Most cervical spine pathology (ruptured
discs, bone spurs) must be addressed from an anterior approach involving
complete removal of the disc (and bone spurs, or osteophytes) and placement
of a bone graft "spacer" in its place. This prevents collapse
of the interspace and resulting compromise of the neuroforamen, where the
nerve roots exit. Because of this, anterior cervical discectomy (disc removal)
and fusion, or ACDF, has become the mainstay of cervical spine surgery for
many years.
There is some evidence that this alters the normal biomechanics of the spine,
resulting in more stress on the levels above and below the fusion, as these levels
must somehow "compensate" or bear the extra load that is involved with
everyday motion.
So was born the idea of motion preservation, and ultimately, artificial discs
(a.k.a disc arthroplasty). As an alternative to cervical fusion, this promising
new technology preserves motion with the goal of maintaining normal physiology
and biomechanics.
Short-term results have been promising, but long-term data is lacking. For younger
patients with single-level cervical disease (and well-preserved facet joints),
this is a very good option to consider as it may preserve strain on the adjacent
levels over many years to come. There are exclusion criteria, mainly advanced
age, degeneration of the facet joints, and multilevel pathology, among others.
An honest, detailed discussion should take place about the pros and cons of disc
replacement versus fusion, as many factors come into play and there is not a "one
size fits all" approach to any one particular case. Anterior cervical discectomy
and fusion (ACDF, or ACF) has a long track record of success over many years.
The idea of preventing adjacent segment disease (by preserving motion) has not
been proven long-term, but this is obviously an ongoing project.
Because of this, many insurance providers simply do not consider disc replacement
an option. However, because of the short-term results, large number of patients,
and low complication rates, more insurance carriers are approving this new technology
for their patients on a case-by-case basis.
Artificial Cervical Disc Replacement Video