Biff--great find.
Very intriguing, especially this:
"It is felt that restrictions in disc prosthesis design may not only create a performance liability, but are also not needed. The surrounding ligaments, muscles, and other tissues provide a built-in restriction to anterior/posterior, medial-lateral, and twisting motions of the artificial intervertebral disc, at least to a point in which adjacent discs are not significantly affected. "
Pretty bold statement if I understood that correctly, and not sure everyone would agree there...am I assuming correctly that the author favors unconstrained designs on the premise that other body structures will beat the prosthesis into submission should it get rowdy?
Not too comfortable with that at first glance. Aren't surrounding structures also vulnerable to oversolicitation and fatigue, often making them secondary or tertiary pain generators? And in the degenrative cascade, couldn't these then have adverse effects on other discs down the line, even assuming the unconstrained prosthesis itself would not?
Trace