of IVDs and dynamic vertebral motion in-vivo during simulated tasks relevant to acute and chronic cervical spine injury and disease. A semi-automated program was developed to track the motion of a user-specified region of interest that corresponds to the anterior and posterior bony profiles of cervical vertebrae. Dynamic IVD displacements of vertebrae C4-5 measured by US were consistent with direct measurements. For motion frequencies up to 8Hz, US accounted for 77-96 of the true IVD displacements. We developed a transfer function that modeled the non-linear displacement of human cadaveric cervical spine functional spine units FSU as a function of an applied sinusoidal load that accounts for differential compliance and damping coefficients in tension and compression. A FEM of the cervical spine was updated to be more relevant to the military population. It has improved geometry, uses a finer mesh, has an increased number of elements and includes an additional spine segment. These refinements will improve the capability of the FEM to simulate different types of loadings and expand the models responsiveness making it more suitable to carry out parametric studies. We developed a diagnostic system that applies dynamic cyclic loads to cervical spine over a range of programmable frequencies and amplitudes that simulate operational conditions.
- Medicine and Medical Research