Page 32 - PCH Magazine Issue Jan export v3

THE HISTORY OF ARTIFICIAL

DISC REPL ACEMENTS

Artificial Disc replacement surgery or ADR endplates and insufficient instrumentation for
is a procedure which doctors remove a herniated or implantation caused Mark II to fail. The first two
damaged disc and replace it with an artificial disc. SB Charité implants never become commercially

This procedure allows you to maintain mobility available and was only used in the Charité hospital.
in your back. It is a common alternative to spinal In 1987 they produced the SB Charité III. It was made
fusion and an excellent choice for someone who of cobalt chromium alloy and the end plates are
participates in sports. ADR also helps prevent coated with titanium and hydroxyapatite porous to
adjacent disc degeneration. maximize osseointegration (the direct connection

The first disc replacement performed was between the bone and implant). This implant is
in late 1950s by Swedish doctor Ulf Fernstrom. still used today and has a 3-part component setup.
The procedure involved implanting a steel ball to It is designed to imitate a regular disc to maintain
replace the damaged disc. The steel balls’ purpose movement in the spine. The Charité has a total
was to maintain the disc space, height, and of 5 anchoring teeth to fixate the disc into place.

motion. Unfortunately, the procedure failed due These teeth help prevent disc migration.
to excessive compressive load concentration with When implanting the disc, the teeth are pressed
subsident into the subchondral bone. Even though into the lower and upper vertebrae. Over time the
the procedure failed it kick started research surrounding bone will grow over the plates. This
on better artificial disc designs. Researchers will secure the artificial disc more. The Charité

often looked towards knee and hip implants for also maintains the disc space to prevent spinal
reference when designing the new discs. collapse. The disc can maintain mobility because
It wasn’t until 1980 when Schellnack and Buttner- of its core. This core is made up of polyethylene,
janz initiated the first prosthesis design to be a very dense material and is located between the
distributed. It was called the SB Charité. The first two plates.

version failed due to
axial migrations and
stress concentrations
along the surface area.
This caused subsidence

into the vertebral body.
However, this failure
did not discourage
Schellnack and
Buttner-Janz instead

they modified the
original and came up
with the SB Charité II.
In the SB Charité II the
metal end plates were

enlarged. Fractures
in the SB Charité II