In 2004 the posterior intervertebral cages in most common use
were the Ray (A), BAK (C), and Michelson (E) devices. Each
of these cages was specifically approved by the FDA in 1996 for
posterior interbody use (one or two cages).Although
not identified as such by name the A-NW ban was directed at the single
use of a posterior interbody Ray titanium cage because it was deemed,
in 2004, to
be "experimental." It is interesting to note that the
inventor of this cage, Charles D. Ray, M.D. (spine neurosurgeon)
used it at A-NW hospital starting in 1989 and that one of the
national IDE investigational studies on this cage was performed
under the auspices of the A-NW IRB committee. Until the
time that the FDA released the Ray cage for "full marketing" in
1996 it's status was "investigational." The "experimental"
stage of cage development was carried out on animals prior to
1989.
When the titanium cages noted above were approved for full
marketing use in 1996 following successful IRB approved national
studies this approval was the cages to be used as "standalone"
devices. This means that they were approved to be used
alone and not with additional stabilization. The
standalone status has continued to be successful. This is
particularly true because these devices require less cost and
operating time and have demonstrated a high safety and efficacy
when used selectively by experienced spinal surgeons.
Single Ray posterior interbody cages (as opposed to twin cages)
were first used at A-NW hospital in 1968. In 2004 A-NW
decided that this one application was "experimental." The
posterior implantation of single titanium intervertebral cages
continues today at A-NW hospital by spine surgeons despite the
2004 ban on their use. |
