Models available for the study of intervertebral disc degeneration are
designed to answer many important questions. In vitro biologic models employ a
variety of cell, tissue, or organ culture techniques with culture conditions
that partially mimic the cellular environment of the degenerated human
intervertebral disc. In vitro biomechanical models include intervertebral disc
or motion-segment loading experiments as well as finite element modeling
techniques. The literature describes numerous in vivo animal models for use in
the study of intervertebral disc degeneration, each of which has its own
advantages and disadvantages. Human-subject studies have included the use of
magnetic resonance imaging and other techniques to assess diffusion into the
intervertebral disc, to measure intradiscal pressure, to conduct kinematic or
stiffness studies of lumbar motion segments, and to evaluate muscular forces
on the spine. Although all of these studies are helpful in answering specific
questions, their relevance in assessing disc degeneration in patients with
symptoms of discogenic pain must be carefully considered.