Machine may speed up
Approval for Spinal Implants
July 28th 2005
The Human Spine
The Mechanical Engineering
Department at Purdue University is developing specialized hydraulic
machines and software to test orthopedic devices for the spine. The
team is using machines to test spinal implants for the lower or lumbar
regions of the spine, and cervical, or neck region of the spine.
Ben Hillberry, professor of
mechanical Engineering is leading the research and is working with
Purpue’s Weldon School of Biomedical Engineering. Ben and his
colleagues are attaching implants made by various manufacturers to
cadavers and then the spines are tested using a hydraulic machine.
The machine is designed to mimic
everyday activities to determine how the implants “stand up”. "Creating
implants for the spine presents interesting challenges, different from
those encountered in implants for other parts of the body, such as the
hips and knees," said Eric Nauman, an assistant professor of mechanical
The machines test various materials
and shapes. One machine tests implants for the cervical spine. The
goal is to replicate the motions seen in the human neck. "There is much
more movement in the cervical spine than in the lumbar portion, so what
we are primarily testing with this machine is how well implants will
stand up to wear over a period of about 10 years," said Shreekant
Gayakar, a graduate student in mechanical engineering.
Researchers also are using the spine simulator to test
implants that replace diseased "facet joints." The facet joints are
often damaged by
arthritis and usually are treated by injecting them
with compounds to relieve the pain. Unlike other arthritic joints, such
as hips, knees and shoulders, facet joints have not, until recently,
been removed and replaced with artificial implants.
Scientists are hoping to develop replacement devices
for the spine. Currently the common method for treating spinal
conditions is fusing several vertebrae together.
Replacements may work better giving patients motion and stability,
typically lost with today’s procedures.
The model also can be used to help develop better ways
to straighten the spine for people who have
scoliosis, or a curvature of
Hillberry says "In order for implants to be approved
by the Food and Drug Administration, it has to be shown that they can
last 10 million cycles, or 10 million movements, which translates into
about 10 years of living," The goal of the team is to complete 10
million cycles over a four-month period.
Hopefully these testing machines will help speed
approval of implants while determining which implants work best. There
are not many machines that can duplicate the motions of the human
spine. “I know of only one on the market," said Jeremie Wade, a
graduate student in mechanical engineering who is involved in research
using the machine. Purdue Website: http://news.uns.purdue.edu/UNS/html4ever/2005/050720.Hillberry.spine.html
Best Syndication Staff Writer
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